This article presents the system integration, sensing, and control of a novel modular soft-rigid pneumatic exoskeleton for lower limb. The proposed exoskeleton consists of three soft hinges (to drive the hip, knee, and ankle joints) and four rigid links (aligned with the waist, thigh, crus, and foot). Each soft hinge is made of and actuated by a customized bidirectional curl pneumatic artificial muscle (CPAM), whereas the links are three-dimensional printed. Each of the rigid links combined with its lower soft hinge (if any) is made into an independent soft-rigid module, that is, the waist-hip, thigh-knee, crus-ankle, and foot modules. With each of the modules are multiple sensors integrated, including two pressure sensors for detecting the inflating pressures, and two flex sensors and an inertia measurement unit for estimating the bending angles of the soft hinges via data fusion. Through a data-fitted angle–torque–pressure relationship of the CPAM, the actuation torque is estimated. An external electropneumatic control system is also developed. The double closed-loop control system consisting of pressure servos and position/torque controllers is designed to control the bending angles and actuation torques of the exoskeleton hinges. Experiment shows good motion controllability of the proposed exoskeleton in the range of motion of a gait cycle.

中文翻译：

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模块化，刚性气动下肢外骨骼的集成，传感和控制。

本文介绍了一种用于下肢的新型模块化软刚性气动外骨骼的系统集成，传感和控制。拟议中的外骨骼由三个软铰链（用于驱动髋，膝和踝关节）和四个刚性链接（与腰部，大腿，腿和脚对齐）组成。每个软铰链均由定制的双向卷曲气动人工肌肉（CPAM）制成并由其致动，而链节则是三维打印的。每个刚性链节及其下部的软铰链（如果有）组合成一个独立的软刚性模块，即腰臀，大腿膝盖，脚踝和脚模块。每个模块都集成了多个传感器，包括两个用于检测充气压力的压力传感器，两个挠曲传感器和一个惯性测量单元，用于通过数据融合估计软铰链的弯曲角度。通过CPAM数据拟合的角度-扭矩-压力关系，可以估算致动扭矩。还开发了外部电动控制系统。由压力伺服器和位置/扭矩控制器组成的双闭环控制系统旨在控制外骨骼铰链的弯曲角度和致动扭矩。实验表明，所提出的外骨骼在步态周期的运动范围内具有良好的运动可控性。由压力伺服器和位置/扭矩控制器组成的双闭环控制系统旨在控制外骨骼铰链的弯曲角度和致动扭矩。实验表明，所提出的外骨骼在步态周期的运动范围内具有良好的运动可控性。由压力伺服器和位置/扭矩控制器组成的双闭环控制系统旨在控制外骨骼铰链的弯曲角度和致动扭矩。实验表明，所提出的外骨骼在步态周期的运动范围内具有良好的运动可控性。