Lidar measuring device with self-diagnosis capability

Abstract

The present invention relates to a lidar measuring device (10) with the capability to self-diagnose its functionality, and to a corresponding method and computer program product, comprising: a lidar measuring unit (12), comprising at least one laser light source (23) for emitting a laser light beam (36) and a detector (30) for detecting the laser light beam (36) and generating a detector signal corresponding to the detected laser light beam (36); a rotatable outer unit (14) with at least one optical unit (32) which is designed to reflect a laser light beam (36) emitted by the laser light source (23) back to the detector (30); a diagnosis unit (16) for diagnosing a functionality of the lidar measuring device (10) based on a measurement of the laser light beam (36) when the laser light beam (36) is incident on the optical unit (32) and is reflected back to the detector (30) and on the detector signal during this measurement; and a coupling (18) between the lidar measuring unit (12) and the outer unit (14), said coupling being designed and configured to rotate the outer unit (14), based on an emission direction of the laser light source (23) in a plane which is perpendicular to a rotational axis of the rotatable outer unit (14).

Description

[0001] Lidar measuring device with self-diagnosis capability

[0002] The present invention relates to a lidar measuring device capable of diagnosing its functionality. The present invention further relates to a corresponding method and a computer program product.

[0003] A LIDAR (light detection and ranging) system is based on the emission of light pulses and the detection of the reflected light. For example, a time-of-flight measurement can be used to calculate the distance to the location of the reflection. A target can be detected by analyzing the received reflections. Regarding the technical implementation of the corresponding sensor, a distinction is made between scanning systems, which usually function based on micromirrors, and non-scanning systems, in which several transmitting and receiving elements are arranged statically next to one another (especially so-called focal plane arrays).

[0004] Currently, Lidar systems are known that determine distances based on, for example, the time-of-flight (ToF) method, or based on the optical displacement of a laser light beam. In this case, a reflection of a laser light beam is directed onto a CMOS or CCD sensor, or a similar sensor, preferably using a lens or optical unit. This sensor can have a linear or matrix-like pixel structure. Such Lidar systems are sometimes used in safety-relevant applications, such as road traffic or autonomous manufacturing systems with robots.

[0005] Lidar systems are known, among others, from the published patent applications DE 10 2020 211 369 A1 , DE 101 51 979 A1 and DE 10 2018 217 466 A1 .

[0006] The task is to verify the data acquired by such a lidar system. In particular, the reliability and functionality of the lidar system and its measurement results must be ensured. Particularly preferred is the creation of a way to design a lidar system with at least some redundancy.

[0007] This problem is solved by the subject matter of the subordinate claims.

[0008] The lidar measuring device with self-diagnostic capability for its functionality comprises a lidar measuring unit with at least one laser light source for emitting a laser light beam and a detector for detecting the laser light beam and generating a detector signal corresponding to the detected laser light beam. Furthermore, the lidar measuring device comprises a rotatable external unit with at least one optical unit configured to reflect a laser light beam emitted by the laser light source back to the detector. The laser light beam propagates along a known path during the reflection. This allows the distance traveled by the laser light beam to be known, allowing an expected detector signal to be precalculated, and the functionality of the lidar measuring device to be diagnosed based on the expected precalculated detector signal and the measured detector signal.Preferably, the lidar measuring device is a scanning lidar measuring device.

[0009] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be described below can be used not only in the respective combinations specified, but also in other combinations or alone, without departing from the scope of the present invention. In particular, the method and the computer program product can be implemented according to the embodiments described for the device in the dependent claims.

[0010] The accuracy of a lidar system's distance measurement can be verified by periodically splitting an outgoing laser light beam, for example, using beam splitter optics, and receiving it at a known distance from the receiver using known measurement methods. This creates a lidar system that is continuously calibrated and thus ensures reliable measurements. In addition, ambiguous measurements can be more easily interpreted or corrected, since a current relevant or calibration measurement is available for each measurement.

[0011] For this purpose, the lidar measuring device comprises a diagnostic unit which is designed to diagnose the functionality of the lidar measuring device based on the measurement of the laser light beam described above.

[0012] The laser light beam hits the optical unit and is reflected back to the detector. Based on the detector signal from this measurement, the diagnostic unit diagnoses the functionality of the lidar measuring device.

[0013] Preferably, the optical unit is designed as a beam splitter so that, in addition to the calibration or diagnostic measurement, a distance measurement can also be carried out.

