In this study, an energy-efficient gait pattern and swing trajectory of the powered robotic exoskeleton was proposed through function distribution analysis and the dynamic-manipulability ellipsoid (DME). The exoskeleton has 3 DOF at each side, and it is possible to determine the minimum energy consumption of the joint torques under level-ground walking and stair ambulation conditions. To verify its feasibility and the effect of the proposed optimal gait pattern from the point view of the integrated system (human and exoskeleton), simulations were performed in the cases of walking on level ground and stair ascent/descent. Experiments such as on the metabolic cost of the human body with or without the assistance of the exoskeleton were conducted, and the power consumption of the exoskeleton was assessed, with the aim of improving the efficiency of the integrated system.

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We aim to develop the Hybrid Assistive Lims (HAL) in order to enhance and upgrade the human capabilities based on the frontier science Cybernics. Cybernics is a new domain of interdisciplinary research centered on cybernetics, mechatronics, and informatics, and integrates neuroscience, robotics, systems engineering, information technology, “kansei” engineering, ergonomics, physiology, social science, law, ethics, management, economics etc. Robot Suit HAL is a cyborg type robot that can expand, augment and support physical capability. The robot suit HAL has two types of control systems such as “Cybernic Voluntary Control System” and “Cybernic Autonomous Control System”. The application fields of HAL are medical welfare, heavy work support and entertainment etc. In this paper, the outline of HAL and some of the important algorithms and recent challenges are described.

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A new and alternative method to measure the interaction force between the user and a lower-limb gait rehabilitation exoskeleton is presented. Instead of using a load cell to measure the resulting interaction force, we propose a distributed measure of the normal interaction pressure over the whole contact area between the user and the machine. To obtain this measurement, a soft silicone tactile sensor is inserted between the limb and commonly used connection cuffs. The advantage of this approach is that it allows for a distributed measure of the interaction pressure, which could be useful for rehabilitation therapy assessment purposes, or for control. Moreover, the proposed solution does not change the comfort of the interaction; can be applied to connection cuffs of different shapes and sizes; and can be manufactured at a low cost. Preliminary results during gait assistance tasks show that this approach can precisely detect changes in the pressure distribution during a gait cycle.

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(EN)This invention relates to a servo system for operating an exoskeleton adapted to encircle an object of interest and for supplying a force thereon. A servomotor is coupled to a power source and operates the position of the exoskeleton and thus the force exerted by the exoskeleton on the object of interest. A measuring unit measures a raw driving current signal I raw suplied by the power source to drive the servomotor. A low pass filter applies a low pass frequency filtering on the measured a filtered current signal I filtered. A processing unit determines an actuated current signal I actuated based on the servomotor setting parameters, where I actuated indicates the contribution to I raw from the servomotor when operating the position of the exoskeleton. The processing unit also determines a driving force current signal I force indication the force exerted by the exoskeleton on the object of interest, where I force is proportional to the difference between I filtered and I actuated.
(FR)La présente invention concerne un servosystème pour utiliser un exosquelette adapté pour encercler un objet d’intérêt et exercer une force dessus. Un servomoteur est couplé à une source d’énergie et modifie de la position de l’exosquelette, et ainsi de la force exercée par l’exosquelette sur l’objet d’intérêt. Une unité de mesure mesure un signal de courant d’excitation brut Iraw envoyé par la source d’énergie pour commander le servomoteur. Un filtre passe-bas applique un filtrage passe-bas de fréquence sur le signal de courant filtré mesuré l’filtered. Une unité de traitement détermine un signal de courant actionné l’actuated basé sur les paramètres de réglage du servomoteur, l’actuated indiquant la contribution à l’raw à partir du servomoteur lors de la modification de la position de l’exosquelette. L’unité de traitement détermine également un signal de courant de force motrice l’force indiquant la force exercée par l’exosquelette sur l’objet d’intérêt, l’force étant proportionnel à la différence entre l’iltered et l’actuated.

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To enable compliant training modes with a rehabilitation robot, an important prerequisite is that any undesired human-robot interaction forces caused by robot dynamics must be avoided, either by an appropriate mechanical design or by compensating control strategies. Our recently proposed control scheme of “Generalized Elasticities” employs potential fields to compensate for robot dynamics, including inertia, beyond what can be done using closed-loop force control. In this paper, we give a simple mechanical equivalent using the example of the gait rehabilitation robot Lokomat. The robot consists of an exoskeleton that is attached to a frame around the patient’s pelvis. This frame is suspended by a springloaded parallelogram structure. The mechanism allows vertical displacement while providing almost constant robot gravity compensation. However, inertia of the device when the patient’s pelvis moves up and down remains a source of large interaction forces, which are reflected in increased ground reaction forces. Here, we investigate an alternative suspension: To hide not only gravity, but also robot inertia during vertical pelvis motion, we suspend the robot frame by a stiff linear spring that allows the robot to oscillate vertically at an eigenfrequency close to the natural gait frequency. This mechanism reduces human-robot interaction forces, which is demonstrated in pilot experimental results.

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