Inductance encoder precision adjusting and measuring device and method

Abstract

The invention discloses an inductance encoder precision adjusting and testing device which comprises a rotary table controller, an upper computer and a rotary table, the upper computer and the rotary table are electrically connected with the rotary table controller, the output end of the rotary table is provided with a rotary table used for installing a rotor of an inductance encoder, the outer end of the rotary table is further provided with a stator support, and the lower end of the stator support is provided with an axial gap adjusting device. The stator support is used for installing a stator of the inductance encoder. The invention further discloses an inductance encoder precision adjusting and measuring method, the axial gap adjusting device is used for adjusting the axial gap between the stator and the rotor of the inductance encoder, and therefore mechanical adjusting and measuring of the inductance encoder are completed. An electrical compensation command is further used to perform error compensation on angular deviations that cannot be calibrated by mechanical adjustment. According to the inductance encoder precision adjusting and testing device and method, based on the idea of software and hardware combination, the precision adjusting and testing idea of combining mechanical adjustment and electrical compensation is carried out, the precision adjusting and testing efficiency of the inductance encoder is greatly improved, and meanwhile high-precision optimization can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to an encoder testing device and a method for testing an encoder by using the same, and in particular, to an inductance encoder precision testing device and a method for testing an inductance encoder by using the same. BACKGROUND

[0002] As a high-precision angle measurement sensor, the inductance encoder is widely used in the fields of aerospace and industrial automation due to its strong anti-interference ability and good environmental adaptability. These fields have very high requirements for measurement accuracy, usually reaching the angle second level, so the inductance encoder must be strictly tested and error compensated during production. At present, the industry generally uses the manual repeated disassembly and calibration method to test the precision of the inductance encoder, which results in low efficiency, poor consistency and inability to quantify mechanical installation errors. In order to solve the above problems, Chinese patent CN119915332A discloses a PCB type inductance encoder signal error compensation method and device, which proposes a signal error compensation scheme that processes errors caused by voltage waveform deviation through a small period / large period compensation algorithm. However, this scheme still has the following defects: first, it cannot correct installation errors; second, it lacks precision verification reference; and third, the electrical compensation does not form a closed loop with the mechanical testing means, making it difficult to achieve high-precision optimization. SUMMARY

[0003] The purpose of the present application is to solve the technical problems of the existing inductance encoder error compensation method and testing device, which cannot correct installation errors, lack precision verification reference, and the electrical compensation does not form a closed loop with the mechanical testing means, making it difficult to achieve high-precision optimization, and to provide an inductance encoder precision testing device and method.

[0004] To achieve the above purpose, the technical solution adopted by the present application is as follows:

[0005] An inductance encoder precision testing device, characterized in that it comprises a rotary table controller, an upper computer and a base;

[0006] The base is provided with a rotary table and a housing outside the rotary table; the housing is provided with a stator support outside the output end of the rotary table; the output end of the rotary table is provided with a turntable for connecting with the rotor of the inductance encoder to be tested;

[0007] The rotary table controller is electrically connected with the control end of the rotary table for controlling the rotation angle of the output end of the rotary table, and is electrically connected with the upper computer for transmitting the rotation angle information of the output end of the rotary table to the upper computer;

[0008] The stator support is used for fixing the stator of the inductance encoder to be tested and adjusted, and an axial gap adjusting device is arranged between the stator support and the shell for adjusting the axial gap between the stator and the rotor of the inductance encoder to be tested and adjusted.

[0009] The upper computer is electrically connected with the signal output end on the stator of the inductance encoder to be tested and adjusted.

[0010] The upper computer is used for controlling the turntable controller to drive the turntable to rotate, collecting and comparing the rotation angles output by the turntable and the inductance encoder to be tested and adjusted, generating and displaying precision testing instructions, and adjusting the inductance encoder to be tested and adjusted according to the precision testing instructions, so that the precision of the inductance encoder to be tested and adjusted reaches the preset requirement, and then the adjustment parameters of the inductance encoder to be tested and adjusted are obtained.

[0011] Further, the axial gap adjusting device is a plurality of gaskets or telescopic sleeves with different thicknesses, which are used for adjusting the axial distance between the stator support and the shell, so as to adjust the axial gap between the stator and the rotor of the inductance encoder to be tested and adjusted, and then adjust the precision of the inductance encoder to be tested and adjusted.

[0012] Further, the upper end of the turntable is provided with a mounting blind hole matched with the shape of the rotor of the inductance encoder to be tested and adjusted, which is used for mounting the rotor of the inductance encoder to be tested and adjusted through the hole shaft cooperation of the H7 / g6 tolerance level.

