JPS62194518A - Working vehicle - Google Patents

Abstract

PURPOSE:To prevent the interference of a wave projected from a detector and to attain the accurate control of a working vehicle, by actuating alternately plural detectors and starting the actuation of the next detector after the preceding detector catches the reflected wave or when a prescribed time passed from the start of actuation of the preceding detector. CONSTITUTION:Both front and rear wheels of a working vehicle are supported by a vehicle body and light sensors 15l, 15c and 15r are provided at the left, center and rear sides respectively under a bumper attached to the vehicle body. These sensors 15l-15r incorporate the infrared ray emitting and receiving elements respectively and detect the beams reflected by an obstacle set in the traveling direction of the vehicle to apply them to a control part 30 of an automatic steering device. The part 30 controls the piston rod 27a of a hydraulic double-acting cylinder 27. Then the next detecting actions of the sensors 15l-15r are started when a prescribed time passed after the preceding actions of those sensors that detected previously the reflected waves. Thus the interference of the reflected waves projected from the sensors 15l-15r is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a work vehicle in which, for example, the steering of the machine body or the raising and lowering of a work machine cannot be performed automatically.

[Prior art]

Various automated devices have been proposed for work vehicles such as tractors and combines in order to reduce the labor burden on workers. For example, the front of the aircraft is equipped with multiple optical sensors that emit infrared light toward the front of the aircraft, and the reflected light from obstacles such as trees and rocks in front of the aircraft. The presence or absence of an obstacle or the position of the obstacle with respect to the aircraft is detected by comparing the presence or absence of light reception by each optical sensor or the time from light emission to light reception by each optical sensor, and based on the detection results, the Some tractors are equipped with an automatic steering device that automatically steers the machine to avoid obstacles.

[Problem that the invention seeks to solve]

However, in a tractor equipped with such an automatic steering device, one of the plurality of optical sensors.

The reflected infrared light emitted by one optical sensor may be received by another optical sensor, and it may be mistakenly recognized that there is an obstacle in the detection area of that optical sensor. In the area where the reflected infrared rays or their reflected lights overlap, there is a risk that they may interfere with each other and affect whether or not each optical sensor receives light, resulting in inaccurate steering control. was there. This uses multiple ultrasonic sensors to detect the height of the reaping section relative to the field surface, and based on the detection results, the reaping section is raised, lowered, and rolled relative to the machine body. The same applies to work vehicles.

The present invention has been made in view of the above circumstances, and provides a work vehicle that can accurately perform various controls even when equipped with a plurality of detectors that utilize waves such as infrared rays, ultrasonic waves, and microwaves. The purpose is to provide.

[Means for solving problems]

A work vehicle according to the present invention is intended to solve the above-mentioned problem by operating a plurality of detectors alternately. In a work vehicle that is configured to perform automatic control based on the detection results of a plurality of detectors that operate to detect the presence and/or position of an object by detecting waves, the plurality of detection The detectors are configured to operate in an alternating manner and to start operating the next detector after the previous detector captures the reflected wave or after a predetermined period of time has elapsed since the previous detector started operating. It is characterized by being

[Effect]

In other words, after the first one of the multiple detectors projects a wave such as infrared rays, ultrasonic waves, microwaves, etc., until it receives the reflected wave from the object to be inspected, or if no reception is made. After the previous detector starts operating, the operation of the next detector is stopped until a predetermined time has elapsed to prevent interference of the projected waves emitted from the detector.

〔Example〕

The present invention will be described below based on drawings showing embodiments thereof.

Fig. 1 is a left side view of a tractor, which is a work vehicle according to the present invention, and Fig. 2 is a schematic diagram of its automatic steering system.
1 is a fuselage supported by front wheels 2, 2 and rear wheels 3.3, and the fuselage 1 uses the power generated by a power unit 4 mounted at the front of the aircraft through a mission case 5 installed at its rear. It is transmitted to the rear wheel 3.3 through the rotation of the rear wheel 3.3, and is driven by itself by the rotation of the rear wheel 3.3.

On the other hand, numeral 7 denotes a work machine, which is a rotor, and is attached to the rear end of a three-point link mechanism 6 provided at the rear of the machine body 1. The three-point linkage mechanism 6 is connected to the mission case 5.
By the operation of the hydraulic lift 8 installed on the upper part of the machine, it is raised and lowered with respect to the machine body 1 via a lift arm 9 and a lift link 10, and the rotary 7 is raised and lowered with respect to the field surface.

