Fixed-Time Sliding-Mode Reaching Based Trajectory Tracking Control of Unmanned Underwater Vehicles

For the fixed time trajectory tracking problem of unmanned underwater vehicles, a fixed time sliding mode reaching control law is proposed. The scheme combines the fixed time control strategy with the variable-gain sliding mode reaching control law together to guarantee the fixed time stability of the closed-loop system and fixed time convergence of signals. The chattering problem caused by sliding mode control gain is effectively suppressed. Numerical simulations demonstrate that the proposed control scheme can provide the control performance of finite time control, and a further improvement on system fast convergence is also provided.