JP2717826B2 - Steering control device for self-propelled vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a steering control device for a self-propelled vehicle, and particularly to a self-propelled vehicle such as an automobile, an unmanned mobile conveyance device in a factory, an agricultural and civil engineering machine, and the like. The present invention relates to a vehicle steering control device.

(Prior Art) Conventionally, as a device for detecting the current position of a moving object such as the self-propelled vehicle, means for scanning a light beam generated by the moving object in a circumferential direction around the moving object; There has been proposed an apparatus which is fixed to at least three places away from the body and includes light reflecting means for reflecting light in the incident direction and light receiving means for receiving light reflected from the light reflecting means (Japanese Patent Application Laid-Open No. H10-163873). Akira
59-67476).

In this technique, an opening angle between three light reflecting means centered on a moving body is detected based on a light receiving signal detected by the light receiving means, and the detected opening angle and a predetermined light reflecting means The position of the moving object is calculated based on the position information.

By the way, in the above system, the light beam cannot be irradiated to the light reflecting means due to the inclination or vibration of the self-propelled vehicle, or the light receiving means receives reflected light from an object other than the light reflecting means. There was a case.

Thus, if the reflected light of the light beam is not reliably received by the light receiving means, the position of the self-propelled vehicle is incorrectly calculated,
As a result, the self-propelled vehicle cannot run along the planned course.

On the other hand, for example, in Japanese Patent Application Laid-Open No. Sho 59-104503, the position detection of a moving object is devised so that the light beam can be reliably irradiated to the light reflecting means by changing the scan speed and scan angle of the light beam. A method has been proposed.

In Japanese Patent Application Laid-Open No. 59-211816, the irradiation light generated by the moving body is intermittent and periodic so that the irradiation light can be distinguished from light from another light source. There has been proposed a moving body position detecting device that has been devised.

(Problems to be Solved by the Invention) However, in any of the above-described technologies, when the optical sensor system such as the light receiving unit fails, the rotary table driving unit that rotates the optical sensor system such as the light receiving unit fails. In this case, there is a further problem that the position of the self-propelled vehicle cannot be detected when all of the light reflecting means serving as a reference for the calculation are in a collapsed state.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a self-propelled vehicle capable of taking measures to prevent the self-propelled vehicle from traveling in the wrong direction even when an unexpected situation such as a failure of the light receiving means occurs. Another object of the present invention is to provide a steering control device.

(Means and Actions for Solving the Problems) In order to solve the above problems and achieve the object, the present invention is based on light signals from at least three reference points detected by light receiving means. In a self-propelled vehicle steering control device configured to detect the self-position of the self-propelled vehicle and perform steering control based on the detection result, the direction of the light reflecting means to be detected in the next scan When the light reflecting means is detected in the predicted azimuth, the position of the self-propelled vehicle is calculated based on the detected azimuth, and when the light reflecting means is not detected in the predicted azimuth, The position of the self-propelled vehicle is calculated by estimating the azimuth of the undetected light reflecting means as the predicted azimuth, and after detecting the optical signal from one of the reference points, Self-propelled if the next light signal is not detected for more than time It is characterized in that it has means for stopping the running of the car.

In the present invention having the above configuration, when the reference point is temporarily lost, the position of the self-propelled vehicle is calculated based on the estimated azimuth of the reference point. If no optical signal from the reference point is detected during the period, the vehicle can be stopped, and the vehicle can be prevented from traveling in the wrong direction.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 6 is a perspective view showing a self-propelled vehicle on which the control device of the present invention is mounted, and an arrangement state of a light reflector disposed in an area where the self-propelled vehicle runs.

In the figure, a self-propelled vehicle 1 is a self-propelled vehicle for agricultural work such as a lawnmower. A rotary table 4 driven by a motor 5 is provided above the self-propelled vehicle 1. The rotary table 4 has a light emitting device 2 for generating a light beam.
And a light receiver 3 for receiving the reflected light of the light beam.

