A pace recognition method for exoskeleton wearers based on support vector machine-hidden Markov model / 生物医学工程学杂志

In order to improve the motion fluency and coordination of lower extremity exoskeleton robots and wearers, a pace recognition method of exoskeleton wearer is proposed base on inertial sensors. Firstly, the triaxial acceleration and triaxial angular velocity signals at the thigh and calf were collected by inertial sensors. Then the signal segment of 0.5 seconds before the current time was extracted by the time window method. And the Fourier transform coefficients in the frequency domain signal were used as eigenvalues. Then the support vector machine (SVM) and hidden Markov model (HMM) were combined as a classification model, which was trained and tested for pace recognition. Finally, the pace change rule and the human-machine interaction force were combined in this model and the current pace was predicted by the model. The experimental results showed that the pace intention of the lower extremity exoskeleton wearer could be effectively identified by the method proposed in this article. And the recognition rate of the seven pace patterns could reach 92.14%. It provides a new way for the smooth control of the exoskeleton.

Comfort optimization of a new type of foot mechanism for lower extremity exoskeleton / 生物医学工程学杂志

In order to reduce the impact caused by the contact between the foot and the ground when wearing the lower extremity exoskeleton under the condition of high load, this paper proposed an exoskeleton foot mechanism for improving the foot comfort, and optimized the key index of its influence on the comfort. Firstly, the physical model of foot mechanism was established based on the characteristics of foot stress in gait period, and then the mathematical model of vibration was abstracted. The correctness of the model was verified by the finite element analysis software ANSYS. Then, this paper analyzed the influence of vibration parameters on absolute transmissibility based on vibration mathematical model, and optimized vibration parameters with MATLAB genetic algorithm toolbox. Finally, this paper took white noise to simulate the road elevation as the vibration input, and used the visual simulation tool Simulink in MATLAB and the vibration equation to construct the acceleration simulation model, and then calculated the vibration weighted root mean square acceleration value of the foot. The results of this study show that this foot comfort mechanism can meet the comfort indexes of vibration absorption and plantar pressure, and this paper provides a relatively complete method for the design of exoskeleton foot mechanism, which has reference significance for the design of other exoskeleton foot and ankle joint rehabilitation mechanism.

Research of a Wearable Lower Extremity Assisted Exoskeleton Robot System / 中国康复理论与实践

Objective:To propose a new type of lightweight wearable lower extremity exoskeleton assisted robot system, and explore the feasibility of walking and posture change rehabilitation training for patients with gait disorder and with paraplegia under T4 spinal cord injury (exclusion of lower extremity muscle spasm and obvious pain). Methods:The active and passive hybrid wearable lower extremity exoskeleton assisted robot structure of the hip joint with two-motor active drive and the knee joint passive four-link simulating the instantaneous movement of the human body was designed. Based on modular control, the STM32F767IGT6 and peripheral circuits, attitude acquisition, power supply and crutches module control system were proposed. The exoskeleton robot was worn by a normal person to perform the experiment of leveling, slope and posture transformation and analyze hip/knee /ankle joint angles during exercise, and compare the myoelectric signals of the lateral femoral and medial femoral muscles. Results:The wearer could realize the sitting-standing posture change and the flat/slope walking only based on the exoskeleton robot system, and the hip/knee/ankle angles were basically consistent with the normal walking and the electromyographic signals of the lateral femoral, medial femoral muscle significantly decreased when the robot was worn while walking. Conclusion:The active-passive hybrid lower exoskeleton assisted robot system can still achieve the rehabilitation of walking and posture change while reducing the weight. This verified the feasibility of the assisted robot system with the active dual-motor of the hip joint and the passive four-link structure of the knee joint to help the patients with paraplegia and gait disorder to walk and recover.

Research progress on compliant characteristics of lower extremity exoskeleton robots / 生物医学工程学杂志

The lower extremity exoskeleton robot is a wearable device designed to help people suffering from a walking disorder to regain the power of the legs and joints to achieve standing and walking functions. Compared with traditional robots that include rigid mechanisms, lower extremity exoskeleton robots with compliant characteristics can store and release energy in passive elastic elements while minimizing the reaction force due to impact, so it can improve the safety of human-robot interaction. This paper reviews the compliant characteristics of lower extremity exoskeleton robots from the aspects of compliant drive and compliant joint, and introduces the augmentation, assistive, rehabilitation lower extremity exoskeleton robots. It also prospect the future development trend of lower extremity exoskeleton robots.

Design and Application of Active Lower Extremity Exoskeleton System: Appliance to Improve Walking Function (review) / 中国康复理论与实践

@# Lower extremity exoskeleton system is a kind of human-machine robot, which combines the artificial intelligence with the power of mechanism. Recent years, the field of lower extremity exoskeleton robots have rapidly evolved and development of relevant technologies have dramatically increased these robots available for facilitating human walking function that could only be imagined a few years ago. Some technologies are so new that they lack the scientific evidence that would justify their use in the real setting. This paper presents an over view of design configurations, control methods and simulation test used for lower extremity exoskeleton robots. Further research efforts are required in order to incorporate many of the new technologies described in this review to promote the development of the lower extremity exoskeleton robots.