JPS6334489Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a work vehicle such as a tractor equipped with an automatic steering function.More specifically, the present invention relates to a work vehicle such as a tractor equipped with an automatic steering function. The present invention proposes a working vehicle that can be mounted so as to be movable in the left and right directions within the width of the machine, and is suitable for rotary tilling, plowing, etc. The present invention will be described in detail below with reference to drawings showing an embodiment of the invention on a tractor. Fig. 1 is a partially cutaway left side view of the tractor according to the present invention, Fig. 2 is a schematic diagram of the automatic steering control system,
FIG. 3 is a plan view showing the state during rotary tilling, and FIG. 4 is a plan view showing the state during plowing.
This tractor is configured to perform automatic steering using the boundary INT between the cultivated land CTD and the uncultivated land UCT as a guide for automatic steering. At the front upper part of the bonnet 11, a substantially U-shaped guide rail 13 for guiding and supporting the steering sensor 1 has a central long portion facing the front upper end of the bonnet 11, and its longitudinal direction extends in the left-right direction of the aircraft. The inwardly bent ends of the opposing short portions are connected to the bonnet 11 so that
It is rotatably pivoted and horizontally supported on both the left and right sides. The length of the long portion is slightly longer than the distance between the left and right front wheels 2 (tread). The steering sensor 1 is pivoted to the guide rail 13 so as to be swingable in the vertical direction to a bracket 12 which is fitted onto the guide rail 13 so as to be movable in the left and right directions and to be locked at a desired position. .
Furthermore, the pivoting of the guide rail 13 to the bonnet 11 is such that the guide rail 13 can swing in the vertical direction, and the swing position of the steering sensor 1 with respect to the bracket 12 and the swing position of the guide rail 13 with respect to the bonnet 11 are adjusted. These pivots are connected with appropriate strength so that the swing position does not change due to vibrations of the aircraft. Steering sensor 1 is cultivated land
This device is designed to capture the relative positional relationship between the boundary INT between the CTD and the uncultivated UCT and the aircraft.It has a built-in infrared light emitting element and a light receiving element, and projects the infrared light emitted from the former onto the test object. The latter captures reflected infrared rays from the test object, converts it into an electrical signal, and outputs it. Three optical sensors are arranged in parallel, and the three optical sensors 1a constitute the steering sensor 1. , 1b, and 1c are arranged side by side in this order from the right side to the left side of the fuselage. The detection surface of each optical sensor 1a, 1b, 1c is adjusted by adjusting the vertical swing position of the guide rail 13 and the vertical swing position of the steering sensor 1 itself relative to the bracket 12. It is set so that it faces a point several tens of centimeters in front of the straight line 2a connecting each landing point, and when looking in the left and right direction, the optical sensor 1
The detection surface of a or 1c is directed slightly to the right (or left) from the front of the aircraft, and the detection surface of optical sensor 1b is directed straight ahead of the aircraft. The steering sensor 1 can be moved on the guide rail 13 as described above, but as shown in Fig. 3, when rotary tilling is performed and there is a cultivated field CTD on the left side of the aircraft, the steering sensor 1 or the bracket is moved. 12 is the guide rail 13
the center optical sensor 1b is positioned slightly to the left of the front wheel trajectory. Conversely, if rotary tilling is being performed and the cultivated land CTD is on the right side of the machine, move the steering sensor 1 or bracket 12 to the right edge of the guide rail 13, contrary to what was described above, and move the steering sensor 1 or bracket 12 to the right edge of the guide rail 13, Set to the second position as shown by the dotted line. Furthermore, as shown in Fig. 4, when the plow 20 that flips the cultivated soil to the right side is installed and plowing is performed, and the cultivated land CTD is on the right side (however, unlike in the case of rotary tillage, in this case The boundary INT between the cultivated land CTD and the uncultivated land UCT is between the aircraft centerline CL and the right wheel (for example, near the edge of the bonnet 11), and the steering sensor 1 and the optical sensor 1b are connected to this boundary INT. The plow is set in the third position near the right edge of the bonnet facing the field, and a plow is attached to flip the cultivated soil to the left. It is set in the fourth position near the left edge of the bonnet 11 as shown by the dotted chain line. In Fig. 2, the three optical sensors 1a, 1b, 1c of the steering sensor 1 and the field surface under a state where automatic steering is ideally performed in a case where the CTD of cultivated land by rotary tilling is on the left side. The optical sensor 1c on the left side is
Only the cultivated land CTD, and the optical sensor 1a on the right
The optical sensor 1b detects only the uncultivated land UCT, whereas the intermediate optical sensor 1b detects half the uncultivated land UCT and half the cultivated land CTD. This state of the optical sensor 1b is the same when the cultivated land CTD by rotary tilling is on the right side of the aircraft body, and when the cultivated land CTD by plow cultivation is on the left or right side of the aircraft body,
Of course, the optical sensors 1a and 1b differ depending on whether the cultivated land CTD is located on the left or right side of the aircraft. Now, the optical sensors 1a, 1b,
An electric signal outputted by 1c capturing reflected infrared rays from the field surface is inputted to an analog signal processing circuit 3 via an analog switch group 9. That is, the output of the optical sensor 1a or 1c is input to the input terminal 3A of the signal processing circuit 3 via the analog switch 91a or 92c, and the output of the optical sensor 1c or 1a is input to the input terminal 3A of the signal processing circuit 3 via the analog switch 91c or 92c.
