Device and method for measuring swing angle of flexible spray pipe by adopting stay wire type sensor

Abstract

The invention discloses a flexible spray pipe swing angle measuring device and method adopting a stay wire type sensor, and belongs to the technical field of engine testing methods. By designing a measuring device comprising a fixed support, three groups of stay wire displacement sensors and a swing angle resolving system, during testing, the fixed support is sleeved on the periphery of the flexible spray pipe, and the three groups of stay wire displacement sensors are mounted on the fixed support, so that a stay wire of each group of displacement sensors is correspondingly connected with a hanging point of a nozzle of the spray pipe. Displacement data of three hanging points are collected through a stay wire displacement sensor, corresponding space coordinates of the hanging points are converted through a swing angle resolving system, the plane where the three hanging points are located at the current moment and the next moment can be obtained, and then the variable quantity of the swing angle between the two moments can be calculated through a swing angle calculation formula. And the swinging angle at any moment can be determined by comparing and calculating with the axis position of the flexible spray pipe at the initial moment. The method solves the problem that an existing measurement mode is insufficient in measurement precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine test methods, in particular to a flexible nozzle swing angle measuring device and method using a pull wire sensor. BACKGROUND

[0002] Flexible nozzle technology has gradually matured and is applied to aircraft attitude control. During the swing test process, the flexible nozzle swing center is deformed by the actuator pressure, and the nozzle is controlled to swing in three degrees of freedom (i.e., swinging around the x, y, and z axes, representing pitch, yaw, and roll). In the test, the nozzle swing angle is tested to verify whether the actuator can generate sufficient force / torque to push the nozzle to the designed swing angle under simulated real load conditions. Currently, flexible nozzle swing angle testing mainly includes angular displacement measurement and photoelectric measurement.

[0003] Angular displacement measurement is commonly performed using an angular displacement sensor. During ground testing, the swing angle is calculated by the tension and compression changes of the sensor at the connection between the expansion section and the equipment tooling. The displacement sensor is relatively less affected by environmental factors and is easy to operate. However, in the actual testing process, relying on the calculation method of the single-dimensional expansion length of the expansion section and the geometric relationship cannot overcome the measurement errors generated by each transmission link, and therefore the data reliability is poor.

[0004] Photoelectric measurement includes infrared laser displacement sensor measurement and binocular vision distance measurement. Infrared laser displacement sensor measurement continuously emits a laser beam from the laser sensor to the swing nozzle to obtain the displacement of the measurement point in real time. Binocular vision distance measurement generally consists of two or more CCD cameras and an image processing system. Through image transmission, the swing angle and the swing center position of the flexible nozzle can be calculated using a binocular vision algorithm. Photoelectric measurement is affected by objective factors such as light and site, and the measurement accuracy cannot be guaranteed.

[0005] Therefore, it is necessary to provide a flexible nozzle swing angle measuring device and method using a pull wire sensor to solve the above problems. SUMMARY

[0006] Technical problems to be solved: In order to avoid the shortcomings of the prior art, the present application provides a flexible nozzle swing angle measuring device and method using a pull wire sensor. Three groups of pull wire displacement sensors are used to measure the spatial positions of the three hanging points of the flexible nozzle mouth. In the three-degree-of-freedom dynamic process, the actuator is leveled, and the swing center position and swing angle of the flexible nozzle are output in real time. The measurement accuracy is reliable, thereby solving the problem of insufficient measurement accuracy of the existing measurement method.

