Fixed-Time Sliding Mode Control for Pneumatic Artificial Muscles-Driven Robotic Finger With Prescribed Performance

Pneumatic artificial muscles (PAMs) are widely used in robotics due to their high power-to-weight ratio and compliance, but their inherent nonlinearity and uncertainties pose significant control challenges. This paper proposes a fixed-time sliding mode control strategy with prescribed performance (PP-FTSMC) for PAMs-driven robotic finger, which can ensure accurate and stable control. The prescribed performance framework is introduced to constrain the tracking error within predefined bounds, which achieves improved transient and steady-state performance. By incorporating unilateral constraint functions, the proposed method ensures safe operation through air pressure regulation. Additionally, the designed controller ensures fixed-time stability, and Lyapunov theory is used to rigorously analyze its stability. Simulation results demonstrate the superiority of the proposed algorithm in terms of convergence speed and tracking accuracy.