CN209842062U - Laser radar and vehicle - Google Patents
Laser radar and vehicle Download PDFInfo
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- CN209842062U CN209842062U CN201822012129.0U CN201822012129U CN209842062U CN 209842062 U CN209842062 U CN 209842062U CN 201822012129 U CN201822012129 U CN 201822012129U CN 209842062 U CN209842062 U CN 209842062U
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- galvanometer
- light
- laser
- emitted light
- lidar
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Abstract
The utility model provides a laser radar. The laser emits emission light that produces reflected light at an object in the environment; a detector detects the reflected light, thereby determining the distance of the object; a galvanometer reflects the emitted light to the object; a first driver drives the portion of the galvanometer to rotate about a first axis such that the emitted light scans in a first direction; the second driver drives the entirety of the galvanometer to rotate about a second axis such that the emitted light is scanned in a second direction different from the first direction. Based on the technical scheme, the laser radar scans the emitted light of the same laser by using a single vibrating mirror, and compared with a multi-line radar in the prior art, the laser radar has the advantages that the number of lasers is obviously reduced, the size is smaller, and the cost is lower. Additionally, the utility model provides a vehicle including this kind of lidar.
Description
Technical Field
The present application relates to a lidar, and in particular to a lidar having a one-dimensional mechanical galvanometer, and a vehicle incorporating such a lidar.
Background
The vehicle may be configured to operate in an autonomous mode, wherein the vehicle navigates through environmental awareness with little or no driver intervention. Such autonomous vehicles may include one or more sensors, such as lidar, configured to detect environmental information about the vehicle surroundings.
The laser radar has a laser and a detector, the detector can detect laser light emitted by the laser and reflected by a reflecting object, and the distance to the reflecting object can be determined by measuring the flight time of the laser light. By scanning a region rapidly and repeatedly with a lidar, continuous real-time information of the distances of all reflecting objects in the region can be obtained. In combination with the distance, laser orientation and measurement time, "point cloud" data reflecting the topography, position and motion of various reflective objects may be generated, and by analyzing the "point cloud" data, autonomous operation of the vehicle may be assisted or achieved.
The prior art provides lidar in a variety of configurations. For example, the solid-state laser radar scans laser by using an MEMS two-dimensional galvanometer, which has the advantages of compact structure, fast scanning speed, etc., but is limited by the limitation of semiconductor process, and the cost of the MEMS galvanometer is very high, which limits the application of the solid-state laser radar. The multi-line laser radar adopts a plurality of lasers which are arranged in a line in the vertical direction, and realizes scanning in the horizontal direction by rotating the plurality of lasers through the rotating structure, so that the assembly process is complex, the cost is high, the problems of large volume, limited wire harness and the like are solved, and the performance of the multi-line laser radar is difficult to meet the increasing requirements.
Therefore, in practice, it is desirable to provide a laser radar with a novel structure which has low cost, small volume and high performance.
Disclosure of Invention
The utility model discloses aim at overcoming prior art's laser radar's defect, provide a take into account brand-new laser radar of low cost, little volume, high performance to and vehicle including this laser radar.
In a first aspect of the present invention, there is provided a laser radar, including: a laser that emits emission light that generates reflected light at an object in an environment; a detector that detects the reflected light, thereby determining a distance of the object; a galvanometer that reflects the emitted light to the object; a first driver that drives the portion of the galvanometer to rotate about a first axis such that the emitted light scans in a first direction; and a second driver that drives the entirety of the galvanometer to rotate about a second axis such that the emitted light is scanned in a second direction different from the first direction. Based on the technical scheme, the laser radar scans the emitted light of the same laser by using a single vibrating mirror, and compared with a multi-line radar in the prior art, the laser radar has the advantages that the number of the lasers is obviously reduced, the size is obviously smaller, and the cost of the laser radar is reduced.
Optionally, the first axis is disposed in a plane of the galvanometer, the second axis passes through the plane of the galvanometer at an acute angle, and the first axis is perpendicular to the second axis. Based on this technical scheme, the utility model discloses a mirror that shakes is the one-dimensional mirror that shakes, compares in the two-dimensional mirror that shakes among the prior art, can set up first driver and second driver relatively independently to the configuration and the maintenance degree of difficulty have been reduced.
Optionally, the galvanometer is fixed to the galvanometer support, and the second driver is coupled to the galvanometer support and drives it to rotate about the second axis. Based on this technical scheme, the second driver couples to the mirror support that shakes, utilizes the whole lidar of revolution mechanic rotation among the prior art, can show volume and the weight that reduces revolution mechanic, reduces the energy consumption of second driver to can improve its control accuracy.
Optionally, the galvanometer comprises a frame portion, a vibrating portion, and a connecting portion connecting the frame portion and the vibrating portion; wherein the frame portion is fixed to the galvanometer bracket, the first driver drives the vibrating portion to rotate relative to the frame portion about the first axis, and the bent portion of the connecting portion extends inward between the frame portion and the vibrating portion. Based on this technical scheme, the utility model discloses a mirror that shakes is the mechanical type mirror that shakes in fact, can be formed by the sheet metal processing of titanium alloy for example, for the MEMS mirror that shakes based on obtaining by semiconductor technology, this mechanical type mirror processing that shakes is easy, low cost.