[0014] Furthermore, the lidar measuring device comprises a coupling between the lidar measuring unit and the external unit. The coupling is designed and configured to rotate the external unit based on an emission direction of the laser light source in a plane arranged perpendicular to a rotation axis of the rotatable external unit. Consequently, the lidar measuring device can comprise a rotatable lidar measuring unit and a rotatable external unit. Both units can be configured to be rotatable relative to one another. In particular, both units can additionally be configured to be rotatable relative to a fixed system that does not move along with the system, in particular, that does not rotate.

[0015] In a preferred embodiment, the lidar measuring unit can therefore be rotated, whereby the external unit is rotated accordingly due to the coupling.

[0016] It is understood that a gear ratio can be set up during coupling so that the outdoor unit and the lidar measuring unit rotate in different directions and / or at different angular velocities.

[0017] This configuration allows for redundancy, for example, in the drive of the lidar measuring unit. Furthermore, the lidar measuring unit can comprise a detector with two individual detectors, both of which can be calibrated by a correspondingly designed optical unit. Preferably, each individual detector is a fully functional detector. It is understood that, for example, two laser light sources could also be present. In particular, it is conceivable that the laser light emitted by both laser light sources follows the same path after passing through a beam splitter.

[0018] A diagnostic unit for diagnosing the functionality of the lidar measuring device enables a quick and reliable determination of the reliability of the measurements of a lidar measuring device. The diagnostic unit can take various forms. In particular, the diagnostic unit can comprise a computer chip, in particular a special chip, e.g., a 1oo2 architecture, such as an FPGA, a comparator, or even software running on the special chip.

[0019] Preferably, the diagnostic unit is configured to compare an expected predefined distance and an actually measured distance during a measurement within the calibration range and, based on the comparison, to diagnose the functionality of the lidar measuring device. This comparison allows the functionality of the lidar measuring device to be determined in a technically simple and, in particular, rapid manner.

[0020] It goes without saying that all common methods of determining distances can be applied to a lidar measurement. In particular, the distance can correspond to and / or be converted into a phase shift and / or a time-of-flight. It goes without saying that calibration can also be performed based on raw data. The received data does not necessarily have to be converted into a distance. For example, calibration can also be performed based on a ToF, based on ADC (analog-to-digital converter) entries, or the like. It is clear that a distance results from various parameters, such as a time of flight, a phase shift, etc., and in this respect, distance can preferably be used synonymously for the aforementioned quantities.

[0021] An analog-to-digital converter (ADC) is a device for converting analog input signals into digital data, which can then be further processed or stored. Other names and abbreviations include ADC (analog-to-digital converter), A / D (analog-to-digital converter), or ADC for short.

[0022] Preferably, the coupling is designed and configured to rotate the external unit in a predefined relationship to an angular change in the emission direction of the laser light source in the plane arranged perpendicular to the rotational axis of the rotatable external unit. This ensures that a distance between the optical unit arranged on the external unit and the detector and the laser light source is known. Consequently, the expected detector signal can be precalculated. In particular, it is conceivable that several different distances can be used to diagnose functionality. Advantageously, the diagnostic unit determines an expected detector signal based on the emission direction of the laser light source and / or a rotational position of the external unit.Based on the expected detector signal, the diagnostic unit determines the functionality of the lidar measuring device, preferably by comparing the expected detector signal with the actually measured detector signal. In particular, it is conceivable to define a valid range so that the functionality of the lidar measuring device is diagnosed when the actually measured detector signal matches the expected detector signal within predetermined limits.

[0023] Preferably, the diagnostic unit is configured to mark all measurements between two successful diagnoses of functionality as trustworthy. Calibration can therefore be performed before and after a measurement, so that two successful calibrations can be assigned to one measurement. Trust and security are increased. Preferably, therefore, two successful functionality diagnoses are available for each measurement.

[0024] In this sense, calibration can be understood in particular as measuring the laser light beam projected by the optical unit onto the detector, and ensuring that this measurement, within predefined limits, agrees with an expected result. A calibration or calibration cycle therefore preferably involves a comparison of a measurement with an expected result and is preferably successful if functionality can be confirmed by the calibration cycle.

