Kim Jihun, Nam Kimoon, Yang Seungtae, Moon Junyoung, Yang Jaeha, Ryu Jaewook, Lee Giuk
Mechanical Engineering Department, Chung-Ang University, Seoul, Republic of Korea.
HUROTICS Inc., Seoul, Republic of Korea.
Soft Robot. 2025 Apr;12(2):200-212. doi: 10.1089/soro.2023.0028. Epub 2024 Sep 30.
Wearable robots have been developed to assist the physical performance of humans. Specifically, exosuits have attracted attention due to their lightweight and soft nature, which facilitate user movement. Although several types of force controllers have been used in exosuits, it is challenging to control the assistive force due to the material's softness. In this study, we propose three methods to improve the performance of the basic controller using an admittance-based force controller. In method A, the cable was controlled according to the user's thigh motion to eliminate delays in generating the assistive force and improve the control accuracy. In method B, the stiffness feedforward model of the human exosuit was divided into two independent models based on the assistance phase for compensating the nonlinear stiffness more accurately. In method C, the real-time optimization method for the stiffness feedforward model with an adaptive moment estimation method optimizer was proposed. To validate these methods' effectiveness, we designed three new controllers, gradually combined the proposed methods with the basic controller, and compared their performances. We found that controller III, combining all three methods with the basic controller, showed the best performance. By applying controller III in the same exosuit, the root-mean-square error of the assistive force decreased from 39.84 N to 13.72 N, reducing the error by 65.56% compared with the basic controller. Moreover, the time delay for force generation in the gait cycle percentage decreased from 9.99% to 3.41%, reducing the delay by 65.87% compared with the basic controller.
可穿戴机器人已被开发用于辅助人类的身体活动。具体而言，外骨骼套装因其轻便和柔软的特性而受到关注，这有利于用户的行动。尽管外骨骼套装中已经使用了几种类型的力控制器，但由于材料的柔软性，控制辅助力具有挑战性。在本研究中，我们提出了三种方法，以使用基于导纳的力控制器来提高基本控制器的性能。在方法A中，根据用户的大腿运动来控制缆线，以消除产生辅助力时的延迟并提高控制精度。在方法B中，基于辅助阶段将人体外骨骼套装的刚度前馈模型分为两个独立模型，以便更准确地补偿非线性刚度。在方法C中，提出了一种使用自适应矩估计方法优化器对刚度前馈模型进行实时优化的方法。为了验证这些方法的有效性，我们设计了三种新的控制器，将所提出的方法逐步与基本控制器相结合，并比较它们的性能。我们发现，将所有三种方法与基本控制器相结合的控制器III表现出最佳性能。通过在同一外骨骼套装中应用控制器III，辅助力的均方根误差从39.84 N降至13.72 N，与基本控制器相比，误差降低了65.56%。此外，步态周期百分比中力产生的时间延迟从9.99%降至3.41%，与基本控制器相比，延迟降低了65.87%。
