JPH01231808A - Device for guiding mobile working car - Google Patents

Abstract

PURPOSE:To advance a mobile working car in a direction vertical to a base line while correctly detecting a moving direction of the mobile working car by setting a pair of base points measuring distance at arbitrary two positions putting a working division between therewith and installing plural ultrasonic receivers in the mobile working car. CONSTITUTION:A mobile working car 2 moving in a direction vertical to a base line (I) connecting a pair of base points measuring distance is installed plural ultrasonic receivers 5, 5,.... In case of installing the receivers 5, 5,... on the longitudinal center line passing through the center of the breadth of the working car 2, the car is preferably guided as two distances of front and back receivers apart from the base point 3 in a direction along the base line (I) are equal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a guidance device for a mobile working vehicle, and can be used for mobile agricultural machinery such as a tractor working machine, a lawn mower, and the like.

Conventional technology and problems to be solved by the invention Conventionally, it has been common for vehicles, aircraft, etc. to use radio waves to detect the distance and direction to a target and be guided. Measuring instruments are expensive. It is also common to use ultrasonic waves to measure short distances.

However, for example, if a mobile agricultural machine is
When guided straight ahead while measuring the distance to two targets whose positions are known and detecting their direction of movement, the planned straight course can generally be set, and the distance to the target can be determined using ultrasound. The vehicle is then measured and controlled in a straight line along the planned course.

Main tasks in farming can be done with inexpensive equipment.

In this case, although it is easy to detect the position using an ultrasonic sensor, there is a problem in that it is difficult to detect the direction in which the installed working machine itself is facing.

Means for Solving the Problems This invention provides a pair of distance measurement reference points located at two arbitrary positions sandwiching the working section fil (11) near the periphery of the working section fil of the mobile work vehicle (2); Ultrasonic waves are transmitted and received between the mobile work vehicle (2) and the mobile work vehicle (2), which is moved in a direction perpendicular to the reference line (A) connecting the measurement reference points (3) and (4). In a guidance device that guides while detecting the movement position by measuring the distance between (2) and each of the base points (3) and (4),
A guiding device for a mobile working vehicle is characterized in that the mobile working vehicle (2) is provided with a plurality of ultrasonic receiving devices (5).

Functions and Effects of the Invention Since the mobile work vehicle (2) is provided with an ultrasonic receiving device (6), ultrasonic transmitting devices are provided at the distance measurement base points (3) and (4) so that the ultrasonic wave can be received by the receiving device. A mobile work vehicle (
In the case where the plurality of ultrasonic receiving devices (6) provided in 2) are arranged at two positions, for example, at the front end and the rear end on the longitudinal center line passing through the center of the width of the mobile work vehicle (2).

These front and rear receiving devices (6) and (6) can measure the distance to the measurement reference point (3) on either the left or right side of the traveling direction.

Therefore, the distance between measurement reference points (3) and (4) on the reference line (a), which can be measured and known in advance, is shared as the base, and the apex of the front receiving device (6) and By calculations on the two triangles, the triangle whose apex is the rear receiving device e(6), the front and rear receiving devices (6) and (6) determine the measurement reference point on the − side ( 3)
If the horizontal distances along the reference line (a) are equal, the direction in which the mobile work vehicle (2) is facing will be the same as the reference line (a).
This proves that the steering wheel is pointing in a direction perpendicular to (b), and if it is not equal, it is deflected to the right or left, so it can be corrected by outputting a steering operation based on the result. In addition, if the planned course is set at a distance laterally from the measurement reference point (3) on the negative side, check whether the moving vehicle body (2) matches the planned course or not. It can simultaneously detect the direction you are facing and guide you along a planned course.

Furthermore, for example, if the ultrasonic receiving devices (6) and (6) are provided in a pair of left and right units equidistantly in the left and right direction orthogonal to the center line of the moving vehicle body (2), the measurement base point (3) and(
From calculations on two triangles whose base is between 4) and whose vertices are 6 and 6, we can find the distance from these 6 and 6 to the reference line (A). If these distances are equal, it can be detected that the direction of the mobile work vehicle (2) is correct. In addition, as a combination of these, even if four ultrasonic receivers are installed on the front, rear, left, and right sides, the moving vehicle body (2
) direction can be detected.

In this way, by providing a plurality of ultrasonic receiving devices (6) as distance sensors, it is possible to solve the drawback of ultrasonic distance sensors, which is that it is difficult to determine the exact direction, at a low cost.

Embodiment In addition, the work section (1) in the rotation is an example of a rectangular work section (1), and the mobile work vehicle (2
) is shown as an example of a case where the vehicle moves straight back and forth. This work vehicle (2)
A pair of distance measurement reference points (2) and (3) are located near the midpoint of the longitudinal distance (L) of the ridge (7) on the left and right sides in the straight direction.
), and set the reference line (a) connecting these base points (2) and (3) along the short side of section (1) and along the work vehicle (2).
It is installed perpendicular to the direction of travel. This measurement base point (3
) and (4) by measuring the distance (W) in advance to find the known distance (
W).

