High-precision linear displacement sensor automatic calibration device and method

Abstract

In order to solve the technical problems of time-consuming and labor-consuming in manual calibration of pull rod type linear displacement sensor by traditional high-precision vernier caliper or depth gauge, the present application provides a high-precision linear displacement sensor automatic calibration device and method, the present application adopts high-precision motor as power, designs special calibration platform, designs special calibration platform, through the cooperation of linear motion mechanism and zero adjustment mechanism, realizes the batch of coarse zero adjustment, the automation and batch of calibration in displacement calibration, eliminates the error generated by forward and reverse stroke cyclic calibration and the unreliable factors in manual calibration operation, greatly improves the calibration quality and calibration efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-precision linear displacement sensor calibration device, for the batch calibration of linear displacement sensor, with the characteristics of high efficiency, high precision, can be widely applied in solid rocket engine ground ignition test, solid rocket engine structural strength test field. BACKGROUND

[0002] In the process of solid rocket engine research and test, a series of tests need to be carried out to verify the structure of the engine and evaluate the performance of the engine. Displacement measurement is a basic test item in the process of solid rocket engine test, which is of great significance to evaluate the macroscopic deformation of the engine in the test process and evaluate the stiffness and strength of the engine. Due to the particularity of solid rocket engine displacement measurement, it has more displacement measurement points and higher test data quality requirements than general engineering tests. The displacement sensor used in solid rocket engine test is of various types, among which the pull rod type linear displacement sensor is the most important type of displacement sensor used in engine test.

[0003] Displacement sensor calibration is an important link for high-quality application of displacement sensor and a necessary means to improve the quality of displacement test data. The pull rod type linear displacement sensor used in current solid rocket engine test is manually calibrated by high-precision vernier caliper or depth gauge. In the actual calibration process, there is a problem of difficult operation in the forward and reverse stroke cycle calibration. The whole calibration process is time-consuming and labor-intensive, with low calibration efficiency and poor calibration quality, which seriously consumes a lot of test time and resources.

[0004] OBJECTIVE

[0005] In order to solve the technical problems of time-consuming and labor-intensive in the calibration of pull rod type linear displacement sensor by traditional manual calibration method with high-precision vernier caliper or depth gauge, the present application provides a kind of high-precision linear displacement sensor automatic calibration device and method, which can improve the calibration efficiency and quality of displacement sensor and save test resources to meet the needs of test development.

[0006] The technical scheme of the present application is:

[0007] A kind of high-precision linear displacement sensor automatic calibration device, its special features are: including machine case, linear motion mechanism, zero adjustment mechanism, calibration target fixing mechanism, drive unit, control unit and man-machine interaction unit arranged in the machine case;

[0008] The zero adjustment mechanism is arranged on the linear motion mechanism, and is driven by the linear motion mechanism to move linearly, to realize the batch coarse adjustment of the linear displacement sensor to be calibrated and calibration;

[0009] The zero adjustment mechanism is used to realize the individual fine adjustment of the zero of the linear displacement sensor to be calibrated.

[0010] The calibration target fixing mechanism is used to fix the linear displacement sensor to be calibrated on the cabinet.

[0011] The control unit is used to receive the data of the human-computer interaction unit and issue pulse instructions and direction instructions for controlling the linear motion mechanism and the zero adjustment mechanism to the driving unit.

[0012] The human-computer interaction unit is used to realize the input and display of parameters.

[0013] Further, the linear motion mechanism comprises a high-precision motor, a linear slide rail platform, a linear slide rail and a grating ruler; the linear slide rail platform is arranged on the linear slide rail and is driven by the high-precision motor to move along the linear slide rail; and the grating ruler is arranged on the mounting base of the linear slide rail.

[0014] Further, the zero adjustment mechanism comprises a zero adjustment button, a plurality of driving circuits and a plurality of electric push rods; the electric push rods are arranged on the linear slide rail platform and coaxially arranged one by one corresponding to each linear displacement sensor to be calibrated.

[0015] Further, the end of the electric push rod is provided with an electric push rod top disc.

[0016] Further, the calibration target fixing mechanism comprises a mounting channel for accommodating the linear displacement sensor to be calibrated, a displacement front limit arranged at the front end of the mounting channel, a channel rear limit arranged at the rear end of the displacement channel and a top screw; the mounting channel, the displacement front limit and the channel rear limit are clamped as a whole on the displacement fixing frame and are installed on the cabinet through the displacement fixing frame.

