Development of the Method of Formation the Reference Signals for Electric Actuators of Manipulators with Redundant Degrees of Freedom. Part I

Abstract

The solution of task of maintaining the dynamic accuracy of control of working tools of multilink manipulators (MM) when they move along arbitrary spatial trajectories is presented in this paper. In this case, constructive restrictions in all degrees of freedom (DoF) of manipulators and special cases of location of their links are taken into account. These special (singular) positions are characterized by ambiguity in solving inverse kinematics problem of these MM. Maintaining of control accuracy is proposed to be ensured by excluding the enter of all DoFs of manipulators to the restrictions, as well as excluding the enter of their working tools to the boundaries of the working area. This is accomplished by using a redundant DoF when approaching these undesirable positions. In the first part of the article, the features of the new solution of the inverse kinematics problem are considered and singular positions for 6-DoF manipulators with PUMA kinematic schemes are described. The presented solution of the inverse kinematics problem takes into account various combinations of genera- lized coordinates of the MM, which ensure the movement of their working tools to the specified positions with the required spatial orientation. This solution has low computational complexity compared to other known methods. This allows the use of low-power microprocessor computers to control the MM. The results of the performed mathematical simulation confirmed the high efficiency of using the proposed approach to the contour control of the MM.