CN115568793A

CN115568793A - Laser rangefinder and self-cleaning equipment

Info

Publication number: CN115568793A
Application number: CN202211185135.0A
Authority: CN
Inventors: 王淼
Original assignee: Beijing Rockrobo Technology Co Ltd
Current assignee: Beijing Rockrobo Technology Co Ltd
Priority date: 2022-09-27
Filing date: 2022-09-27
Publication date: 2023-01-06

Abstract

The utility model provides a laser rangefinder and self-cleaning equipment, laser rangefinder includes: a laser configured to emit laser light; a beam splitter configured to split the laser light into a test laser light and a reference laser light; a reference component configured to receive and reflect the reference laser light; a detector configured to receive and detect the reference laser light reflected by a reference component and the test laser light reflected by an obstacle; and a processor configured to determine a distance between the obstacle and the spectroscope based on a detection result of the detector.

Description

Laser rangefinder and self-cleaning equipment

Technical Field

The utility model relates to a laser detection technology field particularly, relates to a laser rangefinder and self-cleaning equipment.

Background

The laser ranging device has been widely used in the fields of industrial fields, intelligent transportation, smart home and the like, especially in the field of automatic cleaning equipment such as cleaning robots, and has become a very important navigation and obstacle avoidance sensor of the cleaning robot by virtue of the advantages of low cost, high reliability, easy integration and the like.

Disclosure of Invention

Some embodiments of the present disclosure provide a laser ranging device, including:

a laser configured to emit laser light;

a beam splitter configured to split the laser light into a test laser light and a reference laser light;

a reference component configured to receive and reflect the reference laser light;

a detector configured to receive and detect the reference laser light reflected by a reference component and the test laser light reflected by an obstacle; and

a processor configured to determine a distance between the obstacle and the beam splitter based on a detection result of the detector.

In some embodiments, the processor is configured to:

determining a first detection distance between the reference component and the beam splitter based on the reference laser light detected by the detector;

determining a second detection distance between the obstacle and the beam splitter based on the test laser light detected by the detector; and

correcting the second detection distance based on a deviation between the calibration distance between the reference component and the beam splitter and the first detection distance to obtain a corrected distance between the obstacle and the beam splitter.

In some embodiments, the detector comprises:

an imaging lens configured to transmit the reference laser light reflected by a reference member and the test laser light reflected by an obstacle; and

an imager configured to receive the reference laser light and test laser light transmitted by the imaging lens,

the spot position of the reference laser projected on the imager does not overlap with the spot position of the test laser projected on the imager.

In some embodiments, the processor is configured to determine the distance between the obstacle and the beam splitter based on triangulation.

In some embodiments, the reference component has a reflective surface.

In some embodiments, the laser ranging device comprises a laser ranging module, and the laser, the beam splitter, the detector, and the reference component are integrated within the laser ranging module.

In some embodiments, the laser ranging device includes a laser ranging module, the laser, the beam splitter, and the detector are integrated in the laser ranging module, and the reference component is located outside the laser ranging module.

In some embodiments, the laser is configured to emit continuous laser light or to emit intermittent laser light having a preset duty cycle.

In some embodiments, the laser comprises at least one of a point laser, a line laser.

In some embodiments, the laser light has a wavelength greater than 808nm.

Some embodiments of the present disclosure provide an automatic cleaning device, including the laser ranging device of the previous embodiments.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure. It is to be understood that the drawings in the following description are merely exemplary of the disclosure, and that other drawings may be derived from those drawings by one of ordinary skill in the art without the exercise of inventive faculty. In the drawings:

fig. 1 is a schematic structural diagram of a laser ranging device according to some embodiments of the present disclosure;

FIG. 2 is a schematic diagram of laser triangulation provided by some embodiments of the present disclosure;

fig. 3 is a schematic structural diagram of an automatic cleaning device according to some embodiments of the present disclosure.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, the present disclosure will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present disclosure, not all embodiments. All other embodiments, which can be derived by one of ordinary skill in the art from the embodiments disclosed herein without making any creative effort, shall fall within the scope of protection of the present disclosure.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of another, identical element in a commodity or a device comprising the element.

