Adaptive Control of Free-floating Space Robot with Inertia Parameter Uncertainties

In order to cope with the inertia parameter uncertainty of a free-floating space robot system,an adaptive trajectory tracking control method is proposed in Cartesian space.Dynamic equations in the joint space of the free-floating space robot system are formulated using the extended manipulator model,and then the dynamic equations in Cartesian space of the free-floating space robot system are derived.During the design of the adaptive controller for the free-floating space robot based on inverse dynamics,a nominal controller with fixed parameters offline and a compensative controller online are proposed to ensure invertibility of the inertial matrix of the dynamics model and real-time estimation of the parameters.The closed-loop system is proved to be stable and convergent by Lyapunov methods.Finally,numerical simulations of a two-link planar free-floating space robot are given using the proposed control method,which demonstrate good trajectory tracking performance of the end-effector of the free-floating space robot in Cartesian space.