A METHOD AND AN ARRANGEMENT FOR LOCALISING A FUELLING POINT ON A VEHICLE

Abstract: A method of locating a fuelling point with the aid of an optical sensor means, and more particularly for locating on one side of a vehicle chassis a fuel-tank flap (12) that has inwardly thereof a fuel-tank pipe (10) for fuelling of the vehicle concerned, and therewith cause a fuelling robot (2) to open said fuel-tank flap and to dock the robot head (3) of said fuelling robot with the fuel-tank pipe. The invention is characterised in that the area around the fuel-tank flap on said one chassis side is illuminated with light from a light source (13, 14) that gives a spectral irradiance which corresponds to or is greater than the spectral irradiance of the ambient lighting; in that the optical sensor means (23) is adapted to detect light from the light source that is reflected from said chassis side; and in that a computer (29, 31) is used to detect the position of the fuel-tank flap (12) on said chassis side in relation to the position of the robot head (3). The present invention also relates to an arrangement.

Description: A METHOD AND AN ARRANGEMENT FOR LOCALISING A FUELLING POINT ON A VEHICLE The present invention relates to a method and to an arrangement for localising a fuelling point on a vehicle, and more specifically for localising a fuel flap on one side of a vehicle chassis, where a fuel-tank pipe is located inwardly of said fuel-tank flap. An arrangement for the automatic fuelling of vehicles is described in Swedish Patent Specification 8901674-5. The arrangement according to this prior patent specification comprises a robot which includes a fuelling nozzle or corresponding device and which when the vehicle is located in a predetermined position in relation to the robot functions to move the fuelling nozzle automatically from a rest position to a vehicle fuelling position in response to sensing and control means. The fuelling nozzle includes a rigid first tubular element which is adapted to be moved by the robot towards an adapter provided with a hole associated with the vehicle fuelling point. A flexible second tube is arranged for movement within the first , rigid tube so that the free end of the second tube can be moved down into the fuel-tank pipe of the vehicle, whereafter fuel is pumped through the second tube and into the fuel tank. Swedish Patent Specification 9702011-9 describes an arrangement for positioning a robot of the kind described when automatically fuelling vehicles, primarily cars, wherein the robot head is moved from a rest position to a predetermined position relative to the fuel -tank pipe. The robot head carries an opening device which functions to open the fuel -tank flap in response to movements of the robot head. The invention according to this latter patent is characterised in that the positioning system includes an optical sensor means arranged on or in the vicinity of the robot and adapted to detect optically the position of the fuel-tank flap of a vehicle, parked for fuelling purposes, relative to the rest position of the robot head and therewith deliver to a robot computer a signal relating to said relative position. The computer is programmed to guide the opening device of said robot to open the fuel-tank flap in a predetermined movement plan. The sensor means functions to detect the position of the orifice of the fuel -tank pipe or of the adapter relative to the current position of the robot head after the fuel -tank flap has been opened, and therewith deliver to the computer a signal relating to this relative position. The computer then causes the robot head to effect said docking and to carry out said movements in a reverse order and therewith close the fuel-tank flap, when fuelling of the vehicle has been completed. One problem with using an optical sensor means of a video or laser type is that it is difficult in some circumstances to interpret the light arriving from one side of a vehicle with respect to the presence of a fuel-tank flap. The problems have several different causes. One cause is that different kinds of surrounding objects are mirrored in this side of the vehicle. The problem is particularly acute when said side of the vehicle is very shiny. The optical sensor means may also be affected by sunlight, either as a result of reflections or as a result of light incident on the sensor means. One overlapping problem in this respect is that the fuel-tank flap of a standard car is fully integrated in said side of the vehicle with no deviation in colour or shape. The present invention solves these problems. The present invention thus relates to a method of locating a vehicle fuelling point and more particularly of locating on one side of a vehicle chassis a fuel-tank flap which has situated inwardly thereof a fuel-tank pipe through which fuel is delivered to the fuel tank of said vehicle, with the aid of optical sensor means, such as to cause a fuelling robot to open the fuel-tank flap and to dock the robot head of said fuelling robot with the fuel-tank pipe, said method being characterised in that the area around the fuel -tank flap on one side of the vehicle chassis is illuminated with the aid of a light source which emits a spectral irradiance that corresponds to or is higher than the spectral irradiance of surrounding lighting; in that the optical sensor means is adapted to detect light from the light source reflected from said side; and in that a computer is used to detect the position of the