A Force-Controllable Compact Actuator Module for a Wearable Hand Exoskeleton

In this paper, a force-controllable compact actuator module for a wearable hand exoskeleton system is proposed. To interact with virtual objects naturally with a hand exoskeleton, a small actuator module, which can generate the desired force accurately, is highly required. In the proposed actuator module, a series elastic actuator (SEA) mechanism was applied for the force mode control. Based on the experimental analysis about grip forces, a spring was manually designed and a linear motor was selected. A manually designed motor driver was also embedded to the actuator module. The actually manufactured actuator module was compact enough to put five modules at the back of the hand. For precise force mode control, friction of the motor was identified and compensated. Using a PID controller with the friction compensation, the proposed actuator module could generate the desired force accurately with actual finger movements.