The light emitting device 2 includes a light emitting diode that generates light,
The light receiver 3 includes a photodiode (not shown) for receiving incident light and converting the light into an electric signal. Further, the rotary encoder 7 is provided so as to be linked with the drive shaft of the rotary table 4, and the rotation angle of the rotary table 4 can be detected by counting the pulses output from the rotary encoder 7.

A reflector 6 is provided around the work area of the vehicle 1. The reflector 6 has a reflecting surface that reflects incident light in the incident direction, and is conventionally commercially available.
A so-called corner cube prism can be used.

Next, the configuration of the control device according to the present embodiment will be described with reference to the block diagram shown in FIG. In FIG.
Is scanned in the direction of rotation of the turntable 4 and is reflected by the reflector 6. The light beam reflected by the reflector 6 enters the light receiver 3.

The counter 9 counts the number of pulses output from the rotary encoder 7 as the rotary table 4 rotates. Then, the count value of the pulse is transferred to the identification processing unit 11 each time the light receiver 3 receives the reflected light.

The identification processing unit 11 calculates the azimuth of each reflector 6 with respect to the traveling direction of the self-propelled vehicle 1 based on the count value of the pulse transmitted each time the reflected light is received.

The azimuth angle detected by the identification processing unit 11 is input to the opening angle calculation unit 10 and the opening angle of each reflector 6 viewed from the self-propelled vehicle 1 is calculated.

The position / traveling direction calculation unit 13 calculates the current position coordinates of the vehicle 1 based on the opening angle, and calculates the traveling direction of the vehicle 1 based on the azimuth. The calculation result is input to the comparison unit 25. In the comparison section 25, the traveling course setting section 16
Is compared with the coordinates and traveling direction of the self-propelled vehicle 1 obtained by the position / traveling direction calculation unit 13.

The comparison result is input to the steering unit 14, and a steering motor (not shown) connected to the front wheel 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 is detected by a steering angle sensor 15 provided on the front wheels of the self-propelled vehicle 1 and fed back to the steering unit 14.

The drive unit 18 controls the start / stop of the engine 19 and controls the clutch 20 that transmits the power of the engine 19 to the rear wheels 21.

The light receiving signal from the light receiver 3 is input to the fail detecting means 12. If the next detection signal has not been input even after a predetermined time has elapsed after the input of the previous light receiving signal, a command for stopping the traveling of the self-propelled vehicle (engine stop) is issued to the drive unit 18.

The fail detecting means 12 includes a counter for measuring a clock signal having a predetermined period, and starts counting the clock signal in synchronization with the first light receiving signal input from the light receiver 3, and the counted value is equal to the predetermined value. When the next light-receiving signal is not input until the count reaches, a count end signal is output.
The count end signal is input to the driving unit 18 and the driving unit 18
Outputs an engine stop signal in response to the signal. If the next light receiving signal is input before counting the predetermined value, the count value of the counter is cleared.

On the other hand, the elapse of the scheduled time can also be detected from the traveling distance of the vehicle 1. That is, the distance that the self-propelled vehicle 1 can travel within the scheduled time is set in advance, and the end of the travel of the scheduled travel distance can be regarded as the elapsed time of the scheduled time. Therefore, when the determination for issuing the command to stop the engine of the self-propelled vehicle 1 is made based on the traveling distance,
For example, a means for detecting a planned mileage by a signal similar to a signal input to a known odometer provided as a guide for determining the maintenance time of the self-propelled vehicle is provided, and the vehicle travels by the planned mileage. In the meantime, the failure detecting means 12 may be configured to output the engine stop signal when the next light receiving signal is not input.

The failure detecting means 12 may have any one of the above-described time elapse determining means and the traveling distance judging means. However, the failure detecting means 12 should have both so as to cope with one of the failures. If more desirable.

Note that, of the components shown in FIG. 1, the portion surrounded by a chain line can be constituted by a microcomputer.

The identification processing section 11 has a function of identifying and losing the light reflector 6 based on the azimuth angle, separately from the azimuth angle detection function.