[0013] Further, the coaxiality deviation between the stator support and the turntable is ≤0.5 μm by using the coaxiality detection device.

[0014] Further, the stator support and the shell are connected through a flange plate, the flange plate is provided with a through hole, the diameter of the through hole is greater than the diameter of the connecting piece, and the coaxiality of the stator support and the turntable is adjusted.

[0015] Further, the rotation precision of the turntable is ≤0.001°.

[0016] Meanwhile, the present application also provides an inductance encoder precision testing method, which adopts the inductance encoder precision testing device, and the speciality thereof lies in that the method comprises the following steps:

[0017] Step 1, hardware assembly

[0018] 1.1, the rotor of the inductance encoder to be tested and adjusted is mounted on the upper end of the turntable, and the stator of the inductance encoder to be tested and adjusted is mounted on the upper end of the stator support;

[0019] 1.2, the stator support is mounted on the upper end of the shell, and an axial gap adjusting device is arranged between the stator support and the shell, and a coaxiality detection device is used to adjust the coaxiality of the stator support and the turntable, after the adjustment is completed, the stator support is locked on the upper end of the shell;

[0020] Step 2, mechanical compensation

[0021] 2.1, the host computer controls the turntable controller to drive the rotation of the turntable, and the rotation angle θ1 of the turntable is collected;

[0022] 2.2, the host computer collects the rotation angle θ2 output by the inductance encoder to be tested through the signal output end on the stator of the inductance encoder to be tested;

[0023] 2.3, calculate the angle deviation Δθ c = θ1- θ2;

[0024] 2.4, according to the angle deviation Δθ c , adjust the axial gap between the rotor and the stator of the inductance encoder to be tested through the axial gap adjusting device;

[0025] 2.5, repeat steps 2.1-2.4 until the angle deviation Δθ c no longer decreases, then record the angle deviation Δθ c which no longer decreases as the minimum value Δθ cmin that the axial gap adjusting device can reduce the angle deviation; and record the mechanical compensation data at this time, i.e. the axial gap L between the stator and the rotor of the inductance encoder to be tested;

[0026] Step 3, electrical compensation

[0027] 3.1, the host computer controls the turntable controller to drive the rotation of the turntable, and the host computer collects:

[0028] the rotation angle θ t of the turntable;

[0029] and the rotation angle θ e output by the inductance encoder to be tested;

[0030] 3.2, calculate the angle deviation Δθ = θ t - θ e of each sampling point;

[0031] 3.3, generate electrical compensation instructions based on the angle sampling point Δθ, including:

[0032] a) construct a periodic error compensation model;

[0033] b) solve the model compensation coefficient;

[0034] c) generate a feasible compensation coefficient, and input the electrical compensation instructions including the compensation coefficient into the inductance encoder to be tested through the host computer, adjust the parameters of the inductance encoder to be tested to compensate for the angle deviation;

[0035] 3.4, error verification

[0036] Repeat steps 3.1-3.3 until the angle deviation Δθ≤ preset target accuracy, then the electrical compensation instruction in step 3.3 is taken as compensation data burned into the memory of the inductance encoder to be tested;

[0037] Step 4, production of test data multiplexing

[0038] The mechanical test data recorded in step 2.5 are taken as a guide to the axial gap L between the stator and the rotor of the same type of inductance encoder during mass production assembly, and the compensation data obtained in step 3.4 are taken as compensation data burned into the memory of the same type of inductance encoder during mass production assembly, so as to realize the test of the inductance encoder precision optimization.

[0039] Further, the electrical compensation instruction in step 3.3 is a periodic error compensation algorithm based on harmonic analysis.

[0040] Further, the error compensation algorithm in step 3.3 is constructed by the following steps:

[0041] a) A data set is established based on the angle deviation collected at multiple sampling points in step 3.1: {Δθ i , θ ei}(i=1,2,…,m) wherein Δθ i is the angle deviation value, and θ ei is the rotation angle output by the inductance encoder to be tested;

[0042] At the same time, a Fourier series error model is established: wherein N is the harmonic order, a0, a k , b k are the coefficients to be solved;

[0043] b) The Fourier series error model coefficients are solved by the least square method;

[0044] The minimization objective function is:

[0045] The minimum coefficient combination is [a0, a1, b1, …, a N , b N ] T ;

[0046] c) The minimum coefficient combination [a0, a1, b1, …, a N , b N ] T is input into the inductance encoder to be tested through the upper computer, and the parameters of the inductance encoder to be tested are adjusted to compensate for the angle deviation.

