The structural design, control system, and integrated biofeedback for a wearable exoskeletal robot for upper extremity stroke rehabilitation are presented. Assisted with clinical evaluation, designers, engineers, and scientists have built a device for robotic assisted upper extremity repetitive therapy (RUPERT). Intense, repetitive physical rehabilitation has been shown to be beneficial overcoming upper extremity deficits, but the therapy is labor intensive and expensive and difficult to evaluate quantitatively and objectively. The RUPERT is developed to provide a low cost, safe and easy-to-use, robotic-device to assist the patient and therapist to achieve more systematic therapy at home or in the clinic. The RUPERT has four actuated degrees-of-freedom driven by compliant and safe pneumatic muscles (PMs) on the shoulder, elbow, and wrist. They are programmed to actuate the device to extend the arm and move the arm in 3-D space. It is very important to note that gravity is not compensated and the daily tasks are practiced in a natural setting. Because the device is wearable and lightweight to increase portability, it can be worn standing or sitting providing therapy tasks that better mimic activities of daily living. The sensors feed back position and force information for quantitative evaluation of task performance. The device can also provide real-time, objective assessment of functional improvement. We have tested the device on stroke survivors performing two critical activities of daily living (ADL): reaching out and self feeding. The future improvement of the device involves increased degrees-of-freedom and interactive control to adapt to a user's physical conditions.

A robotic tendon is a spring based, linear actuator in which the stiffness of the spring is crucial for its successful use in a lightweight, energy efficient, powered ankle orthosis. Like its human analog, the robotic tendon uses its inherent elastic nature to reduce both peak power and energy requirements for its motor. In the ideal example, peak power required of the motor for ankle gait is reduced from 250 W to just 77 W. In addition, ideal energy requirements are reduced from nearly 36 J to just 21 J. Using this approach, an initial prototype has provided 100% of the power and energy necessary for ankle gait in a compact 0.95 kg package, seven times less than an equivalent motor/gearbox system.

Purpose The purpose of this study is to assess the effects upon lethal ice (< −30°C) proportions in different heat load phantoms while varying the size and number of cryoprobes at 2 cm spacing. Materials and Methods Thermocouples at 0.5, 1.0 and 1.5 cm intervals from 1.7 or 2.4 mm diameter cryoprobes were held by jigs accommodating 1–4 cryoprobes. Agar phantoms (N=24) used 3 sets of baseline temperatures at approximately 6°C, 24°C and 39°C. Temperatures during 15 minutes freeze cycles were correlated with actual thermocouple locations seen within the ice by computed tomography (CT). Diameters and surface areas of the −30°C lethal isotherm were assessed over time as percentages of the overall iceball. Results The high heat load, 39°C, phantom experiments showed the greatest impact upon percentage lethal zones for all probe configurations. Single, double, triple and quadruple probe arrangements of 2.4mm cryoprobes at 15 minutes had average lethal ice diameters of 1.2, 3.3, 4.1 and 4.9 cm, comprising 13 %, 46 %, 51 % and 56 % surface areas of lethal ice, respectively. Surface areas and diameters of lethal ice made by 1.7mm cryoprobes were 71%and 84% of the 2.4 mm cryoprobes, respectively. Lethal ice resides <1 cm behind the leading edge for nearly all probe configurations and heat loads. Conclusion Single cryoprobes have very low percentages of lethal ice. Multiple cryoprobes overcome both the high heat load of body temperature phantoms and help compensate for lower freeze capacity of thinner cryoprobes.

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Intensive repetitive therapy improves function and quality of life for stroke patients. Intense therapies to overcome upper extremity impairment are beneficial, however, they are expensive because, in part, they rely on individualized interaction between the patient and rehabilitation specialist. The development of a pneumatic muscle driven hand therapy device, the Mentortrade mark, reinforces the need for volitional activation of joint movement while concurrently offering knowledge of results about range of motion, muscle activity or resistance to movement. The device is well tolerated and has received favorable comments from stroke survivors, their caregivers, and therapists.