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The series elastic actuators make more comfort in the use of assistive exoskeletons. In this paper, an assistive controller is designed for a series-elastic-actuator-driven knee exoskeleton to restore normative mobility of individuals with weak muscles. The main target of the proposed controller is to modify the dynamics performance of the coupled humanexoskeleton system. In other words, the proposed controller modifies the relationship between the net muscle torque exerted by the human and the resulting angular motion. There are fewer sensors in the proposed intent-independent method relative to other methods. Moreover, there are less controller coefficients to regulate where these coefficients are extracted from a type zero Takagi-Sugeno-Kang fuzzy system. The performance of the controller is evaluated by simulations and experiments. The amplitude of the EMG signals decreased in a healthy person worn the SUT-KneeExo. Moreover, the proposed algorithm has a better performance in comparison with integral admittance shaping mothed and output feedback assistive controller. In other words, the amplitude of the integral admittance is more and the phase lag is less than other methods. [ABSTRACT FROM AUTHOR]

Modeling the movement of different parts of the body has been studied a lot in recent years. Body movement models such as fingers movements are good guides for designing different robots. Also, motion disability is one of the common diseases that have a great impact on patients' life quality. To treat the rupture of finger tendon, individual rehearsal rehabilitation exercises for each phalanx is required. In order to achieve this aim and take control of each phalanx movement, the mathematical model of the desired trajectory for each joint is necessary. The angle of each joint is measured with the help of a gyro sensor installed on a novel wearable rehabilitation robot proposed in this paper. The mathematical models of the phalanges motions are obtained by curve fitting. The model is applicable not only in the rehabilitation robots but also in the other robotic works. In most of the works in this area, the desired trajectory diagram was drawn and tracking of the trajectory was investigated. Thus, the desired trajectory formula should be fined for the other works. But in this work, the corresponding formula was found and it can help other researchers to easily use of these formulas for their work. To ensure the accuracy and efficiency of the calculated trajectories, the trajectories are implemented in a control system. In order to control this system, a suitable sliding mode controller was designed and the results of system controlling and trajectory tracking using this controller was obtained. [ABSTRACT FROM AUTHOR]

Background and aim: Physical activities in occupations like handling, static and dynamic postures, sudden movements, and repetitive postures are amongst most important risk factors of Work related Musculoskeletal Disorders (WMSDs). There are many ergonomic methods for assessing WMSDs which can be used in different cases, but these assessments and analyses can't be beneficial by themselves and should be promoted with usable, practical suggestions to improve the work condition. This quality is brought to this research paper by first assessing ergonomic risks level, resulted by postural stresses, with special emphasis on improper postures, forces and repeating and then using these information to design assisting device called exoskeleton for improving work condition and industrial tasks. Methods: For assessing and analyzing upper body work condition, postures in 17 different tasks were analyzed by RULA (Rapid upper limb assessment) method and a set of 60 worksheets were created out of them. Also biomechanical movement observation during normal tasks was done. Then HONDA company's exoskeleton for lower body was analyzed and some design elements were extracted from it, to design an upper body exoskeleton based on the same design language. Results: This Research shows that none of tasks were completely acceptable, and neck, trunk and legs were more affected by improper postures. There was no meaningful difference between right and left hand conditions in overall task and posture assessment. Research also shows dominant effect of force and repeat risk factors in tasks being harmful for upper body. Analyzing HONDA company's exoskeleton shows the likelihood of success in upper body exoskeleton for improving work conditions and minimizing WMSDs. Conclusion: Although redistribution or regular rotation of personnel, changing and optimizing work cycles and proper training might reduce WMSDs and improve work condition, but using an assisting device such as exoskeleton can minimize WMSDs and have a more desirable effect from ergonomic and physiological perspectives. Assisting devices like HONDA company's lower body assisting exoskeleton have clearly shown the statement to be true. [ABSTRACT FROM AUTHOR]