KR102673029B1 - Lidar optical apparatus - Google Patents

Abstract

The present invention relates to a lidar optical device, which accurately detects the rotational speed and rotational position of a polygon mirror block (polygon mirror), a laser module assembly, and the polygon mirror block, and has a function for precise positioning of the laser module assembly. Detecting the rotational speed and rotational position of the polygonal mirror block at the end extending to the lower part of the rotation unit that is inserted into the inner hollow part of the polygonal mirror block and rotates the polygonal mirror block, and the rotation axis disposed to penetrate the center of the rotation unit. It includes a magnetic encoder for the laser module assembly and a laser adjuster that is coupled to the lower part of the laser module assembly and fixed to the lower case to perform an alignment function for position adjustment between the laser module assembly and the polygonal mirror block.

Description

LIDAR OPTICAL APPARATUS}

The present invention relates to a LiDAR optical device, and more specifically, to a LiDAR optical device that has a function for detecting the rotational speed and rotational position of a rotating polygon mirror block and for adjusting the position of the laser module assembly. It's about.

Recently, LIDAR (LIght Detection And Ranging) optical devices, which are laser radar devices, have been widely used to detect surrounding terrain or objects in cars or mobile robots.

This LiDAR optical device is a device that emits pulsed laser light into the atmosphere and uses reflected light from reflectors or scatterers in the atmosphere to measure distances, objects, or atmospheric phenomena. It calculates the time of the reflected light as a clock pulse and is usually used as a clock pulse. It has a resolution of 5m at a frequency of 30MHz and 1m at a frequency of 150MHz.

In this way, the LiDAR optical device irradiates laser light into the surrounding area and uses the time and intensity of the reflected light that is reflected by surrounding objects or terrain to measure the distance, speed, and shape of the object or surrounding objects or terrain. Scan precisely.

These LiDAR optical devices are widely applied in various fields such as sensors for detecting obstacles in front of robots and unmanned vehicles, radar guns for speed measurement, aerial geo-mapping devices, 3D ground surveys, and underwater scanning.

Accordingly, in LiDAR optical devices, it is necessary to detect conditions such as the rotational speed and rotational position of the mirror block that rotates at high speed in order to reflect the transmitted and received laser beam at the correct location and timing. In addition, there is a need to implement a high-resolution sensor to recognize rotation speed and rotation position even during high-speed rotation.

Additionally, in order to improve scanning performance, LiDAR optical devices require an alignment function for precise positioning between the laser module that receives and transmits the laser beam and the mirror block.

As a conventional technology to solve the above-mentioned requirements, a scanning lidar with a variable scanning vertical area is known in Korean Patent Publication No. 10-2017-0078031 (July 7, 2017).

The above background technology relates to a scanning lidar with a variable scanning vertical area, which controls the 360-degree rotation of a reflective mirror that reflects a pulse laser traveling toward a measurement target through a motor, and simultaneously uses a single or a few lasers, a receiver, and Through a structure in which the mirror rotates in the vertical direction, a scanning lidar with a variable scanning vertical area is provided that can secure safety based on the acquisition of 3D spatial information by scanning a wide area with an expanded vertical area. It lies in doing it.

However, the prior art discloses a configuration including a motor that rotates the reflective mirror 360 degrees and an angle adjuster that controls the reflective mirror to be tilted in the vertical direction, but the rotation speed of the mirror block operating at high speed There is a difference between recognizing the rotational position and implementing a sensor that can detect it and improving alignment performance for precise positioning between the laser module that receives and transmits the laser beam and the mirror block to improve scanning performance.

The present invention was derived to solve the problems of the prior art described above, and the purpose of the present invention is to recognize and detect the rotational speed and rotational position of a mirror block operating at high speed in a lidar optical device. In order to improve the sensor implementation function and scanning performance, the aim is to provide alignment performance for precise positioning between the laser module that receives and transmits the laser beam and the mirror block.

Another object of the present invention is to detect the position using the principle that the resistance value changes according to the flow of the magnetic field generated when the magnet rotates, and to adjust the position by combining it with the laser module assembly for precise position adjustment of the laser beam. The goal is to provide a high-performance lidar optical device with a simple structure made up of capable means.

