Development of a compliant hand assistive device

A hand assistive device that assists people with limited ability to grip with their fingers is proposed here. The device allows free movement of the fingers and the wrist regardless of the device´s operational state. The concepts were developed to be lightweight and portable. A cable drive mechanism is used to provide an assistive downward force for the middle phalanx of the finger while the user grips an object. This resembles the functionality of tendons that attach human muscles to bones. The power transmission mechanism involves a differential mechanism that uses a spring to transfer the force of a linear actuator as cable tension. The prototype is implemented on the dorsal side of the hand and it allows for free movement of the fingers when the device is not in use.