A fast calibration method for non-contact two-dimensional angle measurement

Abstract

The application provides a kind of non-contact two-dimensional angle measurement fast calibration method, comprising: step 1, the shell of the equipment to be calibrated is fixed horizontally on the platform;Step 2, collect the inertial data output by the inertial measurement unit and the electrical signal data output by two two-dimensional angle measurement;Step 3, process the acquired data to obtain the deflection angle, and determine the best corresponding relationship between the angle measurement signal and the deflection angle;Step 4, zero correction is carried out on the best corresponding relationship to obtain the final calibration relationship;After the conditions described in the patent are met, after using the method, the acquisition of tens of thousands of calibration data to the acquisition of calibration results only needs five to ten minutes, and one to two groups of unprocessed data can be obtained in the corresponding time by using the conventional method.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic equipment technology, and in particular to a rapid calibration method for non-contact two-dimensional angle measurement. Background Technology

[0002] Patent "US005897223" employs a non-contact two-dimensional angle measurement method in the inner frame of a five-axis photoelectric stabilization platform. Compared to traditional angle measurement methods, this method can measure the relative motion of the rotor to the stator along the assembly spherical surface in any direction within its range. Traditional angle measurement methods (grating encoders, capacitor encoders, electromagnetic encoders) can only measure the coaxial rotation angle of the stator relative to the rotor along the sleeve axis. This solution uses a combination of two two-dimensional angle measurement methods to measure the angle of the inner frame's three-degree-of-freedom fixed-point rotation relative to the inner wall of the outer frame along the center of the outer frame, thereby enabling the control of the inner frame's azimuth, pitch, and roll angles.

[0003] Since the angle measurement principle provides an electrical signal, it needs to be converted into an angle value. Because the electrical characteristics of the angle measurement itself cannot be guaranteed to be consistent across all units, and due to installation errors, it is difficult to directly obtain the correspondence between the electrical signal and the angle value through methods such as principle derivation; calibration is required. Specifically, the existing technology still has the following problems:

[0004] 1) Since the inner shell can rotate relative to the outer shell at three angles, the normals of the two reflecting planes must be taken to determine the three angles. For each set of angle positions, the angle between the normals of the two planes in the established reference must be measured.

[0005] 2) Because it is necessary to attach a hexahedron or two plane mirrors to the inner shell to measure the surface normal of the mirror at different angles between the inner shells, it is also necessary to calibrate the positional error introduced by the attachment, which increases the workload. At the same time, due to the excessive manpower involved, errors are prone to occur.

[0006] 3) Since the photoelectric theodolite alignment operation is required, each target position needs to be held for a sufficient time to ensure this. This holding requires the design of a special structural clamping device, which may not be feasible in actual operation due to the limitation of structural space. Summary of the Invention

[0007] This invention provides a non-contact, rapid calibration method for two-dimensional angle measurement. After the method is coded, only the measurement data needs to be provided to automatically find the correspondence expression between the angle and the two-dimensional angle measurement electrical signal.

[0008] Specifically, this invention proposes a rapid calibration method for non-contact two-dimensional angle measurement. In the rapid calibration method for non-contact two-dimensional angle measurement, the mover and stator to be calibrated are respectively installed on the inner and outer shells and fixed to the inner and outer shells. The outer shell is fixed to the rotation center, and the inner shell rotates at a fixed point within a limited range around the rotation center, so that the inner shell rotates with three degrees of freedom relative to the outer shell. The inertial measurement unit is fixed to the inner shell and rotates with the rotation of the inner shell.

[0009] The non-contact two-dimensional angle measurement rapid calibration method includes the following steps:

[0010] Step 1: Horizontally fix the outer casing of the device to be calibrated on the platform;

[0011] Step 2: Collect the inertial data output by the inertial measurement unit and the electrical signal data output by the two two-dimensional angle measurement units;

[0012] There are four sets of angle measurement signals, including two two-dimensional angle measurement AD voltage signals, and three sets of data corresponding to the azimuth, pitch, and roll information output by the inertial measurement unit during the process.

[0013] Step 3: Process the acquired data to obtain the deflection angle and determine the optimal correspondence between the angle measurement signal and the deflection angle;

[0014] Step 4: Perform zero-point correction on the best correspondence to obtain the final calibration relationship;

[0015] Step 3 also includes the following steps:

[0016] Step 31: Label the acquired data;

[0017] Step 32: Convert the data output by the inertial measurement unit into Euler attitude angles relative to the initial zero position;

[0018] Step 33: Calculate the deflection angle during calibration;

[0019] The deflection angle includes the azimuth, pitch, and roll angles of the fixed-point rotation relative to the initial zero position.

