Intelligent displacement meter multi-point calibration device and calibration method

Abstract

According to the intelligent displacement meter multi-point calibration device and calibration method, the calibration operation process can be simplified through carrying of a plurality of adjustable contact blocks and a plurality of displacement meter fixing devices, calibration of a plurality of displacement meters is carried out at the same time, the calibration efficiency is greatly improved, and the calibration precision is improved. Corresponding displacement and electric signal data are accurately input and read through computer programming, and finally a calibration coefficient is output, so that the accuracy is improved, and intelligentization is realized.

Description

Technical Field

[0001] The present invention relates to the field of instruments and meters, in particular to an intelligent displacement meter multi-point calibration device and a calibration method. Background Art

[0002] In water conservancy and hydropower projects, rock mass displacement is an important index for evaluating the stability of rock masses. The cost of in-situ experiments in actual projects is high and time-consuming. Only a small number of tests can be carried out according to the actual project requirements, which cannot fully meet the research needs. Therefore, laboratory physical similarity model experiments are often required to provide a basis for on-site actual research. Under a small-scale experimental model, accurately obtaining the displacement change of surrounding rock is an important issue. Currently, the most commonly used method is to measure the corresponding displacement by arranging internal and external displacement meters in the laboratory similarity model.

[0003] In order to accurately measure the displacement of the rock mass, before each displacement meter is buried, it is necessary to detect and calibrate the displacement meter, and directly establish the connection between the displacement meter value and the measured electrical signal through calibration. The traditional calibration device basically completely relies on manual operations such as the placement of displacement meters and data reading. The number of displacement meters required for one experiment may be hundreds or thousands. This not only consumes manpower and time, but also may have human errors, which is not conducive to the development of model tests.

[0004] CN105783688A provides a displacement meter servo calibration system, but the calibration efficiency of this solution is low. It can only calibrate one displacement meter at a time, and its contact block is fixed, making it difficult to adjust the contact with the displacement meter and inconvenient to operate. At the same time, the intelligent processing of the calibration data in this solution is relatively low. It is necessary to operate the servo motor separately. After pushing the movable frame, then use the grating displacement sensor to sense the displacement and input it into NI, and the operation process is complex. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an intelligent displacement meter multi-point calibration device and a calibration method in view of the deficiencies of the prior art, which can perform simultaneous calibration of several displacement meters and improve the calibration efficiency.

[0006] To solve the above technical problem, the technical solution adopted by the present invention is: an intelligent displacement meter multi-point calibration device, comprising:

[0007] A fixed frame;

[0008] A servo motor, arranged on one side of the fixed frame;

[0009] A lead screw, one end of which is connected to the output shaft of the servo motor, and the other end is connected to the middle part of the movable frame;

[0010] A number of adjustable touch blocks are arranged on the movable frame along the height direction of the movable frame, and when the movable frame moves along the fixed frame, the adjustable touch blocks can contact the free end of the displacement gauge;

[0011] A number of displacement gauges are arranged on the fixing device along the height direction of the fixing device, and are arranged opposite to the number of adjustable touch blocks, and the fixing device is fixed on the fixed frame.

[0012] By using the calibration device of the present invention, a number of displacement gauges can be calibrated simultaneously, greatly improving the calibration efficiency. The touch block of the present invention can move with the movable frame, facilitating contact with the displacement gauge and having simple operation.

[0013] The adjustable touch block includes a chute and a touch block. The upper part of the chute is open, and one end of the touch block straddles both sides of the upper opening of the chute. The adjustable touch block of the present invention has a simple structure.

[0014] A locking nut is arranged on the touch block. One end of the locking nut passes through the touch block and is placed in the opening of the chute. The touch block can be tightened by the locking nut, so as to facilitate the cooperation between the displacement gauge and the touch block.

[0015] The fixing device includes a body. A first card slot for fixing the displacement gauge is opened in the middle of the body, and a pin slot is arranged on one side of the first card slot away from the body.

[0016] A fixing nut is arranged at one end of the pin slot away from the body. It is convenient to clamp the displacement gauge.

[0017] A second card slot for placing a pressure box is also opened in the middle of the body. The pressure box is provided in the present invention, which can measure the fixing degree of the displacement gauge. By first testing the pressure value when a displacement gauge is fixed stably, all subsequent displacement gauges can be quickly locked according to this pressure value during installation.