In the art, the measurement accuracy of a laser distance measuring device, such as a distance measuring instrument based on the trigonometry principle, a laser radar, etc., is affected by many factors, including but not limited to, thermal defocusing of a lens assembly, temperature drift of a pitch angle of the lens assembly, temperature drift of a pitch angle of a laser, thermal deformation and humidity deformation of a structural support, thermal stress variation of bonding glue, and thermal deformation and humidity deformation of an optical lens.

Laser rangefinder receives above-mentioned factor to influence, and the measuring accuracy under the high low temperature is obvious than the degradation when normal atmospheric temperature (calibration temperature), leads to being equipped with laser rangefinder's automatic cleaning equipment, cleans machine people etc. for example, and the problem such as collision or leak and sweep appear when ambient temperature is lower or higher seriously influences user experience. During transportation, an automatic cleaning device, such as a cleaning robot, may be placed in a high temperature and high humidity environment for a long time, and non-metallic parts (optical lens, structural support, etc.) of a laser ranging device thereon may be irreversibly deformed, which affects ranging accuracy. In view of the above situation, a self-correction system is required to be installed inside the laser ranging device for correcting the ranging deviation caused by the above factors in real time or at regular time.

In the related art, a precision drift correction curve may be written in an internal processor of the laser ranging device, where the abscissa of the curve is, for example, the ambient temperature in which the laser ranging device operates, and the abscissa is the ranging correction value, and the unit is, generally, millimeters. The laser ranging device obtains the temperature of a working environment through an internal or external temperature sensor, then searches a corresponding ranging correction value on the precision drift correction curve according to the temperature value of the working environment, and a ranging correction algorithm running in the laser ranging device performs comprehensive operation according to the real-time ranging value and the searched ranging correction value and outputs the corrected ranging value.

The technical scheme is adopted to ensure the production efficiency, the same precision drift correction curve is written into all the laser ranging devices, the precision drift correction curve is obtained through a background test in a research and development stage and a batch trial-manufacturing stage, the laser ranging devices are difficult to adapt to all the laser ranging devices in mass production based on induction and compromise of data with a certain sample size, and the problem of over-correction or under-correction is inevitably caused. In addition, for most laser distance measuring devices, the precision drift correction curve is a monotonous curve, and the premise that the same precision drift correction curve is written in all the laser distance measuring devices is that the precision drift directions of all the laser distance measuring devices are consistent by default. However, in the actual production process, due to the influences of material batches, process control capability and the like, it is inevitable that the precision drift direction of part of the laser ranging devices is not monotonous and even opposite to the existing precision drift curve, and at the moment, the laser ranging devices correct the ranging values according to the existing precision drift curve, so that the error correction is caused, and the measurement result is seriously degraded. Moreover, the accuracy drift correction curve can only correct the distance measurement error of the laser distance measuring device introduced by the change of the environmental temperature, and cannot correct the distance measurement error of the laser distance measuring device introduced by the environmental humidity.

In another related art, the ranging accuracy of the laser ranging apparatus is ensured by sacrificing the production efficiency. Specifically, the same precision drift correction curve is not uniformly written into the internal processor of the laser ranging device any longer, and each laser ranging device acquires the respective precision drift curve in a temperature-changing environment (incubator), so that the problem of over-correction or under-correction can be effectively avoided, and the error correction caused by non-monotonous precision drift direction and reverse precision drift direction can be effectively avoided.

By adopting the scheme, the production efficiency is low, the production cost is high, the requirement of large-scale consumer product production cannot be met, and the method is only suitable for the production of high-value small-batch products. Moreover, the accuracy drift correction curve can only correct the distance measurement error of the laser distance measuring device introduced by the change of the environmental temperature, and cannot correct the distance measurement error of the laser distance measuring device introduced by the environmental humidity.

In order to overcome the above-mentioned defect, the present disclosure provides a laser ranging device, which includes: a laser configured to emit laser light; a beam splitter configured to split the laser light into a test laser light and a reference laser light; a reference component configured to receive and reflect the reference laser light; a detector configured to receive and detect the reference laser light reflected by a reference component and the test laser light reflected by an obstacle; and a processor configured to determine a distance between the obstacle and the beam splitter based on a detection result of the detector.

