JPH08249061A - Running controller for autonomous running vehicle - Google Patents

Abstract

PURPOSE: To improve the control stability by adaptively switching the correction of a position measurement data in accordance with the distance or movement at the time or correcting the position measurement data based on the running history from a reference position by position measurement data using a satellite to control the autonomous running. CONSTITUTION: The difference between position measurement data from a D-GPS position detection part 53 and that from a dead reckoning position detection part 52 at the time corresponding to the time of D-GPS position measurement is calculated as a mutual position correction value, and its moving average is obtained. When the distance of movement to a target point exceeds a preliminarily set threshold, the latest averaged position correction value is added to position measurement data from the dead reckoning position detection part 52 to obtain the present position; but when it is shorter than the threshold, position measurement data from the part 52 is directly used to obtain the present position; and thus, it is stopped to correct the position measurement data of dead reckoning by position measurement data of D-GPS in the case that the distance of movement is so very short that it is difficult to cope with the distance by the position measurement precision of D-GPS, thereby improving the control stability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling control apparatus for an autonomous traveling vehicle which receives radio waves from a satellite to measure the self position of the vehicle and controls the autonomous traveling.

[0002]

2. Description of the Related Art Generally, in an autonomous vehicle such as a work vehicle that performs unmanned work such as grass cutting and lawn mowing in various fields such as a golf course, a river bank, a park, etc., the technology for measuring the self position makes autonomous driving. It becomes important above, and as a technique for measuring this self-position, there is a conventional technique disclosed in Japanese Patent Laid-Open No. 63-2
As disclosed in Japanese Patent Publication No. 47612 and the like, a technique of receiving a radio wave transmitted from a positioning satellite to measure its own position, and as disclosed in Japanese Patent Application Laid-Open No. Hei 2-132321, There is a dead reckoning technology that estimates the position of a vehicle from the direction of travel.

However, in the former technique, due to the error of the clock of the satellite and the receiver, the error of the orbit of the satellite, the delay of the radio wave due to the ionosphere, the delay of the radio wave due to the atmosphere, multipath, etc. Positioning accuracy is insufficient for moving autonomous work vehicles, and in the latter technique, errors accumulate in proportion to the traveled distance.

Therefore, the applicant of the present invention has previously filed Japanese Patent Application No. 6-
In No. 19642, positioning information from a satellite is received at a known point, and correction information based on the positioning result is transmitted.
By providing the autonomous traveling vehicle with the second satellite-based positioning means for receiving the correction information from the satellite-based positioning means and positioning the vehicle's own position based on the correction information and the positioning information from the satellite, The dead-reckoning positioning means that secures far better accuracy than the use positioning means, calculates the travel history from the reference position, and positions the vehicle based on this travel history is provided. Averaging processing is performed on the difference between the positioning data at the corresponding times of the second satellite-based positioning means and the dead-reckoning positioning means regardless of whether the vehicle is running or stopped. By correcting the positioning data by the dead-reckoning positioning means with the latest position correction value, the positioning data by dead-reckoning navigation is always accurately corrected by the positioning data from the satellite, and efficient and highly accurate autonomous operation is possible. It has proposed a technique capable of performing a row.

[0005]

However, for example, when an unmanned work vehicle for mowing, lawn mowing, or the like continues to work by turning or translating in the vicinity of the boundary of the work area, autonomous operation at an extremely short distance is required. If the applicant proposes to apply the technique previously proposed during traveling, there is a limit to the accuracy of positioning data using satellites, which may cause unstable control.

The present invention has been made in view of the above circumstances, and when the autonomous traveling is controlled by correcting the positioning data based on the traveling history from the reference position by the positioning data using the satellite, the positioning data is determined according to the moving distance. It is an object of the present invention to provide a traveling control device for an autonomous vehicle capable of adaptively switching the correction of (1) to improve control stability.

[0007]

The present invention receives correction information from a first satellite-based positioning means that receives positioning information from a satellite at a known point and transmits correction information based on the positioning result, A second satellite-based positioning means for positioning the position of the vehicle based on the correction information and the positioning information from the satellite;
Dead reckoning positioning means for calculating a traveling history from the reference position and positioning the position of the vehicle based on the traveling history, and the second satellite regardless of whether the vehicle is traveling or stopped. The difference between both positioning data at corresponding times of the use positioning means and the dead reckoning positioning means is calculated as a position correction value, and the mutual correction value calculating means for moving average processing and the positioning data of the dead reckoning positioning means are used. The moving distance from the current position of the vehicle to the target position is compared with a set value, and when the moving distance is equal to or less than the set value, autonomous traveling is controlled based on the positioning data of the dead reckoning positioning means, and the moving is performed. When the distance exceeds the set value, the current position of the vehicle is newly calculated by correcting the positioning data by the dead reckoning positioning means with the latest position correction value averaged by the mutual correction value calculating means, Characterized by comprising a self-running control means for controlling the law travel.

