Laser displacement sensor measuring device and method suitable for metal surface anti-interference

Abstract

The invention discloses an anti-interference laser displacement sensor measuring device and method suitable for a metal surface. Firstly, a solid angle model of a laser beam emitted by a laser diode of the laser displacement sensor is established, and total solid angle information of the laser beam diffused by a diffusion lens is calculated; then establishing a light path model when the laser displacement sensor is independently used, and calculating solid angle information of a light receiving element of the sensor; establishing a light path model when the laser displacement sensors are combined for use, and calculating solid angle information of adjacent light receiving elements of the sensors; and finally, calculating threshold constraint conditions when the laser displacement sensors are used independently and in combination, establishing a neutral optical filter parameter constraint model by using the constraint conditions, and placing a proper neutral optical filter at the front part of the receiving end of the sensor. According to the invention, the problem that the laser displacement sensor has no response or has abnormal response when facing a metal surface can be solved, and meanwhile, the method has certain anti-interference capability in a scene in which multiple sensors are simultaneously applied.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric measurement, and in particular relates to a laser displacement sensor measurement device and method suitable for metal surface anti-interference. Background Art

[0002] Laser displacement sensors are widely used in manufacturing, robotics, construction engineering and other fields to measure and monitor the displacement, vibration, shape and other parameters of objects. The application targets of laser displacement sensors are mainly diffuse reflection surfaces. When the target to be measured is a metal surface, due to the mirror reflection of the reflective surface, the light receiving element cannot stably receive the signal, so the sensor often has no response or abnormal response.

[0003] In the manufacturing industry, laser displacement sensors often need to measure metal surfaces. Since mirror reflection mainly occurs on metal surfaces, traditional technologies will have no response or abnormal response when facing mirror reflection surfaces, which limits the promotion and application scope of laser displacement sensors. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a laser displacement sensor measurement device and method suitable for anti-interference on metal surfaces. First, a solid angle model of the light beam emitted by the laser diode of the laser displacement sensor is established, and the total solid angle information of the laser beam after being diffused by the diffusion lens is calculated; then, an optical path model when the laser displacement sensor is used alone is established, and the solid angle information of the sensor's own light-receiving element is calculated; next, an optical path model when the laser displacement sensor is used in combination is established, and the solid angle information of the sensor's neighboring light-receiving element is calculated; finally, the threshold constraint conditions when the laser displacement sensor is used alone and in combination are calculated, and the constraint conditions are used to establish a neutral filter parameter constraint model, and the filter transmittance parameters are calculated using the model, and a suitable neutral filter is placed in front of the sensor receiving end. The present invention can solve the problem of no response or abnormal response of the laser displacement sensor when facing a metal surface, and at the same time has a certain anti-interference ability in the scenario where multiple sensors are used simultaneously.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0006] A laser displacement sensor measuring device suitable for metal surface anti-interference, comprising a housing, a guide rail, a diffusion lens, a neutral filter and a lens slot;

[0007] The guide rail is installed in the housing;

[0008] The diffusion lens is placed in the housing, facing the side of the housing, and is mounted on the inner guide rail of the housing through the lens slot;

[0009] The neutral density filter and the diffusion lens are placed in parallel and installed in front of the receiving end of the laser displacement sensor;

[0010] The guide rail is composed of two vertical rods and a horizontal rod. The horizontal rod and the vertical rod are fixed by screws, and the position of the horizontal rod is adjusted according to screw holes with different lengths.

[0011] A laser displacement sensor measurement method suitable for metal surface anti-interference includes the following steps:

[0012] Step 1: Install the housing according to the size of the laser displacement sensor, fix the diffusion lens through the lens slot, adjust the position of the lens slot to ensure that the geometric center of the diffusion lens coincides with the geometric center of the sensor laser diode, and fix it in the screw hole of the guide rail with screws; install the neutral filter to the front of the sensor receiving end so that the filter can completely cover the sensor receiving end;

[0013] Step 2: Establish a solid angle model of the light beam emitted by the laser diode of the laser displacement sensor, and calculate the total solid angle information of the laser beam after it is diffused by the diffusion lens;

[0014] Step 3: Establish an optical path model when the laser displacement sensor is used alone, and calculate the solid angle information of the sensor's own light-receiving element;

[0015] Step 4: Establish an optical path model when the laser displacement sensor is used in combination, and calculate the solid angle information of the light receiving element of the sensor's adjacent machine;

[0016] Step 5: Calculate the threshold constraints of the laser displacement sensors when used alone and in combination, use the constraints to establish a neutral filter parameter constraint model, then use the model to calculate the transmittance parameters of the filter, and finally place the neutral filter in front of the sensor receiving end.

