Push recovery control for the underactuated lower extremity exoskeleton based on improved capture point concept

Abstract

Purpose

The purpose of this paper is to use a simple method to enhance the ability of lower limb exoskeletons to restore balance under large interference conditions and to solve the problem that biped robot stability criterion cannot be fully applied to the underactuated lower limb exoskeletons.

Design/methodology/approach

The method used in this paper is to construct an underactuated lower extremity exoskeleton ankle joint with a torsion spring. Based on the constructed exoskeleton, the linear inverted torsion spring pendulum model is proposed, and the traditional capture point (CP) concept is optimized.

Findings

The underactuated exoskeleton ankle joint with torsion springs, combined with the improved CP concept, can effectively reduce the forward stepping distance under the same interference condition, which is equivalent to enhancing the balance ability of the lower extremity exoskeleton.

Originality/value

The contribution of this paper is to enhance the balance ability of the exoskeleton of the lower limbs under large interference conditions. The torsion spring is used as the exoskeleton ankle joint, and the traditional CP concept is optimized according to the constructed exoskeleton.

Citation

Zhang, J., Cong, M., Liu, D., Du, Y. and Ma, H. (2021), "Push recovery control for the underactuated lower extremity exoskeleton based on improved capture point concept", Assembly Automation, Vol. 41 No. 4, pp. 457-465. https://doi.org/10.1108/AA-08-2020-0109