This paper introduces a compact, wireless, wearable system that measures signals indicative of forces, torques and other descriptive and evaluative features that the human body undergoes during bursts of extreme physical activity (such as during athletic perfor-mance). Standard approaches leverage highspeed camera systems, which need significant infrastructure and provide limited update rates and dynamic accuracy. This project uses 6 degree-offreedom inertial measure-ment units worn on various segments of an athlete’s body to directly make these dynamic measurements. A combination of low and high range sensors enables sensitivity for both slow and fast motion, and the ad-dition of a compass helps in tracking joint angles. Data from the battery-powered nodes is acquired using a custom wireless protocol over an RF link and analyzed offline. Several professional pitchers and batters were instrumented with the system and data was gathered over many pitches and swings. We show some biome-chanically descriptive parameters extracted from this data, and highlight ongoing work and system impro-vements.

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After neurological injury such as stroke, upper limb paresis and loss of hand function leads to lower activity of the paretic limb and loss of independence. The strength of the paretic upper limb is strongly related to measures of activity. Robot-assisted therapy, along with augmented reality leads to increased motivation to perform exercises and improvements in motor function, but costs are high so clinical uptake is rare. A device was developed to allow a computer to control the exercise effort for a table-top, augmented reality therapy based on a computerised arm-rehabilitation skate. Various methods of applying and controlling the therapeutic exercise effort have been evaluated in designing the device, which should be portable and suitable for home based use. A vision based motion tracking system captures the movement of the device, so a computer can be used to monitor and control the exercise effort. The novel design of the rehabilitation system allows computer controlled resistance to movement, as well as integration with exercise stimulating games and windows-based tasks. This provides the patient with a home-based exercise platform which provides stimulating experience in his/her physiotherapy.

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Force sensing is an essential requirement for dexterous robot manipulation. We describe composite robot end-effectors that incorporate optical fibers for accurate force sensing and estimation of contact locations. The design is inspired by the sensors in arthropod exoskeletons that allow them to detect contacts and loads on their limbs. In this paper, we present a fabrication process that allows us to create hollow multimaterial structures with embedded fibers and the results of experiments to characterize the sensors and controlling contact forces in a system involving an industrial robot and a two-fingered dexterous hand. We also briefly describe the optical-interrogation method used to measure multiple sensors along a single fiber at kilohertz rates for closed-loop force control.

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Series Elastic Actuators provide many benefits in force control of robots in unconstrained environments. These benefits include high force fidelity, extremely low impedance, low friction, and good force control bandwidth. Series Elastic Actuators employ a novel mechanical design architecture which goes against the common machine design principal of “stiffer is better”. A compliant element is placed between the gear train and driven load to intentionally reduce the stiffness of the actuator. A position sensor measures the deflection, and the force output is accurately calculated using Hooke’s Law (F=Kx). A control loop then servos the ac-tuator to the desired output force. The resulting actuator has inherent shock tolerance, high force fidelity and extremely low
impedance. These characteristics are desirable in many applications including legged robots, exoskeletons for human performance am-plification, robotic arms, haptic interfaces, and adaptive suspensions. We describe several variations of Series Elastic Actuators that have been developed using both electric and hydraulic components.

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Current State of Powered Gait Devices.

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