The mobile work vehicle (2) is a tillage work vehicle (2) equipped with a rotary tillage device (9) at the rear of a tractor having a cabin (8), and the tractor has a pair of left and right front wheels that can be freely steered. Wheels (10) and a pair of left and right driven rear wheels (11)
It is a general tractor that has a bonnet [15] in which the engine is housed in the front part, and a control device including a control handle (1) and a driver's seat inside the cabin.

The upper surface of the cabin (8) is used as an attachment part for an ultrasonic receiver W (5). In addition, the steering mechanism (141) connected to the steering wheel (13) has a shaft that can measure the steering angle (
A steering angle sensor (Is) is provided at 19, and a hydraulic cylinder (11) is installed between the vehicle body (171) and the steering mechanism (141, and this hydraulic cylinder (Is3) is extended or linearly moved by the control output. Front wheels (10
1 steering operation is possible.

The measurement reference points (3) and (4) are the support Q on the ridge (7) mentioned above.
3 is erected, and an ultrasonic transmitter (6) is installed on top of the ultrasonic transmitter (6) that transmits ultrasonic waves in a direction that can also be received by mobile work vehicles (2) located at all positions within the work zone ill. The transmitting device (6) is provided so as to be able to transmit using a power source such as a power line or a battery that is separate from the mobile work vehicle (2). This base point (
The ultrasonic transmitting devices (6) and (6) in (3) and (4) emit pulses with the same period, but the transmitting device (6) at one base point (3) is different from the transmitting device (6) at the other base point (4). ) is caused to transmit with a slight delay. For example, when transmitting at intervals of - seconds, if measurement base point (4) is delayed by 1/3 second from measurement base point (3), the next 2/3
The measurement reference point (3) will transmit after a second, so it will be 1/3 second and 2/2 second.
This configuration allows the receiving device (5) to distinguish and recognize transmission from the measurement base point (3) and transmission from the measurement base point (4) by alternately generating pulse intervals of 3 seconds. In addition, in order to make the start of measurement of the time required for ultrasonic wave arrival on the receiving device (5) side to coincide with the transmission timing of the transmitting device (6), each emitting device (71 device (61 (6+) and receiving device (61 (6+) This configuration allows the receiving device (5) to reserve the transmission timing of one transmitting device (6) by synchronizing each timer counter with the receiving device (5).

This synchronization means, for example, includes providing another transmitting command radio wave transmitter and providing a command radio wave receiver for each ultrasonic transmitter (6) and the ultrasonic receiver (5), so that each pulse of the command radio wave is received. The transmitting devices (6) and (6) may be configured to transmit signals with a time difference, and the receiving device (5) may be configured to restart the ultrasonic wave arrival time for a total of 41 times.

The ultrasonic receiving device (5) uses a receiver (5A) and a computer (CPU) as main components to detect pulses of ultrasonic waves received by the receiver (5A), input them directly to the computer (CPU), and latch ( ), measure the required time with a timer counter, input it to (cpu), and
), the calculation control section (5B) is configured to perform distance calculation, position calculation, detect the orientation of the work vehicle (2), and output a steering operation to the work vehicle (2) based on the results.

This ultrasonic transmitter (5) is placed in the cabin (8) on the center line in the longitudinal direction passing through the center of the width of 1-
) They are arranged in pairs on the top surface. In FIG. 6, ((d) is the solenoid valve that operates the hydraulic cylinder (Ilm), (P) is the hydraulic pump, and (T) is the oil tank.

The function of detecting the position of the mobile work vehicle (2) and the direction of the work vehicle (2) in the rectangular work area will be explained with reference to FIG. The position of the measurement reference point (3) is (A), the position of the reference point (4) is (B), the position of the front ultrasonic receiver (5) is (PI), the position of the rear receiver (5) is (P
2), the intersection position of the planned course (b) in the direction of travel passing through these (PI) (P2) and the reference line (a) is (p
o), and the distance between points (A) and (B) is (W), (Pl
) to the reference line (A) is (y), the distance between (PI) (P2) of the front and rear receiving devices (6) is (12),
Letting (X) be the distance from the position (A) to the planned course (B), (W) and (U) are measured in advance and stored in the (CPU) as known distances. Also.

