Study On The Space Robot Motion Control

Space Robot will play an important role in future space projects. It is a development trend of human's future space activities that space exploration, such as constructing space station, repairing and recalling satellites, will be accomplished by space robots in place of astronauts. It is very necessary and significant to research space robot. In this paper, because of the different features of space robots compared with those fixed on earth, the main content of research work focused on kinematics modeling, dynamics modeling, path planning of free-floating space robot and adaptive control of space robot.Based on the intrinsic features of space robotic system caused by mobile base, the kinematics relationship between the end-effector and the joint variables is founded with Generalized Jacobian. Then we discuss the relationship between new matrix and the conventional Jacobian. From the kinematics we get Kinetic energy of the system. Substitute it into the Lagrange function, and then we get dynamic equation of the system.The problems of path planning for free-floating space robot are researched. Dynamic singularities are path dependent. With the conventional method of resolving the joint angle from the position and attitude of the end-effector, we need to resolve the inverse Jacobian, but all algorithms that use a Jacobian inverse fail at dynamic singularities. Ones that use a pseudo inverse Jacobian may result in large errors. The parameterization of the manipulator joint functions are introduced in this paper, this method makes use of the direct kinematical equations, so problems due to the dynamic singularities are avoided.Space robots have to face uncertainty on the parameters describing the dynamic properties, and all that will make great difficulty to the system control. Adaptive control may provide a feasible solution to those problems so that improve the adaptability and security. With the dynamic model we introduce the method of linear parameterization in terms of dynamic parameters, which can separate the system physical parameter (such as quality, inertia and centroid position) from the system states, then denote the systematic uncertainty parameters with one parameter vector,...