[0020] Step 34: Establish the relationship between the azimuth, pitch, and roll angles of the fixed-point rotation relative to the initial zero position and the four sets of voltages;

[0021] Step 35: Based on the fitting error, determine the optimal correspondence between the four sets of angle measurement signals and the deflection angle.

[0022] Furthermore, in step 1, when the outer shell is placed horizontally and the inner shell is in the zero position relative to the outer shell, the angle between the line connecting the two angle measuring rotors and the rotation center and the horizontal line is 45 degrees, and the plane formed by the line connecting the two angle measuring rotors and the rotation center is theoretically within the plumb plane.

[0023] Furthermore, the inner shell can rotate freely relative to the outer shell within the range of two-dimensional angular travel.

[0024] Furthermore, in step 32, when the inertial measurement unit outputs angular rate information, the relationship between the Euler attitude angle and the recorded gyroscope rate output by the inertial measurement unit is as follows:

[0025]

[0026] Where φ1 represents the roll angle, θ1 represents the pitch angle, ψ1 represents the azimuth angle, p represents the output roll angular velocity, q represents the output pitch angular velocity, and r represents the output heading angular velocity.

[0027] Furthermore, in step 32, when the inertial measurement unit outputs inertial attitude angle information, the relationship between the Euler attitude angle and the recorded gyroscope rate output by the inertial measurement unit is as follows:

[0028]

[0029] a1=cosθ0(0)

[0030] a2=cosψ0(0)

[0031] a3=cosφ0(0)

[0032] a4=sinψ0(0)

[0033] a5=sinθ0(0)

[0034] a6=sinφ0(0)

[0035]

[0036] b1 = cosθ0(t)

[0037] b2 = cosψ0(t)

[0038] b3 = cosφ0(t)

[0039] b4=sinψ0(t)

[0040] b5 = sinθ0(t)

[0041] b6 = sinφ0(t)

[0042] C = B T *A

[0043]

[0044] φ0(0), θ0(0), and ψ0(0) represent the initial values ​​of roll angle φ0, pitch angle θ0, and azimuth angle ψ0 in the attitude angle data output by the inertial measurement unit (IMU) at the start of the calibration experiment, respectively; φ0(t), θ0(t), and ψ0(t) represent the sampled values ​​of roll angle φ0, pitch angle θ0, and azimuth angle ψ0 in the attitude angle data output by the IMU at time t after the start of the calibration experiment, respectively; C(i,j) represents the element in the i-th row and j-th column of matrix C; A is the transformation matrix between the IMU's own coordinate system and the inertial coordinate system obtained based on the IMU data at the start of the calibration experiment, and a1...a6 are respectively... The coordinates of the pitch angle at the start of calibration are: A, B, C, D, and E. The transformation matrix between the inertial measurement unit's own coordinate system and the inertial coordinate system obtained from the inertial measurement unit data during the calibration test. B1...b6 are the coordinate transformation matrices of the pitch angle, azimuth angle, roll angle, azimuth angle, pitch angle, and roll angle during the calibration process, respectively. C is the coordinate transformation matrix of the inertial navigation system relative to the initial calibration time during the calibration process.

[0045] Furthermore, in step 33, the roll angle φ1, pitch angle θ1, and azimuth angle ψ1 of the Euler attitude angles relative to the initial zero position are converted into the azimuth angle θ of the rotation around the initial zero position fixed point. a Pitch angle θ e Roll angle θ r :

[0046]

[0047]

[0048] Where, θ a θ represents the azimuth angle of rotation about the initial zero position fixed point. e θ represents the pitch angle of rotation about the initial zero position. r θ represents the roll angle of rotation about the initial zero fixed point. iner k represents the absolute value of the angle vector representing rotation about the initial zero fixed point. xz For the sake of convenience in formula expression, x, y, and z are the x, y, and z coordinates of the unit vector of the angle vector of rotation relative to the initial zero fixed point.

