Abstract
The present paper proposes a distributed feedback control for redundant manipulators based on virtual arms. The virtual arm has the same kinematic structure as the manipulator except that its end-point is located on the joint or link of the manipulator. Therefore, the redundant manipulator can be represented as a set of virtual arms. First of all, each subsystem which constitutes the distributed control system is designed corresponding to the virtual arm. Dynamic behavior of each subsystem is basically an end-point position feedback control of virtual arm on the operation space. Then, it is shown that the position control of the manipulator utilizing kinematic redundancy can be realized through the cooperative and competitive interactions between subsystems, and that the dynamic behavior of the whole system is always stable. The advantages of the method are summarized as follows:
1) each subsystem can work fully autonomously and the joint control torque of the redundant manipulator can be calculated in a parallel and distributed way,
2) the kinematic redundancy of the manipulator can be utilized positively using virtual arms,
3) some subtasks can be executed by introducing a potential function on the joint space of the manipulator.
