A Robotic Exoskeleton Device for Augmenting Wrist Movement and Grip Function in Debilitated Patients

Many diseases and conditions can cause reduced motor function in joints throughout the body. This paper identifies such health issues that affect the function of the wrist and hand in particular. After identifying these conditions, a concept three degree of freedom (two DOFs of the wrist plus cylindrical grip) robotic exoskeleton design is presented that is intended to augment a patient’s remaining function and strength while remaining portable and lightweight. With this in mind, the device is intended to allow a patient to use and operate it independently, without the presence of a therapist. The mechanical design of the exoskeleton is described in depth, along with details of potential actuation methods. The main idea for control of the device is to detect small torque values as a patient attempts a movement and in turn predict what the intended outcome would be if the patient were at full strength. After processing this information the robot would assist the patient in facilitating the anticipated movement. This is in contrast to alternate control methods, which rely primarily on electromyography (EMG) to detect signals to muscles that control certain movements. Electromyography can be unreliable because many of the conditions that cause debilitated function also cause an interruption or break in these signals.