Research on Joint Torque Optimization Method of Redundant Space Manipulators with Vibration Suppression

Abstract

The space manipulator can exert its advantages of high efficiency and low cost, which can assist or even replace astronauts to complete a variety of space operations. However, the research has less consideration on joint torque optimization method with considering the influence of flexible factors on the manipulator. A joint torque optimization method of redundant space flexible manipulator with vibration suppression is proposed in this paper. The bending deformation of flexible connecting rod is described by the assumed mode method and the dynamic model of space flexible manipulator system is derived by the Lagrange method. On the basis of decomposing the dynamic equation of the flexible redundant manipulator, the joint torque is optimized as well as restraining the terminal vibration through introducing the Lagrange multiplier. Finally, simulation result shows that the increase rate of joint torque is not very obvious based on the Particle Swarm Optimization algorithm compared with the experiment without vibration suppression. The forward torque of first joint increases 20.2% and that of second joint only increases 4.1% while the backward torque of both two joints decrease obviously. Meanwhile, the running trajectory has excellent effect on vibration suppression of end effector of flexible manipulators. The terminal deformation in two directions is reduced by 21.3% and 78.6%. The decline of vibration deformation of end effector is obviously larger than the rise of joint torque, which verifies the feasibility and effectiveness of the algorithm.