CN115655121A - Non-contact length measuring system and method - Google Patents
Non-contact length measuring system and method Download PDFInfo
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- CN115655121A CN115655121A CN202211308321.9A CN202211308321A CN115655121A CN 115655121 A CN115655121 A CN 115655121A CN 202211308321 A CN202211308321 A CN 202211308321A CN 115655121 A CN115655121 A CN 115655121A
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Abstract
The invention belongs to the technical field of measuring instruments, and discloses a non-contact length measuring system and a non-contact length measuring method, wherein the main structure of the system comprises a laser, a beam splitting unit, an angle adjusting unit, a distance measuring module and a processing module; the laser is used for emitting point laser; the beam splitting unit is used for splitting a beam into two beams; the angle adjusting unit is used for adjusting the deflection angles of the two beams of light, so that the tail end of one beam of light is superposed with the bottom end point of the object to be measured, and the length direction of the light is perpendicular to the length direction of the object to be measured and is used as a reference light beam; the tail end of the other beam of light is superposed with the top end of the object to be tested and used as a test beam; calculating the length L of the object to be measured according to the included angle alpha between the reference light beam and the test light beam and the distance D between the system and the object to be measured; the system has the advantages of simple structure, simple computational logic, convenient operation, low cost and wide application prospect.
Description
The technical field is as follows:
the invention belongs to the technical field of measuring instruments, relates to laser measurement, and particularly relates to a non-contact length measuring system and method.
The background art comprises the following steps:
the laser measurement is widely applied to the fields of construction, exploration, industry, scientific research, biomedicine and the like, and non-contact measuring instruments on the market are common such as laser distance measuring machines, laser protractors and the like.
There are also studies on contactless measurements at present. For example, chinese patent application CN201821052376.7 discloses a dual-beam laser measuring instrument, which structurally comprises a first laser measuring instrument and a second laser measuring instrument, wherein the first laser measuring instrument and the second laser measuring instrument are connected up and down by a rotating connecting shaft, the first laser measuring instrument comprises a lower shell, a lower laser projection window is arranged in front of the lower shell, a first laser emitting head is arranged behind the lower laser projection window, a power supply board is arranged at the bottom of the lower shell, the second laser measuring instrument comprises an upper shell, an upper laser projection window is arranged in front of the upper shell, a second laser emitting head is arranged behind the upper laser projection window, a main control board is arranged inside the upper shell, the first laser emitting head and the second laser emitting head are respectively and electrically connected with the power supply board and the main control board, and the main control board is used for collecting emission feedback signals of the first laser emitting head and the second laser emitting head and collecting angle feedback numerical signals of relative rotation angles between the first laser measuring instrument and the second laser measuring instrument, and calculating angle numerical values according to the emission feedback signals; the device can measure the distance between two points at a long distance at a fixed point, and solves the problem that direct measurement cannot be carried out due to geographical condition limitation. However, in the prior art, the measurement depends on two laser instruments, the equipment structure is complex, and a measurement system capable of remotely measuring the distance between two points by only one laser instrument needs to be developed.
The invention content is as follows:
the invention aims to overcome the defects of the prior art and provides a non-contact length measuring system and a non-contact length measuring method,
in order to achieve the above object, the present invention provides a non-contact length measuring system, the main structure of which comprises a laser, a beam splitting unit, an angle adjusting unit, a distance measuring module, a processing module, a display module and an electronic sensor; the laser is used for emitting point laser; the beam splitting unit is positioned on the light emitting side of the laser and is used for splitting a beam into two beams; the angle adjusting unit is positioned on the light-emitting side of the beam splitting unit and comprises 2 adjusting units which are respectively used for adjusting the deflection angles of the two beams of light split by the beam splitting unit, so that the tail end of one beam of light is superposed with the bottom end point of the object to be measured, and the light is perpendicular to the length direction of the object to be measured and serves as a reference light beam; the tail end of the other beam of light is superposed with the top end of the object to be tested and used as a test beam; the electronic sensor is used for measuring an included angle theta 1 between an adjusting unit for adjusting the test light beam and the optical axis of the laser and an incident angle i1 of the light beam incident to an incident surface of the adjusting unit, so that an emergent angle i2 of the test light beam is obtained, and an included angle alpha between the reference light beam and the test light beam is obtained; the distance measuring module is positioned right below the laser and used for measuring the distance D between the system and the object to be measured; the processing module is used for calculating the length L of the object to be measured according to the included angle alpha and the distance D, and the display module is connected with the processing module through a line and used for displaying the included angle alpha, the distance D and the length L information of the object to be measured.
