Articles de revues : « Collision optimization »

1

Xu, Qingyang, Chuang Zhang et Ning Wang. « Multiobjective Optimization Based Vessel Collision Avoidance Strategy Optimization ». Mathematical Problems in Engineering 2014 (2014) : 1–9. http://dx.doi.org/10.1155/2014/914689.

Texte intégral

Résumé :

The vessel collision accidents cause a great loss of lives and property. In order to reduce the human fault and greatly improve the safety of marine traffic, collision avoidance strategy optimization is proposed to achieve this. In the paper, a multiobjective optimization algorithm NSGA-II is adopted to search for the optimal collision avoidance strategy considering the safety as well as economy elements of collision avoidance. Ship domain and Arena are used to evaluate the collision risk in the simulation. Based on the optimization, an optimal rudder angle is recommended to navigator for collision avoidance. In the simulation example, a crossing encounter situation is simulated, and the NSGA-II searches for the optimal collision avoidance operation under the Convention on the International Regulations for Preventing Collisions at Sea (COLREGS). The simulation studies exhibit the validity of the method.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Li, Jinxin, Hongbo Wang, Wei Zhao et Yuanyuan Xue. « Ship’s Trajectory Planning Based on Improved Multiobjective Algorithm for Collision Avoidance ». Journal of Advanced Transportation 2019 (9 avril 2019) : 1–12. http://dx.doi.org/10.1155/2019/4068783.

Texte intégral

Résumé :

With vigorous development of the maritime trade, many intelligent algorithms have been proposed to avoid collisions due to resulting casualties and increased costs. According to the international regulations for preventing collisions at sea (COLREGs) and the self-evolution ability of the intelligent algorithm, the collision avoidance trajectory can be more consistent with the requirements of reality and maritime personnel. In this paper, the optimization of ship collision avoidance strategies is realized by both an improved multiobjective optimization algorithm NSGA-II and the ship domain under the condition of a wide sea area without any external disturbances. By balancing the safety and economy of ship collision avoidance, the avoidance angle and the time to the action point are used as the variables encoded by the algorithm, and the fuzzy ship domain is used to calculate the collision avoidance risk to achieve collision avoidance. The simulation results show that the proposed method can optimize the ship collision avoidance strategy and provide a reasonable scheme for ship navigation.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Mohamed, Abdulrahman. « Novel approach for anti-collision planning optimization in directional wells ». International Journal of Engineering & ; Technology 9, n^o 2 (3 avril 2020) : 333. http://dx.doi.org/10.14419/ijet.v9i2.30306.

Texte intégral

Résumé :

One of the most application of the directional drilling is drilling multiple wells from one location or platform. In drilling multiple wells from one location the major problem that faced is avoiding the collision with the offset wells that drilled near the proposed well in the same region. Therefore, the Potential of Collison between the wells can cause severe catastrophic accidents such as an explosion or oil spill. Several measurements of proximity calculation or methods have been adopted to control the distance between the wells, avoid the Collison, increas-ing the clearance along with smoothing the trajectory, Reducing the drilling time based on the anti-collision rules. A real case study of an offshore directional horizontal well drilled from the platform is studied through the paper. The proposed well is drilled in the neighboring of three Offset wells that should be Planned completely to avoid the Collison with them. The well is planned through an advanced anti-collision method that results in preventing the collision of well with optimized drilling performance through Oriented separation factor (OSF). This factor yields appropriate separation with OSF greater than 5. This yield efficient separation with offset well 1, offset well 2 and offset well 3 greater thant5, In addition to optimized drilling performance of 84% drilling versus 16% sliding that results in the completion of the well in 50 days with positive income that result in 8.55 Return on Investment (ROI).

Styles APA, Harvard, Vancouver, ISO, etc.

4

Ma, Wen Yao, et Jia Xuan Yang. « Collision Avoidance Strategy Optimization of Ship’s Speed Alteration with Bacterial Foraging Algorithm ». Applied Mechanics and Materials 278-280 (janvier 2013) : 1318–22. http://dx.doi.org/10.4028/www.scientific.net/amm.278-280.1318.

Texte intégral

Résumé :

When ship navigates at sea, collision avoidance of ship’s speed alteration is frequently adopted by officer on watch in order to prevent from forming collision situation with target ship(s). Bacterial foraging algorithm (BFA) that imitates the social foraging behavior of Escherichia coli is an optimal search method suitable for complex problems. This research adopts the bacterial foraging algorithm to find the speed alteration collision avoidance strategy from an economical viewpoint, combining the international regulations for preventing collisions at sea (COLREGS) and the safety domain of ship. An optimal time of changing speed, amplitude of speed alteration and navigation restoration time will also be provided. The effectiveness of the algorithm has been verified by simulation. The study offers new thinking and a practical method for collision avoidance decision.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Lazarowska, Agnieszka. « Safe Ship Control Method with the Use of Ant Colony Optimization ». Solid State Phenomena 210 (octobre 2013) : 234–44. http://dx.doi.org/10.4028/www.scientific.net/ssp.210.234.

Texte intégral

Résumé :

Nowadays Integrated Bridge Systems are applied on board a ship to increase safety of navigation. These systems consist of many electronic devices such as radar, ECDIS and autopilot, which aid the deck officer in the process of conducting navigation. Despite that, ship accidents caused by human error still occur. The paper presents new method of safe ship control in collision situations. Ant Colony Optimization is applied to determine safe ship trajectory. Developed algorithm is applicable for situations in restricted waters, where most of collision situations occur. International Regulations for Preventing Collisions at Sea (COLREGs) are taken into consideration in the process of solution construction. The task of collision avoidance at sea is defined as dynamic optimization problem with the use of static and dynamic constraints. Static constraints are represented by lands, canals, shallows, fairways, while other ships constitute dynamic constraints. Described method was implemented in MATLAB programming language. Performed simulation tests results of encounter situations with one target ship as well as with many target vessels are presented. Received solutions confirm successful application of this method to the problem of ships collisions avoidance. Developed algorithm deals also with more complex situations. This new algorithm is planned to be implemented in anti-collision decision support system on board a ship, what would contribute to enhance safety of maritime transport.

Styles APA, Harvard, Vancouver, ISO, etc.

6

Xia, Guoqing, Zhiwei Han, Bo Zhao et Xinwei Wang. « Local Path Planning for Unmanned Surface Vehicle Collision Avoidance Based on Modified Quantum Particle Swarm Optimization ». Complexity 2020 (13 avril 2020) : 1–15. http://dx.doi.org/10.1155/2020/3095426.