[0047] Further, the distance of the axial gap L in step 2.5 is measured by a length measuring tool;

[0048] The length measuring tool is a measuring instrument with an accuracy of ≥0.01mm

[0049] Compared with the prior art, the present application has the following beneficial effects:

[0050] 1、The inductance encoder precision adjustment device realizes automatic adjustment and measurement through the closed loop architecture of the host computer, the rotary table controller and the rotary table, realizes real-time data comparison of the rotary table and the host computer, replaces manual calibration, greatly improves the efficiency of adjustment and measurement, and adopts the combination of hardware and software to adjust the precision of the inductance encoder, so that the precision verification reliability and the adjustment precision are significantly improved.

[0051] 2、The inductance encoder precision adjustment device adjusts the axial gap between the stator and the rotor of the inductance encoder to be adjusted by the axial gap adjustment device, accurately eliminates the installation error caused by the improper axial gap between the stator and the rotor of the inductance encoder to be adjusted, and solves the defect that the traditional device cannot correct mechanical deviation.

[0052] 3、The inductance encoder precision adjustment device improves the coaxiality of the rotary table and the rotor of the inductance encoder to be adjusted through mechanical tolerance cooperation, ensures the precision of mechanical transmission, and further improves the precision of the inductance encoder.

[0053] 4、The inductance encoder precision adjustment device and method combine mechanical adjustment based on a hardware adjustable threshold and electrical adjustment based on algorithm compensation to adjust the precision of the inductance encoder, so that the precision of the inductance encoder can reach the angle second level, and meet the requirements of high-precision fields such as aerospace and industrial automation; the automatic adjustment and measurement process of the present application greatly improves the efficiency and precision of inductance encoder precision adjustment; at the same time, the present application provides an angle second level reference source, full stroke rotation verification, ensures that the adjustment and measurement result meets the target precision, and avoids the risk of no reference verification. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 It is a structural schematic view of an embodiment of the inductance encoder precision adjustment device of the present application;

[0055] Figure 2 It is a three-dimensional structural schematic view of the base, the rotary table, the shell, the stator support and the inductance encoder to be adjusted in the embodiment of the present application;

[0056] Figure 3 It is a sectional view of the base, the rotary table, the rotary table, the shell and the stator support in the embodiment of the present application;

[0057] Figure 4This is a cross-sectional view of the base, turntable, turntable, housing, stator support, and the inductor encoder to be adjusted in an embodiment of the present invention;

[0058] Figure 5 This is a three-dimensional structural diagram of the output shaft and turntable of the turntable in an embodiment of the present invention;

[0059] Figure 6 This is a flowchart illustrating an embodiment of an inductive encoder accuracy adjustment method according to the present invention;

[0060] Figure 7 This is a flowchart of step 2 in an embodiment of the inductive encoder accuracy adjustment method of the present invention.

[0061] Figure 8 This is a flowchart of step 3 in an embodiment of the inductive encoder accuracy adjustment method of the present invention.

[0062] Among them, 2-turntable controller, 3-host computer, 4-stator support, 5-turntable, 6-turntable, 7-base, 8-shell, 10-inductor encoder to be adjusted. Detailed Implementation

[0063] To better understand the purpose, structure, and function of this invention, the following detailed description of an inductive encoder accuracy adjustment device and method is provided in conjunction with the accompanying drawings.

[0064] An inductive encoder accuracy adjustment device, such as Figures 1-5 As shown, the device includes a turntable controller 2, a host computer 3, a stator support 4, a turntable 6, a base 7, a housing 8, and an axial clearance adjustment device. This device is a simulation device used to simulate the actual installation environment of the inductive encoder. It performs accuracy adjustments to the inductive encoder through a combination of mechanical adjustments and electrical compensation. After the simulation adjustment is completed, the mechanical adjustment data is recorded for subsequent actual production assembly; the electrical compensation commands are burned into the inductive encoder's memory to achieve real-time error compensation.

[0065] The host computer 3 has data acquisition and processing capabilities. Its optional hardware platform is: Intel(R) Core(TM) i5-7500 CPU with a main frequency of 3.40GHz and 16G memory; the software platform is: WINDOWS series operating system or C++.

[0066] In other embodiments, the hardware platform of the host computer 3 may be configured differently; its software platform may also be other systems with real-time data processing capabilities.