When the test object is far enough and the precision requirement is low, L = D × tan (α); when the test precision requirement is high, L = D × tan (α) + h + (D1 + D2)/2, where h is the center-to-center distance of the 2 adjusting units, and D1 and D2 are the spot sizes of the test beam and the reference beam at the position of the object to be measured, respectively.
The electronic sensor is used for measuring an included angle theta 1 between an adjusting unit for adjusting the test light beam and an optical axis of the laser and an incident angle i1 of the light beam incident to an incident surface of the adjusting unit, so that an emergent angle i2 of the test light beam is obtained, and an included angle alpha between the reference light beam and the test light beam is obtained, and the principle is as follows: if the incident angle of the light beam incident on the adjusting unit is i1, the included angle between the light incident surface and the light emergent surface of the adjusting unit is m, the refractive index of the adjusting unit is n2, the refractive index of air is n1, and the light beam emergent angle is i2, i2= arcsin { n } is obtained when i2= arcsin 2 *sin[arcsin(n 1 *sini 1 /n 2 )+m]N1}; setting the included angle between the light beam emergent surface and the optical axis of the laser to be theta 2, and keeping theta 1 consistent with theta 2 through structural design or assembly debugging; the angle alpha between the test beam and the reference beam is the angle alpha 2 between the test beam and the optical axis, and alpha = alpha 2= |90 ° -theta 1-i2|.
The beam splitting unit is an obtuse triangular prism, the section of the obtuse triangular prism is an obtuse triangle, and the obtuse angle of the obtuse triangular prism faces to the incident direction of the light beam.
The 2 adjusting units are deflection prisms, and each deflection prism corresponds to one beam of light; the deflection prism is an acute angle rhomboid or wedge-angle sheet element, namely, the included angle between the light incident surface and the light emergent surface is an acute angle, and the deflection of the incident light is realized through the acute angle.
And a collimation unit is arranged between the beam splitting unit and the laser and is used for focusing or collimating laser emitted by the laser into parallel light.
Compared with the prior art, the invention can obtain the length size of the object to be measured by dividing a beam emitted by one laser into two laser beams, aligning one of the laser beams with the bottom end of the object to be measured, enabling the light path to be vertical to the object to be measured, aligning the other laser beam with the other end of the object to be measured, and reading the included angle between the two laser beams and the distance between the measuring system and the object to be measured. Furthermore, the electronic sensing and laser ranging module is integrated on an electronic display screen, so that the measurement result is displayed timely, and convenience and intuition are realized; the system has the advantages of simple structure, simple computational logic, convenient operation, low cost and wide application prospect.
Description of the drawings:
fig. 1 is a schematic diagram of the overall structure of a non-contact length measuring system according to the present invention.
Fig. 2 is a schematic diagram of the working principle of the non-contact length measuring system according to the present invention.
Fig. 3 is a schematic view of the length measurement principle of the non-contact length measurement system according to the present invention.
The specific implementation mode is as follows:
the invention is further illustrated by the following examples in conjunction with the accompanying drawings.
