CN2478196Y - Intelligent teaching test dynamic balancing machine - Google Patents

Abstract

The utility model discloses an intelligent teaching experiment dynamic balancing machine, which comprises two parts of an electric measuring box and a balancing machine body. Frequency multiplier circuit, pre-processor, tracking filter, AGC circuit, ADC circuit, etc. The body of the balancing machine is composed of a base, a pair of semi-rigid support swing frames, a motor, etc., with dynamic/static balance, hard/soft support Balance and many other setting functions, small size, safe and reliable to use, allowing students to operate by hand, through experiments to enable students to have a more complete and in-depth understanding of today's dynamic balancing technology.

Description

Intelligent teaching experiment dynamic balancing machine

The utility model relates to a digital teaching experiment equipment of microelectronic technology, in particular to an intelligent teaching dynamic balancing machine.

At present, the contradiction between domestic dynamic balance testing technical means and dynamic balance testing engineering requirements is prominent. On the one hand, the speed of various rotating machines is getting higher and higher, reaching tens of thousands or even hundreds of thousands of r/min. Supercritical or even super-second-order and third-order flexible rotors are common in engineering. Balance testing technology brings up many new topics. The low vibration and low noise indicators of industrial and household appliances require continuous improvement of dynamic balance accuracy. Light and small rotors such as military industry and textile machinery often only allow a few milligrams or even a few tenths of a milligram of residual unbalance. ; On the other hand, domestic dynamic balance testing techniques are still at the level of three dependencies: relying on obsolete equipment, relying on experience and exploration, and relying on imports. The equipment used in the dynamic balance experiment courses of mechanical, power, energy, electromechanical and other majors in various colleges and universities is either the original mechanical dynamic balancing machine or the general hard-supported industrial dynamic balancing machine. The former is obsolete and outdated and far from meeting the needs of teaching, while the latter has single function, high price, and high installation requirements, so it cannot be widely used in laboratories and can only be used for students to visit and demonstrate. A single hard support function is only suitable for balancing rigid rotors at low speeds. However, the balancing methods of high-speed, high-precision and supercritical rotors and on-site dynamic balancing methods that have been widely used in engineering today cannot be demonstrated to students through experiments, and of course they cannot be popularized. Let the students do hands-on operation to deepen their impression and understanding.

In view of the above problems, the purpose of this utility model is to design a dynamic balance measurement mode that can cover hard supports and can simulate high-speed and precise soft support measurement modes, and can independently perform on-site dynamic balance of rigid or flexible rotors, The dynamic balancing machine for intelligent teaching experiments with complete functions and low price is easy to teach and popularize, in order to enable students to have a more complete and in-depth understanding of today's dynamic balancing technology through experiments.

In order to achieve the above purpose, the technical solution adopted by the utility model is: organically combine microelectronic technology and mechanical technology, and design an intelligent teaching experiment dynamic balancing machine. This machine consists of two parts, the electric measuring box 1 and the body of the balancing machine. system, limiting shaping circuit, phase-locked frequency multiplication circuit, pre-processor, tracking filter, AGC circuit, ADC circuit connection, etc.; , switch buttons 8,9, and indicator light 10 are formed.

Another feature of the utility model is: the active pressure sensor sends the received signal to the pre-processor, and the processed signal is input to the tracking filter, and forms the left and right vibration signal channels with the AGC circuit; the photoelectric sensor inputs the signal Limiting shaping circuit, and phase-locking frequency multiplication circuit to form a reference signal channel; the vibration signal channel input ADC circuit is converted into digital quantities and input together with the signal reference channel. 89C51 single-chip microcomputer is the core, equipped with keyboard interface, extended ROM, RAM, and extended printing In the computer digital processing system of interface and LED display.

Because the utility model adopts the combination of microelectronics technology and mechanical technology, the most important feature is that A, B, and C dimensions of hard support dynamic balance can be realized without adjustment on a semi-rigid support frame. It can be solved by the influence coefficient method of soft support, which can be used for both dynamic balance correction and static balance correction. It has various functions required for dynamic balance teaching experiments. The intelligent design of software instead of hardware makes the cost of the balancing machine large. In order to reduce it, it is possible to popularize the teaching of dynamic balance experiments.

Fig. 1 is a structural diagram of the utility model;

Fig. 2 is a test system block diagram of the present utility model;

Fig. 3 is a schematic diagram of a vibration channel;

FIG. 4 is an electrical schematic diagram of a reference signal channel;

Fig. 5 is an electrical schematic diagram of a computer processing system;

Figure 6 is an electrical schematic diagram of the keyboard and display.