[0008]

In the present invention, the second satellite-based positioning means receives the positioning information from the satellite and the correction information based on the positioning result at the known point from the first satellite-based positioning means and receives the vehicle position. In addition to measuring, the dead reckoning positioning means calculates the travel history from the reference position, measures the vehicle position based on this travel history, and determines whether the vehicle is running or stopped. Regardless, the difference between both corresponding positioning data of the second satellite-based positioning means and dead-reckoning positioning means is calculated as a position correction value and averaged. Then, the autonomous traveling control means compares the moving distance from the current position of the vehicle to the target position based on the positioning data of the dead reckoning positioning means with a set value, and when the moving distance is less than the set value, the dead reckoning positioning means Autonomous driving is controlled based on the positioning data of the vehicle, and when the travel distance exceeds the set value, the positioning data by the dead reckoning positioning means is corrected by the latest averaged position correction value to newly set the current position of the vehicle. Calculate and control autonomous driving.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The drawings show an embodiment of the present invention, FIG. 1 is a block diagram of a control device, FIG. 2 is an explanatory view showing a lawn mowing vehicle equipped with a D-GPS mobile station and a D-GPS fixed station, and FIG. FIG. 4 is an explanatory view showing the structure of the cut boundary detection mechanism, FIG. 4 is an explanatory view showing the operation of the cut boundary detection mechanism, FIG. 5 is an explanatory view showing the structure of the steering control system, and FIG. 6 is a traveling route and a work area. Explanatory drawing, FIGS. 7 and 8 are flowcharts of the main control routine,
FIG. 9 is a flowchart of a movement traveling control routine to the work area, FIG. 10 is a flowchart of a D-GPS / dead-reckoning navigation mutual correction value calculation routine, FIG. 11 is a flowchart of a current position calculation routine, and FIG. 12 is a cut mark boundary detection routine. A flowchart, FIG. 13 is a flowchart of a D-GPS wireless communication routine.

In FIG. 2 (a), reference numeral 1 indicates an unmanned and self-propelled autonomous vehicle, and in this embodiment,
It is a lawn mowing vehicle for grass and lawn mowing work at golf courses,
The vehicle is driven by the engine and the steering angles of the front and rear wheels can be controlled independently. This lawnmower 1
Includes a satellite radio receiver for receiving radio waves from a satellite to measure its own position, a dead reckoning sensor for measuring the current position based on the travel history, a sensor for detecting a traveling obstacle, In the grass / lawn mowing work area, a sensor or the like for detecting a cut boundary for performing a contour running along the cut boundary is mounted, and highly accurate autonomous running can be performed.

In the present embodiment, the satellite radio receiver is a global positioning satellite system (Global Positioning System).
tem; hereinafter abbreviated as GPS) is a GPS receiver for receiving radio waves from GPS satellites to measure its own position, and performs position observation at a fixed station located at a known point to correct information ( So-called differential G which feeds back (differential information) to the mobile station.
Mobile station GPS for PS (hereinafter abbreviated as D-GPS)
It is a receiver.

As is well known, the factors of positioning errors by GPS include errors of satellite and receiver clocks, errors of satellite orbits, delay of radio waves by the ionosphere, delay of radio waves by the atmosphere, multipath, etc. In addition, the largest error factor is selectable availability (S / A)
There is a deliberate deterioration in accuracy called by the operator. Of the errors due to these factors, the in-phase error can be removed by using the correction information corresponding to each satellite captured by the fixed station at the known point, and the positioning accuracy at the mobile station is about several meters. Can be dramatically improved.

For this reason, the lawnmower work vehicle 1 has an antenna 2 for a mobile station GPS receiver and an antenna 3 for a wireless communication device for receiving differential information from a fixed station.
Are installed upright, and at a known point outside the vehicle, as shown in FIG. 2B, the antenna 3 of the fixed station GPS receiver is installed.
1 and a fixed station 30 equipped with an antenna 32 of a wireless communication device for transmitting differential information to a mobile station GPS receiver.

