Design and Simulation of a Novel Magnetic Microactuator for Microrobots in Lab-On-a-Chip Applications

Abstract

This article presents the design of a magnetic microactuator comprising soft magnetic material blocks and flexible beams. The modular layout of the proposed microactuator promotes scalability towards different microrobotic applications using low magnetic fields. The presented microactuator consists of three soft magnetic material (Ni-Fe 4750) blocks connected together via two Polydimethylsiloxane (PDMS) semi-circular beams. A detailed design approach is highlighted giving considerations toward compactness, range of motion and force characteristics of the actuator. The actuator displacement and force characteristics are approximately linear in the magnetic field strength range of 80-160 kA/m. It can achieve maximum displacements of 111.6 µm (at 160 kA/m) during extension and 10.7 µm (at 80 kA/m) during contraction under no-load condition. The maximum force output of the microactuator, computed through a contact simulation, was 404.3 nN at a magnetic field strength of 160 kA/m. The microactuator achieved stroke angles up to 18.4 in a study where the microactuator was integrated with a swimming microrobot executing rowing motion using an artificial appendage, providing insight into the capabilities of actuating untethered microrobots.

A Review on the Motion of Magnetically Actuated Bio-Inspired Microrobots

“…At present, microfluidics is widely used in clinical diagnostics and biomedical research due to the significant advantages in high throughput, miniaturized device size, simplicity, low cost, and portability [1,2]. Microfluidic devices are developed to perform fluidic and particle manipulations [3]. A prominent direction of microfluidics for medical diagnostics is the lab-on-a-chip (LOC) technology [4], which is the study of performing laborious and time-consuming laboratory tasks in a single chip [5].…”

“…From the mentioned actuation methods, magnetic actuation is a widely used actuation method, which is used to mobilize microrobots in biomedical applications [26]. In magnetic actuation, the use of external magnetic fields is considered the most successful approach [3]. This is because low-frequency and lowstrength magnetic fields are not harmful to biological matters including the vital organs in the human body [27], providing the magnetic environment near the microrobot can be achieved using a permanent magnet or an electromagnet.…”