The invention relates to a vehicle with a sensor system as well as to a method configured to warn a vehicle, in particular a driver-less one, operated without any human intervention and/or automatically controlled, in particular lane-bound, about a collision of the driving vehicle with an obstacle, to avoid the obstacle, to stop the vehicle when an obstacle is being detected and/or to issue a warning to a control center.
From DE 10 2018 110 852 A1, there is known a device for securing a machine or automatically controlled movable device, in particular a handling device such as a robot or an AGV (“automated guided vehicle”). This document provides for a safety sensor system for detecting objects in a working space, at distance from, or in an environment of the device. The safety sensor system comprises a tactile sensor system and a proximity sensor system, wherein the sensors used are based on optical measurement principles.
From DE 10 2014 206 473 A1, there is known a method providing automated assistance to a driver of a lane-bound vehicle. To this end, a camera is provided at the front side of the vehicle both on the left and the right-hand side which detect a clearance in front of the vehicle and which interact with an evaluation unit to warn about an imminent collision.
From DE 10 2004 041 821 A1, there is known a touch-less safety system using ultrasound or microwave sensors for securing a machine-controlled handling device. There, the proximity sensors used can be ultrasound or microwave sensors. Further, it is described that the ultrasound or microwave sensors may be combined with another sensor which operates based on a different physical principle.
Another touch-less safety system for securing a machine-controlled handling device is known from DE 10 2013 021 387 A1. The system operates based on a capacitive sensor system.
The invention relates to a vehicle according to claim 1 and to a method according to claim 15.
The dependent claims relate to preferred embodiments of the invention.
Compared to the prior art, the vehicle having the inventive sensor system and the inventive method offer the advantage that comparatively small obstacles such as pipelines, obstacles with different cross-sections and degrees of reflection, dangling power cables, bundles of pipes, corner lights, cable looms, thin posts etc. projecting into the driveway of the vehicle can be well and reliably detected, even when the conditions are bad such as when there is oncoming light or the sun is blinding, when there is smoke or fog or when measurements are taken at an oblique angle downwards.
Moreover, sensitivity of the detection as well as minimum distance for the warning thresholds of the warning system may easily be adjusted via the provided evaluation and control electronics.
Now, the driving speed of the vehicle can automatically be either reduced or the vehicle will be stopped immediately and/or a control center will be informed.
Furthermore, with sensors provided in the region of the corners of the vehicle, it is not only possible to monitor the region in front of the vehicle but also a region sideways of the vehicle. This may be achieved with additional sensors as well.
By providing at least two sensors located in spatial proximity to each other, the signals or measured values of a sensor can be validated, and plausibility checked, respectively, using the signals or measured values from the other sensor. Thereby, reliability of detection is increased, and false alarms are avoided.
In this respect, it is particularly advantageous that the two sensors located in spatial proximity to each other are arranged in particular perpendicularly to the direction of travel and in parallel to the ground offset from each other and operate at different wavelength ranges, or when the maximum sensitivity of both sensors is at a different wavelength.
Furthermore, it is advantageous to combine sensors located in spatial proximity to each other which operate based on the principle of travel-time measurement.
Another advantageous configuration is to combine sensors which operate based on the principle of travel-time measurement with sensors which operate based on the phase-comparison method.
When using sensors which operate based on the principle of travel-time measurement, it is advantageous that they ensure a resolution of at least 2×2 pixels. By combining sensors with a resolution of 2×2 pixels and an inventively narrow field of view (“FOV”) with sensors with a resolution of 8×4 pixels and also an inventively narrow field of view, a safe measurement distance and a safe detection are advantageously ensured, in particular when it comes to objects with small cross-section and little remission.
It has proven to be particularly advantageous to have a configuration of one pair of sensors each in the region of a left and of the right corner of the vehicle, preferably at the front side of the vehicle.
As to the terminological relationship of the terms front side, rear side, left and right, as used herein, it should be noted that a vehicle comprised by the invention may move on land or by sea in several directions of travel. In particular, a steering shaft may be installed. Further, the invention may include a tracked vehicle. Yet, the vehicle may also look identical from all sides, and in this case the front side is the “front” face pointing to the direction of travel while moving.
Preferably, the vehicle is an automatically controlled vehicle or AVG, respectively.
The invention will be explained in more detail with reference to the drawings and the following description.
In the example explained, the vehicle 10 has four optical sensor elements 20, 21, 22, 23 in the region of its front side 11 (relative to the direction of travel or the usual direction of travel) or, generally, in the region of one side of the vehicle 10, the optical sensor elements being connected to a central on-board machine control 30, serving as an evaluation and control electronics, via bus lines 31. The bus lines 31 preferably are traditional CAN bus lines which may optionally be secured as well. The signals and the distance values provided by the sensors 20, 21 and 22, 23 are evaluated by the evaluation and control electronics. When receiving prespecified signals, e.g., when falling below defined distance values, the machine control 30 reacts, e.g., by reducing the driving speed, thereafter immediately stopping the vehicle and notifying the control center.
