Sensor device

Abstract

The deviation of the scanning range of the scanning unit from the reference position is measured appropriately. [Solution] Four reflective sections (200) are located at the four corners of the scanning range (SA): the first corner (CR1), the second corner (CR2), the third corner (CR3), and the fourth corner (CR4). Each reflective section (200) reflects at least a portion of the spot (S). The measuring section (310) measures the deviation of the scanning section (100) from the reference position using the relationship between the amount of reflection A1 of the spot (S) reflected by the reflective section (200) located at the first corner (CR1), the amount of reflection A2 of the spot (S) reflected by the reflective section (200) located at the second corner (CR2), the amount of reflection A3 of the spot (S) reflected by the reflective section (200) located at the third corner (CR3), and the amount of reflection A4 of the spot (S) reflected by the reflective section (200) located at the fourth corner (CR4).

Description

[Technical Field]

[0001] This invention relates to a sensor device. [Background technology]

[0002] In recent years, various sensor devices such as LiDAR (Light Detection and Ranging) have been developed. These sensor devices are equipped with scanning units such as MEMS (Micro Electro Mechanical Systems) mirrors and polygon mirrors.

[0003] Patent Document 1 describes an example of a sensor device. In this sensor device, reflective sections are provided at the scanning start position and the scanning end position of the scanning unit. Furthermore, the positional shift of the scanning range is measured by comparing the amount of reflection of the beam reflected by the reflective section provided at the scanning start position with the amount of reflection of the beam reflected by the reflective section provided at the scanning end position. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-16481 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] For example, as described in Patent Document 1, the deviation of the scanning range may be measured by using the amount of reflection of the beam reflected by a reflector located at the starting position of scanning within the scanning range of the scanning unit, and the amount of reflection of the beam reflected by a reflector located at the ending position of scanning within the scanning range of the scanning unit. However, using only two reflectors may not be sufficient to measure the rotational deviation of the scanning range. Furthermore, when the scanning range is shifted by a relatively large distance, the beam may not illuminate the reflector located at the starting position or the reflector located at the ending position of scanning.

[0006] One example of a problem that the present invention aims to solve is the appropriate measurement of the deviation of the scanning range of the scanning unit from a reference position. [Means for solving the problem]

[0007] The invention described in claim 1 is, Scanning unit and, A plurality of reflectors that reflect at least a portion of the beam irradiated onto the scanning range of the scanning unit, Equipped with, The sensor device is such that the plurality of reflective parts are located at at least four corners of the scanning range.

[0008] One aspect of the present invention is, Scanning unit and, A plurality of reflectors that reflect at least a portion of the beam irradiated onto the scanning range of the scanning unit, Equipped with, The plurality of reflective portions are located on at least both sides of the scanning range, The sensor device is such that the plurality of reflectors reflect at least a portion of the beam that is different from the beam that is irradiated at the starting position of scanning the scanning range of the scanning unit and the beam that is irradiated at the ending position of scanning the scanning range of the scanning unit. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of the sensor device according to the embodiment. [Figure 2] This figure shows an example of the relationship between the scanning range of the scanning unit and multiple reflective units. [Figure 3] This diagram illustrates the first example of a deviation of the scanning unit's position from its reference position. [Figure 4] This diagram illustrates a second example of the deviation of the scanning unit's position from its reference position. [Figure 5] This diagram illustrates a third example of the deviation of the scanning unit's position from its reference position. [Figure 6] It is a diagram showing a first modification example of FIG. 2. [Figure 7] It is a diagram showing a second modification example of FIG. 2. [Figure 8] It is a diagram showing a third modification example of FIG. 2. [Figure 9] It is a diagram showing a fourth modification example of FIG. 2. [Figure 10] It is a diagram illustrating the hardware configuration of the measurement unit and the correction unit. [Figure 11] It is a diagram for explaining a first example of a measurement system that measures the deviation of the scanning unit from the reference position. [Figure 12] It is a diagram for explaining a second example of a measurement system that measures the deviation of the scanning unit from the reference position. [Figure 13] It is a diagram for explaining a third example of a measurement system that measures the deviation of the scanning unit from the reference position. [Figure 14] It is a diagram for explaining a fourth example of a measurement system that measures the deviation of the scanning unit from the reference position.

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

[0011] In this specification, ordinal numbers such as "first", "second", "third", etc. are given for the sole purpose of simply distinguishing configurations with the same name, unless otherwise specified, and do not mean specific features of the configuration (for example, order or importance).

[0012] FIG. 1 is a perspective view of the sensor device 10 according to the embodiment. FIG. 2 is a diagram showing an example of the relationship between the scanning range SA of the scanning unit 100 and the plurality of reflection units 200.

[0013] In Figures 1 and 2, the arrows indicating the first direction X, the second direction Y, or the third direction Z indicate that the direction from the base to the tip of the arrow is the positive direction of the direction indicated by the arrow, and the direction from the tip to the base of the arrow is the negative direction of the direction indicated by the arrow. The white circle with a black dot indicating the third direction Z indicates that the direction from the back to the front of the page is the positive direction of the direction indicated by the white circle with a black dot, and the direction from the front to the back of the page is the negative direction of the direction indicated by the white circle with a black dot.

