CN114791595A - Packet launch lidar - Google Patents

Abstract

The invention discloses a group-emission laser radar. A laser radar according to an embodiment of the present invention includes: a plurality of transmitters for emitting laser light; a plurality of receivers that receive laser light reflected outside the laser radar after being emitted from the transmitter; the emitters are divided into a plurality of emitter groups, the number of the emitters in each emitter group is the same, the emitters in one emitter group are arranged adjacently, one emitter in each emitter group emits laser at a time, and the emitters in the same position of each emitter group in the emitters simultaneously emit laser; the number of the receivers is the same as that of the transmitter groups, and one receiver receives laser light which is respectively emitted by the transmitters in one transmitter group and then reflected outside the laser radar.

Description

Packet launch lidar

technical field

The present invention relates to a laser radar, in particular to a laser radar capable of transmitting in groups.

Background technique

In the field of autonomous driving and autonomous walking robots, devices such as Lidar (LIDAR) can be used to detect surrounding objects. Lidar can transmit a laser beam to the surrounding three-dimensional space as a detection signal, and make the laser beam irradiate the object in the surrounding space and be reflected to become an echo signal and return, and the lidar will receive the echo signal and the transmitted detection signal Comparisons are made to obtain relevant information about surrounding objects such as distance, speed, etc.

The above-mentioned lidar includes a transmitting module and a receiving module. The transmitting module generates and emits a laser beam, and the laser beam that hits the surrounding objects and is reflected back is received by the receiving module. Since the speed of light is known, the distance of surrounding objects relative to the lidar can be measured by the travel time of the laser.

Regarding the emission of lasers, existing lidars have achieved 32-line or 64-line laser output. In this multi-line lidar, a structure in which a plurality of edge-emitting lasers (EELs) are provided in the transmitting module is adopted. The laser light of the edge-emitting laser is emitted perpendicular to the top surface, ie, the laser light is emitted from the side of the edge-emitting laser. Therefore, in the prior art, a plurality of edge-emitting lasers are respectively disposed on the edges of a plurality of substrates, and then a plurality of substrates are stacked to realize a multi-line laser radar.

However, in the above structure, each laser emits light independently, and a corresponding number of receivers are required, and a corresponding number of driving circuits for driving the lasers and receiving circuits for processing data of the receivers are required. A large number of these components in a lidar causes the cost of the lidar to go up. Therefore, there is a need for a lidar that can reduce costs.

SUMMARY OF THE INVENTION

The present invention provides a group-transmitting laser radar that can reduce costs.

A lidar according to an embodiment of the present invention includes: a plurality of transmitters for emitting laser light; a plurality of receivers for receiving the laser light emitted from the transmitters and reflected outside the lidar; wherein the plurality of transmitters are divided into Multiple transmitter groups, the number of transmitters in each transmitter group is the same, the transmitters in one transmitter group are arranged adjacently, one transmitter in each transmitter group emits laser light at a time, and multiple transmitters The transmitters in the same position of each transmitter group emit laser light at the same time; among them, the number of receivers is the same as the number of transmitter groups, and one receiver receives the laser light from the transmitters in one transmitter group respectively. The laser is reflected from the outside of the radar.

Also, the plurality of transmitters may be arranged in a line array form; the plurality of receivers may be arranged in a line array form.

In addition, it can also include: a plurality of driving circuits for driving the transmitter to emit laser light, wherein the number of driving circuits is the same as the number of transmitters included in each transmitter group, and each driving circuit simultaneously drives and emits laser light at the same time of multiple transmitters.

In addition, it can also include: a plurality of driving circuits for driving the transmitter to emit laser light, wherein the driving circuit is connected to all transmitters in one transmitter group, and drives one transmitter in one transmitter group each time, The number of driver circuits is the same as the number of transmitter banks.

Also, a plurality of the transmitters may be distributed on a circumference; and a plurality of the receivers may be distributed on a circumference.

In addition, it may also include: a plurality of driving circuits for driving the transmitter to emit laser light, and a plurality of the driving circuits are arranged inside the circumference where the transmitter is located.

And, a plurality of the driving circuits are arranged in a point-symmetric manner.

A lidar according to another embodiment of the present invention includes: a plurality of transmitters for emitting laser light and distributed over a circumference; a plurality of receivers for receiving the laser light emitted from the transmitters and reflected outside the lidar, and Distributed in a circle; a plurality of driving circuits are used to drive the transmitters to emit laser light, wherein the transmitters are divided into a plurality of transmitter groups, the number of transmitters in each transmitter group is the same, and one transmitter group The transmitters are arranged adjacently, one transmitter in each transmitter group emits laser light at a time, and the transmitters located in the same position of each transmitter group among the multiple transmitters emit laser light simultaneously; The number is the same as the number of transmitter groups, one receiver receives the laser light respectively emitted from the transmitters in one transmitter group and then reflected on the outside of the lidar, and the number of driving circuits is the same as the number of transmitters included in each transmitter group. The number is the same, and each driver circuit simultaneously drives multiple transmitters that emit laser light at the same time.

