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1
Albassam, Bassam A. „Creating Nodes at Selected Locations in a Harmonically Excited Structure Using Feedback Control and Green’s Function“. Shock and Vibration 2019 (07.02.2019): 1–20. http://dx.doi.org/10.1155/2019/3261628.
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The paper deals with designing a control force to create nodal point(s) having zero displacements and/or zero slopes at selected locations in a harmonically excited vibrating structure. It is shown that the steady-state vibrations at desired points can be eliminated using feedback control forces. These control forces are constructed from displacement and/or velocity measurements using sensors located either at the control force position or at some other locations. Dynamic Green’s function is exploited to derive a simple and exact closed from expression for the control force. Under a certain condition, this control force can be generated using passive elements such as springs and dampers. Numerical examples demonstrate the applicability of the method in various cases.
2
Wang, Hao, Zhiying Lv, Hongyu Qin, Jianwei Yue und Jianwei Zhang. „Deformation Control Method of the Antislide Pile under Trapezoidal Load in the Zhangjiawan Landslide“. Advances in Civil Engineering 2020 (08.07.2020): 1–14. http://dx.doi.org/10.1155/2020/1405610.
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Antislide piles are set in the Zhangjiawan landslide area, where the general features of the bedrock below the slip surface include upper weak and lower hard strata. Based on a site investigation, the horizontal displacement of the antislide pile head is 14.8 cm, which is not conducive to the stability of the landslide. In the study, a displacement calculation method for the pile under trapezoidal load is proposed for a colluvial landslide controlling. Furthermore, factors affecting the deformation and internal forces of the pile were also studied. The results indicated that (1) when the embedded length of an antislide pile increases, the horizontal displacement on the pile and maximum absolute shear force decrease, while the bending moment of the pile exhibits opposite trends; (2) the relationship between maximum shear force and maximum bending moment is linear with increasing driving force of landslide; and (3) increase in the ratio of the driving force between the pile head and slip surface (q0/q1) steadily increases the horizontal displacement of the pile. The relationship between the distribution of the driving force (q0/q1) and the reasonable embedded length of a pile is a quadratic function, which can be used to determine the reasonable embedded length of a pile under the action of rectangular or triangular loads. It is very useful to use the above method to guide the design of antislide piles in similar areas.
3
Shon, Su-Deok, Alan S. K. Kwan und Seung-Jae Lee. „Displacement Control Technique of Pre-stressable Cable Structures by Force Method“. Journal of the Korean Association for Spatial Structures 11, Nr. 2 (15.06.2011): 139–49. http://dx.doi.org/10.9712/kass.2011.11.2.139.
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4
Ma, Niu Jing. „An Incremental Method for Cable Force Tuning of the Concrete Cable-Stayed Bridge Considering Cable-Girder Temperature Difference Effect“. Applied Mechanics and Materials 477-478 (Dezember 2013): 690–96. http://dx.doi.org/10.4028/www.scientific.net/amm.477-478.690.
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To ensure that the cable force tuning of Banfu No.2 bridge was carried out successfully, an incremental method for cable force tuning was presented, which took into account the cable-girder temperature difference. The cable forces were measured through frequency method. Before cable force tuning, all cable forces and temperatures of cables and girders were measured when the ambient temperature was stable, and these cable forces were taken as reference cable forces. During cable force tuning, the increment of cable force was regarded as the control quantity, while the displacement in the middle of main span was regarded as the verification quantity. After each stage, it was necessary to measure the temperatures of cables and girders and the displacement variation in the middle of the main span. To ensure the mechanical state of bridge was in control, all cable forces were measured after the 5th, 10th pairs of cables and all cables were tuned. In addition, the temperature-corrected cable forces were compared with the calculated ones, which showed the incremental method was not only accurate but also efficient.
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Wang, Hao, Peng Wang, Hongyu Qin, Jianwei Yue und Jianwei Zhang. „Method to Control the Deformation of Anti-Slide Piles in Zhenzilin Landslide“. Applied Sciences 10, Nr. 8 (19.04.2020): 2831. http://dx.doi.org/10.3390/app10082831.
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Anti-slide piles were used in the region of the Zhenzilin landslide in Sichuan, China. The horizontal displacement of these piles exceeds specifications. Deterioration in bedrock properties may cause deformation, thereby causing landslide destabilization. An approach was developed for the analysis of anti-slide pile in two bedrocks with different strengths below the slip surface. A relationship has been established between the modulus of subgrade reaction of the first weak bedrock and reasonable embedded length for landfill slopes with strata of various strengths. Furthermore, the influence of embedding length on deformation has been studied to determine the reasonable embedded length, which helps reduce deformation and ensure landslide stability. The results reveal that (1) at a constant embedded length, horizontal displacement increases with the thickness of the first soft bedrock, meanwhile the maximum shear force remains constant, and the bending moment first increases followed by subsequent decrease; (2) with an increase in the embedded length, horizontal displacement and the maximum shear force of the pile in the embedded bedrock decrease, whereas the bending moment increases; (3) the maximum internal forces and horizontal displacement increase with a decrease in the subgrade reaction modulus of the first weak rock; and (4) the reasonable embedded length of an anti-slide pile increases with a decrease in the subgrade reaction modulus of the first weak bedrock. The proposed approach can be employed to design anti-slide piles in similar landslide regions to control pile-head deformation.
6
Wei, Wei, Zhi Dong Yang, Jun Wei Han und Ting Gao. „Internal Force Decoupling Control of Hyper-Redundant Shaking Table Based on Stiffness Matrix“. Applied Mechanics and Materials 681 (Oktober 2014): 115–20. http://dx.doi.org/10.4028/www.scientific.net/amm.681.115.
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A novel internal force decoupling control strategy of hyper-redundant shaking table based on stiffness matrix is proposed in this paper. The linear models of electro-hydraulic servo system and mechanical system are built by considering the shaking table moving in a small range around the zero point. Internal forces are given through a transformation of cylinder forces which can be acquired from the pressure sensors. By meshing top platform of the shaking table in different directions, the stiffness matrix between the redundancy displacements and internal forces are given through dynamics equations including inertia and shear parts. The IFDC controller is designed to feedback the redundancy displacement caused by internal forces to the input current of the servovalve. Simulation results show that the proposed method is capable to reduce internal forces effectively.
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Tan, Xiao Jing, und Bin Wu. „Mixed Force and Displacement Control Strategy in Pseudo-Dynamic Tests for Structures with Large Stiffness“. Advanced Materials Research 639-640 (Januar 2013): 1133–36. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.1133.
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Pseudo-dynamic testing using force- mixed control strategy is presented for structures with large stiffness. In this proposed method, the displacement response of the specimen measured by a linear variable displacement transducer with higher resolution than that in the actuator is fed back. A proportional-integral controller is adopted in the outer displacement control loop, and a coefficient CF is employed to convert the displacement to force command. Numerical and experimental validations show that this method exhibits excellent performance in terms of stability and accuracy if proper controller parameters are adopted and is superior to the conventional displacement control method for large-stiffness structures.