[0014] The first direction X is a single direction parallel to the horizontal direction and perpendicular to the vertical direction. Viewed from the positive direction of the third direction Z, the positive direction of the first direction X is horizontal from left to right, and the negative direction of the first direction X is horizontal from right to left. The second direction Y is a direction parallel to the vertical direction. The positive direction of the second direction Y is vertical from bottom to top, and the negative direction of the second direction Y is vertical from top to bottom. The third direction Z is a single direction parallel to the horizontal direction and perpendicular to the first direction X. Viewed from the negative direction of the first direction X, the positive direction of the third direction Z is horizontal from left to right, and the negative direction of the third direction Z is horizontal from right to left.

[0015] The relationships between the first direction X, the second direction Y, the third direction Z, the horizontal direction, and the vertical direction are not limited to those in this embodiment. The relationships between the first direction X, the second direction Y, the third direction Z, the horizontal direction, and the vertical direction vary depending on the arrangement of the sensor device 10. For example, the third direction Z may be parallel to the vertical direction.

[0016] The sensor device 10 comprises a housing 12, a scanning unit 100, a plurality of reflective units 200, a measuring unit 310, and a correction unit 320.

[0017] The scanning unit 100 is housed inside the housing 12. In this embodiment, the scanning unit 100 is a two-axis MEMS mirror. The scanning unit 100 may be a different scanning unit from the two-axis MEMS mirror, for example, a galvanometer mirror.

[0018] The scanning unit 100 scans the beam in the first direction X and the second direction Y on a virtual plane perpendicular to the third direction Z. Specifically, the scanning unit 100 has a reflecting surface 102 that reflects a beam emitted from a light source such as a laser (not shown). In Figure 1, the dashed arrows extending toward the reflecting surface 102 indicate the optical axis of the beam emitted from the light source (not shown) and incident on the reflecting surface 102. In Figure 1, each of the two dashed arrows extending from the reflecting surface 102 indicates the optical axis of the beam reflected by the reflecting surface 102. The two beams indicated by these two dashed arrows are reflected by the reflecting surface 102 at different timings.

[0019] The reflective surface 102 rotates around a yaw axis 102y and a pitch axis 102p, which are orthogonal to each other. The yaw axis 102y and the pitch axis 102p are orthogonal to a roll axis 102r that passes through the normal at the center of the reflective surface 102. When the scanning unit 100 is in the reference position, the yaw axis 102y is tilted obliquely toward the negative direction of the third direction Z with respect to the positive direction of the second direction Y. Also, when the scanning unit 100 is in a predetermined reference position, the pitch axis 102p is parallel to the first direction X. The scanning unit 100 scans the beam incident on the reflective surface 102 in the first direction X on a virtual plane perpendicular to the third direction Z by rotating the reflective surface 102 around the yaw axis 102y. The scanning unit 100 also scans the beam incident on the reflective surface 102 in the second direction Y on a virtual plane perpendicular to the third direction Z by rotating the reflective surface 102 around the pitch axis 102p.

[0020] In this embodiment, the reference position of the scanning unit 100 refers to the position where the scanning unit 100 would be located if it were positioned as designed. For example, when assembling the scanning unit 100 to the sensor device 10, the scanning unit 100 is positioned at the reference position by fixing means such as adhesive. However, positioning the scanning unit 100 at the reference position requires relatively high-precision adjustment and can be relatively costly. Furthermore, even if the scanning unit 100 is positioned at the reference position by fixing means, the position of the scanning unit 100 may shift from the reference position due to changes in the fixing means over time.

[0021] The scanning unit 100 scans a predetermined scanning range SA projected onto a virtual plane perpendicular to the third direction Z using a beam. Specifically, the sensor device 10 generates point cloud data by detecting the beam, which is irradiated by the scanning unit 100 toward the scanning range SA and reflected or scattered by an object (not shown) located outside the housing 12, using an optical detection element such as an APD (avalanche photodiode) (not shown).

[0022] Figures 1 and 2 show the scanning range SA projected onto a virtual plane perpendicular to the third direction Z at a predetermined location in the housing 12, such as a window that allows the beam irradiated by the scanning unit 100 to pass through. The scanning range SA is irradiated by the scanning unit 100. Hereafter, as needed, the portion of the beam irradiated by the scanning unit 100 that is projected onto the same virtual plane as the virtual plane onto which the scanning range SA is projected will be called a spot. The scanning range SA shown in Figures 1 and 2 schematically represents the region occupied by the trajectory through which the center of the spot generated by the beam scanned by the scanning unit 100 passes, and the portion of that trajectory adjacent to the second direction Y. Figures 1 and 2 show the four spots S located at the four corners of the scanning range SA, namely the first corner CR1, the second corner CR2, the third corner CR3, and the fourth corner CR4, which will be described later.

[0023] In Figures 1 and 2, for illustrative purposes, a first virtual line LX and a second virtual line LY are shown in the scanning range SA. The first virtual line LX is a virtual line that passes through the center of the scanning range SA parallel to the first direction X when the scanning unit 100 is in the reference position. The second virtual line LY is a virtual line that passes through the center of the scanning range SA parallel to the second direction Y when the scanning unit 100 is in the reference position.

[0024] In this embodiment, the scanning range SA has four corners, a first corner CR1, a second corner CR2, a third corner CR3, and a fourth corner CR4, and has a shape that approximates a sector. The shape of the scanning range SA is not limited to a shape that approximates a sector, and may be a shape other than a sector, such as a rectangle, a square, or other quadrilateral or a shape that approximates a quadrilateral. When viewed from the positive side of the third direction Z, the first corner CR1 is located on the negative side of the first direction X with respect to the second virtual line LY and on the positive side of the second direction Y with respect to the first virtual line LX. When viewed from the third direction Z, the second corner CR2 is located on the positive side of the first direction X with respect to the second virtual line LY and on the positive side of the second direction Y with respect to the first virtual line LX. When viewed from the third direction Z, the third corner CR3 is located on the negative side of the first direction X with respect to the second virtual line LY and on the negative side of the second direction Y with respect to the first virtual line LX. Viewed from the third direction Z, the fourth angle CR4 is located on the positive side of the first direction X relative to the second virtual line LY, and on the negative side of the second direction Y relative to the first virtual line LX.