[0007] The technical scheme of the present application is: a flexible nozzle swing angle measuring device using a pull wire sensor, comprising: a fixed support, three groups of pull wire displacement sensors, and a swing angle calculation system. The fixed support is sleeved outside the flexible nozzle in the swing test, the fixed support test platform is fixedly connected and perpendicular to the axis of the initial position of the flexible nozzle, the end of the fixed support facing the nozzle of the flexible nozzle is not higher than the nozzle end surface of the flexible nozzle, and the fixed support is used for mounting the wire displacement sensor; The three groups of wire displacement sensors are mounted on the fixed support, three hanging points are uniformly distributed around the nozzle of the flexible nozzle, one group of wire displacement sensors is connected to each hanging point, the three wire displacement sensors are a group, the wire displacement sensors in the same group are mounted on the fixed support adjacent to the corresponding hanging point and cannot be mounted on the same straight line, and the wire ends of the wire displacement sensors in the same group are connected to the corresponding hanging points. The swing angle calculation system is used for converting the data collected by the three groups of wire displacement sensors into the coordinates of the corresponding hanging points and calculating the real-time swing angle of the flexible nozzle according to the coordinate change amounts of the three hanging points.

[0008] A further technical scheme of the present application is that the fixed support is a stainless steel cubic frame structure, and the distance between the fixed support and the nozzle end surface of the flexible nozzle is 500mm-1500mm.

[0009] A further technical scheme of the present application is that the swing angle calculation system adopts hardware NI PXI combined with software LabVIEW.

[0010] A flexible nozzle swing angle measurement method using a wire type sensor, the method is performed by using the measurement device, and the method comprises the following steps: The fixed support is mounted outside the flexible nozzle, and the three groups of wire displacement sensors are mounted on the fixed support and connected to the corresponding hanging points. A space coordinate system O-xyz is established by using a laser tracker, the position of the nozzle end surface of the flexible nozzle at the initial moment, the position of the axis corresponding to the end surface and the positions of the wire sensors are obtained; The position change data of the hanging points during the test swing of the flexible nozzle are measured by the three groups of wire displacement sensors and are transmitted to the swing angle calculation system, and the swing angle calculation system converts the measurement data of the wire sensors into the real-time coordinates of the three hanging points. The coordinates of the three hanging points determine a plane at the n moment, and the coordinates of the three hanging points determine another plane at the n+1 moment. The dot product operation of the normal vectors of the two planes is performed, the inverse cosine function is used to obtain the included angle of the normal vectors, and the swing angle change amount of the flexible nozzle between the n moment and the n+1 moment is obtained. The absolute swing angle of the nozzle at any moment is obtained by taking the axis position corresponding to the nozzle end surface of the flexible nozzle at the initial moment as a reference and combining the swing angle change amounts at each moment.

[0011] A further technical solution of the present application is that the conversion formula for converting the measurement value of the pull wire displacement sensor into the hanging point coordinates is: D i1 =Sqr[(x i1 - x i ) 2 +(y i1 - y i ) 2 +(z i1 - z i ) 2 ] D i2 =Sqr[(x i2 - x i ) 2 +(y i2 - y i ) 2 +(z i2 - z i ) 2 ] D i3 =Sqr[(x i3 - x i ) 2 +(y i3 - y i ) 2 +(z i3 - z i ) 2 ] In the formula, i is a hanging point, i=1, 2, 3; D i1 is the first sensor measurement data corresponding to the i-th hanging point, D i2 is the second sensor measurement data corresponding to the i-th hanging point, D i3 is the third sensor measurement data corresponding to the i-th hanging point; (x i , y i , z i ) is the coordinate of the i-th hanging point, (x i1 , y i1 , z i1 ) is the first sensor coordinate corresponding to the i-th hanging point, (x i2 , y i2 , z i2 ) is the second sensor coordinate corresponding to the i-th hanging point, and (x i3 , y i3 , z i3 ) is the third sensor coordinate corresponding to the i-th hanging point.