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He, Xiaodong, Xiuchang Huang und Hongxing Hua. „Performance of a friction ring DVA for vibration control of a flywheel“. INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, Nr. 4 (01.08.2021): 2449–57. http://dx.doi.org/10.3397/in-2021-2140.
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A flexible ring DVA with friction contact interfaces (essentially a viscoelastic-friction DVA) is proposed to suppress vibration of a flywheel, two other cases are also studied, i.e., viscoelastic DVA and friction DVA. Based on an equivalent 3 degrees of freedom (DOFs) dynamic model, displacement response of the flywheel-DVA are obtained by using harmonic balance method (HBM). It is shown that all three types of DVA can suppress vibration of the flywheel effectively, bandwidth of the viscoelastic-friction DVA is enlarged due to the existence of friction interface. Performances of the DVA are evaluated by analyzing the displacement responses and forces (i.e., spring force, damping force and friction force). It is shown that the frequency corresponding to the turning point on the response curve is the critical frequency at which dynamic vibration absorption takes place, and it is also the frequency at which the friction force begins to take effect. In the process of emergence and disappearance of the dynamic vibration absorption, the friction force plays a role similar to a "switch"
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Karimpour, Babak, Ali Keyhani und Javad Alamatian. „New Active Control Method Based on Using Multiactuators and Sensors Considering Uncertainty of Parameters“. Advances in Civil Engineering 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/180673.
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New approach is presented for controlling the structural vibrations. The proposed active control method is based on structural dynamics theories in which multiactuators and sensors are utilized. Each actuator force is modeled as an equivalent viscous damper so that several lower vibration modes are damped critically. This subject is achieved by simple mathematical formulation. The proposed method does not depend on the type of dynamic load and it could be applied to control structures with multidegrees of freedom. For numerical verification of proposed method, several criterions such as maximum displacement, maximum kinetic energy, maximum drift, and time history of controlled force and displacement are evaluated in two- , five- , and seven-story shear buildings, subjected to the harmonic load, impact force, and the Elcentro base excitation. This study shows that the proposed method has suitable efficiency for reducing structural vibrations. Moreover, the uncertainty effect of different parameters is investigated here.
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Liu, Cheng Qing, Jun Jun Li, Chi Chen, Zhi Bin Tu, Xiao Dan Sun und Bin He. „Analysis and Research on Reinforcement and Reconstruction Method of Adding Shear Wall for Multi-Story Frame Structure“. Applied Mechanics and Materials 351-352 (August 2013): 442–45. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.442.
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Recently, earthquakes occurred frequently, and our country has established a new seismic code. As the seismic intensity increases, some low frame structures cannot reach the requirements of layer displacement, layer displacement angle, stability, etc. Thus, they require reinforcement. The shear wall is good for resisting lateral force, and rational shear wall can control the shifting and shaking efficiently, thus making the distribution of internal force more reasonable. Through analysis on reinforcement and reconstruction method of adding shear walls for multi-story frame structure, the rules in terms of different layer displacement, layer displacement angle and overturning moment are found out, and the added shear wall, which can efficiently improve seismic fortification intensity, can serve as the main component for resisting lateral force. The conclusions are as follows: under earthquake action, through the method of adding shear wall, the deformation, layer displacement and layer displacement angle can be controlled effectively. Besides, the integrity and seismic behavior are inhanced, achieving the goal of improving anti-seismic grade of structure.
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Zhao, Jinsong, Gang Shen, Weidong Zhu, Chifu Yang und Sunil K. Agrawal. „Force tracking control of an electro-hydraulic control loading system on a flight simulator using inverse model control and a damping compensator“. Transactions of the Institute of Measurement and Control 40, Nr. 1 (10.06.2016): 135–47. http://dx.doi.org/10.1177/0142331216651326.
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The electro-hydraulic control loading system (EHCLS) of a flight simulator is mainly used to simulate the force feel of flying a real airplane. A double-loop model, including control and hydraulic mechanism of the EHCLS, is established and its force–displacement impedance is analysed to evaluate force tracking performances and its stability. An approximated feed-forward inverse model controller is designed using a zero phase error compensation method for expanding the frequency bandwidth of the inner loop because the identified force closed-loop model is a nonminimum phase system and its direct inverse model is unstable. Modelling error between the designed feed-forward inverse model and the actual plant is discussed and a damping compensator is presented to increase stability of the EHCLS. Theoretical analysis, simulation and experimental results show that the control methods presented are feasible and can effectively improve force feel fidelity and stability of the EHCLS.
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Wang, Wei Wei, Ze Chen, Jing Bo Yu und Man Zhou. „Numerical Simulation on the Multi-Point Forming of Sail Surfaces under Force-Displacement Separated Control“. Applied Mechanics and Materials 217-219 (November 2012): 1959–63. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.1959.
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The forming and springback of sail surface during the multi-point forming under force-displacement separated control (MPF-FD) was studied. Numerical simulation method was adopted to study the springback of sail surfaces with different radius, sheet thicknesses and forming forces. The results show that the springbacks on two directions influence each other. The springback on the bigger radius direction is on the leading role, and will influence that on the smaller direction. On the direction of the bigger radius, the springback is decreased with the increase of sheet thickness, forming force and decrease of the radius. On the direction of the smaller radius, the springback is decreased with the decrease of the sheet thickness and the increase of the forming force, and the radius has a small impact on springback.
13
Mao, Dawei, und Yu Chen. „Analysis of the bolt performance with shear force“. E3S Web of Conferences 198 (2020): 01013. http://dx.doi.org/10.1051/e3sconf/202019801013.
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The bolt anchorage performance with shear force has been analysed by analytical method in this paper. By coding in Matlab, the loop and the judgment statement can be used to control the displacement angle. The force-displacement curve of the analysis model from the beginning of loading to the failure of the bolt under a certain displacement loading angle is obtained. In the test and field, the values of displacement and force before failure and the load-displacement curves before the peak value can be obtained by using the program with the parameters. The bolt deformation in different strength surrounding rock mass and the anchoring influence of the rock bolt with different diameters have been studied. The resultant displacement increases linearly with the increase of the bolt, and the resultant force increases exponentially with the increase of the bolt.
14
Zhao, Yong, Hong Bao, Xuechao Duan und Hongmei Fang. „The Application Research of Inverse Finite Element Method for Frame Deformation Estimation“. International Journal of Aerospace Engineering 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/1326309.
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A frame deformation estimation algorithm is investigated for the purpose of real-time control and health monitoring of flexible lightweight aerospace structures. The inverse finite element method (iFEM) for beam deformation estimation was recently proposed by Gherlone and his collaborators. The methodology uses a least squares principle involving section strains of Timoshenko theory for stretching, torsion, bending, and transverse shearing. The proposed methodology is based on stain-displacement relations only, without invoking force equilibrium. Thus, the displacement fields can be reconstructed without the knowledge of structural mode shapes, material properties, and applied loading. In this paper, the number of the locations where the section strains are evaluated in the iFEM is discussed firstly, and the algorithm is subsequently investigated through a simple supplied beam and an experimental aluminum wing-like frame model in the loading case of end-node force. The estimation results from the iFEM are compared with reference displacements from optical measurement and computational analysis, and the accuracy of the algorithm estimation is quantified by the root-mean-square error and percentage difference error.
