Joints are failure points for deployable systems and moving devices. Their reliability is therefore of great concern for space applications. Efficiency is also critical as the power budgets are limited in space and energy dissipation must therefore be avoided. Weight and dimensions must be reduced as much as possible since they have a direct impact on launch costs and thus on space mission budgets. A new type of joint design that meets the extensive and demanding space requirements would be of great use. This study tries to retrieve interesting mechanisms in the huge pool of clever designs from nature. The number of species of insects is truly awesome, for example there are over 600,000 scientifically described species of beetles with at least twice that number remaining to be disco-vered and described. And beetles are only one type of insect. To put that number in perspective, there are probably around 10,000 species of birds, and maybe 4,000 species of mammals. The total number of interes-ting mechanisms in insect species, birds and mammals is almost beyond imagination. In this work a biomime-tic approach is used in order to assess the possibility of improving robotic joints for space applica-tions. The work concerns the identification of classes of joints in nature which could inspire the design of a feasible system in which the mechanical subsystem and the actuation subsystems are merged. This report presents a study with the overall goal of finding biological articulation concepts which, when tran-slated to a mechanical equivalent, can improve performance of articulated robot systems for space applications.

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Metabolic studies have shown that there is a metabolic cost associated with carrying load [1]. In previous work, a lightweight, underactuated exoskeleton has been described that runs in parallel to the human and supports the weight of a payload [2]. A state-machine control strategy is written based on joint angle and ground-exoskeleton force sensing to control the joint actuation at this exoskeleton hip and knee. The joint components of the exoskeleton in the sagittal plane consist of a force-controllable actuator at the hip, a variable-damper mechanism at the knee and a passive spring at the ankle. The control is motivated by examining human walking data. Positive, non-conservative power is added at the hip during the walking cycle to help propel the mass of the human and payload forward. At the knee, the damper mechanism is turned on at heel strike as the exoskeleton leg is loaded and turned off during terminal stance to allow knee flexion. The passive spring at the ankle engages in controlled dorsiflexion to store energy that is later released to assist in powered plantarflexion. Preliminary stu- dies show that the state machines for the hip and knee work robustly and that the onset of walking can be detected in less than one gait cycle. Further, it is found that an efficient, underactuated leg exoske-leton can effectively transmit payload forces to the ground during the walking cycle.

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Various embodiments of an ambulation and movement assist system are disclosed. For example, an ambulation system for a patient may comprise an exoskeleton device attached to the patient, an FES device at least partially implanted in the patient, and a biological interface apparatus. The biological interface apparatus comprises a sensor having a plurality of electrodes for detecting multicellular signals, a processing unit configured to receive the multicellular signals from the sensor, process the multicellular signals to produce a processed signal, and transmit the processed signal to a controlled device. At least one of the exoskeleton device and the FES device is the controlled device of the biological interface apparatus.

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This research aims to develop a portable haptic master hand with 20 degrees of freedom (DOF). Master hands are used as haptic interfaces in master-slave systems. A master-slave system consists of a haptic interface that communicates with a virtual world or an end-effector for tele-operation, such as a robot hand. The thumb and fingers are usually modeled as a serial linkage mecha-nism with 4 DOF. So far, no 20 DOF master hands have been developed that can exert perpendicular forces on the finger phalanges during the complete flexion and extension motion. In this paper, the design and development of two concepts of a portable 4 DOF haptic interface for the index finger is presented. Concept A is a statically balanced haptic interface with a rolling-link mechanism (RLM) and an integrated constant torque spring per DOF for perpendicular and active force feedback. Concept B utilizes a mechanical tape brake at the RLM for passive force feedback. The systematic Pahl and Beitz design approach is used as an iterative design method.

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Robot-mediated neurorehabilitation is a rapidly advancing field that seeks to use advances in robotics, virtual realities, and haptic interfaces, coupled with theories in neuroscience and rehabilitation to define new methods for treating neurological injuries such as stroke, spinal cord injury, and traumatic brain injury. The field is nascent and much work is needed to identify efficient hardware, software, and control system designs alongside the most effective methods for delivering treatment in home and hospital settings. This paper identifies the need for robots in neurorehabilitation and identifies important goals that will allow this field to advance.

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