Error compensation method for large-span laser horizontal ranging system

Abstract

The invention belongs to the technical field of plastic processing, and discloses an error compensation method for a large-span laser horizontal distance measurement system, which comprises the following steps: measuring a long-axis part, mounting a laser distance measurement sensor on the long-axis part, and enabling the laser distance measurement sensor to axially move on the long-axis part; the long-axis part is rotated to 0 degree in the axial direction, a reflector is installed on the laser distance measuring sensor, the laser light path of the laser distance measuring sensor is converted to be downward in gravity, a water tank is installed at the laser projection position, and liquid or a liquid film capable of reflecting laser is contained in the water tank; a laser distance measuring sensor is used for measuring the liquid or the liquid film; the method comprises the following steps: axially rotating a long-axis part to 90 degrees, taking down a reflecting mirror on a laser distance measuring sensor, carrying out gravity direction error measurement, measuring liquid or a liquid film, carrying out subtraction to obtain a system error delta a90n in the gravity direction when the long-axis part is 90 degrees, rotating a cross beam to 180 degrees, turning a light path of laser to be downward in gravity, and measuring the liquid or the liquid film, so as to obtain a system error delta a90n in the gravity direction when the long-axis part is 90 degrees. Calculating a downward system error delta a180n of the gravity when the difference of the long shaft part is 180 degrees; and finally, data processing is carried out to calculate errors of the ranging system. The straightness of the product is detected in a horizontal distance measuring mode, errors of measured data caused by bending deformation of a measured part and a measuring system due to self weight can be further reduced, assembly is simpler and more convenient, high-precision machining of the part is not needed, high-precision adjustment is not needed in the assembly process, the manufacturing cost of the measuring system is greatly reduced, and the manufacturing period of the measuring system is greatly shortened.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic processing, relates to a plastic processing method through extrusion deformation, and specifically relates to an error compensation method for a large-span laser horizontal ranging system. Background Art

[0002] The straightness measurement of shaft parts generally adopts the contact measurement method, that is, the two ends or other parts of the object to be measured are placed on the V-shaped iron, the probe of the micrometer is pressed on the object to be measured, the part is rotated along the axis, and the swing range of the pointer on the dial is read. After repeating the measurement of the micrometer at multiple positions, after comprehensive evaluation, its straightness can be obtained. The accuracy of this detection is affected by the density of the measuring points. It is difficult to accurately evaluate the true straightness of the measured object using traditional measurement technology, and it is impossible to achieve straightness measurement of non-rotating bodies. In recent years, with the rapid development of advanced measurement technology, laser ranging technology has been widely used in aerospace, metallurgical forging, geological exploration and other fields. Laser ranging can realize measurement tasks in harsh environments such as extreme temperature and extreme pressure, and it is easy to realize high-density, digital, and automated measurement tasks. It is one of the irreplaceable measurement technologies at present.

[0003] Since weak rigid shaft parts will bend and deform in the direction of gravity during the measurement process, and the measured parts will be disturbed when contact measurement is used, which can easily affect the measurement results. However, using laser horizontal distance measurement to measure the highest point on the side of such parts can eliminate the influence of the bending deformation of the parts themselves on the measurement accuracy. The use of non-contact measurement technology will not disturb the measured parts, and the measurement data can more accurately reflect the fluctuation of the outer surface of the measured parts. Rotating the measured parts along the axial direction can achieve three-dimensional measurement of the measured part surface, with more data samples and more reliable measurement results.

[0004] Especially when the measured part is a non-rotating body, the measured part can no longer be measured by traditional rotational measurement. The measurement process must be carried out along the axis direction. Traditional contact measurement cannot form a complete straightness measurement and must rely on three-coordinate measurement. The use of three-coordinate measurement is not only cumbersome in the measurement process and difficult to perform large-scale rapid measurement, but also three-coordinate measurement is charged by the number of measurement points, and the application cost is high.

[0005] At present, the main reason why it is difficult to achieve high-precision calibration of large-span laser horizontal ranging systems is mainly because the structural rigidity of the large-span system is reduced, the difficulty of assembling large-size components is increased, large-size standard measuring tools are difficult to process and use, and the technical difficulty of error compensation of the horizontal measurement system is much higher than that of the vertical system error compensation. The detailed explanation is as follows.

[0006] One is the impact of large-span ranging on structural rigidity. When the ranging span increases, in order to ensure that the linear guide rail carrying the laser ranging sensor has excellent straightness, the structural rigidity of the beam on which the linear rail is installed must be strengthened, or the beam must be processed with materials with better performance, or the cross-sectional dimensions of the beam must be increased, or the structure of the beam must be optimized. These methods will increase the material cost or processing cost of the beam.

[0007] The second is the impact of large-span ranging on the system assembly error. As the size of system components increases, the processing accuracy decreases, and the overall accuracy is difficult to adjust during the assembly process. This results in a decrease in the overall accuracy of the system. In order to maintain good measurement accuracy of the system, high-precision machine tools must be used for processing, or the accuracy must be downgraded, which affects the widespread application of laser horizontal ranging.

[0008] The third is the impact of large-span distance measurement on standard measuring tools. It is common and commonly used to make standard measuring tools with high hardness materials. Standard measuring tools have much higher straightness or flatness than the measurement system, and basically have no plasticity, and are not easy to deform after long-term storage. This type of standard measuring tool generally uses marble, high-hardness steel, etc. Their disadvantages are that large standard measuring tools have high manufacturing costs, heavy weight, are difficult to store and transport, and have a cumbersome calibration process.

