Integral Line-of-Sight Path Following Control of Magnetic Helical Microswimmers Subject to Step-Out Frequencies

TL;DR

This paper presents a novel control method for magnetic helical microswimmers to follow straight-line paths accurately while respecting step-out frequency constraints, using an optimal decision strategy formulated as a trust-region subproblem.

Contribution

It introduces an ODS-based control approach that minimizes velocity error under magnetic saturation constraints, ensuring robust path following with environmental disturbance compensation.

Findings

Effective path following achieved with respect to step-out frequency limits

Control strategy compensates environmental disturbances and drift effects

Ensures smooth and continuous control inputs

Abstract

This paper investigates the problem of straight-line path following for magnetic helical microswimmers. The control objective is to make the helical microswimmer to converge to a straight line without violating the step-out frequency constraint. The proposed feedback control solution is based on an optimal decision strategy (ODS) that is cast as a trust-region subproblem (TRS), i.e., a quadratic program over a sphere. The ODS-based control strategy minimizes the difference between the microrobot velocity and an integral line-of-sight (ILOS)-based reference vector field while respecting the magnetic saturation constraints and ensuring the absolute continuity of the control input. Due to the embedded integral action in the reference vector field, the microswimmer will follow the desired straight line by compensating for the drift effect of the environmental disturbances as well as the microswimmer weight.