Texte intégral

Résumé :

An unmanned surface vehicle (USV) plans its global path before the mission starts. When dynamic obstacles appear during sailing, the planned global path must be adjusted locally to avoid collision. This study proposes a local path planning algorithm based on the velocity obstacle (VO) method and modified quantum particle swarm optimization (MQPSO) for USV collision avoidance. The collision avoidance model based on VO not only considers the velocity and course of the USV but also handles the variable velocity and course of an obstacle. According to the collision avoidance model, the USV needs to adjust its velocity and course simultaneously to avoid collision. Due to the kinematic constraints of the USV, the velocity window and course window of the USV are determined by the dynamic window approach (DWA). In summary, local path planning is transformed into a multiobjective optimization problem with multiple constraints in a continuous search space. The optimization problem is to obtain the USV’s optimal velocity variation and course variation to avoid collision and minimize its energy consumption under the rules of the International Regulations for Preventing Collisions at Sea (COLREGs) and the kinematic constraints of the USV. Since USV local path planning is completed in a short time, it is essential that the optimization algorithm can quickly obtain the optimal value. MQPSO is primarily proposed to meet that requirement. In MQPSO, the efficiency of quantum encoding in quantum computing and the optimization ability of representing the motion states of the particles with wave functions to cover the whole feasible solution space are combined. Simulation results show that the proposed algorithm can obtain the optimal values of the benchmark functions and effectively plan a collision-free path for a USV.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Machmudah, Affiani, et Setyamartana Parman. « Bezier Curve Collision-Free Route Planning Using Meta-Heuristic Optimization ». International Journal of Artificial Intelligence & ; Robotics (IJAIR) 3, n^o 1 (31 mai 2021) : 1–14. http://dx.doi.org/10.25139/ijair.v3i1.3821.

Texte intégral

Résumé :

A collision-free route is very important for achieving sustainability in a manufacturing process and vehicle robot trajectories that commonly operate in a hazardous environment surrounded by obstacles. This paper presents a collision avoidance algorithm using a Bezier curve as a route path. The route planning is modeled as an optimization problem with the objective optimization is to minimize the route length considering an avoiding collision constraint. The collision-avoidance algorithm based on curve point analysis is developed incorporating metaheuristic optimizations, namely a Genetic Algorithm (GA) and a Grey Wolf Optimizer (GWO). In the collision avoidance algorithm, checking of curve point's position is important to evaluate the individual fitness value. The curve points are analyzed in such a way so that only the paths which are outside the obstacle area are selected. In this case, besides the minimum length as a fitness function, the constraint is the position of curve points from an obstacle. With the help of meta-heuristic optimization, the developed collision avoidance algorithm has been applied successfully to different types of obstacle geometries. The optimization problem is converted to the maximization problem so that the highest fitness value is used to measure the performance of the GA and GWO. In general, results show that the GWO outperforms the GA, where it exhibits the highest fitness value. However, the GA has shown better performance for the narrow passage problem than that of the GWO. Thus, for future research, implementing the hybrid technique combining the GA and the GWO to solve the advanced path planning is essential.

Styles APA, Harvard, Vancouver, ISO, etc.

8

Custură-Crăciun, Dan, Daniel Cochior et Corneliu Neagu. « Optimization of Collision Detection in Surgical Simulations ». ACTA Universitatis Cibiniensis 64, n^o 1 (1 novembre 2014) : 34–39. http://dx.doi.org/10.2478/aucts-2014-0007.

Texte intégral

Résumé :

Abstract Just like flight and spaceship simulators already represent a standard, we expect that soon enough, surgical simulators should become a standard in medical applications. A simulations quality is strongly related to the image quality as well as the degree of realism of the simulation. Increased quality requires increased resolution, increased representation speed but more important, a larger amount of mathematical equations. To make it possible, not only that we need more efficient computers, but especially more calculation process optimizations. A simulator executes one of the most complex sets of calculations each time it detects a contact between the virtual objects, therefore optimization of collision detection is fatal for the work-speed of a simulator and hence in its quality

Styles APA, Harvard, Vancouver, ISO, etc.

9

Liu, Jiang, Bai Gen Cai, Yun Peng Wang et Jian Wang. « Simulation Analysis of a PSO-Based Vehicle Collision Avoidance Method under Cooperative Vehicle Infrastructure Environment ». Applied Mechanics and Materials 241-244 (décembre 2012) : 1539–44. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.1539.

Texte intégral

Résumé :

Vehicle safety is of great importance to improve the capability and performance of the transportation system. To deal with safety threats most probably caused by the vehicle collisions in unsignalized intersections, concept of vehicle infrastructure cooperation provides a perspective and challenging solution to enable sufficient information interaction by V2V and V2I communication, which make it feasible to avoid collisions more autonomously. In vehicle collision avoidance scheme, decision making of vehicle braking control is crucial for emergent situations when safety alerts are not reacted by the driver. In this paper, a novel cooperative vehicle collision avoidance method based on particle swarm optimization is proposed, with an integrated fitness updating criteria considering both safety interval and relative continuity of vehicle deceleration. With a simulation analysis approach, the proposed collision avoiding solution is validated in a real road oriented scenario, and the results demonstrate its effectiveness and advantages to reduce collision and achieve safety assurance under cooperative vehicle infrastructure environment.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Zheng, Yisong, Xiuguo Zhang, Zijing Shang, Siyu Guo et Yiquan Du. « A Decision-Making Method for Ship Collision Avoidance Based on Improved Cultural Particle Swarm ». Journal of Advanced Transportation 2021 (15 janvier 2021) : 1–31. http://dx.doi.org/10.1155/2021/8898507.

