Adaptive control for a multi-axis hydraulic test rig

Multi-axis hydraulic rigs are widely used in industrial testing applications but still represent a challenging area for control system design. The current paper considers the control of a six-degrees-of-freedom multi-axis shaking table driven by six hydraulic actuators. The strategy adopted employs adaptive decentralized position control, i.e. each axis has its own adaptive controller. The scheme developed is based on a cascade minimal control synthesis (MCS) approach, which is a class of model reference adaptive control (MRAC). The theoretical background to the controller is presented, together with the results of an experimental study. Performance is compared with three other fixed-gain control schemes. The new adaptive scheme has superior disturbance rejection and command tracking capabilities.