[0025] In a particularly advantageous embodiment, the diagnostic unit is designed to determine wear, contamination, and / or aging of the lidar measuring device based on an expected detector signal and an actually measured detector signal. In particular, wear, contamination, and / or aging of individual components of the lidar measuring device can be determined. By determining wear, contamination, and / or aging, a confidence parameter for the reliability of the measurement can be created. In particular, the detection of wear, contamination, and / or aging of the lidar measuring device enables early detection of a risk of failure or a loss of the reliability of the measurements.A lidar measuring device can be created which, in addition to self-diagnosis of its functionality, also allows self-diagnosis of wear and / or impairment of its measuring capability.

[0026] In particular, in combination with the above-described possibility of a redundant structure of at least some components of the lidar measuring device, redundant components can be switched over by determining wear, contamination and / or aging, so that measuring operation can be maintained reliably and for a long time.

[0027] In addition, insights can be gained into the durability and wear of individual components of the lidar measuring device.

[0028] Preferably, the diagnostic unit is designed to output an indication of a required adjustment of the lidar measuring device based on the determined wear, the determined contamination and / or the determined aging of the lidar measuring device and / or to adjust the lidar measuring device.

[0029] Adjustment is understood, for example, as adjusting the current and / or voltage of a laser light source and / or the current and / or voltage of a receiver unit. It is understood that, depending on the lidar measuring device, further adjustments are conceivable, which can preferably be carried out and / or initiated partially or fully automatically by the diagnostic unit.

[0030] For example, if contamination is detected, the light intensity can be increased to achieve a sufficient signal-to-noise ratio during a measurement with the lidar measuring device. It is understood that control commands for this purpose are preferably transmitted via a communication interface between the diagnostic device and the lidar measuring device.

[0031] A control command can also be a voltage and / or a current. In particular, it is conceivable that the diagnostic device does not actively instruct a control unit of the lidar measuring device, but instead applies an additional voltage or current to the detector, a measuring diode, and / or the laser light source in addition to the voltage supplied by the control unit of the lidar measuring device or a current supplied by the control unit of the lidar measuring device. This allows an existing lidar measuring device to be advantageously retrofitted with a diagnostic device without significant intervention in the control electronics.

[0032] By issuing a warning, the replacement of aged or worn components, or the cleaning of contaminated components, can also be initiated. This allows for sustainable, reliable measurements using the lidar measuring device.

[0033] The external unit preferably has an external base with a mechanical-optical unit that is permeable to electromagnetic waves of a specific wavelength, on which the optical unit is arranged. Additionally, the lidar measuring unit has an internal base. The coupling between the lidar measuring unit and the external unit is established by a force-fitting and / or form-fitting connection between the external base and the internal base. In the simplest case, the mechanical-optical unit can be a transparent hollow cylinder arranged on an annular base. In particular, the external base can have internal teeth and the internal base can have external teeth, which correspond, such that the coupling is established by the intermeshing of the external and internal teeth.

[0034] It is understood that other couplings are also conceivable, for example, a coupling via a traction mechanism, a frictional coupling, or a magnetic coupling. In other embodiments, the coupling can also be implemented electronically, with a drive for the lidar measuring unit and / or the external unit being controlled in accordance with a drive for the other unit.

[0035] The mechanical-optical unit can provide protection for the lidar measuring unit, which is preferably arranged within the mechanical-optical unit. In a particularly preferred embodiment, the mechanical-optical unit can form a wear part that is easily replaceable in the event of damage. This can provide protection for sensitive components, particularly for sensitive optical and electronic components of the lidar measuring unit.

[0036] The optical unit preferably has a reflective, in particular partially reflective, optical element in order to at least partially reflect the laser light to the detector. In a particularly preferred embodiment, the optical unit can be a beam splitter. By means of a reflective, in particular partially reflective, element, a distance measurement can also be carried out in parallel with a diagnostic measurement. Accordingly, the uptime or operating time of the lidar measuring unit is preferably not impaired by a functionality diagnosis. By means of an optical unit that comprises a reflective optical element, a passive unit, i.e. an electronics-free unit, can be used for calibration. It is understood that the optical unit can also comprise several reflective elements. In particular, it is conceivable to calibrate during each scan.For example, the optical unit could be a kind of cylinder formed by a collection of many vertical prisms.