[0018] The center point of the pressure box and the center point of the body are located at the same horizontal height. Since the fixing nut is aligned with the middle of the body when the displacement gauge is fixed, in order to ensure the accuracy of the pressure measured by the pressure box, the middle of the pressure box and the middle of the body are arranged at the same height.

[0019] The displacement gauge is connected to a data acquisition device, and both the servo motor and the data acquisition device are connected to a processor.

[0020] As an inventive concept, the present invention also provides a method for calibration using the above intelligent displacement gauge multi-point calibration device, including the following steps:

[0021] S1. Set the speed and travel length of the servo motor;

[0022] S2. Determine whether the total number of output pulses of the servo motor reaches the maximum number of pulses corresponding to the set walking length. If not, continue to output the number of pulses in the next cycle until all the total number of pulses is output; if so, control the motor to rotate in the reverse direction for reset; where the total number of pulses = the set value of the walking length * the number of pulses required for each revolution of the motor.

[0023] In the present invention, the walking length = the maximum set length / T, where T is the number of cycles, and the maximum set length does not exceed the maximum displacement value of the displacement gauge.

[0024] Preferably, to improve the calibration accuracy, the number of cycles is not less than 5 times.

[0025] Preferably, there is an interval of 30 s between two adjacent cycles to further improve the calibration accuracy.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. By controlling the rotation of the servo motor, high-precision and high-efficiency fixed-point displacement can be achieved, and the fitting result is more accurate.

[0028] 2. The displacement and electrical signal data are collected and fitted by the computer terminal simultaneously, realizing intelligence.

[0029] 3. The calibration device is equipped with a displacement gauge fixing device and an adjustable touch block, and it is more convenient and faster to install the displacement gauge and make the touch block contact the displacement gauge, saving time.

[0030] 4. A number of displacement gauges can be calibrated simultaneously, greatly improving the calibration efficiency. Description of the Drawings

[0031] Figure 1 It is a top view of the intelligent displacement gauge multi-point calibration device according to an embodiment of the present invention;

[0032] Figure 2 is Figure 1 the front view of the intelligent displacement gauge multi-point calibration device in

[0033] Figure 3 is Figure 1 the left view of the intelligent displacement gauge multi-point calibration device in

[0034] Figure 4 is Figure 1 the right view of the intelligent displacement gauge multi-point calibration device in

[0035] Figure 5 is Figure 1 the front view of the adjustable touch block in

[0036] Figure 6 is Figure 1Top view of the adjustable touch block in

[0037] Figure 7 is Figure 1 Front view of the displacement gauge fixing device in

[0038] Figure 8 is Figure 1 Left view of the displacement gauge fixing device in

[0039] Figure 9 PLC control servo motor flowchart of the intelligent displacement gauge multi - point calibration system of the embodiment of the present invention;

[0040] Figure 10 PLC program diagram of the embodiment of the intelligent displacement gauge multi - point calibration system of the embodiment of the present invention;

[0041] Figure 11 Flowchart of the usage method of the intelligent displacement gauge multi - point calibration device of the embodiment of the present invention.

[0042] Reference numerals:

[0043] 1 - Servo motor; 2 - Lead screw; 3 - Movable frame; 4 - Adjustable touch block; 5 - Displacement gauge fixing device; 6 - Displacement gauge; 41 - Chute; 42 - Touch block; 43 - Locking nut; 51 - Fixed nut; 52 - Displacement gauge placement slot; 53 - Pressure box placement slot; 54 - Pressure box; 7 - NI data acquisition board; 8 - Labview; 9 - Fixed frame. Detailed implementation manners

[0044] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] Embodiment 1

[0046] This embodiment provides an intelligent displacement gauge multi - point calibration device, as Figures 1 to 8 shown.

