Abstract: A spatial multi-arm robot almost cannot perform effective manipulation constraint on the target due to the large drag force and motion from the multi-contact handles of target when it manipulates a large target on orbit. The unpredictable external drag may result in the damage to the arms or the failure of capture task. A contact compliance control strategy is proposed based on a combination control law of whole-body impedance control at the center of mass (CoM) level and the independent admittance control at every supporting arm level. The robot can effectively manage the external drag force by constructing the mechanical impedance at the CoM of multi-rigid body system of spatial robot and the admittance at every arm, respectively. A quadratic programming (QP) method is used to build a system controller for the contact compliance control, which can unify the robot's whole-body motion behavior. The effectiveness of the proposed method is verified by simulation and the dimensionality reduction experiment on air-bearing bed. Key

Key words: spatialrobot, largetargetcapture, compliancecontact, impedancecontrol, quadraticprogramming