Littérature scientifique sur le sujet « MPC controller »
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Articles de revues sur le sujet "MPC controller"
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Hou, Juan, Haoran Li et Natasa Nord. « Optimal control of secondary side supply water temperature for substation in district heating systems ». E3S Web of Conferences 111 (2019) : 06015. http://dx.doi.org/10.1051/e3sconf/201911106015.
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Low temperature is the most significant feature of the future district heating system- the 4th generation district heating (4GDH). However, a widely used control strategy for supply water temperature in substation is weather- compensated control. It is a feedforward control without any dynamic information about buildings, which can lead to higher or lower supply water temperature. This paper presents model predictive controller (MPC) applied to the supply water temperature control for substations in district heating systems. MPC is an advanced control technique, which can make full use of dynamic information of buildings to determine the optimal supply water temperature of substations. In this paper, a multiple inputs and single output dynamic model was identified by subspace methods. Two different MPC controllers were designed in Simulink. The MPC controller 1 focused on keeping indoor air temperature at reference values. The MPC controller 2 focused on both keeping indoor air temperature at reference values and tracking the minimum supply water temperature in order to find the temperature potential for the future DH systems. Both of the MPC controllers proved to have a better tracking effect for indoor air temperature and lower average supply temperatures compared to weather- compensated. The MPC controller 2 could further lower supply water temperature compared to the MPC controller 1 by tracking minimum supply water temperature in its objective function. The average supply water temperatures for the weather- compensated, the MPC controller1, and the MPC controller 2 were 52°C, 51°C and 50°C, respectively. The results showed that MPC has a great potential in the area of supply water temperature control of the district heating systems.
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Wahid, Abdul, et Naufal Syafiq Maro. « Multi Input Multi Output (MIMO) Control 2x2 at Vacuum Distillation Unit for LVGO, MVGO, and HVGO Production ». E3S Web of Conferences 67 (2018) : 03012. http://dx.doi.org/10.1051/e3sconf/20186703012.
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Currently, Indonesia is still experiencing a fuel deficit, so it is necessary to build a new oil refinery and a process optimization at an existing refinery. A vacuum distillation unit (VDU) is used to process the atmospheric residue products from crude distillation unit (CDU). A multivariable model predictive control (MMPC) is proposed to improve a control performance in VDU because of the interaction between variables in the unit. Therefore, it is necessary to find the variables that interact with each other. In this study only two variables are discussed. Set point (SP) and disturbance changes are used to test the control performance with integral of square error (ISE) as the indicator. The results are compared with the control performance of the PI controller and a single MPC. As a result, the feed flow rate and bottom-stage temperature are strongest interactions so that both are determined as controlled variables in MMPC. The control performance of MMPC is better than the PI controller and the single MPC with control performance improvement of 48% to the PI controller and 21% to MPC on for Feed Flow Rates, and 98% to the PI controller and 27% to MPC on Bottom Stage Temperature. While on disturbance changes the enhancement is 35% for the Bottom Stage Temperature.
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Wahid, Abdul, et Richi Adi. « MODELING AND CONTROL OF MULTIVARIABLE DISTILLATION COLUMN USING MODEL PREDICTIVE CONTROL USING UNISIM ». SINERGI 20, no 1 (1 février 2016) : 14. http://dx.doi.org/10.22441/sinergi.2016.1.003.
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Distillation columns are widely used in chemical industry as unit operation and required advance process control because it has multi input multi output (MIMO) or multi-variable system, which is hard to be controlled. Model predictive control (MPC) is one of alternative controller developed for MIMO system due to loops interaction to be controlled. This study aimed to obtain dynamic model of process control on a distillation column using MPC, and to get the optimum performance of MPC controller. Process control in distillation columns performed by simulating the dynamic models of distillation columns by UNISIM R390.1 software. The optimization process was carried out by tuning the MPC controller parameters such as sampling time (Ts = 1 – 240 s), prediction horizon (P = 1-400), and the control horizon (M=1-400). The comparison between the performance of MPC and PI controller is presented and Integral Absolut Error (IAE) was used as comparison parameter. The results indicate that the performance of MPC was better than PI controller for set point change 0.95 to 0.94 on distillate product composition using a modified model 1 with IAE 0.0584 for MPC controller and 0.0782 for PI controller.
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Kumavat, Mayur, et Sushil Thale. « Analysis of CSTR Temperature Control with PID, MPC & ; Hybrid MPC-PID Controller ». ITM Web of Conferences 44 (2022) : 01001. http://dx.doi.org/10.1051/itmconf/20224401001.
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This paper presents an analysis of the continuous stirred tank reactor (CSTR) temperature control with the Proportional-Integral-Derivative (PID) Controller, Model Predictive Controller (MPC) and Hybrid-Model Predictive Controller-Proportional Integral Derivative Controller (MPC-PID). It is the main goal of this project to find a suitable improvement strategy for the system’s stability and accuracy to be more stable. By creating a model, the control system is implemented for all the above mentioned control methods and so comparative analysis is carried out to find the best control method for CSTR. Simulation data inspector is used to compare the performance of different types of control systems: PID, MPC and MPC-PID. It has been observed that the hybrid MPC-PID has a more effective control action than a PID controller; with some tuning, the MPC controller can maintain the temperature within a reference or set point range. The control and simulation toolbox is used to construct the model predictive control method in LabVIEW platform. The performance of controllers is measured in terms of settling time, rise time and percentage of overshoot. Finally, a comparative overview of PID, MPC and Hybrid MPC-PID controllers on system performance is presented and discussed.
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Kümpel, Alexander, Phillip Stoffel et Dirk Müller. « Self-adjusting model predictive control for modular subsystems in HVAC systems ». Journal of Physics : Conference Series 2042, no 1 (1 novembre 2021) : 012037. http://dx.doi.org/10.1088/1742-6596/2042/1/012037.
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Abstract In order to reduce the energy consumption and CO2 emissions in the building sector, an efficient control strategy, such as model predictive control (MPC) is required. However, MPC is rarely applied in buildings since the implementation and modeling is complex, time consuming and costly. To bring MPC into practice, controllers and models are needed, that automatically adapt their behavior to the controlled system. In this work, such a self-adjusting MPC applicable to heating, ventilation and air-conditioning (HVAC) systems is developed. The MPC is based on a simple grey-box model that is able to cover the general dynamics of the considered subsystem. The controller adapts the model parameters online according to the past measurements of the controlled system using a moving horizon estimation. The developed self-adjusting MPC is applied to three heating coils in a simulation. Compared with a PID controller, the self-adjusting MPC is able to increase the control quality up to 10%, while no manual tuning is needed. Additionally, the model predictive approach is able to reduce the power consumption of the pump by 80%.
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Rezaee, Alireza. « Model predictive Controller for Mobile Robot ». Transactions on Environment and Electrical Engineering 2, no 2 (27 juin 2017) : 18. http://dx.doi.org/10.22149/teee.v2i2.96.
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This paper proposes a Model Predictive Controller (MPC) for control of a P2AT mobile robot. MPC refers to a group of controllers that employ a distinctly identical model of process to predict its future behavior over an extended prediction horizon. The design of a MPC is formulated as an optimal control problem. Then this problem is considered as linear quadratic equation (LQR) and is solved by making use of Ricatti equation. To show the effectiveness of the proposed method this controller is implemented on a real robot. The comparison between a PID controller, adaptive controller, and the MPC illustrates advantage of the designed controller and its ability for exact control of the robot on a specified guide path.
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Xu, Ying, Wentao Tang, Biyun Chen, Li Qiu et Rong Yang. « A Model Predictive Control with Preview-Follower Theory Algorithm for Trajectory Tracking Control in Autonomous Vehicles ». Symmetry 13, no 3 (26 février 2021) : 381. http://dx.doi.org/10.3390/sym13030381.
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Research on trajectory tracking is crucial for the development of autonomous vehicles. This paper presents a trajectory tracking scheme by utilizing model predictive control (MPC) and preview-follower theory (PFT), which includes a reference generation module and a MPC controller. The reference generation module could calculate reference lateral acceleration at the preview point by PFT to update state variables, and generate a reference yaw rate in each prediction point. Since the preview range is increased, PFT makes the calculation of yaw rate more accurate. Through physical constraints, the MPC controller can achieve the best tracking of the reference path. The MPC problem is formulated as a linear time-varying (LTV) MPC controller to achieve a predictive model from nonlinear vehicle dynamics to continuous online linearization. The MPC-PFT controller method performs well by increasing the effective length of the reference path. Compared with MPC and PFT controllers, the effectiveness and robustness of the proposed method are proved by simulations of two typical working conditions.