That is, based on the azimuth angle, the azimuth of the light reflector to be detected in the next scan is predicted, and the azimuth of the light emitting source detected in the next scan is scheduled depending on whether or not it matches the predicted azimuth. It is determined whether the light reflector has been detected or lost, and a predetermined process is performed according to the result of the determination.

In the identification processing unit 11, when the light reflector is continuously missed, the traveling of the self-propelled vehicle 1 is stopped on the condition that the number of missing times reaches a predetermined number.

The detailed configuration of the identification processing unit 11 and a specific example of the identification processing by the processing unit are described in Japanese Patent Application No. 63-262192, and the description thereof is omitted here.

FIG. 4 shows the positions of the vehicle 1 and the reflector 6 in a coordinate system for indicating the work range of the vehicle 1.

In FIG. 4, the positions of the reflectors 6 are A, B,
C (hereinafter referred to as reference points A, B, C). In the figure, the positions of the reflectors 6 arranged at three positions are represented by an xy coordinate system having a reference point B as an origin and a line connecting the reference points B and C as an x-axis.

In the figure, the azimuths of the reference points A, B, and C based on the traveling direction of the self-propelled vehicle 1 are indicated by θa, θb, and θc, respectively.
The opening angles between the reference points A and B, B and C viewed from the self-propelled vehicle 1 are indicated by α and β, respectively.

The position T (x, y) and the traveling azimuth θf of the self-propelled vehicle 1 are obtained by a calculation formula based on the principle of triangulation based on the opening angles α and β and the azimuth angles θa, θb and θc. Examples of the calculation formula are described in detail in Japanese Patent Application Nos. 63-116689 and 63-149519.

Next, the steering control for controlling the traveling direction of the self-propelled vehicle 1 based on the position and the traveling direction of the self-propelled vehicle 1 will be described.
FIG. 5 is a diagram showing a positional relationship between a traveling course of the self-propelled vehicle 1 and a reference point, and FIG. 2 is a flowchart of steering control.

FIG. 5 shows the reference point B as the origin and the reference points B and C
The position of the self-propelled vehicle 1 and the work area 22 by the self-propelled vehicle 1 are shown in a coordinate system having a line passing through the x-axis.

The point R (Xret, Yret) indicates the return position of the self-propelled vehicle 1, and the work area 22 has coordinates (Xst, Yst), (Xst, Ye), (Xe, Ys).
t) and an area connecting points indicated by (Xe, Ye). Here, the position T of the self-propelled vehicle 1 is indicated by (Xp, Yp).

Although FIG. 5 shows an example in which the four sides of the work area 22 are parallel to the x-axis or the y-axis for simplicity of description, reference points A, B, and C are provided around the work area 22. Are arranged, the shape of the work area 22 and the directions of the four sides of the work area 22 are arbitrary.

The control procedure will be described with reference to the flowchart of FIG.

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

In step S2, the self-propelled vehicle 1 is stopped
2. Rotate the light receiver 3 to detect each of the reference points A, B, and C, and determine the azimuth of each of the reference points viewed from the self-propelled vehicle 1 by the identification processing unit.
11 is stored in the storage means.

In step S3, Xst is set as the X coordinate Xn of the traveling course, and the traveling course is determined.

 In step S4, the traveling of the self-propelled vehicle 1 is started.

In step S5, it is determined whether or not the light receiver 3 has received the reflected light from the reference point. If the reflected light has not been received, the process proceeds to step S18, and it is determined whether or not a predetermined time has elapsed since the previous detection of the received light signal. Elapse of time is determined by the count value of the counter or the detection value of the traveling distance detecting means.

If the elapsed time has not reached the scheduled time, the process of step S5 is repeated until reflected light is detected. When the reflected light is detected, the process proceeds to step S6, where the identification processing unit 11 performs a reference point identification process.

In step S7, the position (Xp, Yp) of the self-propelled vehicle 1 and the traveling direction θf are calculated.