fuel-tank flap on said chassis side relative to the position of the robot head. The invention also relates to an arrangement of the kind defined in the preamble of Claim 11 and having the substantive features set forth in said Claim. The invention will now be described in more detail with reference to exemplifying embodiments thereof and also with reference to the accompanying drawings, in which - Figure 1 illustrates schematically and from above a vehicle and a robot of the kind concerned positioned adjacent said vehicle; Figure 2 is a front view of a vehicle and a robot positioned adjacent thereto,- - Figure 3 shows part of one side of a vehicle with the fuel- tank flap open; - Figure 4 is a block schematic; - Figure 5 is a graph; and - Figure 6 is an image of a detected fuel-tank flap. Figure 1 illustrates schematically an automatic vehicle fuelling station, preferably for cars 1, wherein the station includes a robot 2 that has a robot head 3 which can move relative to the robot to a predetermined position relative to the fuel-tank pipe of the vehicle. The robot may be moveable in the direction of the arrow 4. The robot head 3 is moveable in the directions of arrows 5 and 6 and also in a direction perpendicular to the plane of the paper. The robot head 3 includes an outer tube and an inner tube which is axially moveable within and out of the outer tube, wherein the outer tube is intended to be docked with an adapter attached to the upper orifice of the fuel-tank pipe. Subsequent to docking the outer tube , the free forward end of the inner tube is intended to be projected down to a lower position in the fuel-tank pipe, whereafter fuel is delivered through the inner tube . The robot head 3 carries an opening device 11. The opening device 11 is intended to open a fuel-tank flap 12 of a vehicle 1 in response to movements of the robot head. An opening and docking sequence is performed in the following manner: The vehicle is placed in a predetermined position relative to the robot, although reasonable deviations are permitted. The robot is then positioned relative to the fuel- tank flap. When these manoeuvres have been completed, the robot computer causes the robot head to move in accordance with a predetermined movement plan, wherewith the robot head is brought into abutment with the fuel-tank flap and the opening device carried by said robot head caused to open said flap. In the next part of this movement plan, the robot head causes the outer tube to dock with the adapter, whereafter the inner tube is moved down into the fuel-tank pipe of the vehicle. Fuel is then delivered to the fuel tank through the inner tube in the fuel -tank pipe. When fuelling of the vehicle has been completed, the aforesaid movements are carried out in the reverse order, wherewith the fuel -tank flap is closed and the robot returns to its original position. The positioning system described in said patent specification includes an optical sensor means 23 which is arranged in connection with the robot 2. The sensor means is adapted to detect optically the position of the fuel-tank flap 12 on a vehicle parked for fuelling purposes relative to the rest position of the robot head 3 and therewith deliver to a robot computer a signal relating to said relative position. The computer 29 is programmed to guide the opening device 11 of the robot into abutment with the fuel -tank flap and to open said flap in accordance with a predetermined movement plan. After the fuel-tank flap has been opened, the sensor means 23 functions to detect the position of the fuel-tank pipe or the position of the adapter relative to the position of the robot head 3 at that time and to send to the computer 29 a signal relating to this relative position. The sensor means 23 thus detects the respective positions of both the fuel-tank flap and the adapter. The computer 29 then causes the robot head 3 to perform said docking operation, and, when fuelling of the vehicle is terminated, causes the robot to perform said movements in a reverse order and therewith close the fuel -tank flap. The optical sensor means is suitably mounted on the upper part of the robot and directed obliquely downwards as shown in Figure 2. The broken lines 24 in Figures 1 and 2 show the approximate extension of the area scanned by the sensor means . Because a groove-like recess or gap 25 is normally present between the fuel-tank flap and the surrounding chassis, the fuel -tank flap can be readily identified with the aid of a computer that includes a signal processing facility. The computer is programmed to search for a preferably rectangular or round shape formed by the groove-like gap. Figure 4 is a block schematic in which the robot computer is referenced 29. The computer memory is referenced 30. The sensor means 23 delivers to the computer signals that are processed in a signal processing circuit, which may be included in the computer or which may be a separate entity, either completely or partially, as indicated by the broken- line square 31, in which latter case the circuit is connected to the computer. When computations have been made, the computer activates manoeuvring circuits 32 which, in turn, activate the robot 2. The description given hitherto is also found in the aforesaid patent specification. According to the present invention, that side of the vehicle chassis on which the fuel -tank flap is situated is irradiated in the region of said flap with the aid of a light source that emits a spectral irradiance which