| Owing to the merits of non-invasiveness and full participation in the clinical treatment process,the detection of circulating tumor cells has important scientific significance and research value for tumor screening,prognostic evaluation and efficacy evaluation.Highprecision scanning motion control is the key to the detection of circulating tumor cells based on fluorescence microscopy imaging.However,the impact of residual vibration in the high-precision scanning process can result in the decrease of the positioning accuracy and detection efficiency of biological samples.Therefore,a high-precision scanning platform motion control method with high positioning accuracy and low residual vibration is in urgent request.Based on the principle of fluorescence scanning detection of circulating tumor cells,the hardware and software foundations of the motion control system were constructed,including the mechanical structure and software program.Aiming at eliminating the impact and residual vibration in the fluorescence scanning imaging detection of circulating tumor cells,a planning algorithm of platform motion curve control based on the optimal order polynomial was designed.In addition,the residual vibration experiment of the scanning platform and the scanning imaging experiment of biological samples were carried out.The main research contents of this article are summarized as follows:(1)The mechanical structure of the support structures,the sampling module,and the optical detection channel switching module were designed based on the principle of fluorescence scanning detection of circulating tumor cells.Then,the static simulation analysis of the leveling mount mechanical parts was carried out,which established the mechanical foundation of the motion control system.The host computer control software was written via the object-oriented C# language so that the upper and lower computers could transfer control instructions and data through the serial port.The control program part of motion control system was built based on STM32F407,and the control programs of lower computer for sampling,focusing,optical detection channel switching,and scanning platform motion control module were also designed to realize accurate and reliable motion control of each module.(2)The motion curve planning algorithm was developed for the flexible scanning platform composed of the sampling structure and the two-dimensional scanning platform.Through the analysis of the existing motion curve,the motion curve model was determined to be a polynomial model,and the Matlab/Simulink module was used to analyze the residual vibration and settling time of the flexibility scanning platform.After analyzing the relationship among the number of motion curve segments,residual vibration and settling time,the order of the optimal polynomial motion curve of the scanning platform was determined to be fourth order and the fourth-order polynomial motion curve analysis formula was established.(3)Experimental verification of the motion control system was performed,including the control system function verification,the residual vibration test of the flexible scanning platform,the repeated positioning accuracy of the scanning platform and the measurement of scanning imaging accuracy.The experimental results show that the control system works well in sample entry and exit,focusing,optical detection channel switching and scanning platform motion control.Compared with the trapezoidal motion curve,the polynomial motion curve with the optimal order of the fourth order reduces the peak value of acceleration and the settling time by 67.92% and 49.92.%,respectively.Compared with the third-order polynomial motion curve,the peak value of acceleration decreases by 42.94%and the steady-state time reduces by 32.5%.Besides,the repetitive positioning accuracy of the scanning platform in the X direction is about ±0.67 μm,and the scanning imaging accuracy is about ±1.706 μm,In the Y direction,the repositioning accuracy is about ±0.84μm,and the scanning imaging accuracy is about ±1.492 μm.Furthermore,fluorescence scanning and imaging of biological samples were performed.The experimental results show that this system can perform rapid fluorescence scanning and imaging of circulating tumor cells well,which has great application value. |
