一种新型拟人机械腿的运动传递性能分析

摘要

针对当前多数拟人机械腿采用串联机构出现的运动惯性大、承载能力小,不能很好地满足拟人机器人运动特性需要的问题,提出了一种新型拟人机械腿并联机构,介绍了其结构布局特点,该机构具有3个自由度,外观匀称,与人腿相仿度高,在结构上实现了人体踝关节和膝关节功能.建立了该并联机械腿的位置反解方程,基于该方程用矢量法推导出了线速度和角速度雅可比矩阵,分别定义两矩阵的条件数和可操作度作为其运动学性能指标,分析了各性能指标在工作空间内的分布规律.研究结果表明:拟人机械腿速度传递性能良好且稳定,脚掌的运动传递性能几乎不受屈膝角度的影响.仿真结果符合人体腿部的运动要求,为当前拟人机械腿的研究提供了一种新的构型.%Aiming at the problems of high moment inertia,low bearing capacity and can't meet the requirements of motion characteristics of humanoid robot of serial mechanism used in the current mechanical humanoid legs, a novel parallel mechanical humanoid leg was proposed, and the layout feature of a parallel humanoid mechanical leg was described. The inverse position equation of this mechanism was established. Based on this equation, the analytic expressions for the linear and angular velocity of the Jacobian matrix were derived by using the Vector method. Condition number and maneuverability of the two matrices were defined as the kinematics performance index to evaluate the kinematic transmission. At last,the distribution of the evaluation index was drawn out on the workspace respectively. The results indicate that kinematics performance of the foot is almost not affected by the movement of keen joint. The structure has three degrees of freedom and has the motion function of the ankle joint and keen joint. Simulation results meet the requirements of joint mechanics in human walking,which can provide a new configuration for the study of humanoid mechanical leg.