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Vrečko, D., N. Hvala et M. Stražar. « The application of model predictive control of ammonia nitrogen in an activated sludge process ». Water Science and Technology 64, no 5 (1 septembre 2011) : 1115–21. http://dx.doi.org/10.2166/wst.2011.477.
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In this paper a model predictive controller (MPC) for ammonia nitrogen is presented and evaluated in a real activated sludge process. A reduced nonlinear mathematical model based on mass balances is used to model the ammonia nitrogen in the activated sludge plant. An MPC algorithm that minimises only the control error at the end of the prediction interval is applied. The results of the ammonia MPC were compared with the results of the ammonia feedforward-PI and ammonia PI controllers from our previous study. The ammonia MPC and ammonia feedforward-PI controller give better results in terms of ammonia removal and aeration energy consumption than the ammonia PI controller because of the measurable disturbances used. On the other hand, with the ammonia MPC, comparable or even slightly poorer results than with the ammonia feedforward-PI controller are obtained. Further improvements to the MPC could be possible with an improved accuracy of the nonlinear reduced model of the ammonia nitrogen, more sophisticated control criteria used inside the controller and the extension of the problem from univariable ammonia to multivariable total nitrogen control.
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Yasmine Begum, A., et G. V. Marutheeswar. « Design of MPC for Superheated Steam Temperature Control in a Coal-fired Thermal Power Plant ». Indonesian Journal of Electrical Engineering and Computer Science 4, no 1 (1 octobre 2016) : 73. http://dx.doi.org/10.11591/ijeecs.v4.i1.pp73-82.
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<p>A superheater is a vital part of the steam generation process in the boiler-turbine system. Reliable control of temperature in the superheated steam temperature system is essential to guarantee efficiency and high load-following capability in the operation of coal-fired Thermal power plant. The PI and PID controllers are extensively used in cascade control of secondary superheated steam temperature process.The design and implementation of a Model Predictive Control (MPC) strategy for the superheated steam temperature regulation in a thermal power plant is presented. A FOPTD model is derived from the dynamic model of the superheater. This model is required by the MPC algorithm to calculate the future control inputs. A new MPC controller is designed and its performance is tested through simulation studies. Compared with the superheater steam temperature control using a conventional PID controller, the steam temperature controlled by the MPC controller is found to be more stable. The stable steam temperature leads to energy saving and efficient plant operation, as verified by the simulation results. </p>
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Hu, Dawei, Gangyan Li et Feng Deng. « Gain-Scheduled Model Predictive Control for a Commercial Vehicle Air Brake System ». Processes 9, no 5 (20 mai 2021) : 899. http://dx.doi.org/10.3390/pr9050899.
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This paper presents a control-oriented Linear Parameter-Varying (LPV) model for commercial vehicle air brake systems with the electro-pneumatic proportional valve based on the nonlinear mathematical model, a set of discrete-time linearized models at different target pressures with the q-Markov Cover system identification method. The scheduled parameters for the LPV model were the brake chamber pressure, which was controlled by the electro-pneumatic proportional valve. On the basis of the LPV model, a family of Model Predictive Control (MPC) controllers with a Kalman filter was designed at each operation point. Then, the gain-scheduled MPC was designed over the entire operating range with the switched strategy, which was validated by experimental data. Furthermore, compared with the PID controller, the performance of the system was improved with a gain-scheduled MPC controller.
Thèses sur le sujet "MPC controller"
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Hällerstam, Jonsson Linnea. « Fuel optimizing cruise controller with driveability ». Thesis, KTH, Optimeringslära och systemteori, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209680.
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This thesis work is based on a dynamic programming solution of a fuel optimizing cruise controller that was developed at Scania CV AB last year. Known data of the road ahead, mainly the slope, is used to continuously calculate the optimal torque and gear choices of a given moving vehicle for a certain horizon. The optimization calculations are based on fuel consumption and the vehicle's arrival time to the final destination. This report has been focused on achieving better "driveability" of the cruise controller while still maintaining the good fuel saving qualities that is already there. Simulation is used to evaluate the cruise controller on roads where the wanted data is known. The result is smaller speed variations on at road segments, which will improve a driver's impression of the cruise controller. The great fuel benefits of using roll-techniques in hilly areas is maintained from the previous implementation. The key to the optimal balance between these two behaviors is found using a method that limits the torque usage of the truck to a certain speed interval and then finds exception areas where the torque usage should be unlimited.Detta examensarbete är baserad på en dynamisk programmeringslösning av en bränsleoptimerande farthållare som utvecklades på Scania CV AB förra året. Känd data om den framförvarande vägen, så som lutningen, används för att beräkna optimalt drivmoment och växelval för ett givet fordon för en viss horizont. Optimeringsberäkningarna baseras på bränsleförbrukning och fordonets ankomsttid till målet. Denna rapport focuserar på att uppnå bättre "körbarhet" för farthållaren och samtidigt behålla de goda bränslebesparande egenskaper som farthållaren redan har. Simulering nyttjas för att analysera farthållaren på vägar där önskad data är känd. Resultatet är mindre hastighetsvariationer på platta vägar, vilket bör förbättra förarens uppfattning av farthållaren. De stora fördelar som kommer med användning av rull-tekniker på kuperade vägsträckor bevaras från den tidigare implementeringen. Nyckeln till optimal balans mellan dessa två körbeteenden är en metod som går ut på att begränsa fordonets momentanvändning till ett visst hastighetsinterval och sedan hitta undantagsområden där momentanvändning borde vara obegränsad.
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Claro, Érica Rejane Pereira. « Localização de canais afetando o desempenho de controladores preditivos baseados em modelos ». reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/149927.
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O escopo desta dissertação é o desenvolvimento de um método para detectar os modelos da matriz dinâmica que estejam degradando o desempenho de controladores preditivos baseados em modelos. O método proposto se baseia na análise de correlação cruzada entre o erro nominal do controlador em malha fechada e a uma estimativa da contribuição de cada canal para o cálculo da saída, filtrada pela função de sensibilidade do controlador. Esse método pode ser empregado na auditoria de controladores com variáveis controladas em setpoints e/ou com variáveis que operem entre faixas, como é usual de se encontrar na indústria. Esta dissertação apresenta os resultados da aplicação bem sucedida do método no sistema de quatro tanques (JOHANSSON, 2000), para o qual três cenários foram avaliados. No primeiro cenário, o método localizou corretamente discrepâncias de ganho e de dinâmica de modelos de um controlador preditivo baseado em modelos (Model-based Predictive Controller, ou controlador MPC). No segundo, o método foi utilizado para avaliar a influência de uma variável externa para melhorar o desempenho de um controlador afetado por distúrbios não medidos. No terceiro cenário, o método localizou canais com modelos nulos que deveriam ser incluídos na matriz de controle de um controlador MPC de estrutura descentralizada. Os resultados deste estudo de caso foram comparados com aqueles obtidos pelo método proposto por BADWE, GUDI e PATWARDHAN (2009), constatando-se que o método proposto é mais robusto que o método usado na comparação, não demandando ajustes de parâmetros por parte do usuário para fornecer bons resultados. A dissertação inclui também um estudo de caso da aplicação industrial do método na auditoria de desempenho de um controlador preditivo linear de estrutura descentralizada, com doze variáveis controladas, oito manipuladas e quatro distúrbios não medidos, aplicado a um sistema de fracionamento de propeno e propano em uma indústria petroquímica. A auditoria permitiu reduzir o escopo de revisão do controlador a dezenove canais da matriz, sendo que quatorze destes correspondiam a canais com modelos nulos que deveriam ser incluídos na matriz. A eficácia do método foi comprovada repetindo-se a avaliação da qualidade de modelo para todas as variáveis controladas.The scope of this dissertation is the development of a method to detect the models of the dynamic matrix that are affecting the performance of model-based predictive controllers. The proposed method is based on the cross correlation analysis between the nominal controller error and an estimate of the contribution of each channel to the controller output, filtered by the controller nominal sensitivity function. The method can be used in the performance assessment of controllers employing variables controlled at the setpoint and/or those controlled within ranges. This dissertation presents the results of the successful application of the method to the quadruple-tank process (JOHANSSON, 2000), for which three scenarios were evaluated. In the first scenario, the method correctly located gain and dynamic mismatches on a model-based predictive controller (MPC controller). In the second one, the method was used to evaluate the influence of an external variable to improve the performance of a controller affected by unmeasured disturbances. In the third scenario, the method located null models that should be included in the dynamic matrix of a decentralized MPC controller. The results of the three scenarios were compared with the ones obtained through the method proposed by BADWE, GUDI e PATWARDHAN (2009). The proposed method was considered more robust than the reference one for not requiring parameters estimation performed by the user to provide good results. This dissertation also includes a case study about the application of the method on the performance assessment of an industrial linear predictive controller of decentralized structure. The controller has twelve controlled variables, eight manipulated variables, and four unmeasured disturbances and is applied to a propylene-propane fractionation system of a petrochemical industry. The performance assessment allowed reducing the scope of the controller revision to nineteen channels of the models matrix, fourteen of which were null models that should be included in the controller. The efficacy of the proposed method was confirmed by repeating the model quality evaluation for all the controlled variables.
