WO2004026538A1

WO2004026538A1 - Method and device for automatic motion of a work vehicle

Info

Publication number: WO2004026538A1
Application number: PCT/SE2003/000136
Authority: WO
Inventors: Ulf Wilkenson
Original assignee: Wilkenson Scoop Ab
Priority date: 2002-09-20
Filing date: 2003-01-28
Publication date: 2004-04-01
Also published as: AU2003206538A1

Abstract

The present invention relates to a method for making a work machine automatically perform work tasks, which work machine comprises a positioning equipment connected to a control and monitoring computer and capable of detecting the current position of the vehicle, control and sensor means connected to the steering and drive members of the vehicle as well as connected to the control and monitoring computer and capable of controlling and detecting the steering and drive members of the vehicle. The invention is characterised by the steps of performing the current work task by an operator of the vehicle during simultaneous recording and storage in the control and monitoring computer of information from the positioning equipment as well as the sensor means, performing the current work task based on the stored information in the order it was stored during activation of the steering means. The invention also comprises a device and a computer program for performing the method.

Description

METHOD AND DEVICE FOR AUTOMATIC MOTION OF WORK VEHICLE

FIELD OF THE INVENTION

The present invention relates to a method and device for enabling automatic motion and control of work vehicles, and in particular automatic activation and control of the work units of the work vehicle during automatic motion.

BACKGROUND OF THE INVENTION The present invention relates to work vehicles such as lawn mowers, irrigating vehicles, farming vehicles, snow throwers, trucks and snow grooming machines where the same movements and work tasks are performed and repeated each time the machine is used. These types of vehicles and their work tasks could be performed unmanned, ie without an operator in the vehicle. It would have the advantage that many operations could be performed during night without the need for having personnel working night shifts and that boring and monotonous work tasks are avoided.

Up to now, no feasible technology has been presented that provides the accuracy in determining position needed to reasonable costs, and that for different positions be able to automatically operate the work units.

Document US 5,974,348 discloses a system for performing automatic work operations. It comprises self-navigating robots periodically determining its position and orientation by a navigation determination. At least seven navigation beacons are positioned around a perimeter of for example a garden work area or a field. Each beacon comprises means for emitting or reflecting electromagnetic radiation and the robot is provided with an image collector detecting the beams, by which the position of the robot may be calculated. For operating the robot a work plan is edited beforehand, including eg. the layout of the area to be worked, robot control functions, type of toll used and control instructions for operating each tool.

There are several drawbacks with the above mentioned system. A large number of beacons have to be placed around the area to be worked and each beacon has to be provided with power in order to emit radiation. The area to be worked has to be measured so that a detailed "map" is obtained, which map is then used for planning the work. Further, the pre-editing provides for errors to be made easily. There is a pronounced risk that one or several steps in the work plan are wrongly made because the programmer thinks wrongly or that position data are wrong.

Such errors may not be detected until the robot is run for the first time according to the work plan. On the one hand the work plan has to be corrected and on the other hand the first operation may result in that the robot runs into obstacles and becomes damaged or damages other objects such as crops or the like.

SHORT DESCRIPTION OF THE INVENTION

The aim with the present invention is to provide a method and a system for automatically driving machines and automatically performing different work tasks with a simplified manner of programming and performing the movements and work tasks that the machine shall perform.

This aim is obtained according to what characterises patent claim 1 and 8.

Further preferable embodiments of the invention are characterised by the dependent claims. According to a main aspect of the invention it comprises a method for enabling a work machine to automatically perform different work tasks, which work machine comprises a positioning equipment connected to a control and monitoring computer and capable of detecting the current position of the vehicle, control and sensor means connected to the steering and driving members of the vehicle and connected to the control and monitoring computer and capable of controlling and detecting the steering and driving members of the vehicle, characterised by the steps of performing the current work task by an operator during simultaneous collection and storage in the control and monitoring computer of information from the positioning equipment and the sensor means, and thereafter perform the current work task corresponding to the stored information and the order in which they are stored during activation of the steering members.