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Jasiński, Radosław, Krzysztof Stebel und Jarosław Domin. „Application of the DIC Technique to Remote Control of the Hydraulic Load System“. Remote Sensing 12, Nr. 21 (09.11.2020): 3667. http://dx.doi.org/10.3390/rs12213667.
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Displacements or deformations of materials or structures are measured with linear variable differential transducers (LVDT), fibre optic sensors, laser sensors, and confocal sensor systems, while strains are measured with electro-resistant tensometers or wire strain gauges. Measurements significantly limited to a point or a small area are the obvious disadvantage of these measurements. Such disadvantages are eliminated by performing measurements with optical techniques, such as digital image correlation (DIC) or electronic speckle pattern interferometry (ESPI). Many devices applied to optical measurements only record test results and do not cooperate with the system that exerts and controls load. This paper describes the procedure for preparing a test stand involving the Digital Image Correlation system ARAMIS 6M for remote-controlled loading. The existing hydraulic power pack (ZWICK-ROELL) was adapted by installing the modern NI cRIO-9022 controller operating under its own software developed within the LABVIEW system. The application of the DIC techniques to directly control load on the real structure is the unquestionable innovation of the described solution. This led to the elimination of errors caused by the test stand susceptibility and more precise relations between load and displacements/strains which have not been possible using the previous solutions. This project is a synergistic and successful combination of civil engineering, computer science, automatic control engineering and electrical engineering that provides a new solution class. The prepared stand was tested using two two-span, statically non-determinable reinforced concrete beams loaded under different conditions (force or displacement). The method of load application was demonstrated to affect the redistribution of bending moments. The conducted tests confirmed the suitability of the applied technique for the remote controlling and recording of test results. Regardless of the load control method (with force or displacement), convergent results were obtained for the redistribution of bending moments. Force-controlled rotation of the beam section over the support was over 50% greater than rotation of the second beam controlled with an increase in the displacement.
16
Sareban, M. „Evaluation of Three Common Algorithms for Structure Active Control“. Engineering, Technology & Applied Science Research 7, Nr. 3 (12.06.2017): 1638–46. http://dx.doi.org/10.48084/etasr.1150.
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Recently active structure controllers were considered to deal with the impact of earthquake forces and the result of the investigations provided multiple algorithms to calculate force control and many different ways to apply these forces on the structure. In this study, the efficiency and effectiveness of three methods (linear quadratic regulator, fuzzy logic and pole assigning) are investigated. In addition, three buildings with different height classes with an active tuned mass damper (ATMD) on the top floor are considered to compare the active control methods. Examples with known mass and stiffness and with variable mass are considered. The results show that all three control methods used for the ATMD device reduce the structural response. The fuzzy control method, caused a sharp decline in relative displacement of building floors up to 80%. But in LQR and pole allocation procedures the applied force is limited. The best performance of fuzzy control is for high-rise buildings. The three different methods of control are stable in different masses and even under a random change of floor masses, their effectiveness can be trusted.
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Malesińska, Agnieszka, Mariusz Rogulski, Pierfabrizio Puntorieri, Giuseppe Barbaro und Beata Kowalska. „Displacements of the pipe system caused by a transient phenomenon using the dynamic forces measured in the laboratory“. Measurement and Control 51, Nr. 9-10 (14.09.2018): 443–52. http://dx.doi.org/10.1177/0020294018799370.
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Background: When transporting liquids, in particularly over long distances, dynamic forces in the system can present a risk. The larger the system size, and the greater the pressure, the more harmful the impact is of such forces. Water is transported in this way for domestic, industrial, and fire-fighting purposes. One of the impulses of dynamic force application may be the transition of the pressure wave in the water hammer. Methods: In this paper, the results of measured dynamic forces and associated displacements recorded on the model caused by transient flow conditions are presented. For measured forces, the displacements of the pipe were also calculated by using the oscillation motion equations. Force measurements and displacement analyses were carried out in laboratory on the model of a simple fire protection system equipped with three nozzles. Results and Conclusions: The measurement results and calculations were used to calibrate a mathematical model created using MATLAB software.
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Asadian-Ardakani, Mohammad Hossein, Mohammad Reza Morovvati, Mohammad Javad Mirnia und Bijan Mollaei Dariani. „Theoretical and experimental investigation of deep drawing of tailor-welded IF steel blanks with non-uniform blank holder forces“. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 231, Nr. 2 (06.08.2016): 286–300. http://dx.doi.org/10.1177/0954405415577559.
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Tailor-welded blank is one of the promising technologies in the application of lightweight materials for auto body parts manufacturing. The material discontinuity across the weld line results in an inhomogeneous deformation and weld line displacement. In this study, a two-dimensional analytical model is proposed to predict the tension distribution along the cross section. An energy method is used to calculate the restraining force due to bending, sliding, and unbending phenomena on the die and punch radii. To control the weld line movement, a blank holder force control strategy is proposed to achieve force equilibrium at the bottom of the part across the weld line. Finite element simulations are performed to study the effect of die and punch radii, friction coefficient, thickness ratio, and blank holder forces on the weld line displacement in strip drawing process. Under a uniform blank holder force, the weld line moves toward the thicker/stronger side implying a higher blank holder force is required for the thinner/weaker side. The results show that the weld line displacement can be controlled by an appropriate blank holder force adjustment. In order to control the weld line movement in square cup deep drawing, blank holder force on the thinner side is increased and its influences on the deformation process are investigated. Comparisons of material draw-in, weld line movement, and forming force show a good agreement between the theoretical, numerical, and experimental results.
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Li, Gang, Hong-Nan Li und Qi-Feng Liu. „Application of Fuzzy Control with Market-Based Control Strategy to Structures“. Mathematical Problems in Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/132010.
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The market-based control as a control strategy is developed based on an analogy between the control force-energy source in the structural area and the supply demand in the free market. The optimal problem of control force from an actuator is transformed to that of the allocation resource in the market. Since the supply-demand relation model and iteration procedure for the optimal price solution are necessary and relatively hard to understand and perform for civil engineers, the fuzzy logical method is proposed in the framework of the market-based control to acquire an equivalent system corresponding to the market-based control method. An equivalent fuzzy logical rule is established through analyzing a single-degree-of-freedom system with the controller using the MBC strategy under earthquakes. The results show that the fuzzy logical method is able to also reduce the displacement and acceleration responses effectively similar to the MBC method, and the consumed computational time for the fuzzy logical method is obviously saved.
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Gluck, J., Y. Ribakov und A. N. Dancygier. „Selective Control of Base-Isolated Structures with CS Dampers“. Earthquake Spectra 16, Nr. 3 (August 2000): 593–606. http://dx.doi.org/10.1193/1.1586129.
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Addition of dampers to a base isolator reduces base displacements but may increase floor accelerations and interstory drifts. This paper presents a “selective control approach” for the design of base-isolated active controlled structures with Controlled Stiffness Dampers (CSD). According to this approach the dampers are activated only within a given range of the base displacement. The optimal damping forces are calculated according to structure's displacements and velocities. However, because of the CS dampers' structure the actual application of the forces is independent of the displacement and the velocity that are transferred to the device. These forces depend only on the geometry and on the mechanical properties of the devices' springs. The efficiency of the proposed method is demonstrated in a numerical example.