As the dead reckoning sensor, a geomagnetic sensor 4 and a wheel encoder 5 are used as the lawnmower vehicle 1.
The contactless sensors 6a and 6b such as ultrasonic sensors or optical sensors are provided as the obstacle detection sensors.
Is attached to the front and rear of the lawn mowing vehicle 1,
Contact type sensors 7a, 7b using a micro switch or the like
Are attached to the front and rear ends of the lawnmower work vehicle 1.

At the lower part of the vehicle body of the lawn mowing vehicle 1, a cutting blade mechanism 9 such as a mower for performing grass / lawn mowing work is provided.
And a cut mark boundary detection mechanism 10 for detecting a cut mark boundary of grass / lawn mowing work.

The above-mentioned cut boundary detecting mechanism 10 is constituted by arranging two sets of grass and turf height detecting mechanisms in parallel on the left and right sides of the vehicle body in parallel. The front view of FIG. As shown in the side view of FIG. 2b), each mechanism is provided on the lower end of each rocking member 12a, 12b rotatably supported by the vehicle body 1a of the lawnmower working vehicle 1 via shafts 11a, 11b. Sled-shaped plates 13a and 13b that move up and down according to the length of the grass are rotatably suspended. The rocking members 12a, 12
b is fixed to the left and right shafts 11a and 11b, respectively, and the respective rotation angles are detected by the rotation angle sensors 14a and 14b attached to the left and right shafts 11a and 11b, respectively. .

The vehicle body 1 through the swing members 12a and 12b.
The sled-shaped plates 13a and 13b suspended on a are light enough not to crush grass / turf, and when the lawn mowing vehicle 1 moves, it moves up and down according to the height of the grass / turf. The swinging members 12a and 12b rotate, and the respective rotation angles are detected by the rotation angle sensors 14a and 14b.

Further, as shown in FIG. 1, the lawnmower working vehicle 1 is equipped with a control device 50 composed of a microcomputer or the like, and sensors and actuators are connected to the control device 50. , Mobile station GP
The S receiver 15 and the wireless communication device 16 for receiving the differential information from the fixed station 30 are connected, the positioning information from the satellite is received at a known point, and the correction information based on the positioning result is transmitted. To the fixed station 30 as a satellite positioning means, a second satellite positioning means for receiving positioning information from the satellite and correction information from the fixed station 30 and positioning the vehicle Function, function as a dead reckoning positioning means for calculating the traveling history from the reference position and positioning the position of the vehicle based on this traveling history, regardless of whether the vehicle is running or stopped A function as a mutual correction value calculation means for calculating a difference between both positioning data at corresponding times of the second satellite-based positioning means and the dead reckoning positioning means as a position correction value, and averaging. The moving distance from the current vehicle position to the target position based on the positioning data of the dead reckoning positioning means is compared with a set value, and when the moving distance is less than or equal to the set value, based on the positioning data of the dead reckoning positioning means. When the moving distance exceeds the set value, the positioning data by the dead reckoning positioning means is corrected by the latest position correction value averaged by the mutual correction value calculating means to correct the own vehicle. The current position is newly calculated, and the function as the autonomous traveling control means for controlling the autonomous traveling is realized.

More specifically, the control device 50 is connected to the cut boundary detecting section 51 to which the rotation angle sensors 14a and 14b of the cut boundary detecting mechanism 10 are connected, the geomagnetic sensor 4 and the wheel encoder 5. Dead-reckoning position detecting section 52, D-GPS position detecting section 53 to which the mobile station GPS receiver 15 and the wireless communication device 16 are connected, the non-contact type sensors 6a, 6b and the contact type sensors 7a, 7
The obstacle detection unit 54 to which b is connected, and each of these detection units 5
1, 52, 53, 54 are connected to a travel control unit 56, a work data storage unit 57 in which a work data map referred to by the travel control unit 56 is stored, and a vehicle is instructed by the travel control unit 56. A vehicle control unit 58 for performing control is provided, and further, a drive control unit 59, a steering control unit 60, and a mowing unit are provided to drive the respective mechanical units of the lawnmower working vehicle 1 based on the output from the vehicle control unit 58. A blade controller 61 is provided.

The cut boundary detection unit 51 processes the rotation angle signals from the rotation angle sensors 14a and 14b of the cut boundary detection mechanism 10 according to the grass / turf heights to cut the grass / turf boundary. Detect the position. That is, in the grass / lawn mowing work area, as shown in FIGS. 4A and 4B, the rotation angle θ1 detected by one rotation angle sensor 14a and the rotation angle θ1 detected by the other rotation angle sensor 14b. When the difference from the rotation angle θ2 is a certain value or more, that position is detected as a cut boundary between the already-cut part where grass / turf has already been cut and the uncut part where grass / turf has not yet been cut, The position data of the cut boundary is output to the traveling control unit 56.