Now, the left end and center part of the lower side of the bumper 11 attached to the lower front end of the aircraft I when looking in the direction of travel.

At the right end are optical sensors 157! , 15c,
15r is installed.

Each of the optical sensors 151, 15c, and 15r has an infrared light emitting element and a light receiving element built in, and irradiates the object (in this case, an obstacle such as a tree or rock) with infrared rays emitted from the former to detect the object. The latter captures the reflected infrared rays from the specimen, converts them into electrical signals, and outputs them. It is arranged to emit light.

The front wheels 2, 2 are equipped with optical sensors 15 j! , 15c, 1
Based on the detection results of obstacles such as trees and rocks in front of the aircraft 1 by the 5r, the aircraft is automatically steered by advancing and retreating the piston loft 27a of the hydraulic double-acting cylinder 27 in order to avoid the obstacle. .

The front wheels 2, 2 include a front axle 20 which is horizontally fixed to the lower part of the aircraft body 1 with its longitudinal direction being the left and right direction.
A knuckle arm 22 is rotatably supported in a horizontal plane on king pins 21 and 21 attached to both left and right ends protruding from the fuselage 1, with the axial length direction being the up and down direction.
．． 22, it is rotatably supported. At an appropriate position on the upper surface of the front axle 20, one end of a flat plate-shaped rotating member 24 is pivotally supported on a pivot shaft 23 vertically erected on the upper surface of the front axle 20 so as to be rotatable in a horizontal plane. Rotating member 2
The other end protruding forward of 4 is a link member 25.25
and is connected to the front end of the knuckle arm 22.22. Further, one end of an arm 26 is fixed to the upper surface of the central portion of the rotating member 24 in the front-rear direction, and the other end of the arm 26 projects horizontally to the right and is connected to the tip of the piston rod 27a. The part is rotatably supported.

Therefore, the piston loft 27a of the hydraulic double-acting cylinder 27
When the arm advances (or retreats), the rotating member 24 rotates counterclockwise (or clockwise) when viewed from above around the pivot 23 via the arm 26, and rotates via the link members 25, 25. Knuckle arm 22.22, king pin 21.21
Since the front wheel 2.2 is rotated counterclockwise (or clockwise) about the axis, the front wheel 2.2 is steered to the left (or right).

A hydraulic circuit that supplies pressure oil to the hydraulic double-acting cylinder 27 is composed of a hydraulic pump P, an electromagnetic directional switching valve V, and the like. The electromagnetic directional switching valve ■ is a 4-point, 3-position switching type, and when its solenoid SIl (or solenoid Sr) is energized, the pressure oil supplied by the hydraulic pump P is transferred to the hydraulic double-acting cylinder. The piston loft 27a advances (or retracts).
As a result, the front wheels 2°2 are steered to the left (or right).

Solenoid Sj! , Sr are both demagnetized, the cylinder port of the electromagnetic directional valve (■) is blocked, so the supply of pressure oil to the hydraulic double-acting cylinder 27 is stopped, and the front wheels 2, 2 are then demagnetized. The steering angle is maintained at .

The energization control of the solenoids SIN and Sr is performed by a control section 30 using a microcomputer.

The control unit 30 has five input ports (a) to a5 and five output ports b1 to b5.
l, a2. a3 are the respective optical sensors 15 j! ,
It is connected to the infrared receiving elements of 15c and 15r,
When the optical sensors 151 + 15c and 15r receive reflected light from an obstacle, the input ports al+ a2+
a3 becomes high level.

The output of a steering angle sensor 28 using a potentiometer installed at the position of the king pin 21 at the left end of the front axle 20 is supplied to the input port a.

The steering angle sensor 28 receives a positive voltage when the steering wheel is turned to the left, and a positive voltage when the steering wheel is turned to the right, depending on the rotation frequency of the king pin 21, that is, the steering angle of the front wheel 2.2. Outputs negative voltage.

Note that when the vehicle is traveling straight, the output voltage of the steering angle sensor 28 is zero.

The output of the steering angle sensor 28 is subjected to a predetermined conversion process at the input interface of the control section 30, and is taken into the CPU of the control section 30 as digital data E corresponding to the level at an appropriate sampling period.

