JP2919161B2 - Electromagnetic induction vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for reliably operating an electromagnetically guided vehicle such as an automatic traveling type sprayer (speed sprayer) in an orchard along a guidance route. It is.

[0002]

2. Description of the Related Art Conventionally, a traveling vehicle such as an automatic traveling type sprayer (speed sprayer) in an orchard or the like is disclosed in US Pat. No. 3,498,403.
As shown in FIGS. 1 (a) and 1 (b), the ground 1
Guidance cable 10 buried in groove 103 along 00
1. An alternating current is passed through 1. In this case, the AC magnetic field generated in the induction cable 101 is a magnetic field concentric with the center of the cross section of the induction cable (see FIG. 11A), and the intensity of the magnetic field decreases as the distance from the center of the cross section increases.
Then, a change in the intensity of the AC magnetic field generated from the induction cable 101 is detected by magnetic sensors La and Lb such as a pair of left and right pickup coils mounted on the front of the traveling vehicle 102 or the like. Output values (voltage values) e1, from a pair of left and right magnetic sensors La, Lb generated in accordance with the lateral displacement amount m (distance, meter) of
e2 is detected and the difference e = (| e1 | − | e2
|), The lateral displacement amount m (deviation amount) and the lateral displacement direction (determination of right or left) are obtained, and from these detection results, the traveling vehicle 102 travels along the guide cable 101. 2. Description of the Related Art Steering control is performed by changing the direction of steered wheels in a traveling vehicle.

[0003]

As pointed out in the above-mentioned U.S. Patent (see FIG. 2), the sensor axis 10 of the pickup coil which is the magnetic sensors La and Lb.
4a, 104b (the cylindrical axis of the coil winding, hereinafter referred to as the sensor main axis) is appropriately angled with respect to the ground (horizontal plane) 100.
It is proposed to improve the sensitivity of the sensor by tilting only. Further, in the US patent (see FIG. 1), when the traveling vehicle 102 is viewed in a plan view, the directions of the pair of left and right magnetic sensors are arranged in a C-shape. Unknown.

By the way, as shown in FIG. 11 (b), when the guide cable is located at the intersection of the vertical line lowered from the midpoint of the distance between the left and right magnetic sensors La and Lb and the ground, the lateral displacement amount m is 0. Then, as the lateral shift amount sequentially increases from 0, the curve indicating the difference e between the output values (voltage values) of the pair of left and right magnetic sensors La and Lb becomes a peak value (maximum value or minimum value). It changes to decrease afterwards.

[0005] Ideally, at a place where the guide cable is a straight line portion, the steering control is performed so that the center line in the traveling direction of the traveling vehicle and the guide cable substantially overlap in plan view. On the other hand, when the guide cable moves from the straight section to the turning section, or at an intermediate point of the turn, the axis of the guide cable of the turning section separates rightward or leftward with respect to the traveling direction centerline of the traveling vehicle. However, it has been difficult to predict the degree of rotation (bending) of the guide cable based on the detection results of the pair of left and right magnetic sensors.

The inventor of the present invention has found that, in plan view, the sensor main axes of the pair of left and right magnetic sensors are not orthogonal to the axis of the induction cable (and, consequently, the center line in the traveling direction of the vehicle body), but are not perpendicular to the center line in the traveling direction of the vehicle body. Or tilt the main axis of the magnetic sensor positioned inside the turn forward with respect to the center line in the traveling direction of the vehicle body, and move the sensor main axis of the magnetic sensor positioned outside the It has been discovered that, when tilted by an appropriate angle backward with respect to the line, the detection result of the pair of left and right magnetic sensors is output so that the value of the difference e is calculated to be large at the turning start portion and the turning midway. did. In other words, it has been found that it can be predicted that the gap in the traveling direction of the traveling vehicle with respect to the guide cable in the turning start portion and the turning midway portion is reduced.

The present invention utilizes the above-described phenomenon to provide steering in a so-called turning portion in which a guidance route is curved or bent in an arc shape or an L-shape in plan view, at a turning start portion or a turning midway portion. It is an object of the present invention to provide a steering control device capable of executing angle control accurately.

