辅助起立机器人轨迹追踪仿真及试验研究

Simulation and experimental study on trajectory tracking of the assistive standing-up robot

目的为实现辅助起立机器人对不同期望轨迹规划和追踪,辅助患者完成起立训练,提出轨迹追踪与梯形速率相结合方法。方法分析辅助患者起立受力情况,推导患者在机器人辅助起立时力与力矩平衡方程,并根据期望轨迹插值点、末端执行器运动速率以及当前位置点,推导辅助起立机器人轨迹追踪算法,利用Simulink/Stateflow软件建立仿真平台。搭建Xpc目标机、主机、起立机器人和三维运动分析系统试验台,对直线和任意曲线以及患者起立轨迹和速率进行测试。找出影响追踪轨迹速率和精度的参数以及梯形速率与患者起立速率差异。结果实现了辅助起立机器人对不同轨迹精确位置追踪,起立运动轨迹和梯形速率均满足患者起立速率要求,可实现患者对不同运动轨迹和速率要求。结论轨迹追踪算法结合梯形速率可实现辅助起立机器人对直线、规则或不规则曲线较高精度追踪,辅助患者实时在线起立训练,考虑患者起立轨迹、速度和加速度差异而搭建的模拟和试验平台可更为有效地辅助起立。

Objective To establish a new trajectory tracking algorithm combined with trapezoidal velocity, so as to realize the trajectory control of the assistive standing-up robot and help subjects complete the standing-up train- ing. Methods Forces of the assistive standing-up robot acting on subjects were analyzed by deducing the force and moment balance equations. According to the interpolation points of the target curve, trapezoidal velocity and current position points of the end-effector, the trajectory tracking algorithm of the assistive standing-up robot was developed, and a simulation platform was built up by Simulink/Stateflow software. Based on the established Xpc target and host computer, assistive standing-up robot and 3D motion analysis system, trajectory tracking of the straight line, curves in different shapes, standing-up curve of the subjects were tested. Parameters that affected the velocity and accuracy of trajectory tracking as well as the differences in trapezoidal velocity and standing-up velocity were discovered. Results Accurate positon control of the assistive standing-up robot was achieved by trajectory tracking algorithm. The standing-up trajectory curve and trapezoidal velocity could meet the requirement of standing-up velocity for the subjects and fulfill their requirements for different curve shapes and velocities. Con- clusions The assistive standing-up robot using trajectory tracking algorithm combined with trapezoidal velocity can accurately track the target curves without limitation of curve shapes, and help the standing-up training for subjects. The established simulation and test platform in consideration of different subjects＇ standing-up trajectory curve, velocity and accelaraion will assist standing-up more effectively.