Nonlinear control and sensitivity analysis of a spatial multi-axis servo-hydraulic test facility

This paper presents a nonlinear control concept of a spatial multi-axis servohydraulic test facility together with a parameter sensitivity analysis of the closed loop control system. Based on nonlinear model equations including the servohydraulic actuator dynamics and the test table and payload mechanics a global nonlinear diffeomorphism is derived which maps the model equations into nonlinear canonical form. Using symbolic languages, a nonlinear control law is developed and calculated based on exact linearization techniques. The efficiency of this control concept with respect to tracking and decoupling behaviour of the test facility is demonstrated by computer simulations, taking into account parameter variations of the controllers. The applicability of this control approach to test facilities from industrial practice is discussed in detail