According to an embodiment of the present invention, the following effects can be achieved: 1) the number of driving circuits and receiving circuits (such as transimpedance amplifiers, TDC (time-to-digital converters)) can be reduced; 2) the cost is relatively low and can be applied It is suitable for products with low total price and low requirements on measurement accuracy, such as cleaning robots; 3) Compared with each emitter alone, it can reduce the time required for all emitters to emit light once.

The effects of the present invention are not limited to the above-described effects, and those skilled in the art can derive effects not described above from the following description.

Description of drawings

FIG. 1 is a schematic diagram illustrating a lidar according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a driving circuit according to an embodiment.

FIG. 3 is a schematic diagram illustrating a driving circuit according to another embodiment.

FIG. 4 is a schematic diagram illustrating a lidar according to a second embodiment of the present invention.

5 is a schematic diagram showing a driving circuit of a lidar according to a second embodiment of the present invention.

Detailed ways

The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments disclosed below are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the following embodiments, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

And, in the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship of the drawings, And it is only a simplified description for the convenience of describing the present invention, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

FIG. 1 is a schematic diagram illustrating a lidar according to a first embodiment of the present invention.

As shown in FIG. 1, a lidar according to a first embodiment of the present invention includes a transmitter array and a receiver array. The transmitters in the transmitter array can emit laser light that bounces off objects outside the lidar and returns to the receivers in the receiver array. Thus, the distance between the surrounding objects and the lidar can be measured by the time-of-flight method (TOF).

The number of transmitters in the transmitter array is not limited, for example, the transmitter array may include 64 or 128 transmitters. The situation in which the number of transmitters in the transmitter array is a multiple of six is shown in FIG. 1 .

The emitters in the emitter array can be edge emitting lasers (EELs) or vertical cavity surface emitting lasers (VCSELs). Among them, the laser of the edge-emitting laser (EEL) is emitted parallel to the substrate, and the laser of the vertical cavity surface-emitting laser (VCSEL) is emitted perpendicular to the substrate. In the present invention, as long as the transmitter can emit laser light to the outside, its specific type is not limited.

The receivers in the receiver array can be avalanche photodiodes (APDs) or single photon avalanche diodes (SPADs). The type of the receiver is not limited thereto, and the specific type of the receiver can be appropriately selected by those skilled in the art within the range of well-known photoelectric sensors.

Hereinafter, the structure of the laser radar according to the first embodiment of the present invention will be described in more detail.

As shown in FIG. 1, the portion of the transmitter array shown with a box represents the entire transmitter array, and the portion of the block with a small circle is a single transmitter. Also, the part represented by a large square in the receiver array represents the entire receiver array, and the part represented by a small square in the large square is a single receiver. Wherein, the transmitter array and the receiver array may be a transmitter line array and a receiver line array, respectively.

As shown in Figure 1, multiple transmitters in a transmitter array can be grouped. Figure 1 shows a situation where 6 transmitters are in a group, the number of transmitters in each group of transmitters is not limited, for example, it can be 8 transmitters in a group, preferably, in each group of transmitters The same number of transmitters are included, and transmitters in each transmitter group are arranged adjacently without mixing with transmitters in other transmitter groups. Further, the number of groups of transmitters is not limited, and the number of groups of transmitters can be increased according to actual needs.

By dividing the emitter array into multiple emitter groups, it is possible to have 1 emitter in each group lasing simultaneously. For example, as shown in Figure 1, assuming there are N groups of transmitters, and each group of transmitters has 6 transmitters, the No. 1 transmitter in each group of transmitters can be made to emit light at the same time, so that N transmitters can be made to emit light at the same time laser. Next, emitter 2 in each group of emitters can be made to emit light at the same time, until emitter 6 in each group of emitters emits light simultaneously. Thus, all emitters in the emitter array can be lased by 6 firings.

Therefore, if there are N groups of emitters, and each group includes M emitters, the first emitter in the N groups of emitters can be made to emit light at the same time, and then the second emitter in the N groups of emitters can be made to emit light at the same time. Simultaneously emit light until the Mth emitter in the N groups of emitters emits light simultaneously. Therefore, by emitting light M times, N emitters can be made to emit light each time, so that all M×N emitters can emit light.