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Mattsson, Mathias, et Rasmus Mehler. « Optimal Vehicle Speed Control Using a Model Predictive Controller for an Overactuated Vehicle ». Thesis, Linköpings universitet, Fordonssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119480.
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To control the speed of an overactuated vehicle there may be many possible ways to use the actuators of the car achieving the same outcome. The actuators in an ordinary car is a combustion engine and a friction brake. In some cases it is trivial how to coordinate actuators for the optimal result, but in many cases it is not. The goal with the thesis is to investigate if it is possible to achieve the same or improved performance with a more sophisticated control structure than today's, using a model predictive controller. A model predictive controller combines the possibility to predict the outcome through an open-loop controller with the stability of a closed loop controller and gives the optimal solution for a finite horizon optimization problem. A simple model of the longitudinal dynamics of a car is developed and used in the model predictive controller framework. This is then used in simulations and in a real car. It is shown that it is possible to replace the current controller structure with a model predictive controller, but there are advantages and disadvantages with the new control structure.
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Rabbani, Ronak. « Developing and deploying enhanced algorithms to enable operational stability control systems with embedded high voltage DC links ». Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/12293.
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The increasing penetration of renewable energy resources within the Great Britain (GB) transmission system has created much greater variability of power flows within the transmission network. Consequently, modern transmission networks are presented with an ever increasing range of operating conditions. As a result, decision making in the Electricity National Control Centre (ENCC) of the GB electrical power transmission system is becoming more complex and control room actions are required for reducing timescales in the future so as to enable optimum operation of the system. To maximise utilisation of the electricity transmission system there is a requirement for fast transient and dynamic stability control. In this regard, GB electrical power transmissions system reinforcement using new technology, such as High Voltage Direct Current (HVDC) links and Thyristor-Controlled Series Compensation (TCSC), is planned to come into operation. The research aim of this PhD thesis is to fully investigate the effects of HVDC lines on power system small-disturbance stability in the presence of operational uncertainties. The main research outcome is the comprehensive probabilistic assessment of the stability improvements that can be achieved through the use of supplementary damping control when applied to HVDC systems. In this thesis, two control schemes for small-signal dynamic stability enhancement of an embedded HVDC link are proposed: Modal Linear Quadratic Gaussian (MLQG) controller and Model Predictive Controller (MPC). Following these studies, probabilistic methodologies are developed in order to test of the robustness of HVDC based damping controllers, which involves using classification techniques to identify possible mitigation options for power system operators. The Monte Carlo (MC) and Point Estimated Method (PEM) are developed in order to identify the statistical distributions of critical modes of a power system in the presence of uncertainties. In addition, eigenvalue sensitivity analysis is devised and demonstrated to ensure accurate results when the PEM is used with test systems. Finally, the concepts and techniques introduced in the thesis are combined to investigate robustness for the widely adopted MLQG controller and the recently introduced MPC, which are designed as the supplementary controls of an embedded HVDC link for damping inter-area oscillations. Power system controllers are designed using a linearised model of the system and tuned for a nominal operating point. The assumption is made that the system will be operating within an acceptable proximity range of its nominal operating condition and that the uncertainty created by changes within each operating point can possibly have an adverse effect on the controller’s performance.
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Bangalore, Narendranath Rao Amith Kaushal. « Online Message Delay Prediction for Model Predictive Control over Controller Area Network ». Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78626.
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Today's Cyber-Physical Systems (CPS) are typically distributed over several computing nodes communicating by way of shared buses such as Controller Area Network (CAN). Their control performance gets degraded due to variable delays (jitters) incurred by messages on the shared CAN bus due to contention and network overhead. This work presents a novel online delay prediction approach that predicts the message delay at runtime based on real-time traffic information on CAN. It leverages the proposed method to improve control quality, by compensating for the message delay using the Model Predictive Control (MPC) algorithm in designing the controller. By simulating an automotive Cruise Control system and a DC Motor plant in a CAN environment, it goes on to demonstrate that the delay prediction is accurate, and that the MPC design which takes the message delay into consideration, performs considerably better. It also implements the proposed method on an 8-bit 16MHz ATmega328P microcontroller and measures the execution time overhead. The results clearly indicate that the method is computationally feasible for online usage.Master of Science
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Holma, Erik. « Data Requirements for a Look-Ahead System ». Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10197.
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Look ahead cruise control deals with the concept of using recorded topographic road data combined with a GPS to control vehicle speed. The purpose of this is to save fuel without a change in travel time for a given road. This thesis explores the sensitivity of different disturbances for look ahead systems. Two different systems are investigated, one using a simple precalculated speed trajectory without feedback and the second based upon a model predictive control scheme with dynamic programming as optimizing algorithm.
Defect input data like bad positioning, disturbed angle data, faults in mass estimation and wrong wheel radius are discussed in this thesis. Also some investigations of errors in the environmental model for the systems are done. Simulations over real road profiles with two different types of quantization of the road slope data are done. Results from quantization of the angle data in the system are important since quantization will be unavoidable in an implementation of a topographic road map.
The results from the simulations shows that disturbance of the fictive road profiles used results in quite large deviations from the optimal case. For the recorded real road sections however the differences are close to zero. Finally conclusions of how large deviations from real world data a look ahead system can tolerate are drawn.
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Carlborg, Hampus, et Henrik Iredahl. « Modeling and Temperature Control of an Industrial Furnace ». Thesis, Linköpings universitet, Reglerteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129617.
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A linear model of an annealing furnace is developed using a black-box system identification approach, and used when testing three different control strategies to improve temperature control. The purpose of the investigation was to see if it was possible to improve the temperature control while at the same time decrease the switching frequency of the burners. This will lead to a more efficient process as well as less maintenance, which has both economic and environmental benefits. The estimated model has been used to simulate the furnace with both the existing controller and possible new controllers such as a split range controller and a model predictive controller (MPC). A split range controller is a control strategy which can be used when more than one control signal affect the output signal, and the control signals have different range. The main advantage with MPC is that it can take limitations and constraints into account for the controlled process, and with the use of integer programming, explicitly account for the discrete switching behavior of the burners. In simulation both new controllers succeed in decreasing the switching and the MPC also improved the temperature control. This suggest that the control of the furnace can be improved by implementing one of the evaluated controllers.
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Mörhed, Joakim, et Filip Östman. « Automatic Parking and Path Following Control for a Heavy-Duty Vehicle ». Thesis, Linköpings universitet, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-144496.
