A robotic ankle-foot orthosis (AFO) that provides powered assistance could adjust to varying gait dynamics much better than a rigid AFO. To provide insight into how humans would adapt to a powered AFO, we studied the response of neurologically intact subjects walking with an active dorsiflexion assist orthosis proportionally controlled by tibialis anterior electromyography (EMG). We examined the two mechanical functions of ankle dorsiflexors in gait (power absorption at heel strike and power generation at toe-off) by recruiting two groups of healthy subjects: Group One, called Continuous Control (n = 5), had dorsiflexion assistance both at the initial heel contact and during swing; Group Two, called Swing Control (n = 5), had the assistance only during swing. We hypothesized both groups of subjects would reduce tibialis anterior EMG amplitude with practice walking with the powered dorsi-flexion assist. Ten healthy subjects were fitted with custom-made orthoses that included an artificial pneumatic muscle providing dorsiflexor torque. We collected lower body kinematics, EMG, and artificial muscle force while subjects walked on a treadmill for two 30-min training sessions. We found that subjects walked with increased ankle dorsiflexion by 98 but showed different adaptation responses of the two tibi-alis anterior EMG bursts. The first EMG burst around heel strike had 28% lower amplitudes (p < 0.05) but the second EMG burst during swing had similar amplitudes. These results provide baseline data of EMG controlled dorsiflexion assist in neurologically intact humans that can be used to guide future studies on neurologically impaired individuals. (далее…)

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If a teleoperation scenario foresees complex and fine manipulation tasks a multi-fingered telemanipulation system is required. In this paper a multi-fingered telemanipulation system is presented, whereby the human hand controls a three-finger robotic gripper and force feedback is provided by using an exoskeleton. Since the human hand and robotic grippers have different kinematic structures, appropriate mappings for forces and positions are applied. A point-to-point position mapping algorithm as well as a simple force mapping algorithm are presented and evaluated in a real experimental setup.

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The ankle plantar flexor muscles, gastrocnemius (Gas) and soleus (Sol), have been shown to play important roles in providing body support and forward propulsion during human walking. However, there has been disagreement about the relative contributions of Gas and Sol to these functional tasks. In this study, using independent manipulations of body weight and body mass, we examined the relative contribution of the individual plantar flexors to support and propulsion. We hypo-thesized that Gas and Sol contribute to body support, whereas Sol is the primary contributor to forward trunk propulsion. We tested this hypothesis by measuring muscle activity while experimentally manipulating body weight and mass by 1) decreasing body weight using a weight support system, 2) increasing body mass alone using a combination of equal added trunk load and weight support, and 3) increasing trunk loads (increasing body weight and mass). The rationale for this study was that muscles that provide body support would be sensitive to changes in body weight, whereas muscles that provide forward propulsion would be sensitive to changes in body mass. Gas activity increased with added loads and decreased with weight support but showed only a small increase relative to control trials when mass alone was increased. Sol activity showed a similar increase with added loads and with added mass alone and decreased in early stance with weight support. Therefore, we accepted the hypothesis that Sol and Gas contribute to body support, whereas Sol is the primary contributor to forward trunk propulsion.

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Portable devices and methods for preventing deep vein thrombosis (DVT) by assuring that the ankle is flexed and extended sufficiently to promote blood flow in the lower leg are disclosed. The device includes an actuator with a free movement mode that allows a patient to move freely between activations or to initiate movement to delay a next automatic activation.

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An exoskeleton interface apparatus includes five rigid links (2-6) arranged in series, capable of rotating reciprocally at the respective ends for monitoring angular movements of the arm, of the forearm and the wrist of an user (60) and having at the tip an handgrip (30) for engaging with the user (60) by reflecting a force feedback. The rigid links (2-6) can rotate at their ends about rotational joints (11-14) having rotational axes (31-34) incident in the intersection point of the physiological axes of the shoulder. The rotational joints (11-14) are brought into rotation about the respective rotational axes (31-34) by means of respective motors (21-24), for example servo-motor such as torque motors. All the motors (21-24) are mounted on the fixed base link (2) in order to minimize the mass of the parts in movement and the inertia reflected on the user (60). A plurality of idle pulleys (50) is provided, spatially arranged for orienting the tendons (41-44), which brake the free movement of the relative rotational joint, responsive to signals corresponding to constraints on the slave in case of teleoperation or to constraints created by virtual reality systems.

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