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...tures of this exoskeleton is that it is energetically autonomous, or carries its own power source. Indeed, its developers claim it as the first "load-bearing and energetically autonomous" exoskeleton =-=[17]-=-. BLEEX features three degrees of freedom (DOF) at the hip, one at the knee, and three at the ankle. Of these, four are actuated: hip flexion/extension, hip abduction/adduction, knee flexion/extension...

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...nt of locomotory function. A second example of a parallel-limb orthosis that augments joint torque and work is shown in Figure 3b. The MIT Biomechatronics Group developed a powered anklefoot orthosis =-=[52]-=- to assist drop-foot gait, a deficit affecting many persons who have experienced a stroke, or with multiple sclerosis or cerebral palsy, among others. The device consists of a modified passive ankle-f...

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... (monoarticular vs. polyarticular actuation) and be controlled to produce enhanced biomimetic limb dynamics. For example, neuromechanical models that capture the major features of human walking (e.g. =-=[63,64]-=-) may improve understanding of musculoskeletal morphology and neural control and lead to analogous improvements in the design of economical, stable and low-mass exoskeletons for human walking augmenta...

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...At the University of Tsukuba in Japan, Professor Yoshiyuki Sankai and his team have been developing an exoskeleton concept that is targeted for both performance-augmenting and rehabilitative purposes =-=[49,50]-=-. The leg structure of the full-body HAL-5 exoskeleton powers the flexion/Page 4 of 9 (page number not for citation purposes) ever, was approximately twice that of their hydraulicallyactuated joint (4...

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...s of critical importance to the field of wearable devices. Electroactive polymers have shown considerable promise as artificial muscles, but technical challenges still remain for their implementation =-=[61,62]-=-. These challenges include improving the actuator's durability and lifetime at high levels of performance, scaling up the actuator size to meet the force and stroke needs of exoskeletal/ orthotic devi...

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... speeds of up to 1.3 m/s without the load. A second generation of the Berkeley exoskeleton is currently in testing. The new device is approximately half the weight of the original exoskeleton (~14 kg =-=[22]-=-), in part due to the implementation of electric actuation with a hydraulic transmission system. A laboratory spin-off company called Berkeley Bionics (Berkeley, CA) has been formed in order to market...

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...At the University of Tsukuba in Japan, Professor Yoshiyuki Sankai and his team have been developing an exoskeleton concept that is targeted for both performance-augmenting and rehabilitative purposes =-=[49,50]-=-. The leg structure of the full-body HAL-5 exoskeleton powers the flexion/Page 4 of 9 (page number not for citation purposes) ever, was approximately twice that of their hydraulicallyactuated joint (4...

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...[18]. In order to achieve their goal of being energetically autonomous with such an actuator selection, significant effort was invested in developing a hybrid hydraulic-electric portable power supply =-=[21]-=-. In terms of performance, users wearing BLEEX can reportedly support a load of up to 75 kg while walking at 0.9 m/ s, and can walk at speeds of up to 1.3 m/s without the load. A second generation of ...

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... Group recently built an elastic exoskeleton similar to Yagn's design. However, its intended application was not for running augmentation, but for lowering the metabolic demands of continuous hopping =-=[15,16]-=-. The exoskeleton, shown in Figure 2b, comprises fiberglass leaf springs that span the entire leg, and is capable of transferring body weight directly to the ground during the stance period. In distin...

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...ent and may also reduce the risk of injury [8]. In another study on elastic running surfaces, the authors found a range of compliant ground surface stiffnesses that improved metabolic running economy =-=[9]-=-. Similarly, previous studies have shown that wearable mechanisms in series with the biological leg can reduce the metabolic cost of running by lowering impact losses and by providing energy return. A...

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...have the potential to be used for sensory feedback to the nerves or brain, thus allowing the exoskeletal wearer to have some form of kinetic and kinematic sensory information from the wearable device =-=[67]-=-. Current exoskeletal/orthotic devices are also limited by their mechanical interface. Today's interface designs often cause discomfort to the wearer, limiting the length of time that a device can be ...

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...ons would augment human running speed and economy. Notable inventions in this exoskeletal class are the PowerSkip and the SpringWalker shown in Figure 1b and 1c, respectively http://www.powerskip.de; =-=[12]-=-. However, although these devices clearly augment jumping height, they have not been shown to improve peak running speed nor running economy. In fact, in a study conducted by the U.S. Army Research In...