[0067] The rotary table controller 2 is electrically connected with the rotary table 6, and is used for controlling the rotation angle of the output end of the rotary table 6. The rotary table controller 2 is also electrically connected with the upper computer 3, and is used for transmitting the rotation angle information of the output end of the rotary table to the upper computer. Thus, an electrical signal path is formed from the upper computer 3 to the rotary table controller 2 and the rotary table 6. The upper computer 3 is used for editing a control instruction and sending the control instruction to the rotary table controller 2. The rotary table controller 2 is used for receiving the control instruction and driving the rotary table 6 according to the control instruction. Meanwhile, the upper computer 3 collects the rotation angle of the rotary table 6, and compares and analyzes the collected rotation angle with the rotation angle of the to-be-adjusted and measured inductive encoder 10, so as to generate a mechanical adjustment instruction or an electrical compensation instruction, which is used for precision adjustment and measurement of the to-be-adjusted and measured inductive encoder 10.

[0068] In other embodiments, the rotary table controller 2 is integrated in the rotary table 6, so as to realize the compactness of the structure. Alternatively, the rotary table controller 2 can be used as a separate component.

[0069] The base 7 is a support structure, on which the rotary table 6 is installed. The rotation precision of the rotary table 6 is less than or equal to 0.001°. The output end of the rotary table 6 is provided with a turntable 5, which is used for being connected with a rotor of the to-be-adjusted and measured inductive encoder 10. The upper end of the turntable 5 is provided with a blind hole with an H7 tolerance level, which is matched with a shaft with a g6 tolerance level on the rotor of the to-be-adjusted and measured inductive encoder 10. The rotor of the to-be-adjusted and measured inductive encoder 10 is installed on the upper end of the turntable 5, so that the turntable 5 and the rotor of the to-be-adjusted and measured inductive encoder 10 are on the same rotation axis. The rotor of the to-be-adjusted and measured inductive encoder 10 rotates synchronously with the rotary table 6.

[0070] The control end of the rotary table 6 is electrically connected with the rotary table controller 2, and is used for controlling the rotation angle of the output end of the rotary table 6. The rotary table controller 2 is also electrically connected with the upper computer 3, and is used for transmitting the rotation angle signal of the output end of the rotary table 6 to the upper computer 3.

[0071] The base 7 is a support structure, on which the rotary table 6 is installed. The rotation precision of the rotary table 6 is less than or equal to 0.001°. The output end of the rotary table 6 is provided with a turntable 5, which is used for being connected with a rotor of the to-be-adjusted and measured inductive encoder 10. The upper end of the turntable 5 is provided with a blind hole with an H7 tolerance level, which is matched with a shaft with a g6 tolerance level on the rotor of the to-be-adjusted and measured inductive encoder 10. The rotor of the to-be-adjusted and measured inductive encoder 10 is installed on the upper end of the turntable 5, so that the turntable 5 and the rotor of the to-be-adjusted and measured inductive encoder 10 are on the same rotation axis. The rotor of the to-be-adjusted and measured inductive encoder 10 rotates synchronously with the rotary table 6.

[0072] The upper computer 3 is also electrically connected with the signal output end on the stator of the to-be-adjusted and measured inductive encoder 10. Thus, the rotation angle and other data of the to-be-adjusted and measured inductive encoder 10 are transmitted to the upper computer 3.

[0073] The host computer 3 is used to control the turntable controller 2 to drive the turntable 6 to rotate, and collect the rotation angle of the turntable 6 and the rotation angle of the to-be-adjusted inductance encoder 10 for comparison and analysis, generate and display the precision adjustment instruction, and adjust the to-be-adjusted inductance encoder 10 according to the precision adjustment instruction, so that the precision of the to-be-adjusted inductance encoder 10 reaches the preset requirement, and then the adjustment parameter of the to-be-adjusted inductance encoder 10 is obtained. The mechanical adjustment instruction is mainly obtained by adjusting the axial gap adjusting device, adjusting the axial gap between the stator support 4 and the shell 8, that is, the axial gap between the stator and the rotor of the to-be-adjusted inductance encoder 10, so as to improve the precision of the to-be-adjusted inductance encoder 10; the electrical compensation instruction is obtained by the error compensation algorithm on the basis of the mechanical adjustment instruction.

[0074] In the embodiment, the axial gap adjusting device is a plurality of gaskets with different thicknesses (such as 0.01 mm, 0.02 mm, 0.05 mm, etc.) arranged between the stator support 4 and the shell 8. When the axial gap between the rotor and the stator of the to-be-adjusted inductance encoder 10 is changed, only the number of gaskets or the gaskets with different thicknesses need to be added or replaced.

