Constant torque gravity compensation

Constant torque gravity compensation: Designing a wrist support for Duchenne Muscular Dystrophy patients

van der Burgh, Bas (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Precision and Microsystems Engineering; TU Delft Biomechanical Engineering)

Radaelli, G. (mentor)
Filius, S.J. (mentor)
Harlaar, J. (mentor)
Smit, G. (graduation committee)
Farhadi Machekposhti, D. (graduation committee)

Delft University of Technology

Mechanical Engineering | Mechatronic System Design (MSD)

2022-10-25

Duchenne Muscular Dystrophy (DMD) patients suffer from a severe form of progressive muscular weakness. Consequently, as the disease progresses these patients become more and more dependent on assistive devices for their daily activities. For instance lifting their arms against gravity already becomes challenging. So far, a considerable amount of effort has been put in the development of assistive devices. However, compensating the weight of the hand remains challenging as the required balancing torques are dependent on the position of the hand and the orientation of the forearm.

In this research a solution is proposed to passively compensate the weight of the hand by making use of a simplified torque profile (a constant torque). The effectiveness of this profile was assessed experimentally in a group of healthy subjects. For this the wrist muscle activity required to lift the hand against gravity was measured through surface electromyography, for several types of compensation. From this experiment the conclusion can be drawn that a constant torque profile performs similar to the theoretically ideal type of balancing, showing a similar reduction in the anti-gravity muscle activity.

Based on these findings, a mechanism has been developed capable of providing an adjustable constant force, by making use of a combination of positive and negative stiffness springs, for implementation in a wrist support for DMD patients.

Gravity compensation
Wrist support
Duchenne muscular dystrophy
Surface EMG
Adjustable constant force
Negative Stiffness

http://resolver.tudelft.nl/uuid:cd089772-150a-49ab-833c-681e9c368dd3

2024-01-01

Student theses

master thesis

© 2022 Bas van der Burgh