Patent Application
20090132165
The invention relates to a method and an arrangement for determining a position of a vehicle. Specifically, the invention relates to determine the position of a vehicle relative another vehicle.
There are a number of different occasions when multiple machines are cooperating during construction or the like, such as when covering roads with asphalt a number of vehicles are cooperating. The result of the work may be based on how the machines move/work relative one another. Taking the asphalt laying process as an example, a main vehicle during the asphalting process is an asphalt layer, that is, the vehicle that provides the asphalt on the surface. The asphalt layer distributes the asphalt with a suitable width and thickness. Behind the asphalt layer is one or a plurality of rollers processing/compacting the asphalt. This compacting process may be performed numerous times, that is, a plurality of compacting rollovers, within a certain amount of time. These parameters, number of rollovers and the time, are also dependent on the weather, the temperature of the asphalt, and the like. The quality of every step of the process influences the final result of the process and consequently how many years the surface will be able to hold. In order to provide a good quality layer the asphalt layer should be moving continuously which may imply that asphalt need to be refilled during the process. An infra red camera may be used to scan the asphalt for temperature variations.
Positioning systems are today rare but the demand for such systems will increase in the future due to a desire of the contractors to commit to a higher degree of quality of the asphalt but also a desire to focus more on the annual cost over the lifetime of the work than the initial cost. The purchasing of a project is today based on area, amount and prescribed prescription of the asphalt, which does not premier the potential of offering higher quality of the asphalt than the quality that today exist.
The systems that today are coming out on the market are based on measuring GPS-systems, wherein GPS equipment is arranged on both rollers as well as on the asphalt layer. General GPS equipment has a precision of 3 to 15 meters and to provide enough precision one would need advanced GPS equipment, such as RTK-GPS equipment or the like, which results in expensive sensors on every participating vehicle. These systems will not work in environments wherein the GPS are disturbed or blocked such as below bridges, in tunnels, tall buildings or trees close to the road, or the like.
Document U.S. Pat. No. 5,646,844 A discloses monitoring and coordination apparatuses, e.g. for earth movers on building site, which shares position information from several machines to generate a common, dynamically updated site database showing positions of machines and site progress in real time using GPS-equipment.
It is desirable to provide a relative cheap and rigid positioning system of cooperating vehicles that will work in an environment wherein the GPS function may be disturbed.
In order to achieve an object as stated above the invention relates to a relative positioning system for determining positioning of a second vehicle relative a first vehicle comprising an optical device mounted on the first vehicle and arranged to record an image of an area wherein the second vehicle is positioned, and a processor arranged to process the recorded image, wherein the processor is arranged to process the recorded image so as to determine the position of the second vehicle relative the first vehicle based on measurements in the recorded image of at least one marker arranged on the second vehicle.
In an embodiment the measurements may be length measurements between three markers arranged on the second vehicle.
In addition may each marker be uniquely identifiable in the image and wherein the processor is arranged to determine an orientation of the second vehicle relative the first vehicle based on the positions of the uniquely identifiable markers.
The invention further relates to an arrangement comprising a first vehicle and at least one second vehicle and wherein the first vehicle comprises a relative positioning system according to the above.
In an embodiment the second vehicle is arranged with markers for determination of position and orientation of the first vehicle relative the second vehicle.
In addition, the second vehicle may be arranged with a first marker and a second marker arranged at a predetermined distance in a first plane and a third marker is arranged at a predetermined distance from the first plane.
Furthermore, the first vehicle may further comprise an absolute positioning sensor, such as a GPS-sensor, arranged to determine the absolute position of the first vehicle and wherein the position of the second vehicle relative the first vehicle is used to determine the absolute position of the second vehicle.
In an embodiment is the processor of the first vehicle arranged to store the absolute position of the second vehicle relative the first vehicle in order to document the process quality of a material fed from the first vehicle.
The second vehicle may be a machine vehicle working in cooperation with the first vehicle which may also be a machine vehicle.
In an embodiment the arrangement may comprise a plurality of second vehicles, wherein each second vehicle is provided with a fourth unique marker so as to differentiate the second vehicles from each other.
The invention further relates to a method for determining a position of a second vehicle relative a first vehicle comprising the steps of, recording at least an image of a field of view wherein the second vehicle is positioned within the field of view using an optical device mounted on the first vehicle, and processing image data in a processor to determine position of the second vehicle relative the first vehicle by performing measurements of at least one marker arranged on the second vehicle in the image.
Furthermore, the processing step may further determine an orientation of the second vehicle relative the first vehicle based on the measurements performed on three markers arranged at a predetermined distance relative each other on the second vehicle.
A method for determining the absolute position of a second vehicle, wherein the method comprises the steps of, determining the absolute position of a first vehicle using sensors mounted on the first vehicle; and determining the absolute position of the second vehicle using data from the method for determining the position of the second vehicle relative the first vehicle according to the above and data from the step of determining the absolute position of the first vehicle.