Moreover, the vehicle 10 has additional four sensor elements 24, 25, 26, 27 in the region of its rear side or, generally, at a side opposing the side with the sensor elements 20, 21, 22, 23. Like the optical sensor elements 20, 21, 22, 23, these may also be optical sensor elements such that the vehicle may likewise drive forwards and backwards and provides for collision avoidance in both directions of travel, respectively. Basically, the additional sensor elements 24, 26, 27 may also be other sensor elements as they have already been used with AGVs for collision avoidance in the prior art.
Meanwhile, it should be noted that although not shown in the
The second exemplary embodiment of
The third exemplary embodiment of
In the exemplary embodiments explained, the sensor interface electronics 40 and the machine control 30 are each provided on board. Alternatively, the machine control 30 may also be positioned remotely from the vehicle 10 and be connected thereto, and communicating therewith, in particularly wirelessly.
At least one of the optical sensor elements 20, 21, 22, 23, preferably all of them, has a field of view 50, 51, 52, 53 which can also be referred to as detection area or measurement field, extending horizontally and/or vertically across a viewing angle range of less than 3 degrees. Here, the horizontal viewing angle range is designated with a, compare
Preferably, the horizontal viewing angle range α and/or the vertical viewing angle range a′ is/are in the range of from to 1.5 degrees or from 0.5 to 1.5 degrees.
Particularly preferably, both the vertical and the horizontal viewing angle range α, a′ are less than 3 degrees, preferably in the range of from 0.1 to 1.5 degrees or from 0.5 to 1.5 degrees.
The fields of view, or detection areas, 50, 51, 52, 53 each define the detection and measurement area, respectively, of the respective optical sensors 20, 21, 22, 23 within which objects, events or changes can be sensed.
The optical sensor elements 20, 21, 22, 23 are each arranged in pairs in spatial proximity to each other to the left and to the right in the region of the left corner 13 and the right corner 14 of the vehicle 10. Preferably, the optical sensor elements 20 and 21 or 22 and 23, respectively, are each arranged next to each other or one behind the other or offset from each other. To check plausibility of the individual sensor signals or measurement values, it is advantageous to provide the sensors 20 and 21 as well as 22 and 23 each with a vertically different angle. This angle which may also be referred to as elevation angle β is preferably in the range of from 25 degrees to 60 degrees.
As shown in
The optical sensor elements 20, 21, 22, 23 are each selected, and adapted, respectively, in a way that the highest detection sensitivity of the two optical sensor elements 20 and 21 located in spatial proximity to each other is in each case at a different wavelength, preferably in the non-visible near infrared. The same holds for the optical sensor elements 22 and 23. Consequently, the highest sensitivity of the first optical sensor element 20 and of the third optical sensor element 22 is, e.g., at 905 nm and of the second optical sensor elements 21 and of the fourth optical sensor element 24 is, e.g., at 850 nm.
Basically, it is advantageous that the highest sensitivity of the optical sensor elements 20, 21, 22, 23 in each case is within a wavelength range of from 600 to 1100 nm.
Further, the optical sensor elements 20, 21, 22, 23 are each selected, and adapted, in a way that the two sensor elements and 21 or 22 and 23, respectively, located in spatial proximity to each other ensure a measurement distance which is as identical or similar as possible. Thus, together with the different wavelengths of the highest detection sensitivity of the optical sensor elements 20 and 22 or 21 and 23, respectively, also possible collision objects of different sizes and with different degrees of reflection are detected almost at the same time.
When the respective fields of view between the sensor elements and 21 or 22 and 23, respectively, are positioned in a different vertical orientation, it is possible for a first one of the two optical sensor elements 20, 21 or 22, 23, respectively, to detect an obstacle earlier than the second one of the two optical sensor elements 20, 21 or 23, 24, respectively. Thus, the measurement signal from one of the optical sensor elements, e.g., from the optical sensor element 20 or 22, respectively, which is reacts at first can be validated and plausibility checked, respectively, by the minimally delayed resulting measurement signals of the optical sensor elements 21 or 24, respectively, to safely avoid a possible collision and/or false alarms.
A multi-pixel resolution of the optical sensor elements 20, 21 or 23 and 24, respectively, is of particular advantage. Thereby, thanks to the movement of the AGV, an additional plausibility check is made by successive different pixels sampling a possible collision object and thus increasing detection reliability, while still ensuring detection reliability in case of a failure of the second sensor element.
Further, using different wavelength ranges or using different wavelengths of the highest detection sensitivity for the optical sensor elements 20 and 22 compared to the optical elements 21 and 24 and/or offsetting the fields of view 51 laterally and vertically from 50 or 53 from 52, respectively, serves the same purpose, namely increasing the reliability of obstacle detection and mutual validation and plausibility check, respectively, of sensor signals or measurement values.
