Depth and pitch control of USM underwater glider: Performance comparison PID vs. LQR

Present study consists the design of an optimal state feedback controller for our USM Underwater Glider (USMGlider). The glider mathematical model for motion control is obtained using MATLAB System Identification Toolbox, where ballast pumping rate is an input signal to the system. Different parameters were observed independently, the pitching angle, and the depth. Two different models were obtained for the respective observations that relates ballast pumping rate to pitching angle and depth. From the transfer obtained, we apply a Linear Quadratic Regulator (LQR) and PID control schemes to observe the performance of the controllers over the pitching angle, and the depth. The optimal performances are obtained via tuning of Qs and Rs matrices of the LQR and gain of K_p, K_i and K_d of the PID controller. The results show both controllers provide satisfactory performance.