Testing device of linear displacement sensor and testing method thereof

Abstract

The invention relates to a testing device of a linear displacement sensor and a testing method thereof, and the testing device comprises a mounting base which comprises a substrate and a door vertical plate; the moving mechanism comprises a linear module, an induction sheet and a grating ruler, and the grating ruler is used for measuring the position of the induction sheet relative to the substrate; the carrying mechanism comprises a carrying plate, and a long hole and a picking groove are formed in the carrying plate; and the pressing mechanism comprises a pressing plate and a lifting driving part, and the pressing plate is vertically opposite to the carrier plate. According to the testing device, the linear displacement sensor can be pressed by the pressing plate for detection, movement of the linear displacement sensor caused by electromagnetic induction in the detection process is avoided, the detection result is accurate, and the feeding and discharging efficiency is high. The testing method comprises the steps of feeding, calibration, error detection and discharging. According to the test method, required displacement values and signal output values can be acquired in pairs, then detection of a plurality of errors is completed, and the detection efficiency is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection, in particular to a testing device for linear displacement sensor and a testing method thereof. BACKGROUND

[0002] The linear displacement sensor (LPS) is mainly used for detecting the displacement of the steering rack, and calculating the steering angle to provide accurate rear wheel steering control for the vehicle. The working principle of the linear displacement sensor is based on the inductance coupling between the transmitting coil, the target metal slider and the three receiver coils, and the output changes the detection signal. Therefore, the linear displacement sensor belongs to the inductance displacement sensor, and the movement of the detection object will cause the change of the magnetic force in the error detection of the linear displacement sensor, which in turn causes the movement of the linear displacement sensor, so that the accurate measurement cannot be achieved. If the linear displacement sensor is fixed on the carrier plate during the detection process, the tightening screw is relatively slow, which cannot meet the requirements of high-speed detection.

[0003] Chinese patent CN111457875A discloses a multifunctional detection method and device based on linear displacement sensor, which comprises a base, a linear motor, a high-precision grating displacement sensor, a test linear displacement sensor and a main control unit, and the base is fixedly connected with a guide rail; the linear motor comprises a motor rotor movably connected with the guide rail and a motor stator fixedly connected with the base; the high-precision grating displacement sensor and the test linear displacement sensor both comprise a fixed part and a detection probe movably connected with the fixed part, the fixed parts of the high-precision grating displacement sensor and the test linear displacement sensor are fixed in parallel on the base, and the detection probes of the high-precision grating displacement sensor and the test linear displacement sensor are fixedly connected with the motor rotor; the high-precision grating displacement sensor and the linear motor are electrically connected with the main control unit, and the output ends of the high-precision grating displacement sensor and the test linear displacement sensor are electrically connected with a data acquisition unit. Here, the fixed part of the test linear displacement sensor is directly fixed on the base, the detection probe is fixedly connected with the motor rotor, the displacement data is obtained by the high-precision grating displacement sensor through the movement of the detection probe driven by the linear motor, and the corresponding detection signal is output by the detection probe, so this linear displacement sensor belongs to the potentiometer type displacement sensor, and therefore there is no risk of movement of the linear displacement sensor, and the positioning and efficiency problems of the inductance displacement sensor cannot be solved.

[0004] Therefore, it is necessary to provide a special testing device to solve the above problems. SUMMARY

[0005] The main purpose of the present application is to provide a testing device for linear displacement sensor, which has compact structure, can detect the linear displacement sensor by pressing the linear displacement sensor with the pressing plate, avoids the movement of the linear displacement sensor caused by electromagnetic induction in the detection process, and has accurate detection results and high feeding and discharging efficiency.

[0006] The application achieves the above-mentioned purpose by the following technical scheme: a testing device of a linear displacement sensor, comprising: A mounting base comprising a base plate and a door upright plate vertically arranged on the base plate; A moving mechanism arranged on the base plate, comprising a linear module horizontally mounted on the base plate, a sensing sheet driven by the linear module to move linearly, and a grating ruler arranged on one side of the linear module, the grating ruler being used to measure the position of the sensing sheet relative to the base plate; A supporting mechanism arranged on the base plate, comprising a supporting plate, a long hole on the supporting plate matching the moving path of the sensing sheet, and a pickup slot on the supporting plate for positioning the linear displacement sensor, the long hole extending through the thickness direction of the supporting plate, and the pickup slot extending to both sides of the long hole; A pressing mechanism arranged on the base plate, comprising a pressing plate and a lifting driving element driving the pressing plate to lift, the pressing plate being opposite to the supporting plate in the up-down direction.

