Design and Control of an Exoskeleton with Flexible Links for Upper Limb Movement Rehabilitation

The authors of this paper propose the development of an upper-limb exoskeleton with flexible links, aiming to reduce the mass and size of actuators, resulting in a lighter, more compact, and accessible device. The flexibility of the links will be explored as a resource to improve interaction control. Unlike the previous paradigm, where link flexibility was considered a disadvantage, in this project, it will be regarded as a beneficial characteristic capable of providing more stable and transparent interaction control. The use of link flexibility for interaction control is an area that remains underexplored in the literature, and this study seeks to fill that gap. To address the complexity of controlling flexible robots, H_∞ control techniques will be employed to ensure the system's robustness against parametric uncertainties and external disturbances. Simulated results from implementing a H_∞ impedance controller on an actuator with a series elastic link demonstrate the feasibility of the proposal.