Enhancing trajectory tracking and energy efficiency in Pneumatic Servo Translational Parallel Manipulator with Frac-SMC-RFESO Control

Abstract

Pneumatic-driven systems often face significant energy consumption challenges, primarily due to compressed air leakage and inefficient utilization. To address these issues, this paper presents a comprehensive solution encompassing both hardware and software designs for a Pneumatic Servo Translational Parallel Manipulator (PS-TPM). On the software side, the proposed energy-efficient controller, Frac-SMC-RFESO, integrates fractional-order sliding mode control with a reduced fractional-order extended state observer (RFESO) to optimize the PS-TPM’s performance. This integration endows the Frac-SMC-RFESO with exceptional adaptability, enabling it to effectively manage the system’s complex dynamics and nonlinearities while minimizing energy consumption. Furthermore, by utilizing the RFESO, the controller estimates system uncertainties and disturbances within the PS-TPM, further enhancing trajectory tracking performance. In its mechanical design, the PS-TPM incorporates double-acting magnetic rodless cylinders paired with proportional directional control valves, improving sealing to prevent air leakage and thereby enhancing energy efficiency. Experimental results highlight the exceptional performance of the Frac-SMC-RFESO controller, achieving superior trajectory tracking while reducing energy consumption by 16% to 47% compared to the RLESO-SMC (an integer-order sliding mode controller with a reduced-order linear extended state observer), LADRC (a linear active disturbance rejection controller), and the PID controller.