IEEE Trans Biomed Eng. 2021 Apr;68(4):1351-1359. doi: 10.1109/TBME.2020.3027823. Epub 2021 Mar 18.
Patients after stroke may have different rehabilitation needs due to various levels of disability. To satisfy such needs, a performance-based hybrid control is proposed for a cable-driven upper-limb rehabilitation robot (CDULRR). The controller includes three working modes, i.e., resistance mode, assistance mode and restriction mode, which are switched by the tracking error since it is a common index to represent motor performance. In resistance mode, the proper damping force would be provided for subjects, which is in the opposite direction to the actual velocity. In assistance mode, a method of adjusting stiffness coefficient by fuzzy logic is adopted to provide suitable assistance to help subjects. In restriction mode, the damping force is applied again to limit the movement and ensure the safety. To verify the effectiveness of the controller, the task-oriented experiments with different disturbance were conducted by ten healthy subjects. The experiments results demonstrated that the controller can adjust working modes by the subjects' motor performance. It was found that, as the increasing disturbance led to a decrease in the motor performance, the robot provided more assistance in the trainings. Adaptive adjustment of damping force and stiffness coefficient allowed the controller to induce more active effort.
脑卒中患者由于残疾程度不同，康复需求也不同。为了满足这些需求，提出了一种基于性能的混合控制方法，用于控制缆索驱动上肢康复机器人（CDULRR）。该控制器有三种工作模式，即阻力模式、辅助模式和限制模式，通过跟踪误差进行切换，因为跟踪误差是表示电机性能的常用指标。在阻力模式下，为受试者提供适当的阻尼力，该阻尼力与实际速度相反。在辅助模式下，采用模糊逻辑调整刚度系数的方法，为受试者提供适当的辅助。在限制模式下，再次施加阻尼力来限制运动，以确保安全。为了验证控制器的有效性，通过十位健康受试者进行了具有不同干扰的面向任务的实验。实验结果表明，该控制器可以根据受试者的运动性能来调整工作模式。结果发现，随着干扰的增加导致运动性能下降，机器人在训练中提供了更多的辅助。阻尼力和刚度系数的自适应调整使控制器能够诱导更多的主动努力。