[0037] In a preferred embodiment, the lidar measuring device is arranged partially, preferably completely, within the external unit. This makes it possible to create a compact lidar measuring device. By arranging the lidar measuring unit within the external unit, the lidar measuring unit can be operated protected from environmental influences. Particularly preferably, the lidar measuring unit is rotatable by means of an electric drive. It is conceivable here for the lidar measuring unit to be operatively connected to the electric drive by frictional engagement, for example by means of a magnetic field. It is understood that other operative connections between the electric drive and the lidar measuring unit are also conceivable, for example by means of a gearing, as described above. In particular, it is conceivable that two redundant drives are provided for the lidar measuring unit to increase reliability.

[0038] In a particularly preferred embodiment, the lidar measuring unit comprises a rotatable reflective, in particular partially reflective, optical deflection element arranged within the external unit. The coupling is established between the deflection element and the external unit. Furthermore, the laser light source and the detector are arranged outside the external unit. This allows the emission direction of the laser light to be varied by the deflection element. It is not necessarily necessary to rotate the entire lidar measuring unit. This allows part of the lidar measuring unit to be arranged outside the external unit, allowing the external unit to be made smaller. In particular, this allows the laser light source and the detector, as well as at least a large part of the electronics of the lidar measuring unit, to be arranged in a separate, protected housing.

[0039] Preferably, a position of the external unit and the emission direction of the laser light source relative to one another, caused by the coupling, can be determined using a one-step code, in particular a Reed-Solomon code (RS code). This allows the position of the external unit and the emission direction of the laser light source relative to one another to be determined robustly. The alignment of the external unit and the emission direction of the laser light source relative to one another can be determined in a manner that is not susceptible to errors, so that the position of the optical unit can be determined robustly. Confidence in a functional diagnosis and the measurement with the lidar measuring device can be increased. Particularly preferably, the laser light source is designed to emit a laser light beam with a predefined clock rate and / or a predefined pulse length.Additionally, the diagnostic unit is configured to validate a measurement based on a comparison of the predefined clock rate and / or the predefined pulse length of the emitted laser light beam with a clock rate and / or a pulse length of a received laser light beam. Preferably, the predefined clock rate or the predefined pulse length can be varied sequentially. Particularly preferably, the predefined clock rate or the predefined pulse length is varied randomly. This allows for a reliable determination of whether the received laser light beam corresponds to the emitted laser light beam. It can be ensured that deliberately induced external interference signals can be reliably identified as interference signals. A reliable diagnosis and / or measurement can be performed using the lidar measuring device.

[0040] In the presented design for a lidar measuring device, individual components can be used in a simple design, while other components can be used redundantly. For example, a focusing optics and a beam splitter for redundant laser light sources could be used simply. The laser light sources can be arranged with respect to the beam splitter such that the laser light beam from each of the laser light sources is emitted in the same direction after hitting the beam splitter. Furthermore, the design allows for the signal receivers, in particular the detectors, to be provided redundantly, i.e. in duplicate, so that one detector comprises two individual detectors. A drive unit, which in the simplest case could be an electric motor, for example, can also be provided in duplicate.

[0041] It is understood that the invention can also form a measuring lidar system without redundancy, with which a self-diagnosis of functionality is possible.

[0042] A particularly preferred embodiment comprises a planetary gear-like arrangement, wherein the external unit has an internal gearing at its base that meshes with an external gearing of a base of the lidar measuring unit. Particularly preferably, the lidar measuring unit can be driven by an electric motor with a pinion.

[0043] In this configuration, the outdoor unit and the lidar measuring device have different angular velocities. Consequently, there is a difference in the rotational speed of the outdoor unit relative to the lidar measuring unit, resulting in different distances between the optical unit on the outdoor unit and the laser light source and detector during operation of the lidar measuring device. These different distances can be advantageously used for functional analysis or calibration. The relative positions of these points are preferably determined using a one-step code.

[0044] In a particularly advantageous embodiment, the lidar measuring device comprises a protective unit that forms an outer protective sheath of the lidar measuring device. The optical components, preferably the mechanical components, and particularly preferably all components and parts of the lidar measuring device as defined above, are accommodated within the protective unit. The protective unit is made of a material permeable to electromagnetic waves of a specific wavelength. This allows for the creation of a robust lidar measuring device that is protected from environmental influences and is particularly suitable for exposed locations.

[0045] Mechanical components are understood to mean, in particular, the components of the lidar measuring device that can move at least one optical component of the lidar measuring device.

[0046] Optical components are understood to mean, in particular, the components of the lidar measuring device that can generate, receive and / or manipulate a laser light beam.

