The Design Of High Precision Micro-liquid Sampling Device

In recent years, with the development of science and technology, the clinicalmedicine in China has made great progress at the same time. All kinds of automaticdetecting instruments step on the scientific stage, and as the necessary device of clinicaldiagnosis automatic detecting instrument—micro-liquid sampling device, its precisiondemand becomes higher and higher. By analyzing the working principle and designrequirements of micro-liquid sampling device, this thesis chooses a Single-ChipMicrocomputer as the core of control system, designs and manufactures ahigh-precision micro-liquid sampling device. This device, which aimed at suck sampleaccurate quantitatively, can not only apply for all kinds of chemiluminescence’sanalyzers, but also apply for other micro-liquid sampling device.At the very beginning of design, this thesis analyzes many micro-liquid samplingdevices in the market. Based on this analysis, the thesis improves these devices anddesigns completely the high-precision micro-liquid sampling device which can applyfor all kinds of Chemiluminescence’s analyzers, which includes the design ofmechanical structure, hardware system and software system. Besides, the thesis predictsthe precision of systematic sampling, analyzes the main error resources and the methodsfor reducing even eliminating these errors, which completes the design ofhigh-precision micro-liquid sampling device under the expectation of the precisiondemands.At first, in the mechanic device designing part, the author analyzes the mechanicdevices of which the current micro-liquid sampling devices changed electric machineryrotating into the injection rod linear motion in details and points out that there are geardrive and spiral drive these two traditional mechanical transmission devices. Throughcomparing the advantages and disadvantages of traditional devices and currentmicro-liquid sampling devices and based on the previous spiral drive devices, the authorcancels the mechanical reduction process and designs his sampling device.Then, in the control system part, the author divides it into the hardware andsoftware control parts. In the hardware control system designing section, the authordesigns the complete hardware system of micro-liquid sampling device finally throughthe chip selection, the control system scheme, the main control circuit, thecommunication interface circuit, the motor drive circuit and the line switch. In the software control system section, starting from the software control system andsubsystem, the author designs complete software system, which includes data sendingand receiving subsystem, the stepping motor control subsystem, the communicationinstruction set, the communication protocol, the speed controlling and the precisecontrolling.At last, the author introduces the main materials of high precision micro-liquidsampling device which it needs and explains the selection basis of the syringe, the threesolenoid values and the linear stepping motor and their respective parameters. Theauthor analyzes and handles the source of system error and based it the author lists5experimental programs, meanwhile, the author exams a large amount experiments andimproves the system. At the very end, the final test results prove that the system reachesthe predetermined precise target and meets the design requirements.