Development of an upper limb exoskeleton for rehabilitation and training

D. Chakarov, P. Venev, M. Tsveov, I. Veneva

Abstract: This work involves the development of an upper limb exoskeleton designed for rehabilitation and training. In the first stages of rehabilitation when the patient is unable to move alone, the exoskeleton must be stiff while in the next stages it should be able to respond to any movement made by the patient. Key feature here is transparency: the robot must be able to “hide” if the patient is capable of making the movement without assistance. In this context, the aim of the work is to find and evaluate an appropriate solution for the design of an exoskeleton that provides an accurate force feedback and achieves transparency and natural safety. In the work, the mechanical structure and actuation of an exoskeleton arm are considered. The proposed design of the exoskeleton arm with serial electric and pneumatic drive allows to change the robot impedance in a passive way and to vary between high and low impedance control modes. The impedance control is proposed taking into account the passive compliance of pneumatic actuation. Simulations and evaluations of interaction force between patient and exoskeleton as a result of device passive impedance are conducted. Here an assessment of the interaction force as a result of exoskeleton gravity and exoskeleton elastic properties is made. Transparency is evaluated in different directions, depending on the arm posture and the end effector compliance. Finally, conclusions and future works are given.


Series on Biomechanics, Vol.32, No.4 (2018), 11- 18

Keywords: Exoskeleton; rehabilitation; transparency

Date published: 2019-02-01