Student: Mr. Aditya Shukla
Research supervisor: Prof G R Jayanth
Date/Time: 7th May 2026, Thursday / 10:30 AM
Venue: SV Narsaiah Auditorium, IAP Department
Title: Analysis of parametrically excited magnetic particles and their 3-D manipulation for micro-robotic applications
Abstract: Micro-robotic systems are used in various fields of science and technology for manipulation of objects of size less than a millimetre. Magnetic tweezers are an example of these systems. They have been employed to characterize properties of intra-cellular organelle owing to its high specificity and biological compatibility. However, this system suffers from limitations of non-linearity, low bandwidth and necessity of visual feedback. To make visual feedback possible the magnetic particle needs to be clearly visible, which may not always be possible. These challenges are addressed by implementing parametric excitation for stable trapping and control of the motion of magnetic particles. Parametric excitation-based systems are modelled by using Mathieu equation, which does not possess analytical solution. In this thesis an analytical framework is developed to obtain approximate solution of Mathieu equation using Floquet theory and harmonic balance, and explore its applicability for advanced manipulation of magnetic particles.
First, the secular motion of the particle is derived for general values of parameters. Next, the secular dynamics is modelled as that of a mass spring damper system, whose parameters are derived using the analytical framework. The derived model is then validated experimentally by trapping a milli-metre scale magnetic particle, qualitatively and quantitatively.
The analysis is then extended for arbitrarily oriented magnetic particle in 3-D. While the dynamics of the magnet gets coupled along the X, Y and Z direction, it is show that the motion can be decoupled by mean of coordinate transformation. The system is found to be stable irrespective of the orientation of the magnetic particle. Stable trapping of arbitrary oriented magnetic particle is validated experimentally and manipulation of the magnetic particle in predefined trajectory is also demonstrated.
Further, trapping of magnetic micro-particles using a micro-ring attached at the free end of a cantilever is numerically investigated. The motion of the magnetic particle and deflection of micro-ring due to coupling between them is studied using harmonic balance and Floquet theory. Stable ranges of frequency of parametric excitation and length of the cantilever are determined. The investigation is also extended for the case of arbitrarily oriented magnetic particle.
Finally, trapping of micro-scale magnetic particle of size 30 μm is demonstrated using a fabricated micro-ring. Trapping of arbitrarily oriented magnetic particle is also demonstrated along with performing pick and place operation. Proof of concept of surface profilometry of a sample and fluid viscosity estimation is also demonstrated using the developed system.