[0075] In use, the rotor of the to-be-adjusted inductance encoder 10 is installed on the upper end of the turntable 5, so as to ensure that the rotor of the to-be-adjusted inductance encoder 10 coincides with the rotation axis of the turntable 5; then the stator of the to-be-adjusted inductance encoder 10 is fixed on the upper end of the stator support 4; the stator support 4 is connected to the shell 8 by the fastener, and the gasket is arranged between the stator support 4 and the shell 8. During the connection of the stator support 4 and the shell 8, the lever micrometer is used to make the stator support 4, so that the rotation axes of the stator and the rotor of the to-be-adjusted inductance encoder 10 coincide together, so as to complete the assembly of the to-be-adjusted inductance encoder 10; then the host computer 3 edits and sends the control instruction to the turntable controller 2, the turntable controller 2 drives the turntable 6 to rotate, and the rotor of the to-be-adjusted inductance encoder 10 rotates synchronously with the turntable 6. At this time, the host computer 3 collects the rotation angle of the turntable 6 and the rotation angle displayed by the to-be-adjusted inductance encoder 10, and generates the mechanical adjustment instruction or the electrical compensation instruction according to the rotation angles of the turntable 6 and the to-be-adjusted inductance encoder 10, which is used for the precision adjustment of the to-be-adjusted inductance encoder 10.

[0076] The assembly process of the inductance encoder precision adjustment device embodiment of the present application is as follows:

[0077] (1) The turntable 6 is fixed on the upper end of the base 7 by screws;

[0078] (2) The shell 8 is covered on the turntable 6, and the lower end of the shell 8 is connected with the base 7;

[0079] (3) Install the rotor of the inductive encoder 10 to be adjusted on the upper end of the turntable 5 so that the rotor of the inductive encoder 10 to be adjusted coincides with the rotation axis of the turntable 5.

[0080] (4) Install the stator of the inductive encoder 10 to be adjusted on the upper end of the stator support 4. During installation, use a lever dial indicator to measure and make the stator of the inductive encoder 10 to be adjusted coincide with the rotation axis of the stator support 4.

[0081] (5) Place a shim between the stator support 4 and the outer casing 8. After the stator support 4 and the rotation axis of the turntable 5 are aligned by a lever dial indicator, use bolts to connect the stator support 4 and the outer casing 8 together.

[0082] (6) Connect the turntable 6 and the turntable controller 2 together with a cable, and connect the turntable controller 2 and the stator of the inductor encoder 10 to be adjusted to the host computer 3 with cables respectively.

[0083] like Figures 6-8 As shown, the accuracy adjustment of the inductive encoder using the aforementioned inductive encoder accuracy adjustment device specifically includes the following steps:

[0084] Assume that the model of the inductive encoder 10 to be adjusted in this embodiment is LISN-25 (rotor radius 25mm); the axial clearance adjustment range between the stator and the rotor is 0.01mm-0.5mm; and the coaxiality error is ≤0.5μm (after calibration with a lever dial indicator).

[0085] Step 1: Hardware Assembly

[0086] Step 1.1: Install the rotor of the inductive encoder (LISN-25) on the upper end of the turntable 5; install the stator of the inductive encoder (LISN-25) on the upper end of the stator support 4.

[0087] Step 1.2: Install the stator support 4 onto the upper end of the housing 8, and set an axial clearance adjustment device between the stator support 4 and the housing 8. At the same time, use a coaxiality detection device (such as a laser interferometer with a calibration accuracy ≤0.5μm) to adjust the coaxiality between the stator support 4 and the turntable 5. After the adjustment is completed, lock the stator support 4 onto the upper end of the housing 8.

[0088] Step 2, Mechanical Adjustment

[0089] Step 2.1: Control the turntable controller 2 through the host computer 3 to drive the turntable 6 to rotate, and collect the rotation angle θ1 of the turntable 6.

[0090] Step 2.2: The host computer 3 collects the rotation angle θ2 output by the inductive encoder (LISN-25) through the signal output terminal on the stator of the inductive encoder (LISN-25).

[0091] Step 2.3, Calculate the angle deviation Δθ c : Angle deviation Δθ c The angle deviation Δθ is calculated by subtracting the rotation angle θ2 outputted by the inductance encoder (LISN-25) from the rotation angle θ1 of the turntable 6, i.e. Δθ = θ1- θ2. c

[0092] Step 2.4, Adjust the axial gap between the rotor and the stator of the inductance encoder (LISN-25) according to the angle deviation Δθ c Adjust the axial gap between the rotor and the stator of the inductance encoder (LISN-25) through the axial gap adjustment device (multiple shims).

