The main purpose of this test-bed was to emulate faulty conditions on the hydraulic actuators to test a model-based fault detection algorithm. The two hydraulic actuators were connected back-to-back; one emulating the pitching control actuator and the other the wind load in a typical wind turbine.

We used Sliding-Mode control for the force and position control of the single-rod hydraulic cylinders. In retrospective, it was frightening to control the valves using this bang-bang strategy. Other than the undesirable noise from high frequency oscillation of the valves, force and position control were reliable and robust for the nonlinear dynamics and faulty conditions induced in the experiment.

Parallel robot for computer numerical control machining in 6 degrees of freedom. The attached box emulates loading conditions on the robot. The joints had huge mechanical play, which made the system very fun and challenging to control :)