Texte intégral

Résumé :

In the process of ship collision avoidance decision making, steering collision avoidance is the most frequently adopted collision avoidance method. In order to obtain an effective and reasonable steering angle, this paper proposes a decision-making method for ship collision avoidance based on improved cultural particle swarm. Firstly, the ship steering angle direction is to be determined. In this stage, the Kalman filter is used to predict the ship’s trajectory. According to the prediction parameters, the collision risk index of the ship is calculated and the situation with the most dangerous ship is judged. Then, the steering angle direction of the ship is determined by considering the Convention on the International Regulations for Preventing Collisions at Sea (COLREGs). Secondly, the ship steering angle is to be calculated. In this stage, the cultural particle swarm optimization algorithm is improved by introducing the index of population premature convergence degree to adaptively adjust the inertia weight of the cultural particle swarm so as to avoid the algorithm falling into premature convergence state. The improved cultural particle swarm optimization algorithm is used to find the optimal steering angle within the range of the steering angle direction. Compared with other evolutionary algorithms, the improved cultural particle swarm optimization algorithm has better global convergence. The convergence speed and stability are also significantly improved. Thirdly, the ship steering angle direction decision method in the first stage and the ship steering angle decision method in the second stage are integrated into the electronic chart platform to verify the effectiveness of the decision-making method of ship collision avoidance presented in this paper. Results show that the proposed approach can automatically realize collision avoidance from all other ships and it has an important practical application value.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Zhao, Wen Ge. « RFID Anti-Collision Method Based on Particle Swarm Optimization and Support Vector Machine ». Applied Mechanics and Materials 170-173 (mai 2012) : 3398–401. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.3398.

Texte intégral

Résumé :

RFID anti-collision method based on particle swarm optimization and support vector machine is presented in the paper. Support vector machine is a new detection technology,which is applied to RFID anti-collision detection. Particle swarm optimization algorithm is applied to choose the appropriate parameters of support vector machine. Particle swarm optimization algorithm can make the particle move toward the optimal resolution based on the history best experiences of each particle and global best position in swarm.The proposed RFID anti-collision structure is mainly composed of protocol processing module, interface module, RFID anti-collision method and serial-parallel conversion.The testing results show that RFID collision detection accuracy of particle swarm optimization and support vector machine than that of traditional support vector machine and BP neural network.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Wang, Xuewu, Lika Xue, Yixin Yan et Xingsheng Gu. « Welding Robot Collision-Free Path Optimization ». Applied Sciences 7, n^o 2 (8 février 2017) : 89. http://dx.doi.org/10.3390/app7020089.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

13

İNAN, Timur, et Ahmet Fevzi BABA. « Particle swarm optimization-based collision avoidance ». TURKISH JOURNAL OF ELECTRICAL ENGINEERING & ; COMPUTER SCIENCES 27, n^o 3 (15 mai 2019) : 2137–55. http://dx.doi.org/10.3906/elk-1808-63.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

14

Wang, Pangwei, WenXiang Wu, Xiaohui Deng, Lin Xiao, Li Wang et Min Li. « Novel Cooperative Collision Avoidance Model for Connected Vehicles ». Transportation Research Record : Journal of the Transportation Research Board 2645, n^o 1 (janvier 2017) : 144–56. http://dx.doi.org/10.3141/2645-16.

Texte intégral

Résumé :

Connected vehicle technology exchanges real-time vehicle and traffic information through vehicle-to-vehicle and vehicle-to-infrastructure communication. The technology has the potential to improve traffic safety applications such as collision avoidance. In this paper, a novel cooperative collision avoidance (CCA) model that could improve the effectiveness of the collision avoidance system of connected vehicles was developed. Unlike traditional collision avoidance models, which relied mainly on emergency braking, the proposed CCA approach avoided collision through a combination of following vehicle deceleration and leading vehicle acceleration. Through spacing policy theory and nonlinear optimization, the model calculated the desired deceleration rate for the following vehicle and the acceleration rate for the leading vehicle, respectively, at each time interval. The CCA approach was then tested on a scaled platform with hardware-in-the-loop simulation embedded with MATLAB/Simulink and a car simulator package, CarSim. Results show that the proposed model can effectively avoid rear-end collisions in a three-vehicle platoon.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Tai, Qian, et Xiao Yu Zhang. « Research and Application on Automotive Aluminum Bumper Based on Topology Optimization ». Applied Mechanics and Materials 189 (juillet 2012) : 495–99. http://dx.doi.org/10.4028/www.scientific.net/amm.189.495.

Texte intégral

Résumé :

Based on the explicit dynamic finite element analysis software, the use of hybrid cellular automata (HCA) as an optimization model, the collision of beams in the aluminum front structure optimization design. The 6061 aluminum alloy before the collision of beams to replace a model of the original steel beams, trolley collision simulation and experimental validation of the results show that the aluminum front impact beams than the original steel before the collision beam quality to reduce by 25% and has a higher flexural strength, low-speed collision, aluminum front impact beams than the original steel system energy absorption increased by 45.6%.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Liu, Jun, et Yong Yang. « Structural Optimization Design of Flexible Anti-Collision Device for Bridge ». Applied Mechanics and Materials 201-202 (octobre 2012) : 649–52. http://dx.doi.org/10.4028/www.scientific.net/amm.201-202.649.

Texte intégral

Résumé :

Due to he complexity of the shipping collision process, the design of the protection device can not be accurately calculated by theoretical formula. Through the establishment of the anti-collision device in simplified model, this paper carries out the simulation analysis of the finite element values, and studies the key parameters that affects the performance of the anti-collision device: the geometric structure of inside and outside of steel, the combination of anti-collision circle (elastic element), the flexural rigidity of peripheral steel. And then we get the design parameters of the equivalent flexural rigidity of peripheral steel which is to ensure the that the peripheral steel won’t be partial collapse when there are some collision between some representative ships and it; and we also find that the appropriate increase in the flexural rigidity of around the vertex of the outer steel will improve the overall anti-collision ability of the anti-collision device.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Hauser, Kris. « Semi-infinite programming for trajectory optimization with non-convex obstacles ». International Journal of Robotics Research 40, n^o 10-11 (10 janvier 2021) : 1106–22. http://dx.doi.org/10.1177/0278364920983353.

Texte intégral

Résumé :

This article presents a novel optimization method that handles collision constraints with complex, non-convex 3D geometries. The optimization problem is cast as a semi-infinite program in which each collision constraint is implicitly treated as an infinite number of numeric constraints. The approach progressively generates some of these constraints for inclusion in a finite nonlinear program. Constraint generation uses an oracle to detect points of deepest penetration, and this oracle is implemented efficiently via signed distance field (SDF) versus point cloud collision detection. This approach is applied to pose optimization and trajectory optimization for both free-flying rigid bodies and articulated robots. Experiments demonstrate performance improvements compared with optimizers that handle only convex polyhedra, and demonstrate efficient collision avoidance between non-convex CAD models and point clouds in a variety of pose and trajectory optimization settings.

Styles APA, Harvard, Vancouver, ISO, etc.