In step S8, the deviation amount from the traveling course {ΔX (the deviation of the self-propelled vehicle 1 in the x-axis direction) = Xp−Xn, Δθf (the deviation in the traveling direction)} is calculated, and in step S9, the deviation amount is calculated according to the deviation amount. Thus, the steering angle is controlled by the steering unit 14.

In step S10, it is determined whether the self-propelled vehicle 1 is traveling in the y-axis direction away from the origin (outbound direction) or in the direction approaching the origin (return direction).

If it is the direction of the way, it is determined in step S11 whether one stroke has been completed (Yp> Ye), and if it is the return direction, it is determined whether or not one stroke has been completed (Yp <Yst) in step S12. Is determined. In step S11 or S12,
If it is determined that one process has not been completed, the process returns to step S5.

If it is determined in step S11 or S12 that one stroke has been completed, then it is determined in step S13 whether all the strokes have been completed (Xp> Xe).

If the entire process has not been completed, the process moves from step S13 to step S14, and the U-turn control of the self-propelled vehicle 1 is performed.
The U-turn control is different from the steering control of the straight stroke performed by the processing of steps S7 to S9 in which the position information of the self-propelled vehicle 1 calculated by the position / traveling direction calculation unit 13 is fed back to the steering unit 14. It is done in a manner.

That is, in the turning stroke, the self-propelled vehicle 1 travels with the steering angle fixed at a preset angle. 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 falls within a predetermined angle range, the turning is stopped,
The process returns to the steering control of the straight stroke performed by the processes of steps S7 to S9.

In step S13, Xn is set to Xn + L, and the next traveling course is set. If the next traveling course is set, the process returns to step S5, and the above processing is repeated.

When all steps have been completed, return position R (Xret, Yret)
Returning to (Step S16), the traveling is stopped (Step S17).

In step S18, if no light reception signal is detected after the elapse of the scheduled time, a failure such as a failure of the light receiver 3 or the rotary table 4 of the light receiver 3, or a fall of the light reflector occurs. It moves to step S19 and outputs an engine stop command to the drive unit 18,
The self-propelled vehicle 1 stops.

As described above, the failure detecting means 12 can perform processing under microcomputer control.Aside from such software processing, if a backup circuit having a hardware configuration described below is provided, failure detection and Protection can be further ensured.

FIG. 3 shows an example in which a backup circuit is provided in addition to the failure detecting means.

In the figure, an engine stop command signal a output from the fail detecting means 12 and a signal b output from the timer circuit 23 after a set time of the timer circuit 23 have elapsed are:
The signal is input to the OR circuit 24. Therefore, when the signal a or b is input to the OR circuit 24, the OR circuit 24 outputs the engine stop signal c to the drive circuit 18.

The light receiving signal output from the light receiver 3 is input to the fail detecting means 12 and also to the timer circuit 23. When a light receiving signal is input to the timer circuit 23, the transistor Trl becomes conductive, and the capacitor C1 is discharged.

Here, the capacitor C1 and the resistor R1 are added to the timer circuit 23.
If no light receiving signal is input for the time set by the value of ~ R3, the potential of the capacitor C1 rises and the transistor
Tr2 conducts, and accordingly, the transistor Tr3 is turned off. As a result, the signal b input from the timer circuit 23 to the OR circuit 24 changes to high “H”, and the OR circuit 24 outputs the engine stop signal c.

Therefore, while the light receiving signal is frequently input, the transistor Tr2 is conductive, and the input signal b of the OR circuit 24 is low “L”.

As described above, in the present embodiment, the position and the traveling direction of the self-propelled vehicle 1 are calculated based on the signal detected by the light receiver 3, and the calculated result is compared with a preset traveling course. Then, the steering unit 14 is driven so as to correct the deviation amount, and the steering control of the self-propelled vehicle 1 is performed. If no light receiving signal is input from the light receiver 3 to the fail detecting means 12 for a predetermined time or more, the engine is stopped and the traveling of the self-propelled vehicle 1 is stopped. As a result, when the light receiver 3 does not detect any light receiving signal, the self-propelled vehicle 1 does not run off the predetermined course.

