基于上臂关节角度和肌电信号的二自由度假肢控制方法

Control of a Two-DOF Prosthetic Hand by Upper Limb Joint Angles and EMG Signal

肌电信号的采集易受到空气湿度和皮肤表面汗液等多种随机因素的干扰,使采集到的肌电信号极不稳定.为了应对此问题,市售的肌电假肢普遍采用基于开关量的控制方法,但是开关量对多自由度假肢的控制依赖于顺序动作切换,这使得假肢的实际使用过程比较繁琐.利用肢体运动学信息的假肢控制方法常见于下肢假肢,这是因为上肢的运动受抓取物体的形状和位置等因素变化,其肢体运动的规律性较差.本文提出一种利用上臂关节角度和肌电信号的控制方法,利用人体在抓握时肩关节的运动模式区分使用者对不同形状物体的抓握,并将此方法应用在二自由度假肢的控制中.通过与开关量控制的假肢在日常物品抓握实验中的对比,表明本文所提出方法在稳定性和使用效率方面都优于开关量控制的方式.

The EMG signal is affected by air humidity, sweat, and many other factors, therefore, it is not stable for long time usage. To cope with this shortage, EMG based prosthetic hands available in the market are usually controlled by the on/off strategy. However, this strategy is not sophisticated for controlling prosthetic hands with multi-DOFs.Kinematics information is frequently used in controlling lower limb prostheses instead of upper limb ones because of the object-oriented feature of the motion of the upper limb. In this paper, we propose a control strategy which identifies the fetching motion of the user from his/her shoulder joint. An experiment is conducted to show the stability and easy-use of the proposed strategy in comparison with the on/off strategy.