In a parallel development to traditional rigid rehabilitation robotic systems, cable-driven systems are becoming popular. The robowalk expander product uses passive elastic bands in the training of the lower limbs. However, a well-controlled assistance or resistance is desirable for effective walking relearning and muscle training. To achieve well-controlled force during locomotion training with the robowalk expander, we replaced the elastic bands with actuator-driven cables and implemented force control algorithms for regulation of cable tensions. The aim of this work was to develop an active cable-driven robotic system, and to evaluate force control strategies for walking rehabilitation using frequency-domain analysis. The system parameters were determined through experiment-assisted simulation. Then force-feedback lead controllers were developed for static force tracking, and velocity-feedforward lead compensators were implemented to reduce velocity-related disturbances during walking. The technical evaluation of the active cable-driven robotic system showed that force-feedback lead controllers produced satisfactory force tracking in the static tests with a mean error of 5.5%, but in the dynamic tests, a mean error of 13.2% was observed. Further implementation of the velocity-feedforward lead compensators reduced the force tracking error to 9% in dynamic tests. With the combined control algorithms, the active cable-driven robotic system produced constant force within the four cables during walking on the treadmill, with a mean force-tracking error of 10.3%. This study demonstrates that the force control algorithms are technically feasible. The active cable-driven, force-controlled robotic system has the potential to produce user-defined assistance or resistance in rehabilitation and fitness training.

中文翻译：

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开发用于步行康复的主动电缆驱动、力控机器人系统

在与传统刚性康复机器人系统并行发展的过程中，电缆驱动系统正在变得流行。robowalk扩张器产品在下肢训练中采用被动弹力带。然而，为了有效地重新学习步行和肌肉训练，需要良好控制的辅助或阻力。为了在使用 robowalk 扩张器进行运动训练期间实现良好的力控制，我们用执行器驱动的电缆取代了松紧带，并实施了力控制算法来调节电缆张力。这项工作的目的是开发一种主动电缆驱动机器人系统，并使用频域分析评估步行康复的力控制策略。通过实验辅助模拟确定系统参数。然后开发了用于静态力跟踪的力反馈超前控制器，并实施了速度前馈超前补偿器以减少行走过程中与速度相关的干扰。主动电缆驱动机器人系统的技术评估表明，力反馈主导控制器在静态测试中产生了令人满意的力跟踪，平均误差为 5.5%，但在动态测试中，观察到平均误差为 13.2%。速度前馈超前补偿器的进一步实施将动态测试中的力跟踪误差降低至 9%。通过组合控制算法，主动电缆驱动机器人系统在跑步机上行走时，在四根电缆内产生恒定的力，平均力跟踪误差为 10.3%。这项研究表明力控制算法在技术上是可行的。主动电缆驱动、力控制的机器人系统有可能在康复和健身训练中产生用户定义的帮助或阻力。