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Yang, Meng Gang, und Zhu Qing Yang. „Longitudinal Vibration Control of Floating System Bridge Subject to Vehicle Braking Force with Viscous Dampers“. Advanced Materials Research 446-449 (Januar 2012): 1256–60. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.1256.
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Excessive longitudinal displacement of the girder would emerge in floating system bridge subject to vehicle braking force because of non-restraint in longitudinal direction of the bridge. To reduce it, viscous dampers are set up in longitudinal direction between the girder and the tower of floating system bridge, and the influence matrix method is applied to determine the optimal parameters of viscous dampers. The analysis results of Pingsheng Bridge show that the longitudinal displacement of the girder is relatively large for floating system bridge, and it can be effectively controlled by viscous dampers with optimal parameters obtained by influence matrix method.
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Tian, Lianfang. „An Intelligent Control Method Based on Fuzzy Logic for a Robotic Testing System for the Human Spine“. Journal of Biomechanical Engineering 127, Nr. 5 (31.05.2005): 807–12. http://dx.doi.org/10.1115/1.1992520.
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In previous biomechanical studies of the human spine, we implemented a hybrid controller to investigate load-displacement characteristics. We found that measurement errors in both position and force caused the controller to be less accurate than predicted. As an alternative to hybrid control, a fuzzy logic controller (FLC) has been developed and implemented in a robotic testing system for the human spine. An FLC is a real-time expert system that can emulate part of a human operator’s knowledge by using a set of action rules. The FLC provides simple but robust solutions that cover a wide range of system parameters and can cope with significant disturbances. It can be viewed as a heuristic and modular way of defining a nonlinear, table-based control system. In this study, an FLC is developed which uses the force difference and the change in force difference as the input parameters, and the displacement as the output parameter. A rule-table based on these parameters is designed for the controller. Experiments on a physical model composed of springs demonstrate the improved performance of the proposed method.
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Puspita, Annisaa Dina, und Anis Rosyidah. „Force Based Design and Direct Displacement Based Design for Dual System Structure“. Logic : Jurnal Rancang Bangun dan Teknologi 19, Nr. 3 (30.11.2019): 162. http://dx.doi.org/10.31940/logic.v19i3.1454.
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The Force Based Design (FBD) and the Direct Displacement-Based Design (DDBD) are methods for designing seismic-resistant buildings. Building structures designed, are expected to be suitable with the purpose and usefulness of a building. For this reason, this study compares the performance of dual system structures using the DDBD and FBD methods that aim to prove better performance with consideration of safety against users during an earthquake. This research method uses design analysis method to compare the value of the base shear force, reinforcement ratio, and performance level using software for static nonlinear pushover analysis. The results showed the value of the base shear force x direction of the DDBD method was 17.57% smaller than the FBD method, whereas for the y direction the DDBD value was greater than 9.38% of the FBD. The value of the reinforcement ratio of the beam, column and shear wall results is greater DDBD than FBD. The actual drift of the DDBD and FBD methods is slightly different. So that both are at the same level of performance, namely damage control. The performance level has not reached the performance target of life safety design in DDBD, but the structure has met the level performance requirements for offices.
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Hua, Yizhou, und Huangqiu Zhu. „Sensorless Control of Bearingless Permanent Magnet Synchronous Motor Based on LS-SVM Inverse System“. Electronics 10, Nr. 3 (23.01.2021): 265. http://dx.doi.org/10.3390/electronics10030265.
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In order to solve the problems of low integration, low reliability, and high cost caused by mechanical sensors used in bearingless permanent magnet synchronous motor (BPMSM) control systems, a novel speed and displacement sensorless control method using a least-squares support vector machine (LS-SVM) left inverse system is proposed in this paper. Firstly, the suspension force generation principle of the BPMSM is introduced, and the mathematical model of the BPMSM is derived. Secondly, the observation principle of the left inverse system is explained, and the left reversibility of the established speed and displacement subsystem is proved. Thirdly, the left inverse systems of the speed and displacement subsystems are constructed by using the LS-SVM, and the complete speed and displacement sensorless control system is constructed. Finally, the simulations and experiments of the proposed method are performed. The research results demonstrate that the proposed observation method can identify the speed and displacement quickly and accurately, and the sensorless control method can realize the stable operation of the BPMSM without speed and displacement sensors.
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Kim und Sung. „Design of a Tribotester Based on Non-Contact Displacement Measurements“. Micromachines 10, Nr. 11 (31.10.2019): 748. http://dx.doi.org/10.3390/mi10110748.
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A tribotester with an integrated load sensor based on a strain gauge is typically used to measure the friction coefficient generated by the contact-related sliding motion of two objects. Since the friction coefficient is obtained by dividing the measured friction force by the applied normal force, the normal and friction forces must be measured for accurate analysis. In this study, a tribotester was used to measure the displacement of a cantilever tip using the fiberoptic sensor in a non-contact method. The friction coefficient measurement using the fiberoptic sensor was proven to be valid by calibrating the tip displacement due to normal/friction forces after designing a basic structural cantilever tip based on experiments and simulation analyses. The results obtained by using the fiberoptic sensor-cantilever tip-based tribotester were compared with those obtained using commercial and/or custom-built tribotesters under the same conditions. By designing various shapes of cantilever tips and using simulation analysis, the calibrations of the normal/friction forces and tip displacement could be verified and the coupling effect was evaluated. The performance and reliability of the fiberoptic sensor-cantilever tip-based tribotester, which can be used to determine the normal/friction forces by non-contact displacement measurements without a strain gauge, were verified.
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Hazaveh, Nikoo K., J. Geoffrey Chase, Geoffrey W. Rodgers und Stefano Pampanin. „Smart semi-active MR damper to control the structural response“. Bulletin of the New Zealand Society for Earthquake Engineering 48, Nr. 4 (31.12.2015): 235–44. http://dx.doi.org/10.5459/bnzsee.48.4.235-244.
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One advanced means of protecting structures against earthquake ground motions is the use of semi-active devices to customise and limit structural response. Thus, the design, modelling and analysis of different semi-active control devices have received increasing research attention. This study presents a method to determine optimal control forces for magneto-rheological (MR) dampers, using three algorithms: a discrete wavelet transform (DWT), a linear quadratic regulator (LQR), and a clipped-optimal control algorithm. DWT is used to obtain the local energy distribution of the motivation over the frequency bands to modify conventional LQR. The clipped-optimal control algorithm is used to get the MR damper control force to approach the desired optimal force obtained from modified LQR. A Bouc-Wen phenomenological model is utilized to capture the observed nonlinear behaviour of MR dampers. Time history analysis for a single degree of freedom (SDOF) with periods of T= 0.2-5.0 sec is utilized to compare the impact of using classic and modified LQR in controlling the MR damper force under 20 design level earthquakes of the SAC (SEAOC-ATC-CUREE) project. Performance is assessed by comparing the maximum displacement (Sd), total base shear (Fb) and the controller energy. This study shows the proposed modified LQR is more effective at reducing displacement response than conventional LQR. The modified LQR method reduces the median value of uncontrolled Sd by approximately 40% to 88%, over all periods to 5.0 seconds. Moreover, the modified LQR uses about 45% less energy than conventional LQR. Overall, these results indicate the robustness of the proposed method to mitigate structural response and damage using MR devices.
