Design and Simulation of an Underactuated Finger Rehabilitation Exoskeleton based on Bionic Kinematics

Abstract

Nowadays, stroke is the leading cause of death and disability in China, and the disability rate exceeds 80%. Approximately 80% of patients have upper limb functional disorders, and the impairment of fine hand movements is particularly significant. The effect of traditional rehabilitation treatment is limited, and the existing finger exoskeletons have problems such as insufficient bionics and poor adaptability to daily scenarios, which restrict the clinical rehabilitation effect. In response to the problem that finger rehabilitation exoskeletons can achieve a high degree of bionics and be close to daily life, based on the bionic principle of the four-bar linkage mechanism, a design scheme for an under-actuated finger rehabilitation exoskeleton with a serial topological transmission of connecting rods is proposed. The device uses an aviation aluminum alloy frame. The stiffness of the key load-bearing parts reaches 18 GPa, and the weight is less than 200 g. Compared with traditional stainless steel materials, the mass is reduced by 42%. Simulate the coordinated relationship between adjacent phalanges during the flexion and extension movements of human fingers, achieve multi-joint linkage driven by a single power source, and it is suitable for the rehabilitation of hand motor function in stroke patients. Based on the patients' grasping needs in various life scenarios, kinematic simulations and analyses of grasping small balls made of rubber, oak, and stainless steel were carried out. The feasibility of the design of an underactuated finger rehabilitation exoskeleton based on bionic kinematics was verified.