By the emission control as described above, the time required to make all the emitters emit light once can be reduced. Also, the number of driving circuits required to drive all the transmitters can be reduced.

For example, as shown in Figure 2, six driver circuits can be used to drive all the transmitters in the transmitter array. Specifically, driver circuit one can drive the first transmitter in each group of transmitters at the same time, driver circuit two can simultaneously drive the second transmitter in each group of transmitters... and drive circuit six can simultaneously drive each group of transmitters The sixth transmitter in the transmitter. Wherein, in terms of circuit structure, the driving signal of the driving circuit 1 is sent to the first transmitter of each group of transmitters at the same time, so that the first transmitter in each group of transmitters can be simultaneously driven to emit laser light at the same time. Therefore, only the number of driver circuits corresponding to the number of transmitters in each group of transmitters is required to drive all the transmitters.

For example, as shown in FIG. 3, it is also possible to drive all the transmitters in the transmitter array with N driver circuits, where N is equal to the number of groups of transmitter groups. Specifically, driver circuit 1 can selectively drive one transmitter in the first group of transmitters, driver circuit 2 can selectively drive one transmitter in the second group of transmitters... The driver circuit N can selectively drive Drives one transmitter in the Nth group of transmitters. Wherein, which transmitter in the transmitter group each driver circuit sends the driver signal to can be selected by the control signal, and one control signal can be issued from the controller to control the N driver circuits simultaneously. Therefore, all transmitters can be controlled with the same number of driver circuits as the number of transmitter groups. Compared with the arrangement scheme of the driving circuit shown in FIG. 2 , the arrangement scheme of the driving circuit shown in FIG. 3 can reduce the length of the area covered by one driving circuit.

As described above, multiple lasers can be fired simultaneously by grouping the lasers, thereby reducing the number of driver circuits required.

For receivers, the lidar according to the present invention can reduce the number of receivers required. In the above, the embodiment in which N×M transmitters are provided has been described. In contrast, according to the first embodiment of the present invention, it is not necessary to provide N×M receivers but only N receivers. That is, the number of receivers need not be the same as the number of transmitters, but may be the same as the number of groups of transmitters.

As shown in Figure 1, the small box represents a receiver. And, one receiver may correspond to a group of transmitters, specifically, one receiver may correspond to 6 transmitters.

Since only one transmitter in a transmitter group is lasing at a time, one receiver can be provided for a group of transmitters. As shown in Figure 1, the six transmitters in the first transmitter group can emit laser light respectively. At this time, one receiver can receive 6 times to receive the laser light emitted from a group of transmitters.

And, the transmitter groups correspond to the receivers one-to-one. For example, the first receiver in the receiver array can receive the laser light from the first group of transmitters, and the Nth receiver in the receiver array can receive the laser light from the Nth group of transmitters. Wherein, by arranging the corresponding transmitter group and the receiver close enough, the laser received by the receiver is dominated by the signal of the corresponding transmitter and the signals of other transmitters are relatively weak due to the long distance.

Moreover, the setting positions of the transmitter group and the receiver can also be in a one-to-one correspondence. For example, the receiver array could be below/above the transmitter array, and the first receiver could be directly below the first transmitter group...the Nth receiver could be directly below the Nth transmitter group . Thus, the laser light emitted from the n-th emitter group can be easily incident on the n-th receiver.

Therefore, after the first transmitter of each transmitter group emits laser light, N pieces of distance information can be calculated from the received signal of the receiver. In this cycle, 6×N pieces of distance information can be obtained through 6 times of light emission. The above-mentioned method and structure can be used to obtain the distance information corresponding to the number of existing multiple transmitter/receiver line arrays by reducing the number of driving circuits and the number of receivers.

As described above, in the first embodiment with reference to FIG. 1 , the case where the receiver array and the transmitter array are arranged in a line array has been described. The present invention is not limited to this.

FIG. 4 is a schematic diagram illustrating a lidar according to a second embodiment of the present invention. As shown in FIG. 4 , the emitter array can be evenly distributed on a circumference, that is, the part protruding from the circumference in FIG. 4 is a single emitter, so that a situation including 24 emitters is shown in FIG. 4 . The number of emitters is not limited to this, and a larger number of emitters can be distributed around the circumference. By arranging in this way, the light emitted from the emitter can be made to be emitted in a 360° direction. Correspondingly, the receivers may be located above or below the circularly arranged transmitters as described above, or may be arranged at intervals between adjacent transmitters.