The dead reckoning position detecting unit 52 integrates the vehicle speed detected by the wheel encoder 5 to obtain a traveling distance, and accumulates the traveling distance in correspondence with a change in traveling direction detected by the geomagnetic sensor 4. By doing so, the travel history from the reference point is calculated, the current position of the vehicle is measured, and the positioning data is output to the travel control unit 56. The sensors connected to the dead reckoning position detector 52 include the geomagnetic sensor 4 and the wheel encoder 5.
The combination is not limited to the above, and a gyro or the like may be combined.

In the D-GPS position detector 53, a group of GPS satellites captured via the mobile station GPS receiver 15 (at least four in the case of three-dimensional positioning and at least three in the case of two-dimensional positioning). ) Navigation message from 70,
That is, satellite clock correction coefficient, orbit information, satellite calendar,
The position of the vehicle is measured with high accuracy based on positioning information such as satellite placement and the differential information received from the fixed station 30 via the wireless communication device 16, and the positioning data is output to the travel control unit 56. .

The fixed station 30 for the D-GPS position detector 53 is a D-to which a fixed station GPS receiver 33 is connected.
GPS fixed station section 34, D-GPS for transmitting the differential information from this D-GPS fixed station section 34
The information transmitter 35 includes a wireless communication device 36 connected to the D-GPS information transmitter 35.

In the D-GPS fixed station section 34, the satellite group 70 received via the fixed station GPS receiver 33.
And processing the positioning information from to create differential correction data. This differential correction data is
The D-GPS information transmitting unit 35 converts the packet data into wireless communication packet data and transmits the packet data via the wireless communication device 36.

In the present embodiment, the D-GPS fixed station 30 is installed as a specific device for the mobile station of the lawnmower vehicle 1, but it is a radio that transmits differential information. Existing D-GP with stations
It is also possible to use an S fixed station or an existing D-GPS fixed station that transmits differential information via a communication satellite.

On the other hand, the obstacle detecting section 54 includes the non-contact type sensors 6a, 6b and the contact type sensors 7a, 7b.
An obstacle that cannot be predicted is detected by 7b, and a detection signal is output to the traveling control unit 56.

In the traveling control unit 56, the cut boundary detection unit 51, the dead reckoning position detection unit 52, the D-GP.
Each positioning data from the S position detection unit 53 is selected and processed as appropriate, the error amount between the current position and the target position is calculated by referring to the work data of the work data storage unit 57, and the travel route and the vehicle control instruction are given. decide. When an obstacle is detected by the obstacle detection unit 54, an instruction to avoid the obstacle or stop the vehicle is issued.

The autonomous traveling control of the lawnmower work vehicle 1 is performed by correcting the dead reckoning positioning data from the dead reckoning position detecting section 52 and the dead reckoning positioning data by the D-GPS positioning data from the D-GPS position detecting section 53. Driving control by D-GPS / dead reckoning which adaptively switches between and, and traveling traveling control in a work area using the data from the above-mentioned cut boundary detection unit 51 are roughly divided into D-GPS / dead reckoning. Under the traveling control by D-GPS, when the moving distance to the target point exceeds a preset threshold value,
The dead reckoning positioning data is corrected by correcting the dead reckoning positioning data with the value obtained by averaging the difference between the positioning data and the dead reckoning positioning data, and when the moving distance to the target point is less than or equal to the above threshold, the dead reckoning positioning data is directly calculated. Use to calculate the current position.

The work data storage unit 57 is composed of a ROM area for storing fixed data and a RAM area for storing work data under control execution. The ROM area is a work for performing grass and lawn mowing work. The terrain data of the area, the terrain data of the entire area including a plurality of work areas, and the like are stored in advance. In the RAM area, data processed from signals from each sensor, positioning data by D-GPS, positioning by dead reckoning Data, mutual correction value data of D-GPS and dead reckoning described later, and current position data of the vehicle calculated based on this mutual correction value data or positioning data by dead reckoning are stored. There is.