It is arranged so that it can be inputted to the input terminal 3c via a. The optical sensor 1b captures the reflected infrared rays from the field surface and outputs an electrical signal directly to the signal processing circuit 3.
It is configured so that it is input to terminal 3B. 10 is a select switch, and it is used for cultivated land.
If the CTD is on the left side of the aircraft, that is, steering sensor 1
When setting to the 1st or 4th position,
If the first position is the cultivated land CTD, and if the cultivated land CTD is on the right side of the aircraft, that is, if the steering sensor 1 is set to the second or third position, the second position is selected, and the first position is selected. When the second position is selected, only the analog switches 91a and 91c are turned on, and when the second position is selected, the analog switches 92a and 92a are turned on.
Only analog switch 2c is turned on, and the other analog switches are turned off. Although there are differences depending on the grass growth condition, unevenness, wetness, etc. of uncultivated land, generally uncultivated land has a higher reflectance than cultivated land, so the amount of light received by each sensor, in other words, the output signal of each level facing uncultivated land (1a when the select switch 10 is in the first position, 1a when in the second position)
c) is the highest, followed by 1b, which faces both uncultivated and cultivated land, and 1b, which faces cultivated land (1st
The lowest position is 1c when the position is set, and 1a) is the lowest when the second position is set. Therefore, since the select switch 10 and the analog switch group 9 are connected as described above, in any case, a high level signal is sent to the terminal 3A, an intermediate level signal is sent to the terminal 3B, and a low level signal is sent to the terminal 3B. The signals are respectively input to the terminals 3C. If the signals input from each sensor to the input terminals 3A, 3B, and 3C are A, B, and C, respectively, these signals A, B, and C are converted into A-B, B- by the signal processing circuit 3.
Each subtraction process of C, A-C is performed, and further P=(A
-B)-(B-C) is obtained. Now, as shown in Figure 2, if the detection area of the optical sensor 1b connected to the terminal 3B covers half of the uncultivated land UCT and half of the cultivated land, then B=(A+C)/2, so P
= 0, but when the aircraft is moving near uncultivated land (or cultivated land), the uncultivated land (or cultivated land) occupies a larger portion of the detection area of the optical sensor 1b, etc., so B>( A+C)/2[B<(A+
C)/2]. Therefore P<0 [or P>0]
Moreover, since the absolute value of P is determined depending on the magnitude of deviation from the state schematically shown in Figure 2, in short, P is the deviation between 1b and the boundary line INT, which serves as a tracing guide for automatic steering. It serves as a signal that represents the amount of energy. 4 is a steering angle sensor, which measures the centerline CL of the aircraft.
In order to detect the horizontal rotation angle of the left and right front wheels 2, 2, that is, the steering angle, the left and right front wheels 2, 2 are attached to a member such as a knuckle arm that supports the left and right front wheels 2, 2 so that they can be horizontally rotated in conjunction with each other. Specifically, it uses a potentiometer. The output signal D of the steering angle sensor 4 is input to the signal processing circuit 3. However, when the select switch 10 is turned to the first position, the steering angle to the right is positive and the steering angle to the left is negative, and when the select switch 10 is turned to the second position, the steering angle to the left is positive. The select switch 10 is operated so that the steering angle to the right side is negative, in other words, the steering angle to the uncultivated land side is positive, and the steering angle to the cultivated land side is negative. The internal circuit of the signal processing circuit 3 can be switched accordingly. This output signal D is inputted to the differential amplifier in the signal processing circuit 3 together with the above-mentioned deviation amount detection signal P to obtain a signal corresponding to the difference between the two, E=PD. Since this difference signal E is obtained by subtracting the actual steering angle from the deviation amount between the steering sensor and the boundary, it basically represents the required steering amount (a steering amount that is required more than the current state). It has become a signal. For example, in the example shown in Figure 2, the aircraft is traveling straight (D
= 0), if P > 0 [or P < 0], then E > 0 (or E < 0), and the aircraft will be moved to the right side, that is, the uncultivated side (or This means that it is necessary to move it to the left side (that is, the already cultivated side). Further, even if P>0 (or P<0), if D=P due to automatic steering control or other factors up to that point, it means that no further steering is required. Of course, if the ideal steering condition continues, E=P=D=0. 6 is a digital data processing device;
It is a so-called microcomputer equipped with a CPU (for example, a microprocessor μPD556D manufactured by NEC Corporation), an A/D converter, a memory, an input/output interface, and the like. The output signal E of the signal processing circuit 3 is subjected to a predetermined conversion process at the input interface of the data processing device 6, and is converted into digital data according to its level at an appropriate sampling period.