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Sun, Chuanyu, Hang Yang, Shangke Han, Hongchang Ding, Jiaqing Li und Ning Han. „Control System Design for 16/6/8 Double-Stator Bearingless Switched Reluctance Motor“. Mathematical Problems in Engineering 2021 (30.08.2021): 1–15. http://dx.doi.org/10.1155/2021/4727917.
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The 16/6/8 double-stator bearingless switched reluctance motor (DSBSRM) is used as the object of study in this paper. To solve the problem of torque and levitation force ripples in this motor, a control system direct force control (DFC) and direct instantaneous torque control (DITC) based on the torque sharing function (TSF) are proposed. With the strong nonlinearity and approximation capability of radial basis function neural networks, the torque and levitation force observer are designed. The observed torque and levitation forces are used as feedback for the internal loop control, which is combined with the external loop control to make a double closed-loop control. In order to further improve the output torque and system robustness and suppress the torque ripple in steady-state process, the motor winding method is optimized and a set of switching angles is added on the basis of TSF. The simulation results verify the effectiveness and superiority of the proposed control method. It effectively suppresses speed ripple and reduces torque and levitation force fluctuations and rotor radial displacement jitter.
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Mohammed Saeed, Najmadeen, Shna Jabar Abdulkarim und Hawkar Ali Haji. „Direct Displacement Control of Deformed Double Layer Dome“. ISSUE SIX 4, Nr. 6 (30.06.2020): 1–14. http://dx.doi.org/10.25079/ukhjse.v4n1y2020.pp1-14.
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Space structures such as double layer dome is light and active structural system that used for various structural application, for instance structural covers large areas such as exhibition halls, stadium and concert halls. They are aesthetically pleasing in appearance as well as the architectural requirement, in which tolerances of structural shape under changing service conditions are very significant, which high appearance accuracy is requested in some applications. Due to many reasons such as loading, these type of structures may suffer from a noticeable deflection, which leads to a significant potential undesired appearance of the shape. In this situation, the displacements may need to be reduced or eliminated. In this study, by applying the shape adjustment technique that its scheme is depend on the linear force method, shape restoration is performed to the double layer dome model in three different cases corresponding to the directions of loadings were considered. The improvement of controlling nodal displacement can be achieved through using a rather simple and direct method, due to calculating necessary length of actuators by applying a single formulation. It is found that if the number of provided actuators are satisfactory, controlling of all the displaced joints could be performed by a very small percentage of discrepancy, even if the controlled joints connection is not direct with the adjustable members. The technique of shape adjustment is very efficient for double layer dome model, and it can roughly eliminate the displacement of definite joints (Exterior joints only) by simply changing the length of certain bars by eo amount
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Shih, Ming-Hsiang, und Wen-Pei Sung. „Experimental Verification of Applying Active Control Method as Virtual Support for Relief Bridge“. Advances in Civil Engineering 2019 (19.06.2019): 1–12. http://dx.doi.org/10.1155/2019/8505091.
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When natural disasters cause bridges to collapse, the delivery of rescue equipment and supplies to remote disaster areas is impeded and disaster relief efforts are thus delayed. In this study, to enhance and improve light bridges for disaster relief, a neutral equilibrium mechanism (NEM) is proposed to adjust the internal force of the bridge and reduce the deformation of the bridge. The NEM is installed at the center of a bridge to form a virtual bridge pier. A prototype of the NEM, composed of a pair of prestressed steel tendons, two pairs of anchor seats, a rotation cantilever arm mechanism, and a pair of radio-controlled (RC) servos, is proposed to test and verify the control effect of a bridge with the NEM. Test and analysis results show the following: (1) The rotation angle of the cantilever arm can be rotated by the RC servo to appropriate angles to provide adequate upwards resultant force to balance the moving load. (2) The vertical displacement of the bridge can be controlled to close to zero by this proposed NEM. (3) The maximum vertical displacement at the midpoint of a bridge with the NEM control mechanism can be controlled to far below 1/400 of the span of the bridge required by the design criteria. (4) A bridge under the control of an NEM under a low-speed moving load with various control gains achieves fine displacement reduction effects, but the displacement reduction effect for a high-speed moving load with low control gain decreases. Test results also show that the bearing capacity of an existing bridge with an NEM can be increased and the weight of the bridge can be reduced. The effective span of a bridge can be increased without increasing the depth of the cross section. The feasibility and practicality of applying this proposed NEM to form a virtual pier of a bridge have been verified in this study.
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Ta, Thi-Na, Cao-Sang Tran und Yunn-Lin Hwang. „The Kinematic and Dynamic Analysis of Hydraulic Control System Based on the Lagrangian Force Method“. International Journal of Computational Methods 15, Nr. 05 (05.06.2018): 1850041. http://dx.doi.org/10.1142/s021987621850041x.
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In this paper, the hydraulic control system design and dynamic analysis are considered in superior calculation efficiency based on Lagrangian method and fundamental laws for getting control algorithms to investigate about hydraulic system how to control hydraulic system and take hydraulic controller to the optimization. The systems built in dynamical parameters are associated hydraulic control system achieved with control parameters. And then, an interface is achieved. The relations between control parameters are obtained. The numerical tools are going to determine all kinematic parameters of bodies such as displacement, velocities, accelerations as well as reaction forces are responded. The AMESim and RecurDyn are used such Computer Aided Engineering (CAE) techniques to solve the numerical examples in this paper. Those examples will imply that the equation of motion based on Euler–Lagrange equation and characteristic effect of force is executable. Through results, we could achieve control improvement at different hydraulic systems.
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Zhang, Jin, Xin Chang Luo, Jian Guo Cai, Jian Feng und Xiao Jing Yang. „Influence of Segmented Construction Methods on the Prestressed State of Truss String Structure Roof of Xinjiang Exhibition Center“. Advanced Materials Research 163-167 (Dezember 2010): 85–89. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.85.
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Taking Xinjiang Exhibition Center Roof as an example, three models ("No construction stage" model, "Stretching on the ground" model and "Flow construction stage" model) were set up and analyzed with consideration of different segmented construction methods. The results show that the effect of the segmented construction method on the prestressed state of long-span truss string structures is significant. For the "No construction stage" model, the maximal cable force during construction is the largest among three models, while there are great differences between each cable force. However, the maximal displacement of sliding ends is the smallest among three models. For the "Stretching on the ground" model, the tension control force is the most uniform. This is because the cable of every truss is pre-tensioned independently, which causes no influence on other cables. For the "Flow construction stage" model, the maximal displacement of sliding ends and the uniformity of cable forces of the truss string structures are between those given by the other two models.
