Delay-Compensating Multipurpose Control of the Two-Link Manipulator

Abstract

The paper is devoted to the problem of stabilizing a two-link robotic manipulator in a given position, taking into account a set of requirements for the quality of the controlled motion dynamics in various modes. In particular, it is necessary to ensure astatism to the constant external disturbance. In the task considered, control is carried out directly by setting moments on the joints of the robot. The special property of the problem under consideration is that mathematical models of the dynamics of robotic manipulators have significant nonlinearities. An additional complexity is the presence of constant delay in control and external disturbance channels. To solve the problem without taking into account the delay, it is proposed to use a combination of the feedback linearization approach and the synthesis of a special multipurpose control structure. The procedure for synthesizing such regulators involves dividing an initially complex synthesis problem into simpler subtasks that can be solved relatively independently of each other. Moreover, depending on the current operating mode, individual parts of the multipurpose structure can be turned off to save computational resources of the on-board system. To compensate for the constant delay, a procedure for implementing a special transformation of the resulting multipurpose controller is described, which makes it possible to preserve the transfer matrix of the original closed-loop system. Thus, the original problem can first be solved without taking into account the delay, providing the desired dynamic characteristics, and then transform the resulting system taking into account the delay. To demonstrate the efficiency of the presented approach, the results of experiments with a computer model of a two-link robot manipulator in various operating modes are presented.