JPH0748164B2 - Method and device for automatically raising and lowering a sensor in an automatic vehicle steering system - Google Patents

Description

The present invention relates to a method and apparatus for automatically raising and lowering a sensor in an automatic steering apparatus for a vehicle such as a snowplow.

[Prior Art] A magnetic marker (ferrite marker) of ferromagnetic material is laid on the road surface, a magnetic field is emitted from an exciting coil of a sensor provided on a vehicle, and a magnetic field distribution formed by the magnetic marker is detected in the sensor. The position of the magnetic sensor, that is, the relative position of the vehicle with respect to the magnetic marker is detected by the coil, and the automatic steering device of the vehicle that controls the steering device by the signal is put to practical use as a golf cart or the like. ing. As the sensitivity of this magnetic sensor, the maximum distance from the magnetic marker is about several cm at present.
Therefore, it is practically necessary to install this sensor so as to project to the lower part of the vehicle, and if the road surface is flat, there is no risk of contact with obstacles or sensitivity change due to height fluctuation of the sensor. When the height of the wheel changes with respect to the position of the magnetic marker, such as when the wheel enters a groove, the output of the sensor fluctuates or the sensor comes into contact with the road surface and is damaged. It was Therefore, conventionally, it has been used only in places where such a phenomenon is unlikely to occur (such as golf carts and FA automated guided vehicles).

[Problems to be Solved by the Invention] The technical problem of the present invention is to eliminate the above-mentioned conventional drawbacks, to enable the sensor to be held at a constant height from a road surface marked with a marker by simple control, and A method and apparatus for automatically raising and lowering a sensor that can prevent the sensitivity of the sensor from changing even when the height of the wheel changes with respect to the position of the laid marker and prevent the sensor from coming into contact with the road surface and being damaged. To provide.

[Means for Solving the Problems] A method of the present invention for solving the above problems detects a position of a marker laid on a road surface by a pair of left and right detection units of a sensor provided in a vehicle, and operates by an output signal thereof. In the vehicle automatic steering device for steering control in which the vehicle is caused to travel along the marker by the controller, the controller outputs the output signals of the pair of detection units of the sensor so that the sum of the output signals is always a predetermined value. The sensor height is automatically controlled by applying a signal for moving the sensor up and down to the drive source of the lifting mechanism.

Further, the device of the present invention is the above-mentioned vehicle automatic steering device, in which the sensor is held so as to be movable up and down by an elevating mechanism so that the sum of the output signals of the pair of detection parts of the sensor is always a predetermined value. Is provided to the drive source of the elevating mechanism to automatically control the sensor height.

[Operation] In the above-mentioned vehicle, the distance between the sensor and the marker fluctuates depending on the condition of the road surface during running. However, the controller calculates the sum of the output signals of the pair of detection coils, which is the set value at all times. As described above, the controller gives a signal for moving the sensor up and down to the drive source of the elevating mechanism, so that the sensor height is automatically controlled to the set value.

Therefore, if a vehicle equipped with a sensor enters a groove on the road surface,
Even if the height of the sensor fluctuates temporarily due to riding on a stone, the distance between the sensor and the marker is immediately returned to the state before the change, and the sensitivity of the sensor to detect the marker is kept constant. . Further, since the height of the sensor is instantaneously controlled, the sensor is not brought into contact with the road surface and is not likely to be damaged.

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

The vehicle 1 shown in FIG. 1 includes a magnetic sensor 4 for detecting a magnetic marker 3 laid on a road surface 2, and the magnetic sensor 4.
The output signals of the lifting and lowering mechanism 5 such as a hydraulic cylinder for holding and holding up and down, the driving source 6 such as a drive motor for driving the lifting and lowering mechanism 5 such as the hydraulic cylinder, and the magnetic sensor 4 are monitored, A controller 7 for sending a control signal to the drive source 6 while comparing with a reference signal is mounted.

The vehicle 1 includes an automatic steering device, and when the position of the marker 3 on the road surface 2 is detected by a pair of left and right detection units of the sensor 4 which will be described later, a controller 7 that operates according to an output signal of the detection unit is used. The steering control is performed by the automatic steering device so that the vehicle 1 travels along the marker 3.

As shown in FIG. 2, the magnetic sensor 4 includes an exciting coil 11 for generating an alternating magnetic field to form a magnetic field by a magnetic marker (ferrite marker) 3 laid on the road surface 2, and a magnetic field distribution by the magnetic marker 3. The detection coils 12 and 13 forming a pair of left and right detection units for detecting the variation of When the position of the sensor 4 is shifted from the magnetic marker 3 to the left or right, the detection output signal characteristic as shown in FIG. 3 is obtained. The detection output signal of the left (right) side detection coil shows a large value like A (B) when the height of the sensor 4 is low, but when the height is high, such as A '(B'). Indicates a small value. Further, the sum of the detection output signals of the left and right detection coils shows a substantially flat characteristic in the vicinity of the magnetic marker as shown in C (C ') of FIG.