[0025] The scanning unit 100 starts scanning each frame of the scanning range SA from the first corner CR1 or the second corner CR2. For example, if scanning starts from the first corner CR1, the reflective surface 102 is rotated around the yaw axis 102y in the positive direction of the first direction X to scan the stage between the first corner CR1 and the second corner CR2 of the scanning range SA. After scanning the stage between the first corner CR1 and the second corner CR2 of the scanning range SA is completed, the reflective surface 102 is rotated around the pitch axis 102p in the negative direction of the second direction Y, and then the reflective surface 102 is rotated around the yaw axis 102y to scan the stage located on the negative side of the second direction Y relative to the previously scanned stage. In this way, the scanning unit 100 repeats scanning of multiple stages aligned in the second direction Y of the scanning range SA. The rotation direction of the yaw axis 102y when scanning a certain step within the scanning range SA and the rotation direction of the yaw axis 102y when scanning another step within the scanning range SA adjacent to that step in the second direction Y may be the same or opposite. At the final stage of each frame within the scanning range SA, the scanning unit 100 scans the step between the third corner CR3 and the fourth corner CR4 within the scanning range SA. As a result, the scanning unit 100 terminates scanning of each frame within the scanning range SA at the third corner CR3 or the fourth corner CR4.

[0026] Figure 3 is a diagram illustrating a first example of the deviation of the scanning unit 100 from its reference position.

[0027] In Figure 3, the scanning range SA shown by the solid line represents the scanning range projected onto a virtual plane perpendicular to the third direction Z when the scanning unit 100 is in its reference position. The scanning range SA shown by the dashed line represents the scanning range projected onto a virtual plane perpendicular to the third direction Z when the scanning unit 100 is rotated around the yaw axis 102y in the negative direction of the first direction X, compared to when the scanning unit 100 is in its reference position. As shown in Figure 3, the scanning range SA when the scanning unit 100 is rotated around the yaw axis 102y in the negative direction of the first direction X, compared to when the scanning unit 100 is in its reference position, is not only moved from the scanning range SA when the scanning unit 100 is in its reference position, but is also deformed.

[0028] Figure 4 illustrates a second example of the deviation of the scanning unit 100 from its reference position.

[0029] In Figure 4, the scanning range SA shown by the solid line represents the scanning range projected onto a virtual plane perpendicular to the third direction Z when the scanning unit 100 is in its reference position. The scanning range SA shown by the dashed line represents the scanning range projected onto a virtual plane perpendicular to the third direction Z when the scanning unit 100 is rotated around the pitch axis 102p in the positive direction of the second direction Y, compared to when the scanning unit 100 is in its reference position. As shown in Figure 4, the scanning range SA when the scanning unit 100 is rotated around the pitch axis 102p in the positive direction of the second direction Y, compared to when the scanning unit 100 is in its reference position, is not only moved from the scanning range SA when the scanning unit 100 is in its reference position, but is also deformed.

[0030] Figure 5 illustrates a third example of the deviation of the scanning unit 100 from its reference position.

[0031] In Figure 5, the scanning range SA shown by the solid line represents the scanning range projected onto a virtual plane perpendicular to the third direction Z when the scanning unit 100 is in its reference position. The scanning range SA shown by the dashed line represents the scanning range projected onto a virtual plane perpendicular to the third direction Z when the scanning unit 100 is rotated clockwise around the roll axis 102r as viewed from the positive direction of the third direction Z, compared to when the scanning unit 100 is in its reference position. As shown in Figure 5, the scanning range SA when the scanning unit 100 is rotated clockwise around the roll axis 102r as viewed from the positive direction of the third direction Z, compared to when the scanning unit 100 is in its reference position, is not only shifted from the scanning range SA when the scanning unit 100 is in its reference position, but is also deformed.

[0032] Return to Figures 1 and 2.

[0033] In this embodiment, the four reflective sections 200 are located at the four corners of the scanning range SA: the first corner CR1, the second corner CR2, the third corner CR3, and the fourth corner CR4. Each reflective section 200 reflects at least a portion of the spot S. In addition to the four reflective sections 200 shown in Figures 1 and 2, the sensor device 10 may further include other reflective sections 200.

[0034] The measuring unit 310 measures the deviation of the scanning unit 100 from the reference position using the relationship between the amount of reflection A1 of the spot S reflected by the reflector 200 provided at the first corner CR1, the amount of reflection A2 of the spot S reflected by the reflector 200 provided at the second corner CR2, the amount of reflection A3 of the spot S reflected by the reflector 200 provided at the third corner CR3, and the amount of reflection A4 of the spot S reflected by the reflector 200 provided at the fourth corner CR4.