[0093] Step 2.5, Repeat steps 2.1-2.4 until the angle deviation Δθ c no longer decreases, i.e. the minimum value of the angle deviation that can be effectively eliminated by the axial gap between the stator and the rotor of the inductance encoder (LISN-25), then record the angle deviation Δθ c that no longer decreases as the minimum value of the angle deviation that can be reduced by the axial gap adjustment device. cmin (i.e. when the angle deviation Δθ c is greater than this value, the deviation is mainly caused by mechanical installation errors such as stator and rotor eccentricity, improper axial gap, which needs to be corrected by mechanical adjustment; when Δθ c is less than or equal to this value, the deviation is mainly caused by electrical errors of the encoder itself such as signal harmonic distortion, which needs to be compensated by algorithm); and record the mechanical adjustment data at this time, i.e. the axial gap L between the stator and the rotor of the inductance encoder (LISN-25); the distance of the axial gap L is measured by a length measuring tool (such as a vernier caliper).

[0094] Experiments show that: when the angle deviation Δθ c > 0.1°, the precision of the inductance encoder (LISN-25) can be adjusted by increasing or decreasing the number of shims; when the angle deviation Δθ c ≤ 0.1°, mechanical adjustment will fail, i.e. increasing or decreasing the number of shims will not affect the precision of the inductance encoder (LISN-25).

[0095] Therefore, the axial gap L between the stator and the rotor of the inductance encoder of the inductance encoder (LISN-25) at Δθ c = 0.1° is the optimal solution of the axial gap between the two, and the length of L measured by the vernier caliper is 0.08 mm, then the axial gap between the stator and the rotor of the inductance encoder (LISN-25) should be set to 0.08 mm when installing the inductance encoder of the inductance encoder (LISN-25) model.

[0096] Step 3, Electrical compensation

[0097] ​Step 3.1, the host computer 3 controls the turntable controller 2 to drive the turntable 6 to rotate, and the host computer 3 collects at multiple sampling points:

[0098] The rotation angle θ of the turntable 6 t ;

[0099] And the rotation angle θ output by the inductance encoder (LISN-25) e .

[0100] Step 3.2, calculate the angle deviation Δθ at each sampling point: the angle deviation Δθ is obtained by subtracting the rotation angle θ output by the inductance encoder (LISN-25) from the rotation angle θ of the turntable 6 t , that is, Δθ = θ e - θ t . e .

[0101] Step 3.3, generate electrical compensation instructions based on the angle sampling point Δθ, including:

[0102] a) Construct a periodic error compensation model;

[0103] b) Solve the model compensation coefficient;

[0104] c) Generate a feasible compensation coefficient, and input the electrical compensation instructions including the compensation coefficient into the inductance encoder (LISN-25) through the host computer 3, adjust the parameters of the inductance encoder (LISN-25) to compensate for the angle deviation;

[0105] Preferably, the electrical compensation instruction is a periodic error compensation algorithm based on harmonic analysis.

[0106] The error compensation algorithm is constructed by the following steps:

[0107] a) Set the sampling points in step 3.1 to 1080, and establish a data set according to the angle deviation collected from 1080 sampling points: {Δθ i , θ ei}(i = 1, 2, …, 1080) wherein Δθ i is the angle deviation value, and θ ei is the rotation angle output by the inductance encoder 10 to be adjusted and measured;

[0108] At the same time, a Fourier series error model is established: Let N be 5, then the harmonic stage is 5th order, a0, a k , b k are the coefficients to be solved;

[0109] b) Solve the Fourier series error model coefficient by least square method;

[0110] The minimization objective function is:

[0111] A design matrix X is constructed, which consists of 1080 rows and 11 columns, and each row element is: [1, cosθ i , sinθ i , cos2θ i , sin2θ i , …, cos5θ i , sin5θ i ];

[0112] An observation vector Y is constructed: Y = [Δθ1, Δθ2, …, Δθ 1080 ] T ;

[0113] The coefficient vector β is solved by the normal equation: X T Xβ = X T Y;

[0114] Since N = 5, the minimum coefficient combination is obtained: [a0, a1, b1, a2, b2, a3, b3, a4, b4, a5, b5] T ;

[0115] c) The obtained minimum coefficient combination [a0, a1, b1, a2, …, a5, b5] T is input into the inductance encoder (LISN-25) through the host computer 3, and the parameters of the inductance encoder (LISN-25) are adjusted to compensate for the angle deviation.

[0116] Step 3.4, error verification

[0117] Repeat steps 3.1-3.3 until the angle deviation Δθ ≤ the preset target accuracy, then the electrical compensation instruction in step 3.3 is burned into the memory of the inductance encoder (LISN-25) as compensation data; When the inductance encoder (LISN-25) works normally subsequently, its internal processor (MCU) will call the error compensation instruction (error compensation algorithm, i.e. error curve function) stored in the memory after reading the original angle signal. The final output high-precision angle value is obtained by using the current output original angle value plus the estimated error compensation value of the angle point, so as to compensate the inherent electrical error of the inductance encoder (LISN-25) in real time.