[0017] Further, the cabinet is provided with an observation window.

[0018] The method for calibrating the linear displacement sensor by using the high-precision linear displacement sensor automatic calibration device as claimed in the claim comprises the following steps:

[0019] Step 1: power on, pass the displacement sensor to be calibrated through the displacement channel, and pass the displacement sensor top rod through the central hole of the displacement front limit into the cabinet;

[0020] Step 2: push the displacement sensor to the bottom of the displacement channel, symmetrically lock and fix it on the channel rear limit, and then connect the displacement sensor to the data acquisition system;

[0021] Step 3: observe the zero state of the displacement sensor top rod, and control the linear motion mechanism to coarsely adjust the zero by operating the human-computer interaction unit.

[0022] Step four: observe the zero position of the displacement sensor top rod, and operate the zero position adjusting mechanism to control the high-precision electric push rod to fine-tune the zero position;

[0023] Step five: calibration:

[0024] The man-machine interaction unit is operated to select the calibration channel and sensor parameters, and the linear motion mechanism is moved to complete batch calibration; the sensor parameters include the number of steps, the maximum displacement, the channel number, and the step length of each step;

[0025] Step six: save or export the calibration data.

[0026] Further, in step five: when the ranges of the displacement sensors to be calibrated are different, the displacement sensor with the largest range is selected first for calibration, then the displacement sensor with the second largest range is selected for calibration, and so on.

[0027] Further, in step five: after selecting the sensor parameters, the controller automatically calculates the step length and the number of steps to confirm the executability of the input parameters of the calibrated sensor, and if there is a contradiction among multiple sensor parameters, a prompt will be automatically issued.

[0028] Further, in step five, during the calibration process, the controller will judge in real time whether the linearity and repeatability displacement deviation meet the calibration requirements according to the data of the acquisition system, and will return the corresponding prompt on the touch panel computer when they do not meet the requirements.

[0029] The beneficial effects of the present application are:

[0030] 1. The present application uses a high-precision motor as the power source, and a special calibration platform is designed. Through the cooperation of the linear motion mechanism and the zero position adjusting mechanism, the batch calibration and automation of the zero position adjustment during displacement calibration are realized, the errors caused by the forward and reverse stroke cycle calibration and the unreliable factors in manual calibration operation are eliminated, and the calibration quality and efficiency are greatly improved.

[0031] 2. The present application specially designs a displacement sensor fixing mechanism, which is convenient to disassemble and assemble. Before calibration, it only needs to be inserted, and after calibration, it can be pulled out. After the whole calibration device is packaged, only the displacement rod enters the box, reducing external pollution and interference.

[0032] 3. The traditional calibration process generally uses an extensometer, a high-precision vernier caliper, a gauge block, etc. for displacement sensor calibration, which has low precision. The present application uses a high-precision linear slide with a grating ruler as the ruler, which has high linear position accuracy and is superior to conventional standard measuring instruments.

[0033] 3. This invention utilizes a zero-position adjustment mechanism with a high-precision electric push rod as its core to fine-tune the zero position of the displacement sensor, which can eliminate the initial zero-position differences that exist in the batch calibration of displacement sensors, and make the calibration process of all sensors in the batch calibration highly consistent.

[0034] 4. This invention designs a more scientific human-computer interaction mode, balancing automation and autonomy in input, observation, judgment, and adjustment.

[0035] 5. This invention has high calibration efficiency, low labor costs, is easy to operate, has strong compatibility, and is easy to promote. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the automatic calibration device of the present invention.

[0037] Figure 2 This is a schematic diagram of the upper panel of the automatic calibration device of the present invention.

[0038] Figure 3 This is a partial schematic diagram of the interior of the automatic calibration device of the present invention.

[0039] Figure 4 This is a schematic diagram of the human-computer interaction interface of the automatic calibration device of the present invention.