Alternatively, the first driver is an electromagnet fixed to the galvanometer holder, the magnet being disposed on the vibrating section; alternating current is introduced into the electromagnet, the vibration part is driven to rotate up and down in a reciprocating mode relative to the plane of the galvanometer at a first frequency, and emergent light is enabled to scan up and down between a positive first angle and a negative first angle relative to the horizontal plane. Based on the technical scheme, the galvanometer does not bear current or pass through a coil of the current, and the galvanometer is not influenced by joule heat, so that the galvanometer has a stable structure and reliable scanning performance.
Optionally, the second driver is a stepper motor, an output shaft of which is coupled to the galvanometer holder; and driving the stepping motor by alternating current, and driving the galvanometer bracket to rotate around an output shaft of the stepping motor in a left-right reciprocating manner at a second frequency, so that the emergent light scans left and right between a positive second angle and a negative second angle relative to the vertical surface. Based on the technical scheme, the stepping motor is small in size, high in control precision and suitable for obtaining the laser radar with small size and high performance.
Alternatively, the first frequency is a resonance frequency of the vibrating portion, and the first frequency is greater than 100 times the second frequency. Based on this technical scheme, the vibration portion vibrates under resonant frequency, can reduce the energy consumption of first driver. Moreover, the first frequency is obviously higher than the second frequency, so that compact scanning lines can be obtained in the horizontal direction, and the detection precision is improved. For example, the first frequency may be 600Hz and the second frequency may be 5Hz, whereby 120 scan lines may be formed when the outgoing light is scanned once from left to right. Those skilled in the art can set other different scanning frequencies based on the teachings of the present invention, which all fall within the scope of the present invention.
Optionally, the first measuring module includes a light source and a linear detector, the emitted light of the light source is reflected to the linear detector via a vibrating portion of the galvanometer, the light source and the linear detector are mounted on the galvanometer holder, and a scanning angle of the emitted light in the first direction is measured by detecting a position where the emitted light is irradiated on the linear detector. Based on the technical scheme, the scanning angle of the emitted light in the first direction can be measured in real time without interference.
Optionally, the second measuring module includes an encoder fixed with respect to the stepping motor and a code wheel mounted on the galvanometer holder, and a scanning angle of the emitted light in the second direction is measured by detecting a position of the code wheel with respect to the encoder. Based on the technical scheme, the scanning angle of the emitted light in the second direction can be measured in real time without interference.
Optionally, the galvanometer reflects the reflected light to a detector. Based on this technical scheme, the light path of transmitted light and reflected light at least partially coincide, can improve the detection precision from this to reduce lidar's volume.
Optionally, a first mirror is disposed between the galvanometer and the laser to change the direction of transmission of the emitted light; the third reflector is arranged between the galvanometer and the detector to reflect the transmission direction of the reflected light. Based on the technical scheme, the light path can be folded by utilizing the reflecting mirror, and the volume of the optical structure is obviously reduced.
Optionally, the second mirror is disposed between the galvanometer and the first mirror, and between the galvanometer and the third mirror; the transmissive portion of the second mirror transmits the emitted light without changing a transmission direction of the emitted light, and the reflective portion of the second mirror reflects the reflected light to change a transmission direction of the reflected light. Based on the technical scheme, the coaxial light path design can be realized by utilizing the second reflector, the volume of the optical structure is further reduced, and the detection precision is improved.
Optionally, the lidar comprises a first laser and a second laser arranged adjacently, the scanning trajectory of the emitted light of the first laser and the scanning trajectory of the emitted light of the second laser being partially staggered. Based on the technical scheme, the number of the scanning lines can be encrypted, and the detection precision of the laser radar is improved.
Optionally, the lidar comprises a housing defining a closed interior chamber, housing the laser, the detector, the galvanometer, the first driver and the second driver; also, a window of the housing allows the emitted light and the reflected light to pass therethrough. Based on the technical scheme, the shell protects the internal components of the laser radar from being influenced by the external environment, prevents external optics from adversely influencing the operation of the laser radar, and provides an attractive plug-in.
In a second aspect of the invention, there is provided a vehicle comprising a lidar as described above which scans an environment and generates environmental data; the vehicle further includes a controller configured to: receiving environmental data from a lidar; determining information of an object in an environment based on the environment data, the information indicating at least one of: the type, topography, position or state of motion of the object; and controlling the starting, stopping, steering, speed changing or sending signals of the vehicle based on the information. Based on this solution, the vehicle can travel autonomously with little or no driver intervention.
Other aspects, embodiments, and implementations will become apparent to those of ordinary skill in the art upon reading the following detailed description and by referring appropriately to the accompanying drawings.