On the other hand, output ports b, , b2 . b3 is connected to the infrared light emitting elements of the optical sensors 151, 15c, and 15r, respectively, and the output port bl+b2+b
3 turns to high level, the optical sensor 157! .

Infrared light is emitted from each of the infrared light emitting elements 15c and 15r. In addition, the output of the control unit 30) b, , bs
are the solenoid Si of the electromagnetic directional control valve V, respectively.

connected to Sr, and the output capo-t-b++ bs
When the voltage changes to a high level, the solenoids SR and Sr are each excited, and the feeding direction of the pressure oil supplied by the hydraulic pump P is switched as described above.

Now, regarding the automatic steering operation of the work vehicle according to the present invention configured as described above, FIG. 3 is a flowchart showing the control contents of the control unit 30, and FIG. I will explain based on this.

Now, the control section 30 turns on the control start switch 13 installed at an appropriate position on the instrument panel 12 provided at the rear of the power section 4 so as to face the operator seated in the driver's seat DS of the machine 1.
N, input port a5 becomes low level, first the processing of obstacle detection routine X is started, and flag F1.
Reset Fc and Fr.

These flags FA, Fc, and Fr are detected by the optical sensor 15, respectively.
The infrared receiving elements 1° 15c and 15r receive the reflected light from the obstacle, and the respective input ports of the control unit 30 a)
It is sent when 1+32, a3 becomes high level, and when the flags Fl, Fc, and Fr are sent, the optical sensor 15 I! , 15c, 1
This indicates that an obstacle exists within the irradiation range of each infrared ray emitted from the 5r infrared light emitting element.

Next, the control unit 30 sets the output port b1 to a high level so that the left optical sensor 151 emits infrared rays, sets the time T to O, and then starts counting the time T.

Then, the level of the input port at is checked, and if al is low level, it is checked whether the time T has reached a preset reference time T, and even though T>T1, al If a does not change to no\y level, do not process the river, and if a changes to high level before T>T, set flag F1 and proceed to the next process. .

Next, the control unit 30 sets the output boat b2 to the noise level to cause the central optical sensor L5c to emit infrared rays, and at the same time sets the time T to O, and then starts counting the time T.

Then, check the level of input port a2, and if al does not change to λi level even though T > TI, do not perform any processing and set a before T > TI.
When l turns to high level, the flag Fc is set and the process proceeds to the next step.

Next, the control unit 30 sets the output boat b3 to the noise level to cause the right optical sensor 15r to emit infrared rays, and at the same time sets the time T to O, and then starts counting the time T.

Then, check the level of human-powered boat A3 and find that T>T.

If a3 does not change to high level even though it has become, no processing is performed and TNT is returned.

If a3 turns to high level before the flag Fr is set, the process shifts to the obstacle avoidance routine Y after setting the flag Fr.

The reference time T1 is determined by the optical sensors 15A' and 15c.
, Since the time required for the infrared rays emitted from 15r to reach the position of the limit line shown by the dashed-dotted line in Fig. 4 is approximately twice, the limit 1jlL is
If there is an obstacle on the side closer to the detection sensors 15It, 15c, 15r, this is detected and the corresponding flag Fj! , Fc, Fr are cents, but the detection sensors 151, 15c, 15 are lower than the limit line.
If there is an obstacle on the side far away from r, the reference time T1 will be
Since it takes a longer time, the corresponding flags FR, Fc
.

Fr is not sent and the presence of the obstacle is ignored.

In other words, the aircraft 1 is prevented from performing unnecessary avoidance operations with respect to an obstacle that is located sufficiently far in front of the aircraft 1.

Now, in the obstacle avoidance routine Y, the set state of the flag Fly Fc+ Fr is checked first, and if the flags FA and FCI Fr are all in the reset state, the direction of the front wheels 2.2 is not changed. Return to obstacle detection routine X and repeat the above operations.

If some or all of the flags Fly Fc and Fr are set, the sent flag p
A variable indicating a required steering angle by type i and a number is set in advance and placed in one of constants D1 to D5.

That is, when only flag Fr is set,
That is, if an obstacle exists in the area shown as A5 in FIG. is assumed to be D=D1.

Furthermore, when the flags Fc and Fr are in the set state, that is, when there is an obstacle in the area indicated by A, D=D, and the flags Fc and Fl are in the cent state. In other words, if there is an obstacle in the area indicated by A2, D=D2, and the flags Fffi, Fc,
When all Fr are set, that is, when an obstacle exists within the area indicated by A3, D=D3.