[0017] Furthermore, the step 2 is specifically as follows:

[0018] The angle of the beam emitted by the laser diode after passing through the diffusion lens is:

[0019]

[0020] Where r0 represents the radius of the circular laser beam emitted by the laser diode, and f0 represents the focal length of the diffusion lens;

[0021] The differential solid angle of the emitted beam is:

[0022]

[0023] Where Ω represents the total solid angle of the emitted laser beam,

[0024] The total solid angle of the emitted beam is expressed as:

[0025]

[0026] Furthermore, the step 3 is specifically as follows:

[0027] From the geometric relationship, we can know that:

[0028]

[0029]

[0030] Where θ1 represents the angle between the focus of the diffusion lens and the two vertices in the front view of the virtual image of the light-receiving element, θ2 represents the angle between the vertical line from the focus of the diffusion lens to the reflecting surface and the left vertex in the front view of the virtual image of the light-receiving element, d represents the measuring distance, L2 represents the horizontal distance from the focus of the diffusion lens to the light-receiving element, and L3 represents the length of the light-receiving element;

[0031] The angle between the focal point of the diffusion lens and the two vertices of the virtual image of the light receiving element is:

[0032]

[0033] Where W0 represents the width of the sensor's light-receiving element;

[0034] The solid angle of the light beam received by the light receiving element of this machine is expressed as:

[0035]

[0036] The energy received by the light-receiving element of this machine is expressed as:

[0037]

[0038] Furthermore, the step 4 is specifically as follows:

[0039] Assuming that two laser displacement sensors are installed in parallel, the horizontal distance between the geometric center of the laser diode of the left sensor and the light-receiving element of the adjacent sensor is:

[0040] L2′=L1+2L2+L3+L4+L d

[0041] Where L1 represents the distance between the center of the laser diode and the left shell, L2 represents the distance between the center of the laser diode and the light receiving element, L3 represents the length of the light receiving element, L4 represents the distance between the light receiving element and the right shell, and L d Indicates the spacing between sensors;

[0042] From the geometric relationship, we know that:

[0043]

[0044]

[0045]

[0046] Where θ1′ represents the angle between the focus of the diffusion lens and the vertices on both sides of the virtual image of the adjacent light receiving element, and θ2′ represents the angle between the vertical line from the focus of the diffusion lens to the reflection surface and the vertex on the left side of the virtual image of the adjacent light receiving element; The angle between the focal point of the sensor diffusion lens and the two vertices on the left side of the adjacent light-receiving element. W0 represents the width of the sensor light-receiving element.

[0047] The solid angle of the light beam received by the adjacent light receiving element is expressed as:

[0048]

[0049] The energy received by the neighboring light receiving element is expressed as:

[0050]

[0051] Furthermore, the step 5 is specifically as follows:

[0052] When a neutral filter is installed at the receiving end of the laser displacement sensor, in order to prevent the laser displacement sensor from being interfered by neighboring machines when used in combination, the energy of the light beam received by the sensor's light-receiving element through the filter should be greater than the threshold value T0, that is:

[0053] ηEN1>T0

[0054] The energy of the light beam emitted by the neighboring machine received by the sensor light receiving element through the filter should be less than the threshold value T0, that is:

[0055] ηEN2<T0

[0056] Combining the above two equations, we get:

[0057]

[0058] Will and Substituting into the above formula, the constraint model of the transmittance parameter of the neutral density filter is obtained as follows:

[0059]

[0060] Input sensor intrinsic parameters r0, W0, L1, L2, L3, L4, L5, L2′, T0, EN, diffusion lens focal length f0, measurement distance d and spacing L between adjacent sensors d , the neutral filter parameter constraint model is used to select a filter that meets the transmittance parameters of the model, and finally the neutral filter is installed in front of the receiving end of the laser displacement sensor.

