JPH0323922B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a traveling vehicle equipped with a tracing sensor, and more particularly, a tracing sensor that detects a predetermined boundary of a traveling area, and a control that controls the vehicle to automatically travel along the detected boundary. The present invention relates to a traveling vehicle with a tracing sensor, which is equipped with a device.

Conventionally, in this type of vehicle equipped with a tracking sensor, a sensor is installed on the vehicle body to detect the boundary of the driving area, and the steering wheel is automatically steered by a certain amount in a predetermined direction based on the boundary detection result of this sensor. In order to automatically travel along this boundary, tracing travel control has been performed.

However, in the conventional example, it was possible to detect whether the vehicle body crossed the boundary by turning ON or OFF.
It was not possible to detect it up to that angle of approach.

Therefore, when approaching a boundary of the vehicle body, the vehicle body is steered in the opposite direction with a constant steering amount regardless of the approach angle, and when the boundary is detected again, the vehicle body is steered in the opposite direction, and so on. The steering was controlled to make the vehicle run.

Therefore, when approaching the boundary of the vehicle body, depending on the angle, the steering wheel may be steered more than necessary and turn too much, making it impossible to properly align the vehicle body with the boundary, and steering operation in the opposite direction may be impossible. It is easy to cause the so-called hunting phenomenon, which is said to repeat permanently, and for this reason, in particular,
Lawn mowing vehicles equipped with tracing sensors have the disadvantage that the mowing marks are undulating and spoil the aesthetic appearance, which is a serious problem.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to adjust the approach angle to the boundary in order to perform optimal steering control corresponding to the approach angle when the vehicle approaches the boundary of the driving area. An object of the present invention is to provide a traveling vehicle equipped with a tracing sensor capable of detecting the following.

In order to achieve the above object, a traveling vehicle with a copying sensor according to the present invention has the above-mentioned structure, and includes: (a) two copying sensors arranged side by side at a predetermined interval in the left and right direction at the front of the vehicle body; It is composed of sensors.

[b] The control device issues a following driving command to the steering drive mechanism to align the vehicle body along the boundary based on the detection results of the boundary between the working area and the non-working area by the two sensors. have the means.

[c] The control device includes vehicle speed information of the vehicle body;
A moving distance calculating means is provided for calculating a moving distance of the vehicle body from a time difference between when one of the two sensors detects the boundary and when the other sensor detects the boundary.

[d] The control device determines the approach angle of the vehicle body with respect to the boundary based on the calculated travel distance and the predetermined interval between the two sensors.
An approach angle calculating means is provided for calculating based on the following equation θ=tan ⁻¹ (d/x).

[E] The control device steers the front wheels in a predetermined direction in accordance with the calculated approach angle,
It is provided with approach direction control means that instructs switching after a predetermined period of time has elapsed.

The characteristic configuration includes the configurations described in [A] to [E] above.

The effects of this characteristic configuration are as follows.

In other words, the approach angle to the boundary of the vehicle body is calculated based on the installation interval between the two sensors that are originally provided as a copying sensor and are installed side by side along the left and right direction, the time difference between boundary detection between these sensors, and the vehicle speed. Since a control device is installed to shift to the following driving state using steering control corresponding to the calculated approach angle, the sensor has an extremely simple configuration, but it can easily determine the approach angle to the boundary of the vehicle body. In addition, the front wheels can be controlled with a steering amount that corresponds to the approach angle to the boundary of the vehicle body, so it is possible to align the front wheels well with the boundary with a single steering operation in accordance with the approach angle. Therefore, it has now become possible to perform automatic tracing travel extremely efficiently and stably.

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

As shown in FIG. 1, a lawn mowing device 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 an unmown lawn that is the boundary between the running area and an already mown lawn are located in front of the vehicle body 1. Tracing sensors A, A, which will be described later, are provided on the front left and right sides of the vehicle body 1, respectively, for determining the boundary with the mowed field, thereby constructing a lawn mowing vehicle as a traveling vehicle with tracing sensors.

The front wheels 2, 2 are configured as steering wheels to be steered in the left-right direction by a hydraulic cylinder 6 based on the boundary detection result of the copying sensor A.

an optical sensor S ₁ constituting the scanning sensor A;
As shown in FIG. 2, S ₂ has U-shaped sensor frames 7 fixed to a sensor intermediary frame 8 provided on the lawn mower 4 with a predetermined distance d between them. A light emitting element P ₁ and a light receiving element P ₂ are provided as a pair on the inner facing surfaces of the sensor frame 7, respectively, and the light emitting element P ₁ and the light receiving element P ₂
By sensing the presence or absence of grass that is introduced as the vehicle body 1 travels between the two, the boundary between unmowed land and mowed land is determined. Note that the sensors S ₁ and S ₂ are not limited to optical sensors, and may be of any type, whether contact or non-contact.

FIG. 3 shows how the approach angle θ to the boundary is determined based on the detection result of the boundary between the unmown field and the mowed field by the scanning sensor A configured as described above, and the steering wheel corresponding to the approach angle θ is shown in FIG. 2 shows a block diagram of a control device 9 configured to steer the front wheels 2, 2 in a controlled manner.

