Development Of Exoskeletons For Pathological Tremor Suppression Of Wrist And Hand

Pathological tremor is caused by a variety of neurological diseases and has a very high incidence in the elderly.Although it is not life-threatening,it brings great inconvenience to patients.Traditional treatments including medication,rehabilitation programs and deep brain stimulation(DBS)have shown limited effectiveness along with risks and side effects.In order to overcome the limitations of these treatments,two wearable exoskeletons for wrist tremor suppression and hand tremor suppression are designed based on robotic exoskeleton technology,aiming at providing a new solution for the tremor management of patients with pathological tremor.The wrist tremor suppression exoskeleton(WTSE)has one degree of freedom and works in semi-active control mode.A magnetorheological(MR)fluid damper is designed for controllable damping force.The total weight of the WTSE is 262.13 g.The prototype is wearable and the damping force is real-time adjustable.The analysis of the damping force and the magnetic field distribution of the MR damper assists the structural design.An embedded acquisition platform based on IMU and STM32 is built to acquire tremor information and adjust the damping force in real time.According to the experimental results,the signal acquisition system can obtain reliable data and the maximum continues initial damping force reaches 8 N.Besides,the WTSE can reduce the amplitude of acceleration and angular velocity of simulated tremor by 60.39% and 55.07%,respectively.The hand tremor suppression exoskeleton(HTSE)based on light linear motor works in the passive tremor suppression mode.It has five degrees of freedom and underdrives 10 degrees of freedom of human hand.The exoskeleton is designed with complex surface which ensures the wearability.The total weight of the HTSE is 213.23 g and the exoskeleton is portable.By analyzing and simulating the kinematics and dynamics of the driving mechanism,the relationship of parameters between the angle joints of the fingers and the input of the motors has been got,and the relationship of parameters between the expected joints force and required driving force has also been investigated.The designed embedded control platform can control and drive the exoskeleton.According to the experimental results,the HTSE has a good driving ability.It can reduce the amplitude of finger angle of simulated hand tremor by 76% to 95%.Besides,it can reduce the amplitude of finger angle of patient’s hand tremor by 66% to 85%.