JPH0240494Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention corresponds to the direction to be detected by sensing the earth's magnetism in order to detect the running direction of the vehicle body.
In addition, regarding a traveling vehicle equipped with a direction sensor that outputs a pair of voltage signals having a 90 degree phase difference, it is particularly suitable for an unmanned vehicle that the applicant has already proposed in Japanese Patent Application No. 121564/1983. The present invention relates to a traveling vehicle equipped with available direction detection means.

Conventionally, in this type of traveling vehicle, especially in an automobile traveling vehicle configured to perform at least a part of the traveling control automatically, it is necessary to detect the direction in which the vehicle is traveling, so it is possible to detect all directions. It is considered that a geomagnetic sensor can be used as a direction sensor.

However, although the geomagnetic sensor described above is capable of detecting all directions of 360 degrees, in order to do so, the detection direction must be determined based on the values of both of a pair of signals having a 90 degree phase difference. When sampling the azimuth information necessary for the teaching/playback control of unmanned vehicles, which has already been proposed, the signal processing of the sampled data becomes complicated, and the amount of memory used to store the data increases. There was an inconvenience.

In addition, as shown in FIG. 2B, which is a drawing for explaining this embodiment described later, the geomagnetic sensor is arranged in directions where the amount of change in the detected voltages Vx and Vy is small (for example, in the east and west directions for voltage Vx). In this case, the detection error becomes large, so that in order to accurately detect the direction, the direction must be determined using the pair of detection voltages Vx and Vy.

The present invention has been developed in view of the above-mentioned circumstances, and its purpose is to simplify the signals and improve accuracy when determining the direction based on a pair of voltage signals output from the direction sensor. To provide a running vehicle equipped with a means for accurately determining direction.

In order to achieve the above object, a traveling vehicle according to the present invention has the above-mentioned structure, (a) inputs the pair of voltage signals from the azimuth sensor, and connects the azimuth sensor around the vertical axis. A control device that outputs a signal to rotate the camera is linked to the orientation sensor.

(b) The orientation sensor includes an angle detection device that detects a rotation angle around the vertical axis.

(c) The control device includes forced rotation signal output means for outputting a signal to rotate the orientation sensor 360 degrees around the vertical axis.

(d) The control device controls the direction sensor as described in (c) above.
During rotation, the pair of voltage signals detected at every predetermined angle are sampled, and based on the sampling results, one of the pair of voltage signals and the average of the maximum and minimum of this one voltage signal are determined. By comparing the two voltage signals and determining whether or not the one voltage signal output corresponding to the direction exceeds the average value, the other of the pair of voltage signals output corresponding to the direction is determined to be positive. Alternatively, the vehicle is provided with an azimuth signal calculation means that adds a negative sign to obtain an azimuth signal in the traveling direction.

(E) A switching means is provided for switching which of the pair of voltage signals is selected as the one and the other.

The characteristic configuration is that it has the configurations (a) to (e) above.

The effects of this characteristic configuration are as follows. The effect will be explained in the second example of the example below.
The explanation will be based on Figure B.

In other words, if you rotate the orientation sensor 360 degrees,
As shown in the figure, two voltage signals Vx whose phases differ by 90 degrees,
Vy output is obtained. If one of the voltage signals Vy is used to sign positive or negative, it is determined to be positive because it is greater than or equal to the average value Yp between the southeast, and it is determined to be negative because it is less than or equal to the average value Yp between the southeast and the southwest. This positive/negative sign and the other voltage signal output corresponding to the direction
For example, the other voltage signal Vx will be the same between the southeast and southwest areas, but
After determining whether the range is in the southeast or southwest by referring to the positive and negative signs, the accurate direction is detected based on the magnitude of the other voltage signal Vx. It is similarly detected between the north-west and the north-east. Therefore, when driving mainly in the east-west direction, the voltage signal
By using Vy as a sign signal, the direction of travel can be detected with high accuracy. On the other hand, when driving mainly in the north-south direction, the switching means selects the voltage signal Vx as the signal for coding.
The direction of travel can be detected with high accuracy.

