Heavy-load transfer robots are widely used in automobile production and machinery manufacturing to improve production efficiency.In order to meet the needs of large billet transfer,a 4-DOF transfer robot is designed i...Heavy-load transfer robots are widely used in automobile production and machinery manufacturing to improve production efficiency.In order to meet the needs of large billet transfer,a 4-DOF transfer robot is designed in this paper,which consists of parallel four-bar mechanisms.The Jacobian matrix referring to the mapping matrix from the joint velocity to the operating space velocity of the transfer robot can be solved by the differential-vector method.The mean value of the Jacobian matrix condition number in the workspace is used as the global performance index of the robot velocity and the optimization goal.The constraint condition is established based on the actual working condition.Then the linkage length optimization is carried out to decrease the length of the linkage and to increase the global performance index of velocity.The total length of robot rods is reduced by 6.12%.The global performance index of velocity is improved by 45.15%.Taking the optimized rod length as the mechanism parameter,the distribution of the motion space of the transfer robot is obtained.Finally,the results show that the proposed method for establishing the Jacobian matrix of the lower-mobility robot and for the optimization of the rods based on the velocity global performance index is accurate and effective.The workspace distribution of the robot meets the design requirements.展开更多
The transfer matrix of wrist force sensor is important for decoupling theoutput signals and enhancing the precision of wrist force sensor.This paper solves thetransfer matrix from the realization of optimal approximat...The transfer matrix of wrist force sensor is important for decoupling theoutput signals and enhancing the precision of wrist force sensor.This paper solves thetransfer matrix from the realization of optimal approximation of polynomial.First,thegeneral transfer matrix algorithm in the sense of L^2 and two kinds of modified algorithmare proposed.Then,starting from uniform approximation,the optimal transfer matrixalgorithm is offered and solved by the use of linear programming.The results of experi-ment and computation prove that these algorithms are effective.展开更多
Due to the increasing commercial interest in autonomy and sustainability,this paper reviews and presents a comprehensive summary of the resonant-inductive power transmission(RPT)technology for autonomous mobile robots...Due to the increasing commercial interest in autonomy and sustainability,this paper reviews and presents a comprehensive summary of the resonant-inductive power transmission(RPT)technology for autonomous mobile robots.It outlines historic and recent research activities in wireless power transmission,covering the fundamental operation of microwave,capacitive and inductive power transfer technologies,state-of-the-art developments in RPT for high-power applications,current design and health standards,technological drawbacks,and possible future trends.In this paper,coupling-enhanced pad designs,adaptive tuning techniques,compensation network designs,and control techniques are explored.Major design issues such as coupling variation,frequency splitting,and bifurcation are reviewed.The difference between maximum power transfer and maximum energy efficiency is highlighted.Human exposure guidelines are summarized from documentations provided by the Institute of Electrical and Electronics Engineers(IEEE)and the International Commission on Non-ionizing Radiation Protection(ICNIRP).Other standards like WPC’s Qi and Airfuel design standards are also summarized.Finally,the possible trends of the relevant research and development,particularly dynamic charging,are discussed.The intention of this review is to encourage designs that will relieve robot operators of the burden of frequent manual recharging,and to reduce downtime and increase the productivity of autonomous mobile robots in industrial environments.展开更多
深度强化学习(DRL)已被成功应用于移动机器人路径规划中,基于DRL的移动机器人路径规划算法适用于高维环境,是实现移动机器人自主学习的重要方法。而训练DRL模型需要大量的环境交互经验,这意味着更高的计算成本。此外,DRL算法的经验池容...深度强化学习(DRL)已被成功应用于移动机器人路径规划中,基于DRL的移动机器人路径规划算法适用于高维环境,是实现移动机器人自主学习的重要方法。而训练DRL模型需要大量的环境交互经验,这意味着更高的计算成本。此外,DRL算法的经验池容量有限,无法确保经验的有效利用。作为类脑计算重要工具之一的脉冲神经网络(Spiking Neural Networks,SNNs)以其独有的生物似真性,能同时融入时空信息,适用于机器人环境感知及控制。结合SNNs、卷积神经网络(CNNs)和策略融合,针对基于DRL的移动机器人路径规划算法进行研究,完成了以下工作:1)提出SCDDPG(SCDDP)算法。该算法利用CNNs对输入状态进行多通道特征提取,利用SNNs对提取的特征进行时空学习。2)在SCDDPG的基础上,提出SC2DDPG(SC2DDPG)算法。SC2DDPG通过设计状态约束策略对机器人运行状态进行约束,避免了不必要的环境探索,提升了SC2DDPG中DRL的收敛速度。3)在SCDDPG的基础上,提出了PFTDDPG(Policy Fusion and Transfer SCDDPG,PFTDDPG)算法。该算法采用分阶控制模式与DRL算法融合,针对环境中的楔形障碍物实施沿墙行走策略,并引入迁移学习对先验知识进行策略迁移。PFTDDPG算法不仅完成了单纯依靠RL不能完成的路径规划任务,还可以得到最优无碰路径。此外PFTDDPG提升了模型的收敛速度和路径规划性能。实验结果证明了所提出的3种路径规划算法的有效性,对比实验结果表明:在SpikeDDPG,SCDDPG,SC2DDPG和PFTDDPG算法中,PFTDDPG算法在路径规划成功率、训练收敛速度、规划路径长度等性能指标上表现最佳。本工作为移动机器人路径规划提出了新思路,丰富了DRL在移动机器人路径规划中的解决方案。展开更多
