Path planning problem is the core and hot research topic of multiple Automatic Guided Vehicles (multi-AGVs) system. Although there are many research results, they do not solve the path planning problem from the perspe...Path planning problem is the core and hot research topic of multiple Automatic Guided Vehicles (multi-AGVs) system. Although there are many research results, they do not solve the path planning problem from the perspective of reducing traffic congestion. A collision-free path planning method based on improved A* Algorithm for multi-AGVs logistics sorting system is proposed in this paper. In the method, the environment of warehouse operation for AGVs is described by using grid method. The estimated cost of A* algorithm is improved by adding the penalty value of the paths that AGVs share with each other to alleviate traffic congestion and collision resolution rules are made according to different types of collisions. Then the collision-free path planning is done by combing the improved A* algorithm and collision resolution rules. The sorting efficiency of the method is compared with that of original A* algorithm. Simulation results show that the new collision-free path planning method can improve the sorting efficiency of multi-AGVs system and relieve traffic congestion.展开更多
This paper presents a novel general method for computing optimal motions of an industrial robot manipulator （AdeptOne XL robot） in the presence of fixed and oscillating obstacles. The optimization model considers th...This paper presents a novel general method for computing optimal motions of an industrial robot manipulator （AdeptOne XL robot） in the presence of fixed and oscillating obstacles. The optimization model considers the nonlinear manipulator dynamics, actuator constraints, joint limits, and obstacle avoidance. The problem has 6 objective functions, 88 variables, and 21 constraints. Two evolutionary algorithms, namely, elitist non-dominated sorting genetic algorithm （NSGA-II） and multi-objective differential evolution （MODE）, have been used for the optimization. Two methods （normalized weighting objective functions and average fitness factor） are used to select the best solution tradeoffs. Two multi-objective performance measures, namely solution spread measure and ratio of non-dominated individuals, are used to evaluate the Pareto optimal fronts. Two multi-objective performance measures, namely, optimizer overhead and algorithm effort, are used to find the computational effort of the optimization algorithm. The trajectories are defined by B-spline functions. The results obtained from NSGA-II and MODE are compared and analyzed.展开更多
Visual quality is a significant issue in today’s modern world which needs to be evaluated. This assessment is based on the observer’s perception and sight of space and attempts to introduce the criteria of spatial d...Visual quality is a significant issue in today’s modern world which needs to be evaluated. This assessment is based on the observer’s perception and sight of space and attempts to introduce the criteria of spatial desirability in the landscape. Analysis of the relationships between visual quality and structural features of the landscape is an effective way of conducting cognitive research. For this purpose, the analysis of visual quality was considered by compiling measurement and evaluation criteria, based on the concept of user preferences, in the part of Tehran-Qom Freeway, near the northeastern side of Imam Khomeini International Airport (Iran). The main objective of this research is to present a strategic plan for preserving and restoring the ecological landscape, creating a sense of place in the region, emphasizing gradual changes in the landscape during the movement and considering its relation to landscape aesthetics. For this purpose, after the questionnaire was prepared, the classifying visual quality method (Q-Sort) was used. Finally, using the results obtained from landscape analysis, identifying the components which led to the lack of visibility of individuals, and by using the geographic information systems (GIS), the strategic design of the area was designed.展开更多
文摘Path planning problem is the core and hot research topic of multiple Automatic Guided Vehicles (multi-AGVs) system. Although there are many research results, they do not solve the path planning problem from the perspective of reducing traffic congestion. A collision-free path planning method based on improved A* Algorithm for multi-AGVs logistics sorting system is proposed in this paper. In the method, the environment of warehouse operation for AGVs is described by using grid method. The estimated cost of A* algorithm is improved by adding the penalty value of the paths that AGVs share with each other to alleviate traffic congestion and collision resolution rules are made according to different types of collisions. Then the collision-free path planning is done by combing the improved A* algorithm and collision resolution rules. The sorting efficiency of the method is compared with that of original A* algorithm. Simulation results show that the new collision-free path planning method can improve the sorting efficiency of multi-AGVs system and relieve traffic congestion.
文摘This paper presents a novel general method for computing optimal motions of an industrial robot manipulator （AdeptOne XL robot） in the presence of fixed and oscillating obstacles. The optimization model considers the nonlinear manipulator dynamics, actuator constraints, joint limits, and obstacle avoidance. The problem has 6 objective functions, 88 variables, and 21 constraints. Two evolutionary algorithms, namely, elitist non-dominated sorting genetic algorithm （NSGA-II） and multi-objective differential evolution （MODE）, have been used for the optimization. Two methods （normalized weighting objective functions and average fitness factor） are used to select the best solution tradeoffs. Two multi-objective performance measures, namely solution spread measure and ratio of non-dominated individuals, are used to evaluate the Pareto optimal fronts. Two multi-objective performance measures, namely, optimizer overhead and algorithm effort, are used to find the computational effort of the optimization algorithm. The trajectories are defined by B-spline functions. The results obtained from NSGA-II and MODE are compared and analyzed.
文摘Visual quality is a significant issue in today’s modern world which needs to be evaluated. This assessment is based on the observer’s perception and sight of space and attempts to introduce the criteria of spatial desirability in the landscape. Analysis of the relationships between visual quality and structural features of the landscape is an effective way of conducting cognitive research. For this purpose, the analysis of visual quality was considered by compiling measurement and evaluation criteria, based on the concept of user preferences, in the part of Tehran-Qom Freeway, near the northeastern side of Imam Khomeini International Airport (Iran). The main objective of this research is to present a strategic plan for preserving and restoring the ecological landscape, creating a sense of place in the region, emphasizing gradual changes in the landscape during the movement and considering its relation to landscape aesthetics. For this purpose, after the questionnaire was prepared, the classifying visual quality method (Q-Sort) was used. Finally, using the results obtained from landscape analysis, identifying the components which led to the lack of visibility of individuals, and by using the geographic information systems (GIS), the strategic design of the area was designed.
