Two-arm cooperative assembly using force-guided control with adaptive accommodation

Abstract

A two-arm cooperative assembly (or insertion) algorithm is proposed. As a force-guided control method for the cooperative assembly, the adaptive accommodation controller is adopted since it does not need any complicated contact state analysis nor depends on the geometrical complexity of the assembly parts. Also, the RMRC (resolved motion rate control) method using a relative Jacobian is used to solve inverse kinematics for two manipulators. By using the relative Jacobian, the two cooperative redundant manipulators can be structured as a new single redundant manipulator. The two arms can perform a variety of insertion task by a relative motion between their end effectors. A force/torque sensing model, using an approximated penetration depth calculation algorithm is developed and used to compute a contact force/torque in the graphic assembly simulation. By using the adaptive accommodation controller and the force/torque sensing model, a spatial cooperative assembly tasks have been successfully executed in the graphic simulation. Finally, through a cooperative assembly task experiment using a humanoid robot, CENTAUR, which inserts a spatially bent pin into a hole, its feasibility and applicability are verified.