Abstract

Exoskeleton robots are complex electro-mechanical devices designed to interact with the human for the purpose of power amplification, movement correction and rehabilitation applications. While many designs of upper body exoskeleton have been proposed, developing an exoskeleton robot of high reliability, safety and comfortability remains as a challenging task. Therefore, new mechanisms and test methods that could simplify the exoskeleton development and evaluate the influence of these parameters are required.

The overall objective of this Ph.D. thesis focuses on developing comprehensive support for the human upper limb movements, including hand opening/closing, and investigating their implications as part of physical human-robot interaction (pHRI). Thus, three studies were conducted, where fully powered and hybrid methods of actuation were investigated to support the human upper limb movements.

The first study proposes a novel design of a 4-DOF active/powered upper limb exoskeleton for physical assistance. A prototype of the active upper limb exoskeleton was developed, and a commercially available soft extra muscle (SEM) glove was integrated to supplement the users in grasping; thus, fulfilling the requirement for comprehensive motion support. The design was tested for two basic activities of daily living (ADL), i.e., drinking and picking up an object from the table. The experiments demonstrated the effectiveness of using the proposed system for physical assistance.

The second study focused on investigating the physiological consequences of using upper limb exoskeleton on the human upper limb skeletal system using a multibody modeling approach. A mathematical model was developed to simulate the dynamic interaction between the human upper limb and exoskeleton system for manual load lifting activities. Upon simulations, a new method of developing a hybrid upper limb exoskeleton was proposed, which offers relatively a cost effective, lightweight, and low-power solution.

In the third study, a new design of a hybrid hand exoskeleton designed to amplify the residual movements or restore the lost motor function for hand opening/closing is implemented and evaluated. The prototype was developed and tested with the two healthy participants and two patients suffering from amyotrophic lateral sclerosis (ALS). Moreover, flex sensors were used to record the fingers joint angle trajectories for simple hand opening task. The statistical analysis of the recorded joint angle trajectories showed that the hybrid exoskeleton supported the patients during the hand opening and compensated for the relative hyperflexion of the fingers and wrist muscles.

The work described in this thesis contributes to the design and biomechanical evaluation of upper limb exoskeletons that can support human upper limb movements comprehensively. As a result, two novel hybrid exoskeleton designs were proposed, resulting in a low-power, cost-effective solutions. The research reported in this thesis demonstrates the efficacy of newly proposed hybrid exoskeletons as alternatives to existing fully powered and sophisticated systems. The work will thus pave the way for future study and aid in the development of more accurate knowledge of human-robot interaction.

 

Assessment Committee      

Associate Professor Brian Lau Verndal Bak
Aalborg University
Denmark

Professor Christoph Russmann
HAWK University of Applied Science and Arts
Germany

Senior Lecturer Guangbo Hao
University College Cork
Ireland

 

Supervisor

Professor Shaoping Bai
Department of Materials and Production
Aalborg University

The PhD defense will be hosted by Moderator associate professor Brian Lau Verndal Bak. The lecture constitutes a 45 minutes presentation by Muhammad Ahsan Gull followed by a short break and a discussion session with questions from the opponents and the auditorium.

After the defense the department host a small reception in Fibigerstræde 14, common room.

Participation online is possible:

Microsoft Teams-meeting