Lead-Lag-Shaped Interactive Force Estimation by Equivalent Output Injection of Sliding-Mode

TL;DR

This paper introduces a novel method for estimating interactive forces in motion control systems using sliding-mode techniques and lead-lag shaping, validated through hydraulic cylinder experiments.

Contribution

It proposes a universal lead-lag shaper combined with sliding-mode output injection for accurate interactive force estimation in complex systems.

Findings

Accurate force estimation demonstrated in hydraulic cylinder experiments.

Method effectively captures interactive forces as external disturbances.

Validated approach improves force estimation accuracy over existing methods.

Abstract

Estimation of interactive forces, which are mostly unavailable for direct measurement on the interface between a system and its environment, is an essential task in various motion control applications. This paper proposes an interactive force estimation method, based on the well-known equivalent output injection of the second-order sliding mode. The equivalent output injection is used to obtain a frequency-unshaped quantity that appears as a matched external disturbance and encompasses the interactive forces. Afterwards, a universal lead-lag shaper, depending on dynamics of the motion control system coupled with its environment, is used to extract an interactive force quantity. Once identified, the lead-lag shaper can be applied to the given system structure. An experimental case study, using a valvecontrolled hydraulic cylinder counteracted by the dynamic load, is demonstrated with an accurate estimation of the interactive force, that in comparison to the reference measurement.