|Academic Profile |
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Asst Prof Lum Guo Zhan
Assistant Professor, School of Mechanical & Aerospace Engineering
|Lum Guo Zhan received his B.Eng. with first class honors in mechanical engineering from Nanyang Technological University in 2010. He went on to pursue his postgraduate studies in mechanical engineering under the dual Ph.D. program of Nanyang Technological University and Carnegie Mellon University. He received his M.Sc. degree from Carnegie Mellon University in 2015, and dual Ph.D. degrees in 2016. From May 2016 to December 2017, he was a post-doctoral researcher at the Max Planck Institute for Intelligent Systems in Germany. During his Ph.D. and post-doctoral phases, he has worked on several research projects pertaining to soft miniature robots, magnetic micro-robots, high precision micro/nano-positioners, and also highly reversible and switchable adhesives. To date, he has published eight journal papers, including multi-disciplinary journals such as Nature, PNAS and Advanced Materials. One of his works was nominated for the best paper award at the 2014 Robotics: Science and Systems conference. His work on miniature soft robots, and highly reversible and switchable adhesives have also attracted substantial attention from the international media.|
|The three main research topics in our lab are: 1. shape-programmable millimeter-scale robots, 2. gallium and 3. flexure mechanisms for high precision applications.|
1. Shape-Programmable Millimeter-scale Robots
Shape-programmable robots are machines that can be excited by external stimuli to generate desired time-varying shapes. These robots are especially appealing at small-scale because they have great potential to achieve functionalities unattainable by their rigid counterparts.
As these miniature soft robots can easily access confined spaces within the human body, they show great promise to realize revolutionary biomedical applications such as targeted drug delivery and minimally-invasive surgeries. While there exists many different types of actuation, here we are particularly interested in using remote magnetic fields to control our robots. In contrast to other methods, magnetic actuation offers higher control authority as the actuating fields can be controlled not only in their magnitude but also in their direction and spatial-gradients. Furthermore, this actuation method will be compatible for our targeted medical applications as the actuating magnetic fields can easily and harmlessly penetrate through biological tissues.
Heading towards these biomedical applications, we have previously developed a universal design method that can program the magnetization profile and actuating fields for our robots to achieve their specified functionalities. However, to enhance the practicality of these robots, we will continue to develop new design methods to further enhance their functionalities.
Gallium is a class of liquid metal that can be attached to millimeter-scale robots to enhance their functionality. In our previous research, we discovered that gallium can exhibit highly reversible and switchable adhesion when it undergoes a solid–liquid phase transition. It has been demonstrated that this liquid metal can become highly adhesive when it freezes and it can conversely lose its adhesion when it melts. These adhesive properties had been characterized, and we experimentally show that gallium has good performance over a wide range of smooth and rough surfaces, under both dry and wet conditions.
Another critical advantage of gallium is that it has a natural layer of oxide, which acts like an elastic membrane surrounding the liquid metal. This oxide layer can effectively conserve the mass of gallium when it is in the liquid-state, and this in turn ensures that gallium can be used repeatedly as a reversible and switchable adhesive. The unique adhesive properties of gallium can therefore allow it to perform various pick-and-place tasks at small-scale, which are critical for numerous applications in transfer printing, robotics, electronic packaging, and biomedicine.
We believe there are still many interesting abilities in gallium, which have not been discovered yet. Therefore, we will continue to explore new abilities of this material and transform them into critical functions for miniature robots.
3. Flexure Mechanisms
Flexure mechanisms are flexible structures that are designed to deliver desired motions via elastic deformations. Due to their unique actuation, these structures can effectively eliminate backlash and dry friction, allowing them to achieve highly repeatable motions. As a result, flexure mechanisms have become the ideal candidates for constructing high precision robotic systems, and they have been deployed across a wide range of applications pertaining to biomedical research, microscopy technologies and various industrial manufacturing processes.
From the design perspective, the performances of many existing flexure mechanisms are still not optimal. Hence, here we will explore new design methods that can successfully address such issues such that engineers can fully utilize such machines.
- Design Automation for Optimal Miniature Soft Robots
- Optimal Flexure Mechanisms for High Precision Micro/Nano-Positioning Applications
- Wenqi Hu*, Guo Zhan Lum*, M. Mastrangeli, Metin Sitti (*Co-First Authors). (2018). Small-scale soft-bodied robot with multimodal locomotion. Nature, 554(7690), 81.
- Lindsey Hines, Kirstin Petersen, Guo Zhan Lum, Metin Sitti. (2017). Soft Actuators for Small-Scale Robotics. Advanced Materials, 29(13), 1603483.
- Guo Zhan Lum*, Zhou Ye*, Xiaoguang Dong*, Hamid Marvi, Onder Erin, Wenqi Hu, Metin Sitti (*Co-First Authors). (2016). Shape-Programmable Magnetic Soft Matter. Proceedings of the National Academy of Sciences of the United States of America (PNAS), 113(41), E6007.
- Zhou Ye*, Guo Zhan Lum*, Sukho Song, Steven Rich, Metin Sitti (*Co-First Authors). (2016). Phase Change of Gallium Enables Highly Reversible and Switchable Adhesion. Advanced Materials, 28(25), 5088.
- Guo Zhan Lum, Tat Joo Teo, Song Huat Yeo, Guilin Yang, Metin Sitti. (2015). Structural optimization for flexure-based parallel mechanisms – Towards achieving optimal dynamic and stiffness properties. Precision Engineering, 42, 195.