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The interest in autonomous vehicles has never been higher and there are several components that need to function for a vehicle to be fully autonomous; one of which is the ability to perform a parking at the end of a mission. The objective of this thesis work is to develop and implement an automatic parking system (APS) for a heavy-duty vehicle (HDV). A delimitation in this thesis work is that the parking lot has a known structure and the HDV is a truck without any trailer and access to more computational power and sensors than today's commercial trucks. An automatic system for searching the parking lot has been developed which updates an occupancy grid map (OGM) based on measurements from GPS and LIDAR sensors mounted on the truck. Based on the OGM and the known structure of the parking lot, the state of the parking spots is determined and a path can be computed between the current and desired position. Based on a kinematic model of the HDV, a gain-scheduled linear quadratic (LQ) controller with feedforward action is developed. The controller's objective is to stabilize the lateral error dynamics of the system around a precomputed path. The LQ controller explicitly takes into account that there exist an input delay in the system. Due to minor complications with the precomputed path the LQ controller causes the steering wheel turn too rapidly which makes the backup driver nervous. To limit these rapid changes of the steering wheel a controller based on model predictive control (MPC) is developed with the goal of making the steering wheel behave more human-like. A constraint for maximum allowed changes of the controller output is added to the MPC formulation as well as physical restrictions and the resulting MPC controller is smoother and more human-like, but due to computational limitations the controller turns out less effective than desired. Development and testing of the two controllers are evaluated in three different environments of varying complexity; the simplest simulation environment contains a basic vehicle model and serves as a proof of concept environment, the second simulation environment uses a more realistic vehicle model and finally the controllers are evaluated on a full-scale HDV. Finally, system tests of the APS are performed and the HDV successfully parks with the LQ controller as well as the MPC controller. The concept of a self-parking HDV has been demonstrated even though more tuning and development needs to be done before the proposed APS can be used in a commercial HDV.
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Menighed, Kamel. « Commandes coopératives embarquées et tolérantes aux défauts ». Phd thesis, Université Henri Poincaré - Nancy I, 2010. http://tel.archives-ouvertes.fr/tel-00545412.
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Le travail présenté dans ce mémoire de thèse porte sur la tolérance aux défauts dans le cas des systèmes linéaires. Les moyens de communication numériques sont utilisés dans le cadre de la mise en oeuvre d'une architecture de commande tolérante aux défauts pour des systèmes complexes. Une coopération entre les modules de commande/diagnostic assure la tolérance à certains types de défauts qui affectent le système. La commande des systèmes est traditionnellement réalisée à partir d'un calculateur central qui collecte l'ensemble des informations relevées sur le procédé, puis les traite pour élaborer un ensemble de commande qui est appliqué au procédé. Avec le développement des systèmes commandés en réseaux (Networked Control System) et des systèmes embarqués, l'architecture des systèmes s'oriente vers une distribution des algorithmes de commande et de diagnostic. On se propose d'aborder le problème de la conception des stratégies de distribution de diagnostic/commande et de coopération des tâches de commande entre les sous-contrôleurs associés à chaque sous-système qui composent le système complexe et de prendre en compte les défauts des actionneurs et de capteurs affectant les sous-systèmes. Il s'agit alors d'élaborer une stratégie de commande coopérative visant à compenser les effets des défauts affectant le système. Les commandes locales sont des commandes prédictives à base de modèle (MPC : Model Predictive Control). Une analyse de stabilité a été faite en prenant en considération la défaillance du réseau de communication.
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Menighed, Kamel. « Commandes coopératives embarquées et tolérantes aux défauts ». Electronic Thesis or Diss., Nancy 1, 2010. http://www.theses.fr/2010NAN10071.
Texte intégralRésumé :
Le travail présenté dans ce mémoire de thèse porte sur la tolérance aux défauts dans le cas des systèmes linéaires. Les moyens de communication numériques sont utilisés dans le cadre de la mise en oeuvre d'une architecture de commande tolérante aux défauts pour des systèmes complexes. Une coopération entre les modules de commande/diagnostic assure la tolérance à certains types de défauts qui affectent le système. La commande des systèmes est traditionnellement réalisée à partir d'un calculateur central qui collecte l'ensemble des informations relevées sur le procédé, puis les traite pour élaborer un ensemble de commande qui est appliqué au procédé. Avec le développement des systèmes commandés en réseaux (Networked Control System) et des systèmes embarqués, l'architecture des systèmes s'oriente vers une distribution des algorithmes de commande et de diagnostic. On se propose d'aborder le problème de la conception des stratégies de distribution de diagnostic/commande et de coopération des tâches de commande entre les sous-contrôleurs associés à chaque sous-système qui composent le système complexe et de prendre en compte les défauts des actionneurs et de capteurs affectant les sous-systèmes. Il s'agit alors d'élaborer une stratégie de commande coopérative visant à compenser les effets des défauts affectant le système. Les commandes locales sont des commandes prédictives à base de modèle (MPC: Model Predictive Control). Une analyse de stabilité a été faite en prenant en considération la défaillance du réseau de communicationThe work presented in this memory of thesis focuses on fault tolerance in the case of linear systems. Digital communication tools are used in the context of the implementation of an architecture for fault tolerant control of complex systems. A cooperation between the control/diagnosis blocks ensures the tolerance to certain types of faults which affect the system. Control systems is traditionally carried out starting from a central computer that collects all information gathered on the process. Then, these information are treated in order to develop a set of command which is applied to the process. Thanks to the development of the Networked System Control and embedded systems, systems architecture is oriented towards a distributed control and diagnostic algorithms. One proposes to address the problem of designing distribution strategies for diagnosis/control and control tasks cooperation between sub-controllers associated at each subsystem comprising the complex system and to take into account the faults on the actuators and sensors that affect the subsystems. Then a cooperative control strategy is proposed. It aims at compensating the effects of the faults affecting the system. Local controls are based on Model Predictive Control (MPC). An analysis of stability was made taking into account the failure of the communication network
Livres sur le sujet "MPC controller"
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Efheij, Hafed. Modello di controllo predittivo e controllore PID in sistema in tempo reale : Progettazione, implementazione e confronto di controllori MPC e PID nel ... di processo in tempo reale. Edizioni Sapienza, 2020.
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Nelson, Taylor. KSZ8841-PMQL - Single-Port Ethernet MAC Controller with PCI Interface. Microchip Technology Incorporated, 2019.
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Nelson, Taylor. KSZ8841-16M/-32M - Single-Port Ethernet MAC Controller with Non-PCI Interface. Microchip Technology Incorporated, 2019.
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Tyndall, Alan, et Jacob M. van Laar. Stem cell therapies. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199642489.003.0085_update_003.
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Since the start of the international project in 1997, over 2000 patients have received a haematopoietic stem cell transplant (HSCT), mostly autologous, as treatment for a severe autoimmune disease, with overall 85% 5-year survival and 43% progression-free survival. Around 30% of patients in all disease subgroups had a complete response, often durable despite full immune reconstitution. In many cases, e.g. systemic sclerosis, morphological improvement such as reduction of skin collagen and normalization of microvasculature was documented, beyond any predicted known effects of intense immunosuppression alone. It is hoped that the results of the three running large prospective randomized controlled trials will allow modification of the protocols to reduce the high transplant-related mortality which relates to regimen intensity, age of patient, and comorbidity. Multipotent mesenchymal stromal cells (MSC) have been recently tested in various autoimmune diseases, exploiting their immune modulating properties and apparent low acute toxicity. MSC display immune privilege in that the patient requires no immunosuppression prior to allogeneic MSC infusion. Despite encouraging many small phase I/II studies, only 2 prospective controlled trials which achieved their primary endpoints have been published.
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Dondiego, Karen. LAN7430/LAN7431 PCIe to Gigabit Ethernet Controller with Integrated Ethernet PHY / MAC Data Sheet. Microchip Technology Incorporated, 2018.
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Otruba, Kathy. LAN7430/LAN7431 PCIe to Gigabit Ethernet Controller with Integrated Ethernet PHY / MAC - Product Brief. Microchip Technology Incorporated, 2017.
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Otruba, Kathy. LAN7430/LAN7431 PCIe to Gigabit Ethernet Controller with Integrated Ethernet PHY / MAC - Data Sheet. Microchip Technology Incorporated, 2018.
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Otruba, Kathy. LAN7430/LAN7431 Low Power PCIe to Gigabit Ethernet Controller with Integrated MAC / PHY - Data Sheet. Microchip Technology Incorporated, 2019.
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Otruba, Kathy. LAN7430/LAN7431 Low Power PCIe to Gigabit Ethernet Controller with Integrated MAC / PHY - Data Sheet. Microchip Technology Incorporated, 2019.