[0007] Specifically, the mounting base comprises a base plate, a door upright plate vertically arranged on the base plate, and a plurality of reinforcing ribs connected to the base plate and the door upright plate at an included angle, the door upright plate being a flat plate in a door-shaped structure, the upper part of the door upright plate being fixed with the pressing mechanism, and the lower part of the door upright plate being penetrated by the moving mechanism.

[0008] Further, the linear module comprises an electric cylinder and a moving seat driven by the electric cylinder to move linearly, the sensing sheet being arranged on the upper part of the moving seat, and the electric cylinder penetrating the inside of the door upright plate.

[0009] Further, the supporting mechanism further comprises four air springs and two height limiting columns, the lower ends of the four air springs being seated on the base plate, the upper ends of the four air springs being connected to the four corners of the supporting plate respectively, the two height limiting columns being equal in height and having upper ends connected to the lower surface of the supporting plate, and the two height limiting columns being arranged on both sides of the moving mechanism.

[0010] Further, the lifting driving element is connected to one side of the door upright plate, and the lifting driving element is a sliding table air cylinder.

[0011] Specifically, the pressing mechanism further comprises a pressing frame connecting the lifting driving element and the pressing plate, the pressing plate being arranged at the bottom of the pressing frame, and the pressing plate and the pressing frame constituting a cuboid structure.

[0012] Another main purpose of the application is to provide a testing method of a linear displacement sensor, which can detect various errors by using the linear displacement sensor testing device.

[0013] A testing method of a linear displacement sensor, which is completed by using any of the testing devices, and the steps comprise: S1, loading: the linear displacement sensor is positioned and placed in the pickup groove, the detection area of the linear displacement sensor is exposed downward from the long hole, and then the pressing plate is used to press the linear displacement sensor, so that the linear displacement sensor and the inductive sheet reach a proper detection distance; S2, calibration: after the linear displacement sensor is powered on, the inductive sheet moves to the mechanical leftmost position, moves to the mechanical rightmost position at a specified moving speed, and in this process, the displacement value x of the inductive sheet is collected through the grating ruler, the linear displacement sensor can simultaneously obtain two signal output values y1 and y2, the changes of (x, y1) and (x, y2) are independently drawn into signal output curves and placed on the same graph, and two clamping limit displacement values x a and x b are obtained according to the mutation positions of the signal output values a and y b , and then the output clamping is configured, the middle of the linear displacement sensor is , , and the signal output theoretical value of ; S3, error detection: after the linear displacement sensor is powered on again, the inductive sheet moves to the mechanical leftmost position again, moves to the mechanical rightmost position at a specified moving speed, and collects a group of data (x, y1, y2) every certain distance, y1 is the signal output measured value of the first channel when the inductive sheet 42 is at the x position, y2 is the signal output measured value of the second channel when the inductive sheet 42 is at the x position, and then various error calculations are performed; S4, unloading: the pressing plate is raised to separate from the linear displacement sensor, and then the linear displacement sensor that has been detected is taken away from the carrier plate.

[0014] Specifically, the calculation method of the total error and the diagnostic error is: , ; x 1cal is the calculated value of x according to y1 under the first channel, x 2cal is the calculated value of x according to y2 under the second channel, and k is the x-y conversion coefficient of the linear displacement sensor; , ; M 1err is the total error under the first channel, M 2err is the total error under the second channel; = ; Diagnose the error of the linear displacement sensor.

[0015] Specifically, the calculation method of the slope error is: fitting all (x, , y) as a first straight line to obtain a slope g1, fitting all (x, , y) as a second straight line to obtain a slope g2, and then calculating the slope error G 1err and G 2err : , ; g1 is the slope of the first straight line, g2 is the slope of the second straight line, G 1err is the slope error of the first straight line, and G 2err is the slope error of the second straight line.

[0016] Further, according to the first straight line and the second straight line, the displacement fitting value corresponding to x in the first straight line is found first, and then the displacement fitting value corresponding to x in the second straight line is found: Then the nonlinear error N 1err and N 2err are calculated: , ; N is the nonlinear error of the first channel, and N is the nonlinear error of the second channel.

[0017] The beneficial effects of the technical scheme of the present application are: 1. The test device can press the linear displacement sensor with a pressing plate for detection, avoiding the movement of the linear displacement sensor caused by electromagnetic induction during detection, and the detection result is accurate and the feeding and discharging efficiency is high.