Incorporated into CPU. For example, the level of E is separated and identified into seven levels and then imported into the CPU. The CPU of the data processing device 6 mainly performs steering control based on the signal E, and uses hydraulic drive to horizontally rotate the front wheels 2, 2 to perform steering. Table 1 shows the relationship between the level of the input signal E to the data processing device 6 and steering.

[Table] Times

[Table] Position Turning However, E ₃ > E ₂ > E ₁ > 0
Table 1 shows the progress status of the aircraft when D=0, but as mentioned above, E=P-D.
, P means that the deviation toward the uncultivated side is negative and the deviation toward the tilled side is positive, and D means that the amount of steering toward the tilled side is negative and the amount of steering toward the uncultivated side is positive. Therefore, even if the aircraft travel range deviates significantly toward the plowed side (P is large), when the steering is largely performed toward the uncultivated side (D is large), EE is not necessarily ₃ , but a situation such as E ₁ >E > -E ₁ may occur, and the current state will be maintained without further steering. This is because the aircraft has already been sufficiently steered towards the uncultivated side, and even if it continues in that state, the aircraft will continue to turn in a direction that eliminates the deviation towards the plowed side. . Next, looking at A-C, this difference represents the difference between the reflected light from uncultivated land and the reflected light from cultivated land. Therefore, the difference between these reflected lights will vary depending on the field conditions as described above, but in order to prevent P from changing due to the field conditions, in other words, the difference in the optical sensor 1b is As long as the proportion of light received from uncultivated land and cultivated land is the same, the signal processing circuit 3 The gain of the P amplifier circuit is controlled by A-C. Furthermore, A-C0
If this occurs (for example, if all optical sensors receive reflected light from cultivated or uncultivated land), the signal processing circuit 3 detects this and sends a lamp (Fig. (not shown) is turned on, and A-C is input to the data processing device 6 as it is, so that the data processing device 6 inputs A-C to the data processing device 6.
When the state of C0 continues for a predetermined period of time (about several seconds), a lamp (not shown) for prompting a switch to manual steering mode is made to blink. Now, the hydraulic circuit 7 operates the electromagnetic switching valve by the data processing device 6, and switches the oil passages to advance and retract the plural cylinder rods.
This rod is interlocked and connected to support members for the left and right front wheels 2, and as the rod advances and retreats, the left and right front wheels 2, 2 are interlocked and horizontally rotated in the left and right directions. Therefore, the magnitude control of the steering amount is achieved by intermittently supplying pressure oil to the double-acting cylinder and by varying the duty ratio of this intermittent pressure oil supply cycle. ing. For example, E
If E ₃ , pressure oil is supplied in the rod's advancing direction at a large duty ratio, and -E ₁ E-E ₂ , pressure oil is supplied in the rod's retracting direction at a small duty ratio. It is set as. Reference numeral 8 denotes an input operation unit, which is installed on the driver's seat in order to turn on power to the data processing device 6, switch between automatic and manual steering, and input various data and signals required for automatic steering. It is provided on the front panel 10 in front of the camera 9. This input operation section 8
When the manual steering mode is selected by the operation of It is designed so that it can be steered by operation. That is, the rotation of the steering wheel 5 mechanically switches the electromagnetic switching valve in the hydraulic circuit 7 to advance and retract the double-acting cylinder.
As in the case where the robot is turned, the turning is performed by hydraulic pressure. When rotary tilling is performed using the tractor according to the present invention constructed as described above, the first stroke is first tilled by manual steering, and from the next stroke, the cultivated land and uncultivated land formed in the previous stroke are cultivated. the boundary between
Make automatic steering follow the INT and act as a guide.
As shown in Figures 2 and 3, cultivated land
When the CTD is located on the left side of the aircraft, the steering sensor 1 is set to the first position, and the select switch 10 is set to the first position and the three optical sensors 1a, 1b, 1c of the steering sensor 1 are set to the first position. The output signal is inputted to each terminal 3A, 3B, and 3C of the signal processing circuit 3. As a result, the aircraft has optical sensor 1b as the boundary.
