Predefined Time Nonsingular Fast Terminal Sliding Mode Control for Trajectory Tracking of ROVs

A predetermined time nonsingular fast terminal sliding mode control (PTNFTSMC) is proposed to solve the problem of long convergence time and instability in the orbit control of remotely operated vehicles (ROVs). First, a new concise method is proposed to design a predetermined-time controller by setting control parameter conditions that self-adjust according to the system state. Then, the control law of PTNFTSMC is formulated by combining the proposed theory of prescribed time control and the theory of fast termination nonsingular sliding control mode. Finally, the stability and tunability of the proposed controller in a specific period are demonstrated by rigorous arguments. Simulation experiments show that the proposed PTNFTSMC achieves stability at any initial state of the system for a specified time with guaranteed convergence accuracy, and the actual convergence time of the system is very close to the parameters of the specified time compared with other existing control schemes. This confirms the effectiveness and superiority of the proposed PTNFTSMC.