[0012] A further technical solution of the present application is that the plane determined by the coordinates of the three hanging points at the n-th moment is: An x+B n y+C n z+D n =0 wherein A n =(y2-y1)×(z3-z1)-(y3-y1)×(z2-z1) B n =(z2-z1)×(x3-x1)-(z3-z1)×(x2-x1) C n =(x2-x1)×(y3-y1)-(x3-x1)×(y2-y1) D n =-A n x1-B n y1-C n z1 wherein A n , B n , C n , D n are parameters of the plane equation of the nozzle end face at the n time, (x1, y1, z1) is the coordinate of the first hanging point at the n time, (x2, y2, z2) is the coordinate of the second hanging point at the n time, and (x3, y3, z3) is the coordinate of the third hanging point at the n time; The plane determined by the coordinates of the three hanging points at the n+1 time is: A n+1 x+B n+1 y+C n+1 z+D n+1 =0 wherein A n+1 =(y'2-y'1)×(z'3-z'1)-(y'3-y'1)×(z'2-z'1) B n+1 =(z'2-z'1)×(x'3-x'1)-(z'3-z'1)×(x'2-x'1) C n+1 =(x'2-x'1)×(y'3-y'1)-(x'3-x'1)×(y'2-y'1) D n+1 =-A n x'1-B n y'1-C n z'1 wherein A n+1 , B n+1 , C n+1 , D n+1The parameter of the plane equation of the nozzle mouth end face at the n+1 moment, (x'1, y'1, z'1) is the first hanging point coordinate at the n moment, (x'2, y'2, z'2) is the second hanging point coordinate at the n moment, and (x'3, y'3, z'3) is the third hanging point coordinate at the n+1 moment.

[0013] A further technical solution of the present application is that the calculation formula of the swing angle change amount between the n moment and the n+1 moment is: △Φ=arccos[(A n A n+1 +B n B n+1 +C n C n+1 ) / [Sqr(A n 2 +B n 2 +C n 2 )·Sqr(A n+1 2 +B n+1 2 +C n+1 2 ] In the formula, △Φ is the swing angle change amount between the n moment and the n+1 moment.

[0014] The present application has the following beneficial effects: The flexible nozzle swing angle measuring device and method of the present application adopt a stay wire type sensor, a fixed support is designed, the fixed support is sleeved on the periphery of the flexible nozzle, the fixed support is in a fixed state, three groups of stay wire displacement sensors are installed on the fixed support, three hanging points are uniformly distributed on the nozzle port of the flexible nozzle, the end of the stay wire of each group of displacement sensors is connected to a hanging point on the edge of the nozzle port, during the swing test, the displacement data of the hanging points are collected by the three groups of stay wire displacement sensors, the corresponding spatial coordinates of the hanging points are calculated by a swing angle calculation system according to the displacement data collected by the sensors, based on the principle that three points determine a plane, the plane where the three hanging points are located at the current moment can be obtained, the plane where the three hanging points are located at the next moment can be obtained in the same way, according to the determined planes where the three hanging points are located at the two moments, the swing angle change amount between the two moments can be calculated through the swing angle calculation formula, and the swing angle at any moment can be determined by comparing and calculating the position of the flexible nozzle axis at the initial moment.

[0015] The present application is a very stable contact type measuring tool which is formed by a stainless steel cubic frame structure and a pull-wire type displacement sensor, and can quickly and independently calculate the changes of three angles of pitch, yaw and roll through the reasonable spatial layout of the pull-wire type sensor, and truly realizes the test of three degrees of freedom swing angle. The method can test the static swing angle and capture the rapid dynamic swing process, adopts the direct displacement measurement mode, is not dependent on the intermediate complex mechanical transmission, greatly reduces the transmission error, and thus realizes the high-precision measurement of the flexible nozzle swing angle.

[0016] The present application adopts a pull-wire type displacement sensor group to break through the limitations of poor measurement accuracy of the angular displacement sensor and complex environmental factors of the photoelectric type measurement, and can assist the actuator to level in the three degrees of freedom dynamic process, and output the flexible nozzle swing angle in real time, and is fast in response and accurate and reliable in measurement result. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0018] Figure 1 A flexible nozzle swing angle measurement device using a pull-wire type sensor is connected to a flexible nozzle. Figure 2 A three-station dynamic spatial position measurement model schematic diagram. Figure 3 A swing angle calculation method schematic diagram.