corresponds to or is greater than the spectral irradiance of the ambient lighting. The optical sensor means is adapted to detect light from the light source that is reflected from said side of the chassis, and a computer is provided for detecting the position of the fuel-tank flap on said chassis side. The computer may be integrated with the computer 29 or may consist of a separate computer 31. The sensor means may also sense the position of the fuel-tank pipe. Accordingly, the expression fuel-tank pipe as used below and in the Claims is also intended to denote an embodiment in which an adapter is mounted in the orifice of the fuel -tank pipe. The optical sensor means includes a video camera of a suitable known kind. Its light sensitive element may be a two-dimensional array of CCD elements or C-MOS elements. By generating a spectral irradiance that corresponds to or is greater than the spectral irradiance of the surrounding lighting, the effect of said surrounding lighting is eliminated or suppressed. The illumination is therewith controlled, as is also the image to be detected by the sensor means, inasmuch that detection will not £>e affected by unknown contributions that have a disturbing influence on the result . Thus, a very reliable result is obtained with respect to the position of the fuel -tank flap and also of the position of the fuel -tank pipe, both with lighting conditions which when the present invention is not applied are favourable or unfavourable respectively for optical detection of the position of the fuel -tank flap. In the case of the embodiment shown in Figure 1, two illuminating panels 13, 14 are fixedly mounted in relation to the robot 2. The panels are sufficiently large to project sufficiently large luminous flux onto said side of the vehicle. The panels may have, for instance, a horizontal extension of 10 to 30 centimetres and a vertical extension of 50 to 150 centimetres. Light sources are mounted on the flat outwardly directed surface of respective panels, i.e. the surface facing towards the vehicle. The person skilled in this art will be able to adapt readily the number of light sources and the panel sizes required to achieve adequate illumination intensity. Instead of being positioned in the way shown in Figures 1 and 2, the panels may, alternatively, be placed on top of the robot 2 and directed obliquely downwards to that position where one side of a vehicle to be fuelled can be expected to be situated. According to one preferred embodiment of the invention, a further optical sensor means 15 is fixedly mounted on the robot head 3 and caused to detect the fuel-tank flap 12 and/or the fuel -tank pipe 7. According to one highly preferred embodiment of the invention, said chassis side is illuminated two times in succession, first from one direction and then from another. This enables the two images generated to be compared in said computer, wherewith reflections in said chassis side, shadows, etc., can be sorted out in an image processing procedure performed in the computer. Such image processing will suitably be of a known kind. Moreover, this allows different parts of the gap around the fuel-tank flap to be shown more clearly in one or the other illumination. According to one highly preferred embodiment, the area of the fuel-tank flap is illuminated with infrared light, IR-light. By IR-light is also meant so-called near IR-light, NIR-light. This light has a wavelength close to the wavelength of IR- light, such as a wavelength of 0.7 to 1.1 micrometer. IR-light has several advantages, one important advantage being that it is not visible to the human eye. Moreover, conventional CCD or C-MOS-based electronic cameras are very sensitive in the IR range, meaning that the equipment required will be relatively inexpensive. Figure 5 shows various curves in graph form. The X-axis relates to wavelength and the Y-axis relates to intensity and sensitivity respectively. The broken-line curve 16 shows the spectral irradiance of the sun. The full-line curve 17 shows the light emitted by IR-light-emitting diodes. The full-line curve 18 shows the sensitivity of a conventional electronic camera, and the chain-line curve 19 shows the sensitivity of the human eye . It will be evident from Figure 5 that wnen IR-light is emitted by light panels 13, 14 that include a large number of IR diodes of a well-known kind, the eye of an observer will not discern the light. A typical video camera, on the other hand, is very receptive to light. Furthermore, the intensity of sunlight is lower than the intensity of the sun in lower wavelength ranges. This means in practice that the intensity of the IR-light from the IR diodes will be more than sufficient for taking an image with a conventional camera and processing an image deriving from IR-light. According to another preferred embodiment , the area around the fuel -tank flap is irradiated with laser light of suitable wavelength, for instance a wavelength in the IR range. However, it is possible to use instead light within some other wavelength range that will enable the light on said chassis side to be distinguished from the general or ambient lighting, so that the image taken and processed in said computer will essentially derive from the light emitted from the panels 13, 14. It can be mentioned by way of example that when the irradiance from the sun's light at a certain wavelength range is 500 W per square meter and micrometer, the irradiance from the illumination will need to be about 