Design and analysis of a portable wrist rehabilitation instrument based on Bricard linkage

In this paper, a portable wrist rehabilitation instrument based on the Bricard linkage is presented. The instrument functions through the spatial tumbling of the Bricard linkage. The movement has similarities with wrist kinematics and is designed to guide wrist rehabilitation. First, the mechanical scheme of the instrument is presented. The wrist kinematics is analyzed, which are flexion & extension, ulnar & radial deviation. Second, for the reason that the movements of the Bricard linkage are similar to that of the Schatz linkage, the kinematic of the instrument is analyzed through the Schatz linkage. Third, the energy consumption of the instrument is calculated and a corresponding wrist rehabilitation exercise is choreographed. Finally, a prototype is manufactured, and a series of experiments are carried out. The results validate that the wrists could be guided by the instrument. The wrists could be fully exercised, and the efficiency of the rehabilitation would be evaluated by the energy consumption in the wrist exercise.