[0019] In the figure: 1. fixed support, 2. pull-wire displacement sensor, 3. flexible nozzle, 31. first hanging point, 32. second hanging point, 33. third hanging point; W11, W12, W13 are respectively the first group of three pull-wire displacement sensors, W21, W22, W23 are respectively the second group of three pull-wire displacement sensors, W31, W32, W33 are respectively the third group of three pull-wire displacement sensors; a. axis of the flexible nozzle. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0021] Example 1 This embodiment provides a flexible nozzle sway angle measuring device using a draw-wire sensor, such as... Figure 1 As shown, the device includes: a fixed bracket, three sets of wire displacement sensors, and a swing angle calculation system.

[0022] The fixed bracket 1 is a stainless steel cubic frame structure, which is fitted around the flexible nozzle 3 during the swing test. The fixed bracket 1 is fixedly connected to the test platform and maintains a certain distance from the flexible nozzle 3 to avoid affecting its swing. The axis of the fixed bracket 1 is perpendicular to the initial position of the flexible nozzle 3. The end of the fixed bracket 1 facing the nozzle 3 does not protrude above the nozzle end face of the flexible nozzle 3, and the distance between it and the nozzle end face is 500mm~1500mm. The fixed bracket 1 is used to install the wire displacement sensor 2.

[0023] Three sets of wire displacement sensors 2 are provided, all mounted on fixed brackets 1, with three wire displacement sensors 2 in each set. Three mounting points are evenly distributed around the nozzle of the flexible nozzle 3: the first mounting point, the second mounting point, and the third mounting point. Adjacent mounting points are spaced 120° apart, and each mounting point corresponds to a set of wire displacement sensors. The wire displacement sensors 2 in the same set are mounted on the fixed brackets 1 near their corresponding mounting points, and the three wire displacement sensors 2 in the same set cannot be mounted on the same straight line. The ends of the wires of the wire displacement sensors 2 in the same set are all connected to their corresponding mounting points. Figure 1 As shown, the first group of three wire displacement sensors W11, W12, and W13 are all connected to hanging point I 31; the second group of three wire displacement sensors W21, W22, and W23 are all connected to hanging point II 32; and the third group of three wire displacement sensors W31, W32, and W33 are all connected to hanging point III 33. In this embodiment, the hanging point is an aluminum alloy rod target seat located on the outside of the large-diameter nozzle of the flexible nozzle 3. The rod target seat is used to fix the wire of the wire displacement sensor 2. The wire sensor 2 is installed at different positions of the fixing bracket 1 near the three hanging points using a base with adjustable direction. The three wire sensors in the same group cannot be installed on the same straight line, forming a spatial triangular pyramid structure with the hanging point. The angle between the axis of the wire sensor and the axis of the nozzle is between 30 degrees and 60 degrees.

[0024] The swing angle calculation system converts the data collected by three sets of wire displacement sensors into the coordinates of the corresponding anchor points, and calculates the real-time swing angle of the flexible nozzle based on the changes in the coordinates of the three anchor points. In this embodiment, the swing angle calculation system adopts the PXI modular hardware platform from National Instruments (NI) and uses LabVIEW graphical programming software to realize data acquisition and calculation processing.

[0025] Example 2 The embodiment provides a flexible nozzle swing angle measurement method using a stay wire type sensor. Step 1. Device installation. In the swing test of the flexible nozzle 2, the fixed support 1 is installed outside the flexible nozzle, so that the flexible nozzle 2 is centered on the fixed support 1. Three groups of stay wire displacement sensors 2 are installed on the fixed support 1, and the stay wire displacement sensors 2 are connected with corresponding hanging points at the nozzle of the flexible nozzle 2.

[0026] Step 2. Establishing a spatial coordinate system. A spatial coordinate system O-xyz is established by using a laser tracker, and the positions of the 3 nozzle end faces of the flexible nozzle at the initial moment, the positions of the axis a corresponding to the end faces in the spatial coordinate system and the positions of the stay wire sensors 2 in the spatial coordinate system are obtained.