[0035] Firstly, the measuring unit 310 uses the comparison result of the sum of A1 and A3 and the sum of A2 and A4 to measure the deviation of the scanning unit 100 from the reference position due to the rotation of the reflective surface 102 around the yaw axis 102y. For example, when the scanning unit 100 is at the reference position, the ratio {(A1+A3)-(A2+A4)} / {(A1+A3)+(A2+A4)} is a known reference value. In this case, when the above ratio is greater than the above reference value, the measuring unit 310 can measure that the scanning range SA is shifted in the negative direction of the first direction X compared to when the scanning unit 100 is at the reference position. On the other hand, when the above ratio is smaller than the above reference value, the measuring unit 310 can measure that the scanning range SA is shifted in the positive direction of the first direction X compared to when the scanning unit 100 is at the reference position. In particular, when multiple reflective sections 200 are provided such that the above reference value is zero, it is easier to determine whether the ratio is greater than or less than the above reference value based solely on the sign of the ratio, compared to when the above reference value is a value other than zero. From this viewpoint, it is preferable that the above reference value is zero. However, the above reference value may be a value other than zero.

[0036] Secondly, the measuring unit 310 uses the comparison result of the sum of A1 and A2 and the sum of A3 and A4 to measure the deviation of the scanning unit 100 from the reference position due to the rotation of the reflective surface 102 around the pitch axis 102p. For example, when the scanning unit 100 is at the reference position, the ratio {(A1+A2)-(A3+A4)} / {(A1+A2)+(A3+A4)} is a known reference value. In this case, when the above ratio is greater than the above reference value, the measuring unit 310 can measure that the scanning range SA is shifted in the positive direction of the second direction Y compared to when the scanning unit 100 is at the reference position. On the other hand, when the above ratio is smaller than the above reference value, the measuring unit 310 can measure that the scanning range SA is shifted in the negative direction of the second direction Y compared to when the scanning unit 100 is at the reference position. In particular, when multiple reflective sections 200 are provided such that the above reference value is zero, it is easier to determine whether the ratio is greater than or less than the above reference value based solely on the sign of the ratio, compared to when the above reference value is a value other than zero. From this viewpoint, it is preferable that the above reference value is zero. However, the above reference value may be a value other than zero.

[0037] Thirdly, the measuring unit 310 uses the comparison result of the relative value of A1 with respect to A3 and the relative value of A4 with respect to A2 to measure the deviation of the scanning unit 100's position from the reference position due to the rotation of the reflective surface 102 around the roll axis 102r. For example, when the scanning unit 100 is in the reference position, the ratio (A1-A3) / (A1+A3)+(A4-A2) / (A4+A2) is a known reference value. In this case, when the above ratio is greater than the above reference value, the measuring unit 310 can measure that the scanning range SA has rotated counterclockwise when viewed from the positive direction of the third direction Z compared to when the scanning unit 100 is in the reference position. On the other hand, when the above ratio is smaller than the above reference value, the measuring unit 310 can measure that the scanning range SA has rotated clockwise when viewed from the positive direction of the third direction Z compared to when the scanning unit 100 is in the reference position. In particular, when multiple reflective sections 200 are provided such that the above reference value is zero, it is easier to determine whether the ratio is greater than or less than the above reference value based solely on the sign of the ratio, compared to when the above reference value is a value other than zero. From this viewpoint, it is preferable that the above reference value is zero. However, the above reference value may be a value other than zero.

[0038] In the example shown in Figure 2, the starting position of scanning the scanning range SA of the scanning unit 100 is the first corner CR1 or the second corner CR2, and the ending position of scanning the scanning range SA of the scanning unit 100 is the third corner CR3 or the fourth corner CR4. Therefore, two of the four reflectors 200 located at the first corner CR1, the second corner CR2, the third corner CR3, and the fourth corner CR4 reflect at least a portion of a different spot S: the spot S irradiated at the starting position of scanning the scanning range SA of the scanning unit 100 and the spot S irradiated at the ending position of scanning the scanning range SA of the scanning unit 100. For example, if the scanning start position and scanning end position of the scanning range SA of the scanning unit 100 are the first corner CR1 and the third corner CR3, respectively, and the reflecting units 200 are located at only two locations, the first corner CR1 and the third corner CR3, then if the scanning range SA is shifted by a relatively large distance in the positive direction of the first direction X compared to when the scanning unit 100 is at its reference position, the spot S may not illuminate the two reflecting units 200 located at the first corner CR1 and the third corner CR3. In contrast, in the example shown in Figure 2, even if the scanning range SA is shifted by a relatively large distance compared to when the scanning unit 100 is at its reference position, at least a portion of the spot S can be illuminated at least one of the four reflecting units 200.

[0039] Figure 6 shows the first modified example of Figure 2. The modified example shown in Figure 6 is the same as the embodiment shown in Figure 2, except for the following points.

[0040] In the modified example shown in Figure 6, the two reflective sections 200 are located on both sides of the second direction Y of the scanning range SA. Furthermore, the two reflective sections 200 are located on the second virtual line LY. In addition to the two reflective sections 200 shown in Figure 6, the sensor device 10 may further include other reflective sections 200.

[0041] The measuring unit 310 uses the result of comparing the amount of reflection A5 of the spot S reflected by the reflecting unit 200 located on the positive side of the second direction Y with respect to the first virtual line LX, and the amount of reflection A6 of the spot S reflected by the reflecting unit 200 located on the negative side of the second direction Y with respect to the first virtual line LX, to measure the deviation of the position of the scanning unit 100 from the reference position due to the rotation of the reflective surface 102 around the pitch axis 102p. For example, when the position of the scanning unit 100 is at the reference position, the ratio (A5-A6) / (A5+A6) is assumed to be a known reference value. In this case, when the above ratio is greater than the above reference value, the measuring unit 310 can measure that the scanning range SA is shifted in the positive direction of the second direction Y compared to when the position of the scanning unit 100 is at the reference position. On the other hand, when the above ratio is smaller than the above reference value, the measuring unit 310 can measure that the scanning range SA is shifted in the negative direction of the second direction Y compared to when the position of the scanning unit 100 is at the reference position. In particular, when multiple reflective sections 200 are provided such that the above reference value is zero, it is easier to determine whether the ratio is greater than or less than the above reference value based solely on the sign of the ratio, compared to when the above reference value is a value other than zero. From this viewpoint, it is preferable that the above reference value is zero. However, the above reference value may be a value other than zero.