That is, the control device 9 has the I/O ports 10,
It is composed of a CPU 11, a memory 12, and a counter 13. Then, the control device 9
Optical sensors S ₁ and S ₂ forming the scanning sensor A
ON time difference (t) and sensor installation interval d
Based on this, the approach angle θ of the vehicle body to the boundary is determined, and the hydraulic cylinder 6 is operated to steer the front wheels 2, 2 in a predetermined direction with a steering amount corresponding to this approach angle θ (for example, in a proportional relationship). It is driven via a buffer circuit of an electromagnetic valve 14 interposed in the hydraulic circuit.

In addition, 16 is a hydraulic pump, and this hydraulic pump 16, the front wheel 2, the hydraulic cylinder 6, and the electromagnetic valve 1
4 and the buffer circuit 15 constitute a steering drive mechanism. Therefore, the control device 9, based on the detection result of the boundary between the uncut land as a working area and the mowed land as a non-working area by the optical sensors S ₁ and S ₂ ,
It is equipped with a copying operation command means for instructing the steering drive mechanism to align the vehicle body 1 along the boundary, and as described later, the working speed v information of the vehicle body as the vehicle speed and the optical sensor S ₁ are connected to the boundary. A moving distance calculation means is provided for calculating the moving distance x of the vehicle body 1 from the time difference until the halo sensor S ₂ detects the boundary, and the calculated moving distance x
and the distance d between the optical sensors S ₁ and S ₂ to calculate an approach angle θ with respect to the boundary of the vehicle body. The vehicle is configured to include approach direction control means for instructing to steer the vehicle and then to switch after a certain period of time has elapsed.

Next, a procedure for determining the approach angle θ to the boundary will be explained based on a conceptual diagram of detecting the approach angle θ shown in FIG.

If the vehicle body 1 enters the border from a mowed field toward an unmown field diagonally in the direction of the arrow shown in the figure for some reason,
Since the optical sensor S ₁ first detects the unmowed ground, the control device 9 receives this detection signal and activates the counter 13 to start counting the elapsed time. Thereafter, when the optical sensor S ₂ detects an unmoved area as the vehicle body 1 travels, the counter 13 is stopped and the distance traveled by the vehicle body 1 is calculated based on the count value (t) counted during this period and the working speed v. , the moving distance x of the sensors S ₁ and S ₂ to the positions S' ₁ and S' ₂ shown in the figure, respectively, is calculated as x=vt. In this case, the speed v is set as a predetermined constant working speed. Then, based on the moving distance x and the mounting interval d between both the sensors S ₁ and S ₂ , the approach angle θ is calculated based on the following equation ().

θ=tan ^-1 d/x ... () Then, corresponding to this approach angle θ, for example, a steering amount f(θ) is determined based on a proportional relationship, and the hydraulic cylinder 6 is driven to achieve that steering angle. The front wheels 2, 2 are steered in a predetermined direction (to the right when the vehicle enters in the direction shown in the figure), and then reversely steered after a certain period of time has elapsed.

Incidentally, FIG. 5 is a flowchart showing a routine when the above-mentioned control device 10 enters the vehicle. As shown in the figure, when this approach routine is completed, the routine moves to a normal copying control routine (SUB).

In addition, in the flowchart of Figure 5,
WAIT means that the steering control is placed in a standby state until a reverse steering operation is started after the steering has been performed by a predetermined amount.

In addition, in the above approach routine, which side of the left and right scanning sensors A is used depends on which side of the vehicle body the uncut land is located on. , the selection and switching of both sensors A and A may be performed manually,
Alternatively, the detection may be performed automatically by separately providing a sensor for detecting the position of the unmowed land.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings illustrate an embodiment of a traveling vehicle with a tracing sensor according to the present invention, and FIG. 1 is an overall plan view, and FIG.
3 is a block diagram of the control device, FIG. 4 is a conceptual diagram of approach angle detection, and FIG. 5 is a flowchart showing the operation of the control device. 1...Vehicle body, 2...Front wheel, 9...Control device, A
...Copying sensor, S ₁ , S ₂ ...Sensor, d...
Sensor installation interval, θ... Approach angle.

Claims (1)

[Claims] 1. Tracing sensor A that detects a predetermined boundary of a running area
and a control device 9 that controls the vehicle body 1 to automatically travel along the detected boundary, [a] The vehicle body 1 is configured to move the contour sensor A to the left and right in front of the vehicle body 1. It is composed of two sensors S ₁ and S ₂ arranged in parallel at a predetermined distance d in the direction. [B] The control device 9 controls the two sensors.
Based on the detection results of the boundary between the working area and the non-working area by S ₁ and S ₂ , a following driving command means is provided which instructs the steering drive mechanism to align the vehicle body 1 along the boundary. [C] The control device 9 uses the vehicle speed v information of the vehicle body 1 and the time difference between when one of the two sensors S ₁ and S ₂ detects the boundary until the other detects the boundary, A moving distance calculation means for calculating the moving distance x of the vehicle body 1 is provided. [d] The control device 9 calculates the approach angle θ of the vehicle body 1 with respect to the boundary using the calculated travel distance x and the predetermined interval d between the two sensors S ₁ and S ₂ using the following formula θ = tan ^-1 (d/x). [E] The control device 9 includes approach direction control means for steering the front wheels 2 in a predetermined direction in accordance with the calculated approach angle θ, and instructing the steering to be switched after a certain period of time has passed. A traveling vehicle with a tracing sensor, characterized by having the configuration described in [A] to [E] above.