A fast and precise micropipette positioning system based on continuous camera-robot recalibration and visual servoing

Micro-biomanipulations rely on fine motion control and precise tool positioning for the execution of delicate operations on biological structures. Appropriate control is typically enabled by the use of micromanipulators; however, manual execution of biomanipulations is difficult, requiring extensive operator training (up to one year) and meticulous work under fatiguing conditions. Automation can be an alternative to improve such operations. In this case, challenges such as interface design, system integration, acquisition of feedback data, and the design of control systems have to be dealt with. This paper concentrates in the later challenge and proposes a new strategy for fast and precise control of the micromanipulation robot. Here, problems related to tool position drift are dealt with using continuous system recalibration. In addition, speed limitations imposed by the vision system are eliminated by the definition of a guaranteed region of interest (gROI) for micropipette localizations. The final system combines the use of mapping functions and visual servoing to achieve a 60% speedup in positioning speed and an 85% reduction in the pipette positioning error. The design and evaluation of this new positioning system is described here, including detail explanations of its modules and their interconnections.