Control of a magnetic microrobot navigating in microfluidic arterial bifurcations through pulsatile and viscous flow

Abstract

Abstract-Navigating in bodily fluids to perform targeted diagnosis and therapy has recently raised the problem of robust control of magnetic microrobots under real endovascular conditions. Various control approaches have been proposed in the literature but few of them have been experimentally validated. In this paper, we point out the problem of navigation controllability of magnetic microrobots in high viscous fluids and under pulsatile flow for endovascular applications. We consider the experimental navigation along a desired trajectory, in a simplified millimeter-sized arterial bifurcation, operating in fluids at the low-Reynolds-number regime where viscous drag significantly dominates over inertia. Different viscosity environments are tested under a systolic pulsatile flow compatible with heart beating. The control performances in terms tracking, robustness and stability are then experimentally demonstrated.

Optimal control of multiple magnetic microbeads navigating in microfluidic channels

“…The system consists of three nested sets of Maxwell coils and one nested set of Helmholtz coils [15], and is illustrated in Fig.6(a). Such arrangement allows generating a constant-gradient magnetic field pointing in x, y, and z-axis directions.…”

Uncalibrated Visual Servo Control of Magnetically Actuated Microrobots in a Fluid Environment

“…Belharet et al demonstrate a generalized predictive control (GPC) scheme to actuate a 500 μm neodymium sphere in an endovascular environment using Maxwell and Helmholtz coils in [9] achieving tracking errors on the order of 50-200 μm depending on the fluid composition and flow conditions.…”

Vision-based force sensing of a magnetic microrobot in a viscous flow

“…The EMA setup consists of three nested sets of Maxwell coils and one nested set of Helmholtz coils. These coils set are combined coaxially such that the magnetic field and magnetic gradient fields can be controlled in the center of the workspace [17]. Hence, the magnetic gradient fields generated by the EMA system are controlled through the electrical currents circulating in the coil set.…”

“…Proposed methods usually rely on the measurement of the displacement or deformation retrieved from an imaging sensor. In our context, to ensure efficient navigation control of magnetic microrobot its location is determined from medical imaging such as magnetic resonance imaging (MRI) [15], or digital microscopy [16], [17]. Hence, no additional sensing modalities are required, and the vision sensor is a priori able to provide the force feedback [14].…”