Independent-joint Control of 5DOF Robotic Manipulators by Fractional-Order PI^ν Controllers

Abstract

This paper describes a design procedure of fractional-order controllers for independent-joint control of a 5DOF robotic manipulator. The control scheme of each joint includes a double loop involving fractional-order PI <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ν</sup> controllers for both position and speed control with feed-forward action. The design approach is general and consists in closed-form tuning formulas, which directly give the controllers parameters depending on specifications defined in the frequency domain. Preliminary tests are performed on a detailed simulation model of the manipulator to evaluate the effectiveness of the proposed control scheme. Better performance with respect to standard PID controllers is obtained, even in presence of disturbances and plant nonlinearities.