Mixed sliding mode and PID approach of motion control for mobile robot

This paper shows that a comprehensive multivariable approach of autopilot design that mixes sliding mode and PID leads to robustly satisfactory results for underwater mobile robot. The 6-DOF linear equations of motion can be divided into three subsystems for speed control, steering, and diving. The sliding mode algorithm is designed for steering control and PID is used for diving and speed control. The mixed design of autopilot is proposed here for the combined control of underwater robot steering, depth and speed during complex flight maneuvers. A series of simulations based on the dynamics of an underwater robot illustrate the validity of the concept.