欠驱动柔性机器人的动力学建模与耦合特性

DYNAMIC MODELING AND COUPLING OF UNDERACTUATED FLEXIBLE ROBOT

运用有限元法,建立具有柔性杆的欠驱动机器人的动力学一般模型。以此模型为基础,分析系统的主动与被动关节的加速度耦合和被动关节与驱动力矩的动力学耦合效应,并针对欠驱动柔性机器人,提出柔性杆弹性变形分别与主动关节、被动关节动力学耦合的新指标。将欠驱动柔性机器人的被动关节加速度耦合和力矩耦合仿真结果与刚性系统相比较,在某个驱动器位置,柔性系统得到较大的耦合值,说明此时柔性系统更加有利于能量的传递,体现了杆件的弹性变形对系统动力学特性的影响。同时,数值仿真还表明这些动力学耦合指标对欠驱动机器人的结构设计、位形设计、驱动装置位置及系统控制都具有重要意义。

A dynamic model for underactuated robots with link flexibility is presented using finite element method. Based on this model, the dynamic coupling effects are analyzed, including the acceleration coupling between active joints and passive ones, the dynamic coupling between passive joints and driving torques. A new index is proposed to describe the dynamic coupling between the elastic deformations of flexible links and the active as well as the passive joints, respectively. Comparing the simulation results of acceleration and torque coupling of underactuated flexible system with those of the rigid system, it has been shown that the former system can obtain greater coupling values at the certain actuator configuration. The flexible system can supply a better energy transmission at this configuration. Therefore, the results indicate that the elastic deformations of flexible links have important influence on the dynamic characteristics of the system. The dynamic coupling effects are of significance in structure design, configuration design, actuator placement and control of underactuated robots system.