Design and Implementation of a Digital Controller for a Servo-Hydraulic Testing Machine

Servo-hydraulic testing machines are used to characterize materials and evaluate mechanical assemblies. The correct operation of this type of equipment makes it necessary to use an electronic controller, normally provided by the same manufacturer of the machine. This paper presents the design and implementation of a digital rod displacement controller for a non-commercial servo-hydraulic testing machine. The offline identification process of the system plant is described, for which a linear model is used to represent its dynamics. The designed control strategy is based on a Proportional-Integral-Derivative (PID) controller and a digital filter that improves the tracking of the reference signal. Simulation and experimental results are presented from which the implemented design is verified.