700 in order to ensure that positive detection can be achieved with light from the illuminated or irradiated area. Although not preferred, it is obvious that light within the visible spectrum where the sun' s irradiance is high can also be used, provided that the illuminating effect is sufficiently high to suppress reflections in said chassis side originating from sunlight in relation to the light originating from said irradiation. In order to provide sufficient illumination, it is much preferred to illuminate said area with light that is transmitted in one or more short pulses with a power that provides greater brightness of the light reflected from said chassis side than the surrounding lighting in the light spectrum concerned. In this respect, the camera is synchronised with the light pulse so as to register solely the light reflected by said chassis side for the duration of said illumination. IR-light-emitting diodes and IR laser diodes can be pulsed in short bursts, for instance in bursts of 1 millisecond in duration, so as to deliver a considerably higher optical power output than when operated continuously. For instance, a diode intended to be supplied with 100 mA when operating continuously can be supplied with 1 A during a short pulse. According to another preferred embodiment, the optical sensor means is provided with a known spectral filter that has high transmission for the transmitted light and low transmission for other light. This will, of course, enhance the suppression of the effect that surrounding light gives rise to. The spectral filter may be an absorption filter of the bandpass type or lowpass type. The spectral filter may, alternatively, be an interference filter. In another preferred embodiment, the optical sensor means is caused to detect light reflected from said chassis side from two or more positions or angles relative to said side. This can be achieved by moving the camera or the robot relative to a stationary vehicle or by taking two or more pictures with the camera whilst the vehicle moves. For instance, the last meter or the last few meters through which the vehicle moves before stopping can be used to this end. The camera may also be rotated to take different pictures from different angles relative to said chassis side. The pictures taken from different positions relative to said chassis side can then be compared when processing the pictures or images in the computer and therewith establish the shape and position of the fuel-tank flap. Figure 6 is a picture that has been taken by illuminating one side of a vehicle chassis with IR-light. The fuel-tank flap is shown clearly as a square. Other lines on the picture derive from folds and edges in this side of the chassis. It will thus be evident that the present invention solves the problems mentioned in the introduction and provides a clear picture of a fuel-tank flap generally regardless of the ambient lighting. According to another preferred embodiment of the invention, said chassis side is .illuminated with laser light from a predetermined direction, so that a continuos line or a number of laser dots will appear on said side, said sensor means being adapted to detect the angle between its optical axis and the laser light that impinges on the sensor means. The angle is detected on the basis of where the reflected laser light is received by the light sensitive element of the camera. This enables the distance to said chassis side to be calculated by means of optical triangulation. The laser light is suitably transmitted by a diode laser 20 placed on the robot and provided with a lens which permits a horizontal plane of laser light to be transmitted. This plane thus occurs as a horizontal line on said chassis side and is reflected into the camera. It has been said above that a further optical sensor means 15 may be mounted fixedly on the robot head and caused to detect the fuel-tank flap and/or the fuel-tank pipe. This additional sensor means is used conveniently when the robot head is moved forwards to a position close to the fuel-tank flap. This enables the position of the flap to be determined with great precision. The additional sensor means can also be used to detect the position of the fuel -tank pipe with great accuracy, after the flap has been opened but before docking has been carried out. When the additional sensor means is located close to the fuel-tank flap or close to the fuel-tank pipe, it is possible that the positions of the flap and pipe can be detected without requiring any special lighting to this end. However, the aforementioned panels 13, 14, or a separate light source (not shown) , may be used in conjunction with detecting said positions with the aid of the additional sensor means . In order to enable a fuel-tank pipe and its position to be identified more easily, it is preferred that a marking 21 which will reflect the prevailing light is applied on or adjacent to said pipe. A number of exemplifying embodiments have been described above. It will be obvious, however, that the position of the camera or cameras can be varied, as can also the position of the illuminating devices. It will also be understood that any suitable light that gives the aforedescribed effect can be transmitted and detected. It will therefore be understood that the present invention is not restricted to the above described and illustrated exemplifying embodiments thereof, and that variations and modifications can be made within the scope of the following Claims .