[0047] As Figure 1As shown in the figure, an intelligent displacement meter multi-point calibration device according to an embodiment of the first aspect of the present invention includes a servo motor 1 fixed on the left side of a fixed frame 9. One end of a lead screw 2 is connected to the driving device of the servo motor 1, and the other end of the lead screw 2 is connected to the middle part of a movable frame 3 through a threaded hole. Both ends of the movable frame 3 are connected to the fixed frame 9 by two connecting rods. A number of adjustable contact blocks 4 are fixed on the movable frame. The position of the contact block 4 can be adjusted to contact a displacement meter 6. The displacement meter 6 is fixed by a displacement meter fixing device 5. A number of displacement meter fixing devices 5 are fixed on the right side of the fixed frame 9. The displacement meter 6 is connected to a data acquisition board 7 (data acquisition device) through a wire. The servo motor 1 and the NI data acquisition board are respectively connected to Labview 8 through wires. The servo motor encoder connector is connected to Labview, which has a built-in PDA system and uses a PLC control program to control the servo motor. The PDA reflects the status and data of the PLC system on the interface in real time through the WCS management control system and provides a manual debugging interface for the PLC system and the production line. After receiving the instructions from the WMS system, the WCS management control system sends them to the PLC system, thereby driving the servo motor to rotate accordingly. The movable frame is lapped on the fixed frame and is pushed by the rotation of the servo motor for fixed-point displacement. The fixed-point displacement amount is recorded by Labview. Labview outputs the recorded electrical signal data. Labview also has a built-in calibration fitting program to fit the obtained displacement-electrical signal (strain) data and output the calibration coefficient. Calibration coefficient = displacement / electrical signal (strain).

[0048] Specifically, as Figures 2 to 4 shown, a number of adjustable contact blocks 4 can be fixed on the upper part of the movable frame 3, and a number of displacement meter fixing devices 5 can also be arranged at the rear of the fixed frame 9. The displacement meter fixing device 5 is lower than the corresponding adjustable contact block 4 (the displacement meter fixing device is used to fix the lower part of the displacement meter so that the strain gauge on the upper part of the displacement meter contacts the contact block). The two are arranged opposite to each other to ensure that the strain gauge of the installed displacement meter is horizontal with the middle part of the adjustable contact block..

[0049] As Figure 5 、 Figure 6 shown, the chute 41 (sliding chute) is in the shape of a flat cuboid, hollow inside and open at the upper part. The middle part of the contact block 42 is hollowed out. The contact block 42 straddles the chute 41. The locking nut 43 bolts are placed inside the chute 41. The bolts pass through the chute 41 and the contact block 42 together. Tightening the nut can lock the contact block 42. The adjustable contact block is fixed on the movable frame. The chute is fixed on the movable frame and cannot move. The contact block can slide straddling the chute. After adjusting to ensure good contact between the contact block and the fixed displacement meter, lock the contact block with the locking nut, so that the displacement meter and the contact block act together. The contact surface of the contact block should have a certain hardness and be smooth. A number of adjustable contact blocks can be arranged on the movable frame at the same time.

[0050] As Figure 7 、 Figure 8As shown, the middle part of the main body of the displacement meter fixing device 5 has a square card slot 52 (the first card slot) for placing the displacement meter 6. The upper and lower parts are open to facilitate the placement of the displacement meter 6 and the connecting wire. The length and height of the card slot 52 do not exceed 1.5 cm. A circular nut pin slot is provided on one side of the front of the card slot. The fixing nut 51 rotates to firmly fix the displacement meter placed inside. The middle part of the displacement meter fixing device 5 also has a placement card slot 53 (the second card slot) for placing the pressure box 54. The pressure box 54 is fixed to the pressure box card slot with double-sided tape. The middle part of the pressure box 54 is directly opposite to the middle part of the displacement meter fixing device 5. The upper part of the card slot for placing the pressure box is open to facilitate the placement of the pressure box, and the lower part is closed and oval-shaped to facilitate the support and fixation of the pressure box. The length and height of the card slot do not exceed 3 cm.

[0051] Figures 9 to 10 This is the intelligent displacement meter multi-point calibration system according to the embodiment of the present invention.

[0052] In some embodiments, the servo motor adopts a PDA system. The servo motor encoder connector is connected to Labview, with a built-in PDA control system. The PLC is used to control the servo motor program. The PDA reflects the status and data of the PLC system on the interface in real time through the WCS management control system and provides a manual debugging interface for the PLC system and the production line. After receiving the instructions from the WMS system, the WCS management control system sends them to the PLC control system, thereby driving the servo motor to generate corresponding rotations.

[0053] In some embodiments, the principle of the PLC control system is as follows:

[0054] The servo motor is set to rotate one circle for every 1000 pulses. The set walking length unit is 1 μm. The walking length of the servo motor for each rotation is 1 mm. The number of pulses required for the servo motor to rotate one circle is 1000. Therefore, the walking length for each pulse sent by the PLC is 0.001 mm. Then the PLC output pulse number = length setting value * 1000. The maximum displacement for the displacement meter calibration is 3 mm. The corresponding relationship list between the pulse number and the displacement is as follows:

[0055]

[0056] The required motor speed is 1200 revolutions per minute. The PLC output pulse frequency = (speed setting value / 6) * 100 HZ. Therefore, the PLC should send out a pulse frequency of 20k, and the corresponding CPU of the PLC needs to be greater than this threshold. According to the above requirements for accuracy and speed, the electronic gear ratio of the servo motor is set.