D1 to D5 are set so that D4<D5×0<Dl<D2<D3.

Although it is possible that an obstacle exists in the area shown as A6 in FIG. 4, that is, only the flag Fc is in the cent state, in reality, the obstacle is detected in the area A1 to A5. Since it is impossible for an obstacle to suddenly appear within the area indicated by a circle, the case where only the flag Pc is set is not considered in this embodiment.

Now, after D is set to one of the values D1 to D5, the positive or negative state of D is checked, and if D is positive, this D and the steering angle sensor Input from 28,
Does not correspond to the steering angle of the front wheels 2.2.

Data E is compared.

Then, in order to intermittently energize the solenoid S/ of the electromagnetic directional control valve V until E≧D, the output boat b is set to a high level and the front wheels 2.2 are steered to the left to avoid the obstacle. do.

If D is negative, D and E are similarly compared, and the output boat b5 is set to a high level in order to intermittently energize the solenoid Sr of the electromagnetic directional control valve V until E≦D. , steer the front wheels 2.2 to the right to avoid the obstacle.

For example, if the presence of an obstacle is detected within the area indicated by A1 in Figure 4, D=D+ (a positive value with a small absolute value)
Therefore, the steering condition of the front wheels 2°2 at that time is straight forward,
That is, when E=O, DIE occurs, the solenoid SI1 is excited for a short time, and the front wheels 2, 2 are steered to the left. When the front wheel 2.2 is steered slightly to the left, the value of E increases to a positive value, and E≧D, and the steering operation is stopped.

Also, if the presence of an obstacle is detected within the area indicated by A4, D=D (a negative value with a large absolute value), so it is necessary to steer significantly to the right. At that time, the front wheel 2.2 was significantly steered to the right, and D≧
If E, do not energize solenoid Sr (maintain the current steering state).

Note that if an obstacle is detected within the area indicated by A3, that is, approximately in front of the aircraft 1, in this embodiment, D=Di (the largest positive value) and the front wheels 2°2 are steered to the left. However, the value of D3 may be configured as a negative value with a large absolute value to cause steering to the right.

After performing the predetermined steering operation and avoiding the obstacle as described above, the process is transferred to the obstacle detection routine X again, and the optical sensor 15 j! , 15c, and 15r, respectively, and the control unit 30 operates to detect a new obstacle.

〔effect〕

As detailed above, in the work vehicle according to the present invention, the infrared rays projected by the optical sensor, which is a detector, are reflected by the obstacle, which is a test object, until the infrared rays are received by the optical sensor. If the sensor does not receive light, it will stop emitting light from other photosensors until a predetermined period of time has elapsed, so it will not receive reflected light other than its own emitted light and misidentify an obstacle. Further, in a region where infrared rays from a plurality of optical sensors overlap, there is no mutual interference, and excellent effects such as being able to accurately detect the position of an obstacle are achieved.

In this embodiment, an optical sensor using infrared rays is used as a detector, but a detector using ultrasonic waves, microwaves, etc. may also be used.

In addition, in this embodiment, in order to avoid obstacles,
We have described a J-steered tractor, but a pair of ultrasonic sensors are installed on the left and right sides of the lower part of the reaping section to project ultrasonic waves toward the field surface. Other work such as a combine harvester configured to detect the distance from the screen, move the reaping section up and down based on the average value of those detection results, and roll the reaping section based on the difference between those detection results. Needless to say, similar effects can be achieved in commercial vehicles as well.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a left side view of a tractor that is a working vehicle according to the present invention, and FIG.
The figure is a schematic diagram of the automatic steering system, FIG. 3 is a flowchart showing the control contents of the control section, and FIG. 4 is an explanatory diagram of the automatic steering operation. ■...Airframe 2...Front wheel 3...Rear wheel 157!
, 15c, 15r... Optical sensor 27... Hydraulic double acting cylinder 28... Steering angle sensor 30... Control section P... Hydraulic pump ■... Electromagnetic directional control valve

Claims (1)

[Claims] 1. A plurality of detectors that operate to detect the presence or absence of a test object and/or its position by capturing reflected waves from the test object of the waves projected onto the test object. In a work vehicle that is designed to perform automatic control based on the detection results of A work vehicle characterized in that it is configured to start the operation of the next detector after a predetermined period of time has elapsed from the start of the operation.