A rolled-up-based fabrication method of 3D helical microrobots

Zihan Wang; Xueliang Mu; Liyuan Tan; Yukun Zhong; U Kei Cheang

doi:10.3389/frobt.2022.1063987

A rolled-up-based fabrication method of 3D helical microrobots

Front Robot AI. 2022 Nov 29:9:1063987. doi: 10.3389/frobt.2022.1063987. eCollection 2022.

Authors

Zihan Wang^{1

2}, Xueliang Mu^{1

3}, Liyuan Tan¹, Yukun Zhong¹, U Kei Cheang^{1

4

5}

Affiliations

¹ Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, China.
² Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands.
³ Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB, Canada.
⁴ Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Southern University of Science and Technology, Shenzhen, China.
⁵ Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities, Southern University of Science and Technology, Shenzhen, China.

Abstract

While the potential of using helical microrobots for biomedical applications, such as cargo transport, drug delivery, and micromanipulation, had been demonstrated, the viability to use them for practical applications is hindered by the cost, speed, and repeatability of current fabrication techniques. Hence, this paper introduces a simple, low-cost, high-throughput manufacturing process for single nickel layer helical microrobots with consistent dimensions. Photolithography and electron-beam (e-beam) evaporation were used to fabricate 2D parallelogram patterns that were sequentially rolled up into helical microstructures through the swelling effect of a photoresist sacrificial layer. Helical parameters were controlled by adjusting the geometric parameters of parallelogram patterns. To validate the fabrication process and characterize the microrobots' mobility, we characterized the structures and surface morphology of the microrobots using a scanning electron microscope and tested their steerability using feedback control, respectively. Finally, we conducted a benchmark comparison to demonstrate that the fabrication method can produce helical microrobots with swimming properties comparable to previously reported microrobots.

Keywords: controllable; feedback control strategy; helical microrobots; rolled-up technology; swelling effect.