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Abstract Microrobots have the potential for diverse applications, including targeted drug delivery and minimally invasive surgery. Despite advancements in microrobot design and actuation strategies, achieving precise control over their motion remains challenging due to the dominance of viscous drag, system disturbances, physicochemical heterogeneities, and stochastic Brownian forces. Here, a precise control over the interfacial motion of model microellipsoids is demonstrated using time‐varying rotating magnetic fields. The impacts of microellipsoid aspect ratio, field characteristics, and magnetic properties of the medium and the particle on the motion are investigated. The role of mobile micro‐vortices generated is highlighted by rotating microellipsoids in capturing, transporting, and releasing cargo objects. Furthermore, an approach is presented for controlled navigation through mazes based on real‐time particle and obstacle sensing, path planning, and magnetic field actuation without human intervention. The study introduces a mechanism of directing motion of microparticles using rotating magnetic fields, and a control scheme for precise navigation and delivery of micron‐sized cargo using simple microellipsoids as microbots. 

Abstract Induced‐charge electroosmosis (ICEO) offers a practical approach to drive microscale flows by application of AC electric fields across polarizable surfaces, enabling diverse functions including microfluidic pumping, active cargo transport, and biosensing. While ICEO along pristine surfaces is well‐understood, practical applications of ICEO often require surface modifications that affect ICEO flows in a manner that is poorly understood. Here, this study introduces dielectrophoretic (DEP) polarizability measurement, DPM, as a method to study effects of surface modifications on surface polarizability and ICEO flows. The method entails DEP trapping of probe particles and analysis of their equilibrium motions to measure polarizability. This DPM‐generated polarizability data is then used to predict effects of surface modifications on ICEO flows and reveal the contribution of additional factors affecting ICEO. It compares predictions with experimentally observed changes to the speed of Janus particles traveling by ICEO‐driven induced‐charge electrophoresis. This study shows that DPM enables prediction of decreased particle speed upon protein capture by functional Janus particles and reveals that increased speed of polymer‐modified Janus particles likely arises from hydrodynamic factors. Overall, this work lays the foundation for investigating new ICEO‐driven systems with applications in complex environments, potentially including those encountered in biosensing, remediation, or cargo delivery.