[0042] In the example shown in Figure 6, the scanning start position of the scanning range SA of the scanning unit 100 is at the first corner CR1 or the second corner CR2, and the scanning end position of the scanning range SA of the scanning unit 100 is at the third corner CR3 or the fourth corner CR4. Therefore, the two reflectors 200 reflect at least a portion of a different spot S: the spot S irradiated at the scanning start position of the scanning range SA of the scanning unit 100 and the spot S irradiated at the scanning end position of the scanning range SA of the scanning unit 100. For example, if the scanning start position and the scanning end position of the scanning range SA of the scanning unit 100 are at the first corner CR1 and the third corner CR3, respectively, and the two reflectors 200 are located at the first corner CR1 and the third corner CR3, then if the scanning range SA is shifted by a relatively large distance in the positive direction of the first direction X compared to when the scanning unit 100 is at its reference position, the spot S may not be irradiated onto the two reflectors 200 located at the first corner CR1 and the third corner CR3. In contrast, in the example shown in Figure 6, even if the scanning range SA is shifted by a relatively large distance in the first direction X compared to when the scanning unit 100 is at the reference position, at least a portion of the spot S can be irradiated onto both of the two reflecting units 200.

[0043] Figure 7 shows a second modified example of Figure 2. The modified example shown in Figure 7 is the same as the modified example shown in Figure 6, except for the following points.

[0044] In the modified example shown in Figure 7, the two reflective sections 200 are positioned offset to the negative side of the first direction X with respect to the second virtual line LY. The two reflective sections 200 may also be positioned offset to the positive side of the first direction X with respect to the second virtual line LY. In the modified example shown in Figure 7, as in the modified example shown in Figure 6, the measuring unit 310 can measure the displacement of the scanning unit 100 from its reference position due to the rotation of the reflective surface 102 around the pitch axis 102p. Also, as in the modified example shown in Figure 6, even if the scanning range SA is shifted by a relatively large distance in the first direction X compared to when the scanning unit 100 is at its reference position, at least a portion of the spot S can be irradiated onto both of the two reflective sections 200.

[0045] Figure 8 shows a third modified example of Figure 2. The modified example shown in Figure 8 is the same as the embodiment shown in Figure 2, except for the following points.

[0046] In the modified example shown in Figure 8, the two reflective sections 200 are located on both sides of the first direction X of the scanning range SA. Furthermore, the two reflective sections 200 are located on the first virtual line LX. In addition to the two reflective sections 200 shown in Figure 8, the sensor device 10 may further include other reflective sections 200.

[0047] The measuring unit 310 uses the result of comparing the amount of reflection A7 of the spot S reflected by the reflecting unit 200 located on the positive side of the first direction X with respect to the second virtual line LY, and the amount of reflection A8 of the spot S reflected by the reflecting unit 200 located on the negative side of the first direction X with respect to the second virtual line LY, to measure the deviation of the position of the scanning unit 100 from the reference position due to the rotation of the reflective surface 102 around the yaw axis 102y. For example, when the position of the scanning unit 100 is at the reference position, the ratio (A7-A8) / (A7+A8) is assumed to be a known reference value. In this case, when the above ratio is greater than the above reference value, the measuring unit 310 can measure that the scanning range SA is shifted in the positive direction of the first direction X compared to when the position of the scanning unit 100 is at the reference position. On the other hand, when the above ratio is smaller than the above reference value, the measuring unit 310 can measure that the scanning range SA is shifted in the negative direction of the first direction X compared to when the position of the scanning unit 100 is at the reference position. In particular, when multiple reflective sections 200 are provided such that the above reference value is zero, it is easier to determine whether the ratio is greater than or less than the above reference value based solely on the sign of the ratio, compared to when the above reference value is a value other than zero. From this viewpoint, it is preferable that the above reference value is zero. However, the above reference value may be a value other than zero.

[0048] In the example shown in Figure 8, the starting position of scanning range SA of the scanning unit 100 is the first corner CR1 or the second corner CR2, and the ending position of scanning range SA of the scanning unit 100 is the third corner CR3 or the fourth corner CR4. Therefore, the two reflectors 200 reflect at least a portion of a different spot S: the spot S irradiated at the starting position of scanning range SA of the scanning unit 100 and the spot S irradiated at the ending position of scanning range SA of the scanning unit 100. If the two reflectors 200 are located at the starting position and the ending position of scanning range SA of the scanning unit 100, then when the scanning range SA is shifted by a relatively large distance in the second direction Y compared to when the scanning unit 100 is at its reference position, the spot S may not be irradiated onto at least one of the two reflectors 200. In contrast, in the example shown in Figure 6, even if the scanning range SA is shifted by a relatively large distance in the second direction Y compared to when the scanning unit 100 is at the reference position, at least a portion of the spot S can be irradiated onto both of the two reflecting units 200.

