Gain-scheduled control of an underwater vehicle using quasi-LPV techniques

In this paper, the longitudinal control problem of an underwater vehicle undergoing obstacle avoidance, with large velocity variation, is considered and a gain-scheduled design is presented as a solution. Vehicle dynamics are transformed into a quasi-linear parameter varying form first. Then, the longitudinal control is constructed in two layers. The outer loop plays the role of guidance offering desired velocity command, which is tracked by the inner loop of the control law. The linear parameter varying (LPV) methodology used in the inner loop design circumvents the use of difficult nonlinear control techniques, and cancels the effects of velocity dependent terms. Furthermore, a simplified implementation scheme employing switched LPV control is investigated. Nonlinear simulation demonstrates the effectiveness of the proposed approach.