[0027] Step 3. Calculating the swing angle change amount of the flexible nozzle between two moments.

[0028] The position change data of the corresponding hanging points of the flexible nozzle 3 during swing are measured by the three groups of stay wire displacement sensors 2, and are transmitted to a swing angle calculation system. The swing angle calculation system converts the measurement data of the stay wire sensors into real-time coordinates of the three hanging points. At the moment n, the three hanging point coordinates determine a plane, and at the moment n+1, the three hanging point coordinates determine another plane. The dot product of the normal vectors of the two planes is calculated, and the inverse cosine function is used to obtain the included angle of the normal vectors, that is, the swing angle change amount of the flexible nozzle between the moment n and the moment n+1 is obtained.

[0029] Specifically, the length change data of the stay wire measured by the stay wire displacement sensor 2 is converted into the spatial coordinates of the hanging points by the swing angle calculation system. The conversion formula is: D i1 =Sqr[(x i1 - x i ) 2 +(y i1 - y i ) 2 +(z i1 - z i ) 2 ] D i2 =Sqr[(x i2 - x i ) 2 +(y i2 - y i ) 2 +(z i2 - z i ) 2 ] D i3=Sqr[(x i3 - x i ) 2 +(y i3 - y i ) 2 +(z i3 - z i ) 2 ] In the formula, i represents the hanging point, i=1,2,3, that is, when i=1 it is the first hanging point, when i=2 it is the second hanging point, when i=3 it is the third hanging point, and point D... i1 D represents the measurement data of the first sensor corresponding to the i-th hanging point. i2 D represents the measurement data of the second sensor corresponding to the i-th hanging point. i3 For the third sensor measurement data corresponding to the i-th hanging point, each group contains three measurement data points, such as... Figure 1 As shown, the first group (D) 11 D 12 D 13 Group 2 (D) 21 D 22 Group D23), Group 2 (D 31 D 32 D 33 ). (x) i ,y i ,z i Let (x) be the coordinates of the i-th hanging point. i1 ,y i1 ,z i1 Let (x) be the coordinates of the first sensor corresponding to the i-th hanging point. i2 ,y i2 ,z i2 (x) represents the coordinates of the second sensor corresponding to the i-th hanging point. i3 ,y i3 ,z i3 ) represents the coordinates of the third sensor corresponding to the i-th hanging point.

[0030] Based on the principle that a plane can be determined by three points in space, the plane determined by the coordinates of the three points at time n is: A. n x+B n y+C n z+D n =0, which means the plane where the nozzle end face of the flexible nozzle is located at time n.

[0031] Among them, A n =(y2-y1)×(z3-z1)-(y3-y1)×(z2-z1) B n =(z2-z1)×(x3-x1)-(z3-z1)×(x2-x1) C n = (x2-x1) x (y3-y1) - (x3-x1) x (y2-y1) D n = -A n x1-B n y1-C n z1 wherein A n , B n , C n , D n are parameters of the plane equation of the nozzle end face at the n time, (x1, y1, z1) is the coordinate of the first hanging point at the n time, (x2, y2, z2) is the coordinate of the second hanging point at the n time, and (x3, y3, z3) is the coordinate of the third hanging point at the n time.

[0032] Similarly, the plane determined by the coordinates of the three hanging points at the next n+1 time is: A n+1 x+B n+1 y+C n+1 z+D n+1 = 0, that is, the plane in which the nozzle end face of the flexible nozzle at the n+1 time is located.

[0033] wherein A n+1 = (y'2-y'1) x (z'3-z'1) - (y'3-y'1) x (z'2-z'1) B n+1 = (z'2-z'1) x (x'3-x'1) - (z'3-z'1) x (x'2-x'1) C n+1 = (x'2-x'1) x (y'3-y'1) - (x'3-x'1) x (y'2-y'1) D n+1 = -A n x'1-B n y'1-C n z'1 wherein A n+1 , B n+1 , C n+1 , D n+1 are parameters of the plane equation of the nozzle end face at the n+1 time, (x'1, y'1, z'1) is the coordinate of the first hanging point at the n time, (x'2, y'2, z'2) is the coordinate of the second hanging point at the n time, and (x'3, y'3, z'3) is the coordinate of the third hanging point at the n+1 time.