[0040] Reference numerals: 1-Box body, 2-Box cover, 3-Zeroing button, 4-Drive circuit, 5-Electric push rod fixing plate, 6-High-precision electric push rod, 7-High-precision linear slide rail platform, 8-Observation window, 9-Electric push rod top plate, 10-Linear slide rail, 11-Displacement sensor top rod, 12-Displacement front limit, 13-Displacement fixing bracket, 14-Installation channel, 15-Displacement sensor, 16-Channel rear limit, 17-Top screw, 18-Touch panel computer, 19-Power module, 20-Drive circuit, 21-Control unit. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings.

[0042] like Figures 1-3 As shown, the automatic calibration device for linear displacement sensors of the present invention mainly includes a housing, a high-precision linear motion mechanism encapsulated in the housing, a zero-position adjustment mechanism, a calibration target fixing mechanism, a drive unit, a control unit, and a human-machine interaction unit.

[0043] I. High-precision linear motion mechanism

[0044] The high-precision linear motion mechanism is used for realizing batch coarse adjustment in the automatic calibration process of the linear displacement sensor; the high-precision linear motion mechanism comprises a high-precision motor, a high-precision linear sliding rail platform 7 and a linear sliding rail 10; the high-precision linear sliding rail platform 7 is arranged on the linear sliding rail 10; the high-precision linear sliding rail platform 7 is driven by the high-precision motor to move along the linear sliding rail 10, and the position accuracy of the movement can reach 1 μm; a high-precision grating ruler is arranged on the installation base of the linear sliding rail 10 as a scale, so as to facilitate observation and reading of the movement stroke of the high-precision linear sliding rail platform 7 in the calibration process; the repeat accuracy of the high-precision motor is 5 μm, which is better than the accuracy requirement of the calibration target on the calibration source; the calibration point controlled by the high-precision motor is more accurate than manual operation in the calibration process, and it is easier to realize positive and negative stroke cycle calibration, has better repeatability, and eliminates the manual operation error.

[0045] II. Zero adjustment mechanism

[0046] The zero adjustment mechanism comprises a zero adjustment button 3, a plurality of driving circuits 4 and a plurality of high-precision electric push rods 6; the end of the high-precision electric push rod 6 is provided with an electric push rod top disc 9; the high-precision electric push rod 6 is arranged on the high-precision linear sliding rail platform 7 and coaxially arranged one by one corresponding to each linear displacement sensor to be calibrated; all the high-precision electric push rods 6 are synchronously moved relative to the linear sliding rail 10 under the driving of the high-precision linear sliding rail platform 7 to realize batch coarse adjustment and improve the calibration efficiency; after the coarse adjustment is completed, the movement stroke of the corresponding high-precision electric push rod 6 can be individually fine adjusted through the driving circuit 4, so that the electric push rod top disc 9 at the end of the high-precision electric push rod 6 is axially abutted against the displacement rod of the corresponding linear displacement sensor to be calibrated, thereby realizing the individual "zero adjustment" function of the linear displacement sensor, so as to avoid the problem of zero position offset caused by individual difference of different displacement sensors.

[0047] The control accuracy of the high-precision electric push rod 6 is 1 pulse displacement, and the displacement of the high-precision electric push rod 6 is controlled by the pressing time of the zero adjustment button 3 installed on the box 1.

[0048] III. Calibration target fixing mechanism

[0049] The calibration target fixing mechanism is used for reliably fixing the linear displacement sensor to be calibrated on the box 1, so that the linear displacement sensor to be calibrated does not displace in the calibration process; in order to improve the convenience of disassembly and assembly, the calibration target fixing mechanism comprises an installation channel 14 for accommodating the linear displacement sensor to be calibrated, a displacement front limit 12 arranged at the front end of the installation channel 14, a channel rear limit 16 arranged at the rear end of the installation channel 14 and a top screw 17; the installation channel 14, the displacement front limit 12 and the channel rear limit 16 are clamped as a whole on the displacement fixing frame 13, and the displacement fixing frame 13 is installed on the box 1.

[0050] Before using this invention for calibration, insert the linear displacement sensor to be calibrated into the mounting channel 14. The displacement push rod of the linear displacement sensor extends out after passing through the central hole of the displacement front limit 12 at the front end of the mounting channel 14. After the linear displacement sensor is inserted to the bottom, its tail end is locked by the channel rear limit 16 and the set screw 17 to restrict its degree of freedom.