The vehicle control unit 58 converts the instruction from the traveling control unit 56 into a specific control instruction amount and outputs it to the drive control unit 59, the steering control unit 60, and the cutting blade control unit 61. As a result, the drive control unit 59 drives the travel control actuators 20 such as the throttle actuator, the speed change actuator, the forward / reverse switching actuator, and the brake actuator for adjusting the throttle opening to control the engine output, and the hydraulic pump. 21 is controlled to generate hydraulic pressure for driving each functional unit. In the steering control unit 60, the front wheel steering hydraulic control valve 22 is operated based on the inputs from the front wheel steering angle sensor 25a and the rear wheel steering angle sensor 25b.
a, steering control (steering amount feedback control) is performed via the rear wheel steering hydraulic control valve 22b, and the cutting blade control unit 61 performs servo control of the cutting blade mechanism 9 via the cutting blade control hydraulic control valve 26. To do.

As shown in FIG. 5, the steering system of the lawnmower working vehicle 1 includes a hydraulic pump 2 driven by an engine 19.
1, the front wheel steering hydraulic control valve 22a and the rear wheel steering hydraulic control valve 22b controlled by the steering control unit 60 are connected, and the hydraulic control valves 22a and 22b are respectively connected to
Front wheel hydraulic cylinder 23a, rear wheel hydraulic cylinder 23b
Are respectively connected to each of the hydraulic cylinders 23a, 2
3b, front wheel steering mechanism 24a, rear wheel steering mechanism 24b
Are driven independently.

When the steering angles of the front and rear wheels detected by the steering angle sensors 25a and 25b attached to the steering mechanisms 24a and 24b are input to the steering control section 60, the detected steering angles are The steering control unit 60 controls the steering mechanisms 24a and 24b via the hydraulic control valves 22a and 22b so as to eliminate the deviation from the target steering angle.

Hereinafter, a case where unmanned grass / lawn mowing work is performed on a plurality of divided work areas as shown in FIG. 6 will be described. In this case, the lawnmower 1 is assumed to be waiting at an arbitrary preparation position 80 before starting work, and is moved to the first work area 82.
Lawn mowing work, movement from the work area 82 to the next work area 85, grass / lawn mowing work in this work area 85, and movement to the return position 88 are shown in the main control routine shown in FIGS. 7 and 8 and in FIG. It is carried out autonomously according to a mobile traveling control routine.

First, in the main control routine shown in FIGS. 7 and 8, in step S101, the D-GPS is used to measure the preparation position 80 which is the current self-position. This position measurement is
It is performed by converting the D-GPS positioning data such as longitude and latitude (altitude data is also added if necessary) into geodetic system data stored in the work data storage unit 57. Data conversion to this geodetic system is performed by D-GPS.
It may be performed by the position detection unit 53 or the traveling control unit 56.

Next, in step S102, the topographical data of the first work area 82 is read out by referring to the work data storage unit 57, a route 81 from the measured preparation position 80 to the work start point is generated, and step S103 is performed. Go to. Step
In S103, the traveling traveling control routine of FIG. 9 described later is executed to move the vehicle to the work start position, and in step S104, the cutting blade control hydraulic control valve 26 is opened to supply the cutting blade mechanism 9 with hydraulic pressure. Then, operate the cutting blade to start grass / lawn mowing work.
In addition, grass and lawn mowing work is performed at a constant speed (for example, 3 to 6 km).
/ H). If the traveling speed of grass / lawn mowing is too slow, the grass / lawn mowing work efficiency will deteriorate, and if it is too fast, uneven cutting will occur, so about 3 to 6 km / h is desirable.

Then, in step S105, it is checked whether or not it is the first work, and if it is the first work, the process proceeds from step S105 to step S106 to obtain the D-GPS / After the vehicle current position by dead reckoning is read from the work data storage unit 57, the work data of the work data storage unit 57 is referred to in step S107, and the route of the first work (first row) in the work area 82 Find the amount of error from the current position.

Next, the process proceeds to step S108 and the above step
The steering amount for each target steering angle of the front and rear wheels is determined according to the error amount obtained in S107, and in step S109, the front wheel steering mechanism is operated via the front wheel steering hydraulic control valve 22a and the rear wheel steering hydraulic control valve 22b. 24a and the rear wheel steering mechanism 24b are respectively driven, and the front wheel steering angle sensor 25a and the rear wheel steering angle sensor 25b detect the front wheel steering angle and the rear wheel steering angle to perform control so as to obtain the target steering angle.

Then, in step S110, one step (one column)
It is checked whether or not the end point has been reached. If the end point has not been reached, the process returns to step S106 described above to continue the grass / lawn mowing work, and when the end point is reached, one section (current section It is determined whether or not the work of the work area of the work target) is completed.

