Subsea vehicle path planning using nonlinear programming and constructive solid geometry

Concerns the finding of a collision-free path for an unmanned underwater vehicle (UUV) and manipulator, from an initial to a goal configuration, around subsea structures. The paper concentrates on efficient searching and object representation, while removing local minima. An approach to path planning using a nonlinear programming approach is presented. The free space of the workspace is represented as a set of inequality constraints of a nonlinear programming problem, using vehicle configuration variables. The goal configuration is designed as the unique global minimum point of the objective function. The initial configuration is the start point for the nonlinear search. The numerical algorithm developed for solving the nonlinear programming problem is applied. Every immediate point generated guarantees that it is in the free space and, therefore, is collision free. Mathematical foundations for constructive solid geometry, Boolean operations and approximation techniques are developed and are used to represent the free space of the robot workspace as a set of inequalities. Techniques which guarantees convergence, efficiency and numerical robustness can be applied directly to the problem. Simulation results show its effectiveness, efficiency and potential as an online motion planner