Pitch Angle Active Disturbance Rejection Control with Model Compensation for Underwater Glider

Underwater glider is a strong coupling and nonlinear system. Most current methods neglect the influences from the buoyancy adjustment system to pitch angle so that there always a large overshoot in the pitch angle control loop. In order to improve the control accuracy for pitch angle, a model compensation (MC) based on the Active disturbance rejection control (ADRC) was proposed in this paper. The Extended State Observer (ESO) estimated system comprehensive disturbances and avoided the influences from the perturbation by giving disturbance compensation. ADRC obtained segmental models through system modeling, estimation and physical sensors measurement. The estimation pressure of ESO was greatly reduced and the estimation precision was improved significantly. Simulations in the MATLAB indicated that MC-ADRC have a good control precision and low overshoot with settling time for glider systems. It reduced 4.5% overshoot and dropped the settling time to 90 s for pitch angle control than the traditional ADRC.