[0049] Furthermore, in step 34, under ideal installation conditions, the azimuth, pitch, and roll angles of the inner housing relative to the initial zero position and the corresponding angle measurement voltages have the following correspondence:

[0050]

[0051] In the formula, v 11 v 12 This represents the two readings of the first angle measurement, v 21 v 22 These represent the two readings of the second angle measurement.

[0052] Furthermore, considering the actual materialization errors in the actual process, the relationship between the azimuth, pitch, and roll angles of the actual inner shell's fixed-point rotation relative to the initial zero position and the corresponding angle measurement voltage is as follows:

[0053]

[0054] In the formula, α 11 α 12 α 21 α 22 To account for actual materialization errors, the inner shell rotates around the initial zero-position fixed point by an angle θ. a θ e θ r The linear combination of the linear error matrix between the two readings of the first angle measurement; β 11 β 12 β 21 β 22 To account for actual materialization errors, the rotation angle θ around the initial zero position fixed point is considered. a θ e θ r The linear error matrix between the linear combination of the two readings of the second angle measurement and the linear combination of the two readings; v 11_0 v 12_0 v 21_0 v 22_0 This indicates the offset error of the angle measurement reading introduced by the actual materialization error.

[0055] Furthermore, in step 34, the relationship between the azimuth, pitch, and roll angles of the actual inner shell relative to the initial zero position and the corresponding angle measurement voltage is inverted:

[0056]

[0057] Based on the calculated θ a θ e θ r With the measured v 11 v 12 v21 v 22 The value of A can be obtained through a fitting method. 11 A 12 A 21 A 22 θ 11_0 θ 12_0 B 11 B 12 B 21 B 22 θ 21_0 θ 22_0 .

[0058] A 11 A 12 A 21 A 22 The first two angle readings are used to measure the angle θ of the inner shell rotating around the initial zero point. a θ e θ r The elements of the linear error matrix between linear combinations, θ 11_0 and θ 12_0 This is the zero-position error in angle measurement caused by the bias error of the first angle measurement reading;

[0059] Based on the same principle, calculate B. 11 B 12 B 21 B 22 The two readings of the second angle measurement are used to rotate the inner shell around the initial zero-position fixed point by the angle θ. a θ e θ r The elements of the linear error matrix between linear combinations; θ 21_0 and θ 22_0 This is the zero-position error in angle measurement caused by the bias error of the second angle measurement reading;

[0060] The calibration results between the electrical signal of the angle measurement and the corresponding angle obtained in this embodiment are shown below:

[0061]

[0062] ζ1 represents the first weighting coefficient, and ζ2 represents the second weighting coefficient.

[0063] The beneficial effects achieved by this invention are:

[0064] The calibration principle of the rapid calibration method proposed in this invention can realize online or offline calibration of non-contact two-dimensional angle measurement. After adopting this method, it only takes five to ten minutes to collect tens of thousands of sets of calibration data and obtain the calibration results, which saves a lot of time compared with the calibration process of existing technology that is calculated by day.

[0065] The rapid calibration method proposed in this invention provides the calibration principle for non-contact two-dimensional angle measurement. When the inner shell is rotated relative to the outer shell by servo means, online calibration of two-dimensional angle measurement can be achieved.

[0066] The rapid calibration method proposed in this invention is convenient for data acquisition, can achieve full traversal of the angular measurement positions, and can obtain the optimal calibration results under the corresponding error principle;

[0067] The rapid calibration method proposed in this invention does not require disassembling or replacing equipment or using other measuring instruments (autocollimator, theodolite, gyrotheodolite, etc.), thus avoiding the introduction of secondary assembly and adjustment errors or complex data processing. Attached Figure Description

[0068] Figure 1 A schematic diagram illustrating the implementation environment of a rapid calibration method for non-contact two-dimensional angle measurement provided in an embodiment of the present invention;

[0069] Figure 2 A schematic diagram of an embodiment of a rapid calibration method for non-contact two-dimensional angle measurement provided by an embodiment of the present invention;

[0070] Figure 3 This is a flowchart illustrating a rapid calibration method for non-contact two-dimensional angle measurement provided in an embodiment of the present invention. Detailed Implementation

[0071] The technical solution of the present invention will be described in more detail below with reference to the accompanying drawings. The present invention includes, but is not limited to, the following embodiments.

[0072] The calibration method provided by this invention is essentially a process of obtaining calibration results by using a corresponding algorithm after acquiring data through a specific operation. The final data processing step is generally implemented through software code to improve efficiency and reduce labor costs. However, in cases where software code cannot be used, it can still be completed through a large amount of manual calculation. The implementation examples and descriptions below assume that this calibration method can be coded.