Drawings
Fig. 1 shows a block diagram of a lidar according to the present invention;
fig. 2 shows a perspective view of a lidar according to the present invention;
fig. 3 shows a perspective view of the optical path structure of the laser radar according to the present invention;
fig. 4 shows a perspective view of a scanning structure of a lidar in accordance with the present invention;
fig. 5 shows a rear perspective view of a galvanometer and an electromagnet of a lidar in accordance with the present disclosure;
fig. 6 shows a perspective view of a galvanometer and a position measuring device of a lidar in accordance with the present invention;
fig. 7 shows a perspective view of a lidar according to the present invention and a laser projection surface produced thereby.
Reference numerals:
1 laser 73 linear detector
2 detector 8 second driver
3 galvanometer 81 stepping motor
31 second measuring module of vibration part 9
32 connecting part 91 code disc
321 main beam 92 encoder
322 first secondary beam X vibration axis
324 second auxiliary beam Y rotating shaft
33 frame portion L1 emits light
331 first half L2 reflects light
332 second half P0 Main Circuit Board
4 optical structure P1 laser circuit board
41 first mirror P2 detector circuit board
42 first lens P3 first measurement circuit board
43 second mirror P4 second measuring Circuit Board
431 slit H0 main support
44 lens H1 first optical mount
45 third mirror H2 second optical mount
5 scanning structure H3 galvanometer support
6 first driver H4 mounting plate
61 electromagnet W casing
62 magnet W1 upper case
63 reflection groove W2 lower casing
7 first measuring module O window
71 light source B substrate equipment
72 steering mirror
Detailed Description
The invention is described below with reference to various embodiments with reference to the accompanying drawings. While this invention is described in terms of the best mode for achieving this invention's objectives, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the invention.
SUMMARY
Fig. 1 shows a block diagram of a radar according to the invention. The radar includes a laser 1 and a detector 2, the laser 1 emitting laser light continuously in the form of pulses at a specific frequency (e.g., 125kHz) with a wavelength of, for example, 905 nm. The emitted light is projected at an object (e.g., a building, a pedestrian, a vehicle, a traffic sign, etc.) located at a distance and generates reflected light. The detector 2 may receive the reflected light. By measuring the time difference Δ t between the emission of the laser pulse and the reception of the reflected light pulse, the distance d of the object from the laser 1 is obtained as C Δ t/2(C is the speed of light).
The radar comprises a vibrating mirror 3, wherein the vibrating mirror 3 can receive the emitted light from the laser 1 and reflect the emitted light to project the emitted light into a space to be measured; on the other hand, the galvanometer 3 may receive reflected light from an object in the space to be measured, and reflect it to project to the detector 2. By using the galvanometer 3, a coaxial optical path design can be achieved, i.e. the optical paths of the emitted light and the reflected light substantially coincide in the external optical path portion from the galvanometer 3 to the space to be measured. In the internal optical path portion from the galvanometer 3 to the laser 1 and detector 2, suitable optical structures 4 may be designed to direct the emitted and reflected light to meet specific structural and optical requirements.
The radar further comprises a scanning structure 5 for scanning the emitted light in both vertical and horizontal directions, converting point-like projected light from the laser 1 into planar projected light, so that the object can be detected in a larger spatial range. As shown in fig. 1, the scanning structure 5 includes, in addition to the galvanometer 3, a first driver 6 and a second driver 8. The first driver 6 can drive the galvanometer 3 to reciprocate up and down in a certain angle range around a vibration axis X, and the vibration axis X extends along the horizontal direction, so that one-dimensional scanning light which scans up and down in the vertical direction can be generated; further, the second driver 8 can drive the galvanometer 3 to rotate in a left-right reciprocating manner within a certain angle range around the rotating shaft Y, and the rotating shaft Y extends along the vertical direction, so that the left-right scanning movement in the horizontal direction can be superposed on the vertical direction on the basis of the up-down scanning movement, and the one-dimensional scanning light is further converted into the two-dimensional scanning light.
The scanning structure 5 further comprises a first measuring module 7 and a second measuring module 9 for measuring the deflection angle of the galvanometer 3 in real time. During scanning, the first measuring module 7 measures the deflection angle α of the galvanometer 3 with respect to the axis of vibration Xi(ii) a The second measuring module 9 measures the deflection angle beta of the galvanometer 3 relative to the axis of rotation Yi. By combination of angles (alpha)i,βi) A particular orientation of the emitted beam of light emitted by the lidar at a time may be determined. As described above, at each orientation (α) by measurementi,βi) Time difference of emitted light and received light, respective orientations (α) can be obtainedi,βi) Distance d of lower objectiThereby, a point cloud (alpha) representing three-dimensional environment information within the field of view of the laser radar can be obtainedi,βi,di). A processor may receive the point cloud, analyze and process it to perform a specific function. For example, in the case of applying a laser radar to an unmanned vehicle, the onboard computer may receive and analyze point cloud data from the laser radar to obtain the conditions of objects around the vehicle, thereby generating a specific control strategy to control the vehicle to perform functions such as steering, speed changing, start and stop, and the like, thereby achieving intelligent driving without driver intervention.
An embodiment of the lidar according to the present invention is described in detail below with reference to fig. 2 to 7.