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... (monoarticular vs. polyarticular actuation) and be controlled to produce enhanced biomimetic limb dynamics. For example, neuromechanical models that capture the major features of human walking (e.g. =-=[63,64]-=-) may improve understanding of musculoskeletal morphology and neural control and lead to analogous improvements in the design of economical, stable and low-mass exoskeletons for human walking augmenta...

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... power to actuator weight)" [18]. However, a further study determined that electric motor actuation significantly decreased power consumption during level walking in comparison to hydraulic actuation =-=[20]-=-. The weight of the implementation of the electrically-actuated joint, howThe control scheme of the BLEEX seeks to minimize the use of sensory information from the human/exoskeleton interaction, and i...

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...heral sensors placed inside muscle to measure the electromyographic signal, or centrally-placed sensors into the motor cortex, may be used to assess motor intent by future exoskeletal control systems =-=[65,66]-=-. Neural implants may have the potential to be used for sensory feedback to the nerves or brain, thus allowing the exoskeletal wearer to have some form of kinetic and kinematic sensory information fro...

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...tons that act in parallel with the human lower limb for load transfer to the ground. Examples are Yagn'ssrunning aid [14], MIT's hopping exoskeleton [15,16], and Kazerooni's load-carrying exoskeleton =-=[18,19]-=- shown in 2a, 2b, and Page 3 of 9 (page number not for citation purposes) 2c, respectively. Journal of NeuroEngineering and Rehabilitation 2009, 6:21 http://www.jneuroengrehab.com/content/6/1/21 Paral...

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...tons that act in parallel with human joint(s)sfor torque and work augmentation. Examples are the Page 5 of 9 (page number not for citation purposes) amplify endurance using this strategy, researchers =-=[59]-=- conducted an experiment on six human subjects each HAL 5 exoskeleton [49,50] and the MIT active ankle-footsorthosis [52] shown in 3a and 3b, respectively. Journal of NeuroEngineering and Rehabilitati...

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... such as shoes and exoskeletons. Previous studies have shown that a compliant running track can improve performance by increasing running speed by a few percent and may also reduce the risk of injury =-=[8]-=-. In another study on elastic running surfaces, the authors found a range of compliant ground surface stiffnesses that improved metabolic running economy [9]. Similarly, previous studies have shown th...

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...applications for this class of exoskeleton. For example, a crutch was constructed with an orthotic elbow spring to maximize the endurance of physicallychallenged persons in climbing stairs and slopes =-=[60]-=-. When the crutch user flexes both elbows to place the crutch tips onto the next stair tread, orthotic elbow springs compress and store energy. This stored energy then assists the crutch user during e...

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...return. A running shoe called the Springbuck, designed with a carbon composite elastic midsole, was shown to improve shock absorption and metabolic economy at moderate running speeds (see Figure 1a); =-=[10,11]-=-. Although metabolic economy improved when runners used this elastic shoe rather than a conventional shoe design without an elastic midsole, the advantage was found to be modest (~2%). Elastic exoskel...

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... Group recently built an elastic exoskeleton similar to Yagn's design. However, its intended application was not for running augmentation, but for lowering the metabolic demands of continuous hopping =-=[15,16]-=-. The exoskeleton, shown in Figure 2b, comprises fiberglass leaf springs that span the entire leg, and is capable of transferring body weight directly to the ground during the stance period. In distin...

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...s of critical importance to the field of wearable devices. Electroactive polymers have shown considerable promise as artificial muscles, but technical challenges still remain for their implementation =-=[61,62]-=-. These challenges include improving the actuator's durability and lifetime at high levels of performance, scaling up the actuator size to meet the force and stroke needs of exoskeletal/ orthotic devi...

Citation Context

...heral sensors placed inside muscle to measure the electromyographic signal, or centrally-placed sensors into the motor cortex, may be used to assess motor intent by future exoskeletal control systems =-=[65,66]-=-. Neural implants may have the potential to be used for sensory feedback to the nerves or brain, thus allowing the exoskeletal wearer to have some form of kinetic and kinematic sensory information fro...