In this case, since it is the first work, the process returns from step S118 to the above-mentioned step S105 to check again whether or not it is the first work, and when it is the second work or later, the process branches from step S105 to step S111. The traveling control actuator 20 is driven to laterally shift the vehicle body by the width of the cutting blade to move it to the next work position, and in step S112 and thereafter, the contour travel of the work path 83 along the cut boundary is performed. The movement to the next work position is performed based on the vehicle position by D-GPS / dead reckoning. However, since the movement distance is extremely short, the current position calculation routine of FIG.
The current position is obtained by directly using the dead reckoning positioning data.

In step S112, a cut boundary detection routine shown in FIG. 12, which will be described later, is executed to detect the cut boundary of the previous work based on the signals from the rotation angle sensors 14a and 14b of the cut boundary detection mechanism 10. Then, step S113
Then, the margin of cut is compared with the vehicle position to obtain the error amount for realizing the preset lawn mowing overlap amount.

Then, the process proceeds to step S114, and when the steering amounts of the front and rear wheels are determined according to this error amount, step S115
The front wheel steering mechanism 24a and the rear wheel steering mechanism 2 are connected via the front wheel steering hydraulic control valve 22a and the rear wheel steering hydraulic control valve 22b.
4b are respectively driven and controlled to obtain the target rudder angle.

Then, in step S116, the current vehicle position by D-GPS / dead reckoning is read again from the work data storage unit 57, and in step S117 it is checked whether or not the one-stroke end point has been reached. If the end point has not been reached, the process returns to step S112 described above to continue the contour travel along the cut boundary, and when the end point for one stroke is reached, step S118
Then, it is determined whether or not the work for one section (work area 82) is completed.

Then, steps S105 to S118 are repeated until the work in one section (work area 82) is completed, and when the work in one section is completed, the process proceeds from step S118 to step S119 to finish all the work. Determine whether or not. Here, since the work in the next work area 85 has not been completed yet, if the process returns to step S102 described above and the path 84 from the work area 82 to the work area 85 is generated by the same procedure,
Next work area 85 according to the traveling control routine of FIG.
Similarly, the grass and lawn mowing work is performed by D-GPS and dead reckoning only for the first stroke, and the route 86 is used for the second and subsequent strokes.
Perform grass and lawn mowing work by following the running of.

Eventually, when all the work is completed, step S1
After proceeding from step S120 to step S120 and generating the route 87 to the return position 88 by referring to the work data storage unit 57, in step S121, the route is moved to the return position 88 according to the traveling control routine of FIG. Stop the vehicle.

Next, the autonomous traveling on the routes 81, 84, 87 by the traveling control routine shown in FIG. 9 will be described. In the main control routine described above, the routes 81, 84 and 87 are generated from the positioning data of the self position and the work data of the work data storage unit 57. However, the routes 81, 84 and 87 themselves are previously generated. It may be stored in the work data storage unit 57.

In the self-position measurement by D-GPS, much better accuracy can be obtained than in the case of a single GPS, but it is necessary for autonomous traveling control depending on the satellite acquisition state, the radio wave reception state, and the like. The accuracy required for timing may not be obtained. Therefore, in the present invention, regardless of whether the vehicle 1 is running or stopped, the D-G
Mutual position correction values (mutual correction values) including both PS and dead reckoning are calculated, and the positioning data by dead reckoning is corrected by this mutual correction value to ensure accuracy.

That is, in step S201, when the target point, the target trajectory, and the preset designated traveling speed stored in the work data storage unit 57 are read out, it is determined in step S202 whether or not the movement is completed, and the movement is completed. If so, the vehicle is stopped in step S203 and the routine is exited. If the movement is not ended, the process proceeds to step S204.

In step S204, the moving speed of the lawnmower working vehicle 1 detected by the wheel encoder 5 is the above-mentioned step S2.
The output of the engine 19 is controlled via the throttle actuator that constitutes one of the traveling control actuators 20 so that the specified traveling speed read out at 01 is reached, and step S2
At 05, the current position of the own vehicle obtained by the current position calculation routine of FIG. 11 to be described later is read from the work data storage unit 57, and at step S206, the target point and the current position are compared to calculate the target traveling azimuth angle. To do.

Next, when proceeding to step S207, the current traveling azimuth detected momentarily by the geomagnetic sensor 4 is read out, and at step S208, an error amount of the traveling azimuth from the target traveling azimuth and the current traveling azimuth. Is calculated, the steering amount of the front and rear wheels is determined according to the error amount, the process proceeds to step S209, and the hydraulic control valve 22 for steering the front wheels is determined according to the determined steering amount of the front and rear wheels.
The front wheel steering mechanism 24a and the rear wheel steering mechanism 24b are respectively driven via a and the rear wheel steering hydraulic control valve 22b to perform control so as to obtain the target steering angle.