[0018] 2. The test method can collect the required displacement value and signal output value in pairs, and then complete multiple error detection, and the detection efficiency is high. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a perspective view of the test device of the linear displacement sensor of the embodiment; Figure 2 is a perspective view of the linear displacement sensor when placed by the supporting mechanism; Figure 3 is a connection relationship diagram of the mounting base and the pressing mechanism; Figure 4 is a connection relationship diagram of the mounting base and the moving mechanism; Figure 5The detection principle diagram of the linear displacement sensor; Figure 6 The signal output curve diagram after the configuration is completed; Figure 7 The conversion principle diagram of the signal output value and the displacement value.

[0020] The numbers in the figure represent: 100-test device, 1-mounting base, 11-base plate, 12-door upright plate, 13-reinforcing rib; 2-carrying mechanism, 21-carrier plate, 211-long hole, 212-pickup groove, 22-air spring, 23-height limiting column; 3-pressing mechanism, 31-pressing plate, 32-lifting driving part, 33-pressing frame; 4-moving mechanism, 41-linear module, 411-electric cylinder, 412-moving seat, 42-induction sheet, 43-grating ruler; 200-linear displacement sensor. DETAILED DESCRIPTION

[0021] The application will be further described in detail below in combination with specific embodiments.

[0022] Embodiment: As shown in the figure, a test device 100 of a linear displacement sensor 200 of the application, comprising a mounting base 1, a carrying mechanism 2, a pressing mechanism 3 and a moving mechanism 4, the carrying mechanism 2, the pressing mechanism 3 and the moving mechanism 4 are all arranged on the mounting base 1. Figure 1 As shown in the figure, the mounting base 1 comprises a base plate 11, a door upright plate 12 vertically arranged on the base plate 11 and a plurality of reinforcing ribs 13 connected in the included angle between the base plate 11 and the door upright plate 12.

[0023] Figure 2 The base plate 11 is the fixed base of the carrying mechanism 2 and the moving mechanism 4. The door upright plate 12 is a flat plate of door-shaped structure, the upper part of the door upright plate 12 is fixed with the pressing mechanism 3, and the lower part is penetrated by the moving mechanism 4. The reinforcing ribs 13 are used to keep the base plate 11 and the door upright plate 12 in a vertical state, so that the whole test device 100 has sufficient structural rigidity and avoids inaccurate action between parts.

[0024] The base plate 11 is the fixed base of the carrying mechanism 2 and the moving mechanism 4. The door upright plate 12 is a flat plate of door-shaped structure, the upper part of the door upright plate 12 is fixed with the pressing mechanism 3, and the lower part is penetrated by the moving mechanism 4. The reinforcing ribs 13 are used to keep the base plate 11 and the door upright plate 12 in a vertical state, so that the whole test device 100 has sufficient structural rigidity and avoids inaccurate action between parts.

[0025] As shown in the figure, the mounting base 1 comprises a base plate 11, a door upright plate 12 vertically arranged on the base plate 11 and a plurality of reinforcing ribs 13 connected in the included angle between the base plate 11 and the door upright plate 12. Figure 1 Figure 2 ​​As shown, the supporting mechanism 2 includes a supporting plate 21, four air springs 22 and two height limiting posts 23. The supporting plate 21 is provided with a long hole 211 matching the moving path of the sensing sheet 42 and a pickup groove 212 for positioning the linear displacement sensor 200, the long hole 211 extends through the thickness direction of the supporting plate 21, and the pickup groove 212 extends to both sides of the long hole 211. The lower ends of the four air springs 22 are seated on the base plate 11, and the upper ends are connected to the four corners of the supporting plate 21. The two height limiting posts 23 are of the same height and are connected to the lower surface of the supporting plate 21, and are respectively arranged on both sides of the moving mechanism 4.

[0026] The supporting plate 21 is a positioning supporting part of the linear displacement sensor 200, and is used for embeddedly placing the linear displacement sensor 200. The length direction of the long hole 211 is along the length direction of the linear displacement sensor 200, and allows the sensing sheet 42 to translate in a place very close to the lower surface of the linear displacement sensor 200. The four air springs 22 make the supporting plate 21 be smoothly lifted, and after the pressing plate 31 presses the upper surface of the linear displacement sensor 200, the four air springs 22 are synchronously compressed until the lower ends of the two height limiting posts 23 simultaneously contact the upper surface of the base plate 11. Because the moving mechanism 4 has occupied part of the space above the base plate 11, the height limiting posts 23 need to be positionally staggered with the moving mechanism 4 to be able to contact the upper surface of the base plate 11.