[0009] Fourth, the impact of long-span ranging on the calibration direction. Since rigid standard measuring tools are not suitable for use in the calibration process of long-span ranging equipment, liquids or liquid films are also used as standard measuring tools. Liquids or liquid films are affected by gravity and their own fluidity, and their surfaces can remain horizontal for a long time, which can be considered as absolutely horizontal in engineering. Liquids or liquid films can be used to calibrate laser ranging in the gravity direction for low-cost long-span ranging. However, since the laser ranging calibration process requires the laser and the standard measuring tool to be approximately perpendicular, liquids or liquid films cannot directly meet the laser ranging calibration requirements in the horizontal direction. Summary of the invention

[0010] In order to solve the above problems, the present invention provides a large-span laser horizontal ranging system error compensation method. By optimizing the system error compensation algorithm, liquid or liquid film is used as a standard measuring tool for measurement, and the measurement data is processed, the compensation amount is included in the system, so as to realize high-efficiency, low-cost and high-precision horizontal straightness measurement of large-sized weak-rigidity shaft parts containing non-rotating parts.

[0011] The technical solution of the present invention is as follows:

[0012] A method for compensating a large-span laser horizontal ranging system error is provided for measuring a long-axis part, comprising the following steps:

[0013] S1, install the laser distance sensor on the long axis part, and the laser distance sensor can move axially on the long axis part;

[0014] S2, rotate the long axis part axially to 0°, install a reflector on the laser distance sensor, turn the laser optical path of the laser distance sensor to gravity downward, install a water tank at the laser projection position, and put a liquid or liquid film that can reflect the laser in the water tank; use the laser distance sensor to measure the liquid or liquid film to obtain (a 0n 、b 0n ), where a is the laser path length, b is the axial position of the laser distance sensor, subscript 0 represents 0°, and subscript n represents the nth point of the laser distance sensor on the long axis part with the measurement pitch as the interval;

[0015] S3, rotate the long axis part axially to 90°, remove the reflector on the laser ranging sensor, measure the gravity direction error, and obtain (a 90n 、b 90n ), the subscript 90 indicates 90°; a 90n Each number in the sequence is related to a 90n The minimum value a in the sequence 90nmin When the long axis of the part is 90°, b 90n System error Δa in the direction of gravity at 90n , that is, Δa 90n =a 90n -a 90nmin ;

[0016] S4, turn the beam to 180°, install the reflector on the laser distance sensor, turn the laser light path to gravity downward, and measure the horizontal reverse error; after measuring the liquid or liquid film, obtain (a 180n 、b 180n ), the subscript 180 means 180°; a 180n Each number in the sequence is related to a 180n The minimum value a in the sequence 180nmin When the cross beam is 180°, b 180n The systematic error of gravity downward at Δa 180n , that is, Δa 180n =a 180n -a 180nmin ;

[0017] S5, data processing, calculates the error of the ranging system.

[0018] Furthermore, the specific method of data processing in S5 includes:

[0019] When the beam is at 0°, b 0n Location,

[0020] h 0垂 =h 0垂装 +h 弯 =Δa 0n =a 0n -a 0nmin (1)

[0021] When the beam is at 90°, b 90n Location,

[0022] h 90水 =h 90水装 +h 弯 =Δa 90n =a 90n -a 90nmin (2)

[0023] When the beam is at 180°, b 180n Location,

[0024] h 180垂 =h 180垂装 +h 弯 =-h 0垂装 +h 弯 =Δa 180n =a 180n -a 180nmin (3)

[0025] Add equation (1) to equation (3),

[0026] h 0垂 +h 180垂 =(h 0垂装 +h 弯 )+(h 180垂装 +h 弯 )

[0027] Because h → 0垂装 =-h → 180垂装

[0028] So h 弯 =1 / 2(h 0垂 +h 180垂 )=1 / 2(Δa 0n +Δa 180n )(4)

[0029] Substituting formula (4) into formula (2),

[0030] h 90水装 =Δa 90n -h 弯 =Δa 90n -1 / 2(Δa 0n +Δa180n )

[0031] h represents error. The subscript "water" in h represents horizontal error, the subscript "vertical" in h represents vertical error, the subscript "bend" in h represents bending error, the subscript "water-installed" in h represents horizontal assembly error, and the subscript "vertical-installed" in h represents vertical assembly error. The superscript "arrow" in h represents a vector.

[0032] Laser distance sensor in b n The system compensation value of the horizontal distance measurement of the position is h 水装 =h 90水装 =Δa 90n -1 / 2(Δa 0n +Δa 180n ), and compensate the horizontal ranging system point by point according to the measurement pitch.

[0033] Furthermore, the laser ranging sensor is installed on the slider, the slider is installed on the linear guide, the slider is also installed on the adapter, the adapter is installed on the lead screw nut, the lead screw nut is installed on the lead screw parallel to the linear track, the lead screw is connected to the servo motor, and the position of the laser ranging sensor on the linear guide is controlled by controlling the servo motor to rotate left and right, and the linear guide is installed on the long axis part.

[0034] Further, both ends of the long axis part are installed in bearings, and the bearings are installed on the bed.

[0035] Furthermore, the method for obtaining the measurement pitch is as follows: the long-axis part is at the 0° position, the laser distance sensor emits a line laser in the horizontal direction, and a diffuse reflection is formed on the long-axis part as a bright line segment, the high point of the measured part is placed within the scanning range of the bright line segment, and the distance values ​​from the laser distance sensor to several points in the bright line segment are detected, and the minimum value of these distance values ​​is obtained, which is the measurement pitch; repeat this method to obtain (a n 、b n ) for all measured pitches.

