Development and Evaluation of a Postural Controlled Exoskeleton Robotic Orthosis and Software Protocol for Load Redistribution, Proprioception Training and Motor Control Enhancement for Knee Joint

The patients with knee osteoarthritis have some symptoms: pain, joint stiffness, range of motion decreasing, lower limb muscle weakness and have slower walking speed. These symptoms would affect the patients’ gait pattern and the ability for executing functional activities. Costigan reported the load of knee joint during stair climbing was 3-6 times than level walking, makes the patients more painful when climbing stairs. The patients with knee osteoarthritis have impair proprioception because of muscle weakness, poor coordination, impair mechanical receptors makes the patients couldn＇t rise their leg appropriately. In this study, a postural controlled robotic exoskeleton orthosis and software protocol for load redistribution, proprioception training and motor control enhancement for knee joint will be developed. In this two-year research project, the main task for the first part (first year) is to develop the proposed robotic exoskeleton orthosis. SolidWorks CAD tool will be used to design the exoskeleton structure which composed of a pneumatic cylinder, an air reservoir and a relief valve. When patients flex their knee joint, the piston in air cylinder will be compressed and the air in the system and it will flow into the air reservoir. When the limit switch is triggered, the relief valve will be closed and the air will store in the air reservoir. Besides, an insole integrated with flexiforce sensor will be developed. The insole can measure foot pressure when climbing stairs. The relief valve will be controlled by foot pressure signals and threshold on wearing the lower limb orthosis to climb stairs. The relief valve will be opened and the air stored in the air reservoir will be released to offer assisted power. It will resist the weight support to reduce the knee joint load. The control unit of the proposed robotic exoskeleton orthosis consist of AT89S52 MCU module, ADC module, relay control module, real-time system status display module, power supply regulator module and RS232 asynchronous serial transmission module. In the second part (second year), the motor control enhancement and proprioception training software will be developed and use for clinical evaluation. The proposed training software will be designed by using MATLAB. The human interface module consists of user data management module and visual feedback interactive training module. Subjects’ name, sex, age, affected side and knee joint ROM will be recorded by the user data management module. The testing protocol will be designed to ask subject to flex and hold their knee joint at the target position. In addition, the experimental protocol for evaluating knee joint load redistribution and proprioception training effect will be studied. Normal subjects will be recruited to perform climbing stairs and squatting tasks. EMG of rectus femoris, vastus lateralis and vastus medialis will be measured to evaluate the muscle activity and foot pressure will be measured by force platform to examine the weight bearing ability. Upon completing of this research project, a postural controlled robotic exoskeleton orthosis and software protocol for load redistribution, proprioception training and motor control enhancement for knee joint will be developed. This proposed system may provide knee OA patient a new clinical tool for decreasing the knee joint loading when climbing stairs and squatting.

Project ID:PB10007-2298
External Project ID:NSC100-2221-E182-067