[0027] As shown, Figure 3 The pressing mechanism 3 includes a pressing plate 31, a lifting driving part 32 for driving the pressing plate 31 to lift and fall, and a pressing frame 33 connecting the lifting driving part 32 and the pressing plate 31. The pressing plate 31 is opposite to the supporting plate 21 in the up-down direction. The lifting driving part 32 is fixed to the upper part of the door stand 12 and drives the pressing plate 31 to lift and fall through the pressing frame 33. The pressing plate 31 is arranged at the bottom of the pressing frame 33, and the pressing plate 31 and the pressing frame 33 form a cuboid structure. The lifting driving part 32 is a slide table air cylinder.

[0028] The lower surface of the pressing plate 31 is used to cooperate with the upper surface of the supporting plate 21 to clamp the linear displacement sensor 200 in the up-down direction. The pressing frame 33 is a part with high structural rigidity, and can make the lower surface of the pressing plate 31 still keep in the horizontal direction after the pressing plate 31 is subjected to the reaction force of the linear displacement sensor 200, so as to ensure that the linear displacement sensor 200 is pressed tightly and avoid that the linear displacement sensor 200 cannot keep in the original position due to the interference during detection. Before feeding, the pressing plate 31 needs to be retreated to the high position of the testing device 100, so as to leave a height space for placing the linear displacement sensor 200 on the supporting plate 21. The slide table air cylinder itself has a direction guiding effect, and can make the pressing plate 31 accurately move along the vertical direction.

[0029] As shown, Figure 4As shown, the moving mechanism 4 includes a linear module 41 horizontally mounted on the base plate 11, a sensing sheet 42 driven by the linear module 41 to move linearly, and a grating ruler 43 located on one side of the linear module 41, which is used to measure the position of the sensing sheet 42 relative to the base plate 11. The linear module 41 includes an electric cylinder 411 and a moving seat 412 driven by the electric cylinder 411 to move linearly, and the sensing sheet 42 is arranged on the upper part of the moving seat 412. The electric cylinder 411 passes through the inside of the door upright plate 12.

[0030] The electric cylinder 411 is a modular component of the integrated design of a servo motor and a screw rod, which can convert the rotary motion of the servo motor into the linear motion of the moving seat 412. The sensing sheet 42 is fixed on the moving seat 412 and translates at a height close to the lower surface of the linear displacement sensor 200, thereby causing the linear displacement sensor 200 to output a sensing signal. The electric cylinder 411 occupies the space in the middle of the base plate 11, and the door upright plate 12 is needed to fix the pressing mechanism 3 above the electric cylinder 411, so the door upright plate 12 needs to be staggered with the door structure. The grating ruler 43 is used to detect the position change of the sensing sheet 42 in real time (represented by the position of the moving seat 412). Therefore, the corresponding data of the signal output value y and the displacement value x of the sensing sheet 42 can be collected, so as to realize the calculation of the correlation performance. The correlation performance includes total error, slope error, nonlinearity, symmetry error and diagnostic error, etc. The test device can press the linear displacement sensor 200 with the pressing plate 31 for detection, which avoids the movement of the linear displacement sensor 200 caused by electromagnetic induction in the detection process, and the detection result is accurate and the feeding and discharging efficiency is high.

[0031] As shown in FIG. 1, Figures 1 to 5 The test method of the linear displacement sensor 200 includes the following steps: S1, feeding: positioning and placing the linear displacement sensor 200 on the carrier plate 21 (specifically on the pickup groove 212), so that the detection area of the linear displacement sensor 200 is exposed downward from the long hole 211, and then pressing the linear displacement sensor 200 with the pressing plate 31 to make the linear displacement sensor 200 and the sensing sheet 42 reach a proper detection distance.

[0032] In this embodiment, the carrier plate 21 is lowered, so that the distance between the linear displacement sensor 200 and the sensing sheet 42 is 0.7 mm. In this way, the movement of the sensing sheet 42 can cause the linear displacement sensor 200 to output a signal that changes with the displacement value.