[0008]

In order to achieve this object, in an electromagnetic induction type traveling vehicle according to the present invention, an AC magnetic field emitted from a single induction cable disposed along a guidance path is mounted on a vehicle body. While detecting with a pair of magnetic sensors,
The steering angle in the steering apparatus detected by the steering angle detection sensor, an electromagnetic induction type traveling vehicle comprising including a steering control device for steering control along the guide route, steering system
In response to the steering angle detection signal from the control device, the left and right
Change the left and right directions of the pair of magnetic sensors
Drive means for turning left and right, and turning to the left and right
As the detected value of the angle increases, the left and right magnetic
The main axis of the air sensor in plan view is
The angle to incline forward with respect to the direction center line is large.
This is provided with a control means for performing change and adjustment so as to reduce the temperature .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment in which the present invention is applied to a system for guiding an automatic traveling type chemical sprayer (speed sprayer) will be described. A driving operation unit 2 having a handle 3 is provided on the front side of the traveling vehicle 1 of the speed sprayer. The traveling vehicle 1 is provided with a chemical liquid tank 4 having a substantially L-shape in plan view and a spraying unit 5 at the rear. ing.

The spraying section 5 is provided with a large number of spray nozzles 6 facing radially outward at appropriate intervals on the outer peripheral surface of the traveling vehicle 1 except for the lower surface, and a blower fan 7 for sending wind outward in the radial direction. The spray nozzle 6 can be spray-controlled so that the spraying operation is performed every three sections or two sections on the left and right sides and the upper surface of the traveling vehicle 1. Reference numerals 8 and 8 denote left and right front wheels, and reference numerals 9 and 9 denote left and right rear wheels. These four wheels are of a so-called four-wheel drive type in which power from an engine 10 is transmitted via a traveling speed change mechanism 11 and driven. , A power transmission mechanism 12 with a blower clutch (not shown) capable of turning on / off the power from the engine 10 by a manual operation of an operator
The fan 7 is driven to rotate through the fan.

A power pump 13 for the spray nozzle 6
Is driven by an appropriate drive source such as the power transmission mechanism 12 or the like. The steering device 14 with the handle 3 is a power steering mechanism 1 including a mechanical or hydraulic system as shown in FIG.
The power steering mechanism 15 is operated by a double-acting hydraulic cylinder 17 in a hydraulic circuit 16, and when the hydraulic cylinder 17 is extended, the rear wheels 9, 9, the connecting rod 19 and the bell crank 2 having a V-shape in plan view.
The front wheels 8 and 8 are turned to the right through 0 (the front wheels are turned to the left and the rear wheels are turned to the right when the hydraulic cylinder 17 is contracted). It is a so-called four-wheel steering type.

The hydraulic circuit 16 is shown in FIG.
Is an electromagnetic solenoid type control valve for the hydraulic cylinder 17 for automatic steering, and reference numeral 29 is a control valve for controlling an actuator 30 such as a hydraulic cylinder for operating a traveling clutch. In the case of oil feed, it is connected to a hydraulic pipe 31 branched from the upstream of the control valve 23 for manual steering.

At the time of manual steering, oil is supplied from a hydraulic motor 21 which sends an oil discharge amount via a control valve 23 in proportion to the rotation angle of the handle 3 to a double-acting hydraulic cylinder 17 attached to the steering mechanism 15. In the automatic steering control, hydraulic oil is sent from the hydraulic pump 22 to the hydraulic cylinder 17 via the electromagnetic solenoid type control valve 28. Reference numeral 25 denotes a steering angle sensor such as a potentiometer capable of detecting the steering angle of the front wheel 8. In this case, the average value of the direction angles of the left and right wheels may be obtained and detected. The front wheels and the rear wheels may be connected via separate hydraulic cylinder type power steering mechanisms so that the front wheels and the rear wheels may be individually controlled.

A pair of left and right magnetic sensors 26a and 26b is provided on the lower surface of the traveling vehicle 1 at the front thereof. Each of the magnetic sensors 26a and 26b may be a pickup coil in which a conductor is wound in a coil shape, or may be a Hall element or a Hall I.
C, a magnetoresistive element, a magnetic transistor,
The intensity of an AC magnetic field generated around the induction cable 27 can be detected by an AC current of an appropriate frequency applied to the induction cable 27 by an AC current generator (not shown). At this time, the main axis of the sensor is set in a direction in which the AC magnetic field can be detected most efficiently. Induction cable 2
Numeral 7 is laid in a groove formed along a guide path which is a work path of an orchard, or buried underground.