Example 1:
the embodiment relates to a non-contact length measuring system, the main structure of which comprises a laser 1, a beam splitting unit 2, an angle adjusting unit 3, a distance measuring module 4, a processing module 5, a display module 6 and an electronic sensor 7; the laser 1 is used for emitting point laser; the beam splitting unit 2 is located on the light emitting side of the laser 1, and is configured to split one beam of light into two beams of light: a first light beam and a second light beam; angle adjusting unit3 is located at the light emitting side of the beam splitting unit 2, and the angle adjusting unit 3 includes an upper adjusting unit 31 and a lower adjusting unit 32 vertically arranged up and down, and respectively used for adjusting the deflection angles of the two beams of light split by the beam splitting unit 2; adjusting the lower adjusting unit 32 to make the tail end of the first light beam coincide with the bottom end point of the object to be measured, and the light beam is perpendicular to the length direction of the object to be measured and serves as a reference light beam; adjusting the upper adjusting unit 31 to make the tail end of the second light beam coincide with the top end of the object to be tested as a test light beam; the electronic sensor 7 is configured to measure an included angle θ 1 between the upper adjusting unit 31 and the optical axis of the laser 1 and an incident angle i1 of the light beam incident on the incident surface of the upper adjusting unit 31, so as to obtain an exit angle i2 of the test light beam, and derive an included angle α = |90 ° - θ 1-i2| (here, an absolute value) between the two light beams; the distance measuring module 4 is positioned right below the laser 1 or at other positions and is used for measuring the distance D between the system and an object to be measured; the distance measuring module 4 is located such that the center of the distance measuring module and the center of the angle adjusting unit are relatively constant, and an error β in the existing measuring distance can be calibrated through simple operation, for example, an object to be measured, the distance of which is easy to measure, is set, the vertical distance between the system and the object to be measured is H1 through the laser distance measuring module 4, the distance between the center of the angle adjusting unit 3 and the object to be measured is measured as D1, and then the constant error β = H1-D1 between the distance measuring module 4 and the angle adjusting unit 3, when the object to be measured with unknown distance is measured, the distance D = H- β between the system and the object to be measured is calculated, wherein H is the actual measured distance value of the distance measuring module, and β may be a negative number; the processing module 5 is used for calculating the length L of the object to be measured according to the included angle alpha and the distance D; when the test object is far enough and the accuracy requirement is low, L = D × tan (α); when the requirement of the test accuracy is high, L = D × tan (α) + h + (D1 + D2)/2, where h is the size of the center distance between the upper adjusting unit 31 and the lower adjusting unit 32, where D1 and D2 are the spot sizes of the test beam and the reference beam at the position of the object to be measured, respectively, and the sizes of D1 and D2 at different positions can be calculated by using a collimated laser beam propagation formula, such as D1= (4 λ M) = 2 f/Πφ)+(kD 3 /f 2 ) Where λ is the wavelength of the laser, M 2 Is the quality factor of the laser beam and,f is the effective focal length of the collimating lens, phi is the diameter of the light spot incident on the lens, and k is the diffraction coefficient of the lens, but the light spot can be obtained by directly and practically testing the light spot size at different distances due to the existence of lens processing errors and light beam quality errors; the display module 6 is in line connection with the processing module 5 and is used for displaying information such as an included angle alpha, a distance d, the length L of the object to be measured and the like.
The beam splitting unit 2 is an obtuse triangular prism, the section of the obtuse triangular prism is preferably an isosceles obtuse triangle (the advantages of symmetrical light paths and simple element structure), the double light paths can be realized by the approximate isosceles obtuse angle or the obviously asymmetrical obtuse triangle, and the obtuse angle faces to the incident direction of the light beam; a collimating unit 8 is disposed between the beam splitting unit 2 and the laser 1, and the collimating unit 8 is used for focusing or collimating the laser light emitted by the laser 1 into parallel light.
The upper adjusting unit 31 and the lower adjusting unit 32 are both deflection prisms, and each deflection prism corresponds to a beam of light; the deflection prism is an acute angle rhomboid prism or a wedge-angle sheet element, namely, the included angle between the light incident surface and the light emergent surface is an acute angle, and the deflection of the incident light is realized through the acute angle.
The laser is a laser diode (LD for short) or a laser diode pumped solid laser, the wavelength of the laser is more preferably CCD sensitive wavelength such as 405nm, 808nm, 980nm and the like, but the wavelength, the power and the packaging form do not influence the realization of the function of the patent, the wavelength of the laser is 300nm TO 2500nm, the power is 0.5mW TO 10W and the like, and the packaging form is TO packaging, F packaging or C packaging and the like.
The collimating unit is made of K9 glass, quartz, glass or plastic, preferably K9 glass, is cheap, has enough strength and low expansion coefficient, and can meet the industrial application requirement of the product.
The collimating unit is an aspheric plano-convex lens, or a combined lens of a plurality of spherical lenses, or an aspheric biconvex lens, or a spherical lens, or a cemented lens, and can achieve the effect of focusing or collimating the laser emitted by the LD; when the collimating unit is an aspheric plane-convex lens, the focusing effect is good, the collimating unit has certain spherical aberration eliminating capacity, and the collimating unit is cheap, small in number and simple in structure.