By introducing the reference component, the distance measurement result determined based on the test laser light received by the detector and reflected by the obstacle is corrected in real time based on the reference laser light received by the detector and reflected by the reference component. The laser ranging device can independently correct the ranging value of each automatic cleaning device while ensuring the generation efficiency, and the measurement result is ensured.

Alternative embodiments of the present disclosure are described in detail below with reference to the drawings.

Fig. 1 is a schematic structural diagram of a laser ranging device according to some embodiments of the present disclosure. As shown in fig. 1, a laser distance measuring device 100 is characterized in that the laser distance measuring device 100 comprises a laser 10, a beam splitter 20, a reference component 30, a detector 40 and a processor.

The laser 10 is configured to emit laser light, and the laser includes, for example, a driving circuit to drive the laser to generate laser light, which may be continuous laser light or intermittent laser light at a certain duty cycle. In some embodiments, the laser is, for example, an infrared band laser with a wavelength of 808nm and above, and the laser wavelength includes, but is not limited to 808nm, 850nm, 905nm, 940nm, and the like. In some embodiments, the laser may be a single point laser, a line laser, or a combination thereof.

The beam splitter 20, such as a beam splitter or the like, is configured to split the laser light emitted by the laser 10 into a test laser light and a reference laser light, the test laser light is used for performing laser ranging, and the laser triangulation ranging principle or the like may be employed to measure the distance between an object, such as an obstacle, and a laser ranging device. The reference laser is used to perform a modified laser ranging. In some embodiments, the beam splitter 20 may also perform the splitting operation using a light-transmissive cover of the laser ranging device, with stray light reflected by the light-transmissive cover as a reference beam.

The reference component 30 is configured to receive and reflect the reference laser, a distance between the reference component 30 and the optical splitter 20 is calibrated in advance, and is recorded as a calibration distance, and the reference component 30 may be made of a material that is slightly affected by temperature and humidity.

The detector 40 is configured to receive and detect the reference laser light reflected by the reference component 30 and the test laser light reflected by the obstacle 200. The detector 40 is, for example, a photodetector, including but not limited to CMOS, CCD, SPAD, SIPM, and the like.

The processor is configured to determine the distance between the obstacle 200 and the beam splitter 20 based on the detection result of the detector 40, which is the corrected measured distance, and may be considered as a more accurate distance between the laser ranging device 100 and the obstacle 200.

In the laser ranging device in some embodiments of the present disclosure, by introducing the reference component, the ranging result determined based on the test laser light reflected by the obstacle received by the detector is corrected in real time based on the reference laser light reflected by the reference component received by the detector. The laser ranging device can independently correct the ranging value of each automatic cleaning device while ensuring the generation efficiency, and the measurement result is ensured.

The laser ranging device of the present disclosure, for example, employs a laser triangulation ranging principle to perform ranging, and the laser triangulation ranging principle is specifically described below.

Fig. 2 is a schematic diagram of laser triangulation distance measurement according to some embodiments of the present disclosure, as shown in fig. 2, the laser emitter 1 and the lens assembly 2 are located on a reference line, a distance between the two is s, a focal length of the lens assembly 2 is f, and an included angle between a laser emitting direction of the laser emitter 1 and the reference line is β. s, f and β are known quantities.

It is assumed that the target object 3 is reflected back to the lens assembly 2 under the irradiation of the point-like laser light, and the imaging position on the image plane of the lens assembly 2 is an imaging point P.

From the geometrical knowledge, a similar triangle can be made, in particular, an auxiliary line is made parallel to the laser emitting direction and passes through the lens assembly 2, the auxiliary line intersects the image plane of the lens assembly 2 at an auxiliary point P'. The triangle formed by the laser emitter 1, the lens assembly 2 and the target object 3 is similar to the triangle formed by the lens assembly 2, the imaging point P and the auxiliary point P'.

