Active 4 DOF based RCC wrist using segmented IPMCs for robotic peg-in-hole assembly

During robotic peg-in-hole assembly, there always exist position and orientation errors between two mating parts. In order to compensate these errors, compliant mechanisms are required that can correct the errors before assembly. In this paper, a new active 4 degree of freedom (DOF) based Remote Centre Compliance (RCC) mechanism using two segmented IPMCs for micro assembly is proposed. Each IPMC strip is used as a 2 DOF link by cutting the top electrode layer of each IPMC at the centre using a CO2 laser. A peg-hole assembly task is modeled analytically where the misalignment of peg is corrected by IPMC tip force. The force applied on the peg by the RCC is controlled by giving a voltage (0–3V) to different IPMC segments through a proportional-derivative (PD) controller. Simulations and experiments were carried out by developing an active RCC wrist using IPMCs and various cases for peg-in-hole assembly are analyzed by using a vision feedback system. The results prove that the new active RCC based wrist using segmented IPMCs improves peg-in-hole assembly.