[0036] Furthermore, the water tank is first left still to eliminate ripples on the reflective surface, and the water tank and the liquid or liquid film in the water tank no longer move during the entire measurement process.

[0037] Furthermore, unilateral measurement compensation is performed according to the system error: the long-axis part is turned to 0°, and the laser ranging sensor emits a line laser in the horizontal direction; the laser forms diffuse reflection on the long-axis part, and the appearance is a bright line segment; the high point of the measured part is placed within the scanning range of the bright line segment, and the distance values ​​of several points in the bright line segment from the laser ranging sensor are detected, so as to obtain the minimum value of these distance values, which is recorded as a1; at the same time, according to the number of revolutions of the servo motor, it is converted into the position b1 of the laser ranging sensor; the position of the laser ranging sensor on the long-axis part of the crossbeam is adjusted, and the above distance measurement action is repeated to obtain (a2, b2) to (a max 、bmax );(a max 、b max ) is the measured data, (a n +Δa 90n -1 / 2(Δ a0n +Δa 180n ), b n )Calculate the straightness of long axis parts.

[0038] Furthermore, a three-dimensional measurement compensation is performed according to the system error: the long-axis part is rotated by a certain angle, and step S5 is repeated to obtain the straightness of the long-axis part at multiple angles.

[0039] The beneficial effects of the present invention are as follows:

[0040] 1. The error compensation method of a large-span laser horizontal ranging system described in the present invention can further reduce the error of the measured data caused by the bending deformation of the measured parts and the measuring system due to their own weight by adopting a horizontal ranging method to detect the straightness of the product. The measuring principle is scientific and the measuring accuracy is higher, avoiding the cost increase caused by increasing the rigidity of the beam structure.

[0041] 2. The error compensation method for a large-span laser horizontal ranging system described in the present invention is easier to assemble, does not require high-precision processing of parts, and does not require high-precision adjustment during the assembly process, which greatly reduces the manufacturing cost and manufacturing cycle of the measurement system.

[0042] 3. The error compensation method for a large-span laser horizontal ranging system described in the present invention does not require a high-rigidity, integral standard measuring tool, but uses a low-cost liquid or liquid film surface as a standard measuring tool. The system itself is compensated through multi-angle measurement, which is conducive to forming an automated compensation program. It has low application cost, high measurement accuracy, is easy to use, and has strong reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solution of the implementation method of the patent of the present invention, the following is a brief introduction to the drawings required for use in the implementation method. It should be understood that the following drawings only show certain embodiments of the patent of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 It is a schematic side view of the horizontal compensation of the invented crossbeam at 0°;

[0045] Figure 2 It is a schematic side view of the vertical compensation of the invented crossbeam at 90°;

[0046] Figure 3It is a schematic side view of the reverse horizontal compensation of the invented crossbeam at 180°;

[0047] Figure 4 It is a side view schematic diagram of the invented laser level measurement principle;

[0048] 1. Laser distance sensor; 2. Adapter; 3. Slider; 4. Linear guide; 5. Screw nut; 6. Screw; 7. Beam; 8. Bearing; 9. Laser; 10. Water tank; 11. Liquid or liquid film; 12. Part to be measured; 13. Driving wheel; 14. Driven wheel; 15. Reflector. DETAILED DESCRIPTION

[0049] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0050] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships as given in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or case referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0051] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be interpreted in a broad sense, for example, it can be a fixed connection, a detachable connection or an integrated connection; it can be a mechanical connection or a point connection; it can be a direct connection or a connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0052] Embodiment 1:

[0053] A method for compensating a large-span laser horizontal ranging system error is provided for measuring a long-axis part, comprising the following steps:

[0054] S1, install the laser distance sensor on the long axis part, and the laser distance sensor can move axially on the long axis part;

[0055] S2, rotate the long axis part axially to 0°, install a reflector on the laser distance sensor, turn the laser optical path of the laser distance sensor to gravity downward, install a water tank at the laser projection position, and put a liquid or liquid film that can reflect the laser in the water tank; use the laser distance sensor to measure the liquid or liquid film to obtain (a 0n 、b 0n ), where a is the laser path length, b is the axial position of the laser distance sensor, subscript 0 represents 0°, and subscript n represents the nth point of the laser distance sensor on the long axis part with the measurement pitch as the interval;

[0056] S3, rotate the long axis part axially to 90°, remove the reflector on the laser ranging sensor, measure the gravity direction error, and obtain (a 90n 、b 90n ), the subscript 90 indicates 90°; a 90n Each number in the sequence is related to a 90n The minimum value a in the sequence 90nmin When the long axis of the part is 90°, b 90n System error Δa in the direction of gravity at 90n , that is, Δa 90n =a 90n -a 90nmin ;

[0057] S4, turn the beam to 180°, install the reflector on the laser distance sensor, turn the laser light path to gravity downward, and measure the horizontal reverse error; after measuring the liquid or liquid film, obtain (a 180n 、b 180n ), the subscript 180 means 180°; a 180n Each number in the sequence is related to a 180n The minimum value a in the sequence 180nmin When the cross beam is 180°, b 180n The systematic error of gravity downward at Δa 180n , that is, Δa 180n =a 180n -a 180nmin ;

[0058] S5, data processing, calculates the error of the ranging system.