[0049] Figure 9 shows the fourth modified version of Figure 2. The modified version shown in Figure 9 is the same as the modified version shown in Figure 8, except for the following points.

[0050] In the modified example shown in Figure 9, the two reflectors 200 are positioned offset to the negative side of the second direction Y with respect to the first virtual line LX. The two reflectors 200 may also be positioned offset to the positive side of the second direction Y with respect to the first virtual line LX. In the modified example shown in Figure 9, as in the modified example shown in Figure 8, the measuring unit 310 can measure the displacement of the scanning unit 100 from its reference position due to the rotation of the reflective surface 102 around the yaw axis 102y. Also, as in the modified example shown in Figure 8, even if the scanning range SA is shifted by a relatively large distance in the second direction Y compared to when the scanning unit 100 is at its reference position, at least a portion of the spot S can be irradiated onto both of the two reflectors 200.

[0051] Returning to Figure 1, let's explain the correction unit 320.

[0052] The correction unit 320 corrects the data indicating the measurement direction of the scanning unit 100 according to the deviation of the scanning unit 100's position from the reference position.

[0053] Assume that the scanning unit 100 is at the reference position. In this case, let n0 be the unit normal vector of the reflective surface 102 when the reflective surface 102 is stationary, and let n be the unit direction vector in the direction parallel to the yaw axis 102y. y Let n be the unit direction vector in the direction parallel to the pitch axis 102p. p Let's assume that the reflective surface 102 moves from a stationary state to an angle θ around the yaw axis 102y. y,1 It rotates and around the pitch axis 102p at an angle θ p,1 When rotated, the normal vector n1 of the reflective surface 102 becomes as shown in equation (1) below.

number

number

[0054] When a beam with direction vector r is incident on a reflecting surface 102 whose normal vector is the normal vector n1 shown in equation (1), the direction vector of the beam reflected by the reflecting surface 102, that is, the direction vector m1 of the measurement direction of the scanning unit 100, is as shown in equation (3) below.

number

[0055] Compared to when the scanning unit 100 is in the reference position, the reflective surface 102 is at an angle Δθ around the roll axis 102r. r , angle Δθ around the yaw axis 102y y , around the pitch axis 102p at an angle Δθp Assume the case where rotation occurs in the order of the roll axis 102r, the yaw axis 102y, and the pitch axis 102p. Hereinafter, as necessary, when the position of the scanning unit 100 is at the reference position, the reflection surface 102 is at an angle Δθ around the roll axis 102r compared with that r and at an angle Δθ around the yaw axis 102y <00OOOO1O>and at an angle Δθ around the pitch axis 102p. p The rotation in the order of the roll axis 102r, the yaw axis 102y, and the pitch axis 102p is referred to as the reflection surface 102 being at a rotational displacement position.

[0056] When the reflection surface 102 is at a rotational displacement position and in a stationary state, the unit normal vector n0´ of the reflection surface 102, the unit direction vector n y ´ in the direction parallel to the yaw axis, and the unit direction vector n p ´ in the direction parallel to the pitch axis are obtained by rotating the vector n0, the vector n y and the vector n p by an angle Δθ around the roll axis 102r r and by an angle Δθ around the yaw axis 102y y and by an angle Δθ around the pitch axis 102p p in the order of the roll axis 102r, the yaw axis 102y, and the pitch axis 102p.

[0057] In equations (1), (2), and (3), by replacing the vector n0, the vector n y and the vector n p with the vector n0´, the vector n y ´, and the vector n p ´ respectively, the direction vector m´ of the measurement direction of the scanning unit 100 when the reflection surface 102 is at a rotational displacement position can be calculated.

[0058] If, for example, the reflective surface 102 is in a rotationally misaligned position, but the data indicating the measurement direction of the scanning unit 100 has not been replaced from direction vector m to direction vector m', the sensor device 10 will incorrectly detect an object located in the direction of direction vector m' as an object located in the direction of direction vector m. In contrast, in this embodiment, the correction unit 320 corrects the data indicating the measurement direction of the scanning unit 100 from direction vector m to direction vector m'. This allows the sensor device 10 to accurately detect the direction in which an object is located. Furthermore, when the data indicating the measurement direction of the scanning unit 100 is corrected by the correction unit 320, high-precision adjustment to position the scanning unit 100 at a reference position becomes unnecessary when assembling the scanning unit 100 into the sensor device 10. In this case, the cost of assembling the scanning unit 100 into the sensor device 10 can be reduced compared to the case where high-precision adjustment is required.

[0059] Figure 10 illustrates the hardware configuration of the measurement unit 310 and the correction unit 320. The measurement unit 310 and the correction unit 320 are implemented using an integrated circuit 400. The integrated circuit 400 is, for example, a SoC (System-on-a-Chip).

[0060] The integrated circuit 400 includes a bus 402, a processor 404, a memory 406, a storage device 408, an input / output interface 410, and a network interface 412. The bus 402 is a data transmission path for the processor 404, memory 406, storage device 408, input / output interface 410, and network interface 412 to send and receive data to and from each other. However, the method of connecting the processor 404, memory 406, storage device 408, input / output interface 410, and network interface 412 to each other is not limited to bus connection. The processor 404 is an arithmetic processing unit implemented using a microprocessor or the like. The memory 406 is a memory implemented using RAM (Random Access Memory) or the like. The storage device 408 is a storage device implemented using ROM (Read Only Memory) or flash memory or the like.

[0061] The input / output interface 410 is an interface for connecting the integrated circuit 400 to peripheral devices. The scanning unit 100 is connected to the input / output interface 410.