[0073] Example 1

[0074] As attached Figure 2As shown, the two-dimensional angular measuring mover and stator required for calibration in this invention are respectively mounted on the inner and outer shells and fixedly connected to them. The outer shell (represented by a black dashed circle) is fixedly connected to the rotation center (described by a black solid circle in the figure), and the inner shell (represented by a red solid circle in the figure) can rotate at a fixed point within a finite range around the rotation center, thus allowing the inner shell to rotate with three degrees of freedom relative to the outer shell. In addition to the angular measuring mover being fixed to the inner shell, the IMU (Inertial Measurement Unit) is also fixed to the inner shell and rotates with the inner shell. Furthermore, when the outer shell is placed horizontally and the inner shell is in the zero position relative to the outer shell, the angle between the lines connecting the two angular measuring movers and the rotation center and the horizontal line is 45 degrees, and the plane formed by the lines connecting the two angular measuring movers and the rotation center is theoretically within a vertical plane.

[0075] As attached Figure 3 As shown, the non-contact two-dimensional angle measurement rapid calibration method provided by the present invention includes the following steps:

[0076] Step 1: Horizontally fix the outer casing of the device to be calibrated on the platform;

[0077] Place the power-enabled device horizontally on a fixed platform to confirm it is powered on and can acquire two-dimensional angle measurement readings and IMU data. Two-dimensional angle measurement readings are typically voltage signals acquired by an analog-to-digital converter (ADC), with two voltage signals for each angle measurement. IMU readings are usually provided via serial port. Depending on the required calibration accuracy, from low to high, you can choose a MEMS IMU followed by a fiber optic / laser gyroscope IMU. Based on experience, a fiber optic IMU is recommended.

[0078] The outer casing is fixed or locked using mechanical or servo-based methods, keeping it constant relative to the equipment base and fixed platform. Simultaneously, the inner casing can rotate freely relative to the outer casing within its two-dimensional angular travel range.

[0079] Step 2: Collect the inertial data output by the inertial measurement unit and the electrical signal data output by the two two-dimensional angle measurement units;

[0080] Turn on the device's data acquisition system and acquire the inertial data output by the IMU and the electrical signal data output by the two two-dimensional angle measurement devices at the same time reference. It is recommended that the data acquisition frequency be higher than 500Hz, and 1000Hz is recommended.

[0081] With the inner housing held near the zero position (this position is denoted as the initial zero position, and will be described as such in the following text), slowly rotate the inner housing manually (offline calibration) or by other means (servo motor means) to make it slowly rotate back and forth relative to the outer housing in the azimuth direction specified by the IMU, covering the mechanical travel in the azimuth direction 1 to 2 times or more within a time range of approximately 2 to 4 seconds. After completing this, return to the vicinity of the zero position, and then rotate sequentially in the pitch and roll directions specified by the IMU. After rotating in the roll direction and returning to the vicinity of the zero position, allow the inner housing to rotate freely within the mechanical travel range.

[0082] To avoid the effects of gyroscope drift and Earth's rotation, the entire calibration operation takes approximately 16 to 20 seconds to complete, saving the data from the device's data acquisition system.

[0083] Export the two-dimensional angle measurement data and IMU data under the same time reference during the calibration operation. In this example, a total of 7 sets of data are obtained, including 4 sets of angle measurement signals from the two two-dimensional angle measurement AD voltage signals, and 3 sets of data corresponding to the azimuth, pitch, and roll information output by the IMU during the process.

[0084] Step 3: Process the acquired data to determine the optimal correspondence between the angle measurement signal and the deflection angle;

[0085] Specifically, it also includes the following steps:

[0086] Step 31: Label the acquired data to facilitate subsequent processing descriptions.

[0087] First, number the four sets of angle measurement AD voltage data as 1 to 4, denoted as V1, V2, V3, and V4. If the IMU outputs angle information, record the angle data as φ0.

[0088] (Roll angle), θ0 (Pitch angle), ψ0 (Azimuth angle). If the IMU outputs angular velocity information, then the output roll angular velocity, pitch angular velocity, and yaw angular velocity are recorded as p, q, and r.