[0057] In some embodiments, the operation process of the PDA system is as follows:

[0058] Start x0 through the PDA system, set the motor speed to 1200 revolutions per minute, and the walking length to 3 mm. First, for the first time, the output frequency is 20000, the number of output pulses is 500, send the pulse signal to the output terminal y0, display that the current total number of pulses is 500, and the interval time is 30 s. Then, for the second time, the output frequency is 20000, the number of output pulses is 500, send the pulse signal to the output terminal y0, display that the current total number of pulses is 1000, and then the interval time is 30 s. Repeat this form 4 more times. At this time, the total number of pulses output by the servo motor is 3000, walking 0.5 mm each time in six times, and walking a total of 3 mm, thus intelligently realizing the precise displacement of the lead screw of the calibration device.

[0059] As Figure 10 shown, the intelligent displacement gauge multi-point calibration system of the embodiment of the present invention includes a servo motor PLC control program and a displacement-electric signal fitting calibration program.

[0060] In some embodiments, the PLC control program is as follows:

[0061] Program the PLC program according to the actual calibration requirements of the displacement gauge. First, set the start instruction x0, set the speed and walking length of the servo motor, then output the corresponding sub-frequency s1 and the number of output pulses s2 through the PLSY instruction, and send this instruction to the output address terminal y0, and display the current total number of pulses. Then, judge whether the total number of output pulses has reached the maximum number of pulses set to meet the set length. If not, continue to output the number of pulses in the next cycle. There should be an interval of 30 s between two cycles until all the total number of pulses is output; if satisfied, close the start instruction x0, then set a new start instruction x1, output the total number of pulses s2 through the PLSY instruction, and finally send this instruction to the output address terminal y3 to make the motor rotate in reverse to reset.

[0062] In some embodiments, the displacement-electric signal (strain) fitting calibration program is to linearly fit the strain value and the corresponding displacement value using the least squares method (see CN105783688A for reference).

[0063] Embodiment 2

[0064] This embodiment provides a method for using the calibration device of Embodiment 1, that is, a method for calibration using the calibration device of Embodiment 1.

[0065] As Figure 11 shown, in some embodiments, the method for using the intelligent displacement gauge multi-point calibration device specifically includes the following steps:

[0066] S1: Fix the pressure cell 54.

[0067] Paste double-sided tape on the back of the pressure cell, place the pressure cell into the pressure cell installation slot, with the bottom of the pressure cell touching the bottom of the slot. Press and paste the pressure cell on the pressure cell slot with your finger through the displacement gauge installation slot, ensuring that the pressure cell cannot rotate left and right or slide up and down, and the middle of the pressure cell is directly opposite the center of the displacement gauge fixing device.

[0068] S2: Fix the displacement gauge 6.

[0069] First, pre-press the displacement gauge and measure the pre-press strength value of the displacement gauge. Connect the wires of multiple displacement gauges to be calibrated to the strain acquisition instrument, and then place the displacement gauges together with the wires into the limit square holes of the displacement gauge fixing device, ensuring that the circular contacts at the top of each displacement gauge can be in parallel contact with the middle of the contact block of the movable frame. Then insert the fastening nut into the pin hole and tighten it until the pressure cell reaches the pre-press strength value and stop, ensuring that the displacement gauge cannot rotate left and right or slide up and down. When fixing other displacement gauges, just tighten the nut until the strength of the pressure cell reaches the pre-press strength value.

[0070] S3: Adjust the positions of the displacement gauge 6 and the contact block 42.

[0071] When conducting the initial calibration, the position of the contact block needs to be adjusted. Use Labview to control the servo motor to push the movable frame forward. Stop the servo motor when the contact block is roughly in contact with the displacement gauge. Make fine adjustments through the touch block device to ensure good contact between the middle of the contact block and the circular contacts at the top of each displacement gauge. After contact, zero the displacement of the displacement gauge on the computer.

[0072] S4: The servo motor PDA system adjusts the working parameters of the servo motor 1.

