Biomedical Science

Miniature robots controlled by magnetic fields

This could pave the way to possible future applications in biomedicine and manufacturing

July 7, 2021
The Scitech

A team of scientists at Nanyang Technological University, Singapore (NTU Singapore) has developed millimetre-sized robots that can be controlled using magnetic fields to perform highly manoeuvrable and dexterous manipulations. The research team created the miniature robots by embedding magnetic microparticles into biocompatible polymers — non-toxic materials that are harmless to humans. The robots are ‘programmed’ to execute their desired functionalities when magnetic fields are applied. The made-in-NTU robots improve on many existing small-scale robots by optimizing their ability to move in six degrees-of-freedom (DoF) – that is, translational movement along the three spatial axes, and rotational movement about those three axes, commonly known as roll, pitch and yaw angles. While researchers have previously created six DoF miniature robots, the new NTU miniature robots can rotate 43 times faster than them in the critical sixth DoF when their orientation is precisely controlled. They can also be made with ‘soft’ materials and thus can replicate important mechanical qualities. The research by the NTU team was published in the journal Advanced Materials in May 2021 and is featured as the front cover of the June 10 issue.

Lead author of the study, Assistant Professor Lum Guo Zhan from the School of Mechanical and Aerospace Engineering said the crucial factor that led to the team’s achievement lie in the discovery of the ‘elusive’ third and final principal vector of these magnetic fields, which is critical for controlling such machines. By contrast, previous works had only defined the applied magnetic fields in terms of two principal vectors. Measuring about the size of a grain of rice, the miniature robots may be used to reach confined and enclosed spaces currently inaccessible to existing robots, say the NTU team, making them particularly useful in the field of medicine. The movements of the robots can be controlled remotely by an operator, using a programme running on a control computer that precisely varies the strength and direction of magnetic fields generated by an electromagnetic coil system. Demonstrating precise orientation control, the miniature robot also recorded a rotation speed of 173 degrees per second for their sixth DoF motion, exceeding the fastest rotation that existing miniature robots have achieved, which is four degrees per second for their sixth DoF motion.

Source: Nanyang Technological University, Singapore