Optimal placement of a two-link manipulator for door opening

This paper presents a study on the optimal base location and arm motion of a mobile manipulator for door opening task. Numerical simulation results show that the base location where the manipulability of the two-link arm is almost degenerated at the start and end points of door opening is optimal.We show by analysis that the location has an advantage in supplying kinetic energy to the door by using torques at the joints of arm. In order to represent properly the arm motion near a singular point of manipulability, the rotational motion of the door is parameterized by piecewise fifth order polynomials of time, and the parameters of polynomials are optimized to minimize the joint torques.