A LIDAR (light detection and ranging radar) optical device according to an aspect of the present invention for solving the above technical problem includes a laser module assembly that performs laser transmission and reception operations, and a laser module assembly that transmits the laser on the front of the laser module assembly. It includes a polygonal mirror block that forms a reflection path for reception and a rotation unit that is inserted into an internal hollow portion of the polygon mirror block to rotate the polygon mirror block, and extends to the lower part of a rotation axis disposed to penetrate the center of the rotation unit. A magnetic encoder to detect the rotational speed and rotational position of the polygon mirror block at the end of the beam is coupled to the bottom of the laser module assembly and fixed to the lower case to perform an alignment function for position adjustment between the laser module assembly and the polygon mirror block. It may be configured to include an adjuster.

The magnetic encoder of the present invention has a cylindrical shape of a certain length and may be configured to rotate with a plurality of N poles and S poles facing each other with a certain gap on the inside.

In addition, the magnetic encoder of the present invention is coupled to an encoder PCB consisting of an electronic circuit for detecting resistance changes according to magnetic field intensity on the upper side, and the encoder PCB may be configured to include a Hall sensor.

In addition, the laser adjuster of the present invention is composed of a slider that can move the laser module assembly in the longitudinal direction and a rotating rotor that can adjust the rotational position of the laser module assembly to control rotation and longitudinal movement. You can.

Accordingly, the laser adjuster may be configured to have rail portions on both sides of the board frame so that the slider can adjust longitudinal movement along the rail portions.

According to the above-described lidar optical device, there is an effect of providing improvement in resolution and detection performance of the polygonal mirror block through a sensor configuration that can recognize and detect the rotational speed and rotational position of the mirror block that rotates at high speed.

In addition, the present invention provides alignment performance for precise positioning between the laser module and the mirror block, effectively controlling the reflection and scattering angles of the laser beam through the combined structure of the laser modules, mirror block, and rotation unit, and spatial data. It can provide the effect of maximizing spatial scanning performance that can secure .

Figure 1 is a perspective view showing the appearance of a lidar optical device according to an embodiment of the present invention.
Figure 2 is a perspective view showing the lidar optical device of Figure 1 with the external case removed.
Figure 3 is a plan view of the lidar optical device of Figure 1 with the external case removed.
Figure 4 is a cross-sectional view schematically showing the mirror rotating portion in the BB cross-section of Figure 3.
Figure 5 is a perspective view showing the coupling relationship between the mirror rotating part and the encoder magnet in Figure 4.
Figure 6 is a perspective view showing the configuration of the N pole and S pole of the encoder magnet.
FIG. 7 is a cross-sectional view schematically showing the laser module taken along AA in FIG. 3.
FIG. 8 is a bottom view showing the laser adjuster combined with the laser module in FIG. 6.

Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

Therefore, the embodiments described in this specification and the configuration shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, and therefore, various equivalents that can replace them at the time of filing the present application It should be understood that variations and variations may exist.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 is a perspective view showing the appearance of a LiDAR optical device according to an embodiment of the present invention, Figure 2 is a perspective view showing the external case removed from the LiDAR optical device of Figure 1, and Figure 3 is a LiDAR optical device of Figure 1. This is a top view of the optical device with the external case removed.

The lidar optical device 100 according to this embodiment includes an upper case 110 and a lower case 130, as shown in FIGS. 1 to 3, and is disposed on at least one surface of the upper case 110. It is provided with a window 120 that transmits the internal laser beam to the outside and transmits the laser beam reflected from the outside to the inside.

In addition, the lidar optical device 100 includes a laser module assembly 10, a polygonal mirror block 20, and a rotation unit 30 installed on the lower case 130.

The laser module assembly 10 includes a first laser module and a second laser module. The first laser module and the second laser module are installed to radiate laser to different areas of the first mirrors disposed on the upper part of the polygonal mirror block 20. The first laser module and the second laser module are installed to emit laser light toward at least one mirror on the surface of the polygonal mirror block 20 while being parallel to each other or at an acute angle to each other when their emission points are aligned.