[0089] Step 32: Obtain the Euler attitude angle relative to the initial zero position;

[0090] Then, using the initial zero position as the zero point, the data output by the IMU is converted into Euler attitude angles relative to the initial zero position. There are two cases at this point, and the acquisition of Euler attitude angles relative to the initial zero position in each case is described below.

[0091] Scenario 1: When the IMU outputs angular rate information, the relationship between the Euler attitude angles φ1 (roll angle), θ1 (pitch angle), and ψ1 (azimuth angle) expected in this step and the recorded gyroscope rate output by the IMU is shown below. Discretizing the following equation yields the result. During the solution process, the initial values ​​of φ1, θ1, and ψ1 are set to 0.

[0092]

[0093] Scenario 2: When the IMU outputs inertial attitude angle information, the recorded real-time IMU output attitude angle data φ0 (roll angle), θ0 (pitch angle), ψ0 (azimuth angle) have the following relationship with the Euler attitude angles φ1 (roll angle), θ1 (pitch angle), ψ1 (azimuth angle) expected to be obtained in this step relative to the initial zero position:

[0094]

[0095] a1=cosθ0(0)

[0096] a2=cosψ0(0)

[0097] a3=cosφ0(0)

[0098] a4=sinψ0(0)

[0099] a5=sinθ0(0)

[0100] a6=sinφ0(0) (Equation 3)

[0101]

[0102] b1 = cosθ0(t)

[0103] b2 = cosψ0(t)

[0104] b3 = cosφ0(t)

[0105] b4=sinψ0(t)

[0106] b5 = sinθ0(t)

[0107] b6=sinφ0(t) (Equation 5)

[0108] C = B T *A (Equation 6)

[0109]

[0110] In the above set of formulas (Equations 2 to 7), φ0(0), θ0(0), and ψ0(0) represent the initial values ​​of the attitude angle data φ0 (roll angle), θ0 (pitch angle), and ψ0 (azimuth angle) output by the IMU in real time at the beginning of the calibration experiment; φ0(t), θ0(t), and ψ0(t) represent the sampled values ​​of the attitude angle data φ0 (roll angle), θ0 (pitch angle), and ψ0 (azimuth angle) output by the IMU in real time at time t after the start of the calibration experiment; C(i,j) represents the element in the i-th row and j-th column of matrix C.

[0111] Step 33: Calculate the deflection angle during calibration;

[0112] The yaw angle includes the azimuth, pitch, and roll angles of the fixed-point rotation relative to the initial zero position.

[0113] The Euler attitude angles φ1, θ1, and ψ1 obtained above relative to the initial zero position are converted into azimuth angles θ of rotation around the initial zero position fixed point. a Pitch angle θ e Roll angle θ r .

[0114]

[0115] In the formula, θ iner x, y, z are uniquely determined by φ1, θ1, ψ1, and their solution methods are shown in equations 9 to 11 below.

[0116]

[0117] Step 34: Establish the relationship between the azimuth, pitch, and roll angles of the fixed-point rotation relative to the initial zero position and the four sets of voltages;

[0118] In this embodiment, under ideal installation conditions, the azimuth, pitch, and roll angles of the inner housing relative to the initial zero position have the following correspondence with the corresponding angle measurement voltages:

[0119]

[0120] In the formula, v 11 v 12 Indicating ideal installation conditions Figure 2 The two readings of the upper-middle angle (hereinafter referred to as the first angle measurement), v 21 v 22 Indicating ideal installation conditions Figure 2 The two readings of the lower-middle angle (hereinafter referred to as the second angle). θ a θ e θ r The azimuth, pitch, and roll angles represent the rotation around the initial zero position fixed point, which are obtained by solving Equation 8.

[0121] Considering the actual installation error, the inconsistency of the scaling factor between the two-dimensional angle measurement voltage and the angle, the AD voltage bias, and the perpendicularity error of the two-dimensional angle measurement stator crosshair (these errors are collectively referred to as actual materialized errors below), the actual azimuth, pitch, and roll angles of the fixed-point rotation of the inner shell relative to the initial zero position have the following correspondence with the corresponding angle measurement voltage.