18

GAVRILOVA, MARINA L., et JON ROKNE. « COLLISION DETECTION OPTIMIZATION IN A MULTI-PARTICLE SYSTEM ». International Journal of Computational Geometry & ; Applications 13, n^o 04 (août 2003) : 279–301. http://dx.doi.org/10.1142/s0218195903001189.

Texte intégral

Résumé :

Collision detection optimization in an event-driven simulation of a multi-particle system is one of the crucial tasks, determining the efficiency of the simulation. We present the event-driven simulation algorithm that employs dynamic computational geometry data structures as a tool for collision detection optimization (CDO). The first successful application of the dynamic generalized Voronoi diagram method for collision detection optimization in a system of moving particles is discussed. A comprehensive comparision of four kinetic data structures in d-dimensional space, performed in a framework of an event-driven simulation of a granular-type materials system, is supported by the experimental results.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Borzabadi. « Collision-Free Trajectory Optimization of Robot Manipulators ». Journal of Advanced Research in Applied Mathematics 2, n^o 1 (1 mars 2010) : 64–75. http://dx.doi.org/10.5373/jaram.236.100809.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

20

Yan, Fu Yu, Fan Wu, Fei Peng et Zhi Jie Zhu. « On Improving Path Clearance Optimization Method for Motion Planning ». Advanced Materials Research 926-930 (mai 2014) : 3128–31. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.3128.

Texte intégral

Résumé :

The efficiency of path clearance optimization method is low and the corresponding path may collide with obstacles when applying it to the original path planned by RRTConCon algorithm. The paper analyzed the original path clearance and corridor width and chose proper moving distance towards the medial axis and binary search step. The paper also analyzed the collision reason and proposed an method to deal with it. The method moves collision configurations to the free space and retracts them to the medial axis, then adds them to the retracted path. The experimental results showed the measures are effective to improve efficiency and could deal with collision problem.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Zhao, Wei, et Fei Li. « Collision Detection Based on Surface Simplification and Particle Swam Optimization ». Advanced Materials Research 267 (juin 2011) : 476–81. http://dx.doi.org/10.4028/www.scientific.net/amr.267.476.

Texte intégral

Résumé :

We present an efficient stochastic collision detection based on surface simplification and particle swam optimization (PSO). In this framework, first, the search space is reduced by surface simplification during the pre-process and then the interference triangles are gained by PSO. This framework takes the surface simplification’s advantage of decreasing the triangles dramatically with little geometry error. In order to handle every collision detection step, we use surface simplification and PSO, by which user not only can balance performance and detection quality, but also increase the speed of collision detection.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Xiao, Shan Hua, Wen Chao Zhou et Gui Xing Fu. « Five-Axis Machining and Impeller Vericut Simulation Optimization ». Applied Mechanics and Materials 401-403 (septembre 2013) : 155–58. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.155.

Texte intégral

Résumé :

Analysis impeller axis CNC machining process and processing content, applications Master CAM X6 software to generate a five-axis roughing trajectory of the impeller, the impeller expansion tank and wheels finishing trajectory, blade finishing trajectory. Vericut simulation software tool set, add the tool library, add rough, add impeller machining CNC program, set collision and interference color display, program optimization parameters, simulation of collision-free, without undercutting the five-axis impeller.

Styles APA, Harvard, Vancouver, ISO, etc.

23

Song, Yuho, et Kunsoo Huh. « Driving and steering collision avoidance system of autonomous vehicle with model predictive control based on non-convex optimization ». Advances in Mechanical Engineering 13, n^o 6 (juin 2021) : 168781402110276. http://dx.doi.org/10.1177/16878140211027669.

Texte intégral

Résumé :

A planar motion control system is proposed for autonomous vehicles not only to follow the lanes, but also to avoid collisions by braking, accelerating, and steering. The supervisor is designed first to determine the desired speed and the risk of the maneuvering due to road boundaries and obstacles. In order to allow lane changes on multi-lane roads, the model predictive controller is formulated based on the probabilistic non-convex optimization. The micro-genetic algorithm is applied to calculate the target speed and target steering angle in real time. A software-in-the-loop unit is constructed with the Rapid Control Prototyping device in the vehicle communication environment. The performance of the proposed system is verified for various collision avoidance scenarios and the simulation results demonstrate the safe and effective driving performance of autonomous vehicles with no collision on multi-lane road.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Wang, Xingzhong, Xinghua Kou, Jinfeng Huang et Xianchun Tan. « A Collision Avoidance Method for Intelligent Ship Based on the Improved Bacterial Foraging Optimization Algorithm ». Journal of Robotics 2021 (9 février 2021) : 1–10. http://dx.doi.org/10.1155/2021/6661986.

Texte intégral

Résumé :

The bacterial foraging optimization algorithm (BFOA) is an intelligent population optimization algorithm widely used in collision avoidance problems; however, the BFOA is inappropriate for the intelligent ship collision avoidance planning with high safety requirements because BFOA converges slowly, optimizes inaccurately, and has low stability. To fix the above shortcomings of BFOA, an autonomous collision avoidance algorithm based on the improved bacterial foraging optimization algorithm (IBFOA) is demonstrated in this paper. An adaptive diminishing fractal dimension chemotactic step length is designed to replace the fixed step length to achieve the adaptive step length adjustment, an optimal swimming search method is proposed to solve the invalid searching and repeated searching problems of the traditional BFOA, and the adaptive migration probability is developed to take the place of the fixed migration probability to prevent elite individuals from being lost in BOFA. The simulation of benchmark tests shows that the IBFOA has a better convergence speed, optimized accuracy, and higher stability; according to a collision avoidance simulation of intelligent ships which applies the IBFOA, it can realize the autonomous collision avoidance of intelligent ships in dynamic obstacles environment is quick and safe. This research can also be used for intelligent collision avoidance of automatic driving ships.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Kempe, Tobias, et Jochen Fröhlich. « Collision modelling for the interface-resolved simulation of spherical particles in viscous fluids ». Journal of Fluid Mechanics 709 (23 août 2012) : 445–89. http://dx.doi.org/10.1017/jfm.2012.343.