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Tanabe, Dorothy. KSZ8851-16MLL - Single-Port Ethernet MAC Controller with 8-Bit or 16-Bit Non-PCI Interface. Microchip Technology Incorporated, 2017.
Trouver le texte intégralChapitres de livres sur le sujet "MPC controller"
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Mehmood, Usama, Shouvik Roy, Radu Grosu, Scott A. Smolka, Scott D. Stoller et Ashish Tiwari. « Neural Flocking : MPC-Based Supervised Learning of Flocking Controllers ». Dans Lecture Notes in Computer Science, 1–16. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45231-5_1.
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AbstractWe show how a symmetric and fully distributed flocking controller can be synthesized using Deep Learning from a centralized flocking controller. Our approach is based on Supervised Learning, with the centralized controller providing the training data, in the form of trajectories of state-action pairs. We use Model Predictive Control (MPC) for the centralized controller, an approach that we have successfully demonstrated on flocking problems. MPC-based flocking controllers are high-performing but also computationally expensive. By learning a symmetric and distributed neural flocking controller from a centralized MPC-based one, we achieve the best of both worlds: the neural controllers have high performance (on par with the MPC controllers) and high efficiency. Our experimental results demonstrate the sophisticated nature of the distributed controllers we learn. In particular, the neural controllers are capable of achieving myriad flocking-oriented control objectives, including flocking formation, collision avoidance, obstacle avoidance, predator avoidance, and target seeking. Moreover, they generalize the behavior seen in the training data to achieve these objectives in a significantly broader range of scenarios. In terms of verification of our neural flocking controller, we use a form of statistical model checking to compute confidence intervals for its convergence rate and time to convergence.
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Qian, Hong, Wei-xiao Jin, Jian-bo Luo et Min-rui Fei. « Research on Multivariable MPC Controller Design and Simulation of Interconnected Power Systems LFC ». Dans Communications in Computer and Information Science, 97–108. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-45286-8_11.
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Klaučo, Martin, et Michal Kvasnica. « Thermostatically Controlled Indoor Temperature ». Dans MPC-Based Reference Governors, 103–12. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-17405-7_9.
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Klaučo, Martin, et Michal Kvasnica. « Inner Loops with PID Controllers ». Dans MPC-Based Reference Governors, 35–43. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-17405-7_4.
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Jonath, Lucas, Jörg Luderich, Jonas Brezina, Ana Maria Gonzalez Degetau et Selim Karaoglu. « Improving the Thermal Behavior of High-Speed Spindles Through the Use of an Active Controlled Heat Pipe System ». Dans Lecture Notes in Production Engineering, 203–18. Cham : Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34486-2_16.
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AbstractThe thermo-elastic behavior of high-speed spindles has a significant influence on the machine accuracy. The Tool Center Point (TCP) changes continuously, not only due to the different temperature levels and energy inputs during warm-up, full-load and part-load operation, but also during interruptions for workpiece or tool changes. In this paper a heat pipe based tempering system is presented to control the spindle temperature and thus to keep the TCP displacement at a constant level, regardless of speed and load. As effective passive heat transfer components, heat pipes can be used not only to cool the system but also to insert heat into it. This capability of reversing the heat flow enables a high controllability of the temperature field in a bidirectional way and allows innovative capabilities of using advanced control algorithms. This paper describes the overall heat pipe concept and focuses on its potential as a key element for dynamic temperature control systems. Experimental results prove the feasibility of the concept with a simple on-off controller, achieving the reduction of the TCP displacement variation of a 2.2 kW spindle by 62% of its original value. The potential of the tempering concept forms the base for the deployment of various advanced control systems, such as Model-based Predictive Control (MPC), Fuzzy or Reinforcement Learning.
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Freeman, Adam. « Controller Extensibility ». Dans Pro ASP.NET MVC 5, 529–58. Berkeley, CA : Apress, 2013. http://dx.doi.org/10.1007/978-1-4302-6530-6_19.
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Freeman, Adam. « Controller Extensibility ». Dans Pro ASP.NET MVC 4, 455–83. Berkeley, CA : Apress, 2012. http://dx.doi.org/10.1007/978-1-4302-4237-6_17.
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Klaučo, Martin, et Michal Kvasnica. « Inner Loops with Relay-Based Controllers ». Dans MPC-Based Reference Governors, 45–52. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-17405-7_5.
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Paz, José Rolando Guay. « Controllers ». Dans Beginning ASP.NET MVC 4, 39–46. Berkeley, CA : Apress, 2013. http://dx.doi.org/10.1007/978-1-4302-5753-0_4.
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Klaučo, Martin, et Michal Kvasnica. « Inner Loops with Model Predictive Control Controllers ». Dans MPC-Based Reference Governors, 53–68. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-17405-7_6.
Texte intégralActes de conférences sur le sujet "MPC controller"
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Masdoua, Yanis, Moussa Boukhnifer et Kondo H. Adjallah. « Building Energy Optimization with MPC Controller ». Dans 2021 25th International Conference on System Theory, Control and Computing (ICSTCC). IEEE, 2021. http://dx.doi.org/10.1109/icstcc52150.2021.9607246.
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Piper, Matthew, Pranav Bhounsule et Krystel K. Castillo-Villar. « How to Beat Flappy Bird : A Mixed-Integer Model Predictive Control Approach ». Dans ASME 2017 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/dscc2017-5285.
Texte intégralRésumé :
Flappy Bird is a mobile game that involves tapping the screen to navigate a bird through a gap between pairs of vertical pipes. When the bird passes through the gap, the score increments by one and the game ends when the bird hits the floor or a pipe. Surprisingly, Flappy Bird is a very difficult game and scores in single digits are not uncommon even after extensive practice. In this paper, we create three controllers to play the game autonomously. The controllers are: (1) a manually tuned controller that flaps the bird based on a vertical set point condition; (2) an optimization-based controller that plans and executes an optimal path between consecutive tubes; (3) a model-based predictive controller (MPC). Our results showed that on average, the optimization-based controller scored highest, followed closely by the MPC, while the manually tuned controller scored the least. A key insight was that choosing a planning horizon slightly beyond consecutive tubes was critical for achieving high scores. The average computation time per iteration for the MPC was half that of optimization-based controller but the worst case time (maximum time) per iteration for the MPC was thrice that of optimization-based controller. The success of the optimization-based controller was due to the intuitive tuning of the terminal position and velocity constraints while for the MPC the important parameters were the prediction and control horizon. The MPC was straightforward to tune compared to the other two controllers. Our conclusion is that MPC provides the best compromise between performance and computation speed without requiring elaborate tuning.
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R, Shreyas, Andrew Bradley et Gordana Collier. « MPC Controller for Autonomous Formula Student Vehicle ». Dans WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States : SAE International, 2020. http://dx.doi.org/10.4271/2020-01-0089.
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Raman, Naren Srivaths, Karthikeya Devaprasad et Prabir Barooah. « MPC-Based Building Climate Controller Incorporating Humidity ». Dans 2019 American Control Conference (ACC). IEEE, 2019. http://dx.doi.org/10.23919/acc.2019.8814615.
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Jankowski, Robert, Paweł D. Doman´ski et Konrad S´wirski. « Optimization of Coal Mill Using an MPC Type Controller ». Dans ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42299.
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The article presents the question of optimization of a ventilation coal mill on the basis of a predictive optimizing controller with a receding horizon, which is an extension of the standard linear MPC (Model Predictive Control) type controllers. The controller has been realized in a digital version operating with a certain sampling period dependent upon the process dynamics. All calculations of the control rules are performed in one cycle which enables the controller to operate in the running mode. On the basis of a right optimization procedure the controller regulates the correction of settings, which are introduced to classic control structures in a fuzzy control system. The non-linear process model, implemented in the controller, is based on the basis of fuzzy neural networks. This structure enables to design, learn and tune NARMAX type models (Nonlinear Auto Regressive Moving Average with auXiliary input) [1]. The process model uses fuzzy rules, where fuzzy rules figure on the side, which helps to avoid sharp switching between them. The consequences of the rules take the form of differential equations of the linear ARX type models. The use of neural networks ensures a fast and efficient implementation and effective learning and tuning. The problem of control is based in on a periodically performed optimization of the performance index, defined on the basis of the assumed project goals. The aim of the controller operation is to eliminate undesired events occurring during mill operation. Such events are: instability of temperature value of air-dust mix after the mill, excessive fluctuation of air temperature before the mill and positioning of primary and secondary air dampers outside the control range. These goals are realized through appropriate control of the primary air damper and revolving speed of the mill. The implementation carried out of the described controller in a digital automatic control system on 8 ventilation mills of a 360 MW brown coal fired boiler. This article presents the results obtained and a carried out analysis.
