Application of Event-Triggered Sliding Mode Control of 2-DOF Humanoid's Lower-Limb Powered by Series Elastic Actuator

TL;DR

This paper introduces an event-triggered sliding mode control combined with backstepping for a 2-DOF humanoid's lower limb powered by a series elastic actuator, enhancing stability and disturbance rejection.

Contribution

It presents a novel control scheme integrating event-triggered SMC with backstepping for humanoid lower limbs with SEA, including stability proof and simulation validation.

Findings

System stability is maintained under external disturbances.

Event-triggered control reduces control updates compared to traditional methods.

Simulations demonstrate improved tracking performance and efficiency.

Abstract

This paper proposes an event-triggered sliding mode control (SMC) scheme combined with a backstepping algorithm for control of 2-DOF humanoid's lower-limb powered by Series elastic actuator (SEA). First, the modelling process for the lower-limb system is implemented by using the Euler-Lagrange theory. With the obtained dynamical equations of lower-limb, the model of the SEA is achieved in both mechanical and electrical perspectives. Then, the event-triggered SMC approach is utilized to ensure the system's stability and eliminate the effect of bounded external disturbance. Next, some assumptions and designed thresholds for the tracking error are given, together with the proof for the convergence of the inter-event time. The backstepping algorithm is applied in the end to determine the needed input control voltage signal. Finally, the results of this research are demonstrated through some simulations in order to prove the effi-ciency and appropriation of this method.