Research On Adaptive Control Algorithm Of Free-Floating Space Robot

With the development of people's space activities, more and more manufacture, machining, assemblage, maintenance, repairing in space will be developed in the future space activities. So burdensome works can not be finish by astronauts only, meanwhile, sending people to space is costly and risky. So must make the best of space robots. This mode can reduce the usage of expensive fuel, extend the life of the space robot, and save a lot of cost. In this paper, the kinematics and dynamics model, adaptive control, and simulation of free-floating space robot system is investigated.Firstly, according to the relations of free-floating space robot system movement and geometry, this paper analyzes the kinematics of free-floating space robot; derive the system's Jacobi matrix and also analyzes the dynamic singularity, PDW and PIW work space.Secondly, derives the dynamic equation of free-floating space robot system with the Lagrange equation. As the dynamics of free-floating space manipulator basing on the law of conservation of momentum have the characteristics of nonlinear parameters, some controls based on the linear parameters model can not be applied in this model. To overcome this problem, expand manipulator model is applied to derive the system dynamics. At last, Verifies the correctness of the dynamic model by comparing the curve gained from the Adams software with the curve gained from the Matlab software.Finally, the system uses adaptive control algorithm aiming at the uncertainty of the system parameters. We gain the linearly parameterized dynamic model of free-floating space robot basing on the extended robot method and the parameter linear separation method, and this model is fit for using the adaptive control method. This paper studies the off-line adaptive control and the on-line adaptive control methods. Aiming at the existing dynamic disturb of not modeling, this paper proposes the control method that integrates off-line and on line adaptive control. It consists of an off-line parameter identifier to identify structured system dynamics and on-line dynamic compensator to compensating for dynamic uncertainties, then online estimate integrates with computed-torque controller, controlling the end-effector tracking the desired trajectories well. Meanwhile, the paper proves the stability of the proposed control algorithms and does the simulation study, besides, comparing and analyzing the simulation results to illustrate the validity and effectiveness of the proposed control scheme.