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Imiełowski, Szymon, Aniela Glinicka und Cezary Ajdukiewicz. „Experimental buckling path of compressed bars under displacement control“. Budownictwo i Architektura 13, Nr. 2 (11.06.2014): 209–14. http://dx.doi.org/10.35784/bud-arch.1897.
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Buckling and postcritical analysis of prismatic metal bars, including complex cycles of loading are considered in the paper. The postbuckling path analysis of bars loaded in the form of increasing displacements is discussed in detail. The results of experimental research are reported as a dependence of the force P versus lateral deflection f as well as total shortening of the rod u. It is stated that only the simultaneous analysis of both methods of presentation of results comprises a complete tool for developing the column response. Particularly, the response that appears in the first, linear elastic phase of loading can be observed on P-u diagrams. The increase of the compressing force causes visible shortening of the bar without its buckling. This important phenomenon is not usually included in stability considerations of prismatic rods.
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Zhang, Xi, Ya Bin Cui, Peng Xia, Xin Xing Liu und Miao Yu. „The Design of Force-Displacement Characteristics Test System for Electromagnet“. Applied Mechanics and Materials 457-458 (Oktober 2013): 1546–49. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.1546.
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Electromagnet for valve is a key executive device of electromagnetic valve control system, as a dynamic element, force and displacement characteristics of electromagnet, directly affect the reliable performance of devices made of it. By reference to other electromagnet testing standard and method, proposed a based on vc6.0 and stepper motor of force and displacement characteristics for electromagnet test system. The system consists mechanical platform, pressure sensor, data acquisition card and PC test software. The system is easy to operate, high degree of automation, stable performance. Provides an auxiliary electromagnet selection testing and inspection tools, can improve the work efficiency.
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Lee, Seong Beom, Heung Seob Kim, Shin Hur, Wan Doo Kim, Chang Su Woo und Chan Seok Park. „A Viscoelastic Model for an Automotive Transmission Rubber Mount“. Key Engineering Materials 306-308 (März 2006): 995–1000. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.995.
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An automotive transmission (TM) rubber mount is a device that is used in automotive systems to cushion the loads transmitted from the vehicle body structure. A TM rubber mount is used to support the engine in the vertical direction. However, the dynamic behavior of loaded rubber mount is not yet known to a reasonable degree of accuracy. The relationship between the force applied to a TM rubber mount and the resulting deformation exhibits features of viscoelasticity. Therefore, in this study, viscoelastic properties were measured during ramp-toconstant displacement control tests. A force-displacement relationship for a TM rubber mount is important for multi-body dynamic numerical simulations. Hence, an explicit force-displacement relationship was developed and expressed in terms of a force relaxation function. A method that can be used to determine the force-displacement relationship from experimental data for a TM rubber mount was also developed. Solutions were obtained and the results were compared with experimentally measured force-displacement behavior. The predictions of the proposed forcedisplacement relationship were in very good agreement with the experimental results.
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Xu, Jin, Yonggang Sun, Zhifu Li, Xiantao Zhang und Da Lu. „Analysis of the Hydroelastic Performance of Very Large Floating Structures Based on Multimodules Beam Theory“. Mathematical Problems in Engineering 2017 (2017): 1–14. http://dx.doi.org/10.1155/2017/6482527.
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The hydroelastic behavior of very large floating structures (VLFSs) is investigated based on the proposed multimodules beam theory (MBT). To carry out the analysis, the VLFS is first divided into multiple submodules that are connected through their gravity center by a spatial beam with specific stiffness. The external force exerted on the submodules includes the wave hydrodynamic force as well as the beam bending force due to the relative displacements of different submodules. The wave hydrodynamic force is computed based on three-dimensional potential theory. The beam bending force is expressed in the form of a stiffness matrix. The motion response defined at the gravity center of the submodules is solved by the multibody hydrodynamic control equations; then both the displacement and the structure bending moment of the VLFS are determined from the stiffness matrix equations. To account for the moving point mass effects, the proposed method is extended to the time domain based on impulse response function (IRF) theory. The method is verified by comparison with existing results. Detailed results through the displacement and bending moment of the VLFS are provided to show the influence of the number of the submodules and the influence of the moving point mass.
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Wong, R., und D. B. Cherchas. „Hybrid Constraint Space Dynamics and Control for Robot Manipulators“. Journal of Vibration and Control 10, Nr. 11 (November 2004): 1563–84. http://dx.doi.org/10.1177/1077546304042025.
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In this paper we present the development of a hybrid constraint space dynamics modeling technique and position/force controller for robotic manipulator control in constrained environments. The method utilizes a constraint space dynamic model in which the model coordinates are displacement along the constraint trajectory and the normal force between the manipulator end-effector and the environment. The dynamic model is constructed by transforming the conventional joint space manipulator dynamics equations into their constraint space equivalents through the application of mapping functions, which relate differential displacements and velocities in the constraint space coordinate system to the joint space coordinate system. Control algorithms may then be applied to the simplified dynamic structure of the constraint space equations of motion in order to produce a vector of manipulator joint torques which will satisfy both position and force requirements along the environmental constraint. Actuator constraints and momentum compensating techniques are also used to ensure that the position and force control problems are completely decoupled from one another. A computer torque control algorithm is then applied to a two-degrees-of-freedom prismatic robot and simulations are carried out with two different constraint surfaces, i.e. a planar, and a concave circular environment. The results of these simulations show that the controller, implemented in hybrid constraint space provides good position and force control.
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Zhang, Menghua, Xin Ma, Xuewen Rong, Rui Song, Xincheng Tian und Yibin Li. „A novel energy-coupling-based control method for double-pendulum overhead cranes with initial control force constraint“. Advances in Mechanical Engineering 10, Nr. 1 (Januar 2018): 168781401775221. http://dx.doi.org/10.1177/1687814017752213.
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A novel energy-coupling-based control method for under-actuated double-pendulum overhead cranes with initial control force constraint is proposed in this article. The significant feature of the designed controller is its superior control performance as well as its strong robustness with respect to parameter variations and external disturbances. By incorporating a smooth hyperbolic tangent function into the control law, the proposed controller guarantees soft start of the trolley. Moreover, to improve the transient performance of the crane system, coupling behavior among the trolley movement, the hook swing, and the payload swing is enhanced by introducing a generalized payload horizontal-displacement signal. Lyapunov techniques and LaSalle’s invariance theorem are utilized to prove the stability of the designed closed-loop system. Simulation results demonstrate that the new energy-coupling control method achieves superior control performance and strong robustness over different payload masses, cable lengths, desired positions, and external disturbances with reduced initial control force.
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Yang, Zhi Jun, You Dun Bai, Su Juan Wang, Xin Du Chen, Qiang Liu, Ke Tian Li, Han Wang und Xin Chen. „The Development of an Displacement Sensor Embedded Voice Coil Motor Based Fast-Tool-Servo for the Machining of Micro-Structure“. Key Engineering Materials 625 (August 2014): 258–61. http://dx.doi.org/10.4028/www.scientific.net/kem.625.258.
