JPH04611A - Steering controller for free-running car - Google Patents

Abstract

PURPOSE:To prevent the sight-loss of a light reflecting means extending over many hours by providing a light beam scanning means, a reference point sight- loss deciding means, a sight-loss frequent occurrence deciding means, and a means for operating a vertical direction scanning means of a light beam. CONSTITUTION:The controller is provided with a means for measuring an azimuth of light reflecting means 6a - 6d looked at from a free-running car by photodetecting a reflected light 2R of a light beam from the light reflecting means 6a - 6d installed in a reference point separated from the free-running car 1, and calculating a position of the free-running car, based on its result. Also, this controller is provided with reference point sight-loss deciding means 31, 32 for deciding whether the light reflecting means 6a - 6d installed in a scheduled reference point can be detected or not in accordance with whether an output of a photodetecting means or not, and a means 35 for deciding a fact that a sight-loss of the reference point occurs frequently, based on an output of the deciding means. In such a state, only in the case it is decided to be a reference point sight-loss, a beam scanning means 2 in the vertical direction is driven. In such a way, it does not occur to lose sight of the refer ence point frequently extending over many hours.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a steering control device for self-propelled vehicles, and particularly to a steering control device for self-propelled vehicles such as unmanned mobile conveyance devices in factories, agricultural and civil engineering machinery, etc. Regarding a control device.

(Prior Art) Conventionally, as a device for detecting the current position of a moving object such as the above-mentioned self-propelled vehicle, a device for scanning a light beam generated by the moving object in a circumferential direction centering on the moving object; A device has been proposed that is fixed at at least three points apart from the light source and is equipped with a light reflecting means that reflects light in the direction of incidence, and a light receiving means that receives the reflected light from the light reflecting means (Japanese Patent Application Laid-Open No. 59-6
Publication No. 7476).

The second device detects the aperture angle between the three light reflecting means as seen from the moving object based on the light receiving output of the light receiving means, and detects the aperture angle between the detected aperture angle and each preset light reflecting means. It is configured to calculate the position of the moving body based on the position information.

In the above system, the forward beam may not be able to be irradiated to the light reflecting means due to the tilt or shaking of the self-propelled vehicle, or the light receiving means may receive reflected light from a reflective object other than the light reflecting means. there were. If the scheduled reflected light from the light reflecting means cannot be received, the position of the self-propelled vehicle cannot be calculated, and as a result, the self-propelled vehicle may not be able to travel along the scheduled course.

In contrast, the applicant predicts the azimuth at which the same light reflecting means should be detected in the next scan based on the azimuth of the light reflecting means detected in the current and previous scans, and from this predicted azimuth. proposed a control device configured to determine that incident light is normal reflected light from a predetermined reflecting means (Japanese Patent Application No. 63-262192). The control device is configured to stop the self-propelled vehicle if the light reflecting means is repeatedly not detected in the predicted direction.

In addition, the applicant has determined that if no light reflecting means is detected in the predicted direction, as an emergency measure, at least the light reflecting means should have been detected in the vicinity of the predicted direction. A control device was also proposed that uses predicted azimuth data in place of the actual azimuth to detect the position of a self-propelled vehicle (Japanese Patent Application No. 12424/1999).

(Problems to be Solved by the Invention) With the above control device, if the light reflection means is temporarily lost, the self-propelled vehicle will not be stopped, and the predicted direction will not be changed to the actual light reflection means. Even if the predicted azimuth data is used to detect the position of the self-propelled vehicle, the error in detecting the position of the self-propelled vehicle is small, so there is no problem.

However, depending on the condition of the running surface, the light reflecting means may be lost for a long time. In this case, the light reflecting means is lost at each detection timing, resulting in a state where the light reflecting means is frequently lost. In such a state of frequent loss of sight, if the predicted azimuth angle is repeatedly used to calculate the position of the self-propelled vehicle, errors in the calculation results will accumulate, making it impossible to accurately guide the self-propelled vehicle. If the error in the calculation results becomes large, the self-propelled vehicle must be stopped, and if the self-propelled vehicle is stopped frequently, there is a problem in that work efficiency is significantly reduced.

As a measure to prevent frequent loss of sight caused by the condition of the running surface, a device that scans in the circumferential direction while swinging the light beam in the vertical direction (for example, Japanese Patent Application Laid-Open No. 60-242313 The device described in ) has been proposed.

By the way, in this device, unless the light beam swing speed in the vertical direction is increased and the light beam scanning density in the circumferential direction is increased, the problem of frequent loss of sight cannot be significantly improved.

However, in order to increase the scanning density of the light beam, it is necessary to use a motor that rotates at high speed (for example, 20,000 rpm or more) and a bearing with high wear resistance. It is necessary to use a high-grade rocking mechanism that is durable enough to withstand continuous use.

An object of the present invention is to solve the problems of the prior art as described above, to prevent the light reflecting means from being lost for a long time, and as a result, to avoid a decrease in work efficiency and an increase in position detection errors of self-propelled vehicles. An object of the present invention is to provide a steering control device for a self-propelled vehicle.

(Means and Effects for Solving the Problems) In order to solve the above-mentioned problems and achieve the objects, the present invention provides a beam that scans a light beam in the circumferential direction and in the vertical direction with the self-propelled vehicle as the center. Receiving the reflected light of the light beam from a scanning means and a light reflecting means installed at a reference point distant from the self-propelled vehicle and measuring the azimuth angle of the light reflecting means as seen from the self-propelled vehicle; means for calculating the position of the self-propelled vehicle based on the reference point; means for determining whether or not the light reflecting means installed at the scheduled reference point has been detected based on the presence or absence of an output from the light receiving means; It is characterized by comprising means for determining whether the reference point is frequently lost based on the output of the determining means, and configured to drive the vertical beam scanning means only when it is determined that the reference point has been lost. There is.

In the present invention having the above configuration, when the reference point is detected normally, the light beam is scanned in the circumferential direction while the vertical scanning angle is fixed, and it is detected that the reference point is frequently lost. In this case, the light beam is also scanned in the vertical direction. Therefore, the opportunity to use the light beam vertical scanning means is limited, and the durability of the swinging mechanism that constitutes the light beam vertical scanning means can be improved.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view showing the arrangement of a self-propelled vehicle equipped with the control device of the present invention and a light reflector disposed in the travel area of the self-propelled vehicle. In the figure, a self-propelled vehicle 1 is, for example, a self-propelled vehicle for agricultural work such as a lawn mower.

The self-propelled vehicle 1 is equipped with an optical scanner 2. The optical scanner 2 consists of a fixed part 2a and a rotating part 2b, and the rotating part 2b is connected to a motor 5 by a belt.
It is driven by the motor 5 and rotates, for example, counterclockwise.

The light beam 2E generated by the light emitter of the optical scanner 2 is scanned in the direction of the arrow 29 as the rotating part 2b rotates.

Further, the rotating section 2b includes a swing mechanism that causes the generated light beam to scan in the vertical direction.

A plurality of reference points are set around the work area, and reflectors 6a to 6d made of well-known light reflecting means such as a corner cube prism having a reflective surface that reflects incident light in the direction of incidence are installed at the reference points. will be installed. A light beam 2E scanned from the optical scanner 2 in the direction of the arrow 29 is sequentially reflected by these reflectors 6a to 6d, and the reflected light 2R is sequentially received by the light receiver of the optical scanner 2. The light emitter consists of a light emitting diode, and the light receiver consists of a photodiode.

The rotating part 2b is provided with a slit plate 7a, and the rotating part 2b is provided with a slit plate 7a.
rotates with. By providing an angle sensor that outputs a pulse signal every time the slit of the slit plate 7a is detected, the rotation angle of the rotating portion 2b can be detected based on the counted value of the pulse.

Note that if the light emitted from the light emitter is configured so that it is once reflected by a mirror and then projected to the outside from the optical scanner 2, and the mirror is swung by a motor to scan the light beam up and down, good. A specific example of the vertical scanning means for the light beam is described in Japanese Patent Application No. 2-33444.
The present invention is not limited to this scanning means, and other well-known scanning means can be used.

Further, for the sake of explanation, the optical scanner 2 is shown in an exposed state, but it goes without saying that it is provided with a dust-proof and drip-proof cover.

With the above configuration, the light beam 2E generated by the light emitter of the optical scanner 2 is scanned in the scanning direction 29, and is detected by the light receiver of the optical scanner 2 in the order of reflected light from the reflectors 6a to 6d. Steering control is performed by detecting the self-position of the self-propelled vehicle 1 with respect to the reflectors 6a to 6d based on the detection signal.

Next, a method for identifying the reflector placed at the reference point and other reflective objects will be described. FIG. 8 is an explanatory diagram of the reference point identification process. In the figure, the reflectors 6a to 6d are arranged at reference points A to D around the working area 22, respectively. An arrow 29 indicates the scanning direction of the light beam emitted from the self-propelled vehicle 1.

In the arrangement shown in the figure, the azimuth angle of each reference point is calculated based on the detection signal of the light receiver 3, and the same reference point is detected in the next scan based on the azimuth angle detected up to this point. The correct azimuth is predicted. The predicted azimuth angle (predicted azimuth angle) of each reference point is the angle θpa.
~θpd.

Light beam scanning direction 29 from each predicted azimuth θpa to θpd
The reference point identification direction pa is set in the direction in which the scanning has progressed by the angle θh.
-pd is provided. Of these reference point identification directions pa-pd, among the lights detected between two adjacent reference point identification directions, the incident light from the direction closest to the predicted azimuth angle is It is determined that the light is from a reflector.

For example, the reference point identification direction pd and the reference point identification direction pa
Assume that light from the noise sources Nl and N2 and reflected light from the reflector 6a installed at the reference point A are detected during this period. In this case, by extracting the light from the direction closest to the predicted azimuth θpa from among these lights, the reflected light from the reference point A can be distinguished from the light from the other light sources Nl and N2 and detected. .

Furthermore, the following process can be added to improve the accuracy of identifying reference points. In other words, if a predetermined range (an angle equal to or smaller than the angle θh) is set before and after the predicted azimuth, and even light from the direction closest to the predicted azimuth θpa to θpd deviates from the range. It is determined that the planned reference point has been lost.

When it is determined that the scheduled reference point has been lost because no light is detected between the two reference point identification azimuths or within the scheduled range set to improve identification accuracy, the processing cycle is started using the predicted azimuth angle. The position of the self-propelled vehicle 1 is calculated, and the predicted azimuth is further stored as the next predicted azimuth.

Next, a calculation procedure for detecting the position and traveling direction of the self-propelled vehicle 1 will be explained. 10 and 11 show the positions of the self-propelled vehicle 1 and the reflector 6 in a coordinate system for indicating the working range of the self-propelled vehicle 1. FIG.

In FIGS. 10 and 11, reference points A, B, and C, where reflectors 6a to 6C are arranged, and the position of self-propelled vehicle 1 are expressed by a straight line connecting reference points B and C with reference point B as the origin. It is expressed in an x-y coordinate system with .

As can be understood from the figure, the position T of the self-propelled vehicle 1 is on the circumcircle of the triangle ATB and at the same time
Exists on the circumcircle of Therefore, the position of the self-propelled vehicle 1 is the circumcircle Q of each of triangle ATB and triangle BTC.
It is obtained by calculating the two intersection points of and P.

As shown in the figure, the position of the self-propelled vehicle 1 can be determined by setting the reference point B, which is the intersection of one of the circumscribed circles Q and P, as the origin, and calculating the other intersection T of the circumscribed circles Q and P according to the following procedure. .

The calculation formula for determining the position of the self-propelled vehicle 1 is disclosed in Japanese Patent Application Laid-open No. 1-287.
415 and Japanese Unexamined Patent Publication No. 1-316808, the description thereof will be omitted.

The traveling direction of the self-propelled vehicle 1 is calculated using the following formula. 1st
In Figure 1, the angle between the traveling direction of the self-propelled vehicle 1 and the
, the azimuthal angles are θa and θb.

When θC, θf- 360°-tan' ty/ (x c-x))
-θC...(1)

The position and traveling direction of the self-propelled vehicle 1 are calculated by the position and traveling direction calculating section 13, which will be described later, using the above-mentioned calculation formula and the above-mentioned calculation formula (1).

Next, steering control of the self-propelled vehicle 1 based on the position information of the self-propelled vehicle 1 calculated by the above procedure will be explained. FIG. 9 is a diagram showing the positional relationship between the travel course of the self-propelled vehicle 1 and the reference points. The location of the vehicle 1 and the work area 22 by it are shown.

Point R (Xret, Yret) indicates the return position of the self-propelled vehicle 1, and has coordinates (Xs t, Ys t), (Xst.

The area connected by the points indicated by Ye), (Xe, Yst), and (Xe, Ye) is the work area 22.

In this example, the position T of the self-propelled vehicle 1 is indicated by (Xp, Yp).

The self-propelled vehicle 1 starts traveling from a work start position S, sequentially travels through a straight stroke and a turning stroke for transitioning from one straight stroke to the next straight stroke to perform scheduled work such as mowing the lawn.

The self-propelled vehicle 1 starts turning when the y-coordinate reaches Ye in the forward direction (upward on the drawing) and when the y-coordinate reaches Yst in the return direction (downward on the drawing). .

The y-coordinate of the end point of the turn is also the same as the y-coordinate of the start point of the turn, but since the coordinates of the self-propelled vehicle 1 cannot be detected accurately during the turn, it is difficult to determine whether the self-propelled vehicle 1 has reached the end point of the turn. , self-propelled car 1
Judgment is made based on the azimuth data of the reference point as seen from.

Specific examples of steering control during the turning process and judgment of turning completion are as follows:
Japanese Patent Application Publication No. 1-318808 and Japanese Patent Application No. 19293-1993
listed in the number.

In addition, in FIG. 9, in order to simplify the explanation, an example is shown in which the work area 22 is parallel to the X axis or the y axis.
Reference points A around the work area 22.

As long as B, C, and D are arranged, the shape of the work area 22 and the orientation of the four sides of the work area 22 are arbitrary.

Next, the functional configuration of the control device of this embodiment will be explained according to the block diagram shown in FIG. In the figure, the part surrounded by chain lines can be constructed by a microcomputer.

FIG. 1 shows a steering control function of a self-propelled vehicle, a reference point identification function, and a function for detecting frequent loss of reference points from identification results obtained by the reference point identification function and for dealing with this.

In FIG. 1, a light beam 2 emitted from a light emitter 3a
E is scanned in the rotating direction of the rotating section 2b, and the reflector 6
(6a-6d). The reflectors 6a-6
The reflected light 2R of d is received by the light receiver 3b.

The counter 9 counts pulses output from the angle sensor 7b as the slit plate 7a of the rotating section 2b rotates. The count value of the pulse is transferred to the azimuth detecting section 11 every time the light receiver 3b detects light. The azimuth detecting section 11 detects the reflector 6a based on the number of supplied pulses.
An azimuth angle of ~6d is calculated.

The azimuth detected by the azimuth detection unit 11 is stored in the azimuth storage unit 1.
The data stored in the azimuth storage unit 12 is transferred to the azimuth identification unit 24 in response to the identification timing signal supplied from the identification timing generation unit 23.

The identification timing signal is transmitted to the reference point identification azimuth pa-pd at the point in time when the scanning advances to an azimuth that passes through the azimuth indicated by the predicted azimuth calculated by the azimuth angle prediction calculation unit 27 by a predetermined angle θh. It is output when the beam scan progresses. For this purpose, the identification timing generator 23
Then, when the number of output pulses from the angle sensor 7b corresponding to the angle obtained by adding the angle θh to the predicted azimuth angle calculated by the azimuth angle prediction calculating section 27 is taken in, an identification timing signal is output.

The azimuth identification unit 24 selects the light detected in the direction closest to the predicted azimuth calculated by the azimuth prediction calculation unit 27 from among the supplied azimuths from a reflector placed at a predetermined reference point. It is determined that the light is reflected light.

The azimuth angle data of the reflector determined by this judgment is
It is used when the azimuth prediction calculation unit 27 predicts the azimuth of the reflector to be detected in the next scan.

That is, the predicted azimuth is determined by a function of the azimuth determined by the azimuth angle identification unit 24 that is expected to be obtained experimentally. The predicted azimuth is not limited to the method of finding it based on a predetermined function, but may be found by adding the difference between the current and previous azimuths obtained by the azimuth identification unit 24 to the current azimuth.

The azimuth detected by the azimuth angle identification section 24 is determined by the opening angle calculation section 1.
0, and the opening angle between the reflectors 68 to 6d as seen from the self-propelled vehicle 1 is calculated.

The position/progressing direction calculating section 13 calculates the current position coordinates of the self-propelled vehicle 1 based on the aperture angle, and also calculates the traveling direction of the self-propelled vehicle 1 based on the azimuth angle. This calculation result is input to the position/direction comparison section 25. The position/direction comparison unit 25 compares the data representing the travel course set in the travel course setting unit 16 with the coordinates and travel direction of the self-propelled vehicle 1 obtained by the position/direction calculation unit 13. be done.

The comparison result is input to the steering section 14, and the steering motor 28 connected to the front wheels 17 of the self-propelled vehicle is driven based on the comparison result. The steering angle of the front wheels 17 by the steering motor 28 is detected by a steering angle sensor 15 provided on the front wheel of the self-propelled vehicle 1 and fed back to the steering section 14 . Drive control section 1
8 starts and stops the engine 19, and the engine 19
The operation of the clutch 20 that transmits the power to the rear wheels 21 is controlled.

Furthermore, the following functions are added to improve the accuracy of identifying reference points. That is, a value indicating the angular range set in the range setting section 26 is supplied to the azimuth angle identification section 24, and it is determined whether the light detected in the direction closest to the predicted azimuth is detected within the planned angular range. A function is added to identify whether or not the

As a result of the identification by the identification function, if the light detected in the direction closest to the predicted azimuth is within the planned range, the aperture angle is calculated using the azimuth; if it is outside the planned range, the aperture angle is calculated. , the aperture angle is calculated using the predicted azimuth calculated by the azimuth angle prediction calculation unit 27.

The light from the angular range set in the range setting unit 26 is determined to be reflected light from the scheduled reference point, and the aperture angle is calculated using the azimuth of the illumination. Whether the opening angle is calculated using the azimuth determined without determining whether it is within the range set in the section 26 is necessary depending on the type and type of work performed by the self-propelled vehicle 1. It may be arbitrarily selected depending on the degree of accuracy.

Note that the configuration of the lost-of-sight determining means shown in this embodiment is not limited to the configuration, and the detection range of the predicted azimuth angle may be set narrowly, and loss of sight of the reference point may be determined based on whether or not a received light signal is detected within the range. Simple method for determining loss of sight (patent application 1986-26)
2192) can also be applied to the present invention.

In FIG. 1 (part 2), the identification result as to whether the reference point has been detected or lost is supplied from the azimuth angle identification section 24 to the continuous displacement counting section 30. The continuous left-behind counting section 30 counts the number of times that each reference point is not detected consecutively for all the reference points. Therefore, the continuous leaving counting section 30 is provided with counters corresponding to all the reference points set in the work area. For this purpose, in this embodiment, four counters M1 to M4 are provided corresponding to the reference points A to D, respectively. The count values of the counters M1 to M4 are incremented by the lost sight signal supplied from the azimuth angle identification section 24, and the count values are cleared by a signal indicating that the scheduled reference point has been detected.

Based on the counts of counters M1 to M4 provided in the continuous leaving counting section 30, the first determining unit 31 determines the scheduled number of times L2. L3. It is determined whether the reference point has not been detected continuously for L4 or more.

Similarly, the second consecutive abandonment count second determination unit 32 determines the second scheduled count L5. L6. Reference points that have not been detected continuously for L7 or more are determined. The relationship between the scheduled number of times L2 to L7 is (L2<L5.L3<L6゜L4<L7), and (
(L2>L3>L4) and (L5>L6>L7). In this example, L2 is “6” and L3 is “3”.
, L4 was set to "1".

The first counting unit 33 for the number of missed items calculates each scheduled number of times L2 to L4 based on the output of the first determining unit 31 for the number of continuous items left behind.
The number of reference points that have not been detected consecutively is counted, and the second number of missed reference points counting section 34 calculates the second number of consecutive missed reference points.
Based on the output of the determination unit 32, each scheduled number of times L5~
The number of reference points that have not been detected continuously for L7 or more is counted.

In this embodiment, three counters C2 to C4 are provided in the first counting unit 33 for the number of missed lines. The number of reference points is now counted. Counter C2 counts the number of reference points that could not be detected consecutively for more than the scheduled number of times L2 based on the values of counters M1 to M4, and counters C3 and C4 could not be detected consecutively for more than the scheduled number of times L3 and L4, respectively. The number of reference points is counted based on the values of counters M1 to M4. The values of counters C2-C4 are cleared at the beginning of this process.

In the second counting unit 34 for the number of missing lines, the counter C20°C30
, C40, the number of reference points that have been missed consecutively more than the scheduled number of times L5 to L6 is detected. counter C2
0 counts the number of reference points that could not be continuously detected for the scheduled number of times L5 or more, and counters C30 and C40 count the number of reference points that could not be continuously detected for the scheduled number of times L6 or L7 or more, respectively. The values of the counters C20, C30 and C40 are also cleared at the beginning of this process, similar to the values of C2 to C4.

The frequency determining unit 35 determines that the reference point has been frequently lost when the values of the counters C2, C3, and C4 are "2," 3, and 4, respectively.

In other words, if you lose sight of all four reference points consecutively, if you lose sight of three reference points three or more times in a row, or if you lose sight of two reference points six or more times in a row, It is determined that there were many points left unattended.

When a signal indicating that the reference point has been frequently lost is supplied from the reference point misplacement frequent determination section 35 to the vertical scanning motor control section 36, the motor control section 36 supplies a drive signal to the vertical scanning motor 8. On the other hand, if the reference point misplacement frequent determination unit 35 determines that the reference point is not frequently lost, the motor control unit 36 outputs a drive stop signal to the vertical scanning motor 8.

Further, the switching section 37 is normally open, and is connected when the reference point misplacement frequent occurrence determination section 35 supplies the lost-of-place frequent signal, and the lost-of-place limit determination section Output to 38.

The loss of sight limit judgment unit 38 determines whether the loss of sight tolerance limit has been exceeded under conditions that are looser than the judgment criteria of the frequent occurrence judgment unit 35, that is, the scheduled number of times L5 to L7 is set to be large in order to allow a higher number of continuous abandonment. I tried to judge.

If the loss of sight exceeds the permissible limit, the loss of sight limit determining section 38 outputs a signal to the drive control section 18 of the self-propelled vehicle 1 to stop the self-propelled vehicle 1, and also outputs a signal to the drive control section 18 of the self-propelled vehicle 1, and also includes an alarm generating means and a display means (both shown in the figure). (not shown) also outputs a signal exceeding the allowable limit.

The control procedure will be explained according to the flowchart in FIG.

First, in step S1, the self-propelled vehicle 1 is moved from point R to the work start position by radio control.

In step S2, Xs is set as the X coordinate Xn of the driving course.
Set t and determine the driving course.

In step S3, the self-propelled vehicle 10 starts running.

In step S4, it is determined whether the light receiver 3b has received light from the reference point or another light source. If light is detected, the process proceeds to step S5, where a light reception process to be described later is performed, and if no light is detected, the process proceeds to step S6.

In step S6, it is determined whether or not it is time to perform a reference point identification process to determine which of the received incident lights is from a scheduled reference point. This determination is made based on whether the scanning has progressed to any of the reference point identification directions pa to pd, which are advanced by a predetermined angle θh from the predicted azimuths θpa to θpd.

Steps S4 to S until the judgment in step S6 becomes affirmative
Step 6 is repeated, and if the determination is affirmative, the process proceeds to step S7, where a reference point identification process, which will be described later, is executed. Once the azimuth of the scheduled reference point is determined by the reference point identification process, the process proceeds to step S8.

In step S8, arithmetic processing for determining a frequent loss of sight, which will be described later, is performed.

In step S9, it is determined based on the arithmetic processing as to whether or not the reference point is being lost more frequently than a predetermined value.

If the determination in step S9 is affirmative, the process advances to step S10. In step SIO, the frequent loss of sight was observed in the self-propelled vehicle 1.
The loss of sight limit is determined to determine whether the condition is so serious that it is necessary to stop the vehicle from traveling (the loss of sight limit), or whether there is still room to scan the light beam vertically to search for the reference point. Perform the calculation for. An example of the loss limit determination process will be described later.

In step S11, it is determined whether the loss of sight of the reference point has reached the limit based on the result of the loss limit determination process.

If the judgment in step Sll is affirmative, a warning for leaving the reference point is issued or displayed (step 512), and the traveling of the self-propelled vehicle 1 is stopped (step 513).

On the other hand, if the determination in step S11 is negative, step 5
In step 14, the motor for vertically scanning the light beam is driven.

If it is determined in step S9 that the reference point is not frequently lost, the process proceeds to step S15, where it is determined whether the vertical scanning motor is being driven. If the vertical scanning motor is being driven, the process advances to step S16 and a stop signal is supplied to the motor.

If it is determined that the vertical scanning motor is not being driven, step S16 is skipped and the process proceeds to step S17.

In step S17, the position T (Xp) of the self-propelled vehicle 1.

Yp) and the traveling direction θf are calculated.

In step 31g, the amount of deviation from the running course (ΔX-
Xp-Xn, Δθf) is calculated, and in step S19, steering angle control is performed in the steering section 14 according to the calculated deviation amount.

In step S20, it is determined whether the self-propelled vehicle 1 is traveling in a direction away from the origin (going direction) in the y-axis direction or is traveling in a direction approaching the origin (returning direction).

If it is the forward direction, it is determined in step S21 whether the -stroke has ended (Yp>Ye); if it is the return direction, it is determined in step S22 whether the -stroke has ended (Yp>Ye).
<Ys t) is determined. Step S21
Alternatively, if it is determined in S22 that the -stroke has not been completed, the process returns to step S4.

If it is determined in step S21 or S22 that the -stroke has ended, then in step 823 it is determined whether all the strokes have ended (Xn>Xe-L).

If the entire stroke has not been completed, the process moves from step S23 to step S24, and a U-turn control of the self-propelled vehicle 1 is performed. The U-turn control is different from the straight-line steering control performed by the processing of steps 817 to S19 in which the position information of the self-propelled vehicle 1 calculated by the position/direction calculation unit 13 is fed back to the steering unit 14. It is done by method.

That is, during the turning stroke, the self-propelled vehicle 1 travels with the steering angle fixed at a preset angle.

Then, each reference point A, B, C for the self-propelled vehicle 1
When at least one of the azimuth angles D matches a predetermined angle or falls within a predetermined angle range, the turning is stopped and the steering control returns to straight-line travel.

In step S25, Xn is set to Xn+L, and the driving course for the next stroke is set. Once the travel course is set, the process returns to step S4 and the above process is repeated.

When the entire stroke is completed, the return position R (Xret.

Yret) (step 526), and the traveling is stopped (step 527).

Next, the light reception process and reference point identification process in steps S5 and S7 will be explained.

A flowchart of the light reception process is shown in FIG. In the figure, in step S50, the light reception flag is set to "1" in order to memorize that light has been detected.

In step S51, the azimuth of the detected light source is stored in the azimuth storage section 12.

A flowchart of the reference point identification process is shown in FIG. This flowchart shows an example of a procedure for further narrowing down the detected azimuth angle closest to the predicted azimuth angle using a scheduled angle set in the range setting section 26 to identify a reference point.

In the figure, in step s70, a value n of a pole counter (hereinafter simply referred to as a pole counter) for distinguishing a reference point to be identified is incremented. The pole counter is associated with each reference point. In other words, the pole counter "1" is at the reference point A, and the pole counter "2" is at the reference point A.
corresponds to the reference point B, the pole counter "31" corresponds to the reference point C, and the pole counter "4" corresponds to the reference point.

If the initial value of the poll counter is “0”, step S
As a result of the process 70, the poll counter becomes "1", and the reference point corresponding to this becomes "A". In this embodiment, the initial value is set to "0".

In step S71, the light reception flag is determined. If the light reception flag is "1", the process proceeds to step S72, and if the light reception flag is "0°, the process jumps to step S79.

In step S72, the predicted azimuth θpn (since the pole counter is “1”, the predicted azimuth θp
Assume that the one closest to a) is the azimuth angle of the scheduled reference point, and store that value as the angle θS.

In step S73, the presence or absence of noise is determined by determining whether the number of received lights is 2 degrees or more, that is, whether a plurality of azimuths are stored in the azimuth storage section 12.

If the determination in step 57.3 is affirmative, it is assumed that one or more noises have been detected, and the process moves to step S74, and the fact that noise has been detected is stored as noise processing. This stored data can later provide clues about the state of the work environment, making it easier to take measures such as eliminating noise sources.

If the judgment in step S73 is negative, the process proceeds to step S75, where the temporarily determined azimuth θS and the predicted azimuth θp are
It is determined whether the difference between the angle θh and the azimuth angle θpa is smaller than the angle θh. If the error is larger than the angle θh, it is determined that the temporarily determined azimuth θS is not the azimuth of the planned reference point but the azimuth of the noise source, and the process proceeds to step 578, where the same noise as in step S74 is detected. Perform processing.

After the noise processing, the process proceeds to step S79, where the predicted azimuth θpn (predicted azimuth θpa
) is set as the azimuth angle θn (θa) of the scheduled reference point.

In step S80, a counter Mn that counts the number of consecutive times the reference point is lost is incremented. In other words,
Here, the pole counter n is incremented by the count value of the counter M1, which counts the number of times the reference point A is continuously left behind.

On the other hand, if the difference (θS - θpn) is smaller than the angle θh, the assumed azimuth θS is determined to indicate the azimuth of the scheduled reference point, and the process proceeds to step S76.

In step S76, the azimuth θ determined in the previous process is
Based on n and the azimuth θS determined in the current process, the predicted azimuth at which the same reference point should be detected in the next process is calculated using the calculation formula (θS+(θSθn)l).

In step S77, the azimuth angle θn is updated by the angle θS.

In step S81, the count value of the counter Mn, that is, Ml is cleared.

In step S82, the next reference point identification direction pn+1(
That is, the predicted azimuth θpn+1 calculated when the reference point B was detected during the previous scan as the reference point identification azimuth pb)
The angle obtained by adding the planned angle θh to is set.

In step S83, the light reception flag is cleared.

In step S84, the data stored in the azimuth storage section 12 is erased.

In step S85, it is determined whether the poll counter is "4" or not. The error value "4" is the number of installed reference points, and the error value is set according to the number of installed reference points.

If the number of installed reference points matches the pole counter, the pole counter is set to "0#" in step S85 and the process returns to the main routine (processing in FIG. 3).

When the pole counter is "1", in the next process, the pole counter is incremented to "2" in step S70, and the reference point B identification process is performed.

Thereafter, the identification process of the reference point C and the reference point is also performed in the same manner.

Next, the determination of frequent loss of sight will be explained. FIG. 6 is a flowchart of the process of determining how often people lose sight of the object.

In step S91, the counters C2 to C4 count the number of reference points that have been missed consecutively for a predetermined number of times or more.
and clear the counter n. Note that this counter n is another counter corresponding to the above-mentioned pole counter n (FIG. 4), and the contents of the pole counter n itself are not changed.

In step S92, a counter n is incremented.

In step S93, the count value of the counter Mn (that is, Ml) of the continuous left-behind counting section 30 is changed to the scheduled number of times L4 (that is, "
If the judgment is affirmative, the process moves to step S94 and the counter C4 is incremented.

In step S95, it is determined whether the count value of counter Mn (that is, Ml) is equal to or greater than the scheduled number of times L3 (that is, "3" or more), and if the judgment is affirmative, the process moves to step S96 and counter C3 is incremented.

In step S97, it is determined whether the count value of the counter Mn (that is, Ml) is equal to or greater than the scheduled number of times L2 (that is, "6" or more), and if the judgment is affirmative, the process moves to step 39g and the counter C2 is incremented.

In step S99, by determining whether the pole counter n is "4", it is determined whether all the counts of the counters M1 to M4 have been checked.

Based on the judgment in step S99, counters M1 to M4
When it is determined that all counts up to the point have been checked,
Proceed to step 5100.

In step 5100, the count value of counter C2 is "2".
In other words, it is determined whether there are two or more reference points that could not be detected six or more times in a row. If the determination is negative, the process proceeds to step 5101, where it is determined whether the count value of the counter C3 is "3" or more, that is, whether there are three or more reference points that could not be detected three or more times in a row.

Further, if the determination is negative, proceed to step 5102;
It is determined whether the count value of the counter C4 is "4" or more, that is, whether there are four or more reference points that could not be detected one or more times in a row. That is, in step 5102, it is determined whether all reference points could not be detected continuously.

If all steps 8100 to 5102 are negative,
It is determined that the loss of sight does not occur frequently, and the frequent loss of sight flag is cleared (step 5103).

On the other hand, if the determination result in any of steps 8100 to 5102 is affirmative, it is determined that reference point firings occur frequently, and a flag for frequently losing sight is set (step 5104).
.

Next, the loss of sight limit judgment will be explained. FIG. 7 is a flowchart of the loss of sight limit determination process.

In the loss limit determination, the number of times each reference point A to D is continuously left behind, counted by a counter Mn (n is 1 to 4), is the scheduled number of times L5. L6. Steps S33 to S537) to determine whether or not L7 has been reached, the counter C
20, C30, and C40, the number of reference points at which the number of consecutive placements has reached the scheduled number of times L5 to L7 is counted (steps S34 to S538). Finally, the counter C
It is determined whether each of 20 degrees C30 and C40 has reached a scheduled value (steps 540-842).

If it is determined that the loss of sight limit has been reached, the loss of sight limit flag is set to "1" (step 543); if the loss of sight limit has not yet been reached, the loss of sight limit flag is set to "0'".
is set (step 544).

In this way, the loss of sight limit determination process is performed using the same processing method as the loss of sight frequent determination process. However, as described above, the scheduled number of times L5 to L7, which is the criterion for incrementing the counters C20, C30, and C40, is based on the relationship (L7<L6<L5) and the number of times L5 to L7 is the criterion for incrementing the counters C20, C30, and C40.
L7 is the number of times L2 to L in the case of the frequent loss of sight determination process.
For 4 (L2<L5.L3<L6.L4<L7)
Numerical values are set such that the relationship is as follows.

That is, in the loss of sight limit determination, the loss of sight limit is determined under conditions that are looser than those used to determine the frequent loss of sight in the frequent loss of sight determination process.

As described above, in this embodiment, strict criteria are used to detect that the reference point is frequently lost, and only when it is detected that the reference point is frequently lost, in addition to scanning the light beam in the circumferential direction, The loss of sight is resolved by scanning the light beam in the vertical direction as well, and the criteria for determining the occurrence of frequent loss of sight are set in cases where the loss of sight is not resolved even though the light beam is scanned in the vertical direction as well. We decided to use a higher number of consecutive abandonments as the criterion for determining the number of consecutive abandonments. In addition, if it is determined that the number of reference point ignitions has reached its limit despite the light beam being oscillated and scanned in the vertical direction, the self-propelled vehicle is stopped. .

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects can be obtained.

(1) When a large number of reference point fires are detected, the forward beam is also scanned in the vertical direction, so the self-propelled vehicle will not be tilted for a long time when working on a highly uneven running surface. Even when driving, the reference point is no longer frequently lost, and steering control can be performed based on accurate positional information of the reference point.

(2) Since the light beam is scanned in the vertical direction only when there are multiple occurrences of reference point firing, the durability of the mechanism for vertical scanning is improved, and the vertical scanning Since the electric power required to drive the electric motor can be saved, it is not necessary to reduce the size and weight of batteries installed in self-propelled vehicles.

(3) On flat land, the vertical scanning angle of the light beam is fixed, and the movement on flat land is faster than when the light beam is always scanned with a wavy trajectory that is a combination of vertical and circumferential scanning. Then, the frequency of leaving the reference point will decrease.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the functions of an embodiment of the present invention, FIG. 2 is a perspective view showing the arrangement of a self-propelled vehicle and a reflector, and FIG.
Figure 4 is a flowchart of steering control, Figure 4 is a flowchart of reference point identification processing, Figure 5 is a flowchart of light reception processing, Figure 6 is a flowchart of determination of frequent loss of sight, Figure 7 is a flowchart of determination of limit of loss of sight, and Figure 8 is a flowchart of determination of loss of sight. Figure 9 is an explanatory diagram of reference point identification processing, Figure 9 is a diagram showing the traveling course of a self-propelled vehicle and the arrangement of reflectors, Figure 10 is an explanatory diagram of the principle of position detection of a self-propelled vehicle, and Figure 11 is a diagram illustrating the principle of position detection of a self-propelled vehicle. FIG. 3 is a diagram explaining the principle of detecting the traveling direction of a vehicle. ... Slit plate, 7b... Angle sensor, 8... Vertical direction scanning motor, 11... Azimuth angle detection unit, 12...
- Azimuth storage unit, 13...Position/progressing direction calculation unit, 2
3... Identification timing generation section, 24... Azimuth angle identification section, 26... Range setting section, 27... Azimuth angle prediction calculation section, 30... Continuous prefecture center counting section, 31...・Continuous prefecture centering number first discrimination section, 32...Continuous prefecture centering number second discrimination section, 33...Lost track number first counting section, 34...Lost track number second counting section, 35...・Multiple occurrence judgment department, 36...
Vertical direction scanning motor control section, 37... switching section, 3B
... Loss of sight limit judgment department agent Patent attorney Michito Hiraki 1 other person 1... Self-propelled vehicle, 2... Optical scanner, 3a... Emitter, 3b... Light receiver, 6, 6a ~ 6d...Reflector, Figure 7a (Part 2) Figure 2 Figure 8 Figure 5 Figure 11 Date

Claims (9)

[Claims] (1) A light beam is scanned in the circumferential direction around the self-propelled vehicle, and the reflected light of the light beam is received from a light reflecting means placed at a reference point distant from the self-propelled vehicle. A steering control device for a self-propelled vehicle that measures an azimuth angle of the light reflecting means as seen from the vehicle and runs the vehicle based on the result, comprising: a light beam scanning device that scans the light beam in the vertical direction as well; means, reference point loss determination means for determining whether or not the light reflecting means has been detected based on the presence or absence of reflected light from a planned direction to be received by the self-propelled vehicle; A method for determining whether the reference point is frequently lost, and only when it is determined that the reference point is frequently lost.
A steering control device for a self-propelled vehicle, comprising means for operating said light beam vertical scanning means. (2) Loss of sight limit determination that determines that the number of times of losing sight of a reference point has reached a predetermined limit in accordance with a criterion that is looser than the standard for determining that the number of times of losing sight of a reference point is occurring frequently by the loss of sight frequent determining means. Claim 1, further comprising means for stopping the traveling of the self-propelled vehicle when it is determined by the loss of sight limit determining means that the loss of sight of the reference point has reached a predetermined limit.
The steering control device for the self-propelled vehicle described above. (3) The loss of sight frequent determining means includes a counting means for detecting the number of light reflecting means that cannot be detected consecutively for a predetermined number of times; 3. The steering control device for a self-propelled vehicle according to claim 1, further comprising means for outputting a frequent loss-of-track signal when it is determined that detection has not been performed consecutively for a predetermined number of times or more. (4) The loss limit determining means includes a counting means for detecting the number of light reflecting means that cannot be detected consecutively for a predetermined number of times; 4. Steering of a self-propelled vehicle according to claim 3, further comprising means for outputting a loss of sight limit signal when it is determined that detection has not been possible consecutively for more than a second predetermined number of times, which is greater than the first predetermined number of times. Control device. (5) The reference point loss determining means includes: means for detecting the azimuth of each light reflecting means as seen from the self-propelled vehicle based on the reflected light; and based on the azimuth detected by the azimuth detecting means. , azimuth prediction means for calculating the azimuth at which each light reflection means should be detected in the next scan; It is characterized by comprising a reference point identification means for identifying whether the light reflected by the light reflecting means is detected by the identification means, and a means for outputting a lost signal when the light reflected from the intended light reflecting means is not detected by the identification means. A steering control device for a self-propelled vehicle according to any one of claims 1 to 4. (6) The reference point identification means determines the immediately preceding reference point identification direction and Among the incident lights detected during the current reference point identification azimuth, it is assumed that the incident light from the angle closest to the predicted azimuth is the reflected light from the light reflecting means arranged at the planned reference point, and this 6. The steering control device for a self-propelled vehicle according to claim 5, further comprising means for treating the object as an object to be identified by said identifying means. (7) Only when the incident light from the angle closest to the predicted azimuth angle is light from an angular range established with the predicted azimuth angle as a reference, the incident light is reflected at a predetermined reference point. 7. The steering control device for a self-propelled vehicle according to claim 6, further comprising means for identifying that the light is reflected from the means. (8) comprising means for storing only the azimuth of light detected within an angular range set with the predicted azimuth as a reference, and the azimuth stored in the storage means is used as an identification target in the reference point identification azimuth; 7. The steering control device for a self-propelled vehicle according to claim 6, wherein the steering control device handles the steering control device as follows. (9) The steering control device for a self-propelled vehicle according to any one of claims 1 to 8, characterized in that the reference points are provided at at least three force points.