In context
In early 2025, pneumatic artificial muscles (PAMs) were gaining traction in robotics for their lightweight, high force-to-weight ratio, and inherent compliance, particularly for applications requiring soft interaction such as rehabilitation and biomimetics. However, their nonlinear hysteresis and the coordination challenges in multi-arm parallel configurations limited control precision, prompting research into advanced compensation and synchronization strategies.
What was reported
A study from Nankai University proposed a synchronous control method for PAM-actuated parallel robots, addressing hysteresis and motion coordination. The team modified the Bouc-Wen hysteresis model by adding polynomial and auxiliary terms to better capture the asymmetric input-output relationship of PAMs, then applied its inverse model for feedforward compensation.
To enhance synchronization, they established error signal transmission between robotic arms and designed an adaptive pressure controller within a fully actuated system framework, ensuring asymptotic convergence of both tracking and synchronization errors. Stability analysis was completed, and comparative hardware tests demonstrated superior hysteresis fitting and tracking accuracy versus existing methods.
The approach directly uses air pressure as the control input, simplifying the model by avoiding conversion to state-space form, and accounts for the robot's fully actuated nature.
Why it mattered
This work offered a practical solution to improve precision in soft-actuated parallel robots, potentially expanding their use in delicate tasks like medical rehabilitation and human-robot interaction, where accurate, synchronized motion is critical.
"The comparative results show that the fitting accuracy of the proposed hysteresis model and the tracking accuracy of the proposed control method are superior to the comparative method, fully verifying the feasibility of the proposed method."
Source: 《机器人》期刊 (robot.sia.cn) · Published 2025-03-15 · “基于迟滞逆补偿的气动人工肌肉并联机器人同步控制”