According to another aspect of the invention it is characterised by the step of, during performing the work task corresponding to the stored information, continuously detecting the current position and comparing this with the stored position information and to, if deviations are present between detected and stored position, correct the position.

According to yet an aspect of the invention the vehicle is further provided with tool control and sensor means connected to the tool to be used during the work task and connected to the control and monitoring computer and capable of controlling and detecting the tools, whereby the method performs the current work task by an operator of the vehicle during simultaneous collection in the control and monitoring computer of information from the tool sensor means, and to perform the current work task from the stored information in the order in which it is stored during activation of the tool control means at the corresponding position. The advantages with the present invention in relation to the state of the art are several.

Due to that the information regarding the position of the vehicle and its steering and drive members, and in appropriate cases the activation and the manoeuvring of the tools, are collected during "real" conditions, ie. during the performing of a work task, very secure values of the information are obtained in a simple way. These values are thus not dependent on earlier measures of the area, which may partly be erroneous, or changes of the terrain that have occurred after the measurements. It is thus to a large extent avoided the programming and editing work which needs to be performed with the technology of the state of the art, which facilitates for users of the present invention. These do thus not need to have a deeper knowledge of computers in order to create an automatized work task.

For farming, the farming machines may be manufactured smaller and lighter, because they may be running day and night without manning. This means cost reductions in the form of saved labour and cheaper equipment. One person may serve several machines at the same time and the precision be increased, ie. less damaged crops. The method enables an automatic return and refilling of fertilizers, seed, water, chemicals, etc. The rationalization effect can be substantial.

Regarding parks, golf courses etc. mowing, irrigation, spraying etc. can be performed unmanned day and night and the same person may serve several machines at the same time. With reflex points close to the mowing, it can be performed with a precision down to centimetres. If the equipment is also provided with means for detecting the golf flags, such as laser detectors, the flags may be automatically lifted out during the mowing and thereafter replaced. The coding of the computer to a certain console means that the vehicles are not liable to be stolen. For larger garden areas mowing, irrigation etc. can be performed automatically and at programmed points of time.

The method can also reduce costs for snow grooming, ice scraping, ball picking on driving ranges and irrigation of arenas and other operations where vehicles perform the same operations.

In short, there are a large number of applications where the present invention in a simple and efficient way can automatize work tasks for work vehicles .

Further advantages with the present invention and aspects of the same will become apparent from the detailed description and the accompanying drawings.

SHORT DESCRIPTION OF THE DRAWINGS

In the following detailed description of the present invention reference will be made to the accompanying drawings, whereby

Fig. 1 is a schematic view of an area to be worked with a work vehicle,

Fig. 2 shows a positioning equipment intended to be a part of the system according to the invention,

Fig. 3 shows an example of a work vehicle intended to be used in the system according to the invention,

Fig. 4 shows schematically a combination of the steering and control means included in the example of Fig. 3, and

Fig. 5 shows a block diagram over the steps performed with the method according to the invention. DETAILED DESCRIPTION OF THE INVENTION The system according to the invention comprises in general a work vehicle 10, Fig. 1 and 3, such as for example a lawn mower, farming vehicle, snow grooming vehicle, truck, or the like which performs repetitive work tasks within a certain work area 12, Fig. 1, such as for example a golf course. The vehicle is arranged with a control and monitoring computer, sensors and control devices for affecting the steering, speed, manoeuvring of tools and the like, which will be explained in detail below. The system also comprises a number of fixed points 14 placed around the area within which the vehicle shall work, Fig. 1.

In order for the system to work properly a position and direction calculation of the vehicle down to 10 centimetres and 1 / 10 degree respectively is required. The methods that are primarily seen as usable are for example 1) GSM and follow up satellite positioning system and 2) to establish the position via laser against fixedly positioned reflection points. With the present technology laser positioning is the simplest and most reliable, which will be described in more detail in connection with an embodiment.