In addition, the invention relates to a method for recording events in a predetermined position comprising the steps of; determining a position of a second vehicle according to a method above, determining each point in time when the second vehicle passes the predetermined position, recording each passage of the predetermined position as an event, and determining the number of events recorded during a predetermined time interval.
In an embodiment the method further comprises a step of determining the predetermined position as the absolute position of the first vehicle at a given point in time using sensors mounted on the first vehicle.
In addition, a time record may be associated to each event.
In an embodiment the first and the second vehicle are machine vehicles cooperating during an asphalting process.
In an embodiment the method is used to form a line ahead formation of the first and the second vehicle.
In an embodiment the first and the second vehicle are unmanned aerial vehicles.
In an embodiment the method is used during refueling of aerial vehicles.
The invention provides a positioning system that can be used in a number of applications, where relative positioning of vehicles is of interest to a low cost.
Furthermore, the positioning shows good availability and accuracy regarding relative positioning of the vehicles independent of the ability to receive absolute positioning.
As in an embodiment of the invention, by documenting how the roller vehicle moves may the quality of the compacting process be documented and this information may also be used, feeding the information back to an operator and a higher quality of the asphalt may be achieved.
The invention, together with further objectives and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
Referring to
In the embodiment the robust absolute positioning system 4 of the main vehicle is arranged on the main vehicle 10 and further comprises software for the integrated sensor/s, and an absolute positioning system 40 with a reduced availability, for example, Global Navigation Satellite System (GNSS), radio navigation system or the like, and inertial sensors 50 with high availability, such as Gyros, velocity, acceleration sensors or the like. When the absolute positioning system 40 drops/fails the inertial sensors 50 will aid the navigation software arranged in a processor 60 with information in order to calculate, not connected to the positioning system, the position of the main vehicle 10 in a system of coordinates. The inertial sensors 50 may be a gyro providing direction information and a velocity sensor in order to calculate the position. It should be noted that the absolute positioning system is optional.
The relative positioning system 2 is mounted on the main vehicle 10 and comprises optical equipment 30, for example, cameras or the like, and software that calculates position of each vehicle being in the field of view of the optical equipment, arranged on a processor 60. The vehicle 20 is equipped with indication markers or the like mounted on the rollers. An example is disclosed in
There are a number of possible arrangements to aid the determination of the position and, if desired, direction of the vehicle in sight, such as, markers mounted on rollers; lightning arranged on the main vehicle and reflexes mounted on the vehicle in sight, light sources mounted on the vehicle/s in sight, three dimensional modelling of the vehicle in sight in software and correlation calculations, and the like.
In the illustrated embodiment the markers are identified by different patterns, such as the black rings on the markers are differently positioned. As stated, by identifying the marker placed backwardly relative the positions of the two front markers the orientation of the roller may be determined. When this orientation is determined the sideways distance between the markers is used to determine the distance between the main vehicle and the vehicle in sight. In an embodiment the markers are not differentiated in design since the cooperating vehicle in sight is always moving with the front facing the asphalt layer, thereby resulting in that the image processing system will always know the identity of the markers 201-203, always being positioned and uniquely identified in the image as a left, middle and right marker.
It should be noted in the embodiment of the black and white fields of the different markers, the markers may be differentiated by merely turning the patterns of the markers an angle to differentiate the markers from each other.
The position and orientation may also be used when the vehicle in sight is a roller vehicle that is provided with a plurality of roller drums mounted, for example, back and front on the roller vehicle. In this type of embodiment the front roller drum may be displaced sideways by providing an articulation point at the centre of the roller vehicle. The back drum is merely marked up with a marker, whereas in order to achieve the same result using GPS system additional GPS equipment has to be used mounted positioning the back roller drum.
It should be understood that a marker may be of any kind such as, prism, infra red diode, any visual marker, or the like.
In an embodiment the direction in the absolute system is determined from the image since it is fixedly mounted in a calibrated direction relative the navigation system of the main vehicle. In this embodiment the main vehicle is positioned in an absolute positioning system, for example, GPS or the like, and the vehicles in sight will also be able to be positioned in this system due to the relative positioning process.
One advantage of this type of system is that all sensors are mounted on one vehicle/machine. The relative positioning system will also function when the satellite signal is blocked positioning vehicles in sight of the optical equipment in the absolute system. In the embodiment wherein an integrated navigation system is mounted on an asphalt layer the availability of the system is high. The integrated navigations system may be gyro, accelerometers, inclinometers, barometers, altimeters, mechanical distance wheel, or non-contact distance camera, and/or other distance and direction sensitive means. In an absolute positioning system the coordinates of an area that has been missed is easily presented to a roller vehicle in order to correct and process the missed area.
The optical means to record the image of the vehicle in sight may be performed by a single camera or a plurality of cameras such as a close up camera and a camera used at longer distances with, for example, different resolutions. Different types of cameras may be used, such as, analogue, fire wire, IP cameras, USB, or the like.