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Larosa, Luca, Alberto Traverso, Mario L. Ferrari et Valentina Zaccaria. « Pressurized SOFC Hybrid Systems : Control System Study and Experimental Verification ». Dans ASME Turbo Expo 2014 : Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25246.
Texte intégralRésumé :
In this paper two different advanced control approaches for a pressurized SOFC hybrid system are investigated and compared against traditional proportional–integral–derivative (PID). Both advanced control methods use model predictive control (MPC): in the first case, the MPC has direct access to the plant manipulated variables, in the second case the MPC operates on the setpoints of PIDs which control the plant. In the second approach the idea is to use MPC at the highest level of the plant control system to optimize the performance of bottoming PIDs, retaining system stability and operator confidence. Two MIMO (multi-input multi-output) controllers were obtained: fuel cell power and cathode inlet temperature are the controlled variables; fuel cell by-pass flow, current and fuel mass flow rate (the utilization factor kept constant) are the manipulated variables. The two advanced control methods were tested and compared against the conventional PID approach using a SOFC hybrid system model. Then, the MPC controller was implemented in the hybrid system emulator test rig developed by the Thermochemical Power Group (TPG) at the University of Genoa. Experimental tests were carried out to compare MPC against classic PID method: load following tests were carried out. Ramping the fuel cell load from 100% to 80% and back, keeping constant the target of the cathode inlet temperature, the MPC controller was able to reduce the mismatch between the actual and the target values of the cathode inlet temperature from 7 K maximum of the PID controller to 3 K maximum, showing more stable behavior in general.
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Kozak, Stefan, et Anton Pytel. « MPC controller as a service in IoT architecture ». Dans 2018 Cybernetics & Informatics (K&I). IEEE, 2018. http://dx.doi.org/10.1109/cyberi.2018.8337550.
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Minhajullah, Syed, Sami El Ferik, Mustafa Elshafei et M. A. Habib. « MPC-based controller for augmented boiler-NOx model ». Dans 2012 IEEE 9th International Multi-Conference on Systems, Signals and Devices (SSD). IEEE, 2012. http://dx.doi.org/10.1109/ssd.2012.6197924.
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Ganga, G., et Meher Madhu Dharmana. « MPC controller for trajectory tracking control of quadcopter ». Dans 2017 International Conference on Circuit ,Power and Computing Technologies (ICCPCT). IEEE, 2017. http://dx.doi.org/10.1109/iccpct.2017.8074380.
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Cheong, Seunggyun. « A strategy of replacement of a PI controller with an MPC controller ». Dans 2016 American Control Conference (ACC). IEEE, 2016. http://dx.doi.org/10.1109/acc.2016.7525148.
Texte intégralRapports d'organisations sur le sujet "MPC controller"
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Stute, Petra, Susanne Theis, Argy Kolokythas, Marc von Gernler, Astrid Eicher, Elenva Pavicic, Linus Walker et Sabrina Baumgartner. Systematic review on the influence of progestogens on the endometrium. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, juin 2023. http://dx.doi.org/10.37766/inplasy2023.6.0028.
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Review question / Objective: The objective of this systematic review is to summarize published data from randomized controlled trials regarding the influence of a combined menopausal hormone therapy on the endometrium with specific focus on endometrial hyperplasia and endometrial cancer incidence. Eligibility criteria: The following progestagens will be investigated: Norethisterone (acetate) = NET(A), Dienogest = DNG, Dydrogesterone = DYD, Micronized Progesterone = MP, Drospirenone = DRSP, Levonorgestrel = LNG, Cyproterone acetate = CPA, Medroxyprogesterone acetate = MPA, Chlormadinone acetate = CMAExogenously administered on oral, transdermal or vaginal route; duration of study at least 3 months; in humans.
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Zhu, Shixin, Heng Gao et Gang Chen. Efficacy and Safety of PRC-063 for Attention-deficit/hyperactivity disorder : A systematic review and meta-analysis from randomized controlled trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, décembre 2022. http://dx.doi.org/10.37766/inplasy2022.12.0073.
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Review question / Objective: We conducted a systematic review and meta-analysis from randomized controlled trials to evaluate the efficacy and safety of PRC-063 for Attention-deficit/hyperactivity disorder. Condition being studied: Attention-deficit/hyperactivity disorder (ADHD) is diagnosed with the core symptoms including inattention, hyperactivity and/or impulsivity.Current treatment options for ADHD include pharmacological treatment， behavioral therapy, and combination therapy of the two treatments above. Methylphenidate (MPH) and the extended-release formulation, as a first-line pharmacological treatment of ADHD, have been widely researched in the world.
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Alhasan, Ahmad, Brian Moon, Doug Steele, Hyung Lee et Abu Sufian. Chip Seal Quality Assurance Using Percent Embedment. Illinois Center for Transportation, décembre 2023. http://dx.doi.org/10.36501/0197-9191/23-029.
Texte intégralRésumé :
This study investigates the use of macrotexture as an indicator of the percent embedment (PE) of aggregate in a chip seal and ultimately, as a quality assurance tool for chip seals. The study included an extensive field- and controlled-testing program from 24 chip seal sections constructed in Illinois. Surface texture measurements were acquired using a high-speed texture profiler and a stationary laser texture device. The analysis showed that stationary texture measurements were more consistent and reliable for estimating PE and characterizing chip seals in the field. Moreover, the ground truth PE values were estimated using an image analysis algorithm implemented on side-view images of cores extracted in the field. The ground truth PE values were estimated using four approaches: the average elevation method, percent embedment of each aggregate method, the peak method, and the aggregate circumference method. The analysis showed that the correlations between the different PE estimation methods are relatively weak, indicating the various methods provide different information and may relate to different characteristics. The general regression models for PE values estimated using the average elevation method and the mean profile depth (MPD) acquired using laser texture scans and the average least dimension (ALD) yielded the highest R2 value of 0.50. The model showed a consistent decreasing trend between PE and MPD estimated using laser texture scans and side-view images. Moreover, the model matched the expected behavior that PE should reach 100% as MPD reaches 0. Finally, four models were recommended correlating PE estimated using the average elevation and each aggregate methods to the MPD (mm) estimated from laser texture scans and ALD (mm) estimated from side-view images.
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Botros, Geerligs et Given. L52187 Decompression Response of High-Pressure Natural Gas Pipelines Under Rupture or Blowdown Conditions. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), août 2004. http://dx.doi.org/10.55274/r0010394.
Texte intégralRésumé :
The Pipeline Research Council International, Inc. found that Scandpower has software that is capable of predicting the transient response of a pipeline segment transporting either conventional or enriched dense phase natural gas mixtures when subjected to a controlled blow down or an uncontrolled rupture event. Consequently PRCI expressed a desire to pursue an experimental work to provide the basis for evaluating the adequacy of the existing software and/or define further development if any. NOVA Research and Technology Corporation (NRTC) was awarded a contract to perform the experimental work and compare results with prediction by the OLGA 2000 software. The existing NPS 2 stainless steel decompression tube test rig at TCPL Gas Dynamic Test Facility (GDTF) in Didsbury, Alberta, Canada, has been expanded specifically for this project. The initial length of 30 meters was extended to 172 meters in order to simulate a longer length to diameter (L/D) ratio. Two sets of tests were conducted: one to simulate pipeline rupture and another to simulate controlled blowdown. Rupture was simulated by a rupture disc located at one end of the tube, while blowdown was affected by a typical blowdown stack and a reduce-bore ball valve. The test scope included three gas mixtures (conventional, medium rich and rich) and three initial pressures: 10, 14 and 20 MPa.