[0122]

[0123] In the formula, α 11 α 12 α 21 α 22 To account for actual materialization errors, the voltages in the two directions obtained from the first angle measurement are related to the rotation angle θ of the inner shell around the initial zero-position fixed point. a θ e θ r The linear error matrix between linear combinations; β 11 β 12 β 21 β 22 The voltages in two directions obtained from the second angle measurement after considering actual materialization errors are related to the rotation angle θ around the initial zero-position fixed point. a θ e θ r The linear error matrix between linear combinations; v 11_0 v 12_0 v 21_0 v 22_0 This indicates the zero-position offset error introduced by the actual materialization error.

[0124] Inverting Equation 11 yields the result from the angle measurement voltage to the rotation angle θ. a θ e θ r The model expression between:

[0125]

[0126] The above equation is rearranged, and the corresponding matrix elements are represented by new symbols for easier expression, as shown in Equation 13 below.

[0127]

[0128] Based on the calculated θ a θ e θ r With the measured v 11 v 12 v 21 v 22The corresponding matrix coefficients and zero-digit values ​​can be obtained through fitting methods. A common fitting method is the least squares method, and this implementation example shows the calculation of A using the least squares method. 11 A 12 A 21 A 22 θ 11_0 θ 12_0 The method.

[0129] The corresponding equations are rewritten in standard form using the least squares method, as shown below.

[0130]

[0131] In the formula, θ a (k), θ e (k), θ r (k) represents the angle of rotation of the inner shell relative to the initial zero-position fixed point at time k, obtained from the solution. 11 (k), v 12 (k) represents the electrical signal values ​​of the two channels of the first angle measurement obtained at time k.

[0132] Equation 14 can be simplified to the form shown below.

[0133]

[0134] The least squares estimates of the corresponding parameters are as follows:

[0135]

[0136] Based on the same principle, B can be calculated. 11 B 12 B 21 B 22 θ 21_0 θ 22_0 Coefficient value.

[0137] Finally, the calibration results between the electrical signal of the angle measurement and the corresponding angle in this embodiment are shown below.

[0138]

[0139] It should be noted that since there are 4 input variables and 3 output variables, the expression in Equation 17 is... The scaling result is not unique. ζ1 represents the first weight coefficient and ζ2 represents the second weight coefficient. ζ1 and ζ2 can take any real value. A common value is 0.5 for both.

[0140] Furthermore, the fitting error σ obtained after substituting the above coefficients into the measurement procedure is defined as follows:

[0141]

[0142] Step 35: Based on the fitting error, determine the optimal correspondence between the four sets of angle measurement signals and the deflection angle;

[0143] To complete the calibration of the two-dimensional angle measurement in this implementation example, it is also necessary to confirm the two two-dimensional angle measurement values ​​v in step 54. 11 v 12 v 21 v 22 The correspondence between the four measured values ​​V1, V2, V3, and V4 described in step 51.

[0144] This correspondence can be obtained by writing a program to traverse all correspondences and select the fitting result of the correspondence with the smallest fitting error as the benchmark result.

[0145] Step 4: Perform zero-point correction on the best correspondence to obtain the final calibration relationship;

[0146] Since the initial zero position may be inaccurate during the calibration process, zero position correction is required after the calibration is completed.

[0147] Example 2

[0148] As attached Figure 1 As shown, when the rapid calibration method provided by this invention is applied to the platform in the background art, two two-dimensional angle measuring and inertial measurement units are connected together through a mechanical structure to form the structural basis of the equipment to be calibrated. The angle measuring data and the inertial measurement unit data are transmitted to the host computer software after being aligned with the same time reference through the data acquisition system. The calibration algorithm in this calibration program is run by the host computer software to obtain the correspondence between the two-dimensional angle measuring electrical signal and the rotation angle.

[0149] This invention can be used for the calibration of non-contact two-dimensional angle measurement based on other principles, including but not limited to electromagnetic, inductive, and photoelectric angle measurement. Simultaneously, this method can be used for the calibration of non-contact two-dimensional angle measurement involving relative motion along a spherical surface, including but not limited to ellipsoids, planes, cylinders, and solid surfaces.

[0150] This invention is not limited to the specific embodiments described above. Those skilled in the art can implement this invention using various other specific embodiments based on the disclosed content of the embodiments and accompanying drawings. Therefore, any design that adopts the design structure and concept of this invention and makes some simple changes or modifications falls within the protection scope of this invention.