The positioning system may be embodied merely calculating the distance to the vehicle in sight. However, by adding the orientation the result is more accurate and the result is more satisfying.
The data from the mounted image recording means is processed locally at the asphalt layer.
The system may document that the compacting process has been preformed a number of times during a certain time and is used when determining the quality of the asphalt process. In an example of the presentation of an asphalting process a computer program may present the asphalt process and the number of times an area has been rolled over by a roller by indicating the area in different colours indicating the number of times.
In an embodiment the resulting data such as number of times as well as positioning data of the roller may be presented to the vehicle in the field of view of the optical equipment. The feedback data may be used to inform the operator of the vehicle in the field of view of the camera equipment where areas been missed/clear, that the vehicle is in a right position, and/or the like. The feedback data may be transferred by using a radio data link, such as WLAN or the like. It should also be noted that the information may be used to control vehicles in the field of view in an automated system wherein the vehicle is unmanned.
In step 306 an image recording arrangement, such as a camera or the like, records an image of an area behind the surfacing machine. It should be understood that the camera in a different embodiment may be mounted on a vehicle recording an image of an area ahead of the vehicle. It should also be understood that the number of optical sensors may vary in order to increase the field of view or to improve the resolution of the images. It should also be understood that the recording apparatus may record still images, moving images, temperature images and/or the like and any combination thereof.
In step 308 the recorded image is transferred to a processor arranged in an electrical system of the surfacing machine, such as an asphalt layer, and the image is processed in the processor resulting in a number of positioning parameters, such as number of pixels, horizontally and vertically, between markers arranged on the roller for example as described in
In step 310 the parameters from the image processing are used in determining the position of the roller within the field of view relative the surfacing machine. In an embodiment the orientation of the roller is also determined. The camera is to be calibrated with the lens system, wherein a number of parameters are determined. This enables the possibility of precise calculations.
In
In step 302 the absolute position of a main vehicle, such as an asphalt layer, working in an environment wherein no interference/obstruction of GNSS signals exist, is continuously determined via a GNSS sensor, such as a GPS sensor, mounted on the asphalt layer. It should here be noted that any type of satellite positioning system may be used and the positioning sensor may be mounted at various places on the machine.
However, when the asphalt layer moves into a tunnel or the like the connection to the GPS system or the like is interrupted. In step 304 the positioning system of the machine uses the readings from distance sensors, such as a distance wheel, a non-contact velocity sensor or the like, determining the distance the machine has traveled since connection to the GPS system was interrupted and direction sensors such as Gyros, determining the direction of the machine. These readings are used to determine the position of the asphalt layer in the tunnel during operation of the vehicle.
In step 306 an optical sensor record an image of the field of view of the optical equipment.
In step 308 the recorded image is transferred to a processor arranged in an electrical system of the main vehicle, in the example, the asphalt layer, and the image is processed in the processor resulting in a number of positioning parameters, such as number of pixels, horizontally and vertically, between markers arranged on the roller for example as described in
In step 310 the parameters from the image processing are used in determining the position of the roller within the field of view relative the asphalt layer. The parameters may also be used in order to determine the orientation of the roller. The camera is to be calibrated with the lens system, wherein a number of parameters are determined, such as a relationship between a certain pixel to a certain angle to the object. This enables the possibility for using the image for precise calculations.
In step 312 the determined position is in conjunction with the absolute positioning data in the absolute system of coordinates, determined from the GPS and inertial sensors at step 302, used to determine position of the vehicle in the field of view of the optical sensor in the absolute system of coordinates. It should be noted that the system may also position a plurality of rollers within the field of view, wherein the markers of the different vehicles may be differentiated by different patterns or the like.
In
The present solution provides a way of determining the position of vehicles, such as rollers or the like, relative a main vehicle that is cheap and reliable. The system requires merely an optical sensor mounted on the main vehicle and software determining positioning parameters of the vehicles within the field of view of the optical sensor. In an embodiment the vehicles are provided with markers in order to establish positioning parameters. The invention provides a solution wherein the number of positioning sensors is reduced.
It should also be understood that the relative positioning system may be mounted on a vehicle positioned rear of a main vehicle displaying the relative positioning information to the operator of the vehicle and may also be used in order to transmit the information to the main vehicle. Additionally, the vehicle moving behind the main vehicle may comprise an absolute positioning system.
The relative positioning system may position/orientate a number of working machines, such as rollers or other working machines, wherein the rollers have markers that are keyed in a way that makes it possible to differentiate the different vehicles.
The system may also be used for vehicles travelling in a line ahead formation, air fuelling of an aircraft or the like.
The foregoing has described the principles, preferred embodiments and modes of operation of the present invention. However, the invention should be regarded as illustrative rather than restrictive, and not as being limited to the particular embodiments discussed above. It should therefore be appreciated that variations may be made in those embodiments by those skilled in the art without departing from the scope of the present invention as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 07119596.0 | Oct 2007 | EP | regional |