[0062] The network interface 412 is an interface for connecting the integrated circuit 400 to a network. This network is, for example, a CAN (Controller Area Network) network. The network interface 412 may connect to the network via a wireless connection or a wired connection.

[0063] The storage device 408 stores program modules for realizing the functions of the measurement unit 310 and program modules for realizing the functions of the correction unit 320. The processor 404 reads these program modules into the memory 406 and executes them to realize the respective functions of the measurement unit 310 and the correction unit 320.

[0064] The hardware configuration of the integrated circuit 400 is not limited to the configuration shown in Figure 10. For example, the program module may be stored in the memory 406. In this case, the integrated circuit 400 does not need to have a storage device 408.

[0065] Figure 11 is a diagram illustrating a first example of a measurement system 50A for measuring the deviation of the scanning unit 100 from a reference position.

[0066] The measurement system 50A comprises a screen 500A and an imaging unit 510A. The screen 500A is a plane perpendicular to the third direction Z. For illustrative purposes, a first virtual line LXA and a second virtual line LYA are shown in the measurement system 50A. The first virtual line LXA is a virtual line passing through the center of the screen 500A parallel to the first direction X. The second virtual line LYA is a virtual line passing through the center of the screen 500A parallel to the second direction Y.

[0067] The imaging unit 510A captures the beam spot generated when the beam irradiated by the scanning unit 100 is projected onto the screen 500A. The measurement system 50A uses the imaging results from the imaging unit 510A to measure the deviation of the scanning unit 100 from its reference position.

[0068] The measurement of the deviation of the scanning unit 100's position from its reference position due to rotation around at least one of its pitch axis 102p and yaw axis 102y will be described. Assume that the scanning unit 100 is stationary. In this case, when the scanning unit 100 is at its reference position, a beam emitted from a light source such as a laser (not shown) is incident on the reflective surface 102, as indicated by the dashed arrows extending toward the reflective surface 102 in Figure 11. The beam incident on the reflective surface 102 is projected by the scanning unit 100 onto the center of the screen 500A, i.e., the intersection of the first virtual line LXA and the second virtual line LYA in the screen 500A, as indicated by the first dashed arrow AR1 extending from the reflective surface 102 toward the intersection of the first virtual line LXA and the second virtual line LYA in the screen 500A, as indicated by the first dashed arrow AR1 extending shown by the scanning unit 100. When the scanning unit 100 is stationary, and its position shifts from its reference position due to rotation of at least one of the pitch axis 102p and yaw axis 102y of the reflective surface 102, the beam projected onto the screen 500A by the scanning unit 100 will be shifted from the center of the screen 500A, for example, as shown by the second dashed arrow AR2 in Figure 11, which extends from the reflective surface 102 to a position shifted in the positive direction of the first direction X and the positive direction of the second direction Y with respect to the intersection of the first virtual line LXA and the second virtual line LYA on the screen 500A. The imaging unit 510A captures the beam spot projected at a position shifted from the center of the screen 500A. The measurement system 50A can use the imaging results from the imaging unit 510A to measure the shift of the scanning unit 100's position from its reference position due to rotation around at least one of the pitch axis 102p and yaw axis 102y of the reflective surface 102.

[0069] This section describes the measurement of the deviation of the scanning unit 100's position from its reference position due to rotation of the scanning unit 100 around its roll axis 102r. Assume the case where the reflective surface 102 is rotated around the pitch axis 102p instead of the yaw axis 102y. In this case, when the scanning unit 100 is at its reference position, a beam incident on the reflective surface 102 from a light source (not shown, such as a laser) is projected onto the second virtual line LYA by the scanning unit 100. Similarly, assume the case where the reflective surface 102 is rotated around the pitch axis 102p instead of the yaw axis 102y. In this case, if the scanning unit 100's position deviates from its reference position due to rotation of the scanning unit 100 around its roll axis 102r, the trajectory of the beam spot projected onto the screen 500A by the scanning unit 100 is tilted with respect to the second virtual line LYA. The imaging unit 510A captures the trajectory of the beam spot tilted from the second virtual line LYA. The measurement system 50A can measure the deviation of the scanning unit 100 from its reference position due to the rotation of the reflective surface 102 around the roll axis 102r, using the imaging results from the imaging unit 510A.

[0070] Figure 12 is a diagram illustrating a second example of a measurement system 50B that measures the deviation of the scanning unit 100 from a reference position.

[0071] In Figure 12, the scanning range SA shown by the solid line represents the scanning range projected onto the screen 500B by the scanning unit 100 when the scanning unit 100 is in the reference position. The scanning range SA shown by the dashed line represents the scanning range projected onto the screen 500B by the scanning unit 100 when the scanning unit 100 is deviated from the reference position. The screen 500B is a plane perpendicular to the third direction Z.

[0072] The imaging unit 510B images the scanning range SA projected onto the screen 500B by the scanning unit 100. The measurement system 50B uses the imaging results from the imaging unit 510B to measure the deviation of the scanning unit 100 from its reference position. Specifically, the measurement system 50B can measure the deviation of the scanning unit 100 from its reference position by comparing the scanning range SA projected onto the screen 500B by the scanning unit 100 when the scanning unit 100 is at its reference position with the scanning range SA projected onto the screen 500B when the scanning unit 100 is shifted from its reference position, using the imaging results from the imaging unit 510B. When the imaging unit 510B images the scanning range SA projected onto the screen 500B, the sensor device 10 may irradiate the entire scanning range SA on the screen 500B with a pulsed beam, or it may irradiate only a portion of the scanning range SA on the screen 500B with a pulsed beam.