Claims

1. A rapid calibration method for non-contact two-dimensional angle measurement, wherein the two-dimensional angle measuring mover and stator to be calibrated are respectively mounted on the inner and outer shells and fixedly connected to the inner and outer shells. The outer shell is fixedly connected to the rotation center, and the inner shell rotates at a fixed point within a limited range around the rotation center, thereby the inner shell rotates with three degrees of freedom relative to the outer shell. The inertial measurement unit is fixed on the inner shell and rotates with the inner shell. Its features are, The non-contact two-dimensional angle measurement rapid calibration method includes the following steps: Step 1: Horizontally fix the outer casing of the device to be calibrated on the platform; Step 2: Collect the inertial data output by the inertial measurement unit and the electrical signal data output by the two two-dimensional angle measurement units; There are four sets of angle measurement signals, including two two-dimensional angle measurement AD voltage signals, and three sets of data corresponding to the azimuth, pitch, and roll information output by the inertial measurement unit during the process. Step 3: Process the acquired data to obtain the deflection angle and determine the optimal correspondence between the angle measurement signal and the deflection angle; Step 4: Perform zero-point correction on the best correspondence to obtain the final calibration relationship; Step 3 also includes the following steps: Step 31: Label the acquired data; Step 32: Convert the data output by the inertial measurement unit into Euler attitude angles relative to the initial zero position; Step 33: Calculate the deflection angle during calibration; The deflection angle includes the azimuth, pitch, and roll angles of the fixed-point rotation relative to the initial zero position. Step 34: Establish the relationship between the azimuth, pitch, and roll angles of the fixed-point rotation relative to the initial zero position and the four sets of voltages; Step 35: Based on the fitting error, determine the optimal correspondence between the four sets of angle measurement signals and the deflection angle.

2. The rapid calibration method for non-contact two-dimensional angle measurement according to claim 1, characterized in that, In step 1, when the outer shell is placed horizontally and the inner shell is in the zero position relative to the outer shell, the angle between the line connecting the two angular measuring movers and the rotation center and the horizontal line is 45 degrees, and the plane formed by the line connecting the two angular measuring movers and the rotation center is theoretically within the plumb plane. Furthermore, the inner shell can rotate freely relative to the outer shell within the range of two-dimensional angular travel.

3. The rapid calibration method for non-contact two-dimensional angle measurement according to claim 2, characterized in that, In step 32, when the inertial measurement unit outputs angular rate information, the relationship between the Euler attitude angle and the recorded gyroscope rate output by the inertial measurement unit is as follows: Where φ1 represents the roll angle, θ1 represents the pitch angle, ψ1 represents the azimuth angle, p represents the output roll angular velocity, q represents the output pitch angular velocity, and r represents the output heading angular velocity.

4. The rapid calibration method for non-contact two-dimensional angle measurement according to claim 3, characterized in that, In step 32, when the inertial measurement unit outputs inertial attitude angle information, the relationship between the Euler attitude angle and the recorded gyroscope rate output by the inertial measurement unit is as follows: a1=cosθ0(0) a2=cosψ0(0) a3=cosφ0(0) a4=sinψ0(0) a5=sinθ0(0) a6=sinφ0(0) b1 = cosθ0(t) b2 = cosψ0(t) b3 = cosφ0(t) b4=sinψ0(t) b5 = sinθ0(t) b6 = sinφ0(t) C=B T *A φ0(0), θ0(0), and ψ0(0) represent the initial values ​​of roll angle φ0, pitch angle θ0, and azimuth angle ψ0 in the attitude angle data output by the inertial measurement unit in real time at the start of the calibration experiment, respectively; φ0(t), θ0(t), and ψ0(t) represent the sampled values ​​of roll angle φ0, pitch angle θ0, and azimuth angle ψ0 in the attitude angle data output by the inertial measurement unit in real time at time t after the start of the calibration experiment, respectively; C(i,j) represents the element in the i-th row and j-th column of matrix C; A is the transformation matrix between the inertial measurement unit's own coordinate system and the inertial coordinate system obtained based on the inertial measurement unit data at the start of the calibration experiment, and a1…a6 are the initial values ​​of the roll angle φ0, pitch angle θ0, and azimuth angle ψ0 in the attitude angle data output by the inertial measurement unit in real time at the start of the calibration experiment, respectively; C(i,j) represents the element in the i-th row and j-th column of matrix C; A is the transformation matrix between the inertial measurement unit's own coordinate system and the inertial coordinate system obtained based on the inertial measurement unit data at the start of the calibration experiment, respectively; a1…a6 are the initial values ​​of the roll angle φ0, pitch angle θ0, and azimuth angle ψ0 in the attitude angle data output by the inertial measurement unit in real time ... The coordinates of the pitch angle at the start of calibration are: cosine of the pitch angle at the start of calibration, cosine of the azimuth angle at the start of calibration, cosine of the roll angle at the start of calibration, sine of the azimuth angle at the start of calibration, and sine of the pitch angle at the start of calibration. B is the transformation matrix between the inertial measurement unit's own coordinate system and the inertial coordinate system obtained based on the data of the inertial measurement unit during the calibration test. b1...b6 are the coordinate transformation matrices of the pitch angle, azimuth angle, roll angle, azimuth angle, pitch angle, and roll angle during the calibration process, respectively. C is the coordinate transformation matrix of the inertial navigation system relative to the initial moment of calibration during the calibration process.