In particular, the lateral offset allows for the validation of signals or measurement values of obstacles in the region of the corners 13, 14, 15, 16 of the vehicle since such obstacles enter into the respective fields of view 50, 51, 52, 53 at slightly different times.
Different wavelength ranges or different wavelengths of the highest detection sensitivity allow for sensor signals or measurement values to be allocated to the respective optical sensor 20, 21, 22, 23 such that a decision can already be made as to whether the reflected signal to be processed originates from the optical sensor element 20 or the optical sensor element 21, e.g. What is even more important is the finding that obstacles are not detected equally well at all wavelength ranges and under all environmental conditions (rain, sunlight, smoke, fog . . . ). Thus, to counteract this problem, sensors with different wavelength ranges or different wavelengths of the highest detection sensitivity and at the same time high insensitivity to interfering light, e.g., are used.
In summary, it is preferably provided for that the two sensor elements 20 and 21 or 22 and 23, respectively, located in spatial proximity to each other are configured, and interact with the evaluation and control electronics 30, 40, in a way that the signals or measurement values of one of the two sensor elements can be plausibility checked, or validated, by signals or the measurement values from the other of the sensor elements.
Preferably, the optical sensor elements 20, 21, 22, 23 are positioned at the corners 13 and 14 in the upper region of the vehicle 10 such that the respective field of view 50, 51, 52, 53 of the sensor elements 20, 21, 22, 23 will not be obstructed in vertical and/or horizontal direction.
Further, the sensor elements 20 and 21 as well as 22 and 23 arranged in the region of, or in proximity to, the left front corner 13 of the vehicle 10 and in the region of, or in the proximity to, the right front corner 14 of the vehicle 10 are preferably positioned and configured in a way that they each have a horizontal and/or vertical field of view 50, 51, 52, 53 which extends across an area in front of the vehicle 10 as well as in an area slightly sideways next to the vehicle, thus allowing for the surroundings of the front corners 13, 14 of the vehicle 10 to be observable not only from in front of the vehicle 10 but also from a bit sideways therefrom.
Preferably, the optical sensor elements 20, 21, 22, 23 have such a measurement distance that obstacles at a horizontal distance of from 5 m to 10 m, in particular from 3 m to 8 m, and at a height of from 4 m to 7 m can be safely detected by the vehicle 10.
The optical sensor elements 20, 21, 22, 23 each have a detection area, or sampling conus area, respectively, defined by the respective horizontal and vertical viewing angle range α, α′ and the respective measurement distance, with said areas preferably having a rectangular (e.g., with an 8×4 pixel matrix), square (e.g., with a 2×2 pixel matrix), circular or elliptical section in lateral direction towards the vehicle 10 and vertically towards the ground.
Preferably, the fields of view or measurement fields 50, 51, 52, 53 each extend at an angle of from between 25° to 60° relative to the longitudinal axis upwards and to the level of the vehicle 10 to a ground on which the vehicle 10 is moving, up to a height which corresponds at least to the height of the vehicle 10, compare
Preferably, all of the optical sensor elements 20, 21, 22, 23 each have a field of view or measurement field 50, 51, 52, 53 which extends up to a height of at least 6 m or at least 7 m.
For example, laser optical distance, range and speed sensors are used as the optical sensor elements 20 and 23, preferably a measuring laser with infrared wavelengths of about 905 nm, target laser, red, 635 nm and a laser-pulse travel-time method, with the measurement area of which particularly preferably ranging between 8 to 150 m at a remission of the measurement object of from 6% to 8%.
Preferably, sensors ensuring a measurement distance of up to 10 m at a wavelength of about 940 nm are used as the optical sensor elements 21 and 22.
Advantageously, ToF sensors in connection with a vertical cavity surface emitting laser (VCSEL) transmitting module with a wavelength of 850 m can be used as the optical sensor elements 20 and 23 as well as 21 and 22. The receiving module preferably consists of an 8×4 pixel matrix. Particularly advantageously, this sensor is provided with a permanent self-monitoring using a control pixel.
Optical sensor elements 20, 21, 23, 24 with a multi-pixel resolution offer the advantage that they allow for an additional plausibility check since successive different pixels detect a possible collision object and thus ensure detection reliability even when one sensor element fails, thanks to the movement of the AGV.
To provide for an optimum detection, the measurement frequency of the optical sensor elements 20, 21, 22, 23 should be at least 100 Hz. At a duty cycle of 100%, e.g., an encoded signal is preferably used which is pulsed at a predetermined frequency to be detected by the receiver as useful signal. Such an encoded signal is also used to suppress the influence of interfering light.
Number | Date | Country | Kind |
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102020129233.3 | Nov 2020 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/DE2021/100883 | 11/5/2021 | WO |