Supple Lord - Passive Knee Rehabilitation Technology Research

With the constant development of the field of recovery, increasing patients who've received rehabilitation training after surgery for impaired knee-joint are believed to have good effect. The rehabilitation training is a compliant and controllable dynamic process from passive stage to semi-active stage and eventually to active stage, for the purpose of better rehabilitation effects. At present, most apparatus for recovery could only provide passive or active training, which fails to meet the requirement of entire rehabilitation process. In addition, rigid connection of electro motor and screw is widely adopted for supporting rehabilitation apparatuses, which may result in secondary damage to patients. And wearable rehabilitation apparatus is unsuitable for patients during early recovery periods. Consequently, there is important theoretic significance and application prospect to research rehabilitation apparatus for knee joint recovery with compliance passive and active training.In this thesis, passive-active compliant rehabilitation apparatus for knee joint recovery is proposed and designed. The compliance during the rehabilitation training process can be easily achieved utilizing pneumatic activation technology. The passive and active features during the training are generated due to the output force of this device acting as motive power or resist power. The main work of this thesis is as following:(1) The specific training items and the functional requirements of the rehabilitation apparatus in each rehabilitation stage after surgery are analyzed based on the structure model of human knee-joint. After that, the overall design requirement of knee-joint rehabilitation apparatus is proposed. The proposal of supporting rehabilitation apparatus is determined that patients should perform the recovery process while lying down and placing the impaired leg on this device, to meet the requirements during the whole rehabilitation course after the operation. This program proposed involves both passive and active recovery training pattern to patients. Besides, the compliance property of the apparatus keep the knee joint from a secondary damage to knee-joint during recovery process.(2) The deformation rate of conventional Mckibben compliant actuator is relatively low, which result in complex and bulk structure of rehabilitation apparatus. To solve the problem, a novel compliant pneumatic actuator with thrust force and large stroke was designed and implemented. The comparative large deformation rate is realized by overlapped multiple layers of elastic helical tube with initiated flat cross section. A static drive model of the pneumatic muscle is proposed based on theoretical analysis. Characteristic of the pneumatic muscle is studied and approved through experiments. The experiments turn out that high linear ability and less hysteresis phenomenon are achieved.(3) The structure of the passive-active rehabilitation apparatus for knee joint recovery is designed, which is composed of linear driving unit and bracket for the lower limbs. Using non-rod piston cylinder and compliant pneumatic actuator to build the linear driving unit is firstly proposed. The large stroke can be achieved by the non-rod piston cylinder, the size and the direction of cylinder output force is easily to be controlled. At the end of each knee bending, the apparatus is driven by the compliant pneumatic actuator to ensure the compliant and safety in this process. Length adjustment units are settled to adjust the length of the upper and lower leg bars in order to meet the needs of rehabilitation training of patients with different height.(4) The experimental system of the compliance passive-active rehabilitation apparatus for knee joint recovery is built, and the control program is established based on LabVIEW. Experimental study on the compliance of the pneumatic actuator is implemented, followed by the study of dynamic response characteristics of the non-rod piston cylinder, as well as the process of passive and active rehabilitation training. And the effects of the load parameters on the rehabilitation have been analyzed.