5. The rapid calibration method for non-contact two-dimensional angle measurement according to claim 4, characterized in that, In step 33, the roll angle φ1, pitch angle θ1, and azimuth angle ψ1 of the Euler attitude angles relative to the initial zero position are converted into the azimuth angle θ of the rotation around the initial zero position fixed point. a Pitch angle θ e Roll angle θ r : Where, θ a θ represents the azimuth angle of rotation about the initial zero position fixed point. e θ represents the pitch angle of rotation about the initial zero position. r θ represents the roll angle of rotation about the initial zero fixed point. iner k represents the absolute value of the angle vector representing rotation about the initial zero fixed point. xz For the sake of convenience in formula expression, x, y, and z are the x, y, and z coordinates of the unit vector of the angle vector of rotation relative to the initial zero fixed point.

6. The rapid calibration method for non-contact two-dimensional angle measurement according to claim 5, characterized in that, In step 34, under ideal installation conditions, the azimuth, pitch, and roll angles of the inner housing relative to the initial zero position and the corresponding angle measurement voltages have the following correspondence: In the formula, v 11 v 12 This represents the two readings of the first angle measurement, v 21 v 22 These represent the two readings of the second angle measurement.

7. The rapid calibration method for non-contact two-dimensional angle measurement according to claim 6, characterized in that, In step 34, considering the actual materialization error in the actual process, the relationship between the azimuth, pitch, and roll angles of the actual inner shell relative to the initial zero position and the corresponding angle measurement voltage is as follows: In the formula, α 11 α 12 α 21 α 22 To account for actual materialization errors, the inner shell rotates around the initial zero-position fixed point by an angle θ. a θ e θ r The linear combination of the linear error matrix between the two readings of the first angle measurement; β 11 β 12 β 21 β 22 To account for actual materialization errors, the rotation angle θ around the initial zero position fixed point is considered. a θ e θ r The linear error matrix between the linear combination of the two readings of the second angle measurement and the linear combination of the two readings; v 11_0 v 12_0 v 21_0 v 22_0 This indicates the offset error of the angle measurement reading introduced by the actual materialization error.

8. The rapid calibration method for non-contact two-dimensional angle measurement according to claim 7, characterized in that, In step 34, the relationship between the azimuth, pitch, and roll angles of the actual inner shell relative to the initial zero position and the corresponding angle measurement voltage is inverted and reversed: Based on the calculated θ a θ e θ r With the measured v 11 v 12 v 21 v 22 The value of A can be obtained through a fitting method. 11 A 12 A 21 A 22 θ 11_0 θ 12_0 B 11 B 12 B 21 B 22 θ 21_0 θ 22_0 ; A 11 A 12 A 21 A 22 The first two angle readings are used to measure the angle θ of the inner shell rotating around the initial zero point. a θ e θ r The elements of the linear error matrix between linear combinations, θ 11_0 and θ 12_0 This is the zero-position error in angle measurement caused by the bias error of the first angle measurement reading; Based on the same principle, calculate B. 11 B 12 B 21 B 22 The two readings of the second angle measurement are used to rotate the inner shell around the initial zero-position fixed point by the angle θ. a θ e θ r The elements of the linear error matrix between linear combinations; θ 21_0 and θ 22_0 This is the zero-position error in angle measurement caused by the bias error of the second angle measurement reading; The calibration results between the electrical signal of the angle measurement and the corresponding angle obtained in this embodiment are shown below: ζ1 represents the first weighting coefficient, and ζ2 represents the second weighting coefficient.

Images