[0118] Step 4, production reuse of test data

[0119] The mechanical adjustment data recorded in step 2.5 is used as a guide to adjust the axial gap L between the stator and the rotor of the same type of inductance encoder during the production assembly, and the compensation data obtained in step 3.4 is used as compensation data burned into the memory of the same type of inductance encoder during the production assembly, so as to realize the accuracy optimization of the inductance encoder.

[0120] The above takes the LISN-25 type inductance encoder as an example to illustrate the accuracy adjustment of the inductance encoder by the inductance encoder accuracy adjustment device, and the inductance encoder accuracy adjustment device and the method of adjusting the accuracy of the inductance encoder using the device, which is not only used for the LISN-25 type inductance encoder.

[0121] Before the actual production and assembly of other types of inductance encoders, only one inductance encoder of the same type is needed to simulate the adjustment process using the inductance encoder accuracy adjustment device of the present application, so as to record the optimal axial gap L between the stator and the rotor of the inductance encoder according to the process of step 2 of the inductance encoder accuracy adjustment method of the present application, and generate the electrical compensation instruction of the type according to the process of step 3 of the inductance encoder accuracy adjustment method of the present application, and burn the electrical compensation instruction into the memory of the inductance encoder of the same type, so as to complete the accuracy adjustment of the inductance encoder of the same type.

[0122] Finally, it should be pointed out that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. An inductance encoder precision calibration device, characterized by, The application relates to an inductance encoder precision adjustment device. The device comprises a rotary table controller (2), an upper computer (3) and a base (7). The base (7) is provided with a rotary table (6) and a shell (8) outside the rotary table (6); the shell (8) is provided with a stator support (4) outside the output end of the rotary table (6); and the output end of the rotary table (6) is provided with a rotating disc (5) used for connecting a rotor of the inductance encoder (10) to be adjusted and measured. The rotary table controller (2) is electrically connected with the control end of the rotary table (6) and is used for controlling the rotation angle of the output end of the rotary table (6); and the rotary table controller (2) is electrically connected with the upper computer (3) and is used for transmitting the rotation angle information of the output end of the rotary table (6) to the upper computer (3). The stator support (4) is used for fixing the stator of the inductance encoder (10) to be adjusted and measured; and an axial gap adjusting device is arranged between the stator support (4) and the shell (8) and is used for adjusting the axial gap between the stator and the rotor of the inductance encoder (10) to be adjusted and measured. The upper computer (3) is electrically connected with the signal output end on the stator of the inductance encoder (10) to be adjusted and measured. The upper computer (3) is used for controlling the rotary table controller (2) to drive the rotary table (6) to rotate, collecting the rotation angles output by the rotary table (6) and the inductance encoder (10) to be adjusted and measured and performing comparative analysis, generating and displaying precision adjustment instructions, adjusting the inductance encoder (10) to be adjusted and measured according to the precision adjustment instructions, so that the precision of the inductance encoder (10) to be adjusted and measured reaches the preset requirement, and then the adjustment parameters of the inductance encoder (10) to be adjusted and measured are obtained.

2. The inductance encoder precision adjustment device according to claim 1, wherein the axial gap adjusting device is a plurality of gaskets or telescopic sleeves with different thicknesses, which are used for adjusting the axial distance between the stator support (4) and the shell (8) to adjust the axial gap between the stator and the rotor of the inductance encoder (10) to be adjusted and measured, and then adjust the precision of the inductance encoder (10) to be adjusted and measured.

3. The inductance encoder precision adjustment device according to claim 2, wherein the upper end of the rotating disc (5) is provided with a mounting blind hole matched with the shape of the rotor of the inductance encoder (10) to be adjusted and measured, which is used for mounting the rotor of the inductance encoder (10) to be adjusted and measured through the hole shaft cooperation of the H7 / g6 tolerance level.

4. The inductance encoder precision adjustment device according to claim 3, wherein the coaxiality deviation of the stator support (4) and the rotating disc (5) should be less than or equal to 0.5 microns.

5. The inductance encoder precision adjustment device according to claim 4, wherein the stator support (4) and the shell (8) are connected through a flange plate, the flange plate is provided with a through hole, the diameter of the through hole is greater than the diameter of the connecting piece between the stator support (4) and the shell (8), and the flange plate is used for adjusting the coaxiality of the stator support (4) and the rotating disc (5).