[0061] The beneficial effects of the present invention are as follows:

[0062] The present invention provides a laser displacement sensor measurement method and device suitable for anti-interference on metal surfaces, which can solve the problem of no response or abnormal response of the laser displacement sensor when facing a metal surface. At the same time, it has a certain anti-interference ability in the scenario where multiple sensors are used simultaneously, thereby broadening the application scope of the laser displacement sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 This is a schematic diagram of a sensor external attachment device according to an embodiment of the present invention;

[0064] Figure 2 Schematic diagram of the solid angle information of the light beam emitted by the laser displacement sensor according to an embodiment of the present invention, wherein (a) is the optical path diagram of the sensor transmitting end, and (b) is the solid angle model of the light beam emitted by the sensor;

[0065] Figure 3 Schematic diagram of the solid angle information of the light receiving element of the machine according to an embodiment of the present invention, wherein (a) is a working optical path diagram of the sensor, and (b) is a solid angle model of the light receiving element;

[0066] Figure 4 Schematic diagram of the solid angle information of the light receiving element of the neighboring machine according to an embodiment of the present invention, wherein (a) is the working optical path diagram of the sensor, and (b) is the solid angle model of the light receiving element;

[0067] Figure 5 Schematic diagram of a method for calculating filter parameters according to an embodiment of the present invention.

[0068] In the figure: 1 guide rail, 2 lens slot, 3 diffusion lens, 4 neutral density filter, 5 housing, 6 laser displacement sensor. DETAILED DESCRIPTION

[0069] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0070] The object of the present invention is to provide a laser displacement sensor measuring device and method suitable for metal surface anti-interference, so as to solve the problem of no response or abnormal response in the prior art when the measured target is a metal surface.

[0071] The present invention adopts the following technical solutions:

[0072] A laser displacement sensor measuring device suitable for metal surface anti-interference comprises a shell, and a guide rail, a diffusion lens, a neutral filter and a lens slot installed in the shell.

[0073] The diffusion lens is placed in the housing, facing the side of the housing, and is installed on the internal guide rail of the housing through the lens slot. The neutral density filter and the diffusion lens are placed in parallel and installed in front of the sensor receiving end. The guide rail consists of two vertical rods and a horizontal rod. The horizontal rod and the vertical rod are fixed by screws, and the position of the horizontal rod can be adjusted according to the screw holes of different lengths.

[0074] A laser displacement sensor measurement method suitable for metal surface anti-interference, used for a laser displacement sensor external device, also includes the following steps:

[0075] S1. Install a suitable external housing according to the size of the laser displacement sensor, fix the diffusion lens through the lens slot, adjust the lens slot to a suitable position, ensure that the geometric center of the diffusion lens coincides with the geometric center of the sensor laser diode, and fix it in the screw hole of the guide rail with screws, and install the neutral filter to the front of the sensor receiving end so that the filter can completely cover the sensor receiving end;

[0076] S2. Establish a solid angle model of the light beam emitted by the laser diode of the laser displacement sensor, and calculate the total solid angle information of the laser beam after it is diffused by the diffusion lens;

[0077] S3, establish the optical path model when the laser displacement sensor is used alone, and calculate the solid angle information of the sensor's own light receiving element;

[0078] S4, establish an optical path model when the laser displacement sensor is used in combination, and calculate the solid angle information of the light receiving element of the sensor adjacent machine;

[0079] S5. Calculate the threshold constraints of laser displacement sensors when used alone and in combination, use the constraints to establish a neutral filter parameter constraint model, use the model to calculate the transmittance parameters of the filter, and finally place a suitable neutral filter in front of the sensor receiving end.

[0080] Example:

[0081] like Figure 1 As shown, a laser displacement sensor measurement method and device suitable for anti-interference of metal surfaces include a housing and a guide rail, a diffusion lens, a neutral filter and a lens slot installed in the housing. The diffusion lens is placed in the housing on the side facing the housing and is installed on the guide rail through the lens slot. The neutral filter is placed parallel to the diffusion lens and installed to the front of the sensor receiving end. The guide rail consists of two vertical rods and a horizontal rod. The horizontal rod and the vertical rod are fixed by screws, and the position of the horizontal rod can be adjusted according to the screw holes of different lengths.

[0082] Before using the laser displacement sensor and external devices for detection, adjust the lens slot to a suitable position according to the size of the sensor, ensure that the diffusion lens is located in front of the sensor transmitting end, and the geometric center of the diffusion lens coincides with the geometric center of the sensor laser diode, and the neutral filter is located in front of the sensor receiving end.

[0083] (1) Establish a solid angle model of the light beam emitted by the laser displacement sensor

[0084] like Figure 2 As shown in (a), the angle of the beam emitted by the laser diode after passing through the diffusion lens is:

[0085]

[0086] Where r0 is the radius of the circular laser beam emitted by the laser diode, f0 is the focal length of the diffusion lens, and Ω is the total solid angle of the emitted laser beam.