Then, in step S210, the current position is compared with the target position, and the process proceeds to step S211 to determine whether or not the target position has been reached. As a result, when the target position has not been reached, the process returns to step S206, the target traveling azimuth angle is calculated again, and traveling is continued, and when the target position is reached,
Returning to step S201, the target point, the target trajectory, and the designated traveling speed are read out, and the same processing is repeated.

Now, the measurement of the current position of the vehicle will be described. When measuring the current position, the D-GPS shown in FIG.
・ D-GPS by dead reckoning mutual correction value calculation routine
・ A mutual correction value that includes both dead reckoning is calculated, and the current position calculation routine of FIG. 11 calculates the current position by dead reckoning according to the moving distance to the target point or uses the mutual correction value. Decide whether to get the current position.

First, the D-GPS / dead reckoning mutual correction value calculation routine will be described. This D-GPS / dead-reckoning navigation mutual correction value calculation routine is processed in the background by time sharing or the like so that the latest correction value can always be referred to. Waiting for the input of the positioning result Pg by the differential calculation from the GPS wireless communication routine,
-When the GPS positioning result Pg is input, the process proceeds to step S302 to read the dead reckoning position data Ps at the time corresponding to the D-GPS positioning time.

Next, in step S303, the D-GPS is used.
If the difference between the positioning result Pg by P and the position data Ps by dead reckoning is calculated as a mutual correction value (K = Pg−P
s), in step S304, the moving average value Ka of the past n points including the currently calculated mutual correction value K is calculated, and the moving average value K stored in the RAM area of the work data storage unit 57 is calculated.
a is updated, the process returns to step S301, and the next D-GPS
Wait for input of positioning result Pg. It should be noted that the value of n is determined in advance as an optimum value depending on the precision of dead reckoning and the magnitude of accumulated error.

The latest averaged mutual correction value Ka calculated in the background as described above is read into the current position calculation routine of FIG. 11, and when the moving distance to the target point is relatively long, dead reckoning navigation is performed. The current position is calculated by applying the mutual correction value Ka to the positioning data according to, and in the case of movement of an extremely short distance, the current position is calculated based on the dead reckoning positioning data.

First, in step S401, the current position data Psn by dead-reckoning is read out, and in step S402, the moving distance S to the target point is compared with a threshold value Df set in advance in consideration of the controllability of the system. , S> Df,
In step S403, the current position P is calculated by adding the latest averaged mutual correction value Ka calculated by the D-GPS / dead-reckoning mutual correction value calculation routine to the current position data Psn by dead-reckoning. The obtained data is stored in the work data storage unit 57 and the routine is exited.

That is, since the difference between the D-GPS positioning data and the dead reckoning positioning data is always obtained as a mutual correction value and accumulated and a moving average is calculated, it is temporarily changed depending on the satellite acquisition state or the radio wave reception state. Even when the positioning accuracy of the D-GPS decreases, the dead reckoning positioning data is corrected by the latest moving average mutual correction value, so that the vehicle 1 is stopped at a certain point for a predetermined time. It is possible to always accurately calculate the current position without the need to take measures such as accumulating the positioning data of (1) to improve the accuracy.

On the other hand, in the above step S402, S ≦ Df
If the moving distance to the target point is extremely short, the process branches from step S402 to step S404 and the dead reckoning current position data Ps read in step S401.
Since n is directly passed as the current position P, it is stored in the work data storage unit 57, and the routine is exited.

Current position data Psn by this dead reckoning
In the present embodiment, the situation in which is used directly without being corrected by the positioning data by D-GPS occurs when moving to the next work position in the work area (step S111 in the main control routine of FIG. 7), and D The control stability can be improved by stopping the correction of the dead reckoning positioning data by the D-GPS positioning data when the vehicle moves in an extremely short distance, which is difficult to handle with the positioning accuracy of GPS.

Next, the processing for detecting the boundary of the cut mark in the copying traveling in the grass / lawn mowing work area will be described with reference to the flowchart of FIG.

In the cut boundary detection routine of FIG. 12, data such as grass / lawn cutting height in the target work area is set in step S501, and each rotation angle of the cut boundary detection mechanism 10 is set in step S502. Reciprocating members 12a, 12b for suspending left and right sled-shaped plates 13a, 13b which move up and down according to the height of grass / lawn cutting by signals from the sensors 14a, 14b.
To detect the angle of.

