The invention relates to a vehicle treatment system in which at least one treatment device, in particular a washing gantry, and a vehicle to be treated or washed are moved relative to each other, having a collision detection device for width monitoring of a maximum treatment area of the vehicle treatment system, which, for monitoring a lateral boundary of the maximum treatment area, has at least one first optical sensor which is operated at a predetermined scanning frequency and outputs either a ‘covered’ event or a ‘not covered’ event for each scanning cycle, and a control unit for evaluating the output values of the first optical sensor.
It is a known problem in the field of vehicle treatment systems, in which there is a relative movement between a vehicle to be treated and a vehicle treatment device, that if the vehicle is incorrectly positioned, it can be damaged by a collision with the vehicle treatment device. Vehicle treatment systems, in particular gantry wash systems, which are operated without instruction personnel, therefore usually have a device for monitoring the boundaries of the maximum treatment space. This device is intended to avoid a possible collision of the vehicle treatment system with the vehicle to be treated. A width monitoring device is a device for monitoring the lateral boundaries of the vehicle treatment system or of the maximum passage width. If a vehicle is incorrectly positioned when entering the vehicle treatment system, whereby the boundaries of the maximum passage width are completely or partially exceeded by areas of the vehicle, there is a risk of collision with the vehicle treatment system or parts of it (in the case of a gantry wash system e.g. the gantry columns).
Collision detection devices for vehicle treatment systems are known from the prior art, which use tactile systems or mechanical deflection systems, such as safety edges, pull-wire switches, bending bars or similar devices, in order to prevent such damage. All these systems have in common that in case of contact between the corresponding tactile switching element and the vehicle, a circuit is executed which forces a stop of the relative movement.
However, all of these known solutions have the disadvantage that there is contact albeit weakened between the vehicle and the vehicle treatment device, which may cause damage to the paintwork. Furthermore, such contact-based systems enlarge the vehicle treatment device (in particular in the direction of passage), which is a disadvantage due to the limited space in vehicle treatment systems (which are usually located in halls). Finally, such systems are often perceived as unaesthetic by the customers.
From the prior art, the use of different contactless sensors (mainly in the form of light barriers) for collision monitoring is known and the Applicant has already thought about different contactless solutions in the past. Sensors, which were considered, were based, among other things, on radio/radar technology (continuous wave radar, frequency modulated continuous wave radar) or optical measuring methods (light barrier, time-of-flight, etc.). The first ones have the disadvantage that they only trigger at a certain minimum speed (CW radar, simple Doppler radar), and/or that they have a detection region that is too wide (FMCW). Optical measuring methods, however, have the disadvantage in the area of a vehicle treatment system that they are not triggered correctly due to disturbing influences such as spray mist, water jets or other media. All these sensors, which are classified as potentially suitable, have disadvantages that make reliable operation in the measurement task in hand difficult or even impossible. Tests carried out by the Applicant showed that the interference factors such as spray mist are very similar to the signal of an obstacle in such a way that the signal-to-noise ratio is not sufficient for further filtering.
Starting from this problem, the invention is therefore based on the object to provide a contactless collision detection device for a vehicle treatment system, which provides reliable obstacle detection even under adverse conditions in the vehicle treatment system.
According to a first aspect of the invention, a vehicle treatment system is provided in which at least one treatment device and a vehicle to be treated are moved relative to each other. The vehicle treatment system has a collision detection device for width monitoring of a maximum treatment area of the vehicle treatment system. The maximum treatment area is an area of the system in which a vehicle can be positioned so that a collision with the various devices and installations of the vehicle treatment system during the relative movement is excluded. Using a gantry wash system as an example, this could be a projection of the clearance area between the inner edges of the gantry columns in the direction of relative movement. The collision detection device of the vehicle treatment system according to the invention has at least one first optical sensor (e.g. a laser distance sensor or a light barrier) to monitor a lateral boundary of the maximum treatment area, wherein said sensor is operated with a predetermined scanning frequency during a treatment process or during a relative movement between vehicle treatment system and vehicle and outputs a (measured) value, e.g. a measured distance, for each scanning cycle. The collision detection device also has a control unit for the evaluation of the output values of the first optical sensor, which detects the measured values of the sensor (continuously) and for each measuring cycle assigns either a ‘sensor covered’ event (if an irregularity or a potential obstacle is detected) or a ‘sensor not covered’ event (if the measured value corresponds to an expected value without obstacle) to the value output by the first optical sensor. According to the invention, the detection region of the first optical sensor is oriented along a lateral boundary of the maximum treatment area of the vehicle treatment system monitored by the sensor. In particular, the detection region of the first optical sensor can be oriented along a vertical edge or flank of the treatment device limiting the treatment area when viewed in a front view of the vehicle treatment system (or viewed in the direction of relative movement). In addition, the detection region of the first optical sensor is oriented or arranged in such a way that it lies in front of the treatment device by a predetermined distance in the travel direction of the treatment device or precedes it so that there is a sufficient stopping distance if an obstacle is detected. The control unit is set according to the invention in such a way that it detects an impending collision if a predetermined number of consecutive cycles with a ‘covered’ event are scanned or detected at the first optical sensor.
