Upper-Limb Powered Exoskeleton

An external structural mechanism with joints and links corresponding to those of a human. The exoskeleton is an external structural mechanism with joints and links corresponding to those of the human body. The exoskeleton transmits torques from proximally located actuators through rigid exoskeletal links to the human joints. The human–machine interface (HMI) of the operator/exoskeleton is designed to generate natural operation of the device. Given the exoskeleton mechanism and the selected application, various control algorithms were proposed (position, force–impedance).

University of Washington

Specifications

Degrees of freedom (DOF) 7
Weight6.8 kg
Static Payload (max)2.5 kg
Angular Deflection (max) 2 degrees per joint
Bandwidth 0-10 Hz

Overview

The exoskeleton is an external structural mechanism with joints and links corresponding to those of the human body. The exoskeleton transmits torques from proximally located actuators through rigid exoskeletal links to the human joints.

The human–machine interface (HMI) of the operator/exoskeleton is designed to generate natural operation of the device. Given the exoskeleton mechanism and the selected application, various control algorithms were proposed (position, force–impedance). To trigger motion in the exoskeleton, these control strategies require the operator to either move part of his/her upper limb, or apply a force on the exoskeleton system.

Proximal placement of motors and distal placement of cable-pulley reductions are built into the design, leading to low inertia, high stiffness links, and backdrivable transmissions with zero backlash. The design enables full glenohumeral, elbow, and wrist joint functionality.

Potential applications of the exoskeleton as a wearable robot include use as: 

  • a therapeutic and diagnostics device for physiotherapy
  • an assistive (orthotic) device for human power amplification
  • a haptic device in a virtual reality simulation
  • a master device for teleoperation.

References

Describes the development of the anthropometric seven degree-of-freedom powered exoskeleton for the upper limb.

J. Perry, J. Rosen. - The First IEEE/RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics, 2006.

The design of the system was guided by experimental results of a research study on the kinematics and dynamics of the human arm in daily living activities. Details of the pilot study are explained, followed by a description of the resulting design requirements and additional system requirements. A d

J. Perry, J. Rosen, S. Burns. - eee/asme transactions on mechatronics, August 2007.

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