| With the development of industry all over the world,the speed sensor has become an important support for the development of modern industrial automation.It plays a great role in automobile,machinery manufacturing and aerospace,widely used in numerically controlled machine tool,cutting laser machines,as well as industrial transmission and other mechanical equipment.Based on the existing speed sensors,a speed sensor based on triboelectric nanogenerator is proposed.The triboelectric nanogenerator is installed in the rotating device.The rotation of the device drives the rotation of the triboelectric nanogenerator.The sine wave signal is transmitted to the signal processing circuit,and the sine signal can be converted into the square wave signal with the same frequency after the circuit processing conversion.The square wave signal is transmitted to the single chip microcomputer to read the pulse frequency of the square wave,which is calculated through the formula in the program written in advance in the single chip microcomputer.The serial port is used to display the speed of the device.The specific work is as follows:(1)The model of triboelectric nanogenerator prototype is studied.Based on electrostatic induction and charge transfer mechanism,the independent layer type of friction nanogenerator is determined on the basis of Maxwell equations,and the prototype model is established by using Solid Works 3D drawing software,and the generation principle of the prototype is introduced in detail By using COMSOL software,the physical static field steady-state simulation analysis of triboelectric nanogenerator is carried out,and the distribution of generating charge is visually displayed,which provides theoretical guidance for the output of triboelectric nanogenerator signal.(2)Carry out the theoretical analysis and design of signal waveform processing system.The LM324 operational amplifier chip is selected as the core component of signal processing circuit,and the circuit simulation test is carried out by using Multisim software.The sinusoidal signal output by triboelectric nanogenerator is compared with the square wave signal after circuit processing,and the frequency consistency of the two waveform is verified.Thus,the corresponding speed can be correctly calculated according to the frequency.The smaller the frequency error,the more beneficial to reduce the error rate of the sensor.And a partial voltage resistor is used to reduce the voltage of the output signal to ensure the stability of the single chip microcomputer reading signal.At the back end of the circuit,STM32 single chip microcomputer is used as the core of signal processing.The program is written to read the frequency of square wave and input the formula to convert the frequency and speed.The speed value of corresponding waveform frequency is output through the serial port.It provides a theoretical basis for the feasibility of the experiment.(3)The basic output characteristics of triboelectric nanogenerator speed sensor were tested.Based on virtual instrument technology,the rotating shaft of triboelectric nanogenerator and the rotating shaft of experimental motor are connected by coupling,and the experimental circuit is built at the back end.The input sine wave signal is converted into square wave signal,which is transmitted to the single chip microcomputer for reading and analysis.Finally,the serial port is connected to display the speed in real time.The whole system test platform is built with the above components,and the experimental system is tested.The durability test of the whole test system is carried out after continuous operation for 6 hours,and the results show that the output sine wave signal attenuates by 3.8%.The error rate of the triboelectric nanogenerator speed sensor is analysed,and the error rate of the whole system test is controlled within 1.9%. |
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