Four‐fingered lightweight exoskeleton robotic device accommodating different hand sizes

A wearable hand exoskeleton (EXO) device that permits exertion of bidirectional forces on finger phalanges throughout the human finger workspace is proposed. The novelty of the proposed device lies in its direct‐driven, portable and optimised mechanism with the ability to adjust variable hand sizes in addition to other distinguishing features. The adjustable link lengths and structure of the device have emerged from kinematic‐based optimisation criterion, which targets the natural finger workspace. The selection of actuators for the EXO is backed by the results of experiments conducted using appropriate sensory instrumentation to measure the force exertion levels of a human hand. A four‐fingered prototype of the EXO is designed and fabricated. The device is then subjected to various test inputs to characterise the tracking performance. Preliminary results demonstrate that the proposed device can flex and extend the fingers following accurate trajectories.