[0073] Connect the servo motor to Labview. Adjust the output parameters of the PLC control program in the built-in PDA system according to the actual displacement calibration requirements. The maximum set length cannot exceed the maximum displacement value of the displacement gauge. Divide the maximum set length into several equal-length parts for calibration, and the number of calibrations shall not be less than 5 times; Start the PDA forward working button, set the motor speed, based on the actual motor parameters; Output the number of pulses per time, the number of pulses per output = the length of each equal-length part * the number of pulses required for the motor to rotate one circle; Output the pulse frequency, pulse frequency = (speed set value / 6) * 100HZ.

[0074] S5: The PDA system controls the operation of the servo motor 1.

[0075] The PDA system outputs pulses to the servo motor. The servo motor rotates forward to drive the calibration device to work. Perform cyclic operations according to the divided number of times. Output the same number of pulses each time, with an interval of 30s between each operation until the maximum travel length is completed.

[0076] S6: The computer terminal Labview8 collects data and fits.

[0077] After each fixed-point displacement of the servo motor, the displacement amount is the displacement value of the displacement gauge, which is recorded and displayed by the computer terminal Labview; after each displacement gauge is deformed, corresponding electrical signal data is generated, and is collected and displayed by Labview through wires. After the maximum walking length is completed, the displacement and electrical signal data of each group are fitted to obtain and output the calibration coefficient.

[0078] S7: Reset servo motor 1.

[0079] Start the reverse working button of the PDA system, output the total number of pulses, total number of pulses = length set value * number of pulses required per revolution of the motor; output the pulse frequency, pulse frequency = (speed set value / 6) * 100HZ; the PDA system outputs the pulses to the servo motor, and the servo motor rotates in reverse to pull the calibration device to reset; after the displacement gauge calibration is completed, proceed to the calibration process of the next group of displacement gauges.

[0080] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0081] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. An intelligent displacement meter multi-point calibration device, characterized in that: include: Fixed frame; A servo motor is arranged on one side of the fixing frame; A screw rod, one end of which is connected to the output shaft of the servo motor, and the other end of which is connected to the middle part of the movable frame; A plurality of adjustable contact blocks are arranged on the movable frame along the height direction of the movable frame, and when the movable frame moves along the fixed frame, the adjustable contact blocks can contact the free end of the displacement meter; A plurality of displacement meters are arranged on the fixing device along the height direction of the fixing device and are arranged opposite to the plurality of adjustable contact blocks. The fixing device is fixed on a fixing frame.

2. The intelligent displacement meter multi-point calibration device according to claim 1 is characterized in that: The adjustable contact block comprises a slide slot and a contact block. The slide slot has an upper opening, and one end of the contact block is connected across two sides of the upper opening of the slide slot.

3. The intelligent displacement meter multi-point calibration device according to claim 2 is characterized in that: A tightening nut is arranged on the contact block, and one end of the tightening nut passes through the contact block and is placed in the opening of the slide slot.

4. The intelligent displacement meter multi-point calibration device according to claim 1 is characterized in that: The fixing device comprises a body, a first slot for fixing the displacement meter is provided in the middle of the body, and a pin slot is provided on a side of the first slot away from the body.

5. The intelligent displacement meter multi-point calibration device according to claim 4 is characterized in that: A fixing nut is arranged at one end of the pin slot away from the body.

6. The intelligent displacement meter multi-point calibration device according to claim 4 is characterized in that: The middle part of the main body is also provided with a second slot for placing the pressure box.

7. The intelligent displacement meter multi-point calibration device according to claim 6 is characterized in that: The center point of the pressure box and the center point of the body are located at the same horizontal height.

8. The intelligent displacement meter multi-point calibration device according to any one of claims 1 to 7, characterized in that: The displacement meter is connected to a data acquisition device, and the servo motor and the data acquisition device are both connected to a processor.

9. A method for implementing calibration using the intelligent displacement meter multi-point calibration device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, set the speed and travel length of the servo motor; S2. Determine whether the total number of output pulses of the servo motor has reached the maximum number of pulses corresponding to the set walking length. If not, continue to output the number of pulses for the next cycle until all the total number of pulses are output; if so, control the motor to rotate in the opposite direction and reset; where the total number of pulses = the set walking length * the number of pulses required for the motor to rotate one circle.

10. The method according to claim 9, characterized in that The walking length = maximum set length / T, T is the number of cycles, and the maximum set length does not exceed the maximum displacement value of the displacement meter; preferably, the number of cycles is not less than 5 times; preferably, the interval between two adjacent cycles is 30s.

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