Collaborative Control of Space Flexible Multiarm Robot Exploiting Stress Stiffening Effect

Using space multiarm robots for operation is an advanced and challenging space technology. This article proposes a control strategy with compliance and variable stiffness for space multiarm robots. First, the system composition of the space multiarm robot is introduced. In particular, a quick locking and releasing device is proposed, which allows the robot to switch between open-chain and self-closed-chain configurations to specific task requirements. Then, the dynamic models of the space multiarm robot considering joint flexibility are established for two configurations. Furthermore, the stress stiffening effect is introduced, proving that the flexible robot's structural stiffness can be changed by adjusting the internal force in the self-closed-chain configuration. Next, a composite force control strategy for the space multiarm robot considering flexibility is designed based on singular perturbation theory to achieve variable stiffness and compliance control. Finally, the proposed collaborative control strategy is validated via simulations and experiments. The results show that the control strategy actively adjusts system stiffness while maintaining control compliance.