NONLINEAR FEEDBACK COMPOSITE CONTROL OF SPACE ROBOT SYSTEM WITH BOUNDED TORQUE INPUTS AND UNCERTAIN PARAMETERS

摘要

This thesis discusses control problem of free-floating space robot system with bounded torque inputs anduncertain parameters is studied. The kinematics and dynamics of the system were analyzed by use of momentumconservation. Base on the results, a nonlinear feedback composite control based computed torque method for freefloatingspace robot system with bounded torque inputs is put forward by embedding saturation function. Theresulting controller consists of two loops. The inner loop is the full compensation for space robot nonlineardynamics and the outer loop is the composite nonlinear feedback for stabilization and performance enhancement.With the feedback linearization technique and the Lyapunov theory, the asymptotic stability of the closed system isproved. In addition to the guaranteed stability properties, the controller takes advantage of a varying dampingratio induced by the composite nonlinear feedback control. The varying damping ratio allows fast transientresponse without overshoot, so the controller is more suitable for practical applications. The simulation results showthe feasibility and efficiency of the control scheme.