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Pesis, Edna, Elizabeth J. Mitcham, Susan E. Ebeler et Amnon Lers. Application of Pre-storage Short Anaerobiosis to Alleviate Superficial Scald and Bitter Pit in Granny Smith Apples. United States Department of Agriculture, janvier 2013. http://dx.doi.org/10.32747/2013.7593394.bard.
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There is increased demand for high quality fruit produced and marketed with reduced chemical inputs to minimize toxic effects on human health and the environment. Granny Smith (GS) apple quality is reduced by two major physiological disorders, superficial scald and bitter pit (BP). These disorders cause great loss to apple growers worldwide. Superficial scald is commonly controlled by chemical treatments, mainly the antioxidant diphenylamine (DPA) and/or the ethylene action inhibitor, 1-methylcyclopropene (1–MCP). Both chemicals are ineffective in controlling bitter pit incidence. We proposed to investigate the beneficial use of non-chemical, abiotic stress with low O2 (LO2) applied for 10d at 20°C on GS apple fruit. During the project we expanded the treatment to more apple cultivars, Golden Delicious (GD) and Starking Delicious (SD) and another pome fruit, the pear. Apple and pear have similar physiological disorders that develop during cold storage and we examined if the LO2 treatment would also be effective on pear. Application of 0.5% LO2 atmosphere for 10d at 20°C or 500ppb 1-MCP at 20°C prior to cold storage at 0°C, was effective in reducing superficial scald in GS apple. Moreover, LO2 pretreatment was also effective in reducing bitter pit (BP) development in California GS and Israeli GD and SD apples The BP symptoms in GS from California were much more prominent, so the effect of LO2 was more dramatic than the effect on the Israeli cvs. GD and SD, nevertheless the LO2 treatment showed the same trend in all cultivars in reducing BP. The LO2 and 1-MCP -treated fruit exhibited lower levels of ethylene, - farnesene and its oxidation product, 6-methyl-5-hepten-2-one (MHO), as determined by SPME/GC-MS analysis. In addition, LO2 pretreatment applied to California Bartlett or Israeli Spadona pears was effective in reducing superficial scald, senescent scald and internal breakdown after 4 m of cold storage at 0°C. For GS apple, low-temperature storage resulted in oxidative stress and chilling injury, caused by increased production of superoxide anions which in turn led to the generation of other dangerous reactive oxygen species (ROS). Using confocal laser-scanning microscopy and H2O2 measurements of apple peel, we observed ROS accumulation in control fruit, while negligible amounts were found in LO2 and 1-MCP treated fruit. Gene-expression levels of ROS-scavenging enzymes were induced by the various pretreatments: catalase was induced by LO2 treatment, whereas Mn superoxide dismutase was induced by 1-MCP treatment. We assume that LO2 and 1-MCP pretreated fruit remained healthier due to reduced production of ethylene and reactive oxygen substances, such as MHO, during cold storage. The LO2-treated apple exhibited greener peel and firmer fruit after 6 m of cold storage, and the fruit had high crispiness leading to high taste preference. In both pear cultivars, the LO2 treatment led to a reduction in internal breakdown and browning around the seed cavity. We tested the LO2 pre-storage treatment on a semi-commercial scale that would be applicable to a small organic grower by sealing the fruit within the plastic field bins. The treatment was most effective with a continuous flow of nitrogen through the bins; however, a single 6 hour flush of nitrogen was also fairly effective. In addition, we determined that it was very important to have the oxygen levels below 0.5% for approximately 10 days to achieve good scald control, not counting the time required to reduce the oxygen concentration. Our LO2 technology has been proven in this project to be effective in reducing several physiological disorders developed in pome fruit during cold storage. We hope that our non-chemical treatment which is friendly to the environment will be used in the near future for the organic apple and pear industry. The next step should be an analysis of the cost-benefits and commercial feasibility.
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Epel, Bernard L., Roger N. Beachy, A. Katz, G. Kotlinzky, M. Erlanger, A. Yahalom, M. Erlanger et J. Szecsi. Isolation and Characterization of Plasmodesmata Components by Association with Tobacco Mosaic Virus Movement Proteins Fused with the Green Fluorescent Protein from Aequorea victoria. United States Department of Agriculture, septembre 1999. http://dx.doi.org/10.32747/1999.7573996.bard.
Texte intégralRésumé :
The coordination and regulation of growth and development in multicellular organisms is dependent, in part, on the controlled short and long-distance transport of signaling molecule: In plants, symplastic communication is provided by trans-wall co-axial membranous tunnels termed plasmodesmata (Pd). Plant viruses spread cell-to-cell by altering Pd. This movement scenario necessitates a targeting mechanism that delivers the virus to a Pd and a transport mechanism to move the virion or viral nucleic acid through the Pd channel. The identity of host proteins with which MP interacts, the mechanism of the targeting of the MP to the Pd and biochemical information on how Pd are alter are questions which have been dealt with during this BARD project. The research objectives of the two labs were to continue their biochemical, cellular and molecular studies of Pd composition and function by employing infectious modified clones of TMV in which MP is fused with GFP. We examined Pd composition, and studied the intra- and intercellular targeting mechanism of MP during the infection cycle. Most of the goals we set for ourselves were met. The Israeli PI and collaborators (Oparka et al., 1999) demonstrated that Pd permeability is under developmental control, that Pd in sink tissues indiscriminately traffic proteins of sizes of up to 50 kDa and that during the sink to source transition there is a substantial decrease in Pd permeability. It was shown that companion cells in source phloem tissue export proteins which traffic in phloem and which unload in sink tissue and move cell to cell. The TAU group employing MP:GFP as a fluorescence probe for optimized the procedure for Pd isolation. At least two proteins kinases found to be associated with Pd isolated from source leaves of N. benthamiana, one being a calcium dependent protein kinase. A number of proteins were microsequenced and identified. Polyclonal antibodies were generated against proteins in a purified Pd fraction. A T-7 phage display library was created and used to "biopan" for Pd genes using these antibodies. Selected isolates are being sequenced. The TAU group also examined whether the subcellular targeting of MP:GFP was dependent on processes that occurred only in the presence of the virus or whether targeting was a property indigenous to MP. Mutant non-functional movement proteins were also employed to study partial reactions. Subcellular targeting and movement were shown to be properties indigenous to MP and that these processes do not require other viral elements. The data also suggest post-translational modification of MP is required before the MP can move cell to cell. The USA group monitored the development of the infection and local movement of TMV in N. benthamiana, using viral constructs expressing GFP either fused to the MP of TMV or expressing GFP as a free protein. The fusion protein and/or the free GFP were expressed from either the movement protein subgenomic promoter or from the subgenomic promoter of the coat protein. Observations supported the hypothesis that expression from the cp sgp is regulated differently than expression from the mp sgp (Szecsi et al., 1999). Using immunocytochemistry and electron microscopy, it was determined that paired wall-appressed bodies behind the leading edge of the fluorescent ring induced by TMV-(mp)-MP:GFP contain MP:GFP and the viral replicase. These data suggest that viral spread may be a consequence of the replication process. Observation point out that expression of proteins from the mp sgp is temporary regulated, and degradation of the proteins occurs rapidly or more slowly, depending on protein stability. It is suggested that the MP contains an external degradation signal that contributes to rapid degradation of the protein even if expressed from the constitutive cp sgp. Experiments conducted to determine whether the degradation of GFP and MP:GFP was regulated at the protein or RNA level, indicated that regulation was at the protein level. RNA accumulation in infected protoplast was not always in correlation with protein accumulation, indicating that other mechanisms together with RNA production determine the final intensity and stability of the fluorescent proteins.
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Li, Howell, Tom Platte, Jijo K. Mathew, W. Benjamin Smith, Enrique Saldivar-Carranza et Darcy M. Bullock. Using Connected Vehicle Data to Reassess Dilemma Zone Performance of Heavy Vehicles. Purdue University, 2020. http://dx.doi.org/10.5703/1288284317321.
