Method for automatically measuring and controlling forced vibration system
1 Principle of vibration measurement
The cantilever beam is forced to vibrate by excitation. The vibration signal can be converted into an electrical signal by the sensor. The weak signal is amplified to 0 to 5 V by the amplifier, and then the analog signal is converted to digital by the A / D converter. The signal enters the single-chip microcomputer for conversion processing, and the processing result is sent to the seven-segment digital display to show the acceleration value of the corresponding frequency.
The measurement principle of the vibration system is shown in Figure 1. The signal generator provides a periodic voltage signal to the exciter, which causes the exciter to generate periodic stimulus and excite the elastic beam. In this way, the elastic beam generates forced vibration. The acceleration sensor converts the vibration acceleration signal into an electrical signal.
2 Hardware interface design
(1) Hardware system block diagram
The hardware system block diagram is shown in Figure 2.
(2) Selection of acceleration sensor
According to the requirements of experimental data, GIA piezoelectric acceleration sensor is used.
The measuring range is 0.1g to 25g, and the frequency range is 0.5 to 500 Hz.
(3) Amplifier circuit
The amplifier circuit is shown in Figure 3.
Among them, C1 and R1 form a high-pass filter to eliminate the effects of DC components and temperature drift. A is a proportional amplifier. The amplification factor is determined by R2 and R3. R4 and C2 are used to filter out high-frequency noise.
(4) Analog-to-digital conversion circuit
The analog-to-digital conversion circuit is shown in Figure 4.
Select ADC0809 to complete this function. P2.7 ～ P2.5 of 8031 ​​in the figure are fully decoded by 74LS138. Because Y7 participates in the determination of ADC0809 port address, it is combined with the read / write signal of 8031 ​​via NOR gate. Make sure the address of ADC0809 is FFFFH.
(5) Static display interface circuit
The static display interface circuit is shown in Figure 5.
3 Software part
According to the hardware connection situation, the interruption method is used for the A / D conversion part, the data table is established according to the experimentally measured results, the table look-up method is used for the processing of the sampled data, and the serial output static display is used for the processing of the display part Program.
The flow of the main control program is shown in Figure 6, and the block diagram of the look-up table display program is shown in Figure 7.
4 Conclusion
The cantilever beam forced vibration automatic control system has a simple structure and convenient control, which improves the efficiency of the experiment and effectively overcomes the visual error. If it can be used in experimental teaching, it can play a good auxiliary role for the in-depth study of vibration laws.
Bitmain is the world's leading digital currency mining machine manufacturer. Its brand ANTMINER has maintained a long-term technological and market dominance in the industry, with customers covering more than 100 countries and regions. The company has subsidiaries in China, the United States, Singapore, Malaysia, Kazakhstan and other places.
Bitmain has a unique computing power efficiency ratio technology to provide the global blockchain network with outstanding computing power infrastructure and solutions. Since its establishment in 2013, ANTMINER BTC mining machine single computing power has increased by three orders of magnitude, while computing power efficiency ratio has decreased by two orders of magnitude. Bitmain's vision is to make the digital world a better place for mankind.
Bitmain Antminer:Bitmain Antminer KA3 (166Th),Bitmain Antminer L7 (9.5Gh),Bitmain Antminer Z15,Bitmain Antminer D7 (1286Gh),
Bitmain Antminer S19 XP (140Th),Bitmain Antminer E9 (2.4Gh),Bitmain Antminer Z11,Bitmain Antminer S3,Bitmain Antminer L3+ (504Mh)
Bitmain Antminer,S19 Pro Hyd 198T,antminer bitmain,antin s19j,antminer miner
Shenzhen YLHM Technology Co., Ltd. , https://www.hkcryptominer.com