[0051] III. Box

[0052] The enclosure is a load-bearing enclosure, which ensures that the high-precision linear motion mechanism and control unit inside the enclosure will not be touched during the disassembly and assembly of the linear displacement sensor to be calibrated and human-machine interaction. It also prevents foreign objects from entering the enclosure and reduces the impact of harsh environments on the components inside the enclosure, thus playing a role in load-bearing and protection.

[0053] IV. Control Unit

[0054] The control unit 21 is mainly used to receive data from the human-machine interface unit (including remote data and touchscreen data) and send pulse and direction commands to the drive unit 20. Simultaneously, the control unit is also used to collect the relative displacement of the linear guide platform 7 and the electric push rod 6 relative to the grating ruler, and to calibrate the displacement in a timely manner using a PID algorithm. The control unit 21 also receives interrupt inputs from buttons. In this embodiment, the control unit 21 uses a PIC32MX series chip, a 32-bit microcontroller with a main frequency of up to 50MHz, capable of sending high-frequency pulse signals, and equipped with SPI, UART, and other interfaces, and can use up to four timers, among other functions.

[0055] V. Human-Computer Interaction Unit

[0056] The human-computer interaction unit is used for parameter input and status display; in this embodiment, the human-computer interaction unit is a touch-screen tablet computer 18. The human-computer interaction interface is as follows: Figure 4 As shown, the system was developed using Microsoft Visual Studio and features software to enable functions such as automatic startup upon power-on, automatic saving of input data, and controller status reading. The human-machine interface allows users to input the channel number, sensor number, displacement calibration step number, and the step size for each displacement step. Control buttons include system reset, return to zero, and next step. When the "next step" button is clicked, the step number and step size for that channel are sent to the control unit 21, which then drives the linear guide platform 7 to perform the displacement.

[0057] The principle of calibrating a linear displacement sensor using this invention is as follows:

[0058] First, the motor drives the high-precision slide rail platform 7 to move, driving the high-precision electric push rod 6 mounted thereon to contact the linear displacement sensor to be calibrated; then the micro motor controls the high-precision electric push rod 6 to act, so that the electric push rod top disc 9 at the end thereof is in abutment with the displacement sensor top rod 11 to be calibrated, and then the zero position is adjusted, and then the calibration channel (such as CH1, CH2, etc. as shown in Figure 2 The high-precision motor controls the linear slide rail platform to move to complete the batch calibration action, so as to obtain the calibration data of the calibration target. The specific steps are as follows:

[0059] Step one: power on the calibration device, and pass the displacement sensor 15 to be calibrated through the displacement channel 14, and the displacement sensor top rod 11 passes through the central hole of the displacement front limit 12 to enter the box body 1;

[0060] Step two: push the displacement sensor 15 to the bottom of the displacement channel 14, and symmetrically lock the two top screws 17 on the displacement sensor 15 on the displacement rear limit 16, and then connect the displacement sensor 15 to the data acquisition system;

[0061] Step three: observe the zero position state of the displacement sensor top rod 11 from the observation window 8 on the box body 1, and operate the touch panel computer 18 to control the high-precision linear slide rail platform 7 to move along the linear slide rail 10 to coarsely adjust the zero position;

[0062] Step four: observe the zero position state of the displacement sensor top rod 11 through the observation window 8, and operate the zero adjustment button 3 to control the high-precision electric push rod 6 to finely adjust the zero position;

[0063] Step five: calibration:

[0064] operate the touch panel computer 18 to select the calibration channel (such as CH1, CH2, etc. as shown in Figure 2 and the sensor parameters (including the number of steps, the maximum displacement, the channel number, and the step length of each step), and the high-precision motor controls the linear slide rail platform to move to complete the batch calibration action;

[0065] When the ranges of the displacement sensors to be calibrated are different, the displacement sensor with the largest range is selected first for calibration, and then the displacement sensor with the second largest range is selected for calibration, and so on;

[0066] After selecting the sensor parameters through the touch panel computer 18, the controller will automatically calculate the step length and the number of steps, confirm the executability of the input parameters of the calibrated sensor, and automatically issue a prompt if the sensor parameters are contradictory;

[0067] During the calibration process, the controller will determine whether the calibration linearity and repeatability displacement deviation meet the calibration requirements according to the data of the acquisition system, and return the corresponding prompt on the touch tablet when they do not meet the requirements;

[0068] Step six: check and confirm the calibration data, save or export;

[0069] Step seven: remove the displacement sensor 15, and power off the calibration device.