In Fig. 2 a positioning equipment 15 is shown, intended to be fixedly attached to the vehicle. The equipment comprises a column 16 which is attached to the vehicle and a bottom part 18 attached to the column, which bottom part is formed as a part of a sphere. A corresponding spherical cradle 20 is placed in the bottom part where carriages with roller bearings 22 are arranged between these parts in order to admit a movement of the cradle in relation to the bottom part. The desired effect may also be obtained by a cardanic suspension of the equipment. In the cradle an electric motor 24 is arranged. To its output shaft 26 a wheel with a great weight is attached, which during rotation provides a gyro and flywheel effect. Because the point of gravity for the drive motor and gyro is lower than the horizontal diameter of the sphere, the gyro assumes a horizontal position when it is standing still.

The shaft of the wheel is tubular and in this a laser diode 30 and a light sensitive diode 32 are placed directed upwards through the shaft. Electrical connections (not shown) are arranged between the motor as well as the laser diode and a power source. The light sensitive diode is connected to the control and monitoring computer of the vehicle 42, Fig. 4.

In the shaft piano-lenses or concave /convex mirrors or prisms 34 are placed (rotating with the shaft), which optically spreads the laser beam 35 from the laser diode to a line. The lenses/ mirrors are arranged such that the distance to each other can be adjusted, whereby the spreading of the laser beams can be adjusted, and thereby can be set for differently broken ground. A prism 36 is placed at the end of the shaft, which refracts the beam essentially 90°. In order to protect the equipment a transparent hood 38 is arranged on top of the bottom part.

For the laser system vertical reflexes are placed on pipes, posts, trees, buildings in such a way that the vehicle has free access to at least three reflexes wherever it is positioned during operation. The placing should be irregular. Where the reflexes are placed does not have to be registered on a map or in any other way. The attachment of the reflexes shall be such that they always are in the same point.

The positioning device is further arranged with a diode 32 next to the laser sensor in order to detect the reflexes in the direction of the laser beam. A further fixed diode 40 is arranged in the transparent hood directed against the laser beam. It establishes a zero point for each revolution in relation to the reflexes (and thereby between the reflexes and the direction of the vehicle) . The measuring is very simple, by taking the time between the reflexes and by putting these in relation to the reading of the zero point of the fixed diode the degree can be set to 1 / 1000 degree and better. The laser emits a pulsed light beam that hits the reflecting surface. The reflecting light is registered with the help of an optical system and a detector mounted at a fixed distance from the laser. The optical system displays the laser dot on the surface of the detector and thereby the direction of the reflected light beam hitting the detector is determined. The distance to the laser point is determined by a geometrical calculation.

The character of the reflexes are checked when read, in order to avoid erroneous readings of temporary reflexes, sun-light etc. In broken terrain longer vertical laser lines are required, which in turn means weaker laser signals. This implies that the distance to the reflex points must be shorter than during operations on flat terrain.

The vehicle is further arranged with steering and control means and sensors for different parts of the vehicle as well as tools, which steering and control means are connected to the control and monitoring computer 42, Fig. 4. In the figure connections for incoming signals are drawn as dashed lines while connections for outgoing signals are drawn as dashed and dotted lines. As an example of vehicle and its tools is a ridable lawn mower, Fig. 3 and 4. As steering means some sort of member is needed in order to change the driving direction. This may for example be a hydraulic valve 44 which affects the oil flow from a hydraulic oil source (hydraulic tank 46 and hydraulic pump 48) to a hydraulic cylinder 50, an electric motor 46, Fig. 3, with a suitable transmission or the like, which affect the steering as well as sensors for detection of the position of the piston in relation to the cylinder or the angular position of the motor. Further control means are needed for altering the speed of the vehicle and in appropriate cases also to reverse the vehicle, such as a hydraulic valve 52. The lawn mower may also be arranged with connectable and dis- connectable cutting units and devices for lifting and lowering of the cutting units, such as a hydraulic cylinder 54 manoeuvred by a hydraulic valve 56.

The control and monitoring computer 42 is arranged with means for on the one hand obtaining signals from different sensors and signals from the positioning system as well as means for sending signals to the different control means in order to activate these. Further the control and monitoring computer is arranged with one or more processors, memory units for storing the control and monitoring programs as well as signals from different sensors. A console 58 is also connected to the computer for an operator to input data and/ or control the computer and the vehicle as well as a display in order to obtain visual information regarding the system.