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

See Figure 1, Figure 2. A pair of semi-rigid support frames 3 are installed on the base 2 of the balancing machine body of the utility model, a pair of active piezoelectric force sensors 4 are installed on the semi-rigid support frames, a motor 5 and a photoelectric sensor 6 are fixed on the base 2, and a The damping base 7, the transmission belt of the motor 5 and the workpiece 11 to be tested are connected and placed on the hard support frame 3; the signals of the two active piezoelectric force sensors are connected to the input end of the limiter adjustment circuit on the electric measuring box 1, Its output end is connected to the input end of the pre-processing circuit, the output end of the pre-processing circuit is connected to the input end of the tracking filter, and its output end is connected to the input end of the AGC circuit to form left and right vibration signal channels; The signal is connected to the input end of the limit adjustment circuit, and the output end of the limit adjustment circuit is connected to the phase-locked frequency multiplication circuit to form a reference signal channel; the output ends of the two vibration signal channels enter the ADC circuit and are converted into digital quantities, and The signal reference channel is input together into the computer digital processing system with 89C51 single-chip microcomputer as the core, equipped with keyboard interface, extended ROM, RAM, extended printing interface and LED display.

See Figure 3. The operational amplifier U1 and its peripheral components R1-R5 and C1, C2 form a pre-transformation stage, which is used to convert the charge output from the sensor into a voltage. R1, R2 and R3 are connected into a T-shaped network, the purpose of which is to obtain a sufficiently large equivalent transmission impedance of the GΩ level from a low-value resistor to ensure the low-frequency response of the circuit and avoid noise and drift caused by the use of high-value resistors. The introduction of C2 can suppress the drift of the sensor output, and the circuit of this stage has a gain of 20dB.

U2A, U3 and peripheral components R6-R12 form an automatic gain control circuit (AGC), which is obviously a programmable gain amplifier in essence. At the moment of sampling, the CPU automatically judges the magnitude of the signal and sends a two-bit control instruction code to the circuit to change the gate terminal of 4051 and determine the access of R8, R9, R10 or R1, thereby automatically changing the gain of the circuit. The connection method of 4051 can ensure the passage of bipolar analog signals, and the two-bit control code can realize 4 kinds of gains. When sampling, the CPU writes a total of 4-bit gain codes to control the left and right channels respectively to ensure a suitable sampling level. U2B (the other half of TL072) is a foot follower circuit that buffers and isolates the output of U2A.

U4 is a MF10 single-chip integrated switched capacitor filter. This chip is a universal filter with multiple working modes, and is controlled by the clock signal CLK to realize tracking filtering. The connection method of MF10 and its external resistors R15-R22 makes this circuit work in the high-pass and low-pass combined mode, which composes a fourth-order band-pass filter to improve the signal-to-noise ratio, and completes the same frequency with the relevant filter module of the software Vibration component extraction. The vibration signal from the sensor is isolated and output by U5 after pre-processing, AGC circuit, and tracking filtering.

See Figure 4. U6, R28, R29, and R30 form a comparator circuit for shaping the reference signal from the photoelectric sensor. R26 and R27 determine the comparison threshold for power supply voltage division, and R32, R34 and D3 are used for limiting and signal polarity protection. The light-emitting tube D2 is a prompt for the comparator to work.

The integrated digital phase-locked loop 4046 (U7) 4040 (U8) constitutes a phase-locked frequency multiplication circuit. The external components R36, R33, C4 and C5 jointly determine the low-end frequency of the circuit. The output signal CLK is used as the working clock of MF10 on the one hand. On the other hand, it is input to the computer at the same time as the CLKA signal, and the software completes the speed measurement and phase measurement.

Fig. 5 is the principle circuit of the computer processing system, which is a single-chip microcomputer system composed of U9 (89C51) as the core. P00-P07 of U9 is the data bus of the system, the low 8-bit address of the system is latched by U10 (74LS373), and the high 8-bit address is P20-P27. The P1 port (lower 4 bits) of U9 is used as the AGC circuit control port, and the gain control is written by the entire byte of this port. The system expands a piece of ROM (U12 27256) and a piece of RAM (U11 6264). U13 (8155) is the keyboard interface. U14 (8255) is the A/D converter interface, the PA port of U14 is the data port, the PB port is used as the control port, PC0 is used for switching control of the left and right channels, and the left and right channels are time-sharing and full-period sampling.

U17 (74LS138) and U18 (74LS245) are display interface U17 decoding addresses A3 and A4 to form three strobe signals (DISCS1, DISCS2, DISCS3) used to strobe the three address segments of the display panel, and the lower three address A[0...2] collectively strobe each word bit and font code of the display panel are written by DD[0..7] after the data bus is buffered by U18.

U19A, U19B, R37, R38 and E1 form a reset circuit, and the manual reset is connected by RST to the reset key on the keyboard via socket CT-1.

U16B combines the 29th and 17th pins of U9 as a read signal. The system adopts ROM, RAM, and port unified addressing. The high three-bit address (A13, A14, A15) is decoded by U15 (74LS138) as a chip select signal. U16A combines the first four 8K addresses of U15 to form a 32K program address. The address allocation is: the program area occupies 000H-7FFFH, the display occupies 8000H-9FFFH, the keyboard interface occupies 0A000H-0BFFFH, and the RAM address is 0C000H-0DFFFH. The channel occupies 0E000H-0FFFFH.

