Research On The Control System Of The Human Lower Limb Exoskeleton

With the society aging and the increase of various security incidents, the number of elderly or disabled people who have difficulty with the lower limb movement has increased. Medical theory and clinical experience certificate that physical rehabilitation exercise training must be carried out to prevent muscle atrophy and recover muscle performance. Practically, patients could hardly take physical rehabilitation training independently, without nurses or other personnel help due to the functional obstacles, taking a lot of time and resources. Furthermore,crews like soldiers, rescue workers and firefighters are also supposed to complete very difficult physical exercise in hazardous environments. To alleviate these problems, scientist developed new kind of Wearable robot to help the human rehabilitation training and other difficult tasks.Not only did they help the sick or elderly people to complete a variety of scientific rehabilitation training, but also help carry heavy loads to the destination, saving energy and time, and avoiding injury. Although the existing exoskeleton robot performance meets the requirements, but in the overall design, cost, processing and portability still faces many problems, which severely restricts the application of the exoskeleton robot. In this paper, in associated with the existing external skeletal technology, a new type of human lower limb wearable robot is designed to overcome the existing problems and obtain more widespread application.In this paper, primarily, the mechanism of the lower limb exoskeleton is designed. Then,the mechanical mechanism of the lower limb of the human body is designed based on the analysis of the currently exoskeleton design level. According to the gait information and gait characteristics of human movement the kinematic characteristics of the lower limb wearable robot a suitable control scheme is designed.Secondly, design and implement of the robot control system. Appropriate human gait information detection sensors, including pressure sensor, contact force sensor, angular displacement sensors of each joint, and accelerometer are selected, signal acquisition and processing system are designed; select the joint motion drive element. Apply appropriate motion control algorithm in allusion to the control characteristics of the external skeleton, to complete the controller design.Third, In order to give the exoskeleton wider application area, this paper combines rehabilitation and energizing modes of exoskeleton system. Together with the PC software to switch the operating mode, acquire sensor data and display information on screen, so that it is convenient to record the working status, data changes, specific analysis and processing of the entire system.In addition, the gait prediction methods and control methods are studied and implemented.With the application of information fusion technology,the multi sensor information of the wearable robot for lower limb is fused and processed. Besides, the intelligent Fuzzy adaptive PID algorithm are used to improve the control performance of the system.Finally, some experiments about whole system was fulfilled, hardware and software of the system are independently tested, carrying out the gait detection information to verify the rationality of the system design. Ultimately, the results of the experiments prove that this exoskeleton system is sufficient to complete rehabilitation,walk, squat and other movements.