Multivariable Finite-Time Control of 5 DOF Upper-Limb Exoskeleton Based on Linear Extended Observer

An output feedback finite-time control strategy for five degree of freedoms (DOF) upper-limb exoskeleton is investigated in this paper. First, a multivariable second-order sliding mode control is proposed to improve the response speed and stability of the exoskeleton system with parameter uncertainties and external disturbances. Furthermore, for the sake of high control precision with limited information, a finite-time linear extended state observer is constructed to estimate both the unmeasured states and the lumped perturbations. Finally, by utilizing the 5-DOF upper-limb model, simulation results are presented to demonstrate the effectiveness of the control strategy.