Claims: CLAIMS 1. A method of locating a fuelling point with the aid of an optical sensor means, and more particularly for locating on one side of a vehicle chassis a fuel-tank flap (12) that has inwardly thereof a fuel -tank pipe (10) for fuelling of the vehicle concerned, and therewith cause a fuelling robot (2) to open said fuel-tank flap and to dock the robot head (3) of said fuelling robot with the fuel-tank pipe, characterised in that the area around the fuel -tank flap on said one chassis side is illuminated with light from a light source (13, 14) that gives a spectral irradiance which corresponds to or is greater than the spectral irradiance of the ambient lighting; in that the optical sensor means (23) is adapted to detect light from the light source that is reflected from said chassis side; and in that a computer (29, 31) is used to detect the position of the fuel-tank flap (12) on said chassis side in relation to the position of the robot head (3) . 2. A method according to Claim 1, characterised in that an additional optical sensor means (15) is fixedly mounted on the robot head (3) and caused to detect the position of the fuel-tank flap (12) and/or the position of the fuel-tank pipe (10) . 3. A method according to Claim 1 or 2 , characterised in that said chassis side is illuminated at least two times in succession, where said side is first illuminated from a first direction and then from a second direction. 4. A method according to Claim 1, 2 or 3, characterised in that the optical sensor means is caused to detect light reflected from said chassis side from two or more positions relative to said side. 5. A method according to Claim 1, 2, 3 or 4 , characterised by illuminating said area with IR-light. 6. A method according to Claim 1, 2, 3 or 4, characterised by illuminating said area with laser light. 7. A method according to Claim 1, 2, 3, 4, 5 or 6, characterised in that said area is illuminated with light transmitted in one or more short pulses with a power that gives a higher light intensity reflected from the chassis side than the ambient lighting at the light spectrum concerned. 8. A method according to Claim 1, 2, 3, 4, 5, 6 or 7, characterised in that the optical sensor means (23, 15) is provided with a spectral filter which has high transmission for the transmitted light and low transmission for other light. 9. A method according to Claim 1, 2, 3, 4, 5, 6, 7 or 8, characterised in that said chassis side is illuminated with laser light from a predetermined direction so that a line or a number of laser points appear on said chassis side; in that the sensor means (23) is adapted to detect the angle between its optical axis and the laser light that is reflected towards the sensor means (23) ; and in that the distance to said chassis side is calculated by optical triangulation. 10. A method according to any one of the preceding Claims, characterised by applying to or adjacent to the fuel-tank pipe a marking (21) that reflects the prevailing light. 11. An arrangement for locating a fuelling point with the aid of an optical sensor means, and more particularly for locating on one side of a vehicle chassis a fuel-tank flap (12) which has located inwardly thereof a fuel-tank pipe (10) for fuelling the vehicle, in order to cause a fuelling robot (2) to open the fuel-tank flap and to dock the robot head (3) of the fuelling robot with the fuel -tank pipe, characterised by one or more light sources (13, 14) for illuminating one side of the vehicle chassis in the area of the fuel -tank flap, said light sources being adapted to give a spectral irradiance that corresponds to or is greater than the spectral irradiance of the ambient lighting; in that the optical sensor means (23) is adapted to detect light from the light source that is reflected from said chassis side; and in that the arrangement includes a computer (29, 31) for detecting the position of the fuel-tank flap (12) on the chassis side in relation to the position of the robot head (3) . 12. An arrangement according to Claim 11, characterised by a further optical sensor means (15) fixedly mounted on the robot head (3) and adapted to detect the position of the fuel-tank flap (12) and/or of the fuel-tank pipe (10) . 13. An arrangement according to Claim 10, 11 or 12, characterised in that the light sources emit IR-light. 14. An arrangement according to Claim 10, 11 or 12, characterised in that the light sources emit laser light. 15. An arrangement according to Claim 10, 11, 12, 13 or 14, characterised in that the light sources are adapted to transmit light in one or more short pulses with a power that gives a higher intensity of light reflected from the chassis side than the ambient lighting in the light spectrum concerned. 16. An arrangement according to Claim 10, 11, 12, 13, 14 or 15, characterised in that the optical sensor means (23, 15) includes a spectral filter which has high transmission for the light emitted by the light sources and low transmission for other light. 17. An arrangement according to Claim 10, 11, 12, 13, 14, 15 or 16, characterised by a laser (20) which is adapted to emit laser light from a predetermined direction so that a line or a number of laser points will appear on said chassis side; in that the sensor means (23) is adapted to detect the angle between its optical axis and the laser light that is reflected onto the sensor means (23) ; and in that the computer (29, 31) is programmed to calculate the distance to said chassis side by optical triangulation. 18. An arrangement according to any one of Claims 10-17, characterised in that a marking (21) which will reflect the prevailing light is applied on or adjacent to the fuel-tank pipe.

Inventors: AAHLEN HANS, HOLMGREN ANDERS, AAHLEN, HANS, HOLMGREN, ANDERS
Applicants: AAHLEN HANS, AUTOFILL PATENT AB, HOLMGREN ANDERS, AAHLEN, HANS, HOLMGREN, ANDERS
Application year: 2000
Main classification: B67D5
IPC codes: B67D5, G01B11