The vehicle will be driven in a manner similar to INT. On the other hand, cultivated land
If the CTD is on the right side of the aircraft, set the steering sensor 1 to the second position, and set the select switch 10 to the second position and set the steering sensor 1r to the second position.
The output signals of the three optical sensors 1a, 1b, and 1c are input to each terminal 3C, 3B, and 3A of the signal processing circuit 3. This causes the aircraft to travel so that the optical sensor 1b follows the boundary INT. When plowing a field back and forth from one side to the other, the cultivated land is reversed left and right on the outbound and return trips, so the steering sensor 1 must be moved between the first and second positions each time. Needless to say, it is necessary to switch the select switch 10 between the first position and the second position. In addition, when cultivating by going clockwise (or counterclockwise) from the outer edge of the field, the select switch 10 is always in the first position (or second position).
(position). It goes without saying that when performing such tillage work, it is necessary to use manual steering to form cultivated land around the four circumferences of the field, and then switch to automatic steering. Next, the case of plowing will be explained. When using the plow 20 that turns the cultivated soil to the right as shown in FIG. 4, the plowing work is performed while going around the field counterclockwise. First, manually steer the machine around the outer edge of the field to form the cultivated field CTD. Thereafter, the steering is switched to automatic steering, the steering sensor 1 is set to the third position, and the select switch 10 is set to the second position, and the optical sensor 1 is set to the second position.
The output signals of a, 1b, and 1c are input to terminals 3C, 3B, and 3A of the signal processing circuit 3. As a result, the aircraft will travel along the boundary INT where the sensor 1b is located to the right of the center line CL of the aircraft, and the uncultivated land to the left of this boundary will be turned over to the right by the plow 20. It will be tilled. When using a plow that turns the cultivated soil to the left, the left and right hands may be reversed as described above, that is, the steering sensor 1 may be set to the fourth position and the select switch may be set to the first position. Furthermore, when carrying out plowing work that goes back and forth from one side of the field to the other, the cultivated land will be flipped left and right on the outbound and return trips, so use a plow that can change the direction of the tilled soil, such as a hill plow. Use, change it for each process,
The steering sensor 1 may be switched between the third and fourth positions, and the select switch 10 may be switched between the second and first positions. As detailed above, the work vehicle according to the present invention includes an optical sensor that projects light onto a detection target, captures the reflected light from the detection target, and outputs an electrical signal according to the level of the reflected light. At least 3 units are installed at the front of the machine so that they can be swung vertically, their light emitting and receiving surfaces can face the field, they can be moved integrally or individually in the left and right directions, and they can be locked at any position. It is characterized by being attached to a guide rail that is longer than the tread that extends in the left and right direction, and configured to perform automatic steering based on the electrical signals output by these optical sensors. All plowing can be done by automatic steering, which has practical benefits in reducing the driver's labor burden and improving work efficiency. In addition, since it is possible to swing the steering sensor 1 in the vertical direction with respect to the bracket 12 and the guide rail 13 with respect to the bonnet 11, the light emitting and receiving areas of the optical sensors 1a, 1b, 1c and the optical sensor can be adjusted as necessary. Optimum sensitivity can be obtained by changing the distance between the field and the field. Further, in the above embodiment, the optical sensors 1a, 1b, and 1c are constructed so as to be guided and moved integrally by the guide rail 13, but they are each attached to a bracket fitted to the guide rail 13 and individually moved in the left and right direction. Of course, it is also possible to allow movement.

[Brief explanation of the drawing]

The drawings are for showing an embodiment of the present invention, and FIG. 1 is a partially cutaway left side view of the tractor according to the present invention, FIG. 2 is a schematic diagram of the automatic steering control system, and FIG. 3 is a schematic diagram of the automatic steering control system. FIG. 4 is a plan view showing the state during rotary tilling, and FIG. 4 is a plan view showing the state during plowing. DESCRIPTION OF SYMBOLS 1... Steering sensor, 1a, 1b, 1c... Optical sensor, 3... Signal processing circuit, 6... Data processing device, 12... Bracket, 13... Guide rail.

Claims (1)

[Scope of utility model registration request] At least three optical sensors that project light onto the detection target, capture the reflected light from the detection target, and output electrical signals according to the level of the reflected light, can be oscillated in the vertical direction, and are capable of projecting and receiving light. It is attached to a guide rail that is longer than the tread that extends in the left and right direction at the front of the machine so that its surface can face the field, and it can be moved in the left and right directions either integrally or individually, and can be locked at any position. A work vehicle is characterized in that it is configured to perform automatic steering based on electrical signals output by these optical sensors.