The console may also advantageously be remote with radio control. How this is realised is known to the person skilled in the art within steering and control engineering and will not be described in detail.

Below it is described the collecting and use of information in order to obtain an automatic operation of a work vehicle in connection with Fig. 5. When the vehicle shall perform a specific work task for the first time it is placed at a certain starting point and in a certain direction. This starting point and direction is always the same when the specific work task is to be performed automatically. The vehicle is preferably controlled by an operator on the vehicle via the console against the processor, which in turn via ports controls the different controls of the vehicle. The console is preferably coded against a specific computer which makes it impossible to programme the computer without the specific console, which minimises the risk of theft of the vehicle. The recording is started and the vehicle is brought forward wherein the positioning equipment shows in which angles the reflection points are placed. The frequency for the reading of positions is dependent on the rotational speed of the laser, which in turn is set to a speed suitable for the modulation frequency and/ or the strength of the reflected light. The registration is done preferably 10 times per second or more frequently. The speed of the vehicle or occasional stops have no influence.

At the same time information is collected from the different sensors. Such as with the example with a lawn mower, the operator activates the mowing unit and lowers it at a certain position where the mowing is to begin. These control measures are then stored together with the position during the recording. In this way the operator performs the work task which is subsequently to be performed automatically while the changes of the direction of the vehicle and changes of the work units are recorded and stored.

As an optional additional step editing may be performed. A recorded program can be loaded into an editing program for an ordinary personal computer, which calculates and plots the movement of the vehicle, positions, directions and thereby the worked surface and creates thereby a map over the area which can be shown on the screen or be printed. The positions of the reflex points are calculated and plotted on the map.

Way-points can be plotted where the vehicle temporarily shall be stopped and other operations are performed. With a click on the route all controls are controlled in this position. The controls may be set, routes redirected etc. with this program. Different programs can also be joined together so that for example different fields can be worked after each other, with programs added for transport between the fields. The result is a new program that can be used for performing a work task. Calculation and planning of the route can also be done automatically taking into consideration that the vehicle carries other tools. With data from the recording and information regarding the character of the tool in relation to the steering and following wheels of the vehicle, all positions of obstacles can be determined, and these can be taken into consideration with other tools and other driving directions.

The editing program may contain a set of different tool for a certain type of vehicle that can be used for the same route. For example if a vehicle is to perform different work tasks on the same area, such as for example mowing, irrigation, spreading of fertilizers etc. on a golf course, it is not necessary to record the route for every work task. It suffices to record the route once and then in the editing program use the recorded route and add different tools that are to be used indicating in the edited program at which positions the tool is to be activated.

It is also possible to just record the positions of the outer boundaries of a work area, if the area does not contain any obstacles, and then to lay out the route within the area so that the area is covered, taking into account the range that the specific toll is covering.

With a loaded program the vehicle is started from the starting point of the program, for example with a timer or with a remote control which for security reasons require that persons are at a certain distance from the vehicle. The computer of the vehicle starts with determining the position and direction of the vehicle against the reflex points of the surrounding. If these do not match regarding number and relation to each other a signal is given that the program cannot be run from this point. Now the computer performs all the changes of controls and steering that the program contains, in the order they were recorded or according to the program that was created during the above editing process. During the running position and direction checks, these are compared with the recorded values. If deviations occur due to deviating speed in comparison with the recording instant, the recording frequency is adapted to the measured positions.

The steering is primarily performed according to the recorded values. When a deflection occurs from the recorded route, this is adjusted with the steering control. If the vehicle is to perform critical controls settings (for example forward/ reverse or larger turns) or changes of the setting of the tools, it is checked that sufficient position control has been done within the desired margin. If that is not the case, the vehicle is stopped for a determination of the position and correction before the operation is performed. This is especially true when the frequency of the position determination is lower than the frequency of the recorded data.

If reflex points that were present during the recording cannot be detected, the vehicle continues to drive as long as there are sufficient number of other readable points in order to ensure the position.

If the vehicle has a large deflection (which normally only occur during skidding) the program should be able to automatically stop, lift the tools, reverse to a known performed position, lower the tools and repeat the operation at a low speed (in order to obtain a sufficiently high frequency of the position determination).