The previous research regarding the gait planning of quadruped robot focuses on the sequence for lifting o and placing the feet, but neglects the influence of body height. However, body height a ects gait performance ...The previous research regarding the gait planning of quadruped robot focuses on the sequence for lifting o and placing the feet, but neglects the influence of body height. However, body height a ects gait performance significantly, such as in terms of the stride length and stability margin. We herein study the performance of a quadruped robot using the equivalent mechanism concept based on metamorphosis. Assuming the constraints between standing feet and the ground with hinges, the ground, standing legs and robot body are considered as a parallel mechanism, and each swing leg is regarded as a typical serial manipulator. The equivalent mechanism varies while the robot moves on the ground. One gait cycle is divided into several periods, including step forward stages and switching stages. There exists a specific equivalent mechanism corresponding to each gait period. The robot's locomotion can be regarded as the motion of these series of equivalent mechanisms. The kinematics model and simplified model of the equivalent mechanism is established. A new definition of the multilegged robot stability margin, based on friction coe cient, is presented to evaluate the robot stability. The stable workspaces of the equivalent mechanism in the step forward stage of trotting gait under di erent friction coe cients are analyzed. The stride length of the robots is presented by analyzing the relationship between the stable workspaces of the equivalent mechanisms of two adjacent step forward stages in one gait cycle. The simulation results show that the stride length is larger with increasing friction coe cient. We herein propose a new method based on metamorphosis, and an equivalent mechanism to analyze the stability margin and stable workspace of the multilegged robot.展开更多
基金supported by the National Key R&D Program of China(No.2018YFB1307900)the Natural Science Foundation of Shanxi Province(Nos.201901D211009,201901D211010)the Technology In⁃novation Foundation of Shanxi University(No.2019L 0177).
文摘Heavy-load transfer robots are widely used in automobile production and machinery manufacturing to improve production efficiency.In order to meet the needs of large billet transfer,a 4-DOF transfer robot is designed in this paper,which consists of parallel four-bar mechanisms.The Jacobian matrix referring to the mapping matrix from the joint velocity to the operating space velocity of the transfer robot can be solved by the differential-vector method.The mean value of the Jacobian matrix condition number in the workspace is used as the global performance index of the robot velocity and the optimization goal.The constraint condition is established based on the actual working condition.Then the linkage length optimization is carried out to decrease the length of the linkage and to increase the global performance index of velocity.The total length of robot rods is reduced by 6.12%.The global performance index of velocity is improved by 45.15%.Taking the optimized rod length as the mechanism parameter,the distribution of the motion space of the transfer robot is obtained.Finally,the results show that the proposed method for establishing the Jacobian matrix of the lower-mobility robot and for the optimization of the rods based on the velocity global performance index is accurate and effective.The workspace distribution of the robot meets the design requirements.
文摘The transfer matrix of wrist force sensor is important for decoupling theoutput signals and enhancing the precision of wrist force sensor.This paper solves thetransfer matrix from the realization of optimal approximation of polynomial.First,thegeneral transfer matrix algorithm in the sense of L^2 and two kinds of modified algorithmare proposed.Then,starting from uniform approximation,the optimal transfer matrixalgorithm is offered and solved by the use of linear programming.The results of experi-ment and computation prove that these algorithms are effective.
基金partially funded by the Natural Sciences and Engineering Research Council of Canada(NSERC)through the Discovery Grant Program(RGPIN2018-05471 and RGPIN-2017-05762).