[0034] As Figure 3 shown, according to the planes determined at two times, the swing angle change between the two times is calculated, and the calculation formula of the swing angle change amount between the n time and the n+1 time is: ΔΦ = arccos[(A n A n+1 +B n B n+1 +C n C n+1 ) / [Sqr(A n 2 +B n 2 +C n 2 )·Sqr(A n+1 2 +B n+1 2 +C n+1 2 ] In the formula, ΔΦ is the change of the swing angle between the n time and the n+1 time.

[0035] Step 4. Taking the axis position corresponding to the nozzle end face of the flexible nozzle at the initial time as the reference, the absolute swing angle of the nozzle at any time is obtained by accumulating the swing angle change at each time, that is, the swing angle Φ of the flexible nozzle 3 at any time is obtained.

[0036] The present application can determine the coordinates of the three hanging points through the 9-way sensor combined with the swing angle calculation system, and a plane can be determined through the three points not in a line in the space, and the coordinates of the three hanging points at the next time and the plane determined thereby can be obtained. The change of the swing angle between the two times is calculated by using the swing angle calculation formula. As shown in the formula, the swing angle Φ at any time can be determined by comparing and calculating with the axis position at the initial time, and the high-precision and rapid measurement of the swing angle of the flexible nozzle is realized. Figure 3

[0037] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.​

Claims

1. A flexible nozzle sway angle measuring device employing a draw-wire sensor, characterized in that, include: Fixed bracket, three sets of wire displacement sensors and pendulum angle calculation system; among which: The fixed bracket is fitted over the flexible nozzle in the swing test. The fixed bracket is fixedly connected to the test platform and is perpendicular to the axis of the initial position of the flexible nozzle. The end of the fixed bracket facing the nozzle of the flexible nozzle does not exceed the nozzle end face of the flexible nozzle. The fixed bracket is used to install the wire displacement sensor. All three sets of wire displacement sensors are mounted on fixed brackets; three hanging points are evenly distributed around the nozzle of the flexible nozzle, and each hanging point corresponds to a set of wire displacement sensors; the three wire displacement sensors form a set, and the wire displacement sensors of the same set are mounted on the fixed bracket of the corresponding hanging point, and cannot be mounted on the same straight line. The ends of the wires of the same set of wire displacement sensors are all connected to the corresponding hanging points. The swing angle calculation system is used to convert the data collected by the three sets of wire displacement sensors into the coordinates of the corresponding hanging points, and calculate the real-time swing angle of the flexible nozzle based on the changes in the coordinates of the three hanging points.

2. The measuring device according to claim 1, characterized in that, The fixed bracket is a stainless steel cubic frame structure, and the distance between it and the nozzle end face of the flexible nozzle is 500mm~1500mm.

3. The measuring device according to claim 1, characterized in that, The swing angle calculation system uses hardware NI PXI combined with software LabVIEW.

4. A method for measuring the swing angle of a flexible nozzle using a draw-wire sensor, characterized in that, The method uses the measuring device described in any one of claims 1 to 3 to perform the measurement, and the method includes the following steps: Install the fixed bracket on the outside of the flexible nozzle, install three sets of wire displacement sensors on the fixed bracket, and connect them to the corresponding hanging points; A spatial coordinate system O-xyz is established using a laser tracker to obtain the initial position of the nozzle end face, the corresponding axis position, and the positions of each wire sensor of the flexible nozzle. Three sets of wire displacement sensors are used to measure the position change data of the hanging points during the swing test of the flexible nozzle, and the data is transmitted to the swing angle calculation system. The swing angle calculation system converts the measurement data of the wire sensors into the real-time coordinates of the three hanging points. At time n, the coordinates of the three hanging points determine one plane; at time n+1, the coordinates of the three hanging points determine another plane. By multiplying the plane normal vectors at two time points, the angle between the normal vectors is obtained using the inverse cosine function, thus obtaining the change in the swing angle of the flexible nozzle between time n and time n+1. Using the axial position corresponding to the nozzle end face of the flexible nozzle at the initial moment as a reference, and combining the change in swing angle at each moment, the absolute swing angle of the nozzle at any moment is obtained by summing them up.