The arrangement according to the invention of an optical sensor for collision monitoring in a vehicle treatment system described above utilizes the advantages of optical sensors by orienting the comparatively sharp (narrow) detection region along a boundary of the maximum treatment area, thus enabling efficient monitoring of this boundary. At the same time, the evaluation of the measurement signals according to the invention allows to compensate the susceptibility of optical sensors to interference factors by adjusting the sensitivity of the first optical sensor over the predetermined number of consecutively scanned cycles with a ‘covered’ event (threshold value).
According to a preferred exemplary embodiment of the invention, the treatment device may be a washing gantry which is moved or movable relative to a vehicle to be washed. In this case, the first optical sensor may be oriented along the inner edge or side of one of the gantry columns (plus a certain safety value, if applicable) to monitor the boundary of the maximum treatment area and to avoid a collision of a vehicle with the gantry column.
According to a further preferred exemplary embodiment of the invention, the control unit can evaluate the output values of the at least one first optical sensor in such a way that the number of consecutive cycles with a ‘covered’ event required to report an impending collision increases the slower the relative movement between the treatment device and the vehicle to be treated is. In other words, the threshold value of consecutive measurement cycles with a ‘sensor covered’ event at the first optical sensor required for obstacle detection can be varied in the course of a treatment, preferably in such a way that the threshold value is increased when the relative movement is slowed down.
Such a control has the advantage that the susceptibility to interference is improved when driving slowly. In particularly critical phases of a vehicle treatment, such as during foam application or in phases in which spray mist is generated, the system can be driven at a correspondingly low speed in order to avoid false triggering of the collision monitoring.
According to a further, preferred aspect of the invention, the collision detection device may comprise, in addition to the first optical sensor, a second optical sensor whose detection region is oriented at a predetermined distance and/or angle to the first optical sensor. In such a sensor array, the control unit can be adapted in such a way that it detects an impending collision at the lateral boundary monitored by the first and the second optical sensor if within a predetermined period of time, in particular simultaneously, a predetermined number of consecutive cycles with a ‘covered’ event is scanned or detected at the first optical sensor as well as at the second optical sensor.
A preferred aspect of the present invention is that the collision detection device can also be used during a treatment, e.g. during a relative movement between vehicle and system and with simultaneous spraying of the vehicle. By the selection and arrangement of the first and/or the second optical sensor according to the invention as well as the evaluation of the measurement results of the sensors according to the invention, collision monitoring can be provided which is less susceptible to interferences and which is fully operational even under the adverse conditions during the operation of a vehicle treatment system. While in the prior art position and orientation detection of the vehicle takes place exclusively before the actual treatment, the invention enables real-time collision monitoring during the treatment and can therefore also detect dangers that occur only after the vehicle is parked (e.g. persons or objects in the moving range).
As additional measures for improving the susceptibility to interference of the collision detection device, a predetermined sensor array can be used in the area of a boundary of the maximum treatment area to be monitored together with redundancy in the sensors.
According to a further, preferred exemplary embodiment of the invention, the detection region of the second optical sensor may be oriented along the same lateral boundary of the maximum treatment area as the detection region of the first optical sensor and also be oriented a predetermined distance ahead of the gantry but a predetermined distance behind the detection region of the first optical sensor in the travel direction. In other words, both redundant sensors may be oriented along the same lateral boundary of the maximum treatment area of the vehicle treatment system, but with a different advance in the direction of relative movement. This has the advantage that both sensors can be oriented exactly along the lateral boundary, but do not overlap in their detection region due to the different advances. In such an embodiment of the invention, the number of consecutive cycles required for reporting an impending collision with a ‘covered’ event at the second optical sensor (located/aligned closer to the treatment device) may preferably be less than the number of consecutive cycles required for reporting an impending collision at the first optical sensor. In other words, with a sensor array as described above, it is advantageous if the different advance between the two sensors is reflected in the threshold value for the required number of consecutive measurement cycles with ‘covered’ event, so that an obstacle detection is faster than with the first sensor, corresponding to the lower advance at the second sensor.
According to an alternative, preferred exemplary embodiment of the invention, the detection region of the second optical sensor, viewed in the direction of relative movement of the vehicle treatment system, can be located approximately at the level of the detection region of the first optical sensor and, viewed from the detection region of the first optical sensor, can be offset inwards towards the center of the treatment area by a predetermined distance. In such an arrangement, the first and second optical sensors are not aligned in the direction of relative movement but are arranged transversely to it (in the width direction of the vehicle treatment system). This has the advantage that it is not necessary to compensate for different advances between the two sensors.
