Development Of Virtual Reality Control System Of Passive Upper Limb Rehabilitation Robot

Research shows that the timely and effective rehabilitation training can effectively promote the rehabilitation of patients with hemiplegic upper limb disorder. Rehabilitation robot based on virtual reality technology is the forefront of the application of virtual reality technology and robot technology in the field of rehabilitation, not only to help the patients with rehabilitation training and collect the training parameters, but also the virtual scene established by the virtual reality technology can encourage patients to participate in the rehabilitation training more actively.In order to help the hemiplegic upper limb disorder patients to achieve complete rehabilitation, the research group developed a passive three degrees of freedom of upper limb rehabilitation robot system based on virtual reality technology. Now, the current prototype of the rehabilitation robot and kinematics analysis has been completed. On the basis of participation of the whole project, the author is mainly responsible for establishing virtual reality interactive platform and the development of the whole control system.Virtual scene established by virtual reality technology for rehabilitation therapy involves three key links including repetition, feedback and motivation, and it is more in line with the application demand of clinical rehabilitation that it can help patients to achieve more safe, effective and durable rehabilitation exercise training. The virtual scene used for rehabilitation training in this paper is created by using Windows GDI and OpenGL (Open Graphics Library) based on VC++ development environment. The establishment of virtual scene should not only be in conformity with the actual movements of the rehabilitation robot, but also the resistance exercise mode is set in the scene which can be adapted to different strength rehabilitation training of patients through the force feedback effect. The virtual scene can greatly improve the interest in rehabilitation training of patients.In order to realize the reliable interaction between patients, rehabilitation robot and virtual scene, this article has carried on the development of the whole control system, including two aspects: firstly, the multi-threaded serial communication technology is used to realize the real time data acquisition and processing of three rotation axis of the rehabilitation robot that it completes the interaction between the rehabilitation robot and virtual scene. Secondly, digital signal processor 2407A is used to establish the lower machine control system. Adjustable duty ratio of pulse width modulation (PWM) signal can easily drive the magnetic powder brake which is produced by 2407A. At the same time, considering the PWM signal is not sufficient to control the cause of the power tube, the driver amplifier circuit is established by using IR2125. The signal and the circuit overall realized the forecast function that the size of the output torque of magnetic powder brake is adjusted conveniently which meets the requirements of different intensity of rehabilitation training. The successful implementation of the overall system has laid a solid foundation for other work in the future such as the increase of recovery pattern, the establishment of the evaluation system et al.