Servo Controller Compensation Methods Selection of the Correct Technique for Test Applications

Servo-hydraulic test systems are used to apply precise loads and displacements to specimens as part of a program of evaluation in the laboratory. For the test system to correctly load the specimen the type of servohydraulic control must be carefully selected. Factors such as accuracy, repeatability, control range and stability depend on the matching of the control scheme to the characteristics of the test stand, specimen and the command profile. This paper reviews the compensation methods available with particular reference to practical applications of the different methods in the laboratory testing of automobiles from components of all types through sub-systems to full vehicles.