Optical structure
Lidar comprises an optical structure for guiding the emitted and reflected light inside the radar apparatus. Fig. 3 shows the main components of the optical structure, and for clarity, fig. 3 omits components other than the optical structure compared to the general view of fig. 2. The laser 1 is electrically connected to a laser circuit board P1, and the circuitry carried on the laser circuit board P1 is adapted to drive the laser 1. The probe 2 is electrically connected to a probe circuit board P2, and the circuitry carried on the probe circuit board P2 is adapted to receive and transmit the output signal from the probe 2. The laser circuit board P1 and the detector circuit board P2 are both disposed parallel to each other and are vertically terminated on the same side to a main circuit board P0, which may carry electrical components such as a processor, memory, I/O interface, etc. on the main circuit board P0. The main circuit board P0 may be electrically connected to the laser circuit board P1 and the detector circuit board P2, whereby the processor may control the laser 1 to pulse light and process the output signal from the detector 2 to generate and output point cloud data representing the three-dimensional environmental conditions.
For convenience of description, a coordinate system is defined herein with reference to the position of the circuit board P0, including a vertical direction V, a front-rear direction F, and a lateral direction T, which are perpendicular to each other. The circuit board P0 is arranged in a plane defined by the vertical direction V and the lateral direction T, and the laser circuit board P1 and the probe circuit board P2 extend forward in the front-rear direction F.
As shown in fig. 3, the laser 1 is arranged to emit emission light L1 forward. The first mirror 41 is arranged in front of the laser 1 at an angle of 45 degrees to the emitted light L1, whereby the first mirror 41 directs the emitted light L1 to be deflected by 90 degrees so that it travels upwards in the vertical direction V. The emitted light L1 is transmitted upward through the first lens 42, the second reflecting mirror 43 in order, and then reaches the reflecting surface at the vibrating portion 31 of the galvanometer 3. The second reflecting mirror 43 is provided with a through slit 431 allowing the emitted light L1 to pass through the second reflecting mirror 43 without being reflected. The first lens 42 is disposed between the first mirror 41 and the second mirror 43, and the optical axis of the first lens 42 passes through the slit 431, whereby the emitted light L1 can be condensed and deflected to accurately pass through the slit 431. The deflecting action of the first lens 42 can cancel out the deviation of the emitted light L1 due to the mounting error, thereby reducing the requirement for mounting accuracy and simplifying the mounting process.
The mirror 3 is arranged at an angle, for example at an angle of 45 degrees, to the emitted light L1, so as to guide the emitted light L1 substantially forward into the space to be measured. As will be described in detail later, the emitted light L1 will be scanned in two dimensions with vertical vibration and horizontal rotation of the galvanometer 3. The emitted light L1 is reflected by objects in the environment to produce reflected light L2. The reflected light L2 irradiated on the reflecting surface of the galvanometer 3 is deflected by a certain angle by the galvanometer 3 and irradiated on the reflecting surface (upper surface) of the second reflecting mirror 43 in a substantially vertically downward direction. The second reflecting mirror 43 is at an angle of 45 degrees to the vertical direction V, whereby the second reflecting mirror 43 can guide the reflected light L2 to be transmitted rearward. Since the slit 431 of the second reflecting mirror 43 has a small area, most of the reflected light L2 is reflected. The reflected light L2 travels backward through the second lens 44, the third mirror 45 in order to reach the detector 2. The third mirror 45 is disposed between the circuit boards P1 and P2 and is perpendicular to the second mirror 43, thereby directing the reflected light L2 to continue to deflect and be transmitted upward in the vertical direction V to the detector 2. The second lens 44 is disposed between the second mirror 43 and the third mirror 45, and the second lens 44 may converge the divergently reflected light L2 to the detector 2.
As described above, the first reflecting mirror 41, the first lens 42, the second reflecting mirror 43, the galvanometer 3, the second lens 44, and the third reflecting mirror 45 constitute an optical structure, which can advantageously realize a coaxial optical path and give consideration to the compactness of the structure. Specifically, in the optical path from the second reflecting mirror 43 to the external space via the galvanometer mirror 3, the emitted light L1 and the reflected light L2 are arranged substantially coaxially, which contributes to elimination of optical errors existing in the paraxial optical path, improvement of accuracy of laser ranging, and simplification of the structural design. In addition, the first mirror 41 folds the optical path of the emitted light L1 and the third mirror 45 folds the optical path of the reflected light L2, which can greatly reduce the footprint of the optical structure 4 and allow the laser 1 and the detector 2 to be arranged adjacent to each other for easy electrical connection to the same main circuit board P0.
In addition, referring to fig. 2 and 3 in combination, the first optical support H1 may be used to support the first reflector 41, the first lens 42, the second reflector 43, and the mounting board 11 for mounting the laser 1, and the first optical support H1 cooperates with the first reflector 41, the second reflector 43, and the mounting board 11 to form a hollow enclosure, which effectively reduces the loss of the emitted light L1. Similarly, the second optical bracket H2 can be used to support the second lens 44, the third reflector 45 and the probe circuit board P2 for mounting the probe 2, and the second optical bracket H2 cooperates with the second lens 44, the third reflector 45 and the circuit board P2 to form a hollow closed shell, which effectively reduces the loss of the reflected light L2.
