Design and kinematics of 4- DoF multi-purpose wearable mechanical arm (MUWA) support for enhanced operation stability

Abstract

A low-cost motor-less simple wearable mechanical arm support unit is presented as a viable alternative to todays assistive exoskeleton support units. By limiting the functionality of the device to stabilization rather than actuation, the cost could significantly be reduced while still maintaining a wide range of applications. The basic idea is to let the device follow the wearers actions freely without obscuring the motion in normal mode, while fixating the arm at the desired angle and location when the user expect to receive support; namely in lock mode. The lock-unlock mechanism is simple Bluetooth activated palm gesture of the non-operating arm while the support unit Bluetooth receiver stabilizes the arm at any desired angle or position in response to sensed gesture command. The lock-unlock mechanism is achieved by solely two solenoids, one at each of the joints; shoulder and elbow, with 3 Degree of Freedom (DoF) and 1 DoF respectively, leaving the wrist free to perform the desired hand operation and increasing the precision of the locking mechanism.