The first or second laser module includes at least one laser diode and at least one photo diode that emits a pulsed laser beam. Here, the laser diode corresponds to the laser transmitting module, and the photo diode corresponds to the laser receiving module.

The polygonal mirror block 20 includes a plurality of mirrors arranged in a radial direction on the outer surface of the mirror block body. The plurality of mirrors reflects the first laser beam of the first laser module and the second laser beam of the second laser module on the front surfaces of the first laser module and the second laser module to reflect the laser beam for signal transmission and signal reception. In charge. Each of the plurality of mirrors may be disposed in a structure attached or coated on each surface of the sides of the polygonal pillar shape.

In addition, as shown, when a plurality of mirrors includes one mirror, for example, second to eighth mirrors sequentially arranged in the order described in a counterclockwise direction from the first mirror, each of the first to eighth mirrors has a square plate shape, and the reflecting surfaces of each of the first to eighth mirrors have different inclination angles with respect to a vertical direction that is perpendicular to the horizon and passes through each of the first to eighth mirrors, and the first mirror The inclination angles of each reflective surface from to the eighth mirror are arranged to gradually decrease or increase in a counterclockwise direction centered on the rotation axis of the polygonal mirror block 20 by the rotation unit 30. In this configuration, the arrangement of the first to eighth mirrors is not limited to counterclockwise, and of course, they can be arranged clockwise.

Therefore, the polygonal mirror block 20 is not limited to having eight mirrors in the form of a square plate, but a plurality of mirrors attached to the flat surface of each outer side in the form of a polygonal pillar, such as a pentagonal pillar or a 20-gonal pillar. can be provided.

In the above description, the polygonal mirror block 20 on which a plurality of mirrors are installed may be referred to as a mirror block in the form of a polygonal pillar. This polygonal mirror block 20 has an internal hollow part and is installed to rotate by a rotation unit 30 that is inserted into the internal hollow part and coupled with a fastening means such as a screw, nut, or bolt. According to the above-described configuration, a lidar optical device can be constructed simply by rotating the polygonal mirror block 20 through the rotation unit 30, such as a single motor, so the parts of the device can be reduced and the structure can be simplified. .

The plurality of mirrors of the polygonal mirror block 20 may include 5 or more to 20 mirrors arranged to be inscribed or circumscribed in a circle corresponding to the longitudinal cross-section of the outer peripheral surface of the mirror block body, and 8 to 12 mirrors. It is desirable to have them.

At least one of the first mirrors or the second mirrors may have a flat, curved, or aspherical shape. The arrangement of the laser modules or the emission angle of the laser light can be adjusted depending on the shape of the reflecting surfaces of the first mirrors and the second mirrors.

As shown in FIGS. 5 to 7, the rotation unit 30 includes a support plate overlapping the bottom plate of the lower case 130 and a motor support portion 31 extending vertically upward from the support plate. The motor support portion 31 is configured to seat and support a rotation unit such as a motor or a rotation unit 30 in the internal hollow portion of the polygonal mirror block 20.

The rotation axis 32 protruding from the top of the rotation unit 30 is arranged to penetrate the center of the polygonal mirror block 20. At this time, a portion of the motor support portion 31 surrounds and supports the rotation unit 30, extends to the inner upper part of the polygonal mirror block 20, and is closely fixed to the mirror unit 20 by a fastening means. According to this configuration, the polygonal mirror block 20 is coupled to the rotation axis 32 of the rotation unit 30 and can rotate stably without substantial shaking.

Accordingly, in the present invention, in order to accurately detect the rotational speed and rotational position of the polygonal mirror block 20, a magnetic encoder 33 is constructed that rotates at the end where the rotation axis 32 of the rotation unit 30 extends downward.

Figure 4 is a cross-sectional view schematically showing the mirror rotating part in the B-B cross section of Figure 3, Figure 5 is a perspective view showing the coupling relationship between the mirror rotating part and the encoder magnet in Figure 4, and Figure 6 is the N and S poles of the encoder magnet. This is a perspective view showing the composition.

As shown, there is a circular magnetic encoder 33 in the form of a cylinder with a certain length at the lower end of the rotation axis 32 extending from the inside of the polygonal mirror block 20, and consisting of a certain number of N and S poles on the inside. Position it.