The present invention may employ one or more lasers 1 and detectors 2. The embodiment of fig. 3 shows two lasers 1 and two detectors 2. Two lasers 1 are arranged side by side on the mounting board 11, and their emitted light L1 may form an acute angle in the forward direction. The two emitted lights L1 and their respective reflected lights L2 are transmitted through the above-mentioned optical structure 4, and the two reflected lights L2 finally reach two detectors 2 respectively disposed side by side on the detector circuit board P2. Since the emitted light L1 of the two lasers 1 forms an acute angle, the laser projection planes that they respectively scan will have overlapping portions. By setting the relationship between the acute angle and the horizontal scanning rate of the galvanometer 3, the point clouds generated by the two lasers 1 can be distributed in the overlapping part in a staggered manner, so that the encryption effect is achieved, and the point cloud density is improved. Note that the width of the slit 431 on the second reflecting mirror 43 is set to allow the two emitted lights L1 to pass through simultaneously. Although the illustrated embodiment shows two lasers and two detectors, in the embodiments not shown, three, four or other numbers of lasers and detectors may be used to achieve better encryption effect, and these embodiments not shown all fall into the scope of the present invention.
Scanning structure
Fig. 4 shows a scanning structure 5 of the lidar for scanning a point-like emitted light from the laser 1 into a two-dimensional projection surface, as best shown in fig. 7.
The scanning structure 5 comprises a galvanometer 3 machined from a sheet of metal, for example a titanium alloy. As shown in fig. 4, the galvanometer 3 includes a vibrating portion 31, a connecting portion 32, and a frame portion 33. The vibrating portion 31 is circular, and is connected at both ends of one diameter to the frame portion 33 via the connecting portions 32. The direction of said diameter defines the axis of vibration X. The frame portion 33 is symmetrical about the vibration axis X, and may be divided into a first half 331 and a second half 332 on both sides of the vibration axis X. The connecting portion 32 on each side of the vibrating portion 31 includes a main beam 321, a first sub beam 322, and a second sub beam 323. The main beam 321 extends along the vibration axis X and is linear; the first sub-beam 322 and the second sub-beam 323 extend substantially in a direction perpendicular to the vibration axis X and are zigzag-shaped. One end of the main beam 321 is connected to the circumference of the vibration part 31, and the other end is connected to one ends of the first and second sub-beams 322 and 323. The first secondary beam 322 and the second secondary beam 323 are symmetrical about the axis of vibration X, with their respective other ends, remote from the main beam 321, connected to a respective first 331 or second 332 half of the frame part 33. Thereby, the vibrating portion 31 can be reciprocally rotated (may be referred to as "vibration") within a certain angular range with respect to the frame portion 33 about the vibration axis X, supported by the connecting portion 32.
As shown in fig. 3, a through space is defined between the vibrating portion 31 and the frame portion 33, and each of the first sub-beam 322 and the second sub-beam 323 has a bent portion extending into the space. By adjusting parameters such as the length of the bending part, the width of the main beam 321, and the widths of the first sub-beam 322 and the second sub-beam 323, the vibration part 31 can be adjusted to have a suitable resonance frequency, such as 600Hz, and a suitable vibration angle range, such as 5 to 30 °, preferably 10 °. In addition, due to the arrangement of the bending part, the whole length of the connecting part 32 is extended, so that stress concentration at the intersection of the main beam 321, the first secondary beam 322 and the second secondary beam 323 is remarkably reduced, the fatigue performance of the galvanometer 3 is improved, and the service life is prolonged.
On the one hand, the vibrating portion 31 of the galvanometer 3 may be vibrated about a vibration axis X (shown in fig. 4) by the driving of the first driver 6, whereby the emitted light may be scanned in the vertical direction within a certain angle range, for example, within a range of 10 to 60 °, preferably 20 °. A mirror for reflecting the laser beam may be bonded to the vibrating portion 31, or one surface of the vibrating portion 31 may have a reflecting property. The first driver 6 may be an electromagnet 61 while a magnet 62 is provided on the back (the opposite side of the reflection surface) of the vibrating portion 31. When an alternating current is applied to the electromagnet 61, which generates a magnetic field with alternating directions, the magnet 62 receives alternating attractive or repulsive forces, thereby driving the vibrating portion 31 to vibrate about the vibration axis X. By setting the amplitude and frequency of the current in the electromagnet 61, it is possible to realize that the vibrating portion 31 vibrates just at its resonance frequency (e.g., 600Hz), thereby realizing vibration with less energy consumption.
Fig. 5 shows a rear perspective view of the galvanometer 3. Two cylindrical magnets 62 are symmetrically disposed at the back of the vibration part 31, and the mass of the magnets 62 and the distance from the center of the vibration part 31 can be adjusted to achieve resonance of the vibration part 31. The two electromagnets 61 are arranged opposite to each other for generating a symmetrical magnetic field. To induce stable vibration, the two magnets 62 are subjected to magnetic forces of opposite directions and equal magnitude at the same time. For this purpose, it is possible to provide two magnets 62 with opposite magnetic properties, and two electromagnets 61 with the same magnetic properties; alternatively, the two magnets 62 may be arranged to be of the same polarity and the two electromagnets 61 may be of opposite polarity.
