JPH0323924B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a traveling vehicle equipped with a tracing sensor, in detail,
The present invention relates to a traveling vehicle equipped with a tracing sensor, which includes a tracing sensor that detects a predetermined boundary of a running area, and a control device that controls the vehicle body to automatically travel along the detected boundary.

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

However, in the conventional example, it was possible to detect whether the vehicle body crossed the boundary in an ON/OFF manner, but it was not possible to detect the 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 move.

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 that are equipped with tracing sensors have the disadvantage that the mowing tracks become undulating and spoil the aesthetic appearance, which is a serious problem.

In addition, in the past, after the vehicle entered the boundary, the steering was operated at a constant steering speed so that the scanning sensor entered the boundary detection state, so even if the approach angle to the boundary was the same, the vehicle speed was different.
There were cases where the steering operation could not follow the vehicle speed, and as mentioned above, there was an inconvenience that the vehicle body could not be properly aligned with the boundary.

The present invention has been made in view of the above-mentioned circumstances, and when a vehicle enters the boundary between a working area and a non-working area, it is possible to perform optimal steering control corresponding to the approach angle. The purpose of the present invention is to provide a traveling vehicle with a tracing sensor capable of performing control accurately regardless of vehicle speed.

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 has the following features: [a] The copying sensors are arranged in parallel at a predetermined interval in the left and right direction at the front of the vehicle body. It consists of two sensors.

[B] A distance sensor capable of continuously detecting the moving distance of the vehicle body is provided.

[C] 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.

[d] The control device controls the distance of the vehicle body relative to the boundary based on the detected moving distance detected by the distance sensor during the boundary detection time difference between the two sensors and the predetermined interval between the two sensors. The vehicle is equipped with approach angle calculation means for calculating the approach angle based on the following equation, θ=tan ⁻¹ (d/x).

[E] The control device includes a vehicle speed calculating means for calculating a vehicle speed based on the detected moving distance and the boundary detection time difference between the two sensors.

[F] The control device includes a steering speed setting means that sets the steering speed to be higher as the calculation result of the vehicle speed is larger.

[g] 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 is that it has the configurations described in [A] to [G] above.

Because of this characteristic structure, the following excellent effects have been achieved.

In other words, with a simple structure that uses a tracing sensor, the approach angle to the boundary of the vehicle body can be detected reliably and accurately, and the steering control is performed so that the steering speed increases as the vehicle speed calculation result increases. Even with the steering amount and steering speed that correspond to the vehicle speed and vehicle speed, it is possible to perform optimal steering control so that the vehicle body follows the boundary and the sensor detects the boundary, increasing efficiency with a single steering operation. It has now been possible to align the border well.

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, 3 of the vehicle body 1 so as to be movable up and down, and an unmowed lawn area and an already mown lawn, which is the boundary between the running areas, are placed 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.

Furthermore, a fifth distance sensor 5 is installed in the vehicle body 1 and generates one pulse per unit traveling distance K to continuously detect the moving distance of the vehicle body 1.
A ring has been set up.

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

As shown in FIG. 2, the two optical sensors S ₁ and S ₂ constituting the copying sensor A are provided on the lawn mower 4 with U-shaped sensor frames 7, 7 separated by a predetermined distance d. Sensor mounting frame 8
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, and the light-emitting element S ₁ and the light-receiving element
S ₂ is configured to determine the boundary between unmown land and mowed land by sensing the presence or absence of grass introduced as the vehicle body 1 travels. Note that the sensor A is not limited to one using the optical sensors S ₁ and S ₂ , and may be constructed from any type of sensor, whether contact type or non-contact type.

FIG. 3 shows the determination of the approach angle (θ) of the vehicle body to the boundary 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 determination of the approach angle (θ) of the vehicle body to the boundary. ) is a block diagram of a control device 9 configured to steer the front wheels 2, 2 with a steering amount corresponding to .

The control device 9 includes an I/O port 10, a CPU
11, a memory 12, and a counter 13.

Then, the control device 9 determines the approach angle (θ) to the boundary based on the time difference between turning on of the optical sensors S ₁ and S ₂ forming the copying sensor A and the vehicle body movement distance x during that time, and This approach angle (θ)
An electromagnetic valve 14 installed in the hydraulic circuit of the hydraulic cylinder 6 is driven via a buffer circuit 15 in order to steer the front wheels 2, 2 in a predetermined direction with a steering amount corresponding to the steering amount.

