Path-Following Based on Fuzzy Line-of-Sight Guidance for a Bionic Snake Robot With Unknowns

To improve the convergence rate of path-following errors of a bionic snake robot and reduce the overshoot of kinematic errors, a path-following control method based on fuzzy line-of-sight (LOS) guidance for a bionic snake robot with unknowns is developed. This method designs the time-varying LOS forward distance and sliding mode switching gain according to fuzzy rules, offsets the external interferences, weakens the damage of chattering to robot joints, and reduces the negative impact of external interferences on the robot path-following. In addition, the uncertain friction coefficients are predicted by using the adaptive estimation, which compensates for joints' rotating force inputs and improves environmental adaptability of the body. By establishing the appropriate Lyapunov function, the stability of the gait angle, motion position, and whole system are verified. Simulation and experiment results show the feasibility and superiority of the proposed method.