[0087] like Figure 2 As shown in (b), the differential solid angle of the emitted light beam is:

[0088]

[0089] The total solid angle of the emitted beam can be expressed as:

[0090]

[0091] (2) Calculate the solid angle information of the light receiving element of the sensor when it is used alone

[0092] like Figure 3 As shown, from the geometric relationship, we can know that:

[0093]

[0094]

[0095] Wherein θ1 represents the angle between the focus of the diffusion lens and the two vertices in the front view of the virtual image of the light-receiving element, θ2 represents the angle between the perpendicular line from the focus of the diffusion lens to the reflecting surface and the left vertex in the front view of the virtual image of the light-receiving element, f0 represents the focal length of the diffusion lens, d represents the measuring distance, L2 represents the horizontal distance from the focus of the diffusion lens to the light-receiving element, and L3 represents the length of the light-receiving element.

[0096] like Figure 3 As shown in (b), the angle between the focal point of the diffusion lens and the two vertices of the virtual image of the light receiving element is:

[0097]

[0098] Where W0 represents the width of the sensor's light-receiving element.

[0099] The solid angle of the light beam received by the original light receiving element of this machine can be expressed as:

[0100]

[0101] The energy received by the original light receiving element of this machine can be expressed as:

[0102]

[0103] (3) Calculation of the solid angle information of the adjacent light receiving element when the sensors are used in combination

[0104] like Figure 4 As shown in (a), assuming that two laser displacement sensors are installed in parallel, the horizontal distance between the geometric center of the laser diode of the left sensor and the light receiving element of the adjacent sensor is:

[0105] L2′=L1+2L2+L3+L4+L d

[0106] Where L1 represents the distance between the center of the laser diode and the left shell, L2 represents the distance between the center of the laser diode and the light receiving element, L3 represents the length of the light receiving element, L4 represents the distance between the light receiving element and the right shell, and L d Indicates the spacing between sensors.

[0107] like Figure 4 As shown in (b), from the geometric relationship, we can know that:

[0108]

[0109]

[0110]

[0111] Where θ1′ represents the angle between the focus of the diffusion lens and the vertices on both sides of the virtual image of the adjacent light receiving element, and θ2′ represents the angle between the vertical line from the focus of the diffusion lens to the reflection surface and the vertex on the left side of the virtual image of the adjacent light receiving element. The angle between the focal point of the sensor diffusion lens and the two vertices on the left side of the adjacent light-receiving element. W0 represents the width of the sensor light-receiving element.

[0112] The solid angle of the light beam received by the adjacent light receiving element can be expressed as:

[0113]

[0114] The energy received by the neighboring light receiving element can be expressed as:

[0115]

[0116] (4) Establishing a neutral filter parameter constraint model

[0117] When a neutral filter is installed at the receiving end of the laser displacement sensor, in order to prevent the laser displacement sensor from being interfered by neighboring machines when used in combination, the energy of the light beam received by the sensor's light-receiving element through the filter should be greater than the threshold value T0, that is:

[0118] ηEN1>T0

[0119] The energy of the light beam emitted by the neighboring machine received by the sensor light receiving element through the filter should be less than the threshold value T0, that is:

[0120] ηEN2<T0

[0121] Combining the above two equations, we can get:

[0122]

[0123] Will EN and Substituting into the above formula, the constraint model of the transmittance parameter of the neutral density filter is obtained as follows:

[0124]

[0125] like Figure 5 As shown, the input sensor intrinsic parameters r0, W0, L1, L2, L3, L4, L5, L2′, T0, EN, the focal length of the diffusion lens f0, the measurement distance d and the spacing L between adjacent sensors d , the neutral filter parameter constraint model is used to select a filter that meets the transmittance parameters of the model, and finally the neutral filter is installed in front of the receiving end of the laser displacement sensor.

Claims

1. A laser displacement sensor measuring device suitable for anti-interference of metal surfaces, characterized in that: It includes a housing, a guide rail, a diffusion lens, a neutral density filter and a lens slot; The guide rail is installed in the housing; The diffusion lens is placed in the housing, facing the side of the housing, and is mounted on the inner guide rail of the housing through the lens slot; The neutral density filter and the diffusion lens are placed in parallel and installed in front of the receiving end of the laser displacement sensor; The guide rail is composed of two vertical rods and a horizontal rod. The horizontal rod and the vertical rod are fixed by screws, and the position of the horizontal rod is adjusted according to screw holes with different lengths.