Texte intégral

Résumé :

AbstractThe paper presents a model for particle–particle and particle–wall collisions during interface-resolving numerical simulations of particle-laden flows. The accurate modelling of collisions in this framework is challenging due to methodological problems generated by interface approach and contact as well as due to the greatly different time scales involved. To cope with this situation, multiscale modelling approaches are introduced avoiding excessive local grid refinement during surface approach and time step reduction during the surface contact. A new adaptive model for the normal forces in the phase of ‘dry contact’ is proposed, stretching the collision process in time to match the time step of the fluid solver. This yields a physically sound and robust collision model with modified stiffness and damping determined by an optimization scheme. Furthermore, the model is supplemented with a new approach for modelling the tangential force during oblique collisions which is based on two material parameters: a critical impact angle separating rolling from sliding and the friction coefficient for the sliding motion. The resulting new model is termed the adaptive collision model (ACM). All proposed sub-models only contain physical parameters, and virtually no numerical parameters requiring adjustment or tuning. The new model is implemented in the framework of an immersed boundary method but is applicable with any spatial and temporal discretization. Detailed validation against experimental data was performed so that a general and versatile model for arbitrary collisions of spherical particles in viscous fluids is now available.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Sokolovskij, Edgar, et Šarūnas Mikaliūnas. « MODELLING OF COLLISIONS OF THE AUTOMOBILES ». TRANSPORT 21, n^o 4 (31 décembre 2006) : 239–44. http://dx.doi.org/10.3846/16484142.2006.9638073.

Texte intégral

Résumé :

The graphic analytical modelling and the computer modelling of collisions of the automobiles are compared in this article. The examples of modelling of collisions of the automobiles are given. The computer modelling of collision of the automobiles with the help of the program PC CRASH is introduced. The possibilities and advantages of this computer program, the inserted parameters and their optimization are investigated. The possibilities of applying the computer modelling program in the experts’ examination of traffic accidents while modelling collisions of the automobiles, the items and requirements raised towards the experts, who work with such programs, on reliability of the obtained results are considered.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Man, Ran Ran, Dong Sheng Zhou et Qiang Zhang. « A Survey of Collision Detection ». Applied Mechanics and Materials 538 (avril 2014) : 360–63. http://dx.doi.org/10.4028/www.scientific.net/amm.538.360.

Texte intégral

Résumé :

The interference and collision detection problem among objects is widely studied in graphics, simulation, animation and virtual reality technologic. In this paper, we proceed from the main solution for collision detection, analyzed from graphic space, bounding volume hierarchies (BVH), Particle Swarm Optimization (PSO) and parallel algorithm, summarized the research situation about collision detection in recent years. At last, we give several suggestions to improve the efficiency and reliability of the collision detection algorithm.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Hedjar, Ramdane, et Messaoud Bounkhel. « An Automatic Collision Avoidance Algorithm for Multiple Marine Surface Vehicles ». International Journal of Applied Mathematics and Computer Science 29, n^o 4 (1 décembre 2019) : 759–68. http://dx.doi.org/10.2478/amcs-2019-0056.

Texte intégral

Résumé :

Abstract In recent years, unmanned surface vehicles have been widely used in various applications from military to civil domains. Seaports are crowded and ship accidents have increased. Thus, collision accidents occur frequently mainly due to human errors even though international regulations for preventing collisions at seas (COLREGs) have been established. In this paper, we propose a real-time obstacle avoidance algorithm for multiple autonomous surface vehicles based on constrained convex optimization. The proposed method is simple and fast in its implementation, and the solution converges to the optimal decision. The algorithm is combined with the PD-feedback linearization controller to track the generated path and to reach the target safely. Forces and azimuth angles are efficiently distributed using a control allocation technique. To show the effectiveness of the proposed collision-free path-planning algorithm, numerical simulations are performed.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Mote, Mark, Magnus Egerstedt, Eric Feron, Andrew Bylard et Marco Pavone. « Collision-Inclusive Trajectory Optimization for Free-Flying Spacecraft ». Journal of Guidance, Control, and Dynamics 43, n^o 7 (juillet 2020) : 1247–58. http://dx.doi.org/10.2514/1.g004788.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

30

Zhang, Jinfen, Xin Ping Yan, Di Zhang et S. Haugen. « Ship Trajectory Control Optimization in Anti-collision Maneuvering ». TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation 7, n^o 2 (2013) : 89–93. http://dx.doi.org/10.12716/1001.07.01.11.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

31

LEE, Seung-Je, et Hiroshi YAMAKAWA. « Trajectory Optimization of Flexible Manipulators for Collision-Free. » Transactions of the Japan Society of Mechanical Engineers Series C 66, n^o 644 (2000) : 1250–57. http://dx.doi.org/10.1299/kikaic.66.1250.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

32

Macklin, Miles, Kenny Erleben, Matthias Müller, Nuttapong Chentanez, Stefan Jeschke et Zach Corse. « Local Optimization for Robust Signed Distance Field Collision ». Proceedings of the ACM on Computer Graphics and Interactive Techniques 3, n^o 1 (18 avril 2020) : 1–17. http://dx.doi.org/10.1145/3384538.

Texte intégral

Résumé :

Signed distance fields (SDFs) are a popular shape representation for collision detection. This is due to their query efficiency, and the ability to provide robust inside/outside information. Although it is straightforward to test points for interpenetration with an SDF, it is not clear how to extend this to continuous surfaces, such as triangle meshes. In this paper, we propose a per-element local optimization to find the closest points between the SDF isosurface and mesh elements. This allows us to generate accurate contact points between sharp point-face pairs, and handle smoothly varying edge-edge contact. We compare three numerical methods for solving the local optimization problem: projected gradient descent, Frank-Wolfe, and golden-section search. Finally, we demonstrate the applicability of our method to a wide range of scenarios including collision of simulated cloth, rigid bodies, and deformable solids.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Tian, Bo, Wei Jie Gao et Qian Wang. « Studies on Ships Collision Avoidance with SAPSO Arithmetic ». Advanced Materials Research 971-973 (juin 2014) : 1338–42. http://dx.doi.org/10.4028/www.scientific.net/amr.971-973.1338.

Texte intégral

Résumé :

Vessel collision prevention issue has always been the focus of the nautical science research. This paper considers a variety of factors that affect the safety of the ship collision avoidance to optimize the research on multi-boat collision avoidance magnitude, by using the improved collision risk index model and simulated annealing particle swarm optimization. The result of the simulation indicates that SAPSO can deal with the problems of angle of avoiding collision, results are accurate and feasible.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Yang, Yunsik, Euy Sik Jeon et Dae Ho Park. « Optimization of Design Parameters of Spiral Spring for Active Headrest Deployment ». MATEC Web of Conferences 167 (2018) : 02017. http://dx.doi.org/10.1051/matecconf/201816702017.

