School of Engineering, University of Kent, Canterbury, CT2 7NT, UK.
School of Engineering, Technology and Design, Canterbury Christ Church University, Canterbury, CT1 1QU, UK.
Sensors (Basel). 2023 Jul 2;23(13):6103. doi: 10.3390/s23136103.
Children with cerebral palsy (CP) experience reduced quality of life due to limited mobility and independence. Recent studies have shown that lower-limb exoskeletons (LLEs) have significant potential to improve the walking ability of children with CP. However, the number of prototyped LLEs for children with CP is very limited, while no single-leg exoskeleton (SLE) has been developed specifically for children with CP. This study aims to fill this gap by designing the first size-adjustable SLE for children with CP aged 8 to 12, covering Gross Motor Function Classification System (GMFCS) levels I to IV. The exoskeleton incorporates three active joints at the hip, knee, and ankle, actuated by brushless DC motors and harmonic drive gears. Individuals with CP have higher metabolic consumption than their typically developed (TD) peers, with gravity being a significant contributing factor. To address this, the study designed a model-based gravity-compensator impedance controller for the SLE. A dynamic model of user and exoskeleton interaction based on the Euler-Lagrange formulation and following Denavit-Hartenberg rules was derived and validated in Simscape and Simulink with remarkable precision. Additionally, a novel systematic simplification method was developed to facilitate dynamic modelling. The simulation results demonstrate that the controlled SLE can improve the walking functionality of children with CP, enabling them to follow predefined target trajectories with high accuracy.
脑瘫儿童由于活动能力和独立性受限，生活质量降低。最近的研究表明，下肢外骨骼（LLE）具有显著提高脑瘫儿童行走能力的潜力。然而，专为脑瘫儿童设计的 LLE 原型数量非常有限，而没有专门为脑瘫儿童设计的单腿外骨骼（SLE）。本研究旨在通过设计第一个可调节尺寸的脑瘫儿童 SLE 来填补这一空白，适用于 8 至 12 岁的脑瘫儿童，涵盖了粗大运动功能分类系统（GMFCS）的 1 至 4 级。外骨骼在臀部、膝盖和脚踝处集成了三个主动关节，由无刷直流电机和谐波传动齿轮驱动。脑瘫儿童的代谢消耗比其典型发育（TD）同龄人更高，而重力是一个重要的促成因素。为了解决这个问题，研究为 SLE 设计了基于模型的重力补偿阻抗控制器。根据 Euler-Lagrange 公式和 Denavit-Hartenberg 规则，基于用户和外骨骼交互的动力学模型被推导出并在 Simscape 和 Simulink 中进行了验证，精度非常高。此外，还开发了一种新颖的系统简化方法，以促进动态建模。仿真结果表明，受控制的 SLE 可以改善脑瘫儿童的行走功能，使他们能够高精度地遵循预设的目标轨迹。
