Research On Key Technology Of Sample Transfer Machine Of LCT Producer

Cervical cancer, one of the most common malignant tumors in women, happen all over the world. In order to control the rate of cervical cancer, the most-frequently-used measure is to start early screening. And sedimentary Liquid-based cytology technology (LCT) is one of the most effective mans.As an important component of sedimentary Liquid based cell preparation(LBP), sample transfer machine plays a critical role in the quality of the cell preparation. In fact, sample transfer machine take the place of artificial transferring which can save work force and avoid diagnosis cell loss by human error to reach unification and automation of the production.High accurate controlling and flexible Preferences settings of the stepper motor is necessary to transfer the sample from the specimen jar to the centrifugal tube quantificational and slowly.According to the requirements of sample transfer machine, we design a stepping motor control system based on MCU,then the control method of rising and reducing speeds of the stepped motor is analyzed; the paper also design an human-machine interface system for setting various parameters in the stepping motor control system; finally,I adopt grating sensor to track and measure the displacement size of the stepping motor to provide evaluation of the designed stepping motor.The main research contents as follows:(1) Describe the study state of the sedimentary LBP Liquid based cell preparation machine, put forward the background,meaning and main contents of this research project.(2) The design of Stepping motor control system based on MCU C8051F020. The paper study the automatic control methods to design an software programming by which MCU C8051F020 system can output pulse sequence in a frequency range to control the stepper motor operation by subdivided driving; to control Running direction by high and low levels of alternating sequence; to output different clock-pulse frequency by timer interrupt, and then control rising and reducing speeds of the stepping motor.(3) The design of human machine interface. Control system centering on MCU C8051F020 utilize touch bottom and LCD(Liquid Crystal Display) etc to realize human-machine interaction operation. The user can know the state information of the prototype shown on the interface, and conduct a series of operations by the touch bottoms. The interface is simple and convenient. (4) The design of rising and reducing speed curve of Stepping motor. In this part, the paper respectively introduce three methods:based on kinematic equation to get needed parameters directly of rising and reducing speeds curve of the stepping motor,discretization method of rising and reducing speeds curve of the stepping motor and fitting method of rising and reducing speeds curve of the stepping motor. Then we use MATLAB to simulate liner and exponential type control algorithm in the discretization of rising and reducing speeds curve of the stepping motor, and we also have theoretical analysis to test them.(5) The experiment and results analysis. In order to verify the correctness of the above theory analysis, we use grating sensor, targeting displacement accuracy of the sample transfer machine to laboratory tests. Base on the actual displacement size range 0-50cm, Through the analysis of experimental results, the linear rising and reducing speed control methods is very fast in accelerating phase and mutations is also very fast in accelerating period with uniform section interchange to make sample transfer machine concussion easily, but the sports displacement is very short about 0.33 cm in rising and reducing speed time. Relatively, exponential type control algorithm is much slower. It's also smooth at the intersection of the end of acceleration stage and constant speed stage. The sports displacement in rising and reducing speed time is longer about 13 cm. But for index motion control algorithm it can't reach the requirement, if the sports displacement is less than 13 cm. Therefore, combining the two rising and reducing speed control methods to realize the operating of the sample transfer. When we validating it by experiment, we found the result is very ideal and the movement process of manipulator is more stable. And compared with the theoretical data, the sports displacement accuracy only have a discrepancy in 0.0427mm(the average of the three times), manipulator 0.668cm, specimen jar 1.67cm, we believe the error have no influence in the results.