Texte intégralRésumé :
The rate of fatalities at signalized intersections involving heavy vehicles is nearly five times higher than for passenger vehicles in the US. Previous studies in the US have found that heavy vehicles are twice as likely to violate a red light compared with passenger vehicles. Current technologies leverage setback detection to extend green time for a particular phase and are based upon typical deceleration rates for passenger cars. Furthermore, dilemma zone detectors are not effective when the max out time expires and forces the onset of yellow. This study proposes the use of connected vehicle (CV) technology to trigger force gap out (FGO) before a vehicle is expected to arrive within the dilemma zone limit at max out time. The method leverages position data from basic safety messages (BSMs) to map-match virtual waypoints located up to 1,050 ft in advance of the stop bar. For a 55 mph approach, field tests determined that using a 6 ft waypoint radius at 50 ft spacings would be sufficient to match 95% of BSM data within a 5% lag threshold of 0.59 s. The study estimates that FGOs reduce dilemma zone incursions by 34% for one approach and had no impact for the other. For both approaches, the total dilemma zone incursions decreased from 310 to 225. Although virtual waypoints were used for evaluating FGO, the study concludes by recommending that trajectory-based processing logic be incorporated into controllers for more robust support of dilemma zone and other emerging CV applications.
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Watkins, Chris B., Susan Lurie, Amnon Lers et Patricia L. Conklin. Involvement of Antioxidant Enzymes and Genes in the Resistance Mechanism to Postharvest Superficial Scald Development. United States Department of Agriculture, décembre 2004. http://dx.doi.org/10.32747/2004.7586539.bard.
Texte intégralRésumé :
The objective of this research project was to evaluate the involvement of antioxidant enzymes and genes in the resistance mechanism to postharvest superficial scald development using two primary systems: 1. Resistant and susceptible progenies of an apple cross between a scald resistant crab apple, ‘White Angel’ and a scald susceptible cultivar, ‘Rome Beauty’; 2. Heat-treatment of ‘Granny Smith’, which is known to reduce scald development in this cultivar. In 2002 we asked for, and received (October 14), permission to revise our initial objectives. The US side decided to expand their results to include further work using commercial cultivars. Also, both sides wanted to include an emphasis on the interaction between these antioxidant enzymes and the á-farnesene pathway, with the cooperation of a third party, Dr. Bruce Whitaker, USDA-ARS, Beltsville. Background: Superficial scald is a physiological storage disorder that causes damage to the skin of apple and pear fruit. It is currently controlled by use of an antioxidant, diphenylamine (DPA), applied postharvest by drenching or dips, but concern exists about such chemical usage especially as it also involves application of fungicides. As a result, there has been increased emphasis on understanding of the underlying mechanisms involved in disorder development. Our approach was to focus on the oxidative processes that occur during scald development, and specifically on using the two model systems described above to determine if the levels of specific antioxidants and/or antioxidant enzyme activities correlated with the presence/absence of scald. It was hoped that information about the role of antioxidant-defense mechanisms would lead to identification of candidate genes for future transgenic manipulation. Major conclusions, solutions, achievements: Collectively, our results highlight the complexity of superficial scald developmental processes. Studies involving comparisons of antioxidant enzyme activities in different crab apple selection, commercial cultivars, and in response to postharvest heat and 1-methylcyclopropene (1-MCP) treatments, show no simple direct relationships with antioxidant contents and susceptibility of fruit to scald development. However, a correlative relationship was found between POX activity or isoenzyme number and scald resistance in most of the studies. This relationship, if confirmed, could be exploited in breeding for scald resistance. In addition, our investigations with key genes in the á-farnesenebiosynthetic pathway, together with antioxidant processes, are being followed up by analysis of exposed and shaded sides of fruit of cultivars that show different degrees of scald control by 1-MCP. These data may further reveal productive areas for future research that will lead to long term control of the disorder. However, given the complexity of scald development, the greatest research need is the production of transgenic fruit with down-regulated genes involved in á- farnesene biosynthesis in order to test the currently popular hypothesis for scald development.
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Moss, Robb, Tristan Gebhart, David Frost et Christian Ledezma. Flow-Failure Case History of the Las Palmas, Chile, Tailings Dam. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, janvier 2019. http://dx.doi.org/10.55461/gvif2980.
Texte intégralRésumé :
This report documents the flow failure of the Las Palmas tailings dam that was induced by the 27 February 2010 Maule Chile M8.8 earthquake. The Las Palmas site is located in Central Chile in Region VII near the town of Talca. Construction of the tailings dam occurred between 1998 as part of a gold mining operation and was no longer in active use. The ground shaking from the earthquake induced liquefaction of the saturated tailings material and resulted in a flow failure that ran out upwards of 350 m, flowing downslope in two directions. This report is broken into three sections: A summary of the construction and flow failure of the Las Palmas tailings dam; Details on the field investigations at the site, including the 2010 GEER reconnaissance, 2011 litigation support [DICTUC 2012], and the recent PEER–NGL-funded 2017 investigation; and Back-analysis of the flow failure by Gebhart [2016] to estimate the residual strength. The goal of this work is to provide a “high-quality” flow-failure case history to augment the existing database. The existing database is composed of roughly thirty case histories of varying quality (e.g., Weber et al. [2015] and Kramer and Wang [2015]). Herein, the term “high-quality” means that the in situ measurements were made in a controlled and repeatable manner, and that the back-analysis of the residual strength was performed considering static and dynamic effects of the slide mass. The results from this research indicate that the median back-analyzed residual strength of the liquefied material is ~8.3 kPa (~173 psf) at a pre-earthquake vertical effective stress of 2 atm (~200 kpa or 4000 psf), which is correlated to a median SPT blow count of N1,60~2.5, a median CPT tip resistance of qc1~1.3 MPa, and a median shear-wave velocity of VS1~172 m/sec. The back analyzed residual strength has a nominal coefficient of variation of 5.5% determined using a sensitivity analysis.
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Law, Edward, Samuel Gan-Mor, Hazel Wetzstein et Dan Eisikowitch. Electrostatic Processes Underlying Natural and Mechanized Transfer of Pollen. United States Department of Agriculture, mai 1998. http://dx.doi.org/10.32747/1998.7613035.bard.
Texte intégralRésumé :
The project objective was to more fully understand how the motion of pollen grains may be controlled by electrostatic forces, and to develop a reliable mechanized pollination system based upon sound electrostatic and aerodynamic principles. Theoretical and experimental analyses and computer simulation methods which investigated electrostatic aspects of natural pollen transfer by insects found that: a) actively flying honeybees accumulate ~ 23 pC average charge (93 pC max.) which elevates their bodies to ~ 47 V likely by triboelectrification, inducing ~ 10 fC of opposite charge onto nearby pollen grains, and overcoming their typically 0.3-3.9 nN detachment force resulting in non-contact electrostatic pollen transfer across a 5 mm or greater air gap from anther-to-bee, thus providing a theoretical basis for earlier experimental observations and "buzz pollination" events; b) charge-relaxation characteristics measured for flower structural components (viz., 3 ns and 25 ns time constants, respectively, for the stigma-style vs. waxy petal surfaces) ensure them to be electrically appropriate targets for electrodeposition of charged pollen grains but not differing sufficiently to facilitate electrodynamic focusing onto the stigma; c) conventional electrostatic focusing beneficially concentrates pollen-deposition electric fields onto the pistill tip by 3-fold as compared to that onto underlying flower structures; and d) pollen viability is adequately maintained following exposure to particulate charging/management fields exceeding 2 MV/m. Laboratory- and field-scale processes/prototype machines for electrostatic application of pollen were successfully developed to dispense pollen in both a dry-powder phase and in a liquid-carried phase utilizing corona, triboelectric, and induction particulate-charging methods; pollen-charge levels attained (~ 1-10 mC/kg) provide pollen-deposition forces 10-, 77-, and 100-fold greater than gravity, respectively, for such charged pollen grains subjected to a 1 kV/cm electric field. Lab and field evaluations have documented charged vs. ukncharged pollen deposition to be significantly (a = 0.01-0.05) increased by 3.9-5.6 times. Orchard trials showed initial fruit set on branches individually treated with electrostatically applied pollen to typically increase up to ~ 2-fold vs. uncharged pollen applications; however, whole-tree applications have not significantly shown similar levels of benefit and corrective measures continue. Project results thus contribute important basic knowledge and applied electrostatics technology which will provide agriculture with alternative/supplemental mechanized pollination systems as tranditional pollen-transfer vectors are further endangered by natural and man-fade factors.