5 is a schematic diagram showing a driving circuit of a lidar according to a second embodiment of the present invention. In Fig. 5, the four block parts in the center represent four driving circuits, and the four driving circuits are arranged in the circle, wherein the circle does not necessarily represent the same plane located in the circle, and multiple driving circuits can also be located below or above the circle plane. And four driving circuits can be arranged around the center of the circle to drive a plurality of transmitters located on the circumference. For example, a plurality of driving circuits may be arranged point-symmetrically around the center of the circle.

The transmitter array and the receiver array arranged in a ring shape as described above transmit/receive in the same manner as according to the first embodiment.

By arranging the receiver and transmitter in a ring shape, the following effects can be achieved:

1) By setting up a ring-shaped lidar, distance measurement can be performed on an angular range of 360° without mechanical rotating parts.

2) Compared with the case of arranging as a linear array as shown in Figure 1, by arranging the transmitter array in a ring shape, the sum of the distances from the driver circuit to the transmitter array can be reduced as shown in Figure 5 (Figure 2). As shown, the distance from the driver circuit one to the first transmitter of the last transmitter group may be long, and the arrangement in a ring shape as shown in Figure 5 can avoid this problem).

3) The number of driving circuits and receiving circuits (such as transimpedance amplifiers, TDC (time-to-digital converters)) can be reduced.

4) The cost is relatively low, and it can be applied to products with low total price such as sweeping robots and low requirements for measurement accuracy.

5) Compared with each emitter to emit light individually, the time required for all emitters to emit light once can be reduced.

6) Since the receivers are distributed on a circumference and the transmitters and receivers are located at corresponding positions on the circumference, the laser light emitted by other transmitter groups received by the receiver can be reduced due to the different orientations of each receiver and transmitter group.

Those skilled in the art may know that some of the above effects are effects that the lidar of the first embodiment described with reference to FIG. 1 can also have.

The above-described embodiments of the apparatus and method are merely illustrative, and the separated units described therein may or may not be physically separated, and the components shown as units may or may not be physical units, that is, may be located in one location , or can be distributed over multiple network elements. Some or all of the modules can be selected according to actual needs to realize the technical solution of the present invention.

Claims (8)

1. A laser radar, characterized in that, comprising: Multiple emitters for emitting laser light; A plurality of receivers to receive the laser light emitted from the transmitter and reflected on the outside of the lidar; Among them, multiple transmitters are divided into multiple transmitter groups, the number of transmitters in each transmitter group is the same, the transmitters in one transmitter group are arranged adjacently, and each transmitter group has one transmitter at a time The transmitter emits laser light, and the transmitters located in the same position of each transmitter group in the plurality of transmitters emit laser light simultaneously; Among them, the number of receivers is the same as the number of transmitter groups, and one receiver receives the laser light emitted from the transmitters in one transmitter group and reflected on the outside of the lidar. 2. The lidar of claim 1, wherein, The plurality of transmitters are arranged in a line array form; The plurality of receivers are arranged in a line array form. 3. The lidar of claim 1, further comprising: Multiple drive circuits for driving the transmitter to emit laser light, The number of driving circuits is the same as the number of transmitters included in each transmitter group, and each driving circuit simultaneously drives a plurality of transmitters that emit laser light at the same time. 4. The lidar of claim 1, further comprising: Multiple drive circuits for driving the transmitter to emit laser light, Wherein, the driving circuit is connected to all the transmitters in one transmitter group, and drives one transmitter in one transmitter group at a time, and the number of driving circuits is the same as that of the transmitter group. 5. The lidar of claim 1, wherein, a plurality of said transmitters are distributed on a circumference; A plurality of said receivers are distributed over a circumference. 6. The lidar of claim 5, wherein, Also includes: a plurality of driving circuits for driving the transmitter to emit laser light, A plurality of the driving circuits are arranged inside the circumference where the transmitter is located. 7. The lidar of claim 6, wherein, A plurality of the driving circuits are arranged in a point-symmetric manner. 8. A lidar, comprising: Multiple emitters for emitting laser light and distributed on a circumference; A plurality of receivers to receive the laser light emitted from the transmitter and reflected on the outside of the lidar and distributed in a circle; Multiple drive circuits for driving the transmitter to emit laser light, Among them, multiple transmitters are divided into multiple transmitter groups, the number of transmitters in each transmitter group is the same, the transmitters in one transmitter group are arranged adjacently, and each transmitter group has one transmitter at a time The transmitter emits laser light, and the transmitters located in the same position of each transmitter group in the plurality of transmitters emit laser light simultaneously; Among them, the number of receivers is the same as the number of transmitter groups. One receiver receives the laser light reflected from the outside of the lidar after being respectively emitted from the transmitters in one transmitter group. The number of driver circuits is the same as the number of transmitters contained in each transmitter group, and each driver circuit simultaneously drives multiple transmitters that emit laser light simultaneously.

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