[0059] The specific methods of data processing in S5 include:

[0060] When the beam is at 0°, b 0n Location,

[0061] h 0垂 =h 0垂装 +h弯 =Δa 0n =a 0n -a 0nmin (1)

[0062] When the beam is at 90°, b 90n Location,

[0063] h 90水 =h 90水装 +h 弯 =Δa 90n =a 90n -a 90nmin (2)

[0064] When the beam is at 180°, b 180n Location,

[0065] h 180垂 =h 180垂装 +h 弯 =-h 0垂装 +h 弯 =Δa 180n =a 180n -a 180nmin (3)

[0066] Using formula (1) plus formula (3),

[0067] h 0垂 +h 180垂 =(h 0垂装 +h 弯 )+(h 180垂装 +h 弯 )

[0068] Because h → 0垂装 =-h → 180垂装

[0069] So h 弯 =1 / 2(h 0垂 +h 180垂 )=1 / 2(Δa 0n +Δa 180n )(4)

[0070] Substitute formula (4) into formula (2):

[0071] h 90水装 =Δa 90n -h 弯 =Δa 90n -1 / 2(Δa 0n +Δa 180n )

[0072] h represents error. The subscript "water" in h represents horizontal error, the subscript "vertical" in h represents vertical error, the subscript "bend" in h represents bending error, the subscript "water-installed" in h represents horizontal assembly error, and the subscript "vertical-installed" in h represents vertical assembly error. The superscript "arrow" in h represents a vector.

[0073] Laser distance sensor in b n The system compensation value of the horizontal distance measurement of the position is h 水装 =h 90水装 =Δa 90n -1 / 2(Δa 0n +Δa 180n ), and compensate the horizontal ranging system point by point according to the measurement pitch.

[0074] The laser ranging sensor is installed on the slider, the slider is installed on the linear guide, the slider is also installed on the adapter, the adapter is installed on the lead screw nut, the lead screw nut is installed on the lead screw parallel to the linear track, the lead screw is connected to the servo motor, and the position of the laser ranging sensor on the linear guide is controlled by controlling the servo motor to rotate left and right. The linear guide is installed on the long axis part.

[0075] Both ends of the long shaft part are installed in bearings, and the bearings are installed on the bed.

[0076] The method for obtaining the measurement pitch is as follows: the long-axis part is at the 0° position, the laser distance sensor emits a line laser in the horizontal direction, and a diffuse reflection is formed on the long-axis part as a bright line segment. The high point of the measured part is placed within the scanning range of the bright line segment, and the distance values ​​from the laser distance sensor to several points in the bright line segment are detected. The minimum value of these distance values ​​is obtained, which is the measurement pitch; repeat this method to obtain (a n 、b n ) for all measured pitches.

[0077] The water tank is first left still to eliminate ripples on the reflective surface. During the entire measurement process, the water tank and the liquid or liquid film in the water tank no longer move.

[0078] Perform unilateral measurement compensation based on system error: turn the long-axis part to 0°, and the laser distance sensor emits a line laser in the horizontal direction; the laser forms diffuse reflection on the long-axis part, and the appearance is a bright line segment; place the high point of the measured part within the scanning range of the bright line segment, and detect the distance values ​​of several points in the bright line segment from the laser distance sensor, so as to obtain the minimum value of these distance values, recorded as a1; at the same time, according to the number of revolutions of the servo motor, convert it into the position b1 of the laser distance sensor; adjust the position of the laser distance sensor on the long-axis part of the crossbeam, and repeat the above distance measurement action to obtain (a2, b2) to (a max 、b max );(a max 、b max ) is the measured data, (an +Δa 90n -1 / 2(Δ a0n +Δa 180n ), b n )Calculate the straightness of long axis parts.

[0079] Perform stereo measurement compensation according to the system error: rotate the long-axis part by a certain angle, repeat step S5, and obtain the straightness of the long-axis part at multiple angles.

[0080] Embodiment 2:

[0081] A method for compensating errors in a large-span horizontal laser ranging system.

[0082] The laser distance sensor is installed on the slider, the slider is installed on the linear guide rail, the slider is also installed on the adapter, the adapter is installed on the lead screw nut, the lead screw nut is installed on the lead screw parallel to the linear track, the lead screw is connected to the servo motor, and the position of the laser distance sensor on the linear guide rail can be accurately controlled by controlling the left and right rotation of the servo motor and accurately controlling the position characteristics. The linear guide rail is installed on a rotatable beam, both ends of the beam are installed in bearings, and the bearings are installed on the bed. The beam can be rotated manually or driven by a motor, and the beam can be fixed at 0°, 90°, and 180° relative to the initial position.

[0083] The errors of the ranging system mainly include: the measurement error of the laser ranging sensor body, the mechanical assembly error of all components, the crossbeam bending error, etc. It should be noted that the error compensation range involved in the present invention does not include the measurement error of the laser ranging sensor body, and the horizontal ranging solution has eliminated the influence of the gravity direction on the measurement system, that is, the gravity direction component of the mechanical assembly error of all components and the crossbeam bending error. The system error referred to in the present invention only includes the horizontal direction component of the mechanical assembly error of the components.

