Development Of An Automatic Monitoring System For Thermal Stability Test

Thermal Stability Test is to detect the chemical stability of raw materials for cables and wires,which are placed in the high-temperature oil bath environment,by monitoring the release rate of acid substances(according to the visual changes of the colour of the p H paper).The traditional test method is difficult to ensure the uniformity of discoloration recognition standards by naked eye observation.Moreover,the exact discoloration time point of the p H paper will not be recorded accurately,resulting in poor reproducibility and traceability.In order to monitor the whole test efficiently,properly and accurately,this dissertation intends to develop an automatic monitoring device for the thermal stability test based on a machine vision module and a single-chip microcomputer system.Firstly,considering the testing procedures and problems of the thermal stability test,in this dissertation,the basic functions and procedures of the automatic monitoring system are conceived,in which functional modules such as the serial port touch screen,the machine vision module and 3-DOF steering manipulator arm are selected,the structure diagram of the automatic monitoring system is designed according to the specific purpose and operation method of the function modules,the main-subsystem structure is adopted to ensure the functional stability of the single-chip microcomputer,3Dsmax software is applied to draw the system model,and the interconnection structure and connection mode of each module are determined on the basis of the model.Secondly,this dissertation teaches to design and develop the thermal stability automatic monitoring system from the main controller,the machine vision module,the mechanical sub-system and other auxiliary systems.The main controller is designed to select a STM32 single-chip microcomputer as the core to implement configuration and programming of the man-machine interface USART HMI by C Language programming to meet the functional needs of information input and visual display.With the clock module DS3231 and SD card module,the function of time data acquisition and result recording is realized.With regard to the vision module,it programs the K210 module by using python Language,determines the target color threshold range through LAB color threshold method,identifies the target color area by using the maximum color block,and ensures the recognition effect of the machine vision module by using the histogram equalization pre-processing algorithm.As to the sub-controller,it presents a design of the interface and the program,and sends the control instructions through the 16-way steering gear controller.On account of the thick oil mist conditions,tan anti-oil mist device is designed to ensure the camera lens that can be kept clean for a long time,and a small system based on the wireless LORA module is also designed to realize the function of sending and receiving wireless alarm data.Finally,in this dissertation,the resultant monitoring system,subject to debugging and validation,achieves the functions like automatic monitoring,data recording and alarm warning of the thermal stability test.The research and development results of this dissertation have solved the practical problems in the current thermal stability test,and improved the work efficiency and the test quality.It also provides a reference for other applicable quality inspection test items of cables and wires.