On the other hand, the galvanometer 3 is rotatable as a whole about a rotation axis Y (as shown in fig. 4) by the driving of the second driver 8, whereby the emitted light can be scanned in the horizontal direction within an angle range, for example, within an angle range of 20 to 180 °, more preferably 40 to 90 °, more preferably 48 °. The second driver 8 may be a stepping motor 81, and by controlling the driving current, the rotation speed and the rotation direction of the stepping motor 81 can be accurately regulated. The stepping motor 81 is controlled to output reciprocating rotation within a certain angle range. As shown in fig. 4, the electromagnet 61 as the first driver 6 and the galvanometer 3 are mounted on a galvanometer holder H3. An output shaft of the stepping motor 81 is coupled to an upper end of the galvanometer holder H3, thereby driving the galvanometer holder H3 and the galvanometer 3 thereon to rotate together. As a result, the vibrating portion 31 of the galvanometer 3 also reciprocates around the rotation axis Y.
Therefore, the vibrating portion 31 of the galvanometer 3 rotates about the rotation axis Y while vibrating about the vibration axis X, and the vibration axis X and the rotation axis Y intersect perpendicularly at the center of the vibrating portion 31, as shown in fig. 4. In use, the vibration axis X may be arranged to extend in a horizontal direction parallel to the ground, so that the vibrating motion of the galvanometer 3 scans the laser in a vertical direction; meanwhile, the rotation axis Y may be set to extend in the vertical direction perpendicular to the ground, so that the laser is scanned in the horizontal direction by the rotational movement of the galvanometer 3, thereby obtaining two-dimensional scanning light.
As described above, in order to obtain three-dimensional point cloud data, it is necessary to measure the deflection angle α of the galvanometer 3 with respect to the vibration neutral position and the deflection angle β with respect to the rotation neutral position in real time. Fig. 6 shows a first measuring module 7 for measuring the angle α and a second measuring module 9 for measuring the angle β, wherein further components are omitted. The galvanometer 3 in fig. 6 is in a neutral position of non-vibrating and rotating with an angle a of zero and an angle β of zero.
The first measuring module 7 includes a light source 71 and a linear detector 73, which may be disposed on a first measuring circuit board P3, the first measuring circuit board P3 and the main circuit board P0 being electrically connected. The light source 71 emits a light beam forward, and the light beam is turned by a turning mirror 72 disposed at an angle of 45 degrees and then travels downward to the back of the vibration part 31. As shown in fig. 5, the rear surface of the vibration part 31 is provided with a linear reflection groove 63, and the two electromagnets 61 are separately provided to allow the light beam to reach the reflection groove 63. Thereby, the reflective groove 63 may reflect the light beam such that it propagates to the receiving area of the linear detector 73. The linear detector 73 may be a photodiode array with an elongated receiving area. In this configuration, when the galvanometer 3 vibrates, the angle between the reflection groove 63 and the light beam will change with the change of the vibration position of the galvanometer 3, and accordingly, the spot of the reflected light beam of the reflection groove 63 falling on the linear detector 73 will move up and down. The linear detector 73 can detect the position change of the light spot and then deduce the change of the angle α of the galvanometer 3. It should be noted that the first measurement circuit board P3 is fixed to the rear side of the galvanometer holder H3 (not shown in fig. 6), and the light source 71 and the steering mirror 72 are both mounted in the inner cavity of the galvanometer holder H3, so that the components of the first measurement module 7 will rotate together with the galvanometer holder H3 and the galvanometer 3 about the rotation axis Y. Thus, during the rotational movement of the galvanometer 3, the components of the first measuring module 7 are relatively stationary, so that the rotational movement of the galvanometer 3 does not disturb the measurement of the angle α.
The second measuring module 9 comprises a code wheel 91 and an encoder 92. The code wheel 91 is fixed to the upper surface of the galvanometer holder H3 (not shown in fig. 6, see fig. 2), and a plurality of code tracks uniformly distributed in the circumferential direction are provided on the code wheel 91. The encoder 92 is fixedly disposed with respect to the stepping motor 81 and is carried by a second measurement circuit board P4, and the second measurement circuit board P4 may be electrically connected to the main circuit board P0. As shown in FIG. 6, the encoder 92 and the code wheel 91 are disposed opposite to each other, and detect the presence of the facing code track, thereby calculating the rotation angle of the code wheel 91. Since the code wheel 91 and the galvanometer 3 on the galvanometer holder H3 rotate synchronously, the encoder 92 can detect the rotation angle beta of the galvanometer 3 around the rotation axis Y. Specifically, as shown in fig. 6, the code wheel 91 is a partial circular ring shape, and the extension angle thereof corresponds to the rotation angle range of the stepping motor 81. In addition, the code wheel 91 and the second measurement circuit board P4 are provided with through holes that allow the output shaft of the stepping motor 81 to pass through.
