ELECTROHYDRAULIC SERVO MOTOR VERSUS ELECTRIC SERVO DC MOTOR IN THE PRESENCE OF MECHANICAL DISTURBANCES

The manipulation of the rotating mechanical loads in an industrial context relies on the choice of actuator type. Several studies report on the comparison of power, size, and other technical specifications. This paper presents a comparative study of the angular velocity control of a mechanical load driven by an electro-hydraulic servo motor and the same load driven by an electric DC servo motor under identical mechanical disturbances. First, both motors are mathematically modelled to highlight their nonlinear dynamics. Second, a velocity PID controller is developed using the classical Ziegler-Nichols approach for each motor. Finally, the nonlinear servosystems are implemented and run in Matlab / Simulink with a mechanical disturbance profile. It is shown that the electric servo motor proves more robust than its electro-hydraulic equivalent, particularly in the presence of mechanical disturbance.