Timed weighted marked graphs are a subclass of timed Petri nets that have wide applications in the control and performance analysis of flexible manufacturing systems.Due to the existence of multiplicities(i.e.,weights...Timed weighted marked graphs are a subclass of timed Petri nets that have wide applications in the control and performance analysis of flexible manufacturing systems.Due to the existence of multiplicities(i.e.,weights)on edges,the performance analysis and resource optimization of such graphs represent a challenging problem.In this paper,we develop an approach to transform a timed weighted marked graph whose initial marking is not given,into an equivalent parametric timed marked graph where the edges have unitary weights.In order to explore an optimal resource allocation policy for a system,an analytical method is developed for the resource optimization of timed weighted marked graphs by studying an equivalent net.Finally,we apply the proposed method to a flexible manufacturing system and compare the results with a previous heuristic approach.Simulation analysis shows that the developed approach is superior to the heuristic approach.展开更多
Although the torso plays an important role in the movement coordination and versatile locomotion of mammals,the structural design and neuromechanical control of a bionic torso have not been fully addressed.In this pap...Although the torso plays an important role in the movement coordination and versatile locomotion of mammals,the structural design and neuromechanical control of a bionic torso have not been fully addressed.In this paper,a parallel mechanism is designed as a bionic torso to improve the agility,coordination,and diversity of robot locomotion.The mechanism consists of 6-degree of freedom actuated parallel joints and can perfectly simulate the bending and stretching of an animal’s torso during walking and running.The overall spatial motion performance of the parallel mechanism is improved by optimizing the structural parameters.Based on this structure,the rhythmic motion of the parallel mechanism is obtained by supporting state analysis.The neural control of the parallel mechanism is realized by constructing a neuromechanical network,which merges the rhythmic signals of the legs and generates the locomotion of the bionic parallel mechanism for different motion patterns.Experimental results show that the complete integrated system can be controlled in real time to achieve proper limb-torso coordination.This coordination enables several different motions with effectiveness and good performance.展开更多
基金supported by the National Natural Science Foundation of China(61803246,61703321)the China Postdoctoral Science Foundation(2019M663608)+2 种基金Shaanxi Provincial Natural Science Foundation(2019JQ-022,2020JQ-733)the Fundamental Research Funds for the Central Universities(JB190407)the Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing,Xi’an University of Technology(SKL2020CP03)。
文摘Timed weighted marked graphs are a subclass of timed Petri nets that have wide applications in the control and performance analysis of flexible manufacturing systems.Due to the existence of multiplicities(i.e.,weights)on edges,the performance analysis and resource optimization of such graphs represent a challenging problem.In this paper,we develop an approach to transform a timed weighted marked graph whose initial marking is not given,into an equivalent parametric timed marked graph where the edges have unitary weights.In order to explore an optimal resource allocation policy for a system,an analytical method is developed for the resource optimization of timed weighted marked graphs by studying an equivalent net.Finally,we apply the proposed method to a flexible manufacturing system and compare the results with a previous heuristic approach.Simulation analysis shows that the developed approach is superior to the heuristic approach.
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.51605039)in part by the Shaanxi International Science and Technology Cooperation Project(Grant No.2020KW-064)+3 种基金in part by the Open Foundation of the State Key Laboratory of Fluid Power Transmission and Control(Grant No.GZKF-201923)in part by the China Postdoctoral Science Foundation(Grant No.2018T111005)in part by the Fundamental Research Funds for the Central Universities(Grant Nos.300102259308 and 300102259401)in part by the China Scholarship Council.
文摘Although the torso plays an important role in the movement coordination and versatile locomotion of mammals,the structural design and neuromechanical control of a bionic torso have not been fully addressed.In this paper,a parallel mechanism is designed as a bionic torso to improve the agility,coordination,and diversity of robot locomotion.The mechanism consists of 6-degree of freedom actuated parallel joints and can perfectly simulate the bending and stretching of an animal’s torso during walking and running.The overall spatial motion performance of the parallel mechanism is improved by optimizing the structural parameters.Based on this structure,the rhythmic motion of the parallel mechanism is obtained by supporting state analysis.The neural control of the parallel mechanism is realized by constructing a neuromechanical network,which merges the rhythmic signals of the legs and generates the locomotion of the bionic parallel mechanism for different motion patterns.Experimental results show that the complete integrated system can be controlled in real time to achieve proper limb-torso coordination.This coordination enables several different motions with effectiveness and good performance.