Next, the routine proceeds to step S503, where it is checked whether or not a fixed time has elapsed. If the fixed time has not elapsed, then the processing advances to step S502 described above to accumulate angle data. After that, when a predetermined time has elapsed and a predetermined number of angle data are accumulated, the process proceeds from step S503 to step S504 to average the accumulated left and right angle data, and the data set in step S501 is referred to. Left and right grass
Convert to turf height.

Then, the above steps S504 to S5
Go to 05, check whether or not there is a step greater than a predetermined value on the left and right grass / turf height converted in step S504, and if there is no step more than the predetermined value, in step S506 it is determined that there is no boundary line as described above. Returning to step S502, if there is a step difference equal to or larger than the predetermined value, the process proceeds to step S507 to capture the current position as a boundary line between the already-cut portion and the uncut portion, and exits the routine.

Data communication between the fixed station 30 and the mobile station in D-GPS is performed by packet data by the D-GPS wireless communication routine shown in FIG. In this data communication, the mobile station GPS receiver 15 is initialized in step S601, and the fixed station GPS receiver 33 is initialized by data transmission through the wireless communication devices 16 and 36 in step S602. Then, the differential information from the fixed station 30 is obtained by wireless data communication.

Next, in step S604, the D-GP
In the S position detection unit 53, the differential information from the fixed station 30 is applied to the positioning data obtained from the mobile station GPS receiver 15, and the differential operation is performed to measure the own vehicle position. Then, when the positioning information is sent to the traveling control unit 56, the process returns to step S603, and the next data processing is repeated. In this case, the differential calculation with the fixed station 30 may be performed by a function unique to the mobile station receiver 15.

[0065]

As described above, according to the present invention, when the moving distance to the target point is equal to or less than the set value, the autonomous traveling is controlled by the positioning data based on the traveling history from the reference position to reach the target point. When the travel distance exceeds the set value, the positioning data based on the travel history from the reference position is corrected by the satellite-based positioning data to control autonomous traveling, so the correction of the positioning data is adaptively switched according to the travel distance. It is possible to obtain excellent effects such as improvement of control stability.

[Brief description of drawings]

FIG. 1 is a block diagram of a control device.

FIG. 2 is a lawn mower equipped with a D-GPS mobile station and D
-Explanatory view showing a fixed station for GPS

FIG. 3 is an explanatory diagram showing a configuration of a cut boundary detecting mechanism.

FIG. 4 is an explanatory diagram showing an operation of a cut boundary detecting mechanism.

FIG. 5 is an explanatory diagram showing a configuration of a steering control system.

FIG. 6 is an explanatory diagram showing a travel route and a work area.

FIG. 7 is a flowchart of a main control routine.

FIG. 8 is a flowchart of a main control routine (continued)

FIG. 9 is a flowchart of a movement traveling control routine to a work area.

FIG. 10 is a flowchart of a D-GPS / dead reckoning mutual correction value calculation routine.

FIG. 11 is a flowchart of a current position calculation routine.

FIG. 12 is a flowchart of a cut boundary detection routine.

FIG. 13 is a flowchart of a D-GPS wireless communication routine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Lawn mowing work vehicle (autonomous vehicle) 30 ... Fixed station (first satellite-based positioning means) 50 ... Control device (second satellite-based positioning means, dead-reckoning positioning means, mutual correction value calculation means, autonomous running control Means) S ... Moving distance Df ... Threshold value (setting value)

Claims (1)

[Claims] 1. Receiving correction information from a first satellite-based positioning means that receives positioning information from a satellite at a known point and transmits correction information based on the positioning result, and receives the correction information and the above-mentioned satellite. Second satellite-based positioning means for positioning the position of the vehicle based on the positioning information, dead reckoning positioning means for calculating a travel history from a reference position, and positioning the position of the vehicle based on the travel history, Regardless of whether the vehicle is running or stopped, the difference between the two positioning data at the corresponding times of the second satellite-based positioning means and the dead-reckoning positioning means is calculated as a position correction value, Mutual correction value calculation means for moving average processing, and the moving distance from the current position of the vehicle to the target position based on the positioning data of the dead reckoning positioning means is compared with a set value,
When the moving distance is less than or equal to the set value, autonomous traveling is controlled based on the positioning data of the dead reckoning positioning means, and when the moving distance exceeds the set value, the mutual correction value calculating means performs averaging processing. An autonomous traveling vehicle characterized by comprising an autonomous traveling control means for controlling the autonomous traveling by correcting the positioning data by the dead reckoning positioning means with the latest position correction value to newly calculate the current position of the own vehicle. Travel control device.