遗传算法优化的线性二次型调节器控制下3-UPS并联机器人稳定性分析

Stability analysis of parallel robot under linear quadratic regulator control based on genetic algorithm optimization

通过对3-UPS并联机器人进行动力学建模与状态空间分析,基于遗传算法(GA)优化的线性二次型调节器(LQR)控制方法对其进行控制仿真,结合多体系统振动理论,并运用MATLAB软件和ADAMS软件联合仿真,分别对该并联机器人在动平台施加外部载荷、定平台施加随机振动,以及动、定平台施加复合干扰3种情况下机器人的末端稳定性进行分析。结果表明:GA优化的LQR控制下,机器人动平台质心振动的衰减时间和振动幅度都明显减小,且共振峰也明显降低,但是高频振动处的减振效果不明显;机器人动平台质心x和y方向的共振频率均保持在5 Hz左右,而z方向的共振频率却有明显的后移现象,逐渐向高频(10 Hz)靠近。该研究为分析并联机器人稳定性与工作精度提供了一定的理论基础。

Through dynamic modeling and state space analysis of 3-UPS parallel robot,the Linear-Quadratic-Regulator(LQR)control method based on Genetic Algorithm(GA)optimization was used to make control simulation for 3-UPS parallel robot.Combining with the multi-body system vibration theory,the terminal stability of the robot was analyzed under three conditions with MATLAB software and ADAMS software for co-simulation.The conditions were the external load was applied to the moving platform,the random vibration was applied to the fixed platform and the compound interference was applied to the fixed platform.The results showed that under GA-optimized LQR control,the decay time and vibration amplitude of the vibration of robot moving platform were significantly reduced,and the resonance peak was also significantly reduced,but the vibration reduction effect at high-frequency vibration was not obvious.The resonance frequency in centroid x and y direction of robot moving platform were kept at about 5 Hz,while the resonance frequency in z direction had a significant backward shift phenomenon,gradually approaching the high frequency(10 Hz).This research provided a theoretical basis for analyzing the stability and working accuracy of parallel robots.