In addition, an encoder PCB (35) consisting of an electronic circuit for detecting resistance changes according to magnetic field intensity is coupled to the upper side of the magnetic encoder (33), and the encoder PCB (35) includes a Hall sensor (34). It is done. The Hall sensor 34 is a magnetic resistance sensor.

The magnetic encoder 33 is a device that detects the position using the principle that the resistance value of the Hall sensor 34 changes according to the flow of the magnetic field generated when the magnet rotates.

The Hall sensor 34 is a sensor using the magnetoresistance effect and utilizes the property that the resistance value of an alloy thin film mainly composed of a ferromagnetic metal changes depending on the intensity of an external magnetic field.

The resistance change that occurs at this time can be obtained as a sinusoidal signal such as a sin signal and a cos signal using the encoder PCB (35), which can be obtained using trigonometry, table compensation, and ATO (Angle Tracking Observe). The rotation speed and direction can be detected by applying the same method.

In addition, in order to improve the resolution and detection performance of the polygonal mirror block 20 that requires high-speed rotation, the magnetic encoder 33 of the present invention is configured to have multiple N and S poles that face each other with a certain gap (GAP). do.

Additionally, since the output signal includes errors caused by the Hall sensor 34 itself and an external magnetic field, a process for compensating for these may be added.

FIG. 7 is a cross-sectional view schematically showing the laser module along the line A-A in FIG. 3, and FIG. 8 is a bottom view showing the laser adjuster combined with the laser module in FIG. 6.

As shown, in the present invention, in order to perform an alignment function for positioning the laser module assembly 10 and the polygon mirror block 20, a laser adjuster 40 board is additionally installed in the laser module assembly 10. It is coupled to the lower side of and is coupled to the lower case 130 to be fixed.

The laser module assembly 10 is configured to include first and second laser transmitting modules that transmit a laser beam and first and second laser receiving modules that receive the laser beam reflected from the lidar optical device, thereby performing scanning. You can extend the range or improve scanning speed.

Accordingly, it is necessary to precisely adjust the position of the laser module assembly 10 in order to scan the laser beam with the polygonal mirror block 20, and for this purpose, a laser adjuster is combined with the laser module assembly 10 to adjust the position. It constitutes (40).

The laser adjuster 40 consists of a slider 41 that can move the laser module assembly 10 in the longitudinal direction and a rotating rotor 42 that can adjust the rotational position of the laser module assembly 10. In order to adjust the longitudinal position of the laser adjuster 40, a rail portion 43 can be configured to be connected to the slider on the inside of the frame. Accordingly, the slider 41 can be controlled to move in the longitudinal direction along the rail portion 43.

Therefore, the laser adjuster 40 is coupled to the rotating rotor 42 at the lower center of the laser module assembly 10, and the rotating rotor 42 is coupled to the slider 41 on the same plane. Both sides are connected to the rail portion 43, allowing the laser module assembly 10 as a whole to provide precise rotation and longitudinal movement.

In this way, the lidar optical device 100 according to the present embodiment changes the reflection angle of the laser by rotating the polygonal mirror block 20 having a plurality of mirrors with gradually increasing or decreasing inclination angles to form one horizontal While transmitting and receiving laser beams on the scanning line corresponding to the line, the scanning angle and resolution can be changed by using multiple laser transmitting modules with different laser beam emission positions or laser beam emission angles, and the desired resolution can be effectively achieved. In order to achieve this, status recognition through a magnetic encoder (33) to detect the rotation speed and rotation position of the polygon mirror block (20) and position adjustment between the laser module assembly (10) and the polygon mirror block (20) are performed. This can be achieved by performing an alignment function through the laser adjuster 40.

On the other hand, although the control unit was not specifically mentioned in the above-described embodiment, the LiDAR optical device according to this embodiment or the LiDAR device 100 including the same may further include a control unit. In that case, the control unit controls the on-off operation or rotation speed of the rotation unit 30, such as a motor, or controls the transmission and reception operations of the laser module assembly 10, and transmits the received signal to an external device. It can be implemented. In that case, the control unit performs a control operation by synchronizing the laser beam transmission timing of the laser transmission module and the rotational position of the mirror block 20 to a preset position and timing.

