Development Of An Ankle Rehabilitation Robot Combined With The Healthy Side And The Affected Side

The ankle joint is located at the distal part of the human lower extremities and plays an important role in the movement of human body.With the trend of population aging,the movement dysfunction of the ankle caused by stroke hemiplegia is becoming more and more prominent.Besides,ankle injury is also a common phenomenon due to unexpected falls,strenuous sports and traffic accidents.Rehabilitation training of ankle joint is an important part of rehabilitation treatment after stroke hemiplegia and ankle joint injury,especially for the recovery of gait of patients with stroke in early stage of hemiplegia.Ankle rehabilitation training is usually based on manual training,the patients usually need the help of ankle rehabilitation device,or rely on the clinicians operating skill.The operation skill of the clinician is an effective means in the rehabilitation training of the ankle joint,but there are some shortcomings in current ankle rehabilitation devices,such as imperfect function,low participation of patients,and unable to reproduce clinicians' operation skills.Rehabilitation robot combines the rehabilitation medicine and the robot technology,it has become a research hotspot in the field of robotics in recent years and it has been has been widely applied in rehabilitation therapy.However,the existing ankle rehabilitation robot has many shortcomings such as the single training pattern,unreasonable mechanism design,lack of information feedback from patients and so on.Therefore,based on the new concept of "Combination of the Healthy Side and the Affected Side",and an ankle rehabilitation robot combined with the healthy side and the affected side is developed in this paper,which can simulate the operation skills of clinicians and improve the participation of ankle joint patients.The ankle rehabilitation robot combined with the healthy side and the affected side is designed by serial mechanism,so it is also called the new serial ankle rehabilitation robot.Its bilateral mechanism is symmetrical,and the motion of the ankle rehabilitation robot is highly consistent with the physiological movement of the ankle joint,that is,it has three rotational degrees of freedom,and the center of motion coincides with the physiological center of the ankle joint.The ankle rehabilitation robot also has rich sensors,which can monitor and control the speed,position and torque during ankle rehabilitation training.It can not only reproduce the operation skills of the clinicians,complete a variety of rehabilitation training patterns,but also record the information of movement and force during the rehabilitation training of ankle joint,and make it convenient for clinicians to quantify the situation of ankle joint patients.First,the important research achievement of ankle rehabilitation robots both at home and abroad are introduced,and the characteristics of various ankle rehabilitation robots are analyzed from the aspects of mechanism design and control system design.On the basis of summarizing the shortcomings of the existing ankle rehabilitation robots and the development trend of the ankle rehabilitation robot,the aim of this paper to develop an ankle rehabilitation robot combined with the healthy side and the affected side is put forward.Then,the design requirement analysis of ankle rehabilitation robot is carried out.The objective and parameters of the mechanism design and control system design of the ankle joint rehabilitation robot are clearly defined from two aspects: the physiological structure and movement of the ankle joint,the rehabilitation training of the ankle joint.Secondly,according to the design goal of the ankle rehabilitation robot mechanism,a new serial mechanism scheme is proposed,which divides the mechanism into three movable parts,the adduction/abduction parts,the dorsiflexion/plantar flexion parts and the inversion/eversion parts.After completing the design of the body structure,transmission system and the limiting structure of the new ankle rehabilitation robot,a virtual prototype of ankle rehabilitation robot was established in ADAMS software and the dynamics analysis of its motion parts is carried out.Thirdly,according to the design goal of the control system for ankle rehabilitation robot,the design of the control system for ankle joint rehabilitation robot is designed from the electrical system design,software system design and control strategy.Combined with ADAMS and MATLAB software,the co-simulation of the ankle rehabilitation robot is carried out.The electrical system design introduces the selection of electronic components,such as motor,driver and sensor,and combined with the body structure and the electrical system,the assembly of the physical prototype of the ankle rehabilitation robot is completed.The software system design introduces the application of driver and motion function library,the application of C++ Builder software and the control interface design of ankle rehabilitation robot.In the control strategy,it introduces the control strategy of the mechanism of the ankle rehabilitation robot,and the control strategy of three kinds of rehabilitation training patterns that is,the active training pattern,the passive training pattern and the training pattern combined the healthy side and the affected side.Finally,the basic control programs of the brushless DC servo motor,such as point motion control,position control and reciprocating motion control are completed,and then they are applied to various motion mechanisms of the ankle rehabilitation robot's physical prototype and are adjusted to obtain the optimal control parameters.In particular,a nonlinear PID position control algorithm is tested to improve the position control of the mechanism;the sinusoidal time function is introduced to the reciprocating motion control as the target trajectory to improve the operating condition of the mechanism.In order to monitor the torque of the mechanism in motion and implement torque control of the ankle rehabilitation robot,torque measurement experiments were carried out.In order to prove that the ankle rehabilitation robot combined with the healthy side and the affected side can achieve the desired function,a healthy individual is selected to carry out the passive training,active training and the training combined with the healthy side and the affected side of the ankle joint.