Quadruped robots consume a lot of energy, which is one of the factors restricting their application. Energy efficiency is one of the key evaluating indicators for walking robots. The relationship between energy and el...Quadruped robots consume a lot of energy, which is one of the factors restricting their application. Energy efficiency is one of the key evaluating indicators for walking robots. The relationship between energy and elastic elements of walking robots have been studied, but different walking gait patterns and contact status have important influences on locomotion energy efficiency, and the energy efficiency considering the foot-end trajectory has not been reported. Therefore, the energy consumption and energy efficiency of quadruped robot with trot gait and combined cycloid foot trajectory are studied. The forward and inverse kinematics of quadruped robot is derived. The combined cycloid function is proposed to generate horizontal and vertical foot trajectory respectively, which can ensure the acceleration curve of the foot-end smoother and more successive, and reduce the contact force between feet and environment. Because of the variable topology mechanism characteristic of quadruped robot, the leg state is divided into three different phases which are swing phase, transition phase and stance phase during one trot gait cycle. The non-continuous variable constraint between feet and environment of quadruped robot is studied. The dynamic model of quadruped robot is derived considering the variable topology mechanism characteristic, the periodic contact and elastic elements of the robot. The total energy consumption of walking robot during one gait cycle is analyzed based on the dynamic model. The specific resistance is used to evaluate energy efficiency of quadruped robot. The calculation results show the relationships between specific resistance and gait parameters, which can be used to determine the reasonable gait parameters.展开更多
针对传统的快速扩展随机树(rapidly-exploring random tree,RRT)算法收敛速度较慢、规划航迹曲折的缺点,提出基于启发式引导策略、动态步长策略、双层平滑度优化策略的综合改进RRT算法。利用概率对随机树的生长方向进行引导;采用动态步...针对传统的快速扩展随机树(rapidly-exploring random tree,RRT)算法收敛速度较慢、规划航迹曲折的缺点,提出基于启发式引导策略、动态步长策略、双层平滑度优化策略的综合改进RRT算法。利用概率对随机树的生长方向进行引导;采用动态步长进行未知空间的搜索;通过双层平滑度优化策略进行规划航迹的平滑,规划出适合四旋翼无人机飞行的可行航迹。与其它改进方法进行仿真比较,实验结果表明,综合改进RRT算法规划的航迹更短且平滑度更好,已将其应用于四旋翼无人机两种类型的突发障碍的航迹规划中。展开更多
基金supported by National Natural Science Foundation of China(Grant No.51375289)Shanghai Municipal National Natural Science Foundation of China(Grant No.13ZR1415500)Innovation Fund of Shanghai Education Commission of China(Grant No.13YZ020)
文摘Quadruped robots consume a lot of energy, which is one of the factors restricting their application. Energy efficiency is one of the key evaluating indicators for walking robots. The relationship between energy and elastic elements of walking robots have been studied, but different walking gait patterns and contact status have important influences on locomotion energy efficiency, and the energy efficiency considering the foot-end trajectory has not been reported. Therefore, the energy consumption and energy efficiency of quadruped robot with trot gait and combined cycloid foot trajectory are studied. The forward and inverse kinematics of quadruped robot is derived. The combined cycloid function is proposed to generate horizontal and vertical foot trajectory respectively, which can ensure the acceleration curve of the foot-end smoother and more successive, and reduce the contact force between feet and environment. Because of the variable topology mechanism characteristic of quadruped robot, the leg state is divided into three different phases which are swing phase, transition phase and stance phase during one trot gait cycle. The non-continuous variable constraint between feet and environment of quadruped robot is studied. The dynamic model of quadruped robot is derived considering the variable topology mechanism characteristic, the periodic contact and elastic elements of the robot. The total energy consumption of walking robot during one gait cycle is analyzed based on the dynamic model. The specific resistance is used to evaluate energy efficiency of quadruped robot. The calculation results show the relationships between specific resistance and gait parameters, which can be used to determine the reasonable gait parameters.
文摘针对传统的快速扩展随机树(rapidly-exploring random tree,RRT)算法收敛速度较慢、规划航迹曲折的缺点,提出基于启发式引导策略、动态步长策略、双层平滑度优化策略的综合改进RRT算法。利用概率对随机树的生长方向进行引导;采用动态步长进行未知空间的搜索;通过双层平滑度优化策略进行规划航迹的平滑,规划出适合四旋翼无人机飞行的可行航迹。与其它改进方法进行仿真比较,实验结果表明,综合改进RRT算法规划的航迹更短且平滑度更好,已将其应用于四旋翼无人机两种类型的突发障碍的航迹规划中。