As a result of the above, the running direction can be determined 360 degrees from only one type of voltage signal with a subtitle in which coded information of one of a pair of voltage signals is added to the other voltage signal, and the running direction can be determined 360 degrees from the pair of voltage signals. When converting to a signal corresponding to one type of detected orientation with a number, it is possible to arbitrarily select which side of the signal to encode, reducing the amount of signal processing data needed to determine the direction of travel. As a result, the amount of memory required for sampling and storage can be significantly reduced without compromising detection accuracy.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a lawn mower 4 is suspended between the front and rear wheels 2 and 3 of the vehicle body 1 so as to be movable up and down, and the direction of travel is detected by sensing the earth's magnetic field in front of the vehicle body 1. A directional sensor 5 is provided at the rear of the vehicle body 1, and a fifth wheel is provided as a distance sensor 6 for continuously detecting the moving distance of the vehicle body 1, thereby configuring a lawn mowing work vehicle as a traveling vehicle that can run unmanned. .

As shown in FIG. 2A, the orientation sensor 5 has a toroidal core 7 provided with an excitation coil _C0 ,
Output coils Cx and Cy are wound diametrically orthogonally to each other from above, and when an external magnetic field (earth's magnetism) is applied to the toroidal core 7, which has an alternating current flowing through the excitation coil _C0 , the output coils Cx and Cy It is configured to generate an alternating current signal voltage proportional to this external magnetic field. The AC signal voltages generated in the output coils Cx and Cy are amplified to a predetermined level and then converted into DC voltages Vx and Vy as shown in FIG. 2B and output.

By the way, regarding the pair of voltages Vx and Vy, as is clear from Figure 2 (b), one voltage Vx has a small amount of change in the east and west directions, and the other voltage Vy has a small amount of change in the south and north directions. Therefore, depending on whether the direction to be detected is east/west or south/north,
It is configured such that it is possible to select which side of the voltage signals Vx and Vy to encode by means described later.

The toroidal core 7 constituting the orientation sensor 5 is provided with a rotation mechanism A that can freely rotate 360 degrees around the vertical axis P, and the output coil Cx,
In addition to correcting the detected magnetic sensitivity difference with respect to the direction of Cy, it is also configured to be able to detect the relative direction of travel of the vehicle body 1 with respect to a predetermined direction.

The rotation mechanism A is constructed by fixing the toroidal core 7 to a non-magnetic bracket 8, and installing a motor 9 to freely rotate the bracket 8 in the left and right directions, and a sensor rotation angle for detecting the rotation angle θ. A potentiometer PM is provided on the axis P as a detection device.

On the other hand, the distance sensor 6 generates one pulse for each unit movement distance of the vehicle body 1, and counts this pulse a predetermined number of times by the counter 10 to detect a predetermined movement distance _l0 . It is configured.

Then, based on each detection signal of the direction sensor 5 and the distance sensor 6 configured as above, the vehicle body 1
It determines the direction of travel of the vehicle.

Hereinafter, the means for selecting the voltage signals Vx and Vy to be encoded and the means for sampling the voltage signals Vx and Vy will be explained.

As shown in FIG. 3, a pair of voltage signals Vx, Vy corresponding to the detected orientation from the orientation sensor 5
is configured such that its relationship with respect to the control device 11 can be reversed by a changeover switch SW, and after being switched by this switch SW, the DC voltage Vx, which is the orientation detection signal from the orientation sensor 5,
The voltage V ₀ as sensor rotation angle from Vy and potentiometer PM is determined by signal selector 1
2, the signal is converted into a digital signal by the A/D converter 13, and then sent to the input/output interface 14.
The signal is input to the arithmetic unit 15 of the control device 11 via. Then, every predetermined number of pulses from the distance sensor 6 counted by the counter 10 (corresponding to the predetermined moving distance l ₀ ), the direction sensor 5
Voltage Vx as azimuth information detected by
By sampling Vy and using the means described below,
For example, one voltage Vy is encoded, and the other voltage is added with information about this encoded voltage Vy.
Memory 1 uses Vx value as sampling data Xn
It is configured to sequentially store data in six predetermined address areas.

