Path Planning and Control for Underwater Vehicle Driven by an Ionic Polymer Metal Composite (IPMC) Actuator

This paper presents an approach for trajectory planning and control of an underwater vehicle within obstacles. The vehicle is driven by a single IPMC actuator that goes through oscillatory locomotion. The presented work is divided into kinematic path planning and trajectory control sections. In the kinematic path planning phase, the vehicle is approximated by a rectangle that encloses the largest deformation of the oscillating IPMC actuator. Obstacles are approximated by polygonal shapes that approximate their actual dimensions. To simplify the problem of collision detection, vehicle is shrunk to a line while obstacles are expanded by a half width of the rectangle representing the vehicle. Path planning problem is formulated as a nonlinear programming problem that minimizes the error between current and goal configurations of the vehicle. The objective function combines the distance to target and the orientation of the vehicle. A penalty term is added to the objective function to ensure that the vehicle is not colliding with obstacles. The obtained path is discretized with respect to time, and controlled simultaneously for the yaw angle and speed of the vehicle. These two controllers are designed based on the simulation data from the dynamic model of the IPMC propelled vehicle. This proposed approach can be used in real time implementation of vehicle trajectory control in the presence of obstacles.