[0047] In other words, the protection unit can be used to create a system consisting of a protection unit and a lidar measuring device as previously defined, in which the lidar measuring device is accommodated in the protection unit.

[0048] The teaching disclosed here enables continuous calibration at various angular positions of the external unit relative to the lidar measuring unit. This is preferably achieved via an optical unit, which can be configured, in particular, as a beam splitter. The laser light beam emitted by the laser light source can strike this beam splitter and be split into two beam parts, one of which is used for distance measurement and the second part, in particular the reflection, is used for calibration.

[0049] It is understood that this optical unit can be present in multiple locations to enable a higher calibration frequency. Furthermore, the optical unit can also have a more complex structure and be suitable for multiple beam splitting. For simplicity, only a simple beam splitter is shown in the following embodiment.

[0050] The invention is described and explained in more detail below using selected embodiments in conjunction with the accompanying drawings. They show:

[0051] Figure 1 is a schematic perspective view of a lidar measuring device;

[0052] Figure 2 is a schematic plan view of an inner base, an outer base and a drive unit of the lidar measuring device;

[0053] Figure 3 is a plan view of the lidar measuring device according to Figure 1;

[0054] Figure 4 shows a schematic perspective view of a lidar measuring device with an external unit; Figure 5 shows, analogous to Figure 3, a top view of a lidar measuring device of Figure 5 with a redundant detector;

[0055] Figure 6 is a schematic perspective view of a lidar measuring unit according to Figure 5;

[0056] Figure 7 shows a front view of the lidar measuring unit according to Figure 6;

[0057] Figure 8 is a schematic representation of a detector and a diagnostic unit.

[0058] Figure 1 schematically shows a lidar measuring device 10. The lidar measuring device 10 comprises a lidar measuring unit 12 and an external unit 14. For reasons of clarity, the external unit 14 is shown without a mechanical-optical element.

[0059] In the embodiment shown, the external unit 14 has an internal toothing that corresponds to an external toothing of a base of the lidar measuring unit 12.

[0060] The lidar measuring unit 12 comprises a laser light source (not further specified) and a detector comprising two individual detectors. Furthermore, the lidar measuring unit 12 includes a diagnostic unit 16, which can be implemented, for example, in the form of a computer chip.

[0061] For reasons of clarity, a beam splitter has been omitted, which is preferably designed to direct an incoming laser light beam onto the two redundant individual detectors of the lidar measuring unit 12.

[0062] A coupling 18 between the lidar measuring unit 12 and the external unit 14 is established via the internal gearing of the external unit 14 and the external gearing of the lidar measuring unit 12. The lidar measuring device 10 further comprises an electric motor 20, which can drive the lidar measuring unit 12 via the external gearing by means of a pinion.

[0063] Figure 2 shows a base of the outdoor unit 14 as well as a base of the lidar measuring device 10 and the pinion 21 of the electric motor 20 in plan view.

[0064] The lidar measuring device 10 has a planetary gear-like structure, so that the lidar measuring unit 12, driven by the electric motor 20, rotates at a first angular velocity. The coupling 18 forces the external unit 14 to rotate in a fixed relationship to the lidar measuring unit 12.

[0065] Figure 3 shows a top view similar to Figure 2, including the lidar measuring unit 12. The lidar measuring unit 12 includes the diagnostic unit 16 in the form of a computer chip. Furthermore, the lidar measuring unit 12 includes a redundant laser light source 23 comprising a first laser emitter 22 and a second laser emitter 24.

[0066] The two laser emitters 22, 24 are arranged substantially perpendicular to each other and emit laser light onto a beam splitter 26. The beam splitter 26 is arranged at a 45-degree angle to the first laser emitter 22 and the second laser emitter 24. This allows laser light from the first laser emitter 22 to be reflected by the beam splitter 26. Laser light from the second laser emitter 24 can pass through the beam splitter 26, so that after the beam splitter, the laser light from the first laser emitter 22 and the second laser emitter 24 travel essentially the same path.

[0067] Furthermore, the lidar measuring unit 12 comprises a focusing optics 28 and a detector 30. In a preferred embodiment, the detector 30 can have a first individual detector and a second individual detector, thus also being designed redundantly. Not shown, but also conceivable, for the lidar measuring device to comprise a second drive unit, for example, a second electric motor.

[0068] Furthermore, in a variation of this embodiment, the electric motor 20 can drive the outdoor unit 14 instead of the lidar measuring unit 12. It is also conceivable that a motor is arranged on both the outdoor unit 14 and the lidar measuring unit 12 to create redundancy in the drive.