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The Fast Tool Servo (FTS) is widely used for the machining of micro-structures, especially for optical micro lens array. The working principle of FTS is that a voice coil motor or a piezoelectric (PZT) actuator is used as the driving elements, and the flexure hinges are developed as the guide mechanisms. In addition, an optical encoder is applied to measure the displacement. However, the existing design of FTS is too complicated and expensive. One reason is that the stroke of the FTS for the fabrication of optical micro lens array is only a few hundred micrometers, while its precision reaches to nanometric range, thus the optical encoder in not applicable. On the other hand, there exists sluggish and creep for piezoelectric materials, which makes the control of displacement difficult. This paper develops a displacement sensor embedded voice coil motor. In the design, the driving element is ampere force of the voice coil motor which is a linear ratio to the input current. Both the two covers are thin plates which serve as compliant mechanism by supporting the deformation at the Radial direction and provide linear stiffness in the axial direction. Therefore, the output displacement is proportional to the ampere force. The existence of external force affects the actual displacement, an embedded capacitor serves as displacement sensor will detects the real displacement, and the external force can be estimated by the current and measured displacement, which makes the motion control easy. At the same time, a multiphysics model of the developed FTS is built in this study by using finite element method and the displacement control under different cutting force is studied. The experimental results show that the developed FTS is efficient for achieving short stroke with high precision.
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Chapman, Edward M., und Matthew Bryant. „Bioinspired passive variable recruitment of fluidic artificial muscles“. Journal of Intelligent Material Systems and Structures 29, Nr. 15 (09.07.2018): 3067–81. http://dx.doi.org/10.1177/1045389x18783070.
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This article presents a novel, passive approach to creating variable actuator recruitment in bundles of fluidic artificial muscles. The passive recruitment control approach is inspired by the functionality of mammalian muscle tissues, in which a single activation signal from the nervous system sequentially triggers contraction of progressively larger actuation elements until the required force is generated. Biologically, this behavior is encoded by differences in electrical resistance properties between smaller and larger muscle-fiber groups. The approach presented here produces analogous behavior using a uniform applied pressure to all fluidic artificial muscles while creating differential pressure responses and threshold pressures among the fluidic artificial muscles via tailored bladder elasticity parameters. A model for using elastic bladder stiffness to control an artificial muscle bundle with a single valve is explored and used to compare a bundle of fluidic artificial muscles with both low and high threshold pressure units to a single fluidic artificial muscle of equivalent displacement and force capability. The results of this analysis indicate the efficacy of using this control method; it is advantageous in cases where a wide range of displacements and forces are necessary and can increase efficiency when the system primarily operates in a low-force regime but requires occasional bursts of high-force capability.
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Zheng, Hongyu, Shenao Ma und Yahui Liu. „Vehicle braking force distribution with electronic pneumatic braking and hierarchical structure for commercial vehicle“. Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 232, Nr. 4 (28.02.2018): 481–93. http://dx.doi.org/10.1177/0959651818757877.
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Brake by wire that allows a number of braking functions exists on commercial vehicles under the name electronic pneumatic braking system, which can improve braking comfort and safety of commercial vehicle. The design of braking force distribution control method has drawn much more attention. Considering structure characteristics of electronic pneumatic braking system, a control method with a three-layer hierarchical structure is proposed. The first layer presents an estimation method towards vehicle mass and centre of gravity combining Kalman filter with recursive least square. The second layer is developed by designing a fixed relationship between the brake pedal displacement and vehicle braking deceleration. A deceleration control method that only uses brake pedal displacement as input is applied to make the vehicle follow the desired deceleration. The third layer includes a braking force distribution control method between the front and rear axles. The vehicle deceleration can be achieved with a smooth axle load transfer process based on linear matrix inequality. In addition, the controllers of wheel slip rate and valve hysteresis compensation are designed to improve control accuracy and efficiency. Utilizing a hardware-in-the-loop simulation test rig of electronic pneumatic braking system, the experiment results show that the control method can improve the braking performance of vehicle.
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Jiang, Lei. „Modeling of Linear Displacement and Design of Adaptive Robust Controller“. Mathematical Problems in Engineering 2020 (16.11.2020): 1–18. http://dx.doi.org/10.1155/2020/7014526.
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Twisted-string actuation method has attracted much more attention due to its compact size and considerable output force. Many studies have been proposed to estimate its linear displacement of actuation based on the angular measurement of the rotary device. However, the estimated results are not always accurate, which requires an additional process to make the estimation accuracy. In this paper, an ARC control scheme with force feedback has been developed for a high-accuracy twisted-string actuation system.
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Choi, Kyujeong, Jooseon Oh, Heung-Sub Kim, Hyun-Woo Han, Jung-Ho Park, Geun-Ho Lee, Jaho Seo und Young-Jun Park. „Experimental Study on the Dynamic Characteristics of Hydro-Pneumatic Semi-Active Suspensions for Agricultural Tractor Cabins“. Applied Sciences 10, Nr. 24 (16.12.2020): 8992. http://dx.doi.org/10.3390/app10248992.
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This study aims to establish a test method to obtain the dynamic characteristics of hydraulic-pneumatic semi-active suspensions used in tractor cabins. Because dynamic characteristics are utilized in simulation models for developing suspension control logic and must be secured to improve control performance, an accurate test method must be established. The dynamic characteristics of the suspension, i.e., the spring constant and damping coefficient, were obtained by changing the current and velocity conditions. An exciter was used as a test device to control the displacement and velocity of the hydraulic cylinder. In order to derive the spring constant of the suspension, a low-speed reciprocating motion test was performed to obtain the force-displacement diagram and to derive the damping coefficient; 48 tests were performed under 6 velocity conditions and 8 current conditions to obtain a force-velocity diagram for each result. The spring constant of the suspension was confirmed using the slope of the trend line in the force-displacement diagram obtained through the low-speed reciprocating motion test of the suspension. In addition, the damping coefficient was calculated using the force-velocity diagram obtained through the reciprocating motion test of the suspension under various current and velocity conditions.
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Cao, Yang, Ming Zong und Jing Zhang. „Electromagnetic Force Modelling for Hybrid Magnetic Bearing“. Advanced Materials Research 383-390 (November 2011): 7428–32. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.7428.
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In this paper, a novel structure of hybrid magnetic bearing with PM bias and inductance displacement sensor is proposed. The operating principle of the hybrid magnetic bearing with PM bias is introduced. The Electromagnetic Force Model is built in the paper, which is useful for the hybrid magnetic bearing control. An example is given. The analysis of finite element method shows that the structure of the hybrid magnetic bearing with PM bias proposed in the paper is feasible and the calculation method for hybrid magnetic circuit is correct.
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Lei, Jingtao, Gongliang Zheng, Lei Hu, Lihai Zhang und Tianmiao Wang. „External force estimation of fracture reduction robot based on force residual method“. International Journal of Advanced Robotic Systems 17, Nr. 1 (01.01.2020): 172988141989747. http://dx.doi.org/10.1177/1729881419897470.