According to a further, preferred aspect of the invention, the control unit can detect an impending collision if the number of consecutive cycles required for reporting an impending collision is simultaneously available at the first optical sensor and at the second optical sensor.
According to a further, preferred exemplary embodiment of the invention, the first and the second optical sensor can be arranged in such a way that the first and/or the second optical sensor are arranged on a cantilever arm on the treatment device, in particular at the level of the cross beam in a gantry wash system, and their detection region extends vertically downwards as seen from there. The sensors can thus measure vertically downwards from a cantilever arm and over the entire height of the treatment area.
According to another, preferred exemplary embodiment of the invention, the first and second optical sensors can be tilted in the travel direction away from the gantry to achieve the predetermined advance in the travel direction of the gantry. The advance orientation of the detection region of the sensors can thus be achieved either by positioning the sensors at a certain angle or by placing them on one or more cantilever arms. In this way, the collision detection can be placed unobtrusively directly in a front of the treatment device or in the upper part of the system.
According to a further, preferred exemplary embodiment of the invention, the first optical sensor and/or the second optical sensor can be a laser distance sensor. Compared to e.g. light barriers, these have the advantage that not only the presence of an obstacle is output, but also the absolute distance to it. This makes it possible to block out certain areas, e.g. permanently installed obstacles such as wheel guide rails, so that the error susceptibility can be reduced even further.
According to a further, preferred aspect of the invention, a measured distance can be compared by the control unit for each scanning cycle with a predetermined distance depending on the current position of the treatment device or a reference value, respectively, and a ‘sensor covered’ event can be output if the difference between the measured distance and the predetermined distance exceeds a predetermined threshold value; and a ‘not covered’ event can be output if the difference between the measured distance and the predetermined distance is within the predetermined threshold value. Minor measurement inaccuracies can be compensated in this way when using distance measuring sensors.
A further aspect of the invention relates to a method for evaluating an optical sensor for collision monitoring, which monitors a lateral boundary of a maximum treatment area of a vehicle treatment system with a predetermined scanning frequency, comprising at least the following steps:
BRIEF DESCRIPTION OF THE DRAWING FIGURES
In the preferred embodiment shown in
If the collision detection device 6 detects that a section of a parked vehicle protrudes beyond the lateral boundaries of the maximum treatment space B and consequently a collision is imminent if the treatment device 4 or the vehicle continues to move forward, it causes the relative movement between the treatment device 4 and the vehicle to be stopped by stopping the treatment device 4.
Pre-evaluations by the Applicant have shown that laser distance sensors, which not only indicate the presence of an obstacle but also determine the absolute distance to it, are in theory particularly suitable for implementing contactless width monitoring. Laser distance sensors offer the possibility to block out specific areas, in which an obstacle is consequently ignored. This makes it possible to ignore irregularities in the ground, wheel guide rails or similar fixed irregularities. In practice, laser distance sensors have not been used for collision monitoring in vehicle treatment systems so far, mainly due to their sensitivity to spray mist. The noise signal generated by spray mist has proven to be very similar in quality and time to the useful signal of a reference obstacle, so that a reliable evaluation seemed impossible so far.
The sensors on which the collision detection device 6 shown in
In the embodiment of
The collision detection device 6 of the vehicle treatment system 2 of
For the evaluation of the sensor output values, the following method is used in the sensor array of
In the collision detection device 6 of the embodiment shown in
The following method is used to evaluate the sensor outputs of this sensor array:
If two ‘covered’ reports are present at the same time (at both sensors 8, 12), an obstacle is reported.
The embodiment of
It goes without saying that also in the embodiment of
According to a preferred configuration example, the evaluation of the measurement results (S4 to S6) of the first optical sensor 8 described above is applied in parallel to a (redundant) second optical sensor 12. In this case, the evaluation step S7 can be adapted in an advantageous way and a collision is detected if the counter reading of the first optical sensor 8 and the counter reading of the second optical sensor 12 exceed the threshold value in the same measuring cycle.
It goes without saying that the preceding invention described in the concrete example of a gantry wash system is also applicable to vehicle treatment systems in which a vehicle is guided relative to stationary treatment devices, e.g. via a carrier. In such a case, the clearance/collision-free space is also defined by projection of the inner edges/inner contours of the treatment device in the direction of the relative movement, even if no actual movement of the treatment device takes place.
Deviating from the exemplary embodiment described above, an additional or alternative backward facing sensor can be used to detect impending collisions.
Number | Date | Country | Kind |
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10 2018 117 440.3 | Jul 2018 | DE | national |
This application is the United States national phase entry of International Application No. PCT/EP2019/069170, filed Jul. 16, 2019, and claims the benefit of priority of German Application No. 10 2018 117 440.3, filed Jul. 18, 2018. The contents of International Application No. PCT/EP2019/069170 and German Application No. 10 2018 117 440.3 are incorporated by reference herein in their entireties.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2019/069170 | 7/16/2019 | WO | 00 |