[0069] Figure 4 shows a perspective view of a lidar measuring device 10 with a lidar measuring unit 12 and an external unit 14.

[0070] The external unit 14 has a mechanical-optical unit 31, which is preferably designed as a transparent hollow cylinder. In contrast to the previously described embodiments, the external unit 14 has an optical unit 32, which is designed to at least partially reflect incident laser light back to the detector 30 of the lidar measuring unit 12. Particularly preferably, a portion of the laser light can be reflected back from the optical unit 32 to the detector 30, and a portion can be used for distance measurement. It is understood that the illustrated embodiment with only a single optical unit 32 serves to provide a better overview, and embodiments with two or more optical units 32 are conceivable.

[0071] Furthermore, in the embodiment shown, the lidar measuring unit 12 comprises a beam splitter 34 which is designed to project passing laser light onto a first individual detector and a second individual detector of the redundantly designed detector 30 of the lidar measuring unit 12.

[0072] For clarity, the mechanical-optical unit 31 of the external unit 14 is shown in a sectional view, allowing the lidar measuring unit 12 to be seen. It is understood that the mechanical-optical unit 31 of the external unit 14 is preferably designed as a transparent hollow cylinder. Figure 5 shows a top view of a lidar measuring device 10 with a lidar measuring unit 12 according to Figure 4.

[0073] Figure 5 also shows a laser light beam 36 during a calibration measurement or during a diagnostic check of functionality. The laser light beam 36 travels from the focusing optics 28 to the optical unit 32, from where it is reflected back to the beam splitter 34. The beam splitter 34 splits the laser light beam 36 and projects it onto the two individual detectors of the detector 30.

[0074] The distance exceeded by the laser light beam 36 is known, so the expected detector signal of the detector 30 is also known. This allows the diagnostic unit 16 to diagnose the functionality of the lidar measuring device 10 based on a comparison of the measured detector signal with the expected detector signal.

[0075] It is understood that the optical unit 32 can also allow a part of the laser light beam 36 to pass through, so that in addition to the calibration measurement as previously described, a distance measurement is also possible in this constellation.

[0076] Figure 5 shows a beam path of the laser light beam 36. It is understood that the advantageous coupling of the external unit 14 with the lidar measuring unit 12 results in various configurations in which the laser light beam 36 is reflected back from the optical unit 32 to the detector 30 and can be used for calibration or functionality diagnosis.

[0077] What is particularly advantageous here is that the planetary gear-like design results in different distances between the optical unit 32 and the laser emitters 22, 24, as well as the detector 30, so that the laser light beam 36 travels through different distances during calibration. Consequently, different detector signals are expected, and different detector signals can be used for calibration. Preferably, the diagnostic unit 16 can determine an orientation of the lidar measuring unit 12 relative to the external unit 14 using a one-step code, so that the positions of the individual elements relative to one another are known and the corresponding distances can be calculated.

[0078] It goes without saying that the corresponding values ​​can also be pre-calculated and retrieved from a memory.

[0079] Figure 6 shows the lidar measuring unit 12 in a schematic perspective view.

[0080] A laser light beam 36 striking the beam splitter 34 is split so that a partial laser light beam strikes a first individual detector and another partial laser light beam strikes a second individual detector of the redundant detector 30. It is understood that such a path of the laser light beam 36 is possible both for a calibration measurement and for a distance measurement.

[0081] The term laser light beam is to be understood broadly; in particular, a pulsed laser can also be used, so that the laser light beam describes the path taken by a laser light pulse.

[0082] In Figure ?, a lidar measuring unit 12 with a redundant detector comprising two individual detectors 30a and 30b is shown.

[0083] During a measurement and / or calibration measurement, the two individual detectors 30a, 30b can be compared with each other. If there is a difference in the native information of the sensors, i.e., if the detector signals of the first individual detector 30a differ from those of the second individual detector 30b, a fault in the respective individual detector 30a, 30b can be concluded.

[0084] For this purpose, simultaneous illumination of the individual components of the respective individual detectors 30a, 30b is preferably performed. This mutual adjustment can increase the robustness of the entire lidar measuring device 10. The reliability of the measurements is improved, and a high degree of safety can be achieved, particularly in critical technical areas. For example, such a high degree of safety may be necessary and / or advantageous in human-machine interactions.