As described above, in the scanning structure 5 of the present invention, the galvanometer 3 is a one-dimensional mechanical galvanometer, and the galvanometer 3 vibrates under the driving of the electromagnet 61 and rotates under the driving of the stepping motor 81. Thus, scanning over a two-dimensional plane can be achieved with only a single laser 3, with a smaller number of lasers and a significantly lower cost and power consumption than in prior art multi-line radars. In addition, compare the MEMS mirror that shakes among the prior art, the utility model discloses a mechanical type shakes mirror and makes simply, low cost to have and show bigger optical reception area, can simplify optical structure and improve signal strength. Furthermore, compare the two-dimentional mirror that shakes among the prior art, the utility model discloses a mirror that shakes's axis of rotation Y does not set up in the mirror plane that shakes, but sets up along vertical direction V, and under this condition, lidar's horizontal direction scanning is more close to multi-thread radar's horizontal direction scanning, and the point cloud that obtains is the distribution on the horizontal direction, does not have the distortion, changes in the analysis and treatment point cloud, can show the detection precision that improves lidar.
Mounting structure
Referring back to the general perspective view of FIG. 2, the lidar includes a series of mounting structures for mounting various functional components. As shown, main stand H0 extends in a vertical direction, which is an inverted U-shaped frame configuration. The main circuit board P0 is fixed to the main stand H0 by bolts from the rear. The first bracket H1 is fixed to the main bracket H0 by bolts from below and extends forward for supporting the laser mounting board P1, the first mirror 41, the first lens 42, and the second mirror 43, as described above. The second bracket H2 is bolted over the first bracket H1 for supporting the probe mounting plate P1, the second lens 44 and the third mirror 45, as described above. Second stent H2 is located in the intermediate space of main stent H0 and is fixed to main stent H0 by bolts. Thus, main stent H0, first stent H1 and second stent H2 form a triangular stable connection. In addition, a mounting plate H4 is fixed to the main stand H0 by bolts from above, which extends forward perpendicular to the main stand H0, and the stepping motor 81 is mounted to the upper side of the mounting plate H4. The output shaft of the stepper motor passes through the mounting plate H4. In addition, a second measurement circuit board P4 may be mounted to the lower side of the mounting board H4. As shown in fig. 2, the main stand H0, the first stand H1, the second stand H2, and the mounting plate H4 may enclose a space in which the galvanometer stand H3 is disposed and connected to the output shaft of the stepping motor 81 at the upper end. The galvanometer holder H3 is configured to support a plurality of components such as the galvanometer 3, the electromagnet 61, the light source 71 of the first measuring module 7, the steering mirror 72 and the linear detector 73, and the code wheel 81 of the second measuring module 8, which are rotated as a whole by the driving of the stepping motor 81. The arrangement of the mounting structure as described above can satisfy both the requirements of structural stability and volume compactness.
Fig. 7 shows the external appearance of the lidar having a housing W for accommodating the internal structure of the lidar shown in fig. 2, which may be placed into a cavity of the housing W from the rear of the housing W. The casing W comprises an upper casing W1 and a lower casing W2 which can be detached, and radiating fins can be arranged on the upper casing W1 and the lower casing W2 for radiating heat of the laser radar. In addition, the front surface of the lower case W2 is provided with a window O allowing the laser light to pass therethrough without loss. The housing W can protect the laser radar from the external environment and provide a compact and aesthetically pleasing appearance.
Application example
The utility model discloses a laser radar can be arranged in the occasion that the multiple needs know the surrounding environment condition, including but not limited to fields such as unmanned vehicle, unmanned aerial vehicle, industry storage logistics guided vehicle, intelligent robot, satellite. As shown in fig. 7, a laser radar may be fixed to a base device B (e.g., a vehicle, an airplane, etc.), and the laser radar may project a two-dimensional laser projection surface forward. As described above, the laser projection plane is generated by the scanning motion of the laser light from a single laser in both the horizontal and vertical directions. The embodiment of the present invention provides a laser radar, wherein the scanning frequency of the laser radar in the horizontal direction can be 5Hz, the scanning frequency in the vertical direction can be 600Hz, and the emitting frequency of the laser can be 125 KHz. In addition, the horizontal scanning angle (field of view) of the laser radar can be +/-24 degrees, and the angular resolution can be 0.2 degrees; the vertical scan angle may be ± 10 °, and the angular resolution may be 0.2 °. Taking the base device B as a road vehicle as an example, when the two-dimensional laser projection surface shown contacts an object such as a pedestrian, a vehicle ahead, a traffic sign, a building, etc., the laser radar may generate point cloud data related to the object, and a processor integrated in the road vehicle may process the point cloud data to identify information of the type, shape, position, and movement of the object, and further generate a control signal according to the information, control the vehicle to perform corresponding operations such as start-stop, steering, speed change, etc., and/or send a signal to a passenger or a remote server. Thus, it is possible to realize driving assistance or autonomous driving using the laser radar.
While various examples and embodiments have been disclosed, other examples and embodiments will be apparent to those skilled in the art. The various disclosed examples and embodiments are intended to be illustrative, but not limiting, with the true scope and spirit being indicated by the following claims.
