Robust Constant Contact Force Control for Underwater Robot: A Sliding Mode Impedance Control Approach

In underwater robot operations, maintaining a stable contact force with the seabed is essential for interaction and inspection tasks. However, uncertainty in seabed position significantly affects control accuracy. To address this challenge, this paper proposes a robust impedance control strategy that improves disturbance rejection and enhances contact force precision. By incorporating a virtual control input and combining sliding mode control with disturbance observation within the impedance framework, the method enhances robustness. Simulations across diverse seabed conditions verify its effectiveness in reducing contact force fluctuations and improving motion stability.