The magnetic sensors 26a and 26b are configured to rotate left and right by step motors 53 and 55, respectively, which are driving means described later.
Rotary encoders co over Da taken in conjunction (potentiometer)
Based on the detection values of the angle detectors 56 and 57, the directions of the sensor main shafts 58 and 59 of each of the magnetic sensors 26a and 26b (the inclination angles with respect to the center line in the traveling direction of the traveling vehicle in plan view) are controlled. .

The steering control, spray control, direction adjustment control of each magnetic sensor, and the like are executed by a control device 32 such as a microcomputer. FIG. 5 is a block diagram of the control device 32 when the above-mentioned control is executed by software of a microcomputer, and a central processing unit 33 such as a microcomputer has a readable / writable memory (RAM) 3.
4 and a read-only memory (ROM) 35 are connected.

The A / D converters 36, 36 convert the detection signals from the magnetic sensors 26a, 26b into digital signals and input them to the input portion of the interface of the central processing unit 33. And the signals of the angle detectors 56 and 57 are input. When the detection signals of the pair of magnetic sensors 26a and 26b are calculated by the central processing unit 33, the amount of deviation of the lateral displacement with respect to the guide cable 27 at the front of the vehicle body is determined, and the direction of the lateral displacement (right or left) is determined. Can be determined.

A pair of left and right magnetic sensors are provided before and after the traveling vehicle 1 to operate the front steering device based on the detection and calculation results of the front pair of magnetic sensors, while detecting and calculating results of the rear magnetic sensor. , The rear steering device may be configured to operate. Reference numeral 40 denotes a level sensor such as an electric resistance type for detecting the level (water level) of the chemical in the chemical tank 4, and reference numeral 41 denotes a flow rate detection sensor for detecting the consumption of the chemical during spraying. It is connected to the input terminal of the interface in the central processing unit 33.

The following are connected to the output terminals of the interface in the central processing unit 33. That is, a drive circuit 43 for the electromagnetic clutch of the power pump 13 that sends the chemical solution from the chemical solution tank 4 to the spray nozzle 6 and a control valve 44 that is provided in the middle of the chemical solution flow pipe and can adjust and shut off the flow rate of the solution. A drive circuit 45, and an electric drive circuit 46 for a right-hand steering electromagnetic solenoid 28R of the control valve 28 for automatic steering.
And an electric drive circuit 4 for the left steering electromagnetic solenoid 28L
7, a display lamp 48 that is turned on when the chemical solution level in the chemical solution tank 4 becomes minimum, an actuator drive circuit 49 that operates the travel brake of the traveling vehicle 1, and a travel that cuts off the power transmission of the engine. Actuator drive circuit 5 for operating a clutch (electromagnetic clutch, not shown)
0, a display lamp 51 for displaying the opened state of the spray control valve 44, a drive circuit 53 for a step motor 52 for driving the left magnetic sensor 26a to rotate left and right, and a right and left drive for driving the magnetic sensor 26b. Step motor 54
Is connected to the driving circuit 55.

Next, the turning portion 2 in which the guide cable 27 is bent or curved following the linear portion 27a in plan view.
7b, when the turning steering control of the traveling vehicle is performed, the turning steering angle β (or the steering angle instruction amount)
An embodiment will be described in which the sensor main shaft 58 of the left magnetic sensor 26a and the sensor main shaft 59 of the right magnetic sensor 26b are both changed and adjusted so as to be appropriately inclined forward by an angle θ1 with respect to the center line 60 in the traveling direction of the traveling vehicle.

FIG. 6 shows a case where the guide cable of the revolving portion 27b is curved in a plan view, and FIG. 7 shows a case where it is bent. In each of these cases, the two magnetic sensors 26a and 26b are used.
Are located at the same distance from the center line 60 in the traveling direction, if the intersection E1 between the line segment AB and the center line 60 in the traveling direction is determined in plan view projection, the length AE of the line segment
1 = BE1.