[0085] Figure 8 schematically shows a redundant detector 30 comprising a first individual detector 30a and a second individual detector 30b with a diagnostic unit 16. The individual detectors 30a, 30b can each have a first measuring area 38 for distance measurement and a second calibration area 40 for calibration, with a laser light beam illuminating the corresponding areas for the corresponding measurement.

[0086] The detector signals of the individual detectors 30a, 30b can then be evaluated by means of the diagnostic unit 16.

[0087] In particular, it is conceivable for a laser light beam to have varying pulse lengths or a varying clock rate, so that a signal is impressed on the laser light beam upon emission, which is received by the individual detectors 30a, 30b and adjusted and verified by the diagnostic unit 16. This ensures that the laser light emitted by the lidar measuring unit 12 has been received by the individual detectors 30a, 30b.

[0088] After passing the diagnostic unit 16, the detector signals can be forwarded to a final processing system of the lidar measuring unit 12 or the lidar measuring device 10.

[0089] It is understood that the individual laser emitters 22, 24 can be diagnostically tested simultaneously or alternately during commissioning or even during operation. The laser light intensity is known due to the known physical boundary conditions of the interacting components of the lidar measuring device 10. Based on this, the beam intensity and any progressive aging of the laser emitters 22, 24 and / or the individual detectors 30a, 30b can be determined and, in particular, predicted. This minimizes the risk of a sudden failure. Furthermore, a reliable behavior prediction can be made using the lidar measuring device 10.

[0090] Furthermore, a potentially faulty reflection of the laser light beam can be detected based on expected laser intensity values.

[0091] It is understood that signal preprocessing of the detector data from the individual detectors 30a, 30b can be performed by the lidar measuring device 10 and / or the diagnostic unit 16. Downstream signal processing, for example, software-based downstream signal processing, can be reduced.

[0092] Angle information, for example, from incremental sensors, as well as single-step coded positions of the lidar measuring unit 12 and the external unit 14 can be compared. This allows a redundant and precise angular position of the components relative to each other to be determined, enabling a more precise overall distance measurement and more accurate calibration of the lidar measuring device 10.

[0093] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to those skilled in the art upon use of the present invention and upon careful analysis of the drawings, the disclosure, and the following claims. In the claims, the words "comprising" and "having" do not exclude the presence of further elements or steps. The undefined article "a" or "an" does not exclude the presence of a plurality. A single element or unit can perform the functions of several of the units recited in the claims. An element, unit, device, and system can be implemented partially or entirely in hardware and / or software.The mere mention of some measures in several different dependent claims should not be understood to mean that a combination of these measures cannot also be used advantageously. A computer program can be stored / distributed on a non-volatile data carrier, for example, on an optical storage device or on a solid-state drive (SSD). A computer program can be distributed together with hardware and / or as part of hardware, for example, via the Internet or via wired or wireless communication systems. Reference signs in the claims are not to be understood as limiting.

[0094] List of reference symbols

[0095] 10 Lidar measuring device

[0096] 12 Lidar measuring unit

[0097] 14 Outdoor unit

[0098] 16 Diagnostic unit

[0099] 18 Coupling

[0100] 20 electric motor

[0101] 21 pinions

[0102] 22 First laser emitter

[0103] 23 Laser light source

[0104] 24 Second laser emitter

[0105] 26 beam splitters

[0106] 28 Focusing optics

[0107] 30 detector

[0108] 30a, 30b single detectors

[0109] 31 mechanical-optical unit

[0110] 32 optical unit

[0111] 34 beam splitters

[0112] 36 laser light beam

[0113] 38 measuring range

[0114] 40 calibration range

Claims

Patent claims 1. A lidar measuring device (10) with self-diagnostic capability for its functionality, comprising: a lidar measuring unit (12) comprising at least one laser light source (23) for emitting a laser light beam (36) and a detector (30) for detecting the laser light beam (36) and generating a detector signal corresponding to the detected laser light beam (36); a rotatable external unit (14) having at least one optical unit (32) configured to reflect a laser light beam (36) emitted by the laser light source (23) back to the detector (30); a diagnostic unit (16) for diagnosing a functionality of the lidar measuring device (10) based on a measurement of the laser light beam (36) when the laser light beam (36) strikes the optical unit (32) and is reflected back to the detector (30), and the detector signal during this measurement;and a coupling (18) between the lidar measuring unit (12) and the outdoor unit (14), which is designed and configured to rotate the outdoor unit (14) based on an emission direction of the laser light source (23) in a plane arranged perpendicular to a rotation axis of the rotatable outdoor unit (14); 2. Lidar measuring device (10) according to claim 1, wherein the coupling (18) is designed and configured to rotate the external unit (14) in a predefined relationship to an angular change in the emission direction of the laser light source (23) in the plane arranged perpendicular to a rotation axis of the rotatable external unit (14).