The above-mentioned control unit may be implemented with at least one device selected from a logic circuit, programming logic controller, microcomputer, microprocessor, etc., and may include a communication module or be coupled to a communication module. The communication module communicates with external devices through intranet, Internet, vehicle network, etc., and can transmit signals or data related to the target detected through laser scanning or the distance to the target to the external device. This control unit may be mounted within the case of the laser module assembly 10, but is not limited thereto.

Meanwhile, although not shown in the drawing, the LiDAR device 100 may be provided with wiring, an adapter, or a power supply means for power supply. The power supply means may be provided with an internal power source or a rechargeable power supply, in which case the LiDAR device may be implemented to be used as a detachable device.

Using the lidar device of the present invention described above, the laser beam emitted from the laser module can be effectively reflected and emitted to the desired target range, and the laser beam reflected from the outside can be effectively received to detect the target by the laser beam. Target measurement can be performed effectively. In other words, the rotating mirror block effectively adjusts the angle of incidence and reflection of the laser beam emitted through the window from the inside of the outer case through the mirrors on the surface of the mirror block, and the laser modules that rotate at a certain angle adjust the mirrors of the mirror block to each other. It is possible to effectively perform laser scanning operations using different areas.

According to the above-described configuration, it is possible to maximize spatial scanning performance to secure spatial data while effectively controlling the reflection and scattering angles of the laser beam by the combined structure of the laser modules, mirror block, and rotation unit in the LiDAR device. There is an advantage.

It is natural that the present invention can be modified in various ways other than the above-described embodiments. The LiDAR device of the present invention can generally be applied to vehicles, but the present invention is not limited to this. In other words, the lidar optical device according to the present invention and the lidar device equipped with the same can be applied to movable objects such as robots, ships, helicopters, and drones as well as vehicles, and can also be applied to buildings, pillars, towers, etc., where movement is restricted. It can also be applied to fixtures without limitation.

As described above, preferred embodiments of the present invention have been described in the detailed description of the present invention, but those skilled in the art will understand the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. It will be understood that various modifications and changes can be made to the present invention.

100: Lidar optical device 110: upper case
120: Window 130: Lower case
10: Laser module assembly 20: Polygon mirror block
30: rotation unit 31: motor support
32: rotation axis 33: magnetic encoder
43: Hall sensor 35: Encoder PCB
40: Laser adjuster 41: Slider
42: rotating rotor 43: rail part

Claims (5)

As a LIDAR (light detection and ranging radar) optical device,
A laser module assembly that performs laser emission and reception operations,
A polygonal mirror block forming a reflection path for transmitting and receiving the laser on the front of the laser module assembly,
A rotation unit inserted into the inner hollow portion of the polygon mirror block to rotate the polygon mirror block,
A magnetic encoder for detecting the rotation speed and rotation position of the polygonal mirror block at the end extending below the rotation axis disposed to penetrate the center of the rotation unit, and
A laser adjuster is coupled to the lower part of the laser module assembly and fixed to the lower case to perform an alignment function for position adjustment between the laser module assembly and the polygonal mirror block,
The polygonal mirror block is,
Each includes first to eighth mirrors in the form of a square plate,
The inclination angles of each reflective surface of the first to eighth mirrors are,
The first to eighth mirrors are arranged to gradually become smaller or larger in a counterclockwise direction about a rotation axis in a vertical direction,
The magnetic encoder is,
It has a cylindrical shape of a certain length and rotates with a plurality of N and S poles facing each other with a certain gap on the inside, and an encoder PCB consisting of an electronic circuit to detect resistance changes according to magnetic field intensity is attached to the upper side. The encoder PCB includes a Hall sensor,
The laser adjuster is,
It consists of a slider that can move the laser module assembly in the longitudinal direction and a rotating rotor that can adjust the rotational position of the laser module assembly, controlling rotation and movement in the longitudinal direction, and forming rail sections on both sides of the board frame. A lidar optical device, characterized in that the slider is configured to adjust longitudinal movement along the rail portion.
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