Design Of A Wearable Ankle Joint Rehabilitation Orthosis

The joint rehabilitation orthosis is a robotic device which combines the robot technology and automation technology with the clinical rehabilitation medicine to assist or substitute therapists to complete the joint rehabilitation training. With the advantages of the flexibly adjustable speed, the high motion accuracy, continuous working ability and so on, it can not only provide precise, continuous and effective aids to patients in the rehabilitation training, but also solve the problems, such as the shortage of the physical therapists and the deficiency of manual training.The goal of this project is to develop a two degree-of-freedom wearable ankle joint rehabilitation orthosis that shall be able to assist or substitute therapists to conduct ankle joint rehabilitation training with convenience, comfort and safety.First of all, adequate researches of ankle rehabilitation devices from domestic and foreign institutions have been conducted for the subsequent studies on the physiological structure of human ankle joints, the injury mechanism of the inner and outer ligaments of the ankle joint and the rehabilitation training methods. Then a 2-DOF wearable ankle joint rehabilitation orthosis is designed using the double-tendon-sheath transmission system.Secondly, a torsion spring is designed to increase the flexibility and interference immunity of the device. This paper illustrates the design method, material selection, ANSYS simulation of the spring and the linear calibration experiment as well, which verifies the torsion spring’s feasibility as a torsion sensor.In addition, the D-H coordinate system and the coordinate transformation matrix are established based on the modeling analysis of the double-tendon-sheath transmission system whereby the overall modeling analysis of the wearable ankle rehabilitation device is conducted using Lagrange method. The kinetic characteristics of the device are discussed as well.Finally, an experimental platform of the device is set up for a series experiments based on the prototype of the ankle rehabilitation orthosis, and the hardware and software of the control system, which includes the trajectory tracking experiments, the moment step response experiments, the position frequency experiments and the isokinetic dynamometer experiments.