[0084] By taking advantage of the influence of gravity and its own fluidity on liquid or liquid film, its surface can remain horizontal for a long time, which can be considered as absolutely horizontal in engineering. In addition, by taking advantage of the characteristics of reflectors such as internal reflection prisms or front surface coated reflectors, which can change the light path without causing light path decomposition, it is easy to convert horizontal laser into vertical laser and avoid interference with measurement data caused by light path decomposition. The beam is made of uniform metal and many components are assembled on the beam. By adjusting the counterweight, the center of gravity of each section of the measurement system is on the central axis of the beam rotation, that is, when the beam is at 0°, 90°, and 180°, the bending state of the beam itself is consistent.

[0085] Turn the beam to 0°, which is the working position. The laser distance sensor emits a line laser in the horizontal direction. The line laser forms a diffuse reflection on the measured part, and the appearance is a bright line segment. When measuring, place the high point of the measured part within the scanning range of the bright line segment, and the distance values ​​of several points in the line segment from the laser distance sensor can be detected, so as to obtain the minimum value of these distance values, which is recorded as a1. At the same time, according to the number of revolutions of the servo motor, it is converted into the position b1 of the laser distance sensor. Adjust the position of the laser distance sensor on the beam and repeat the above distance measurement action to obtain (a2, b2), ..., (a n , b n ). n , b n ) is the coordinate value, which can calculate or describe the straightness of the measured part. However, the straightness has not been compensated for errors at this time. If you want to accurately compensate the measured data, you need to complete the following work:

[0086] When measuring the horizontal compensation error of the measuring system at 0°, install a reflector on the laser distance sensor to turn the laser light path to the vertical direction. Install a water tank at the position of the online laser projection, and put a liquid or liquid film that can reflect the laser in the water tank so that the laser line segment is completely projected on the liquid or liquid film. Let it stand to eliminate the ripples on the reflective surface. The water tank should be large enough so that the water tank and the liquid or liquid film in the water tank will not move during the subsequent measurement process. After measuring the liquid or liquid film, the obtained (a 0n , b 0n ) is when the beam is at 0° and the laser ranging sensor is at b 0n When the laser path length a 0n . Use a 0n with a 0n The minimum value a in the sequence 0nmin By making a difference, we can obtain that the beam is at the 0° position, b 0n System error Δa in the direction of gravity at 0n , that is, Δa 0n =a 0n -a 0nmin n represents the installation distance of the laser ranging sensor along the axis of the beam, so a 0n With b 0n is a sequence of numbers with varying values ​​of n.

[0087] Turn the beam to 90°, which is the vertical error compensation position, remove the reflector on the laser distance sensor, and measure the gravity direction error of the measurement system. After measuring the liquid or liquid film, the obtained (a 90n , b 90n ) is when the laser ranging sensor is at b 90n When the laser path length a 90n . Use a90n with a 90n The minimum value a in the sequence 90nmin By making a difference, we can obtain that when the beam is 90°, b 90n System error Δa in the direction of gravity at 90n , that is, Δa 90n =a 90n -a 90nmin .

[0088] Turn the beam to 180°, which is the reverse horizontal error compensation position, install the reflector on the laser distance sensor, turn the laser light path to the gravity direction, and measure the reverse horizontal error of the measurement system. After measuring the liquid or liquid film, the obtained (a 180n , b 180n ) is when the laser ranging sensor is at b 180n When the laser path length a 180n . Use a 180n with a 180n The minimum value a in the sequence 180nmin By making a difference, we can obtain that when the beam is 180°, b 180n System error Δa in the direction of gravity at 180n , that is, Δa 180n =a 180n -a 180nmin .

[0089] Because the cosine function COS1°=0.999847, that is, when the laser is irradiated in the horizontal or vertical direction, the measured laser path is very close to the absolute horizontal and gravity direction. The horizontal and absolute horizontal, vertical and gravity direction referred to in the present invention have the same meaning in mathematical calculations. Assume that during the assembly process, the assembly gap of each moving element is 0, that is, there is no system clearance when the beam is at 0°, 90°, and 180°. The error in the horizontal direction h 水 It is composed of the mechanical assembly error in the horizontal direction, while the error in the vertical direction h 垂 It is composed of the mechanical assembly error in the vertical direction and the beam bending error. Then h 水 =h 水装 ;h 垂 =h 垂装 +h 垂弯 The bending deformation of the beam at 0°, 90°, and 180° is the same, so h → 0垂弯 =-h → 180垂弯 ,h 弯 =h 垂弯 =h water bend.

[0090] When the beam is at 0°, b 0n Location,

[0091] h 0垂 =h 0垂装 +h 弯 =Δa 0n =a 0n -a 0nmin (1)

[0092] When the beam is at 90°, b 90n Location,

[0093] h 90水 =h 90水装 +h 9弯 =Δa 90n =a 90n -a 90nmin (2)

[0094] When the beam is at 180°, b 180n Location,

[0095] h 180垂 =h 180垂装 +h 弯 =-h 0垂装 +h 弯 =Δa 180n =a 180n -a 180nmin (3)

[0096] Using formula (1) plus formula (3),

[0097] h 0垂 +h 180垂 =(h 0垂装 +h 弯 )+(h 180垂装 +h 弯 )

[0098] Because h → 0垂装 =-h → 180垂装

[0099] So h 弯 =1 / 2(h 0垂 +h 180垂 )=1 / 2(Δa 0n +Δa 180n )(4)

[0100] Substitute formula (4) into formula (2):

[0101] h 90水装 =Δa 90n -h 弯 =Δa 90n -1 / 2(Δa 0n +Δa 180n)

[0102] Since the assembly error does not change with the change of the beam rotation angle, the laser distance sensor is n The system compensation value of the horizontal distance measurement of the position should be h 水装 =h 90水装 =Δa 90n -1 / 2(Δa 0n +Δa 180n ). The horizontal distance measurement system can be compensated point by point according to the measurement pitch.