As shown in fig. 2, x is an example between the image point P and the auxiliary point P', q represents a distance from the target object 3 to the reference line, and d represents a distance between the laser transmitter 1 and the target object 3. As shown in fig. 2, two similar triangles can be obtained according to the above:

f/x＝q/s

further, q = fs/x

x may be divided into two parts, x = x1+ x2 as illustrated in fig. 2, x1 being the distance between the auxiliary point P' and the optical axis of the lens assembly 2, and x2 being the distance between the imaging point P and the optical axis of the lens assembly 2.

Wherein x1= f/tan β

x2 may be determined according to the size and in particular the imaging position of the pixel unit of the detection member located at the image plane of the lens assembly.

Finally, the distance d = q/sin β between the laser transmitter 1 and the target object 3 can be obtained by calculation.

In some embodiments, the working principle of the laser ranging device with the implementation of the correction of the measured distance is as follows:

a first detection distance between the reference component 30 and the beam splitter 20 is determined based on the reference laser light detected by the detector 40. The first detection distance is determined based on, for example, the above-mentioned principle of laser triangulation, and the beam splitter 20 may be regarded as the exit point of the reference laser.

A second detection distance between the obstacle 200 and the beam splitter 20 is determined on the basis of the test laser light detected by the detector 40, which second detection distance is determined, for example, on the basis of the laser triangulation principle described above, and the beam splitter 20 can be considered as the exit point of the test laser light.

The second detection distance is corrected based on a deviation between the calibration distance between the reference member 30 and the beam splitter 20 and the first detection distance to obtain a corrected distance between the obstacle 200 and the beam splitter 20.

The laser ranging device can measure the distance between the reference component 30 and the optical splitter 20 as a calibration distance by using the laser triangulation distance measuring principle under the conditions of a preset environment, such as a preset temperature and humidity. The reference component 30 is made of a material which is less affected by temperature and humidity, and the calibration distance between the reference component 30 and the optical splitter 20 is basically not changed along with environmental factors, and is basically fixed after the laser ranging device is assembled. When the laser ranging device is affected by changes of ambient temperature, humidity and the like, the ranging drift occurs, and the first measured distance between the reference component 30 and the optical splitter 20 measured by adopting the laser triangulation ranging principle also drifts at the same time, that is, the first measured distance deviates from the calibration distance. The second measured distance between the obstacle 200 and the beam splitter 20, which is also measured using the laser triangulation principle, will also drift, i.e. deviate from the actual distance between the obstacle 200 and the beam splitter 20. The deviation between the first measured distance and the calibrated distance can be used to correct the second measured distance obtained by measurement in real time during the measurement of the obstacle distance, so as to obtain a corrected distance substantially close to the true distance between the obstacle 200 and the beam splitter 20.

In some embodiments, as shown in FIG. 1, the detector 40 includes an imaging lens 41 and an imager 42. The imaging lens 41 is configured to transmit the reference laser light reflected by the reference member 30 and the test laser light reflected by the obstacle 200. The imager 42 is configured to receive the reference laser light and the test laser light transmitted by the imaging lens 41. The imaging lens 41 images the reference laser and the test laser on the imager 42 respectively, so as to facilitate subsequent measurement calculation.

As shown in fig. 1, the imager 42 is located at an image plane of the imaging lens 41, which is substantially perpendicular to the optical axis AX of the imaging lens 41, and the distance between the imager 42 and the imaging lens 41 is the focal length of the imaging lens 41.

The spot positions of the reference laser light projected on the imager 42 do not overlap with the spot positions of the test laser light projected on the imager. In particular, the test laser and the reference laser can be set to different light-emitting angles. As shown in fig. 1, an auxiliary line passing through the center line of the imaging lens 41 and parallel to the light emitting direction of the test laser intersects the imager 42 at a point a, and two end points of the imager 42 are points B and C, respectively. The imaging spots on imager 42 of the test laser light reflected by obstruction 200 are located between AB and the imaging spots on imager 42 of the reference laser light reflected by reference assembly 30 are located between AC, and they do not overlap. So set up, can avoid referring to the mutual interference of laser and test laser, avoid influencing the range finding effect.

In some embodiments, the processor is configured to determine the distance between the obstacle and the beam splitter based on laser triangulation, as described above. In other embodiments, the processor may also be configured to measure the distance between the obstacle and the beam splitter based on other ranging methods, such as pulse ranging, phase ranging, and the like.