Claims (15)
1. A lidar, comprising:
a laser that emits emission light that generates reflected light at an object in an environment;
a detector that detects the reflected light, thereby determining a distance of the object;
a galvanometer that reflects the emitted light to the object;
a first driver that drives the portion of the galvanometer to rotate about a first axis such that the emitted light scans in a first direction; and
a second driver that drives the entirety of the galvanometer to rotate about a second axis such that the emitted light is scanned in a second direction different from the first direction.
2. The lidar of claim 1, wherein the first axis is disposed in a plane of the galvanometer and the second axis passes through the plane of the galvanometer at an acute angle, the first axis being perpendicular to the second axis.
3. The lidar of claim 1 or 2, wherein the galvanometer is fixed to a galvanometer holder, and wherein the second actuator is coupled to the galvanometer holder and drives the galvanometer holder to rotate about the second axis.
4. Lidar according to claim 3,
the galvanometer comprises a frame part, a vibrating part and a connecting part for connecting the frame part and the vibrating part;
wherein the frame portion is fixed to the galvanometer bracket, the first driver drives the vibrating portion to rotate relative to the frame portion about the first axis, and the bent portion of the connecting portion extends inward between the frame portion and the vibrating portion.
5. Lidar according to claim 4,
the first driver is an electromagnet fixed to the galvanometer holder, and the magnet is disposed on the vibrating part;
alternating current is introduced into the electromagnet, the vibration part is driven to rotate up and down in a reciprocating mode relative to the plane of the galvanometer at a first frequency, and emergent light is enabled to scan up and down between a positive first angle and a negative first angle relative to the horizontal plane.
6. Lidar according to claim 5,
the second driver is a stepping motor, and the output shaft of the second driver is coupled to the galvanometer bracket;
and driving the stepping motor by alternating current, and driving the galvanometer bracket to rotate around an output shaft of the stepping motor in a left-right reciprocating manner at a second frequency, so that the emergent light scans left and right between a positive second angle and a negative second angle relative to the vertical surface.
7. Lidar according to claim 6,
the first frequency is a resonance frequency of the vibrating portion, and the first frequency is greater than 100 times the second frequency.
8. Lidar according to claim 5,
the first measuring module comprises a light source and a linear detector, emitted light of the light source is reflected to the linear detector through a vibrating part of the galvanometer, the light source and the linear detector are installed on the galvanometer support, and the scanning angle of the emitted light in the first direction is measured by detecting the position of the emitted light irradiated on the linear detector.
9. Lidar according to claim 6,
the second measuring module comprises an encoder and a coded disc, the encoder is fixed relative to the stepping motor, the coded disc is installed on the galvanometer bracket, and the scanning angle of the emitted light in the second direction is measured by detecting the position of the coded disc relative to the encoder.
10. The lidar of claim 1, wherein the galvanometer reflects reflected light to a detector.
11. Lidar according to claim 10,
the first reflector is arranged between the vibrating mirror and the laser to change the transmission direction of the emitted light;
the third reflector is arranged between the galvanometer and the detector to reflect the transmission direction of the reflected light.
12. Lidar according to claim 11,
the second reflecting mirror is arranged between the vibrating mirror and the first reflecting mirror and between the vibrating mirror and the third reflecting mirror;
the transmissive portion of the second mirror transmits the emitted light without changing a transmission direction of the emitted light, and the reflective portion of the second mirror reflects the reflected light to change a transmission direction of the reflected light.
13. Lidar according to claim 1,
the laser radar comprises a first laser and a second laser which are adjacently arranged, and the scanning tracks of the emitting light of the first laser and the scanning tracks of the emitting light of the second laser are partially staggered.
14. Lidar according to claim 1,
the laser radar comprises a shell, wherein the shell defines a closed inner cavity and contains a laser, a detector, a galvanometer, a first driver and a second driver; also, a window of the housing allows the emitted light and the reflected light to pass therethrough.
15. A vehicle, characterized by comprising:
lidar according to any of claims 1 to 14, scanning an environment and generating environment data;
a controller configured to:
receiving environmental data from a lidar;
determining information of an object in an environment based on the environment data, the information indicating at least one of: the type, topography, position or state of motion of the object;
and controlling the starting, stopping, steering, speed changing or sending signals of the vehicle based on the information.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822012129.0U CN209842062U (en) | 2018-12-03 | 2018-12-03 | Laser radar and vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822012129.0U CN209842062U (en) | 2018-12-03 | 2018-12-03 | Laser radar and vehicle |
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| CN209842062U true CN209842062U (en) | 2019-12-24 |
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| CN201822012129.0U Expired - Fee Related CN209842062U (en) | 2018-12-03 | 2018-12-03 | Laser radar and vehicle |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113311409A (en) * | 2021-04-11 | 2021-08-27 | 桂林理工大学 | Method for controlling two-dimensional galvanometer scanning system based on Bresenham algorithm |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113311409A (en) * | 2021-04-11 | 2021-08-27 | 桂林理工大学 | Method for controlling two-dimensional galvanometer scanning system based on Bresenham algorithm |
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Granted publication date: 20191224 Termination date: 20211203 |