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Robot-assisted fracture reduction surgery should be highly safe and accurate. It is necessary to accurately determine and control the reduction force of the reduction robot. In this article, a fracture reduction robot is designed with the configuration of the 6-universal-prismatic-universal (6-UPU). The vector method is used to analyze the kinematics of the reduction robot. The Jacobian matrix of the reduction robot and the second-order influence coefficient matrix of the acceleration are obtained. The Lagrangian method is adopted to analyze the dynamic of the reduction robot. The muscle contraction force of the femoral shaft fracture is analyzed based on the Hill model to determine the fracture reduction force. According to changing of the reduction force during the fracture reduction operation, a kind of external force estimation method based on force residual analysis is proposed. When there is no external force sensor at the end of the reduction robot, this method can be used to detect the reduction force in real time. According to the displacement, velocity, and output torque of each branch chain, the reduction force during the reduction operation of the reduction robot can be estimated. A simulation system is conducted and the simulation results show that the fracture reduction force can be estimated and accurately tracked in real time, which is of great significance for the safe operation of the fracture reduction robot.
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Ma, Yanhua, Xueqian Chen und Wenjie Zuo. „Equivalent static displacements method for contact force optimization“. Structural and Multidisciplinary Optimization 62, Nr. 1 (30.01.2020): 323–36. http://dx.doi.org/10.1007/s00158-020-02500-y.
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Bu, Wenshao, Biao Li und Chunxiao Lu. „Decoupling Control Strategy of BLIM considering Rotor Mass Eccentricity“. Journal of Control Science and Engineering 2018 (30.10.2018): 1–9. http://dx.doi.org/10.1155/2018/9579125.
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A BLIM, i.e., bearingless induction motor, is a multivariable, nonlinear, and strong coupling object; to achieve its high performance magnetic suspension operation control and overcome the influence of the rotor mass eccentricity, a decoupling control strategy considering the rotor mass eccentricity is proposed. Firstly, the mathematical model of the torque system based on the rotor flux orientation and the mathematical model of the magnetic suspension system based on the air gap flux orientation are presented; on this basis, the inverse system decoupling control method of the BLIM is researched. Then, according to the frequency characteristics of the unbalanced displacement, an unbalance vibration compensator is designed, which can generate a compensation force to suppress or eliminate the unbalanced displacement. Simulation experimental results have shown that the decoupling control among the rotor flux-linkage, motor speed, and two radial displacement components can be achieved; in the steady state, the unbalanced displacement can be basically eliminated, while, during the mutation process of motor speed, the unbalanced displacement can be suppressed effectively.
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Zazulak, Bohdanna T., Timothy E. Hewett, N. Peter Reeves, Barry Goldberg und Jacek Cholewicki. „Deficits in Neuromuscular Control of the Trunk Predict Knee Injury Risk“. American Journal of Sports Medicine 35, Nr. 7 (Juli 2007): 1123–30. http://dx.doi.org/10.1177/0363546507301585.
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Background Female athletes are at significantly greater risk of anterior cruciate ligament (ACL) injury than male athletes in the same high-risk sports. Decreased trunk (core) neuromuscular control may compromise dynamic knee stability. Hypotheses (1) Increased trunk displacement after sudden force release would be associated with increased knee injury risk; (2) coronal (lateral), not sagittal, plane displacement would be the strongest predictor of knee ligament injury; (3) logistic regression of factors related to core stability would accurately predict knee, ligament, and ACL injury risk; and (4) the predictive value of these models would differ between genders. Study Design Cohort study (prognosis); Level of evidence, 2. Methods In this study, 277 collegiate athletes (140 female and 137 male) were prospectively tested for trunk displacement after a sudden force release. Analysis of variance and multivariate logistic regression identified predictors of risk in athletes who sustained knee injury. Results Twenty-five athletes (11 female and 14 male) sustained knee injuries over a 3-year period. Trunk displacement was greater in athletes with knee, ligament, and ACL injuries than in uninjured athletes (P < .05). Lateral displacement was the strongest predictor of ligament injury (P = .009). A logistic regression model, consisting of trunk displacements, proprioception, and history of low back pain, predicted knee ligament injury with 91% sensitivity and 68% specificity (P = .001). This model predicted knee, ligament, and ACL injury risk in female athletes with 84%, 89%, and 91% accuracy, but only history of low back pain was a significant predictor of knee ligament injury risk in male athletes. Conclusions Factors related to core stability predicted risk of athletic knee, ligament, and ACL injuries with high sensitivity and moderate specificity in female, but not male, athletes.
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Bocko, Jozef, und Pavol Lengvarský. „Application of Finite Element Method for Analysis of Nanostructures“. Acta Mechanica et Automatica 11, Nr. 2 (01.06.2017): 116–20. http://dx.doi.org/10.1515/ama-2017-0018.
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AbstractThe paper deals with application of the finite element method in modelling and simulation of nanostructures. The finite element model is based on beam elements with stiffness properties gained from the quantum mechanics and nonlinear spring elements with force-displacement relation are gained from Morse potential. Several basic mechanical properties of structures are computed by homogenization of nanostructure, e.g. Young's modulus, Poisson's ratio. The problems connecting with geometrical parameters of nanostructures are considered and their influences to resulting homogenized quantities are mentioned.
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Ma, Qian Ying, She Liang Wang, Jun Qiang Zhu und Er Gang Xiong. „The Spatial Intelligent Structural Active Control Experimental Research“. Applied Mechanics and Materials 336-338 (Juli 2013): 551–55. http://dx.doi.org/10.4028/www.scientific.net/amm.336-338.551.
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Active control in the application has more and more research, the independent modal space control method is transform the system equation into modal coordinates, then obtain the internal decoupling equations express by modal coordinates, and based on control algorithm calculate the modal control force, which achieve real-time control effect. The control calculation method is simple and efficient to meet the needs of active control. The paper introduce modal control theory and implement methods, design and manufacture the piezoelectric driving lever based on the working principle of the piezoelectric pile, then through the test, give the voltage-driving force relationship, which is linear. An active control experiment on a three-layer intelligence space structure had been done, it can be seen that through the active control, the corresponding modal displacement and acceleration of the structures control are a lot of inhibition; at the same time, through spectral analysis, it can be seen the structured modal damping coefficient corresponding to varying degrees have been improved.
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Wang, Gongxian, Yang-Yang Wang, Jianming Yuan, Yi Yang und Dong Wang. „Arc-Surfaced Frictional Damper for Vibration Control in Container Crane“. Shock and Vibration 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/3675470.
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In this paper, a new arc-surfaced frictional damper (AFD) is proposed and its hysteretic behavior is experimentally studied. Then the device is applied to container crane based on a seesaw mechanism. The major advantage of the seesaw damping system is that the long tension cables can be utilized as bracing between the seesaw member and the portal legs to avoid compression and buckling of the cables. A simplified trilinear force-displacement model on the basis of experimental results is adopted to represent the hysteretic behavior of AFD. After that, seismic responses of container crane with and without dampers to four earthquakes are studied using nonlinear dynamic time-history analysis. Besides this system, a diagonal-brace-AFD system is studied for comparison. A method based on the displacement and energy dissipation ratio is proposed to find the optimum slip force for seesaw damping system. Performance of AFD control system is assessed though various parameters including displacement and maximum portal frame drift angle. Results prove a feasible application of AFD control system to absorb large amounts of seismic energy and significantly reduce the structural responses.