(x) divides (W) by the working width (c) of the mobile work vehicle (2), and uses the center line of that width (c) as the planned course (b), and reciprocates from the right side of the work area (1). The (X) indicating the position of each planned course (b) in which the work is to be carried out sequentially to the left is stored in (c p u) as a known value in advance such as (Xl-K2, K3-=Xi). In this way, the distance measured at each moving position is (P,) (A)
Distance between (a), (PL) (B) Distance between (b)
, (P2) (A) distance between (C), (P2) (B)
The distance (d) between Therefore, triangle (Pi) (
A) (PO) and triangle (PL) (B) (
PO), it is expressed as a2-b2=2wx-K2. As mentioned above, (w) and (X) are known numbers, so 2w on the right side
If you calculate in advance as x-x”=kl (constant),
? 1 ill Using the distance between (a) and (b), when it is to the right of the planned course (b),...a2-b2
-Kl>O (plus) When located on the planned course (b)...a"-b"
-1;0 When it is to the left of the planned course (b)...a ” -
(a) (b) measured for each ultrasonic pulse and the constant (K1
) can be used to detect the position of the mobile work vehicle (2) to the left or right of the planned course (b).

In addition, to detect the traveling direction (orientation) of the mobile work vehicle (2), from the triangle (PL) (A) (Po) and the triangle (P2) (A) (PO), c''
-a2=2Ly+L2.

(y) is calculated using this formula using the known distance (x) and the measured distance (a), and the 2 on the right side is
Calculate Ly+L"= as 2 (constant). Towards the right from the planned course (b)... C2a 2< K 2 Direction along the planned course (b)... Q" -a 2= K.

Looking to the left from the planned course (b)... C”-a2)K.

By using the constant values (c) and (a) and comparing them with (k2), the longitudinal direction of the mobile work vehicle (2) can also be checked.

Next, from the transmission of each ultrasonic transmitter (6) to the receiver (
The arithmetic control action by reception of 5) will be explained with reference to FIG. 311 Ultrasonic pulses with a minute time difference from each ultrasonic transmitter (6) at fixed base points (3) and (4) are transmitted to the ultrasonic receiver (5) at the front position (Pl) and the ultrasonic receiver (5) at the rear position (Pl). ) is received by the receiving device (5) of the computer (cpU
) measures the distance from base points (3) and (4), and positions the work vehicle relative to the planned course (b) as described above.

and the direction (orientation) of the vehicle in front of the mobile work vehicle (2) @
(1ω) determines whether or not steering operation is necessary, and when it is determined that it is necessary, outputs to the solenoid valve (19) until the steering angle reaches the steering angle determined by the steering angle sensor (161) depending on the amount of position and direction correction, and outputs to the hydraulic cylinder (IIIJ). The work vehicle (
2) to correct the position and direction of the vehicle so that it follows the planned course (b).

In this way, the longitudinal direction of the mobile work vehicle (2), which cannot be detected by the ultrasonic receiving device (5), can be detected.

Detection is performed by a minimum of two receiving devices f51f51, and there is an effect that control can be performed to quickly follow the planned course by reducing zigzag marching.

In addition, what is shown in FIG. 7 and FIG. 8 is another embodiment regarding the arrangement of the ultrasonic receiving device (5) in the mobile work vehicle (2), and the receiving device (5) is paired as a pair to perform the work. It is installed at a distance (B) from the longitudinal center line (D) of the car (2) to the right and left sides, and is installed on the top of the cabin (8) in the example shown in Figure 1, but it may also be installed on the bonnet (121). According to this, as shown in the action diagram in Figure 8, it can be used on either the left or the right, but
The receiving device (5) on the left side is guided along the planned course (b), and the headland 112G is placed at the start and end of the work progress direction (d), and the tilling start and end of the rotary tilling device (9). A headland (E) is set at , and the distance (y) from the position (Pl) of the receiving device (5) to the reference line (A) at this position can be measured. Also, the position of the base point (3) (A
) to the scheduled course (b) is also set and known. Also, the position of the receiving device (5) on the right side (P
l) and the reference line (from Pl) along the traveling direction (d).
The intersection position of the vertical line drawn on A) and the reference line (A) is
3), the position (B) of the base point (4) is a triangle (Pl
) (A) (PO) , and triangle (Pl) (B
) (P3) to c, ”-a2= 2 B x +
If B is obtained and the right-hand side is calculated from the known numbers of (B) and (X) to be a constant (K3), then to make the front and rear direction of the work vehicle (2) perpendicular to the base $ line (A) c 2- a 2k -> 0 ... facing to the right (corrected to the left) C2-a 2- k 3 = 0 ... facing correctly C 2- a '' k , < 0 ...・The direction of correction to the right or left can be detected and output based on whether the calculation result of this expression is (+) or (-), such as ``It is facing left (corrected to the right)''.

In addition, if the measurement results of the distance (d) between the base point (4) position (B) and the receiving device (5) at the position (Pl) are used, movement will occur regardless of the distances (x) and (y). The longitudinal direction of the work vehicle (2) can be detected. That is, (c2-a”)
+ (b”-d2) -28W>0...facing to the right.