文摘Due to the increasing commercial interest in autonomy and sustainability,this paper reviews and presents a comprehensive summary of the resonant-inductive power transmission(RPT)technology for autonomous mobile robots.It outlines historic and recent research activities in wireless power transmission,covering the fundamental operation of microwave,capacitive and inductive power transfer technologies,state-of-the-art developments in RPT for high-power applications,current design and health standards,technological drawbacks,and possible future trends.In this paper,coupling-enhanced pad designs,adaptive tuning techniques,compensation network designs,and control techniques are explored.Major design issues such as coupling variation,frequency splitting,and bifurcation are reviewed.The difference between maximum power transfer and maximum energy efficiency is highlighted.Human exposure guidelines are summarized from documentations provided by the Institute of Electrical and Electronics Engineers(IEEE)and the International Commission on Non-ionizing Radiation Protection(ICNIRP).Other standards like WPC’s Qi and Airfuel design standards are also summarized.Finally,the possible trends of the relevant research and development,particularly dynamic charging,are discussed.The intention of this review is to encourage designs that will relieve robot operators of the burden of frequent manual recharging,and to reduce downtime and increase the productivity of autonomous mobile robots in industrial environments.
文摘深度强化学习(DRL)已被成功应用于移动机器人路径规划中,基于DRL的移动机器人路径规划算法适用于高维环境,是实现移动机器人自主学习的重要方法。而训练DRL模型需要大量的环境交互经验,这意味着更高的计算成本。此外,DRL算法的经验池容量有限,无法确保经验的有效利用。作为类脑计算重要工具之一的脉冲神经网络(Spiking Neural Networks,SNNs)以其独有的生物似真性,能同时融入时空信息,适用于机器人环境感知及控制。结合SNNs、卷积神经网络(CNNs)和策略融合,针对基于DRL的移动机器人路径规划算法进行研究,完成了以下工作:1)提出SCDDPG(SCDDP)算法。该算法利用CNNs对输入状态进行多通道特征提取,利用SNNs对提取的特征进行时空学习。2)在SCDDPG的基础上,提出SC2DDPG(SC2DDPG)算法。SC2DDPG通过设计状态约束策略对机器人运行状态进行约束,避免了不必要的环境探索,提升了SC2DDPG中DRL的收敛速度。3)在SCDDPG的基础上,提出了PFTDDPG(Policy Fusion and Transfer SCDDPG,PFTDDPG)算法。该算法采用分阶控制模式与DRL算法融合,针对环境中的楔形障碍物实施沿墙行走策略,并引入迁移学习对先验知识进行策略迁移。PFTDDPG算法不仅完成了单纯依靠RL不能完成的路径规划任务,还可以得到最优无碰路径。此外PFTDDPG提升了模型的收敛速度和路径规划性能。实验结果证明了所提出的3种路径规划算法的有效性,对比实验结果表明:在SpikeDDPG,SCDDPG,SC2DDPG和PFTDDPG算法中,PFTDDPG算法在路径规划成功率、训练收敛速度、规划路径长度等性能指标上表现最佳。本工作为移动机器人路径规划提出了新思路,丰富了DRL在移动机器人路径规划中的解决方案。
基金Supported by National Natural Science Foundation of China(Grant Nos.51775011,91748201)
文摘The previous research regarding the gait planning of quadruped robot focuses on the sequence for lifting o and placing the feet, but neglects the influence of body height. However, body height a ects gait performance significantly, such as in terms of the stride length and stability margin. We herein study the performance of a quadruped robot using the equivalent mechanism concept based on metamorphosis. Assuming the constraints between standing feet and the ground with hinges, the ground, standing legs and robot body are considered as a parallel mechanism, and each swing leg is regarded as a typical serial manipulator. The equivalent mechanism varies while the robot moves on the ground. One gait cycle is divided into several periods, including step forward stages and switching stages. There exists a specific equivalent mechanism corresponding to each gait period. The robot's locomotion can be regarded as the motion of these series of equivalent mechanisms. The kinematics model and simplified model of the equivalent mechanism is established. A new definition of the multilegged robot stability margin, based on friction coe cient, is presented to evaluate the robot stability. The stable workspaces of the equivalent mechanism in the step forward stage of trotting gait under di erent friction coe cients are analyzed. The stride length of the robots is presented by analyzing the relationship between the stable workspaces of the equivalent mechanisms of two adjacent step forward stages in one gait cycle. The simulation results show that the stride length is larger with increasing friction coe cient. We herein propose a new method based on metamorphosis, and an equivalent mechanism to analyze the stability margin and stable workspace of the multilegged robot.
