Design of an Optimal 4-bar Mechanism Based Gravity Balanced Leg Orthosis
- 159 Downloads
In this paper we propose the design and control of a 4-bar mechanism based gravity balanced orthosis for providing gait training to persons with disability. Human leg joints have a varying instantaneous centre of rotation and hence 4-bar mechanisms have been used to actuate the orthosis joints. Human gait is first recorded using a vision system and the hip and knee joint trajectories extracted from the data. Optimal 4-bar mechanisms are then designed using a genetic algorithm that gives the smallest mechanism that can replicate the hip and knee joint trajectories accurately. The orthosis joints are gravity balanced so that the potential energy of the system in any orientations is constant, and the wearer does not feel the weight of the system. Experimental and simulation results prove that the exoskeleton can effectively model the changing centre of rotation of the hip and knee joints and follow the desired human trajectories.
Keywords4-bar mechanism Leg orthosis Gravity balancing Human gait
Unable to display preview. Download preview PDF.
- 4.Chu, A., Kazerooni, H., Zoss, A.: On the biomimetic design of the berkeley lower extremity exoskeleton (BLEEX). IEEE International Conference on Robotics and Automation, 4345–4352 (2005)Google Scholar
- 6.Suzuki, K., Mito, G., Kawamoto, H., Hasegawa, Y., Sankai, Y.: Intention-based walking support for paraplegia patients with robot suit HAL. Adv. Robot. 21(12) (2007)Google Scholar
- 17.Chen, J., Liao, W.H.: Design and control of a magnetorheological actuator for leg exoskeleton. IEEE International Conference on Robotics and Biomimetics, 1388–1393 (2007)Google Scholar
- 18.Wu, S.K., Jordan, M., Shen, X.: A pneumatically-actuated lower-limb orthosis. IEEE International Conference on EMBS, 8126–8129 (2011)Google Scholar
- 24.Chen, B., Ma, H., Qin, L.Y., Gao, F., Chan, K.M., Law, S.W., Qin, L., Liao, W.H.: Recent developments and challenges of lower extremity exoskeletons. J. Orthop. Trans. 5, 26–37 (2016)Google Scholar
- 25.Norton, R.L.: Design of machinery: An introduction to the synthesis and analysis of mechanisms and machines, 3rd edn. McGraw-Hill Higher Education (2004)Google Scholar