On the other hand, an intersection E between the line segment AB and the turning portion 27b
2, if the sensor main axes of the left and right magnetic sensors are orthogonal to the center line 60 in the traveling direction as in the related art, the turning portion 2 is viewed in a plan view (in a plan view).
Left and right magnetic sensors 26a for the 7b induction cable,
The lateral shift amount of 26b is the length E1E2 of the line segment. On the other hand, as in the present embodiment, when the sensor main shafts 58 and 59 of the left and right magnetic sensors are appropriately inclined forward by an angle θ1 with respect to the traveling direction center line 60, the magnetic sensor 26a inside the turning in the plan view projection is formed. The distance from the center position A to the guide cable of the turning portion 27b is the length of the line segment AD1, and the distance from the center position B of the magnetic sensor 26b outside the turning position to the turning portion 27b.
Is the length AD2 of the line segment.
That is, the line segment AD1 is short, and the line segment AD2 is long. This tendency is caused by the fact that the traveling direction center line 60
Is more likely to be located on the outer side of the turn than the guide cable of the turning portion 27b, so that it becomes more prominent. Therefore, the difference in length between the line segment AD1 and the line segment AD2, that is, the amount of lateral displacement, is apparently larger than in the case where the lines are orthogonal to each other. Therefore, according to the control of the steering angle of the wheels 8, 8 during turning, the drive means increases the inclination angle θ1 substantially in proportion to the increase in the steering angle β (or the steering angle instruction amount). A certain step motor 52, 54 is operated. In this case, the inclination angle θ1 may be controlled so as to increase stepwise by an appropriate amount (appropriate angle) as the steering angle β increases as appropriate, or may be changed so as to change substantially linearly. It may be controlled.

As the radius of curvature of the turning portion 27b is smaller and the bending angle Δ of the turning portion 27b with respect to the straight portion 27a is larger (the steeper the turning portion), the apparent lateral displacement increases. In the steering control for correcting the steering angle, since the control is performed in the direction in which the apparent lateral displacement is reduced, the control of the direction of the magnetic sensor and the steering control are combined, and the turning start portion and the turning middle are performed. The turning steering control that makes the direction of the traveling vehicle substantially along the turning direction can be executed reliably and accurately. Also, the larger the inclination angle θ1 is, the more the apparent
The lateral displacement increases, and the guidance in the turning part
The intersection of the cable and the sensor spindle of each magnetic sensor is before turning
It also has a function to predict the degree of turning because it moves in the direction
Will be obtained.

FIGS. 8 and 9 show that, for example, when the vehicle turns to the left, the steering cable of the traveling vehicle is controlled at the turning portion 27b where the guide cable 27 bends or curves following the straight portion 27a in plan view. In accordance with the turning steering angle β (or the steering angle instruction amount), the sensor main shaft 58 of the magnetic sensor 26a located inside the turning is inclined appropriately θ2 forward with respect to the center line 60 in the traveling direction of the vehicle body, The sensor main shaft 59 of the magnetic sensor 26b located on the outside of the turning is appropriately shifted backward by an angle θ3 with respect to the center line 60 in the traveling direction of the vehicle body.
Adjust and change to tilt only.

In this case, as in the above embodiments, if the center positions A and B of the magnetic sensors 26a and 26b are equidistant from the center line 60 in the traveling direction, the line If an intersection E1 between AB and the traveling direction center line 60 is set, the length of the line segment is AE1 = BE1. On the other hand, assuming that the intersection E2 between the line segment AB and the turning portion 27b, the sensor main axes of the left and right magnetic sensors are set to the center line 60 in the traveling direction by the conventional technology.
, The lateral displacement of the left and right magnetic sensors 26a, 26b with respect to the guide cable of the turning portion 27b in a plan view (in a plan view) is the length of the line segment E
1E2, which is very slight.

On the other hand, as in the present embodiment, the sensor main shaft 58 of the magnetic sensor 26a on the inside of the turning is inclined at an appropriate angle θ2 in the forward direction with respect to the center line 60 in the traveling direction, while the outside of the turning. The sensor main shaft 59 of the magnetic sensor 26b is moved backward θ
When tilted by three, the distance from the center position A of the magnetic sensor 26a inside the turn to the guide cable of the turning part 27b in the projection in plan view is the length AD1 of the line segment and turns from the center position B of the magnetic sensor 26b outside the turn. The distance of the portion 27b to the induction cable is the length AD2 of the line segment. That is,
The line segment AD1 is short, and the line segment AD2 is long. Therefore, the line segment AD1 and the line segment A
The difference in length from D2, that is, the amount of lateral displacement, is apparently large. This tendency becomes more remarkable in the turning start portion because the traveling direction center line 60 is more likely to be located outside the turning than the guide cable of the turning portion 27b.

