高精度小型酶联免疫分析仪微量进样系统设计

为提高酶联免疫分析仪微量进样的可靠性与精度，自主研发了一种小型微量自动进样系统。采用丝杆与进样器活塞杆错位平行分布的方式，设计了精巧的进样机构，实现移液和取、退吸头的功能；利用STM32核心控制器，实现了单轴的S型加减速控制以及多轴协调、多线程运动控制；利用分段的方法对加减速曲线进行分析与优化，实现系统最小进样量为1 μL，以0.05 μL的进样分辨率步进；通过试验校验了进样臂的位置精度与进样精度，采用最小二乘线性拟合方法对系统进样误差进行补偿校正。研究结果表明：优化后的S型加减速算法改善了步进电机的运动特性，有效避免了失步与过冲现象，使进样机构具有较高的位置精度；误差补偿后的微量进样系统拥有更高的进样精度与稳定性，在检定进样量为10，50，100 μL时的进样精度分别由±7.2%，±5.3%，±3.2%提高到±1.8%，±1.28%，±1.15%，满足仪器小型化、高精度的设计要求，具有良好的实际应用与推广价值。

Design of micro-sampling system with high precision for small enzyme immunoassay analyzer

To improve the reliability and accuracy of the automatic enzyme immunoassay analyzer's micro-sampling system, a small autoinjection system was developed. A sophisticated injection arm was designed by the means of dislocation parallel distribution of the screw and injector piston rod. It possessed the function of pipetting, taking and removing the pipette tips. In the control system STM32 controller was used, controlling the single-axis S-type acceleration/deceleration algorithm and multithreaded coordinated motion. The acceleration/deceleration curves were analyzed and optimized by using the method of segmentation, the minimum injection rate of 1 μL was realized and the step rate was 0.05 μL. The position accuracy and the sampling precision of the injection system were verified by experiments, and the least squares linear fitting method was used to compensate the system sampling error. The results showed that the optimized S-type acceleration and deceleration algorithm could improve the motion characteristics of the stepping motor, avoiding the out-of-step and overshoot effectively, and the injection arm could reach a reliable position accuracy. The microinjection system had higher accuracy and stability after error compensation, at the test point 10, 50, 100 μL, the injection precision increased respectively from ±7.2%, ±5.3%, ±3.2% to ±1.8%, ±1.28%, ±1.15%. The system meets the miniaturization and high-precision design requirements, which has good application and popularization value.