In order to stimulate the patients' active participation in the process of robot-assisted rehabilitation training of stroke patients, the rehabilitation robots should provide assistant torque to patients according to their rehabilitation needs. This paper proposed an assist-as-needed control strategy for wrist rehabilitation robots. Firstly, the ability evaluation rules were formulated and the patient's ability was evaluated according to the rules. Then the controller was designed. Based on the evaluation results, the controller can calculate the assistant torque needed by the patient to complete the rehabilitation training task and send commands to motor. Finally, the motor is controlled to output the commanded value, which assists the patient to complete the rehabilitation training task. The control strategy was implemented to the wrist function rehabilitation robot, which could achieve the training effect of assist-as-needed and could avoid the surge of assistance torque. In addition, therapists can adjust multiple parameters in the ability evaluation rules online to customize the difficulty of tasks for patients with different rehabilitation status. The method proposed in this paper does not rely on the information from force sensor, which reduces development costs and is easy to implement.
在康复机器人辅助脑卒中患者进行康复训练时，为激发患者的主动参与意识，康复机器人应按照患者康复需求提供其所需的辅助力矩。本文针对腕功能康复机器人提出一种按需辅助控制策略：首先制定能力评估规则，并依据该规则评估患者能力；然后设计控制器，控制器可基于评估结果求解出患者完成康复训练任务所需的辅助力矩，并下发指令至电机；最后控制电机输出指令值，辅助患者完成康复训练任务。将该控制策略应用于腕功能康复机器人，不仅实现了按需辅助的训练模式，而且能够避免辅助力矩激增，同时康复治疗师可在线调节能力评估规则中的多个参数，为不同康复状态的患者定制任务难度。本文所提方法不依赖于力学传感器信息，降低了开发成本且易于实现，具有一定的工程应用价值。.
Keywords: assist-as-needed; impedance control; minimum jerk trajectory; robot; wrist function-rehabilitation.