Therefore, in the vehicle 1, the two detection coils are
The controller 7 obtains the sum Vs of the output signals of 12 and 13, and makes the vehicle travel while comparing it with the reference value Vr when traveling on a flat road surface.
When Vs> Vr is changed during traveling, a signal for operating the elevating mechanism 5 to raise the height of the sensor 4 is given to the drive source 6, and the interval between the magnetic markers 3 of the magnetic sensor 4 is changed. Control to return to the state of. That is, if the sensor height is increased, the sum Vs of the detection coil output signals becomes smaller and eventually approaches the reference value Vr. On the contrary, when Vs <Vr is changed during traveling, a signal for operating the elevating mechanism 5 to lower the sensor height is given to the drive source 6, and the interval between the sensor 4 and the marker 3 is changed before the change. The sensor height is lowered so that the state returns. As a result, the magnetic field strength detected by the sensor 4 becomes strong, and the sum Vr of the detection coil output signals becomes large, and eventually approaches the reference value Vr.

As described above, by monitoring the sum Vr of the detection coil output signals and feeding it back to the drive source 6 of the hydraulic cylinder, even if a sharp sensor height change occurs, the height can be instantly returned to the original height. Therefore, the magnetic sensor 4 is always held at a constant height.

Therefore, even if the wheel enters a groove on the road surface or rides on a stone, the distance between the magnetic sensor 4 and the magnetic marker 3 is controlled so as not to change at all times, and the magnetic sensor 4 does not collide with the road surface 2. Absent. That is, there is no fear that the characteristics of the sensor will change or be damaged due to the impact. Further, in this case, the sensitivity of the sensor is also kept constant.

FIG. 4 shows a situation where the wheels 8 of the vehicle 1 have entered the groove 9. Even in such a case, the distance between the magnetic marker 3 and the sensor 4 is maintained at a predetermined value, and the sensor is not damaged.

In the above embodiment, an example using a ferrite marker as a magnetic marker was described, but a permanent magnet, Al, N
An optical reflection tape such as i, Cr or the like, or a guide line having a current applied thereto can be used as a marker. When these markers are used, the corresponding sensors are mounted on the vehicle.

[Effect of the Invention] As described in detail above, according to the present invention, by controlling the height of the sensor to be kept constant, the sensitivity of the sensor to the height is kept constant. The processing circuit can be easily designed. That is, the height correction circuit of the magnetic sensor becomes unnecessary. Further, since the sensor can be prevented from being damaged, a reliable automatic guide system for the vehicle can be realized, and the vehicle can be stably fed out for work such as snow removal.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a basic configuration of an embodiment of an automatic sensor raising / lowering device according to the present invention, FIG. 2 is a partial configuration diagram showing a relationship between a sensor and a marker, and FIG. 3 is a detection coil output and a sensor position. 4 is an explanatory diagram showing a situation in which the wheel has entered a groove on the road surface. 1 ... Vehicle, 2 ... Road surface, 3 ... Marker, 4 ... Sensor, 5 ... Lifting mechanism, 6 ... Drive source, 7 ... Controller, 12, 13 ... Detection coil (detection unit), A, A ', B, B' ... Detection coil output signal, C, C '... Left and right detection coil output signal sum.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroo Wakami 4-1-1 Miyazaki, Miyamae-ku, Kawasaki-shi, Kanagawa NEC Corporation (72) Mutsoo Sakaguchi 2--11, Tamagawa, Ota-ku, Tokyo Japan Road Co., Ltd. (72) Inventor Nobumi Umeda 2-580 Horokai Kita Ichijo, Iwamizawa City, Hokkaido Masakazu Kato, Examiner, Development Engineering & Construction Co., Ltd. (56) Kai 63-9605 (JP, U)

Claims (2)

[Claims] 1. A steering control so that a vehicle runs along a marker by a controller operated by detecting a position of a marker laid on a road surface by a pair of left and right detection units of a sensor provided in the vehicle and an output signal of the detected marker. In the automatic steering apparatus for a vehicle, the controller supplies a signal for moving the sensor up and down to the drive source of the lifting mechanism so that the sum of the output signals of the pair of detection units in the sensor is always a predetermined value. ,
A method for automatically raising and lowering a sensor in a vehicle automatic steering device, characterized in that the sensor height is automatically controlled. 2. A steering control for detecting the position of a marker laid on the road surface by a pair of left and right detectors of a sensor provided on the vehicle, and a controller operated by an output signal of the marker to drive the vehicle along the marker. In the automatic steering apparatus for a vehicle, a signal for holding the above-mentioned sensor movably up and down and vertically moving the sensor so that the sum of the output signals of a pair of detection units of the sensor is always a predetermined value is provided. A controller for automatically controlling the sensor height by outputting the sensor height to the driving source of the sensor automatic lifting device for a vehicle automatic steering device.