2. A laser displacement sensor measurement method using the measuring device as claimed in claim 1, characterized in that: The steps include: Step 1: Install the housing according to the size of the laser displacement sensor, fix the diffusion lens through the lens slot, adjust the position of the lens slot to ensure that the geometric center of the diffusion lens coincides with the geometric center of the sensor laser diode, and fix it in the screw hole of the guide rail with screws; install the neutral filter to the front of the sensor receiving end so that the filter can completely cover the sensor receiving end; Step 2: Establish a solid angle model of the light beam emitted by the laser diode of the laser displacement sensor, and calculate the total solid angle information of the laser beam after it is diffused by the diffusion lens; Step 3: Establish an optical path model when the laser displacement sensor is used alone, and calculate the solid angle information of the sensor's own light-receiving element; Step 4: Establish an optical path model when the laser displacement sensor is used in combination, and calculate the solid angle information of the light receiving element of the sensor's adjacent machine; Step 5: Calculate the threshold constraints of the laser displacement sensors when used alone and in combination, use the constraints to establish a neutral filter parameter constraint model, then use the model to calculate the transmittance parameters of the filter, and finally place the neutral filter in front of the sensor receiving end.

3. A laser displacement sensor measurement method according to claim 2, characterized in that: The step 2 is specifically as follows: The angle of the beam emitted by the laser diode after passing through the diffusion lens is: Where r0 represents the radius of the circular laser beam emitted by the laser diode, and f0 represents the focal length of the diffusion lens; The differential solid angle of the emitted beam is: Where Ω represents the total solid angle of the emitted laser beam, The total solid angle of the emitted beam is expressed as:

4. A laser displacement sensor measurement method according to claim 3, characterized in that: The step 3 is specifically as follows: From the geometric relationship, we can know that: Where θ1 represents the angle between the focus of the diffusion lens and the two vertices in the front view of the virtual image of the light-receiving element, θ2 represents the angle between the vertical line from the focus of the diffusion lens to the reflecting surface and the left vertex in the front view of the virtual image of the light-receiving element, d represents the measuring distance, L2 represents the horizontal distance from the focus of the diffusion lens to the light-receiving element, and L3 represents the length of the light-receiving element; The angle between the focal point of the diffusion lens and the two vertices of the virtual image of the light receiving element is: Where W0 represents the width of the sensor's light-receiving element; The solid angle of the light beam received by the light receiving element of this machine is expressed as: The energy received by the light-receiving element of this machine is expressed as:

5. A laser displacement sensor measurement method according to claim 4, characterized in that: The step 4 is specifically as follows: Assuming that two laser displacement sensors are installed in parallel, the horizontal distance between the geometric center of the laser diode of the left sensor and the light-receiving element of the adjacent sensor is: <h2 style=";text-align:left;direction:ltr">L2′ = L1 + 2 L2 + L3 + L4 + L<h2 style=";text-align:left;direction:ltr"> d Where L1 represents the distance between the center of the laser diode and the left shell, L2 represents the distance between the center of the laser diode and the light receiving element, L3 represents the length of the light receiving element, L4 represents the distance between the light receiving element and the right shell, and L d Indicates the spacing between sensors; From the geometric relationship, we know that: Where θ1′ represents the angle between the focus of the diffusion lens and the vertices on both sides of the virtual image of the adjacent light receiving element, and θ2′ represents the angle between the vertical line from the focus of the diffusion lens to the reflection surface and the vertex on the left side of the virtual image of the adjacent light receiving element; The angle between the focal point of the sensor diffusion lens and the two vertices on the left side of the adjacent light-receiving element. W0 represents the width of the sensor light-receiving element. The solid angle of the light beam received by the adjacent light receiving element is expressed as: The energy received by the neighboring light receiving element is expressed as:

6. A laser displacement sensor measurement method according to claim 5, characterized in that: The step 5 is specifically as follows: When a neutral filter is installed at the receiving end of the laser displacement sensor, in order to prevent the laser displacement sensor from being interfered by neighboring machines when used in combination, the energy of the light beam received by the sensor's light-receiving element through the filter should be greater than the threshold value T0, that is: ηEN1>T0 The energy of the light beam emitted by the neighboring machine received by the sensor light receiving element through the filter should be less than the threshold value T0, that is: ηEN2<T0 Combining the above two equations, we get: Will and Substituting EN into the above formula, the constraint model of the neutral density filter transmittance parameter is obtained as follows: Input sensor intrinsic parameters r0, W0, L1, L2, L3, L4, L5, L2′, T0, EN, diffusion lens focal length f0, measurement distance d and spacing L between adjacent sensors d , the neutral filter parameter constraint model is used to select a filter that meets the transmittance parameters of the model, and finally the neutral filter is installed in front of the receiving end of the laser displacement sensor.

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