The Research Of Pre-Imapct Configuration Planning And Post-Impact Control For Space Manipulator Capturing Object

Space manipulator has become an important component of space shuttle, space station and other space probes. On orbit, capturing operation is an important application for space manipulator, and taken as the major content. This thesis presents pre-impact configuration planning, impact dynamic analysis and post-impact control of space manipulator capturing object. The major work of this paper are consisted of the following parts:Based on momentum conservation principle of space manipulator, This thesis presents the effect of impact on system's angular momentum, two unique pre-capture configurations:"Straight-Arm Capture"(SAC) and"Generalized Straight-Arm Capture"(GSAC) are proposed based on the single-arm system, investigates the impact-configuration planning of dual-arm or multi-arm system, then"GSAC"was extended to the dual-arm system. This configuration satisfies"GSAC"and can reduce the coupling angular momentum during capture operation, and the burden of post-impact control. This avoids the limitation of joint velocity when controlling the compound (manipulator and object) and guarantees the stability of system. The simulation results show the effectiveness of this method. The"SAC"and"GSAC"find an appropriate pre-capture configuration to reduce the effect of impulsive force on system's angular momentum rather than eliminating its effect after capturing. These configurations are also applicable for rendezvous, docking and other issues of space impact. One unique strategy for capturing object is proposed, it accomplishes the capturation and controls the attitude of base effectively.This dissertation studys post-impact control after space manipulator capturing object. When the dynamic parameters contain errors or changes caused by the payload, adaptive control and robust control can deal with this problem efficiently.Utilizing the concept of"Reaction Null Space"(RNS) to accomplish the trajectory tracking of space manipulator in task space. According to on-line parameter identification, integrates adaptive control with Reaction null space control, obtains"Adaptive- Reaction Null Space Control"; then improves the Distributed Momentum Control (DMC), its improved form maintains the original characteristics of DMC and guarantees the the convergent property of end-effector tracking error during space manipulator capturing object. Similarly, we also get "Adaptive-Improved Distributed Momentum Control"making use of on-line parameter identification, then takes these two control algorithms into the single-arm and dual-arm systems. The simulation results show that they can overcome the effect of parameters errors, guarantees the stability of base attitude. At the same time, the simulation result verifies the"GSAC"can control the effect of parameters errors.Adaptive control can overcome the effect of constant or slowly-varying uncertain on control algorithm. When the system is effected by outer disturbance, quickly-varying uncertaion and unmodeled dynamics, its performance is not very well, but robust control has obvious advantages. This part integrates the theory of robust control with the control of"RNC"and"IDMC", obtains two kind of robust control, and then takes them into the single-arm and dual-arm system. The simulation results show the effectiveness of this method, keep the stability of space manipulator system.