This paper discusses control problem of free-floating dual-arm space robot system with unknown payload parameters to track desired trajectory in inertial space, when the attitude of base is controlled and its location is uncontrolled. Combining the relationship of the linear momentum conversation and the Lagrange approach, the full-controlled dynamic equation and the Jacobian relation of free-floating dual-arm space robot are analysed and established. Based on the above results, for the case of free-floating dual-arm space robot system with unknown payload parameters, a composite control scheme is designed on the base of a computed torque controller and a fuzzy compensator to track desired trajectories in inertial space, i.e., balancing the effect of system unknown payload parameters on computed torque controller with fuzzy adaptive compensator, in order to ensure the whole closed-loop control system asymptotic stability with the existence of unknown payload parameters. The mentioned control scheme can effectively overcome the effect of system unknown payload parameters and control both the base attitude and the end-effector of dual-arm space robot, so that they can track the desired trajectory in inertia space, with obvious advantages neither the mentioned control scheme needs to measure and feedback the position, velocity and acceleration of the floating base, nor the mentioned control scheme needs to requirements for the dynamic equations of the system inertial parameters in linear function. A two planar dual-arm space robot system is simulated to verify the effectiveness of the proposed control scheme.
