Angle attitude control for a networked pneumatic muscle actuators system with input quantization: A prescribed-time nonlinear ESO approach

In this paper, angle attitude control is investigated for a networked pneumatic muscle actuators system (NPMAS) with input quantization and disturbance. A hysteretic quantizer is presented to effectively avoid the problem of high frequency oscillation in the process of quantization. A novel prescribed-time nonlinear extended state observer (PTNESO) is designed to continuously observe states and lumped disturbances of NPMAS, which ensures that the observation error converges in prescribed time. An active disturbance rejection control (ADRC) method based on PTNESO is designed to compensate for the lumped disturbances and achieve accurate angle tracking. A sufficient condition of bounded stability for NPMAS is given by the Lyapunov method. Finally, comparative experiments are provided to verify the effectiveness of the proposed control method.