5. The method according to claim 4, characterized in that, The conversion formula for converting the measured values ​​of the wire displacement sensor into the coordinates of the hanging point is as follows: D i1 =Sqr[(x i1 - x i ) 2 +(y i1 - y i ) 2 +(z i1 − z i ) 2 ] D i2 =Sqr[(x i2 - x i ) 2 +(y i2 - y i ) 2 +(z i2 − z i ) 2 ] D i3 =Sqr[(x i3 - x i ) 2 +(y i3 - y i ) 2 +(z i3 − z i ) 2 ] In the formula, i is the hanging point, i=1,2,3; D i1 For the first sensor measurement data corresponding to the i-th attachment point, D i2 For the measurement data of the second sensor corresponding to the i-th hanging point, D i3 The measurement data of the third sensor corresponding to the i-th attachment point; (x i ,y i ,z i Let (x) be the coordinates of the hanging point i, and (x) be the coordinates of the hanging point i. i1 ,y i1 ,z i1 Let (x) be the coordinates of the first sensor corresponding to the i-th attachment point. i2 ,y i2 ,z i2 (x) represents the coordinates of the second sensor corresponding to the i-th attachment point. i3 ,y i3 ,z i3 ) represents the coordinates of the third sensor corresponding to the i-th hanging point.

6. The method according to claim 4, characterized in that, The plane determined by the coordinates of the three hanging points at time n is: A n x+B n y+C n z+D n =0 Among them, A n =(y2-y1)×(z3-z1)-(y3-y1)×(z2-z1) B n =(z2-z1)×(x3-x1)-(z3-z1)×(x2-x1) C n =(x2-x1)×(y3-y1)-(x3-x1)×(y2-y1) D n =-A n x1-B n y1-C n z1 In the formula, A n B n C n D n Let (x1, y1, z1) be the parameters of the plane equation of the nozzle end face at time n, (x2, y2, z2) be the coordinates of the first hanging point at time n, (x3, y3, z3) be the coordinates of the second hanging point at time n, and (x3, y3, z3) be the coordinates of the third hanging point at time n. The plane determined by the coordinates of the three hanging points at time n+1 is: A n+1 x+B n+1 y+C n+1 z+D n+1 =0 Among them, A n+1 =(y'2 - y'1)×(z'3 - z'1)-(y'3 - y'1)×(z'2 - z'1) B n+1 =(z'2-z'1)×(x'3-x'1)-(z'3-z'1)×(x'2-x'1) C n+1 =(x'2-x'1)×(y'3-y'1)-(x'3-x'1)×(y'2-y '1 ) D n+1 =-A n x'1-B n y'1-C n z'1 In the formula, A n+1 B n+1 C n+1 D n+1 Let (x'1, y'1, z'1) be the parameters of the plane equation of the nozzle end face at time n+1, (x'2, y'2, z'2) be the coordinates of the first hanging point at time n, (x'3, y'3, z'3) be the coordinates of the second hanging point at time n+1, and (x'3, y'3, z'3) be the coordinates of the third hanging point at time n+1.

7. The method according to claim 6, characterized in that, The formula for calculating the change in the pendulum angle between time n and time n+1 is: △Φ=arccos[(A n A n+1 +B n B n+1 +C n C n+1 ) / [Sqr(A n 2 +B n 2 +C n 2 )·Sqr(A n+1 2 +B n+1 2 +C n+1 2 )] In the formula, △Φ is the change in the pendulum angle between time n and time n+1.

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