The Research Of A Micro-manipulating System Based On A Micro-object Manipulation

In the field of biological engineering, many operations on micro organism under microscope are needed. In the most of fields the operations are completed by manual. Sometimes the accuracy of the moving displacement needs to be micro-grade and even nano-grade, manipulation will spend the skilled operator much time when working under microscope, they are easily to fatigue and that will lead to the low efficiency and low success rate. In the paper, the micro-manipulation system that can complete an operation automatically for cells puncture is developed. The micro-manipulation system is composed of vision feedback system (auto-focusing) and micro-manipulation tools and its control technology.In this paper, an auto-focusing system has been developed for a micro-manipulation platform with the visual feedback system, based on digital image processing technology. Considering the current status of development at home and abroad, we applied an AF(Automatic Focusing) algorithm with high precision, using shape memory alloys(SMA) as a micro-drive. The micro-manipulation system is consisted of the visualization system, human-machine interface and a micro-manipulator. It can not only keep on real-time monitoring, but also accurately find the target with several microns.In the auto-focusing process, we make use of automatic location evaluation function which based on intensity function, whether the image's location is accurate based on the differences between object and background. We applying a focusing evaluation function, it combined energy with high frequency information as well, the image became the most distinctive when it reaches the maximum. This method has good sensitivity and accuracy, but also has good operability; it can be used for micro operation platform.As the driver of the micro-manipulation system, we analysis the current-strain properties of the SMA tool, and apply position feedback to control the current of SMA, and then control the move of SMA. In order to decrease the SMA cooling time, Semiconductor Refrigerator is applied to cool the SMA, it helps to improve the work efficiency and accurate. Experiments results show the relationship between the current of SMA with the micro-manipulator rate at different frequencies, and the displacement curve over time. Finally, the accuracy and various properties of the SMA micro-manipulator are given out.