Hierarchical Passivity-Based Force-Position-Configuration Coordinated Control of Multi-Branch Spacecraft

The multibranch spacecraft have attracted significant attention owing to their exceptional dexterity, extensive operational range, and capability to independently or collaboratively execute diverse space tasks. The control target of this kind of spacecraft mainly lies in two levels, i.e., precise force/position control of the arm end-effector with adaptivity to the environment and configuration maintenance control of the whole body with guaranteed stability. This article focuses on the whole-body coordination and compliance control of redundant multibranch spacecraft in the space station surface manipulation scenario, and proposes a hierarchical passivity-based force-position-configuration multilevel coordinated control framework. In the proposed framework, the leader–follower cooperative strategy is used to generate the desired positions and attitude of the end-effector; the hierarchical passive control structure based on the null space is utilized to enable multilevel compatible control; the adaptive variable impedance control strategy is embedded in the end-effector compliance control level to achieve safe and compliant contact on the target; the passive compensation control of the multiarm spacecraft system based on the energy tank is added in each control level to ensure the safety and stability of the system operation process. Finally, the efficacy of the proposed control framework is demonstrated through formal proofs and simulation results.