Robust orientation control of multi‐DOF cell based on uncertainty and disturbance estimation

Mingyang Xie,  Adnan Shakoor,  Chuntao Li,  Dong Sun

Multiple degrees‐of‐freedom (multi‐DOF) cell orientation control is a vital important technique involved in single cell surgery applications. Currently, few studies have been performed toward automation of multi‐DOF cell orientation control using robotically controlled optical tweezers. In this paper, a robust control framework is developed to perform multi‐DOF cell rotational control with consideration of model uncertainties and external disturbances. Both simulation and experimental studies are presented to illustrate the performance of the proposed control strategy. The main contributions of this work lie in that this is the first time to develop a unified framework to achieve multi‐DOF cell orientation control without the need for accurate dynamic model parameters and/or any knowledge about uncertainty characteristic, which greatly enhances the robustness of the overall system.

DOI

A simple control scheme for the manipulation of a particle by means of optical tweezers

Carlos Aguilar-Ibañez, Miguel S. Suarez-Castanon, Luis I. Rosas-Soriano

We present a simple control scheme for changing the position of a microscopic particle immersed in a viscous medium and trapped by optical tweezers. We derive a simple feedback controller under the consideration that the particle mass is so small that it can be discarded from the motion equations. This approximation is well justified in practice, since the inertial force produced by the motion of a micron-scaled trapped particle is completely dominated by the medium viscous drag force. Finally, we formally prove that the obtained controller is able to globally asymptotically stabilize the system when the particle mass is considered, if some suitable values of some control parameter are used. The stability analysis of the controlled system was carried out by using the standard Lyapunov stability theory. Also, by means of numerical simulations, we show that the obtained closed-loop system is robust when random thermal noise is presented.

DOI