[0103] The technical solution of the present invention is a method for compensating a large-span laser horizontal ranging system error, comprising the following specific steps:

[0104] 1. Turn the beam to 0° (axial rotation angle), install a reflector on the laser distance sensor, and turn the laser light path to the vertical direction. Install a water tank at the position of the online laser projection, and put a liquid or liquid film that can reflect the laser into the water tank, so that the laser line segment is completely projected on the liquid or liquid film, and let it stand to eliminate the ripples on the reflective surface. The water tank should be large enough so that the water tank and the liquid or liquid film in the water tank will not move during the subsequent measurement process. After measuring the liquid or liquid film, the (a 0n 、b 0n ) is when the beam is at 0° and the laser ranging sensor is at b 0n When the laser path length a 0n . Use a 0n with a 0n The minimum value a in the sequence 0nmin By making a difference, we can obtain that the beam is at the 0° position, b 0n System error Δa in the direction of gravity at 0n , that is, Δa 0n =a 0n -a 0nmin .

[0105] 2. Turn the beam to 90°, remove the reflector on the laser distance sensor, and measure the gravity direction error of the measurement system. After measuring the liquid or liquid film, the obtained (a 90n 、b 90n ) is when the laser ranging sensor is at b 90n When the laser path length a 90n . Use a 90n with a 90n The minimum value a in the sequence 90nmin By making a difference, we can obtain that when the beam is 90°, b 90n System error Δa in the direction of gravity at 90n , that is, Δa 90n =a 90n -a 90nmin.

[0106] 3. Turn the beam to 180°, install the reflector on the laser distance sensor, turn the laser light path to the direction of gravity, and measure the horizontal reverse error of the measurement system. After measuring the liquid or liquid film, the obtained (a 180n , b 180n ) is when the laser ranging sensor is at b 180n When the laser path length a 180n . Use a 180n with a 180n The minimum value a in the sequence 180nmin By making a difference, we can obtain that when the beam is 180°, b 180n System error Δa in the direction of gravity at 180n , that is, Δa 180n =a 180n -a 180nmin .

[0107] 4. Data processing. Error in the horizontal direction h 水 It is composed of the mechanical assembly error in the horizontal direction, while the error in the vertical direction h 垂 It is composed of the mechanical assembly error in the vertical direction and the beam bending error. Then h 水 =h 水装 ;h 垂 =h 垂装 +h 垂弯 The bending deformation of the beam at 0° and 180° is the same and in opposite directions, so h → 0垂弯 =-h → 180垂弯 .

[0108] When the beam is at 0°, b 0n Location,

[0109] h 0垂 =h 0垂装 +h 弯 =Δa 0n =a 0n -a 0nmin (1)

[0110] When the beam is at 90°, b 90n Location,

[0111] h 90水 =h 90水装 +h 弯 =Δa 90n =a 90n -a 90nmin (2)

[0112] When the beam is at 180°, b180n Location,

[0113] h 180垂 =h 180垂装 +h 弯 =-h 0垂装 +h 弯 =Δa 180n =a 180n -a 180nmin (3)

[0114] Using formula (1) plus formula (3),

[0115] h 0垂 +h 180垂 =(h 0垂装 +h 弯 )+(h 180垂装 +h 弯 )

[0116] Because h → 0垂装 =-h → 180垂装

[0117] So h 弯 =1 / 2(h 0垂 +h 180垂 )=1 / 2(Δa 0n +Δa 180n )(4)

[0118] Substitute formula (4) into formula (2):

[0119] h 90水装 =Δa 90n -h 弯 =Δa 90n -1 / 2(Δa 0n +Δa 180n )

[0120] Since the assembly error does not change with the change of the beam rotation angle, the laser distance sensor is n The system compensation value of the horizontal distance measurement of the position should be h 水装 =h 90水装 =Δa 90n -1 / 2(Δa 0n +Δa 180n ). The horizontal distance measurement system can be compensated point by point according to the measurement pitch.

[0121] Embodiment 3:

[0122] 1. System composition. The laser distance sensor 1 is mounted on the adapter 2, the adapter 2 is mounted on the slider 3, the slider 3 is mounted on the linear guide 4, and the adapter 2 is mounted on the lead screw nut 5, the lead screw nut 5 is mounted on the lead screw 6 parallel to the linear guide 4, the lead screw 6 is directly driven by the servo motor, and the position of the laser distance sensor 1 in the system is precisely controlled by controlling the servo motor to rotate left and right. The linear guide 4 is mounted on a rotatable beam 7, and both ends of the beam 7 are mounted in bearings 8. The beam 7 can rotate and can be fixed at positions of 0°, 90°, and 180° relative to the initial position.

[0123] 2. Turn the beam 7 to 0°, install a reflector 15 on the laser distance sensor 1, and turn the optical path of the laser 9 to the vertical direction. Install a water tank 10 at the laser projection position of the laser distance sensor 1, and put a liquid or liquid film 11 that can reflect the laser into the water tank 10, so that the laser 9 line segment is completely projected on the liquid or liquid film 11, and let it stand to eliminate the ripples on the reflective surface. The water tank 10 should be large enough, and the water tank 10 and the liquid or liquid film 11 in the water tank will not move during the subsequent measurement process. After measuring the liquid or liquid film 11, the obtained (a 0n 、b 0n ) is when the beam 7 is at the 0° position and the laser distance sensor 1 is at b 0n When the laser 9 path length a 0n . Use a 0n with a 0n The minimum value a in the sequence 0nmin By making a difference, we can obtain that the beam 7 is at the 0° position, b 0n System error Δa in the direction of gravity at 0n , that is, Δa 0n =a 0n -a 0nmin .