Texte intégral

Résumé :

Several studies have been conducted to prevent neck injury in rear-end collision. The headrest of the seat which suppresses the relative motion of the head and the torso can suppress the extension of the head, thereby alleviating the injury. The active headrest has a mechanism that supports the head by deploying the headrest at the rear-end collision. The spring remains compressed or twisted until a collision signal is generated and the headrest is deployed after the collision signal. Depending on the shape and deployment structure of the spring, a spring design with a high resilience that is acceptable to the headrest is required. In this paper, design parameter of spiral spring suitable for the structure of the developed headrest is selected, prototypes are fabricated, and development parameters such as development time and development distance are checked and optimal design parameters of the spiral spring are derived. The feasibility of the headrest with the designed spiral spring was verified by the finite element analysis.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Kang, Liuwang, Ankur Sarker et Haiying Shen. « Velocity Optimization of Pure Electric Vehicles with Traffic Dynamics and Driving Safety Considerations ». ACM Transactions on Internet of Things 2, n^o 1 (février 2021) : 1–24. http://dx.doi.org/10.1145/3433678.

Texte intégral

Résumé :

As Electric Vehicles (EVs) become increasingly popular, their battery-related problems (e.g., short driving range and heavy battery weight) must be resolved as soon as possible. Velocity optimization of EVs to minimize energy consumption in driving is an effective alternative to handle these problems. However, previous velocity optimization methods assume that vehicles will pass through traffic lights immediately at green traffic signals. Actually, a vehicle may still experience a delay to pass a green traffic light due to a vehicle waiting queue in front of the traffic light. Also, as velocity optimization is for individual vehicles, previous methods cannot avoid rear-end collisions. That is, a vehicle following its optimal velocity profile may experience rear-end collisions with its frontal vehicle on the road. In this article, for the first time, we propose a velocity optimization system that enables EVs to immediately pass green traffic lights without delay and to avoid rear-end collisions to ensure driving safety when EVs follow optimal velocity profiles on the road. We collected real driving data on road sections of US-25 highway (with two driving lanes in each direction and relatively low traffic volume) to conduct extensive trace-driven simulation studies. Results show that our velocity optimization system reduces energy consumption by up to 17.5% compared with real driving patterns without increasing trip time. Also, it helps EVs to avoid possible collisions compared with existing collision avoidance methods.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Nayl, Thaker. « ROBOTIC MOTION PLANNING USING CONVEX OPTIMIZATION METHODS ». Iraqi Journal for Computers and Informatics 45, n^o 2 (1 décembre 2019) : 20–23. http://dx.doi.org/10.25195/ijci.v45i2.49.

Texte intégral

Résumé :

Collision avoidance techniques tend to derive the robot away of the obstacles in minimal total travel distance. Most ofthe collision avoidance algorithms have trouble get stuck in a local minimum. A new technique is to avoid local minimum in convexoptimization-based path planning. Obstacle avoidance problem is considered as a convex optimization problem under system state andcontrol constraints. The idea is by considering the obstacles as a convex set of points which represents the obstacle that encloses inminimum volume ellipsoid, also the addition of the necessary offset distance and the modified motion path is presented. In the analysis,the results demonstrated the effectiveness of the suggested motion planning by using the convex optimization technique.

Styles APA, Harvard, Vancouver, ISO, etc.

37

HOU, SHUJUAN, YUNA ZHENG, JINDE XIE et XU HAN. « OPTIMIZATION DESIGN OF NJ SHAPED GUARDRAIL BASED ON COLLISION SAFETY CONSIDERATION ». International Journal of Computational Methods 11, n^o 06 (décembre 2014) : 1350083. http://dx.doi.org/10.1142/s0219876213500837.

Texte intégral

Résumé :

Cross-sectional shapes and dimensions of concrete guardrails directly influence climbing angles and directions of a car when a collision between concrete guardrail and car occurs. At the same time, contacting and climbing angles and directions influence the peak crushing force and the peak acceleration of a car body during a collision. Therefore, cross-sectional shapes and dimensions of concrete guardrails can influence the severity of injuries sustained when a collision between concrete guardrail and car occurs. In this study, the passive safety of a car body is considered in optimizing the cross-sectional dimensions of a New Jersey (NJ) concrete guardrail based on numerical simulations and surrogate model techniques. Optimal Latin hypercube design is used to get sampling points, and multi-island genetic algorithm is utilized to obtain the optimal size of NJ concrete guardrail in the optimization process. After simulating the collision between car and optimal NJ shaped guardrail, the results show that the peak acceleration of optimal results reduces significantly by 28% compared with the initial value, and the peak interface force decreases from 378.6 kN to 241.5 kN.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Zhang, Long, Qing Xuan Jia, Gang Chen et Han Xu Sun. « A Genetic Algorithm Based Approach for Pre-Collision Trajectory Optimization with Multi-Targets ». Applied Mechanics and Materials 487 (janvier 2014) : 664–69. http://dx.doi.org/10.4028/www.scientific.net/amm.487.664.

Texte intégral

Résumé :

Aiming at on-orbit capture task, a Genetic Algorithm based approach for pre-collision trajectory optimization with multi-targets is proposed in this paper. Through the analysis of task characteristics, multi-targets before collision are presented, which contain the point-to-point manoeuvre, impact pose control and impact impulse minimization. Genetic algorithm is employed to optimize the pre-collision trajectory after integrating multi-targets by setting task weight. At last, the simulation results verify the effectiveness of the proposed method.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Jixiong, Li, et Wang Daoyong. « Study on application of MSOT method for lightweight design of automobile body structure ». Advances in Mechanical Engineering 12, n^o 10 (octobre 2020) : 168781402096504. http://dx.doi.org/10.1177/1687814020965049.

Texte intégral

Résumé :

In this study, the integrated MSOT (M-Multi-dimensional factor autobody model, S-Screening autobody component, O-Optimization of plate thickness, T-Testing, and validation) integration method is adopted to optimize the automobile body structure design for weight reduction. First, a multi-dimensional factor body model is established, then components of the vehicle are screened for the most important targets related to weight reduction and performance, and a multi-objective optimization is performed. Virtual experiments were carried out to validate the analysis and the MSOT method were proposed for lightweight design of the automobile body structure. A multi-dimensional performance model that considers stiffness, modality, strength, frontal offset collision, and side collision of a domestic passenger car body structure. Components affecting the weight of the vehicle were identified. Sheet metal thickness was selected as the main optimization target and a multi-objective optimization was carried out. Finally, simulations were performed on the body structure. The comprehensive performance, in terms of fatigue strength, frontal offset collision safety, and side collision safety, was verified using the optimized Pareto solution set. The results show that the established MSOT method can be used to comprehensively explore the weight reduction of the body structure, shorten the development process, and reduce development costs.

