ABSTRACT
This paper presents the development of an optimal control strategy for a remotely piloted underwater towed vehicle. The objective of this controller is to allow the towed vehicle to fly a predetermined trajectory over the sea floor, while maintaining a close to constant attitude in space. Linear, quadratic optimal control is used to optimize the vehicle performance by varying the weighting of the errors between the actual and desired values of the states and inputs of the system. The linearized system is shown to be controllable and observable. A full state feedback design is then assessed, showing the role of the performance integral and the state and control weighting matrices. A simplified reference model provides the required tracking capability, and a full state observer provides an estimate of all the states based on a limited number of measured states. The effects of actuator saturation are modelled, and a type of variable structure control is shown to be effective in maintaining stability.