The vehicle shall be equipped with sensing means , such as for example a pressure-sensitive bar 80 or a light source 82 emitting a light beam detected by a sensor, which stops the vehicle immediately when hitting an object or when the light beam is interrupted. The function of this means may be switched off during recording. If the vehicle during recording at some point hits an object, this is registered so that the corresponding hit in exactly the same position is tolerated during playback.

In addition to this the vehicle may be arranged with a laser 84 capable of measuring the distances to all objects in the driving direction. These can be added during recording so that during playback a comparison is made with the values during recording, so that the vehicle cannot get stuck by fixed objects that it is programmed to pass around (for example trees, buildings, rocks etc.).

It shall be understood that the embodiment described above and shown in the drawings is to be regarded only as a non-limiting example of the invention and that its scope of protection is defined by the patent claims.

Claims

PATENT CLAIMS

1. A method for making a work machine automatically perform work tasks, which work machine comprises a positioning equipment connected to a control and monitoring computer and capable of detecting the current position of the vehicle, control and sensor means connected to the steering and drive members of the vehicle as well as connected to the control and monitoring computer and capable of controlling and detecting the steering and drive members of the vehicle, characterised in the steps of : - performing the current work task by an operator of the vehicle during simultaneous recording and storage in the control and monitoring computer of information from the positioning equipment as well as the sensor means, - performing the current work task based on the stored information in the order it was stored during activation of the steering member.

2. Method according to claim 1, characterised by the step, during performing the work task based on the stored information, continuously detecting the current position and comparing this to stored position information.

3. Method according to claims 2, characterised in that, if deviations occur between detected and stored position, correcting the position with the aid of the steering means of the vehicle.

4. Method according to claim 3, characterised in that, if the correction does not provide a concordance between measured and stored information, bringing back the work vehicle to an earlier position where concordance has been obtained, and continue the work task from that position.

5. Method according to any of the previous claims, whereby the vehicle further is provided with tool control and sensor means connected to the work tools to be used during the work task as well as connected to the control and monitoring computer and capable of controlling and sensing the work tools, characterised by performing the current work task by an operator of the vehicle during simultaneous collection and storage in the control and monitoring computer of information from the tool sensor means, - performing the current work task based on the stored information in the order they have been stored during activation of the tool control means at the corresponding position.

6. method according to claim 5, characterised in that the stored information from the tool sensor means are linked to the current stored position.

7. Method according to any of the preceding claims, characterised by the step of editing the recorded and stored information.

8. Device for enabling a work machine to automatically perform work tasks, comprising a positioning equipment connected to a control and monitoring computer and capable of detecting the current position of the vehicle, control and sensor means connected to the steering and drive members of the vehicle as well as connected to the control and monitoring computer and capable of controlling and sensing the steering and drive members of the vehicle, characterised by means for collecting and storing in the control and monitoring computer of information from the positioning equipment as well as the sensor means during the performing of the current work task by an operator of the vehicle and means for performing the current work task based on the stored information in the order it was stored during activation of the steering member.

. Device according to claim 8, characterised in that it further comprises tool control and sensor means connected to the work tools to be used during the work task and capable of controlling and detecting the work tools as well as means for collecting and storing in the control and monitoring computer of information from the tool sensor means during the performing of the current work task by an operator, and means for performing the current work task based on the stored information in the order it was stored during activation of the tool control means at the corresponding position.

10. Device according to any of the claims 8-9, characterised in that it further comprises means capable of detecting obstacles that the vehicle hits during the performing of the current work task based on the stored information.

11. Device according to any of the claims 8-10, characterised in that it further comprises means for detecting and determining distance to obstacles in its route.

12. Device according to any of the claims 8- 11, characterised in that the positioning equipment comprises a light source capable of emitting a light beam, means for rotating the light beam 360° in substantially horizontal direction, a plurality of reflectors arranged in connection to the area that the work task shall be performed as well as a detector capable of detecting the reflected light.

13. Data program product comprising computer code means and/ or software code parts for making a computer perform the steps according to any of the claims 1-7.