Research On The Manipulator System For Functional Rehabilitation Of Finger Injuries

As an application of robotics in medical field, rehabilitation robots spur the development of rehabilitation theory and the advancement of the clinic-rehabilitation technology. Rehabilitation robotics has become one of the most promising researches in robot field. As one branch of rehabilitation robots, the main task of manipulator system for functional rehabilitation of finger injuries is assisting patient with hand injury do rehabilitation exercise after surgical operation. Based on the theory of Evidence Based Medicine and Continuous Passive Motion, it can make the patient get well in the shortest possible time. In order to provide a hand rehabilitation machine to the patients, an apparatus to doctors for clinical study, to improve the level of automation and intelligence in hand function rehabilitation, based on the scientific and technological key project in Heilongjiang province"Research on the intelligent motivated clinical bionic manipulator for the function rehabilitation of injured hands (fingers)", the manipulator for functional rehabilitation of finger injuries is developed. The work is aimed to solve the key problems during the development of the system such as: rehabilitation principle, mechanical and electrical system design, measurement system design, kinematics and dynamics analysis, position control algorithm, rehabilitation mode and system implementation.On demand of the clinical rehabilitation, we make the rehabilitation treatment planning. Based on the biological characteristic analysis of human hand, a manipulator system is developed for the rehabilitation of injured fingers after operation. The manipulator which is on the side of human hand can simulate natural trace of finger motion through linkage coupling mechanism, and then drive one or more fingers do flexion/extension exercises. It can also provide for a force that is applied perpendicular to the bone of the finger under therapy during the rehabilitation. This, in turn, causes minimum tissue irritation of the soft tissue surrounding the bone of the finger. The relative motion of couple linkages is realized through gear mechanisms, which can reduce DOF and complexity of finger system. Adopting the idea of mechatronics integration, we take into account disposition of all mechanical part, driver, sensors, electrical part and control part. The lower control module based on FPGA not only realizes motor drive, but also realizes all sensors and encoder information acquisition and transmission. The real-time computing module based on DSP realizes high intensity computation task. The human-machine interaction module on which running Linux operating system based on ARM, can realize multiprocessing and human-machine interaction function. The distributing control strategies of manipulator satisfy real time control and the requirements of rehabilitation. The measurement system of rehabilitation manipulator is designed based on exoskeleton sliding bar mechanism. Joint position sensor and fingertip force sensor are integrated into the mechanism, which can real-time feedback angle and force information of finger joint. To deal with the problem of velocity signal picked up by position difference method which has high noise, state parameters of the system is estimated by extension state observer. Adjustable parameters of extension state observer are optimized by the improved particle swarm optimizer. The systematic dynamical performance is improved by the differential signals, which can serve as a feedback on joint velocity.Based on the robotics theory, the mathematical models of human hand and rehabilitation manipulator have been built. Kinematics and statics analysis of human finger as well as kinematics and dynamics analysis of rehabilitation manipulator have been done, which lay foundation for analysis of injured finger damping parameters and movement control of rehabilitation manipulator.Based on the status feedback signal extracted by extension state observer, a new two-loop controller consist of disturbance observer and sliding mode variable structure controller is designed for compensating effect of disturbance and improving movement stability of manipulator. In the inner-loop, disturbance observer is designed to compensate effect of disturbance by generating a correcting signal; in the outer-loop, sliding mode controller based on adaptive control law is designed to make the system meet the performance requirement. Applied two-loop control strategy on the basis of close loop adjustment, the system can minimize bad effects of disturbance and system parameter variation, and can improve robust performance for the position control.Finally, flexion rehabilitation experiments of the manipulator system for functional rehabilitation of finger injuries are done. The experiments include hand fitness experiment, position control experiment, continuous passive motion experiment, and finger joint's damping parameters measuring experiment. The results demonstrate that the rehabilitation manipulator system works reliable, the rehabilitation principle and method are correct, and the rehabilitation manipulator system can satisfy the rehabilitation requirements of the injured fingers.