By the way, as mentioned above, the predetermined moving distance l ₀
Before each azimuth sampling, the detection sensitivity for all directions of the earth's magnetic field detected by the azimuth sensor 5 is corrected, and the detected absolute azimuth is adjusted relative to the vehicle body 1 with respect to a predetermined direction of the work area. In order to sample by changing the azimuth of the running direction,
Prior to this sampling, when the vehicle body is stopped, the orientation sensor 5 is rotated 360 degrees in advance, and the detected voltages Vx and Vy detected at every predetermined angle θp are sampled to pattern the detected voltages Vx and Vy at the reference orientation. However, when storing the sampling data Xn and Yn in this detection voltage pattern check, one voltage Vy is compared with the average value Yp described later and encoded (±).
This sign (±) is added to the other voltage Vn, and only one signed data Xn is finally stored as azimuth information. The direction is determined based on the size of this signed data Xn and its sign (±)
Memory 1
6 can be used in a very small amount. That is, the motor 9 is rotationally driven by a signal from a forced rotation signal output means provided in the control device 11 to rotate the orientation sensor 5 by 360 degrees around the vertical axis P, and the control device 11 also rotates the orientation sensor 5 by 360 degrees around the vertical axis P. During the 360 degree rotation, the pair of voltage signals Vx and Vy detected at every predetermined angle θp are sampled, and based on the sampling results, one of the pair of voltage signals Vx and Vy and this By comparing the maximum and minimum average value Yp of one voltage signal and determining whether or not the one voltage signal output corresponding to the azimuth exceeds the average value Yp, The pair of output voltage signals Vx,
The vehicle is provided with an azimuth signal calculation means for obtaining an azimuth signal in the traveling direction by loading the other side of Vy with a positive or negative sign.

Incidentally, FIG. 4 is a flowchart showing the operation of the control device 11 when the orientation sensor 5 described above is rotated 360 degrees in advance to sample the orientation.
Other symbols used in FIG. 4 are control flags.

Further, even when sampling the detected orientation during actual driving, the pair of detected voltages Vx and Vy of the orientation sensor 5 can be similarly stored as a type of signed data by the above-mentioned means.

In this way, the control device 11 converts the signal Yn corresponding to one of the pair of voltage signals Vx and Vy arbitrarily switched by the switch SW to the above-mentioned average value Yp shown in FIG. , encode (±) based on the comparison result, and encode the other signal.
This sign (±) is added to Xn, and one of the pair of voltages Vx and Vy is sampled as signed orientation data to determine the orientation of the vehicle body 1.

In addition, each contact point S ₁ , S ₂ , S ₃ , S ₄ of the switch SW
The contacts S ₁ and S ₄ and the contacts S ₂ and S ₃ are interlocked, respectively,
The structure is such that when contacts S ₁ and S ₄ are closed, contacts S ₂ and S ₃ are open.

Further, as the switch SW, a switch by either mechanical or electrical means may be used,
Furthermore, the switching may be performed by either manual or automatic means.

[Brief explanation of the drawing]

The drawings show an embodiment of a traveling vehicle according to the present invention,
Figure 1 is an overall side view of the lawn mowing vehicle, Figure 2A is a diagram showing the configuration of the orientation sensor, Figure 2B is a detection signal waveform diagram, Figure 3 is a block diagram of the control system, and Figure 4 is a diagram showing the configuration of the orientation sensor. is a flowchart showing the operation of the control device. 1...Vehicle body, 5...Direction sensor, SW...Detection signal switching means, Vx, Vy...Voltage signal, Yp
……Average value.

Claims (1)

[Scope of Claim for Utility Model Registration] A running vehicle equipped with a direction sensor 5 that senses the earth's magnetism and outputs a pair of voltage signals Vx and Vy having a 90 degree phase difference in accordance with the direction, which has the following ( stomach)~
A traveling vehicle characterized by having the configuration (e). (a) A control device 11 that inputs the pair of voltage signals Vx and Vy from the orientation sensor 5 and outputs a signal for rotating the orientation sensor 5 around the vertical axis P is connected to the orientation sensor 5. It is linked with (b) The orientation sensor 5 is connected to the vertical axis P.
Angle detection device PM that detects the rotation angle around the
It is equipped with (c) The control device 11 includes forced rotation signal output means for outputting a signal for rotating the orientation sensor 5 by 360 degrees around the vertical axis P. (d) The control device 11 samples the pair of voltage signals Vx and Vy detected at every predetermined angle θp during the rotation of the orientation sensor 5 in (c) above, and performs control based on the sampling results. Then, one of the pair of voltage signals Vx, Vy is compared with the maximum and minimum average value Yp of the one voltage signal, and the one voltage signal output corresponding to the direction is the average value Yp. direction signal calculation means for obtaining a direction signal of the traveling direction by adding a positive or negative sign to the other of the pair of voltage signals Vx, Vy output corresponding to the direction. We are prepared. (E) A running vehicle characterized by comprising a switching means SW for switching which of the pair of voltage signals Vx and Vy is selected as the one and the other.