Styles APA, Harvard, Vancouver, ISO, etc.

40

Ahmed, Fatma, Nobuyuki Kawahara et Eiji Tomita. « Binary collisions and coalescence of droplets in low-pressure fuel injector ». Thermal Science, n^o 00 (2020) : 185. http://dx.doi.org/10.2298/tsci191120185a.

Texte intégral

Résumé :

The phenomena of binary collisions and coalescence of droplets was investigated from experimental studies but still are missing from real applications such as from fuel injector. The main purpose of the current study is to investigate the phenomena of binary collisions and coalescence of droplets from a practical port fuel injector (PFI). To accomplish this, direct microscopic images are taken from high-speed video camera coupled with a long-distance microscope and Barlow lens using the backlighting method. Experimental optimization of the spatial resolution and the depth -of -field of the long-distance microscope and Barlow lens are achieved. Experimental results from the direct microscopic images are compared with predictions from empirical equations for different collision regimes. Droplet sizes and velocities of experimental coalescence droplets from collisions are compared with the values predicted by the equations. The main results of this study are: The probability of collision and coalescence is very low in a PFI. The tangential velocity components of small droplets play an essential role in shape deformation during collisions and coalescence of the droplets. The previous published empirical equations to calculate dimensionless parameters, the Weber number (We), the droplet diameter ratio (?), and impact parameter (B) are applicable to the coalescence of droplets in a PFI.

Styles APA, Harvard, Vancouver, ISO, etc.

41

Song, Lifei, Houjing Chen, Wenhao Xiong, Zaopeng Dong, Puxiu Mao, Zuquan Xiang et Kai Hu. « Method of Emergency Collision Avoidance for Unmanned Surface Vehicle (USV) Based on Motion Ability Database ». Polish Maritime Research 26, n^o 2 (1 juin 2019) : 55–67. http://dx.doi.org/10.2478/pomr-2019-0025.

Texte intégral

Résumé :

Abstract The unmanned surface vehicles (USV) are required to perform a dynamic obstacle avoidance during fulfilling a task. This is essential for USV safety in case of an emergency and such action has been proved to be difficult. However, little research has been done in this area. This study proposes an emergency collision avoidance algorithm for unmanned surface vehicles (USVs) based on a motion ability database. The algorithm is aimed to address the inconsistency of the existing algorithm. It is proposed to avoid collision in emergency situations by sharp turning and treating the collision avoidance process as a part of the turning movement of USV. In addition, the rolling safety and effect of speed reduction during the collision avoidance process are considered. First, a USV motion ability database is established by numerical simulation. The database includes maximum rolling angle, velocity vector, position scalar, and steering time data during the turning process. In emergency collision avoidance planning, the expected steering angle is obtained based on the International Regulations for Preventing Collisions at Sea (COLREGs), and the solution space, with initial velocity and rudder angle taken as independent variables, is determined by combining the steering time and rolling angle data. On the basis of this solution space, the objective function is solved by the particle swarm optimization (PSO) algorithm, and the optimal initial velocity and rudder angle are obtained. The position data corresponding to this solution is the emergency collision avoidance trajectory. Then, the collision avoidance parameters were calculated based on the afore mentioned model of motion. With the use of MATLAB and Unity software, a semi-physical simulation platform was established to perform the avoidance simulation experiment under emergency situation. Results show the validity of the algorithm. Hence results of this research can be useful for performing intelligent collision avoidance operations of USV and other autonomous ships

Styles APA, Harvard, Vancouver, ISO, etc.

42

Wu, Hequan, Libo Cao et Hongfeng Mao. « Crashworthiness Optimization of Thin-Walled Rail with Different Collision Boundary Conditions ». Open Mechanical Engineering Journal 9, n^o 1 (10 septembre 2015) : 558–63. http://dx.doi.org/10.2174/1874155x01509010558.

Texte intégral

Résumé :

As the world automotive crash safety regulations are different, it’s very important to design the energy absorbing structures that satisfy different collision boundary conditions. A large number of vehicle energy absorption beams dimensions were measured and then a common thin-walled rail was chosen. Considering the complexity of automobile collision boundary, finite element analysis and experimental design, interval uncertain algorithms, Kriging approximate model, NSGA - II genetic algorithm were combined to optimize the structure of the thin-walled rail with different impact velocity and different impact angle. Then the Pareto optimal solution was obtained. Thin walled beam after optimization has good energy absorption characteristics under different collision boundary conditions. Research results provide a method for the designing of a car that meets various crash regulations at the same time.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Ramirez-Argaez, Marco A., Diego Abreú-López, Jesús Gracia-Fadrique et Abhishek Dutta. « Numerical Study of Electrostatic Desalting Process Based on Droplet Collision Time ». Processes 9, n^o 7 (15 juillet 2021) : 1226. http://dx.doi.org/10.3390/pr9071226.

Texte intégral

Résumé :

The desalting process of an electrostatic desalting unit was studied using the collision time of two droplets in a water-in-oil (W/O) emulsion based on force balance. Initially, the model was solved numerically to perform a process analysis and to indicate the effect of the main process parameters, such as electric field strength, water content, temperature (through oil viscosity) and droplet size on the collision time or frequency of collision between a pair of droplets. In decreasing order of importance on the reduction of collision time and consequently on the efficiency of desalting separation, the following variables can be classified such as moisture content, electrostatic field strength, oil viscosity and droplet size. After this analysis, a computational fluid dynamics (CFD) model of a biphasic water–oil flow was developed in steady state using a Eulerian multiphase framework, in which collision frequency and probability of coalescence of droplets were assumed. This study provides some insights into the heterogeneity of a desalination plant which highlights aspects of design performance. This study further emphasizes the importance of two variables as moisture content and intensity of electrostatic field for dehydrated desalination by comparing the simulation with the electrostatic field against the same simulation without its presence. The overall objective of this study is therefore to show the necessity of including complex phenomena such as the frequency of collisions and coalescence in a CFD model for better understanding and optimization of the desalting process from both process safety and improvement.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Hatamikia, Sepideh, Ander Biguri, Gernot Kronreif, Michael Figl, Tom Russ, Joachim Kettenbach, Martin Buschmann et Wolfgang Birkfellner. « Toward on-the-fly trajectory optimization for C-arm CBCT under strong kinematic constraints ». PLOS ONE 16, n^o 2 (9 février 2021) : e0245508. http://dx.doi.org/10.1371/journal.pone.0245508.

