具有死区特性的空间机器人基于干扰观测器的L2反步控制

摘要

The trajectory tracking control problem of space robot system with uncontrolled base is discussed.Considering the existence of uncertain parameter and unknown dead-zone in the space robot,an L2 back-stepping control scheme based on the disturbance observer is proposed.Firstly,the dynamic model of system in inertia space is established by the combination of the second Lagrange method and Jacobi matrix.Then,the disturbance observer is used to observe and compensate the model error,and the observer error is eliminated by the method of L2 disturbance suppression.Meanwhile,a fuzzy compensator is used to compensate the bad effect caused by dead-zone.The control scheme doesn't need to know the accurate inertia parameters and linearly parameterize the dynamic model.Moreover,it is not necessary to estimate the upper bound of system uncertainties and the dead-zone parameters,which simplifies the system control.A planar space robot with two links is simulated to verify the feasibility of the control scheme.%研究了载体位置及姿态均不受控时空间机器人在惯性空间中的轨迹跟踪问题.考虑到系统存在参数不确定及死区特性等情况,提出了一种基于干扰观测器的L2反步控制方案.结合拉格朗日方程和系统Jacobi关系矩阵建立系统的动力学模型.利用干扰观测器对系统建模误差进行观测补偿,并通过L2干扰抑制法对观测误差进行消除,同时采用死区模糊补偿器对系统死区特性造成的影响进行补偿.该控制方案不需要预知准确的惯性参数,不用对惯性参数进行线性化处理,并且不要求估计系统不确定项和死区参数的上界,从而简化了系统的控制.数值仿真证明了该控制方案的有效性.