6. The inductance encoder precision adjustment device according to claim 1, wherein the rotation precision of the rotary table (6) is less than or equal to 0.001 degrees. The application further discloses a method for adjusting and measuring the precision of an inductance encoder. Step 1, hardware assembly ​ ​ ​ 7. A method for calibrating the accuracy of an inductance encoder, using the inductance encoder accuracy calibration device according to any one of claims 1 to 6, characterized in that, ​ ​ 1.1, install the rotor of the inductance encoder to be tested (10) on the upper end of the rotating disc (5); install the stator of the inductance encoder to be tested (10) on the upper end of the stator support (4); 1.2, install the stator support (4) to the upper end of the shell (8), and set the axial gap adjusting device between the two, at the same time, use the coaxial detection device to adjust the coaxiality of the stator support (4) and the rotating disc (5), and after the adjustment is completed, lock the stator support (4) on the upper end of the shell (8); Step 2, mechanical adjustment 2.1, control the rotating table controller (2) to drive the rotating table (6) to rotate through the upper computer (3), and collect the rotation angle θ1 of the rotating table (6); 2.2, collect the rotation angle θ2 output by the inductance encoder to be tested (10) through the signal output end on the stator of the inductance encoder to be tested (10) by the upper computer (3); 2.3, Calculate the angular deviation Δθ c = θ1- θ2; 2.4、 According to the angle deviation Δθ c adjusting the axial gap between the rotor and the stator of the inductance encoder (10) to be tested by the axial gap adjusting device; 2.5, repeat steps 2.1-2.4 until the angle deviation Δθ c If the angle deviation Δθ does not decrease any more, the angle deviation Δθ is recorded as the minimum value Δθ c which the angle deviation can be reduced by the axial gap adjustment device cmin ; and the mechanical calibration data at this time, i.e. the axial gap L between the stator and the rotor of the inductance encoder (10) to be calibrated, is recorded. Step 3, electrical compensation 3.1, control the rotating table controller (2) to drive the rotating table (6) to rotate through the upper computer (3), and the upper computer (3) collects at multiple sampling points: Rotation angle Θ of the turntable (6) t ; and the rotation angle θ outputted by the to-be-tested inductive encoder (10) e ; 3.2, calculate the angle deviation Δθ = θ t -θ e ; 3.3, generate electrical compensation instructions based on the angle sampling points Δθ, including: a) constructing a periodic error compensation model; b) solving the model compensation coefficient; c) generating a feasible compensation coefficient, and inputting the electrical compensation instructions including the compensation coefficient into the inductance encoder to be tested (10) through the upper computer (3), adjusting the parameters of the inductance encoder to be tested (10) to compensate for the angle deviation; 3.4, error verification Repeat steps 3.1-3.3 until the angle deviation Δθ≤the preset target accuracy, then the electrical compensation instructions in step 3.3 are taken as the compensation data burned into the memory of the inductance encoder to be tested (10); Step 4, production reuse of adjustment data The mechanical adjustment data recorded in step 2.5 is used as the guide axial gap L of the stator and the rotor during the assembly of the same type of inductance encoder for mass production, and the compensation data obtained in step 3.4 is used as the compensation data burned into the memory of the same type of inductance encoder during the assembly for mass production, so as to realize the adjustment of the inductance encoder precision optimization.

8. The inductance encoder precision adjustment method according to claim 7, wherein the electrical compensation instructions in step 3.3 are periodic error compensation algorithms based on harmonic analysis.

9. The inductance encoder precision adjustment method according to claim 8, wherein the error compensation algorithm in step 3.3 is constructed by the following steps: b) solving the Fourier series error model coefficient by the least square method; 10. The inductance encoder precision adjustment method according to claim 7, wherein the distance of the axial gap L in step 2.5 is measured by a length measuring tool; a) Establish a dataset using the angular deviations collected from multiple sampling points in step 3.1: {Δθ i θ ei }(i=1,2,…,m)where Δθ i Let θ be the angular deviation value. ei The rotation angle output by the inductive encoder (10) to be adjusted; At the same time, the Fourier series error model is established: Where N is the harmonic order, a0, a k , b k are the coefficients to be solved; The length measuring tool is a measuring instrument with an accuracy of ≥0.01 mm. The minimization objective function is: The minimum system combination is obtained as [a0, a1, b1,..., a N , b N ] T ; c) combining the obtained minimum coefficient set [a0, a1, b1,..., a N , b N ] T Through the host computer (3) input to the inductance encoder (10) to be adjusted, adjust the parameters of the inductance encoder (10) to be adjusted to compensate for the angle deviation. ​ ​ ​

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