(c2-a2)+ (b"-d")-2BW=0...
facing correctly.

(c2-a2)+(b2-d") 2BW<0...
facing left.

In this way, the position and direction of the working vehicle (2) can be detected even if the receiving devices (5) are provided as a pair on the left and right sides.

Furthermore, what is shown in FIGS. 9 and 10 is another embodiment, and as a modification of the first embodiment, the mobile work vehicle (2) is provided with a distance (L) in the front and back and a distance (B) in the left and right directions. , four ultrasonic receivers (5) are arranged on the front, rear, left and right sides. is set up so that it can receive the ultrasonic wave from the base point (3) on the left side, and the front and rear receiving devices on the left or right +5
++51 to follow the planned course (b), and in a configuration where the mobile work vehicle (2) has a cabin (8), the fender C! It is desirable to provide it on the ll. In addition, in this case, since the distance (L) between the front and rear receiving devices can be set large, for example, when measuring the distance to the base point (3), the front receiving device (
5) and the distance (c) from the rear receiving device (5) becomes larger, and the difference in signal arrival time becomes larger, so the direction measurement accuracy can be improved.

Regarding the calculation formula, as shown in Fig. 10, when the left front and rear receivers [+51 +5] are placed along the planned course (b).

It is sufficient to replace (w) in the first embodiment with (w-B).

Furthermore, what is shown in FIG. 11 is an embodiment in which the work section (1) is an irregularly shaped work section (23). (41 is set up and the two measurement base points +3)
Equipped with an ultrasonic transmitter/receiver device +51 +61 that can measure the distance from +41 to the mobile work vehicle (2), it first teaches topographical data (by manually driving around the perimeter,
or input from a data input device) to enable control of unmanned operation. As illustrated in FIG.
) are each equipped with an ultrasonic transmitter (6), and these (3
) and (・1) are defined as the reference line (a). Then, set the base point (3) position as the origin, set the reference line (a) as the X-axis, and set the coordinates of the y-axis that passes through the base point (3) and is perpendicular to the X-axis,
Divide the shaft into the working width (c) of the mobile work vehicle (2). The center line of each working width (c) is the planned course (b), and the peripheral line (
x2, x3. X4. X...
After going around each point position of these X1 to Xi, the (+) (-) values of the xy coordinates are stored in the CPU and the work is started.

This stored topographical data can be stored and reproduced, and if a topographical map is available, it is also possible to input the data on a desk.

The effect of this embodiment is that the control operation can be performed in the same pattern as the first embodiment except that the input by data teaching is required for each work section (+?3) as the first operation. When determining the position of A and B),
It is desirable that x) falls between (3) and (4). Also, the turning position of the mobile work vehicle (2) is from
It is sufficient to subtract the Y coordinate value of the Xi point by the width of the headland 30.

The effects of this embodiment are that by measuring the distance from the mobile work vehicle (2) to the measurement base points (3) and (4) using ultrasonic waves, it has good adaptability to waves on large irregularities on the ground surface, and optical guidance. It is superior in terms of form. In addition, it is most suitable for mowing lawns, and can also be used for cleaning irregularly shaped areas, cleaning beaches, and cleaning steep slopes such as ski resorts where the mobile work vehicle (2) can pitch. It can also be used for work.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is an overall perspective view, Fig. 2 is a plan view showing its operation, Fig. 3 is a partial side view, and Fig. 4 is a plan view thereof. , Fig. 5 is an enlarged 5ll-sectional view of a part of it, Fig. 6 is a control block diagram, and Fig. 7 is a control block diagram.
The drawings are a partial plan view showing the operation of another embodiment; FIG. 8 is a plan view thereof; FIG. 9 is a plan view showing the operation of another embodiment; FIG. 11 is a plan view showing the operation of yet another embodiment. In the figure, the code (1, 1 is a work section, (2) is a mobile work vehicle,
-(3) +41 is the measurement reference point, (5) is the ultrasonic receiver,
+6) indicates an ultrasonic transmitter 6

Claims (1)

[Claims] A pair of distance measurement reference points (3) and (4) placed at two arbitrary positions sandwiching the work section (1) near the periphery of the work section (1) of the mobile work vehicle (2), and each of these measurement reference points (3). )
Ultrasonic waves are transmitted and received between the mobile work vehicle (2) and the mobile work vehicle (2), which is moved in a direction perpendicular to the reference line (A) connecting (3) and (4
), which guides the mobile work vehicle while detecting its moving position by measuring the distance from the mobile work vehicle (
2), a guidance device for a mobile work vehicle, characterized in that a plurality of ultrasonic receiving devices (5) are provided.