In some embodiments, the light intensity of the measuring laser is greater than that of the reference laser, and under the condition that the total power of the laser light source is constant, the light intensity of the reference laser can be reduced as much as possible, so that normal distance measurement is satisfied, and the laser energy can be concentrated on the measuring laser as much as possible, so that the laser distance measuring device can measure a far obstacle.

In some embodiments, the reference component 30 has a reflective surface. The reference component 30 can be, for example, a high reflectivity target, and the detection of the detection distance is achieved by using a reference laser with low light intensity. In other embodiments, the reference component 30 surface may also be coated with a highly reflective coating, while increasing the exposure time and gain of the detector.

In some embodiments, the laser ranging device 100 comprises a laser ranging module, and the laser 10, the beam splitter 20, the detector 40, and the reference component 30 are integrated within the laser ranging module. The laser ranging module is compact in structure, the components, particularly the optical splitter 20 and the reference component 30 are relatively fixed in position, the components are basically not affected by the external environment, and the calibration distance between the optical splitter 20 and the reference component 30 is basically kept unchanged.

In some embodiments, the laser ranging apparatus 100 includes a laser ranging module, the laser 10, the beam splitter 20, and the detector 40 are integrated in the laser ranging module, and the reference component 30 may be located outside the laser ranging module. The reference member 30 needs to be made of a material that is less affected by temperature and humidity, so as to avoid the influence of deformation on the self-correction accuracy.

Fig. 3 is a schematic structural diagram of an automatic cleaning device according to some embodiments of the present disclosure, and as shown in fig. 3, some embodiments of the present disclosure provide an automatic cleaning device 300, such as a cleaning robot, a sweeping and mopping machine, and the like. The automatic cleaning device 300 comprises the laser ranging device 100 of the previous embodiment. The laser ranging device 100 is, for example, disposed on a sidewall of the automatic cleaning apparatus 300, and is configured to detect an obstacle in a forward direction of the automatic cleaning apparatus 300, and determine distance information of the obstacle, so that the automatic cleaning apparatus can perform obstacle avoidance operation.

The automatic cleaning equipment provided by the embodiment of the disclosure can not be interfered by external environment factors, accurately measures the distance information of the obstacle, and is beneficial to obstacle avoidance operation of the automatic cleaning equipment.

Finally, it should be noted that: in the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The system or the device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The above examples are only intended to illustrate the technical solutions of the present disclosure, not to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A laser ranging device, comprising:

a laser configured to emit laser light;

2. The laser ranging device as claimed in claim 1, wherein the processor is configured to:

correcting the second detection distance based on a deviation between the calibration distance between the reference component and the optical splitter and the first detection distance to obtain a corrected distance between the obstacle and the optical splitter.

3. A laser ranging device as claimed in claim 1 or 2, wherein the detector comprises:

an imager configured to receive the reference laser light and a test laser light transmitted by the imaging lens,

4. The laser ranging device according to claim 1 or 2, wherein the processor is configured to determine the distance between the obstacle and the beam splitter based on triangulation.

5. A laser ranging device as claimed in claim 1 or 2, wherein the reference component has a reflective surface.

6. The laser ranging device as claimed in claim 1 or 2, wherein the laser ranging device comprises a laser ranging module, and the laser, the beam splitter, the detector and the reference component are integrated within the laser ranging module.

7. The laser ranging device according to claim 1 or 2, wherein the laser ranging device comprises a laser ranging module, the laser, the beam splitter and the detector are integrated in the laser ranging module, and the reference component is located outside the laser ranging module.

8. The laser ranging device as claimed in claim 1 or 2, wherein the laser is configured to emit continuous laser light or to emit intermittent laser light having a preset duty cycle.

9. The laser ranging device as claimed in claim 1 or 2, wherein the laser comprises at least one of a point laser, a line laser.

10. A laser ranging device as claimed in claim 1 or 2, wherein the wavelength of the laser light is greater than 808nm.

11. An automatic cleaning apparatus, characterized in that it comprises a laser distance measuring device according to any one of claims 1 to 10.