Therefore, according to the control of the steering angle of the wheels 8 during turning, the inclination angle θ1 is increased substantially in proportion to the increase of the steering angle β (or the steering angle instruction amount). Step motors 52 and 54 as driving means
Activate In this case, as shown in FIG. 10, the inclination angle θ1 may be controlled to change stepwise so as to increase by an appropriate amount (appropriate angle) as the steering angle β increases as appropriate. Control may be performed so as to fluctuate linearly. Since the operation and effect in this case are substantially the same as those of the above-described embodiment, detailed description will be omitted. The smaller the radius of curvature of the turning portion 27b is, the more the linear portion 27a
The larger the bending angle Δ of the turning part 27b with respect to (the steeper the turning part becomes), the larger the apparent lateral deviation amount becomes, so that a function of predicting the degree of turning is also provided.

Although the drive means for changing and adjusting the direction of the magnetic sensor in each of the above embodiments is a step motor, it may be an electromagnetic solenoid or a link mechanism interlocked with a steering mechanism.

[0029]

As described above, according to the present invention, according to the steering angle detection signal from the steering controller,
To change the left and right directions of the pair of left and right magnetic sensors.
Drive means that rotate left and right so that
The larger the detected value of the turning steering angle is,
The main sensor axes of the left and right magnetic sensors in plan view
Are tilted forward with respect to the center line in the traveling direction of the vehicle.
By changing and adjusting the angle to increase
In plan view projection, the difference between the distance from the center position of the magnetic sensor inside the turn to the guide cable of the turning part and the distance from the center position of the magnetic sensor outside the turn to the guide cable of the turn part, that is, the plane In the steering control for correcting the steering angle while the apparent lateral shift amount in the visual projection increases, the control is performed in a direction in which the apparent lateral shift amount decreases, so that the control of the direction of the magnetic sensor and the steering control are performed. Doo is Aima', that the substantially along such pivot steering control the orientation of the traveling vehicle in the turning direction at the turning start portion and turning the middle becomes possible to perform reliably and accurately
It works.

[Brief description of the drawings]

FIG. 1 is a side view of a medicine sprayer.

FIG. 2 is a plan view of the medicine sprayer.

FIG. 3 is a schematic plan view of the steering device 14;

FIG. 4 is a control hydraulic circuit diagram of the steering device.

FIG. 5 is a functional block diagram of a steering control device.

FIG. 6 is an explanatory diagram showing a relationship with the direction of a magnetic sensor in an arc-shaped turning portion in the first embodiment.

FIG. 7 is an explanatory diagram showing a relationship between the direction of a magnetic sensor and a bent portion in the first embodiment;

FIG. 8 is an explanatory diagram showing a relationship with the direction of a magnetic sensor in an arc-shaped turning part in a second embodiment.

FIG. 9 is an explanatory diagram showing a relationship with the direction of a magnetic sensor in a bent revolving portion in the second embodiment.

FIG. 10 is an explanatory diagram showing a relationship for changing the direction of a magnetic sensor.

11A is a front view showing a tilt of a sensor main axis of a conventional magnetic sensor, and FIG. 11B is a view showing a difference in magnetic field strength.

[Explanation of symbols]

 Reference Signs List 1 traveling vehicle 8,8 front wheel 9,9 rear wheel 10 engine 11 traveling transmission mechanism 12 power transmission mechanism 13 power pump 14 steering device 16 hydraulic circuit 26a, 26b magnetic sensor 27 guide cable 27a linear portion 27b turning portion 28 automatic steering control Valve 33 Central processing unit 46, 47, 50, 53, 55 Drive circuit 52, 54 Step motor 56, 57 Angle detector 58, 59 Sensor main shaft 60 Center line in traveling direction

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Kasoya 1-32 Chaya-cho, Kita-ku, Osaka-shi Inside Yanmar Agricultural Machinery Co., Ltd. (56) References JP-A-57-199010 (JP, A) 51-105998 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G05D 1/02

Claims (1)

(57) [Claims] 1. A pair of left and right magnetic sensors mounted on a vehicle body detect an AC magnetic field emitted from a single induction cable disposed along a guidance route, and a steering angle of a steering device is detected by a steering angle detection sensor. In the electromagnetically guided traveling vehicle including a steering control device for performing steering control so as to follow the guidance route, the steering angle of the steering control device
In response to the detection signal, the left and right magnetic sensors
Driving means that turn left and right respectively to change the direction
To increase the detection value of the turning steering angle in the left and right direction.
In proportion to the position of the left and right magnetic sensors in plan view.
Sensor main shaft with respect to the center line in the traveling direction of the vehicle.
An electromagnetic induction-type traveling vehicle, further comprising control means for changing and adjusting the angle of inclination forward .