[0033] S2, calibration: after the linear displacement sensor 200 is powered on, the sensing sheet 42 moves to the mechanical leftmost position, and moves to the mechanical rightmost position at a specified moving speed, in the process, the displacement value x of the sensing sheet is collected by the grating ruler 43, the linear displacement sensor 200 can obtain two signal output values y1 (the signal output measured value of the first channel DIE A) and y2 (the signal output measured value of the second channel DIE B) at the same time, the changes of (x, y1) and (x, y2) are independently drawn into a signal output curve and placed on the same graph, as shown in Figure 6 and Figure 7 . According to the mutation position of the signal output value, two clamping limit displacement values x a and x b and the limit output values y a and y b corresponding to the two clamping limit displacement values are obtained, and then the output clamping is configured, the middle (close to the middle of the long hole 211) of the linear displacement sensor 200 is , , and the signal output theoretical value of the middle is .

[0034] In theory, there is a fixed offset between the displacement value measured by the grating ruler 43 and the displacement value obtained by the linear displacement sensor 200, and the displacement coordinate obtained by the linear displacement sensor 200 is only in a proportional relationship (the proportion is the x-y conversion coefficient k) with . Because , and are constants, so , the result is a constant value, that is, the same x corresponds to and are complementary within the allowable error range, from Figure 6 , it can be known that the signal output curve has a obvious "platform" in the extension part of the clamping limit, which is the most easily and accurately measured, so the clamping limit data needs to be calibrated.

[0035] S3, error detection: after the linear displacement sensor 200 is powered on again, the sensing sheet moves to the mechanical leftmost position again, moves to the mechanical rightmost position at a specified moving speed, and collects a group of data (x, y1, y2) every set distance, y1 is the signal output measured value of the first channel when the sensing sheet 42 is at x position, y2 is the signal output measured value of the second channel when the sensing sheet 42 is at x position, and then various error calculations are performed.

[0036] First, calculate x 1cal and x 2cal : , ; x 1cal is the calculated value of x according to y1 under the first channel, x 2cal is the calculated value of x according to y2 under the second channel, and k is the x-y conversion coefficient of the linear displacement sensor.

[0037] In theory, the x-y curve under the first channel and the x-y curve under the second channel should both be straight lines passing through (0, ), and the slope of the former is k and the slope of the latter is -k. However, there will be errors in actual measurement, resulting in and x all have small errors.

[0038] Then calculate the total error M 1err and M 2err : , ; M 1err is the total error under the first channel, and M 2err is the total error under the second channel.

[0039] In actual measurement, x is within the measurement interval, and each M 1err and M 2err must be within the error range (±0.15mm in this embodiment) to determine that the total error of the linear displacement sensor 200 is qualified.

[0040] = .

[0041] is the diagnostic error of the linear displacement sensor 200.

[0042] In actual measurement, x is within the measurement interval, and each must be within the error range (±0.2mm in this embodiment) to determine that the diagnostic error of the linear displacement sensor 200 is qualified.

[0043] According to the least squares method, all (x, ) are fitted as the first straight line to obtain the slope g1, and all (x, ) are fitted as the second straight line to obtain the slope g2, and then the slope error G 1err and G 2err are calculated: , ; g1 is the slope of the first straight line, g2 is the slope of the second straight line, G 1err is the slope error of the first straight line, and G 2err is the slope error of the second straight line.

[0044] Because x≈ , theoretically, the slope g1, g2 of the first and second straight line after linear fitting is close to 1. Therefore, the difference between the slope and 1 is taken as the slope error value, so as to determine whether the slope error meets the standard.

[0045] Similarly, according to the first and second straight lines, the displacement fitting value corresponding to x in the first straight line is found , and the displacement fitting value corresponding to x in the second straight line is found : Then the nonlinear error N 1err and N 2err : , ; is the nonlinear error of the first channel, is the nonlinear error of the second channel.

[0046] According to whether and are within the error range, it is judged whether the nonlinear error meets the standard.

[0047] S4, discharging: the pressing plate 31 is raised, thereby separating from the linear displacement sensor 200, and then the linear displacement sensor 200 which has been detected is taken away from the carrier plate 21.

[0048] The test method can pair the required displacement value and signal output value, and then complete multiple error detection, so the detection efficiency is high.