[0124] 3. Turn the beam 7 to 90°, remove the reflector 15 on the laser distance sensor 1, and measure the gravity direction error of the measurement system. After measuring the liquid or liquid film 11, the obtained (a 90n 、b 90n ) is when the laser distance sensor 1 is in b 90n When the laser path length a 90n . Use a 90n with a 90n The minimum value a in the sequence 90nmin By making a difference, we can obtain that when the cross beam 7 is 90°, b 90n System error Δa in the direction of gravity at 90n , that is, Δa 90n =a 90n -a 90nmin .

[0125] 4. Turn the beam 7 to 180°, install the reflector 15 on the laser distance sensor 1, turn the optical path of the laser 9 to the direction of gravity, and measure the horizontal reverse error of the measurement system. After measuring the liquid or liquid film 11, the obtained (a 180n , b 180n ) is when the laser distance sensor 1 is in b 180n When the laser 9 path length a 180n . Use a 180n with a 180n The minimum value a in the sequence 180nmin By making a difference, we can obtain that when the beam is 180°, b 180n System error Δa in the direction of gravity at 180n , that is, Δa 180n =a 180n -a 180nmin .

[0126] 5. Data processing. Horizontal error h 水 It is composed of the mechanical assembly error in the horizontal direction, while the error in the vertical direction h 垂 It is composed of the mechanical assembly error in the vertical direction and the bending error of the beam 7. Then h 水 =h 水装 ;h 垂 =h 垂装 +h 垂弯 The bending deformation of beam 7 at 0° and 180° is the same and in opposite directions, so h → 0垂弯 =-h → 180垂弯 .

[0127] When beam 7 is at 0°, b 0n Location,

[0128] h 0垂 =h 0垂装 +h 弯 =Δa 0n =a 0n -a 0nmin (1)

[0129] When beam 7 is at 90°, b 90n Location,

[0130] h 90水 =h 90水装 +h 弯 =Δa 90n =a 90n -a 90nmin (2)

[0131] When beam 7 is at 180°, b180n Location,

[0132] h 180垂 =h 180垂装 +h 弯 =-h 0垂装 +h 弯 =Δa 180n =a 180n -a 180nmin (3)

[0133] Using formula (1) plus formula (3),

[0134] h 0垂 +h 180垂 =(h 0垂装 +h 弯 )+(h 180垂装 +h 弯 )

[0135] Because h → 0垂装 =-h → 180垂装

[0136] So h 弯 =1 / 2(h 0垂 +h 180垂 )=1 / 2(Δa 0n +Δa 180n )(4)

[0137] Substitute formula (4) into formula (2):

[0138] h 90水装 =Δa 90n -h 弯 =Δa 90n -1 / 2(Δa 0n +Δa 180n )

[0139] Since the assembly error does not change due to the change of the rotation angle of the beam 7, the laser distance sensor 1 is n The system compensation value of the horizontal distance measurement of the position should be h 水装 =h 90 Water loading = Δa 90n -1 / 2(Δa 0n +Δa 180n ). According to the measurement pitch, the horizontal distance measurement system is compensated point by point, then a 0n +Δa 90n -1 / 2(Δa 0n +Δa 180n ) is the actual measured value, that is, n The measured value at should be a n+Δa 90n -1 / 2(Δ a0n +Δa 180n ).

[0140] 6. Single-sided measurement compensation. When using the system for laser level measurement, turn the crossbeam 7 to 0°, and the laser distance sensor 1 emits a line laser 9 in the horizontal direction. The laser 9 forms a diffuse reflection on the measured part 12, and its appearance is a bright line segment. During measurement, place the high point of the measured part 12 within the scanning range of the bright line segment, and the distance values ​​of several points in the line segment from the laser distance sensor 1 can be detected, so as to obtain the minimum value of these distance values, which is recorded as a1. At the same time, according to the number of revolutions of the servo motor, it is converted into the position b1 of the laser distance sensor 1. Adjust the position of the laser distance sensor 1 on the crossbeam 7, and repeat the above distance measurement action to obtain (a2, b2), ..., (a n 、b n ). (a n 、b n ) is the measured data. After compensation, (a n +Δa 90n -1 / 2(Δ a0n +Δa 180n ), b n ) can accurately calculate or describe the straightness of the measured part 12.

[0141] 7. Body measurement compensation. Under the action of the rotational force of the driving wheel 12 and the supporting force of the driven wheel 13, the measured part is rotated by a certain angle, and step 5 is repeated to obtain the straightness of the measured part 12 at multiple angles, and the overall straightness of the measured part 12 can be judged.

