P2.6 - Structurally integrated joint torque sensors in an assistive upper limb exoskeleton

Event
AMA Conferences 2017
2017-05-30 - 2017-06-01
Nürnberg, Germany
Band
Proceedings Sensor 2017
Chapter
P2 - Mechanical Sensors
Author(s)
M. Hessinger, J. Krenzer, E. Christmann, J. Hielscher, M. Kupnik, R. Werthschützky - Technische Universität Darmstadt (Germany)
Pages
593 - 593
DOI
10.5162/sensor2017/P2.6
ISBN
978-3-9816876-4-4
Price
free

Abstract

This paper describes the design process of a torque sensor, which is structurally integrated into the kinematic chain of an assistive upper limb exoskeleton to measure user interaction. Two different approaches of torque sensor integration are discussed regarding the nominal torque loads on each joint and applied transverse stresses. The final sensor concept consists of an aluminum spoke wheel deformation element with four strain gauges connected to a Wheatstone bridge. It is mounted between the motor casing and gear drive of each joint to measure the torque of the actuator and user. A sensor electronics board including signal processing and an EtherCAT interface is integrated in each joint. The torque sensor shows linear transmission characteristics for 0.4 Nm nominal rated torque with a linear error of 0.51 % and a hysteresis error of 0.53 %.

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