Hybrid position, posture, force and moment control of robot manipulators

There are lots of contact works with objects in works performed by manipulators. Moreover, the need of the surface contact works of polish, grinding, application, paint, inspection, etc., performed by manipulators is increasing rapidly in recent years. However, reports of studies of this kind of work are rare. This paper proposed a hybrid position, posture, force, and moment control for a six-degree-of-freedom (6-DOF) robot manipulator for the surface contact work by expansion of the conventional hybrid position and force control. Moreover, to avoid calculation of the inverse Jacobian matrix, a difference inverse kinematics method of two types was proposed to return position errors and posture errors of constraint coordinates to angle errors of joint coordinates. Using the proposed difference inverse kinematics method, a hybrid control structure was built to provide control accuracy and practicality. Furthermore, a character-erasing experiment was performed using a whiteboard as an example of surface contact work using an RPY type 6-DOF manipulator. Results of this experiment verified the effectiveness of our hybrid control for use in surface contact work.