In the present embodiment, when the reference point is lost due to the reference point missing processing function in the identification processing unit 11,
The azimuth of the reference point is estimated, and the self-propelled vehicle 1 is estimated based on the estimated value.
Is calculated and steering control is performed. Therefore, a certain amount of time until the scheduled time set in the fail detecting means 12 elapses is determined based on the estimated value.
Is controlled so that the vehicle does not deviate extremely from the planned traveling course. If the time at which the error due to the estimation is expected to be accumulated is set as the scheduled time when set in the failure detecting means, the actual value and the calculated value of the self-position of the self-propelled vehicle 1 are calculated. The traveling of the self-propelled vehicle can be stopped before the deviation increases.

Further, in this embodiment, since the backup circuit is provided in the fail detecting means 12, the traveling of the self-propelled vehicle 1 can be stopped more reliably in response to an unexpected situation.

The backup circuit and the fail detecting means may be used alone as well as in combination with each other.

(Effect of the Invention) As is clear from the above description, even if the reference point is temporarily lost, no actual steering error occurs.
The traveling can be continued, and the traveling can be stopped when no light receiving signal is detected for a predetermined time during the unmanned steering of the self-propelled vehicle. Therefore, even when the optical sensor system such as the light receiving unit and the rotation unit of the optical sensor system such as the light receiving unit break down, and the light reflecting unit falls down,
It is possible to prevent the self-propelled vehicle from running for a long time without being able to detect its own position.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a flowchart of steering control, FIG. 3 is a circuit diagram of a fail detecting means provided with a backup circuit, and FIG. FIG. 5 is a plan view showing an arrangement state of the self-propelled vehicle and the reflector on the traveling course, and FIG. 6 is a perspective view showing an arrangement state of the self-propelled vehicle and the reflector. FIG. DESCRIPTION OF SYMBOLS 1 ... Self-propelled vehicle, 2 ... Light emitting device, 3 ... Light receiving device, 6 ... Reflector, 7 ... Rotary encoder, 9 ... Counter, 10
······························································································ 23

Claims (4)

(57) [Claims] 1. A light beam generated from a self-propelled vehicle is scanned in a circumferential direction around the self-propelled vehicle, and the light beam is reflected from light reflecting means disposed at at least three reference points. In a self-propelled vehicle steering control device that receives reflected light and detects the position of the self-propelled vehicle, based on a light receiving interval of the reflected light from the light reflection unit, Azimuth angle detection means for detecting an azimuth angle, self-propelled vehicle position calculation means for calculating the position of the self-propelled vehicle based on the azimuth angle detected by the azimuth angle detection means, azimuth detected by the azimuth angle detection means Means for predicting the azimuth of the light reflecting means to be detected in the next scan based on the angle; and when the light reflecting means is detected in the predicted azimuth, the position of the self-propelled vehicle based on the detected azimuth. The calculation means calculates the position of the self-propelled vehicle, and If the light reflecting means is not detected in the position, the azimuth of the light reflecting means not detected is estimated to be the predicted azimuth, and the position of the self-propelled vehicle is calculated by the self-propelled vehicle position calculating means. After detecting an optical signal from one of the light reflecting means, if the next optical signal is not detected for a predetermined time or more, it is possible to prevent accumulation of azimuth errors due to the estimation. Means for stopping the traveling of the self-propelled vehicle as much as possible. 2. The self-propelled vehicle steering control device according to claim 1, wherein the elapse of the predetermined time is detected by a count value of a clock signal by a counter. 3. The steering control device for a self-propelled vehicle according to claim 1, wherein the elapse of the predetermined time is detected by traveling the self-propelled vehicle for a predetermined distance. 4. The self-propelled vehicle steering control device according to claim 1, wherein the elapse of the predetermined time is detected by a timer circuit including a time constant circuit composed of a resistor and a capacitor.