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 causes the vehicle body 1 to align with the boundary 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 . and a tracing drive command means for commanding the steering drive mechanism, and as described later, the moving distance x detected by the distance sensor 5 during the boundary detection time difference by the optical sensors S ₁ and S ₂ , The above-mentioned mounting interval d of optical sensors S ₁ and S ₂
Accordingly, it is provided with an approach angle calculation means for calculating an approach angle (θ) with respect to the boundary of the vehicle body 1, and
A vehicle speed calculating means is provided for calculating a vehicle speed (v) based on the travel distance x and a boundary detection time difference between the optical sensors S ₁ and S ₂ , and the steering speed is set to be higher as the calculation result of the vehicle speed (v) is larger. The vehicle also includes a steering speed setting means for steering the front wheels 2 in a predetermined direction in accordance with the calculated approach angle (θ), and an approach direction control means for instructing to steer the front wheels 2 in a predetermined direction after a certain period of time has elapsed. has been done.

Hereinafter, the procedure for calculating the approach angle (θ) at the boundary between uncut land and cut land will be explained based on the conceptual diagram for detecting the approach angle (θ) shown in FIG. 4.

That is, when 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, the optical sensor _S1 first detects the unmown field, and the control device 9 receives this detection signal and Activate counter 13,
Counting of the number of output pulses from the distance sensor 5 is started. Then, as the vehicle body 1 travels, when the optical sensor S ₂ detects an unmoved ground, the counter 13 is stopped and the vehicle body 1 is calculated based on the number of pulses (n) counted during this period and the unit distance traveled (K). The distance traveled, that is, the respective sensors S ₁ and S ₂ are shown in the figure.
The moving distance x to the positions S ₁ ′ and S ₂ ′ is calculated as x=K·n.

Then, this moving distance x and both the sensors S ₁ ,
Based on the mounting interval d of _S2 , the approach angle (θ) is calculated based on the following formula ().

θ=tan ^-1 d/x ...() Then, the hydraulic cylinder 6 is driven to achieve a steering angle corresponding to this approach angle (θ), and the front wheels are steered in a predetermined direction (to the right when the approach is in the direction shown). 2, 2 is steered by a predetermined amount.

By the way, when detecting the moving distance x, the counter 13 counts the number of pulses (n) from the distance sensor 5, and also counts the elapsed time (t).
At the same time, count the vehicle speed (v) and calculate the vehicle speed (v) as v=
Based on this vehicle speed (v), the pulse and duty ratio (pw) for driving the electromagnetic valve 14 are changed to achieve a steering speed corresponding to the vehicle speed, and The hydraulic cylinder 6 is driven with a steering amount corresponding to the approach angle (θ), the steering control corresponding to the vehicle speed (v) and the approach angle (θ) is performed, and after a predetermined period of time, reverse steering is performed. It has been done.

Incidentally, FIG. 5 is a flowchart showing a routine of the above-mentioned control device 9 at the time of entry. 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.

[Brief explanation of the drawing]

The drawings show an embodiment of a running wheel with a tracing sensor according to the present invention, in which Fig. 1 is an overall plan view, Fig. 2 is a front view of main parts, Fig. 3 is a block diagram of the control device, and Fig. 4 is an approach view. A conceptual diagram of angle detection, and FIG. 5 is a flowchart showing the operation of the control device. 1... Vehicle body, 2... Front wheel, 5... Distance sensor, 9... Control device, A... Copying sensor, S ₁ ,
S ₂ ...sensor, d...predetermined interval, x...movement distance.

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 moved 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] A distance sensor 5 is provided that can continuously detect the moving distance of the vehicle body 1. [C] 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. [d] The control device 9 controls the two sensors.
Detected moving distance x detected by the distance sensor 5 during the boundary detection time difference between S ₁ and S ₂
and the predetermined interval d between the two sensors S ₁ and S ₂ , calculate the approach angle (θ) of the vehicle body 1 with respect to the boundary based on the following formula, θ=tan ^-1 (d/x). The vehicle is equipped with approach angle calculation means. [E] The control device 9 controls the detected movement distance x
and the boundary detection time difference between the two sensors S ₁ and S ₂ to calculate the vehicle speed (v). [F] The control device 9 includes a steering speed setting means that sets the steering speed to be higher as the calculation result of the vehicle speed (v) is larger. [G] 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 then instructing to switch after a certain period of time has elapsed. . A traveling vehicle with a tracing sensor characterized by having the configuration described in [A] to [G] above.