The distance between the collimation unit and the LD is determined by the focal length of the lens; the size of the focal length of the lens determines the size of the light spot at the exit of the light beam and the size of the divergence angle of the light beam after being adjusted to the collimated point laser.
The obtuse angle of the obtuse triangular prism is larger than 90 degrees, the obtuse angle is larger, the included angle of the two beams of split light is smaller, and similarly, the included angle of the two beams of split light is closer to 90 degrees, and the included angle of the two beams of split light is larger.
The acute angle used by the deflection prism is less than 90 degrees, the closer the acute angle is to 90 degrees, the larger the deflection amplitude of the light beam is, and the smaller the acute angle is, the smaller the deflection amplitude of the light beam is.
The deflection prism is an acute angle rhomboid prism or a circular wedge sheet or an acute angle prism lens in other shapes.
The non-contact length measuring system also comprises a power supply module and a support module, wherein the power supply module is used for supplying power to the whole system; the supporting module is used for fixing the system and keeping the measuring system from moving relatively in all operation processes, so that the precision and the effectiveness of the measuring process are ensured; furthermore, the supporting module can also provide tripod support, so that a lifting function and a pitch angle adjusting function are provided for the height of the measuring system, and the measurement of the size is more convenient.
The use method of the non-contact length measuring system in the embodiment comprises the following steps: firstly, a laser 1 of a measuring system is perpendicular to an object to be measured to emit a beam of point laser, and then a beam of light is split into two beams of light through a beam splitting unit 2; then, a lower adjusting unit 32 in the angle adjusting unit 3 is adjusted to enable the tail end of one beam of light (beam 1) to coincide with the bottom end of the object to be detected, and the light of the beam of light 1 is perpendicular or approximately perpendicular to the length direction of the object to be detected (when the light is completely perpendicular, the error is minimum, and a relatively rough precision result can be obtained by approximately perpendicular), at the moment, the beam of light 1 is parallel to the optical axis of the laser and is called as a reference beam; then, the upper adjusting unit 31 in the angle adjusting unit 3 is adjusted to make the other beam (beam 2) coincide with the top end of the object to be tested, and at the moment, the beam 2 and the optical axis of the laser have a certain included angle, which is called a test beam; at this time, the electronic sensor7 by measuring the angle θ 1 between the upper adjusting unit 31 and the optical axis of the laser, the angle α between the two light beams is derived (principle: if the incident angle of the light beam incident on the upper adjusting unit (deflection prism) is i1, the acute angle (the angle between the light incident surface and the light emergent surface) of the deflection prism is m, the refractive index of the deflection prism is n2, the refractive index of air is n1, and the light emergent angle is i2, i2= arcsin { n } is obtained 2 *sin[arcsin(n 1 *sini 1 /n 2 )+m]N1}; setting the included angle between the light beam emergent surface of the deflection prism and the optical axis of the laser to be theta 2, and keeping theta 1 consistent with theta 2 through structural design or assembly debugging; the angle α between the test beam and the reference beam is the angle α 2 between the test beam and the optical axis, and α = α 2= |90 ° - θ 1-i2| (absolute here)); the distance measurement module 4 is opened, the distance measurement module 4 adopts laser distance measurement, the position of a visible red light laser point vertically hitting on the object to be measured is adjusted until the visible red light laser point coincides with the position of the light beam 1, the distance D between the system and the object to be measured is measured, and the distance D is uploaded to the processing module 5; the processing module 5 calculates the length L of the object to be measured according to the included angle α and the distance D, when the object to be measured is far enough and the requirement for precision is low, L = D × tan (α), when the requirement for precision is high, L = D × tan (α) + h + (D1 + D2)/2, where h is the central distance between the angle adjusting units of the two deflection prisms, where D1 and D2 are the spot sizes of the test beam and the reference beam at the position of the object to be measured, respectively, and the sizes of D1 and D2 at different positions can be calculated by a collimated laser beam propagation formula, such as D1= (4 λ M) = (4 λ M) = 2 f/Πφ)+(kD 3 /f 2 ) Where λ is the wavelength of the laser, M 2 The laser beam quality factor is f, the effective focal length of the collimating lens is used, phi is the diameter of a light spot incident on the lens, and k is the diffraction coefficient of the lens, but due to the existence of lens processing errors and light beam quality errors, the laser beam quality factor can also be obtained by directly and actually testing the size of the light spot at different distances; the included angle alpha, the distance d and the length L of the object to be measured are all displayed on the display module 6.