Claims

1. A method for compensating the error of a large-span laser horizontal ranging system for measuring long-axis parts, characterized in that: The following steps are involved: S1, install the laser distance sensor on the long axis part, and the laser distance sensor can move axially on the long axis part; S2, rotate the long axis part axially to 0°, install a reflector on the laser distance sensor, turn the laser optical path of the laser distance sensor to gravity downward, install a water tank at the laser projection position, and put a liquid or liquid film that can reflect the laser in the water tank; use the laser distance sensor to measure the liquid or liquid film to obtain (a 0n 、b 0n ), where a is the laser path length, b is the axial position of the laser distance sensor, subscript 0 represents 0°, and subscript n represents the nth point of the laser distance sensor on the long axis part with the measurement pitch as the interval; S3, rotate the long axis part axially to 90°, remove the reflector on the laser ranging sensor, measure the gravity direction error, and obtain (a 90n 、b 90n ), the subscript 90 indicates 90°; a 90n Each number in the sequence is related to a 90n The minimum value a in the sequence 90nmin When the long axis of the part is 90°, b 90n System error Δa in the direction of gravity at 90n , that is, Δa 90n =a 90n -a 90nmin ; S4, turn the beam to 180°, install the reflector on the laser distance sensor, turn the laser light path to gravity downward, and measure the horizontal reverse error; after measuring the liquid or liquid film, obtain (a 180n 、b 180n ), the subscript 180 means 180°; a 180n Each number in the sequence is related to a 180n The minimum value a in the sequence 180nmin When the cross beam is 180°, b 180n The systematic error of gravity downward at Δa 180n , that is, Δa 180n =a 180n -a 180nmin ; S5, data processing, calculates the error of the ranging system.

2. The error compensation method for a large-span laser horizontal ranging system according to claim 1, characterized in that: The specific methods of data processing in S5 include: When the beam is at 0°, b 0n Location, h 0垂 =h 0垂装 + h 弯 =Δa 0n =a 0n -a 0nmin (1) When the beam is at 90°, b 90n Location, h 90水 =h 90水装 + h 弯 =Δa 90n =a 90n -a 90nmin (2) When the beam is at 180°, b 180n Location, h 180垂 =h 180垂装 + h 弯 =-h 0垂装 + h 弯 =Δa 180n =a 180n -a 180nmin (3) Using formula (1) plus formula (3), h 0垂 +h 180垂 =(h 0垂装 +h 弯 )+(h 180垂装 +h 弯 ) Because h → 0垂装 =-h → 180垂装 So h 弯 = 1 / 2(h 0垂 + h 180垂 ) = 1 / 2(Δa 0n + Δa 180n )(4) Substitute formula (4) into formula (2): h 90水装 =Δa 90n -h 弯 =Δa 90n -1 / 2(Δa 0n +Δa 180n ) h represents error. The subscript "water" in h represents horizontal error, the subscript "vertical" in h represents vertical error, the subscript "bend" in h represents bending error, the subscript "water-installed" in h represents horizontal assembly error, and the subscript "vertical-installed" in h represents vertical assembly error. The superscript "arrow" in h represents a vector. Laser distance sensor in b n The system compensation value of the horizontal distance measurement of the position is h 水装 =h 90水装 =Δa 90n -1 / 2(Δa 0n +Δa 180n ), and compensate the horizontal ranging system point by point according to the measurement pitch.

3. The error compensation method for a large-span laser horizontal ranging system according to claim 1 is characterized in that: The laser ranging sensor is installed on the slider, the slider is installed on the linear guide, the slider is also installed on the adapter, the adapter is installed on the lead screw nut, the lead screw nut is installed on the lead screw parallel to the linear track, the lead screw is connected to the servo motor, and the position of the laser ranging sensor on the linear guide is controlled by controlling the servo motor to rotate left and right. The linear guide is installed on the long axis part.

4. The error compensation method for a large-span laser horizontal ranging system according to claim 1, characterized in that: Both ends of the long shaft part are installed in bearings, and the bearings are installed on the bed.

5. The error compensation method for a large-span laser horizontal ranging system according to claim 1, characterized in that: The method for obtaining the measurement pitch is as follows: the long-axis part is at the 0° position, the laser distance sensor emits a line laser in the horizontal direction, and a diffuse reflection is formed on the long-axis part as a bright line segment. The high point of the measured part is placed within the scanning range of the bright line segment, and the distance values ​​from the laser distance sensor to several points in the bright line segment are detected. The minimum value of these distance values ​​is obtained, which is the measurement pitch; repeat this method to obtain (a n , b n ) for all measured pitches.

6. The error compensation method for a large-span laser horizontal ranging system according to claim 1, characterized in that: The water tank is first left still to eliminate ripples on the reflective surface. During the entire measurement process, the water tank and the liquid or liquid film in the water tank no longer move.

7. The error compensation method for a large-span laser horizontal ranging system according to claim 1, characterized in that: Perform unilateral measurement compensation based on system error: turn the long-axis part to 0°, and the laser distance sensor emits a line laser in the horizontal direction; the laser forms diffuse reflection on the long-axis part, and the appearance is a bright line segment; place the high point of the measured part within the scanning range of the bright line segment, and detect the distance values ​​of several points in the bright line segment from the laser distance sensor, so as to obtain the minimum value of these distance values, recorded as a1; at the same time, according to the number of revolutions of the servo motor, convert it into the position b1 of the laser distance sensor; adjust the position of the laser distance sensor on the long-axis part of the crossbeam, and repeat the above distance measurement action to obtain (a2, b2) to (a max , b max );(a max , b max ) is the measured data, (a n +Δa 90n -1 / 2(Δ a0n +Δa 180n ), b n )Calculate the straightness of long axis parts.

8. The error compensation method for a large-span laser horizontal ranging system according to claim 7, characterized in that: Perform stereo measurement compensation according to the system error: rotate the long-axis part by a certain angle, repeat step S5, and obtain the straightness of the long-axis part at multiple angles.

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