Design And Implementation Of Automatic Multi-channel High Precision Dispensing System

Dispensing systems are widely used in beverage packaging, food production, clinical care, biochemical experiments, drug development and other fields, especially in clinical medicine, in order to ensure the accuracy of test results requires high-precision and non-pollution micro-liquid dispensing device was performed to separate operation. In our country the quantity of micro-dispensing system is small, the accuracy of the existing instruments is not high and the stability is poor; the current market of high-precision dispensing system has been mostly producted by foreign companies, but expensive and bulky. Therefore, independently developed a compact, low-cost and efficient micro-dispensing system, has a high social value and economic benefits.The thesis choses ARM+FPGA architecture, and designs a fully automatic, high-precision, non-pollution micro-dispensing system. By designing high-precision module which integrates pump and valve, the system effectively improves the equipment's dispensing precision and reduces the cost; by designing the module which probes the liquid level using the capacitor way,it significantly reduces the phenomena of liquid leakageing dispensing, cross contamination of different liquid and liquid hanging in liquid suspension needle, and improves the precision futher; Build soc system,by designing the control logic in FPGA, it implements driving the motors, sensor and other devices. By transplanting Linux operation system, Qt GUI development library and lightweight SQLite datebase to development board, it implements the design of the instrument host control software; by developing the control software in a mobile phone, it implements the remote control and information management of the instruments, ensuring the safety of operator effectively in the environment of dispensing poisonous and harmful liquid.The main contribution of the thesis are:(1)according to the pump's principle, proposed segmented compensation method to eliminate dispensing errors of motor's lose steps or compressed air, bring improved dispensing accuracy;(2)for the problems of cross-contamination presence during dispensing,using the capacitors-duty cycle conversion to achieve liquid level's precision probe;(3) for the problems of separation for toxic and hazardous liquids possible threaten the safety of the operator, using advanced multi-terminal control method, implemented flexible control of the instrumentThe thesis realizes efficient micro-dispensing system design,the system realizes equipment's features, such as automatic dispensing, washing, maintenance, multi-terminal control and so on, and control software has clear structure, friendly interface. After repeated testing and certification, the system can reach 450 holes / hour dispensing speed, dispensing magnitude 5ul, the liquid level detection accuracy of 99.6%. The system has reached the requirements of the cooperative company.