Adaptive cascade control of a hydraulic actuator with an adaptive dead-zone compensation and optimization based on evolutionary algorithms

This work presents an adaptive cascade controller tuned by using evolutionary algorithms for the trajectory tracking control of a hydraulic actuator with an overlapped proportional valve. The hydraulic actuator mathematical model includes the dead-zone nonlinearity due to the use of the overlapped valve. By considering the hydraulic actuator as a mechanical subsystem driven by a hydraulic one, a cascade strategy is proposed. Such cascade strategy is based on the order reduction and allows one to propose different control laws for each subsystem. Adaptive algorithms are used to compensate the parametric uncertainties in the hydraulic and mechanical subsystems including an adaptive compensation for the valve dead-zone. In the sequence, evolutionary algorithms are used to tune the proposed controller for performance optimization. Simulation results illustrate the main characteristics of the proposed controller and the performance of the evolutionary algorithm called differential evolution in tuning of proposed controller.