3. Lidar measuring device (10) according to one of the preceding claims, wherein the diagnostic unit (16) is based on the emission direction of the Laser light source (23) and / or a rotational position of the external unit (14) determines an expected detector signal and determines a functionality of the lidar measuring device (10) based on the expected detector signal and the actually measured detector signal.

4. Lidar measuring device (10) according to one of the preceding claims, wherein the diagnostic unit (16) is designed to mark all measurements between two successful diagnoses of functionality as trustworthy.

5. Lidar measuring device (10) according to one of claims 3 or 4, wherein the diagnostic unit (16) is designed to determine wear, contamination and / or aging of the lidar measuring device (10) based on an expected detector signal and an actually measured detector signal.

6. Lidar measuring device (10) according to the preceding claim, wherein the diagnostic unit (16) is designed to output an indication of a required adjustment of the lidar measuring device (10) based on the determined wear, the determined contamination and / or the determined aging of the lidar measuring device (10) and / or to adjust the lidar measuring device (10).

7. Lidar measuring device (10) according to one of the preceding claims, wherein the external unit (14) has an external base and a mechanical-optical unit (31) permeable to electromagnetic waves of a specific wavelength, on which the optical unit (32) is arranged; the lidar measuring unit (12) has an internal base; and the coupling (18) between the lidar measuring unit (12) and the external unit (14) is established by a force-fitting and / or form-fitting connection between the external base and the internal base.

8. Lidar measuring device (10) according to one of the preceding claims, wherein the optical unit (32) has a reflective, in particular partially reflective, optical element in order to at least partially reflect the laser light to the detector (30).

9. Lidar measuring device (10) according to one of the preceding claims, wherein the lidar measuring unit (12) is arranged partially, preferably completely, within the external unit (14).

10. Lidar measuring device (10) according to one of claims 7 to 9, wherein the lidar measuring unit (12) is rotatable by means of an electric drive.

11. Lidar measuring device (10) according to one of the preceding claims, comprising a protective unit which forms an outer protective sheath of the lidar measuring device (10), wherein the optical components, preferably the mechanical components and particularly preferably all components and parts of the lidar measuring device (10) according to one of the preceding claims are accommodated within the protective unit and the protective unit is made of a material which is permeable to electromagnetic waves of a specific wavelength.

12. Lidar measuring device (10) according to one of the preceding claims, wherein the lidar measuring unit (12) comprises a rotatable reflective, in particular partially reflective, deflection element arranged within the external unit (14); the coupling (18) is arranged between the deflection element and the external unit (14); and the laser light source (23) and the detector (30) are arranged outside the external unit (14).

13. Lidar measuring device (10) according to one of the preceding claims, wherein a position of the external unit (14) and emission direction of the laser light source (23) relative to one another caused by the coupling (18) can be determined by means of a one-step code, in particular a Reed-Solomon (RS code).

14. Lidar measuring device (10) according to one of the preceding claims, wherein the laser light source (23) is configured to emit a laser light beam (36) with a predefined clock rate and / or a predefined pulse length; and the diagnostic unit (16) is configured to validate a measurement based on a comparison of the predefined clock rate and / or the predefined pulse length of the emitted laser light beam (36) with a clock rate and / or a pulse length of a received laser light beam (36).

15. A method for self-diagnosis of a lidar measuring device (10) according to one of the preceding claims, comprising the steps: Receiving at least one input signal with information about a detector signal of a measurement when the laser light beam (36) strikes the optical unit (32) and is reflected back to the detector (30); Determining an expected detector signal based on an emission direction of the laser light source (23) in a plane arranged perpendicular to a rotation axis of the rotatable outdoor unit (14) and / or a rotational position of the outdoor unit (14); Determining a functionality of the lidar measuring device (10) based on the expected detector signal and the measured detector signal.

16. A computer program product comprising program code for performing the steps of the method according to the preceding claim when the program code is executed on a computer.

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