The CLK and CLKA signals from the reference signal channel cooperate to complete the speed measurement, phase measurement, tracking filter control and synchronous full-cycle sampling.

The upper part of Figure 6 is the system connection diagram of the display; the lower right box is the drive control connection diagram of each display bit, and the common anode digital tube is driven by a 74F273 latch; the lower left part is the circuit of the keyboard.

The latch drive connections of the 21 seven-segment digital tubes are exactly the same, U19 is used to select the first 8 display digits, U20 is used to select the 9th to 16th display digits, and U21 is used to select the remaining 5 digits. It is directly written by the CPU on the bus DD[0..7]. All the information of measurement and operation are statically displayed by these 21 digital tubes, and their bit addresses are 8000H-8014H. Among them, 8000H-8003H and 8008H-800BH are respectively the left and right amplitude information segments, 8014H-8012H and 800EH-800CH are respectively the left and right phase information segments, 8004H-8007H are the rotational speed information segments, and 8011H-800FH are machine running status information part.

The 16-key keyboard is connected to the interface chip 8155 through the socket CT-1. Among them, SETUP and EXE are function keys, RESET is a control key, HALT and +/- are ping-pong keys, POINT/PRINT are multiple keys guided by a decimal point or an extensible printing interface, and the rest are number keys.

When the measured (workpiece) rotor 11 is dragged and rotated by the belt of the motor 5 on the balancing machine body, due to the central inertia of the rotor, the main shaft and its rotation axis are offset to generate unbalanced centrifugal force, forcing the semi-rigid support swinging frame to perform forced vibration. The two active power sensors installed on the semi-rigid support swing frame undergo electromechanical energy conversion by this force, and generate two electrical signal outputs containing unbalance information for the test system; at the same time, the photoelectric sensor installed near the rotor A reference signal with the same frequency and phase as the rotor rotation is also generated as a reference signal to be input into the test system. The switch buttons 8, 9 and indicator lights 10 arranged on the balancing machine body are used to display the working state of the balancing machine body.

After the test system receives the three-way signals, the hardware circuit performs pre-processing, tracking filtering, and amplitude adjustment to improve the signal-to-noise ratio and obtain a suitable level. With the support of the dynamic balance software package inside the test system, through squelch, amplitude and phase separation, correlation extraction, separation and calculation between correction surfaces, least square weighting processing, etc., finally calculate the unbalance of the left and right planes (grams) And correction angle (degrees), displayed by the digital tube, and at the same time give the measured speed (r/min).

The separation solution of the semi-rigid support mode is realized by using the A, B, C size algorithm of the rotor and the soft support mode influence coefficient solution algorithm, and the operation mode switching of the system parameters is set by commands in the shutdown state. Both soft and hard modes are carried out on the same hard support swing frame, and the support swing frame does not need to be replaced or adjusted when switching.

Claims (2)

1. An intelligent teaching experimental dynamic balancing machine, which consists of two parts: the electric measuring box [1] and the body of the balancing machine. It is characterized in that: the electric measuring box [1] is composed of a box body and a pair of Active piezoelectric force sensor [4], photoelectric sensor [6] and computer digital processing system, limiter shaping circuit, phase-locked frequency circuit, pre-processor, tracking filter, AGC circuit, ADC circuit, etc. are connected; The photoelectric sensor [6] sends the received signal to the limiting and shaping circuit, and then input it to the phase-locked frequency circuit after the limiting and shaping, and the phase-locked frequency multiplication circuit sends part of the signal to the computer digital processing system, and the other part to the tracking filter. It is also input into the computer digital processing system through the AGC circuit and ADC circuit; A pair of active piezoelectric force sensors [4] on the balance machine body are set at both ends of the workpiece to be measured, and the received signal is sent to the pre-processor, and the processed signal is input to the tracking filter and AGC circuit, and passed through the ADC The circuit is input into the computer digital processing system; The body of the balancing machine includes a base [2], on which a pair of semi-rigid support rocking frames [3] are fixed, and active piezoelectric force sensors [4] are installed on the pair of semi-rigid support rocking frames [3]. The hard support rocking frame [3] is used to place and support the workpiece to be tested, and the motor [5] is also fixed on the base [2]. Twist [8], [9], indicator light [10] and photoelectric sensor [6]. 2. The intelligent teaching dynamic balancing machine according to claim 1, characterized in that: the pair of active piezoelectric force sensors [4] sends the received signal to the pre-processor, and the processed signal input is tracked The filter and the AGC circuit together form the left and right vibration signal channels; the photoelectric sensor [6] inputs the signal into the amplitude limiting and shaping circuit, and forms the reference signal channel with the phase-locked frequency multiplication circuit; the vibration signal channel is input into the ADC circuit and converted into a digital quantity and a signal The reference channels are input together into the computer digital processing system with 89C51 single-chip microcomputer as the core, equipped with keyboard interface, extended ROM, RAM, extended printing interface and LED display.

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