An integral terminal sliding mode-based adaptive control approach for traversing unknown inclined surfaces

Skid-steering control is commonly used in mobile robots, but its application to climbing manipulation-oriented robots (CMo-R) requires further development. This study proposes an adaptive skid-steering control strategy using an integral terminal sliding mode controller (ITSMC) to improve the climbing maneuverability of four-wheeled CMo-Rs on unknown inclined surfaces. The control law is developed using both kinematics and dynamics models, considering slipping effects to reduce slippage during 3D motion. A slip estimation and ITSMC-based adaptive control algorithm are introduced to enhance tracking accuracy in complex 3D environments. The proposed approach is compared to traditional PID and adaptive kinematic controllers through simulations and experiments. Results show that the proposed method outperforms the others in terms of tracking performance and robustness, especially for navigating horizontal, inclined, and vertical surfaces. This work provides a new control strategy for CMo-Rs, contributing to the feasibility and stability of future climbing manipulation applications.