Claims (6)
1. A non-contact length measuring system is characterized in that a main body structure comprises a laser, a beam splitting unit, an angle adjusting unit, a distance measuring module, a processing module, a display module and an electronic sensor; the laser is used for emitting point laser; the beam splitting unit is positioned on the light emitting side of the laser and is used for splitting a beam into two beams; the angle adjusting unit is positioned on the light-emitting side of the beam splitting unit and comprises 2 adjusting units which are respectively used for adjusting the deflection angles of the two beams of light split by the beam splitting unit, so that the tail end of one beam of light is superposed with the bottom end point of the object to be measured, and the light is perpendicular to the length direction of the object to be measured and serves as a reference light beam; the tail end of the other beam of light is superposed with the top end of the object to be tested and used as a test beam; the electronic sensor is used for measuring an included angle theta 1 between an adjusting unit for adjusting the test light beam and the optical axis of the laser and an incident angle i1 of the light beam incident to an incident surface of the adjusting unit, so that an emergent angle i2 of the test light beam is obtained, and an included angle alpha between the reference light beam and the test light beam is obtained; the distance measuring module is positioned right below the laser and used for measuring the distance D between the system and the object to be measured; the processing module is used for calculating the length L of the object to be measured according to the included angle alpha and the distance D, and the display module is connected with the processing module through a line and used for displaying the information of the included angle alpha, the distance D and the length L of the object to be measured.
2. The non-contact length measuring system of claim 1, wherein when the test object is far enough and the accuracy requirement is low, L = D x tan (α); when the test precision requirement is high, L = D × tan (α) + h + (D1 + D2)/2, where h is the center-to-center distance of the 2 adjusting units, and D1 and D2 are the spot sizes of the test beam and the reference beam at the position of the object to be measured, respectively.
3. The system of claim 1, wherein the electronic sensor is configured to measure an angle θ 1 between an adjusting unit for adjusting the test beam and an optical axis of the laser and an incident angle i1 of the beam incident on an incident surface of the adjusting unit, so as to obtain an angle of departure i2 of the test beam, and thus an angle α between the reference beam and the test beam, according to the following principle: let the incident angle of the light beam incident on the adjusting unit be i1, and the adjusting unitThe included angle between the light incidence surface and the light emergence surface of the element is m, the refractive index of the adjusting unit is n2, the refractive index of air is n1, the light beam emergence angle is i2, and then i2= arcsin { n } n 2 *sin[arcsin(n 1 *sini 1 /n 2 )+m]N1}; setting the included angle between the light beam emergent surface and the optical axis of the laser to be theta 2, and keeping theta 1 consistent with theta 2 through structural design or assembly debugging; the angle alpha between the test beam and the reference beam is the angle alpha 2 between the test beam and the optical axis, and alpha = alpha 2= |90 ° -theta 1-i2|.
4. The system according to claim 1, wherein the beam splitting unit is an obtuse triangular prism having a cross section of an obtuse triangle with an obtuse angle facing the incident direction of the light beam.
5. The system of claim 1, wherein the 2 adjustment units are deflection prisms, each corresponding to a beam of light; the deflection prism is an acute angle rhomboid or wedge element, i.e. the included angle between the light incident surface and the light emergent surface is an acute angle, and the deflection of the incident light is realized through the acute angle.
6. The system according to claim 1, wherein a collimating unit is disposed between the beam splitting unit and the laser, and the collimating unit is configured to focus or collimate the laser light emitted from the laser into parallel light.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211308321.9A CN115655121A (en) | 2022-10-25 | 2022-10-25 | Non-contact length measuring system and method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211308321.9A CN115655121A (en) | 2022-10-25 | 2022-10-25 | Non-contact length measuring system and method |
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| CN115655121A true CN115655121A (en) | 2023-01-31 |
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| CN202211308321.9A Pending CN115655121A (en) | 2022-10-25 | 2022-10-25 | Non-contact length measuring system and method |
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