Software Design Of Liquid Rheological Property Testing Device Based On Rotation Method

Viscosity is an important index to measure the rheological properties of liquids. In many fields,such as petroleum, chemical, electric power, food and so on, it is very important to determine the viscosity and flow characteristics of fluids. Dielectric constant(also known as capacitance) is an important parameter to characterize the electrical properties of the material,and it is possible that the dielectric constant will change under the rotation of the fluid.At present, we can use viscometer alone to measure the viscosity of a fluid, can also use the dielectric spectrometer separately calculated the dielectric constant of the fluid.However, there is no means to measure the viscosity and the dielectric constant of the fluid at the same time.This paper introduces a rotating liquid rheological characteristics measurement device. The device realizes the combination of the viscometer and dielectric spectrometer, and it can simultaneously measure the viscosity value and the dielectric constant under the rotation of the fluid.We solve the problem of electrical signals transfer between the rotor and the container with the conductive ring, so as to realize the combination of the viscometer and dielectric spectrometer.The accuracy and stability of the fluid temperature in the container is very important when we measure the viscosity of the fluid by the device of viscosity measurement. Therefore, the device designed in this paper has the function of temperature measurement and control, which can keep the temperature in the container near the set value.This thesis studies a variety of temperature control algorithm. Combining the advantages of several algorithms, this paper designs a kind of improved fuzzy control algorithm based on pulse width modulation control. The algorithm combines the basic fuzzy control, human simulated intelligent control and improved bang-bang control algorithm,with the advantage of fast response, short transition time, small overshoot, small steady-state error, and so on.The stepper motor is an important part of the rotational viscosity detection device. Through the stepper motor, we can get accurate rotational speed,and the rotation speed is an important indicator of the rotational viscosity detection device for measuring viscosity. The stability and precision of rotational speed will directly affect the accuracy of the measurement of viscosity. However, when the stepper motor starts, it is easy to die, lose step and so on.Therefore, we study the design of several stepper motor start algorithm and we compare their effects, and finally we design theexponential type of stepper motor start algorithm, a good solution to the stepper motor start problem.Finally, we completed the design of the device, with the use of single-chip microcomputer as the main controller, and the design of the algorithm is applied to the program, to achieve the measurement of the liquid viscosity and dielectric constant at the same time at a certain temperature,and the results are displayed on the LCD screen in real time.