Coordinated Optical Tweezing and Manipulation of Multiple Microscopic Objects With Stochastic Perturbations

Abstract

The Brownian motion of micro-objects in fluid mediums is a fundamental distinction between optical manipulation and robotic manipulation in the macro-world. Besides, current control techniques for optical manipulation generally assume that the manipulated micro-objects are initially trapped prior to the manipulation processes. This letter proposes a robotic control technique for fully automated optical trapping and manipulation of multiple micro-objects with stochastic perturbations. Cooperative control of robotic stage and optical traps is performed to achieve the control objective, in which multiple micro-objects are trapped in sequence by using the robotic stage, and the trapped micro-objects are then manipulated toward a desired region by using laser-steering system. The transition from the trapping operation to manipulation of the trapped micro-objects is fully automated. In this letter, a closed-loop control approach of the optical traps is formulated, and thus ensuring the completeness of the manipulation tasks. The stability of the control system is investigated from a stochastic perspective, and the performance of the proposed control technique is illustrated with experimental results.