Piecewise strategy and decoupling control method for high pose precision robotic peg-in-hole assembly

Existing compliance control methods take the force/moment precision as the only metric but do not explicitly guarantee the pose precision between assembly objects. In this paper, we first find significant time-variant and coupling characteristics in the process of modelling peg-in-hole assembly. Then, piecewise strategy and decoupling control (PSDC) method is proposed to explicitly improve the pose precision between the peg and hole. During designing PSDC controller, given the time-variant characteristic of assembly, piecewise strategy is utilized to improve the rapidity and stability of control, which is the basis of the pose precision. Given the coupling characteristic of assembly, an identification method of modelling error on the equation of output is proposed and the corresponding decoupling module is designed to avoid the system error on the pose between the peg and hole. Finally, the simulation and experiment results demonstrate that PSDC method achieves higher pose precision assembly in a force-guided compliance control framework.