Texte intégral

Résumé :

Cone beam computed tomography (CBCT) has become a vital tool in interventional radiology. Usually, a circular source-detector trajectory is used to acquire a three-dimensional (3D) image. Kinematic constraints due to the patient size or additional medical equipment often cause collisions with the imager while performing a full circular rotation. In a previous study, we developed a framework to design collision-free, patient-specific trajectories for the cases in which circular CBCT is not feasible. Our proposed trajectories included enough information to appropriately reconstruct a particular volume of interest (VOI), but the constraints had to be defined before the intervention. As most collisions are unpredictable, performing an on-the-fly trajectory optimization is desirable. In this study, we propose a search strategy that explores a set of trajectories that cover the whole collision-free area and subsequently performs a search locally in the areas with the highest image quality. Selecting the best trajectories is performed using simulations on a prior diagnostic CT volume which serves as a digital phantom for simulations. In our simulations, the Feature SIMilarity Index (FSIM) is used as the objective function to evaluate the imaging quality provided by different trajectories. We investigated the performance of our methods using three different anatomical targets inside the Alderson-Rando phantom. We used FSIM and Universal Quality Image (UQI) to evaluate the final reconstruction results. Our experiments showed that our proposed trajectories could achieve a comparable image quality in the VOI compared to the standard C-arm circular CBCT. We achieved a relative deviation less than 10% for both FSIM and UQI metrics between the reconstructed images from the optimized trajectories and the standard C-arm CBCT for all three targets. The whole trajectory optimization took approximately three to four minutes.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Rigo, Philippe, Abbas Bayatfar, Loïc Buldgen, Timothée Pire, Sara Echeverry et Jean-David Caprace. « Optimisation of Ship and Offshore Structures and Effective Waterway Infrastructures to Support the Global Economic Growth of a Country/Region ». Ciencia y tecnología de buques 11, n^o 21 (15 septembre 2017) : 9. http://dx.doi.org/10.25043/19098642.155.

Texte intégral

Résumé :

This paper includes the following parts:• Ship Structure Optimization: methodology to perform ship scantling optimization, decreasing steel weight and keeping the production cost at an acceptable level. We first review the links between “Design” and “Optimization” and secondly define the place of “Ship Structure Optimization” within the general framework of a “Ship Optimization”.• Ship impacts (Collision), with applications to navigation lock and dry dock gates: these gates have to be designed taking into account accidental loads, such as ship collisions. A new simplified analytical method is proposed, based on the so-called super-element method. This method was developed to rapidly assess the crashworthiness of the collided structure and avoid high computational effort of numerical simulations.• Inland waterway Navigation and the development in South America of Inland Waterway Classifications.• EMSHIP, European ERASMUS MUNDUS education program (www.emship.eu): the unique master’s degree in Ship & Offshore Structures awarded by the prestigious European Erasmus Mundus Program. EMSHIP shares the outstanding experiences of educators, trainers, industrial partners and students in the rapidly developing areas of marine and offshore engineering industry.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Huang, Xiao Bo, Ya Yu Huang et Dian Feng Sun. « The Optimization of Process Parameters of Large-Scale SAG Mill ». Applied Mechanics and Materials 401-403 (septembre 2013) : 316–19. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.316.

Texte intégral

Résumé :

This paper is based on the kinetic theory of ore and steel balls in the SAG Mill and theoretical research of power consumption. Orthogonal method is taken to design experimental plan while effective power of the SAG Mill, collision times between steel balls and the SAG Mill and collision times between steel balls and ore are designed as optimal objectives. Model with 9 experimental points is simulated by EDEM and experimental data are disposed Range Method in order to get the optimal combination of operating parameters of the SAG Mill.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Gai, Wendong, Ning Zhang, Jing Zhang et Yuxia Li. « A constant guidance law-based collision avoidance for unmanned aerial vehicles ». Proceedings of the Institution of Mechanical Engineers, Part G : Journal of Aerospace Engineering 233, n^o 4 (9 janvier 2018) : 1204–16. http://dx.doi.org/10.1177/0954410017751325.

Texte intégral

Résumé :

A method of automatic collision avoidance based on constant guidance law is proposed to solve the problem that the collision avoidance time is difficult to be estimated accurately during the collision avoidance process. The guidance command of the collision avoidance method is constant, and the lower bound of the constant guidance command satisfying the safe collision avoidance requirement is given by geometric method. Then, a collision avoidance time estimation method based on particle swarm optimization is proposed. In addition, the attitude control loop adopts the nonlinear proportional-integral-derivative based on tracking-differentiator, and the sufficient conditions for the system stability are given using the T-passive method. The simulation results show that the collision avoidance time estimation error is small and the maneuvering range of collision avoidance is smaller than the collision avoidance method based on proportional guidance and nonlinear dynamic inverse guidance. This method can achieve collision avoidance under the influence of wind disturbance and safety distance abrupt change.

Styles APA, Harvard, Vancouver, ISO, etc.

48

SHEN, Jie. « Automatic Optimization Method for Vehicle-pedestrian Collision Accident Reconstruction ». Journal of Mechanical Engineering 45, n^o 10 (2009) : 266. http://dx.doi.org/10.3901/jme.2009.10.266.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

49

Ahmed, Gamil, Tarek Sheltami, Ashraf Mahmoud et Ansar Yasar. « IoD swarms collision avoidance via improved particle swarm optimization ». Transportation Research Part A : Policy and Practice 142 (décembre 2020) : 260–78. http://dx.doi.org/10.1016/j.tra.2020.09.005.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

50

Xin, Xin, Abhishek Nagar, Gaurav Srivastava, Zhu Li, Felix Fernandes et Aggelos K. Katsaggelos. « Large Visual Repository Search with Hash Collision Design Optimization ». IEEE MultiMedia 20, n^o 2 (avril 2013) : 62–71. http://dx.doi.org/10.1109/mmul.2013.22.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Collision optimization »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres