JPH03291702A - Steering controller for self-travelling vehicle - Google Patents

Abstract

PURPOSE:To prevent a self-travelling vehicle from meandering even when a reference point is missed by fixing a steering angle to a straight driving state while responding to a missed signal in the case of missing a reflector when predictively calculating the azimuth of a reflector by receiving reflected light from a reflector arranged at the reference point. CONSTITUTION:When the reflector provided at the reference point on a road or the like is turned, the turn is scanned by light emitter and receivers 2 and 3, and the output of a rotary encoder 7 is counted by a counter 9. Then, the azimuth of the reflector to the travelling direction of the vehicle is detected by an azimuth detection part 11 and stored into an azimuth memory 12. Based on this stored content, an azimuth identification part 24 identifies the azimuth and based on this identified result, and azimuth predictive calculation part 27 predicts the next reflector azimuth. Then, the steering or the like of the vehicle is corrected. In such a case, when the reflector is missed, a missed signal 1 is outputted from the identification part 24, and passed through a switching signal generation part 32 and a changeover switch 33, and the steering angle is fixed to the straight driving state by an angle set part 30 for straight drive. Thus, the vehicle can be straightly drive to a designated turning point while being prevented from meandering.

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 equipped with a light reflecting means that is fixed at at least three locations apart from the light reflecting means in the direction of incidence, and a light receiving means that receives the reflected light from the light reflecting means. 59
-67476).

The device detects the opening angle between the three light reflecting means as seen from the moving body based on the light receiving output of the light receiving means, and detects the opening angle between the detected opening angle and each preset light reflection means. The moving object position is calculated based on the position information of the means.

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

On the other hand, if light reflecting means are installed at four locations and one of them is temporarily lost, the self-position is calculated based on the positions of the other three light reflecting means, The direction of the light reflecting means can be calculated backwards from the calculation result (Japanese Patent Application No. 1-1868).

In addition, if the light reflecting means is set at only three locations, the light receiving direction in which the light reflecting means should be detected next is predicted based on the data of the light receiving direction of the light reflecting means detected in the past. , the light reception signal detected in the predicted direction,
It is also possible to distinguish the light from reflected light from other objects and determine that the light is coming from the intended light reflecting means. According to this method, if a received light signal is not detected in the predicted direction,
By using the predicted direction as is as reflected light from the scheduled light reflecting means to calculate the self-position of the self-propelled vehicle, it is possible to solve problems caused by temporary loss of sight of the light reflecting means.

(Problems to be Solved by the Invention) According to the above-mentioned prior art, even if a self-propelled vehicle temporarily loses sight of the light reflecting means arranged at the reference point, it is possible for the self-propelled vehicle to significantly deviate from the planned travel course. do not have. However, as mentioned above, the position of the self-propelled vehicle calculated based on the position data of the light reflection means obtained by back calculation or the position data of the light reflection means obtained from the estimated azimuth data is not necessarily accurate. Yes, it's difficult. As a result, when feedback steering control is performed based on the position data of the self-propelled vehicle, this may cause the self-propelled vehicle to wander (meander).

On the other hand, in a driving mode in which the self-propelled vehicle travels in a straight line, then passes through a turning process at the end of the running area and then transitions to the next straight process adjacent to the straight process, the transition occurs from the straight process to the turning process. When doing so, if the turning point is not properly observed, the vehicle will deviate from the driving work area, so it is necessary to give accurate turning instructions.

An object of the present invention is to solve the problems of the prior art described in item 2, to prevent a self-propelled vehicle from meandering even when it temporarily loses sight of the light reflecting means, and to An object of the present invention is to provide a steering control device for a self-propelled vehicle that enables the self-propelled vehicle to reliably transition from a straight stroke to a turning stroke when traveling on a travel course consisting of:

(Means and Effects for Solving the Problems) In order to solve the above-mentioned problems and achieve the objects, the present invention aims to direct a light beam generated by a self-propelled vehicle in a circumferential direction around the self-propelled vehicle. means for scanning, and means for receiving the reflected light of the light beam from the light reflecting means disposed at a reference point distant from the self-propelled vehicle to measure the azimuth of the light reflecting means as seen from the self-propelled vehicle. , means for driving the self-propelled vehicle based on the azimuth angle; means for predicting the azimuth angle at which each light reflecting means should be detected in the next scan based on the measured azimuth angle; The first feature is that the vehicle is further provided with means for fixing the steering angle to a straight-ahead state when the light reflecting means cannot be detected at the predicted azimuth.

In addition, the present invention estimates the azimuth of the lost light reflecting means when the light reflecting means cannot be detected at the predicted azimuth angle while traveling straight, and detects the estimated azimuth and other detected azimuths. The means for calculating the position of the self-propelled vehicle based on the azimuth angle of the light reflecting means determined by The second feature is that the self-propelled vehicle is provided with means for detecting that the self-propelled vehicle has reached a position where it should transition from the stroke to the turning stroke that follows, and means for causing the self-propelled vehicle to turn in response to the output of the detection means. It has the characteristics of

” In the present invention having the configuration described in the above, when the reference point is lost,
If the vehicle is traveling straight ahead from that point, steering angle control is not performed to correct the deviation in the position and direction of travel of the self-propelled vehicle. However, even in this case, the position detection of the self-propelled vehicle is continued based on the estimated azimuth of the lost reference point. Then, it is possible to determine that the self-propelled vehicle has reached the turning stroke starting point based on the position information in the traveling direction of the position information of the self-propelled vehicle, and to make the self-propelled vehicle turn.

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

FIG. 9 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. A rotary table 4 driven by a motor 5 is provided on the top of the self-propelled vehicle 1.

The rotary table 4 includes a light emitter 2 that generates a light beam 2E.
A light receiver 3 is mounted to receive the reflected light 2R of the light beam.

The light emitter 2 includes a light emitting diode for generating a light beam 2E, and the light receiver 3 includes a photodiode for receiving reflected light 2R and converting it into an electrical signal (both not shown). Further, the rotary encoder 7 is provided so as to be interlocked with the drive shaft of the rotary table 4, and by counting the pulses output from the rotary encoder 7, the rotation angle of the rotary table 4 can be detected.

Reflectors 6a to 6c are arranged around the work area of the self-propelled vehicle 1. The reflectors 6a to 6c are provided with reflective surfaces that reflect incident light in the direction of incidence, and a known light reflecting means such as a so-called corner cube prism can be used.

With the above configuration, the light beam 2E generated by the light emitter 2
is scanned, for example, in a counterclockwise direction, and the reflected light 2R from the reflectors 6a to 6c is reflected by the reflectors 6a and 6b.

The reflected light from 6c is sequentially detected by the light receiver 3, and based on the detection signal, the self-position of the self-propelled vehicle 1 with respect to the reflectors 6a to 6c is detected and steering control is performed.

By the way, there is a possibility that there is a reflective object or a light-emitting object other than the reflector in or near the driving area of the self-propelled vehicle 1, and the light receiver 3 may detect the light from this reflective object. It is possible that the reflected light from the reflector cannot be detected.

In addition, in this embodiment, whether or not the detected light is from a scheduled reflector is determined by the following process.

FIG. 3 is an explanatory diagram of the reference point identification process. In the figure, the reflector 6 is located at the reference point A-C around the work area 22.
a to 6c are arranged respectively.

An arrow 29 indicates the scanning direction of the light beam emitted from the self-propelled vehicle 1.

In the illustrated arrangement, the self-propelled vehicle 1 calculates the azimuth angle of each reference point as seen from the self-propelled vehicle 1 based on the detection signal of the light receiver 3, and further calculates the azimuth angle of each reference point as seen from the self-propelled vehicle 1 based on the detection signal of the light receiver 3. Based on the angle, the azimuth angle of the reference point to be detected in the next scan is predicted.

The predicted azimuth angle (predicted azimuth angle) is the angle θpa to θpc
Indicated by The reference point identification azimuth p is set in the azimuth in which scanning has advanced by an angle θh in the light beam scanning direction from each predicted azimuth θpa to θpc.
A-PC is provided. This reference point identification direction pa-pc
Each time the light beam scans, the incident light from the direction closest to the predicted azimuth among the lights detected from the previous reference point identification azimuth to the current reference point identification azimuth is set at the scheduled reference point. It is determined that the light is from a reflected reflector.

For example, assume that in the reference point identification direction pa, light from the noise sources Nl, N2 and the reflector 6a installed at the reference point A has been detected from the previous reference point identification direction pc to the present. In this case, the predicted azimuth θpa is selected from among these lights.
Light from the direction closest to , that is, light from reference point A can be identified.

Furthermore, the following process can be added to improve the accuracy of identifying reference points. In other words, a predetermined range (an angle equal to or smaller than the angle θh) is set before and after the predicted azimuth, and even if the light is from the direction closest to the predicted azimuth, if it 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, the predicted azimuth angle is used to calculate the position of the self-propelled vehicle 1 in the processing cycle while traveling in a straight line on the driving course, and the predicted azimuth angle or the The angle obtained by adding the planned angle to the predicted azimuth is 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. Figures 6 and 7 show the self-propelled vehicle 1.
1 shows the positions of the self-propelled vehicle 1 and the reflector 6 in a coordinate system for indicating the working range of the vehicle.

In FIGS. 6 and 7, the reference points A, B, and C where the reflectors 6a to 6C are arranged, and the position of the self-propelled vehicle 1 are based on reference points B and C, with reference point B as the origin.
It is expressed in an x-y coordinate system with the straight line connecting them as the X axis.

As can be understood from the figure, the position T of the self-propelled vehicle 1 exists on the circumcircle of the triangle ATB and at the same time on the circumcircle of the triangle BTC. Therefore, the position of the self-propelled vehicle 1 is determined by calculating the two intersections of the circumscribed circles Q and P of the triangle ATB and the triangle BTC, respectively.

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.

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. 7th
In the figure, the angle between the traveling direction of the self-propelled vehicle 1 and the X axis is θf, and reference points A, B,
When the azimuth angle of C is θa, θb, θC, θf- 360°-tan' (y/ (xc-x) 1θC
...(L) becomes.

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 two calculation formulas and the above 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. 8 is a diagram showing the positional relationship between the traveling 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 the coordinates (Xs t, Ys t), (XstYe),
This is an area or work area 22 connected by points indicated by (Xe, Yst) and (Xe, Ye).

The position T of the self-propelled vehicle 1 is indicated by coordinates (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 turning start point in the forward direction (two directions on the drawing) and the turning start point in the return direction (downward on the drawing) are the y coordinates Y.
It is shown as e and Yst. That is, while the self-propelled vehicle 1 is traveling straight, turning is started when the y-coordinate of the self-propelled vehicle 1 reaches Ye or Yst.

Whether the y-coordinate of the turning end point is the same as the y-coordinate of the turning start point, or whether the self-propelled vehicle 1 has reached the turning end point, since the coordinates of the self-propelled vehicle 1 cannot be calculated accurately while turning. The judgment is
This is not done based on the y-coordinate of the self-propelled vehicle 1, but based on the azimuth data of the reference point as seen from the self-propelled vehicle 1.

Examples of steering control during a turning stroke and control for determining the end of a turn are disclosed in Japanese Patent Application Laid-Open No. 1-316808 and Japanese Patent Application No. 2-19293.
listed in the number.

In addition, in FIG. 8, in order to simplify the explanation, an example is shown in which the four sides of the work area 22 are y-axis or parallel to the y-axis, but there are reference points A, B, and C around the work area 22. , the shape of the work area 22 and the work area 2
The orientation of the four sides of 2 is arbitrary.

Next, with reference to the block diagram shown in FIG. 1, the functional configuration of the control device for performing the steering control described in "-5" will be explained. In the figure, the part surrounded by chain lines can be constructed by a microcomputer.

In FIG. 1, a light beam 2E emitted from a light emitter 2
is scanned in the rotating direction of the rotary table 4 and reflected by the reflector 6 (6a to 6c). The reflector 6a~
The reflected light 2R of 6C is received by the light receiver 3.

The counter 9 counts pulses output from the rotary encoder 7 as the rotary table 4 rotates. The count value of the pulse is transferred to the azimuth detecting section 11 every time the light receiver 3 detects light. The azimuth detector 11 calculates the azimuths of the deflectors 6a to 6C based on the number of supplied pulses.

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.

6 The identification timing signal is set at the time when the scanning progresses 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, that is, at the reference point identification azimuth pa-pc. It is output when the scanning of the light beam progresses. For this purpose, the identification timing generator 23
Then, when the output pulses of the rotary encoder 7 are taken in for a scheduled number of times corresponding to the predicted azimuth calculated by the azimuth prediction calculating section 27, 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.

Note that if the azimuth angle identification unit 24 does not detect the scheduled reference point, a lost sight signal a is output.

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 6a to 6C 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 comparison section 25.

The comparison unit 25 compares the data representing the travel course set in the travel course setting unit 16 with the position (Xp, Yp) and traveling direction θf of the self-propelled vehicle 1 obtained by the position/direction calculation unit 13. be compared.

The results of this comparison, that is, the amount of deviation ΔX in the X direction and the angle of deviation Δθ from the planned travel course are input to the steering unit 14 via the switching unit 33 .

In addition to the signal from the comparison section 25, the steering section 14 also receives a signal from the switching section 3.
Steering angle fixing angle data is supplied from the straight-ahead angle setting section 30 and the turning angle setting section 31 according to the switching position No. 3. In the straight-ahead angle setting section 30, "0°" is set as the deviation angle Δθ in order to fix the steering angle for straight-ahead travel. Further, in order to fix the steering angle for turning, a large deviation angle is set in the turning angle setting section 31 as the deviation angle Δθ. By doing so, the steering unit 14 selects the largest possible steering angle in an attempt to correct the large sliding angle.

The comparison unit 25 determines whether or not the self-propelled vehicle 1 is at the position where it should turn based on the y-coordinate Yp of the self-propelled vehicle 1, and if the self-propelled vehicle 1 is at the position where it should turn, the turning distance is determined. The detection signal S is set to a high level "H", and when the detection signal S is present in a straight-line process, the turning section detection signal S is set to a low level "L". The loss of sight signal a and the turning stroke detection signal S are supplied to the switching signal generating section 32. The switching signal generating section 32 outputs a switching signal 0 by performing the following logical operation.

9 When the turning stroke detection signal Suga is “L”, the azimuth angle identification unit 24
When the loss of sight signal a is "H", that is, when the reference point is lost while traveling straight, a switching signal C is output that connects the switching unit 33 to the straight angle setting unit 30 and the steering unit 14. be done. Further, when the turning stroke detection signal is "H", that is, while the self-propelled vehicle 1 is in the position where it should turn, the switching section 33 is connected to the turning angle setting section 31 and the steering section 14. A switching signal C is output. Furthermore, if the loss of sight signal a is "L" and the turning section detection signal is "L", if the user is traveling straight without losing sight of the reference point, the comparison unit 25
A switching signal for connecting the steering section 14 and the steering section 14 is output.

The steering section 14 receives the deviation amount ΔX supplied from the comparison section 25.
and the deviation angle Δθ, and the steering motor 28 connected to the front wheels 17 of the self-propelled vehicle based on the angle data supplied from the straight-ahead angle setting section 30 and the turning angle setting section 31.
to drive. 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 is fed back to the steering front section 14. The drive control unit 18 controls starting and stopping of the engine 19 and the operation of a clutch 20 that transmits the power of the engine 19 to the rear wheels 21.

Furthermore, in order to improve the identification accuracy of reference points, the following functions can be added. That is, range setting section 2
A value indicating the angular range set in 6 is supplied to the azimuth angle identification unit 24, and it is determined whether the light detected in the direction closest to the predicted azimuth is detected in the planned angular range. Functions are added.

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, and if it is outside the planned range. , the aperture angle is calculated using the predicted azimuth calculated by the azimuth angle prediction calculation unit 27.

Either the light from within the range set in the range setting unit 26 is judged as reflected light from the scheduled reference point and the aperture angle is calculated using the azimuth of the destination, or the azimuth of the incident light is Whether the opening angle is calculated using the azimuth determined without determining whether it is within the range set in the range setting unit 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 required.

The control procedure will be explained according to flowchart 1 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 1 starts running.

In step S4, it is determined whether the light receiver 3 has received light from the reference point or another light source. When light is detected, the process proceeds to step S5, where a light reception process described below is performed.
If no light is detected, the process advances 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 reflected lights is from the scheduled reference point. This judgment is based on the predicted azimuth angle θp calculated by the azimuth angle prediction calculation unit 27.
This is performed depending on whether scanning has progressed to the reference point identification azimuth pa-pC, which is a predetermined angle θh from a to θpe.

Steps 84 to S until the judgment in step S6 is affirmative
Step 6 is repeated, and if the determination is affirmative, the process proceeds to step S7, where a reference point identification process is executed.

In step S8, it is determined by the reference point identification process whether the scheduled reference point, that is, the reference point whose azimuth is used to calculate the position of the self-propelled vehicle, has been detected or lost. This determination follows a reference point lost flag set in reference point processing to be described later.

If the reference point is detected, the process advances to step S9, and the position T (X
p, Yp) and the traveling direction θf are calculated.

In step SIO, the amount of deviation from the driving course (ΔX=
Xp-Xn, Δθf) is calculated, and in step 811, steering angle control is performed in the three steering sections 14 according to the calculated deviation amount.

In step S12, it is determined whether the self-propelled vehicle 1 is traveling in the y-axis direction in a direction away from the origin (going direction) or in a direction approaching the origin (returning direction).

If it is the forward direction, it is determined in step S13 whether the -stroke has ended (Yp>Ye); if it is the return direction, it is determined in step S14 whether the -stroke has ended (Yp>Ye).
<Ys t) is determined. Step S13
Alternatively, if it is determined in S14 that the -stroke has not been completed, the process returns to step S4.

If it is determined in step S13 or S14 that the -stroke has ended, then in step S15 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 S15 to step 316, and the U-turn control of the self-propelled vehicle 1 is performed. The U-turn control includes steps 89 to S in which position information 4 of the self-propelled vehicle 1 calculated by the position/direction calculation unit 13 is fed back to the steering unit 14.
This is performed in a different manner from the straight-line steering control performed in step 11.

That is, in the turning stroke, the vehicle travels with the steering angle fixed at the angle determined by the steering section 14 based on the angle set by the turning angle setting section 31. Then, when at least one of the azimuth angles of each of the reference points A, B, and C with respect to the self-propelled vehicle 1 matches the planned angle or falls within the planned angle range, the fixation of the steering angle for turning is released. .

In step S17, Xn+ is set to Xn, and the traveling course for the next stroke is set. Once the driving course is set, the process returns to step S4 and the above process is repeated.

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

Yret) (step 518), and the traveling is stopped (step 519).

On the other hand, if it is determined in step S8 that the reference point has been lost, the process moves to step S20 and only the y-coordinate of the self-propelled vehicle 1 is calculated.

The y-coordinate is used as data when determining whether the self-propelled vehicle 1 has reached the turning position in steps S13 and S14.

In step S21, the steering angle is fixed at the angle determined by the steering section 14 based on the angle set by the straight-ahead angle setting section 30. That is, the self-propelled vehicle 1 is fixed in a straight-ahead state.

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 same 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.

Flowchart 1 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 570, 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 reference point B, and pole counter "3" corresponds to reference point C, respectively.

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

In step 571, the light reception flag is determined. If the light reception flag is "1", the process advances to step S72, and if the light reception flag is "0", the process jumps to step S80.

In step S72, the predicted azimuth θpn (since the pole counter is set to “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" or more, that is, whether a plurality of azimuths are stored in the azimuth storage section 12.

If the determination in step S73 is affirmative, it is assumed that one or more noises have been detected, and the process moves to step S74, in which 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 determination 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 with n (predicted azimuth 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 S79, where the same noise as in step S74 is detected. Perform process 8.

After the noise processing, the process proceeds to step S80, where the predicted azimuth angle θpn (predicted azimuth angle θpa
) is set as the azimuth angle θn (θa) of the scheduled reference point.

In step S81, a lost sight n flag (lost sight A flag because the pole counter is "1") indicating that the reference point has been lost is set.

On the other hand, if the difference 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 angle θS determined in this process,
The predicted azimuth at which the same reference point should be detected during the next processing is calculated using the calculation formula (θs+(θS−θn)).

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

In step S78, a lost n flag indicating that the reference point n has been lost is cleared.

9 14- 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 "3" or not. The error value "3" is the number of installed reference points, and the error value is set according to the number n of installed reference points.

If the number of installed reference points matches the pole counter, that is, if it is determined that the identification process has been completed for all reference points, the pole counter is set to "0" in step 386. Returning to the process shown in FIG.

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 corresponding to the pole counter 0 "2" is identified.

Thereafter, identification processing for the reference point C is also performed in the same manner.

As described above, in this embodiment, when a plurality of lights are detected by the light receiver 3, among the plurality of lights, the light from the direction closest to the predicted azimuth angle, and Light from a direction that does not deviate from the predicted azimuth by more than a predetermined angle is determined to be reflected light from a predetermined reference point.

If the vehicle loses sight of a scheduled reference point (a reference point used for position calculation) while traveling straight, the vehicle is driven with the steering angle fixed to the straight state.

In addition, when the scheduled reference point is lost, the predicted azimuth is estimated to be the azimuth of the lost reference point, and the calculation of the position of the self-propelled vehicle 1 is continued using the azimuth. did. Therefore, even if the planned reference point is lost, the position at which the vehicle should proceed to the turning stroke can be almost accurately detected.

(Effects of the Invention) 1 As is clear from the above description, according to the present invention, the following effects can be obtained.

(1) Even if the vehicle temporarily loses sight of the reference point while traveling straight, the steering angle is fixed 17 to the straight traveling state, so the degree of meandering during straight travel can be reduced.

(2) Even if the reference point is temporarily lost, it is possible to proceed to the turning stroke at the planned position. Furthermore, when the vehicle turns with the steering angle fixed at a predetermined angle, it is possible to smoothly transition to the next straight stroke after the turn is completed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the functions of an embodiment of the present invention, Fig. 2 is a flowchart 1 of steering control, Fig. 3 is an explanatory diagram of reference point identification processing, and Fig. 4 is an illustration of reference point identification processing. 5 is a flowchart 1 of the light reception process, FIG. 6 is an explanatory diagram of the principle of detecting the position of a self-propelled vehicle, FIG. 7 is an explanatory diagram of the principle of detecting the traveling direction of a self-propelled vehicle, and FIG. FIG. 9 is a perspective view showing the traveling course of the self-propelled vehicle and the arrangement of the reflectors. 2 1... Self-propelled vehicle, 2... Emitter, 3... Light receiver, 6
゜6a-6C...Reflector, 11...Azimuth angle detection unit,
DESCRIPTION OF SYMBOLS 12... Azimuth storage part, 13... Position/progressing direction calculation part, 23... Identification timing generation part, 24... Azimuth angle identification part, 30... Straight ahead angle setting part, 31.・・・
Turning angle setting part

Claims (4)

[Claims] (1) A light beam generated by a self-propelled vehicle is scanned in a circumferential direction centering on the self-propelled vehicle, and the light beam is reflected from light reflecting means arranged at a plurality of reference points distant from the self-propelled vehicle. A system for receiving reflected light and measuring the azimuth angle of the light reflecting means as seen from the self-propelled vehicle, and based on the results, for causing the self-propelled vehicle to travel on a traveling course consisting of a straight course and a turning course continuous thereto. The steering control device includes: an azimuth angle prediction unit that calculates an azimuth angle at which each light reflecting unit should be detected in the next scan based on the detected azimuth angle; The vehicle is equipped with a reference point identifying means for outputting a lost signal when the vehicle has lost sight of the intended light reflecting means, and a means for fixing a steering angle to a straight-ahead state in response to the lost-of-sight signal while the vehicle is traveling straight. A steering control device for a self-propelled vehicle characterized by: (2) means for estimating the azimuth of the lost light reflecting means in response to the lost sight signal, and the position of the self-propelled vehicle based on the estimated azimuth and the azimuth of other detected light reflecting means; and a means for calculating the position information of the self-propelled vehicle based on the calculated position information of the self-propelled vehicle, and by comparing the position of the self-propelled vehicle in the forward direction of the straight travel process based on the calculated position information of the self-propelled vehicle, the self-propelled vehicle has reached a position where it should proceed to the turning stroke. 2. The self-propelled vehicle according to claim 1, further comprising means for detecting this, and means for causing the self-propelled vehicle to turn by canceling the straight-ahead state of the steering angle in response to the output of the detection means. steering control device. (3) The steering control device for a self-propelled vehicle according to claim 2, wherein the azimuth of the lost light reflecting means is estimated to be the predicted azimuth. (4) The reference point identification means sets a reference point identification direction for each direction in which the scanning of the light beam has progressed by a predetermined angle from the predicted azimuth of each light reflecting means, and Of the incident light detected up to the current reference point identification azimuth, the incident light from the angle closest to the predicted azimuth is determined to be reflected light from the light reflecting means placed at the planned reference point. The steering control device for a self-propelled vehicle according to claim 1, 2 or 3, wherein the steering control device is a means.