Zhou Jie, Peng Huanfeng, Su Steven, Song Rong
IEEE Trans Biomed Eng. 2023 Jun;70(6):1858-1868. doi: 10.1109/TBME.2022.3230784. Epub 2023 May 19.
Compliance control is crucial for physical human-robot interaction, which can enhance the safety and comfort of robot-assisted rehabilitation. In this study, we designed a spatiotemporal compliance control strategy for a new self-designed wearable lower limb rehabilitation robot (WLLRR), allowing the users to regulate the spatiotemporal characteristics of their motion. The high-level trajectory planner consists of a trajectory generator, an interaction torque estimator, and a gait speed adaptive regulator, which can provide spatial and temporal compliance for the WLLRR. A radial basis function neural network adaptive controller is adopted as the low-level position controller. Over-ground walking experiments with passive control, spatial compliance control, and spatiotemporal compliance control strategies were conducted on five healthy participants, respectively. The results demonstrated that the spatiotemporal compliance control strategy allows participants to adjust reference trajectory through physical human-robot interaction, and can adaptively modify gait speed according to participants' motor performance. It was found that the spatiotemporal compliance control strategy could provide greater enhancement of motor variability and reduction of interaction torque than other tested control strategies. Therefore, the spatiotemporal compliance control strategy has great potential in robot-assisted rehabilitation training and other fields involving physical human-robot interaction.
柔顺控制对于人机物理交互至关重要，它可以提高机器人辅助康复的安全性和舒适性。在本研究中，我们为新设计的可穿戴下肢康复机器人（WLLRR）设计了一种时空柔顺控制策略，允许用户调节其运动的时空特征。高级轨迹规划器由轨迹生成器、交互扭矩估计器和步态速度自适应调节器组成，可为WLLRR提供空间和时间柔顺性。采用径向基函数神经网络自适应控制器作为低级位置控制器。分别对五名健康参与者进行了被动控制、空间柔顺控制和时空柔顺控制策略的地面行走实验。结果表明，时空柔顺控制策略允许参与者通过人机物理交互调整参考轨迹，并可根据参与者的运动表现自适应地修改步态速度。研究发现，与其他测试控制策略相比，时空柔顺控制策略可以更大程度地增强运动变异性并降低交互扭矩。因此，时空柔顺控制策略在机器人辅助康复训练和其他涉及人机物理交互的领域具有巨大潜力。