[0073] Figure 13 is a diagram illustrating a third example of a measurement system 50C that measures the deviation of the scanning unit 100 from a reference position.

[0074] In Figure 13, the scanning range SA shown by the solid line represents the scanning range projected onto the screen 500C by the scanning unit 100 when the scanning unit 100 is in the reference position. The scanning range SA shown by the dashed line represents the scanning range projected onto the screen 500C by the scanning unit 100 when the scanning unit 100 is deviated from the reference position. The screen 500C is a plane perpendicular to the third direction Z.

[0075] The screen 500C has a first region 502C and a second region 504C. In at least a portion of the screen 500C, the first region 502C and the second region 504C are regularly arranged in the first direction X and the second direction Y. Specifically, the first region 502C and the second region 504C are arranged in a checkerboard pattern. The patterns of the first region 502C and the second region 504C are not limited to the example shown in Figure 13.

[0076] The first region 502C and the second region 504C have different reflectivity with respect to the beam scanned by the scanning unit 100. For example, the second region 504C has a higher reflectivity than the first region 502C with respect to the beam scanned by the scanning unit 100. The second region 504C may also be a retroreflector.

[0077] The sensor device 10 obtains point cloud data by scanning the screen 500C. In the point cloud data obtained by scanning the screen 500C, a characteristic pattern appears due to the difference in reflectivity between the first region 502C and the second region 504C. Therefore, the sensor device 10 can use the point cloud data obtained by scanning the screen 500C to determine which region of the screen 500C the scanning range SA was projected onto. The measurement system 50C can measure the deviation of the scanning unit 100 from the reference position by comparing the scanning range SA projected onto the screen 500C by the scanning unit 100 when the scanning unit 100 is at the reference position with the scanning range SA projected onto the screen 500C when the scanning unit 100 is shifted from the reference position, based on the detection results of the sensor device 10.

[0078] Figure 14 is a diagram illustrating a fourth example of a measurement system 50D that measures the deviation of the scanning unit 100 from a reference position.

[0079] The measurement system 50D comprises a first screen 500Da and a second screen 500Db. The first screen 500Da and the second screen 500Db are aligned in the third direction Z. The first screen 500Da is located closer to the sensor device 10 in the third direction Z than the second screen 500Db.

[0080] In Figure 14, the scanning range SA shown by the solid line represents the scanning range projected onto the first screen 500Da by the scanning unit 100 when the scanning unit 100 is at its reference position. The scanning range SA shown by the dashed line represents the scanning range projected onto the first screen 500Da by the scanning unit 100 when the scanning unit 100 is deviated from its reference position. The first screen 500Da and the second screen 500Db are planes perpendicular to the third direction Z.

[0081] The first screen 500Da is provided with through holes 502Da. In at least a portion of the first screen 500Da, the through holes 502Da are regularly arranged in the first direction X and the second direction Y. Specifically, the through holes 502Da are arranged in a checkerboard pattern. The pattern of the through holes 502Da is not limited to the example shown in Figure 14.

[0082] The sensor device 10 obtains point cloud data by scanning the first screen 500Da. The beam directed toward the through-hole 502Da passes through the through-hole 502Da and is directed toward the second screen 500Db. Therefore, in the point cloud data obtained by scanning the first screen 500Da, the measurement data for the area of ​​the first screen 500Da where the through-hole 502Da is provided will be measurement data from a more distant area than the measurement data for the area of ​​the first screen 500Da where the through-hole 502Da is not provided. Therefore, the sensor device 10 can use the point cloud data obtained by scanning the first screen 500Da to determine which area of ​​the first screen 500Da the scanning range SA was projected onto. The measurement system 50D can measure the deviation of the scanning unit 100 from the reference position by comparing the scanning range SA projected onto the first screen 500Da by the scanning unit 100 when the scanning unit 100 is at the reference position with the scanning range SA projected onto the first screen 500Da when the scanning unit 100 is deviated from the reference position, based on the detection results of the sensor device 10.

[0083] The embodiments of the present invention have been described above with reference to the drawings, but these are merely examples of the present invention, and various other configurations can also be adopted.

[0084] This application claims priority based on Japanese Patent Application No. 2021-038050, filed on 10 March 2021, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0085] 10 Sensor device 12 cabinets 50A measurement system 50B measurement system 50C measurement system 50D measurement system 100 Scanning Unit 102 Reflective surface 102p pitch axis 102r Roll axis 102y yaw axis 200 Reflector 310 Measuring section 320 Correction Unit 400 Integrated Circuits Bus 402 404 Processor 406 memory 408 storage devices 410 Input / Output Interfaces 412 Network Interfaces 500A Screen 500B screen 500C Screen 500Da 1st Screen 500Db Second Screen 502C 1st area 502Da through hole 504C 2nd area 510A Imaging Unit 510B Imaging Unit AR1 First dashed arrow AR2 Second dashed arrow CR1 1st corner CR2 2nd corner CR3 3rd corner CR4 4th Corner LX 1st Virtual Line LXA First Virtual Line LY Second Virtual Line LYA Second Virtual Line S Spot SA scanning range X 1st direction Y Second direction Z 3rd direction

Claims

[Claim 1] Scanning unit and, A plurality of reflectors that reflect at least a portion of the beam irradiated onto the scanning range of the scanning unit, Equipped with, A sensor device in which the plurality of reflective portions are located at least four corners of the scanning range.

Images