Exoskeleton Robot for Upper Limb Rehabilitation: Design Analysis and Control

Current physical rehabilitation services for stroke utilize a manual hands-on approach with little to no application of modern technology. As a result, physiotherapy treatment is lacking in availability, is highly subjective and can only employ very basic exercises. Increasing efforts are being made in the research and development of rehabilitation robots to address these issues. This research explores the use of an exoskeleton robot for physical rehabilitation of the human upper limb. Analysis of past exoskeleton designs have revealed major limitations in these exoskeletons' shoulder mechanism which limit the range of motion and the movements that can be performed on the shoulder. To overcome the shortcomings of past mechanism designs, a novel 4R mechanism is proposed. However, there are a range of kinematic designs of the 4R mechanism that can meet the performance requirements of a shoulder exoskeleton. To address this, a set of performance criteria are formulated and the NSGA II optimization algorithm is applied to identify an optimal design. The resulting 4R mechanism is capable of reaching the entire shoulder workspace with high performance and without mechanical interference. Performance comparisons with other shoulder mechanism designs confirm the optimized 4R mechanism has superior performance. The optimized 4R mechanism is then used to develop a 5 DOF active exoskeleton system for the shoulder and elbow joints. To maneuver the exoskeleton, an algorithm is developed to generate smooth point-to-point trajectories that are similar to the trajectories in normal human motion. This algorithm is further expanded into a trajectory planner which combines a sequence of point-to-point movements into a single smooth trajectory. To control the exoskeleton, two types of interactive control strategies are developed. Admittance control allows the user's limb to move the exoskeleton by applying forces at the designated interfaces, during which the exoskeleton can assist or resist user movement. Impedance control involves actuation of the exoskeleton to move the user's limb through a specified trajectory with an artificial compliance. Experimental results on a healthy human subject demonstrate the diverse capabilities of the exoskeleton. The tools developed in this research open up new possibilities in the field of physical rehabilitation.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2014

Author dc:creator

• Lo, Ho Shing

Advisors dc:contributor.advisor

• Xie, S
• Haemmerle, E

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/23717

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/23717