[0049] The above only describes some embodiments of the present application. For those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A testing device for a linear displacement sensor, characterized in that The application relates to a linear displacement sensor loading and unloading device. The device comprises a mounting base, a moving mechanism, a supporting and loading mechanism and a pressing mechanism. The mounting base comprises a base plate, a door-shaped vertical plate arranged on the base plate and a plurality of reinforcing ribs connected to the base plate and the door-shaped vertical plate. The door-shaped vertical plate is a flat plate with a door-shaped structure, the upper part of the door-shaped vertical plate is fixed with the pressing mechanism, and the lower part of the door-shaped vertical plate is penetrated by the moving mechanism. The linear module comprises an electric cylinder and a moving seat driven by the electric cylinder to move linearly, the inductive sheet is arranged on the upper part of the moving seat, and the electric cylinder penetrates the inside of the door-shaped vertical plate.

2. The testing device of a linear displacement sensor according to claim 1, characterized in that: The supporting and loading mechanism further comprises four air springs and two height limiting columns, the lower ends of the four air springs are arranged on the base plate, the upper ends of the four air springs are connected to the four corners of the loading plate respectively, the two height limiting columns are arranged at the same height and the upper ends of the two height limiting columns are connected to the lower surface of the loading plate, and the two height limiting columns are arranged on the two sides of the moving mechanism.

3. A test apparatus for a linear displacement sensor according to claim 2, characterised in that: The lifting driving element is connected to one side of the door-shaped vertical plate, and the lifting driving element is a sliding table air cylinder.

4. The test device for a linear displacement sensor according to claim 2, characterized in that: The pressing mechanism further comprises a pressing frame connected to the lifting driving element and the pressing plate, the pressing plate is arranged at the bottom of the pressing frame, and the pressing plate and the pressing frame form a cuboid structure.

5. The test apparatus for a linear displacement sensor of claim 2, wherein: The steps comprise the following steps.

6. The test apparatus for a linear displacement sensor of claim 1, wherein: S1, feeding: the linear displacement sensor is positioned and placed in the pickup slot, the detection area of the linear displacement sensor is exposed downward from the long hole, then the linear displacement sensor is pressed by the pressing plate, and the linear displacement sensor and the inductive sheet reach a proper detection distance.

7. The method of claim 1, wherein the method is performed using the apparatus of any one of claims 1-6. S3, error detection: after the linear displacement sensor is powered on again, the inductive sheet is moved to the mechanical leftmost position again, is moved to the mechanical rightmost position at a specified moving speed, a group of data (x, y1, y2) is collected every certain distance, y1 is the signal output measured value of the first channel when the inductive sheet 42 is at the x position, y2 is the signal output measured value of the second channel when the inductive sheet 42 is at the x position, then various error calculations are carried out. S1, discharging: the pressing plate is lifted to be separated from the linear displacement sensor, and then the linear displacement sensor which has been detected is taken away from the loading plate. S2, calibration: after the linear displacement sensor is powered on, the sensing sheet moves to the mechanically leftmost position, and moves to the mechanically rightmost position at a specified moving speed, in the process, the displacement value x of the sensing sheet is collected by the grating ruler, the linear displacement sensor can simultaneously obtain two signal output values y1 and y2, the changes of (x, y1) and (x, y2) are independently drawn into signal output curves and placed on the same graph, two clamping limit displacement values x a and x b are obtained according to the mutation positions of the signal output values, and the limit output values y a and y b corresponding to the two clamping limit displacement values are obtained, then the output clamping is configured, the middle position of the linear displacement sensor is , , and the signal output theoretical value is ; The calculation method of the total error and the diagnostic error is as follows. ​ 8. The method of testing a linear displacement sensor of claim 1, wherein: ​ ， ； x 1cal x is the calculated value of x according to y1 under the first channel, x 2cal x is the calculated value of x according to y2 under the second channel, k is the x-y conversion factor of the linear displacement sensor ， ； M 1err M is the total error under the first channel 2err M is the total error under the second channel = ； diagnostic error for the linear displacement sensor.

9. The method of testing a linear displacement sensor of claim 1, wherein: The calculation method of the slope error is: fitting all (x, ) as a first straight line to obtain a slope g1, fitting all (x, ) as a second straight line to obtain a slope g2, and then calculating a slope error G 1err and G 2err : ， ； g1 is the slope of the first line, g2 is the slope of the second line, G 1err is the slope error of the first line, G 2err is the slope error of the second line.

10. The method of testing a linear displacement sensor of claim 9, wherein: According to the first straight line and the second straight line, first find the displacement fitting value corresponding to x in the first straight line , and then find the displacement fitting value corresponding to x in the second straight line . The non-linear error N is then calculated 1err and N 2err : ， ； nonlinear error for the first channel, nonlinear error for the second channel.

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