Claims

1. An automatic calibration device for a high-precision linear displacement sensor, characterized in that: It includes a chassis, a linear motion mechanism, a zero-position adjustment mechanism, a calibration target fixing mechanism, a drive unit, a control unit, and a human-machine interface unit housed within the chassis; The linear motion mechanism includes a high-precision motor, a linear slide platform, a linear slide, and a grating ruler; the linear slide platform is mounted on the linear slide and is driven by the high-precision motor to move along the linear slide; the grating ruler is mounted on the mounting base of the linear slide. The zero-position adjustment mechanism is mounted on the linear motion mechanism, which drives the linear motion mechanism to perform linear motion, thereby realizing batch coarse zeroing and calibration of the linear displacement sensors to be calibrated. The zero-position adjustment mechanism includes a zero-adjustment button, several drive circuits, and several electric push rods. The electric push rods are mounted on the linear slide rail platform and are coaxially arranged in correspondence with each linear displacement sensor to be calibrated. The push rod end of the electric push rod is provided with an electric push rod top plate. The zero-position adjustment mechanism is used to achieve individual fine-tuning of the linear displacement sensor to be calibrated to zero; The calibration target fixing mechanism is used to fix the linear displacement sensor to be calibrated onto the chassis. The control unit is used to receive data from the human-machine interaction unit and send pulse commands and direction commands to the drive unit to control the linear motion mechanism and the zero-position adjustment mechanism; The human-computer interaction unit is used to input and display parameters.

2. The high-precision linear displacement sensor automatic calibration device according to claim 1, characterized in that: The calibration target fixing mechanism includes an installation channel for accommodating the linear displacement sensor to be calibrated, a front displacement limiter set at the front end of the installation channel, a rear channel limiter set at the rear end of the displacement channel, and a set screw; the installation channel, the front displacement limiter, and the rear channel limiter are clamped together on the displacement fixing frame and installed on the housing through the displacement fixing frame.

3. The high-precision linear displacement sensor automatic calibration device according to claim 2, characterized in that: The chassis is equipped with an observation window.

4. A method for calibrating a linear displacement sensor using the high-precision linear displacement sensor automatic calibration device according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Power on the machine and insert the displacement sensor to be calibrated through the displacement channel. The displacement sensor push rod enters the housing through the central hole of the displacement front limit. Step 2: Push the displacement sensor to the bottom of the displacement channel, symmetrically lock it on the rear limit of the channel to fix it, and then connect the displacement sensor to the data acquisition system; Step 3: Observe the zero position status of the displacement sensor push rod, and operate the human-machine interaction unit to control the linear motion mechanism to coarsely adjust the zero position; Step 4: Observe the zero position status of the displacement sensor push rod, and operate the zero position adjustment mechanism to control the high-precision electric push rod to fine-tune the zero position; Step 5: Calibration: Operate the human-machine interface unit, select the calibration channel and sensor parameters, and the linear motion mechanism completes the batch calibration; the sensor parameters include the number of steps, maximum displacement, channel number, and step length of each step; Step 6: Save or export the calibration data.

5. The method for calibrating a linear displacement sensor using a high-precision linear displacement sensor automatic calibration device according to claim 4, characterized in that: In step five: when the ranges of the displacement sensors to be calibrated are different, the displacement sensor with the largest range should be selected for calibration first, then the displacement sensor with the next largest range should be selected for calibration, and so on.

6. The method for calibrating a linear displacement sensor using a high-precision linear displacement sensor automatic calibration device according to claim 5, characterized in that: In step five: After selecting the sensor parameters, the controller will automatically calculate the step size and number of steps to confirm the feasibility of the input parameters of the calibrated sensor. If multiple sensor parameters conflict, a prompt will be automatically issued.

7. The method for calibrating a linear displacement sensor using a high-precision linear displacement sensor automatic calibration device according to claim 6, characterized in that: Step 5: During the calibration process, the controller will determine in real time whether the calibration linearity and repeatability displacement deviation meet the calibration requirements based on the data collected from the acquisition system. If they do not meet the requirements, the controller will return the corresponding prompts on the touch tablet.

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