柔性关节空间机械臂建模、控制与仿真

Modeling,Control and Simulation of Space Manipulators with Flexible Joints

关节是空间机械臂的核心部件,在机械臂动力学中起着重要的作用。精确的关节动力学模型,是机械臂系统设计、分析和控制的基础。以某空间机械臂原理样机为研究对象,建立了考虑关节柔性和摩擦特性的动力学模型。分别利用扭转刚度测试平台和驱动组件性能测试仪,测得了关节的刚度系数和摩擦系数。并进行了考虑关节力矩饱和非线性的PD控制律设计,同时给出了稳定性证明。为消除动力学方程系数矩阵的时变性和刚度矩阵的奇异性,将动力学方程进行等价变换,从而利用精细积分方法进行数值仿真。仿真结果表明,抗饱和非线性PD控制律能够保证机械臂在负载变化范围内,满足位置控制的精度要求。

Joints play a very important role in dynamic behavior of space manipulators as one of the critical components.A precise model of the joint is the basis of design,analysis and control of manipulators.The dynamic model of the manipulator with flexible joints was presented on a concrete example which is the prototype of a space manipulator.The torsional stiffness of the joint was measured in the torsional stiffness testing platform,and the coefficients of the friction model were estimated from the test results of the performance testing instrument for the drive unit.And the anti-windup nonlinear PD control was designed to avoid the torque saturation of the joints,and the stability of the control law was proved.In order to avoid the time-varying of the coefficient matrices and the singularity of the stiffness matrices,the dynamic equations were equipollently transformed,so that the Precise Integration Algorithm can be used in numerical simulation.The simulation results illustrate the proposed control scheme can achieve precise position control with a range of desired payload.