JPH0410721Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to work vehicles such as tractors, and more specifically, the purpose of the present invention is to provide a work vehicle that automatically rotates the machine to reduce the labor burden on the driver. do. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing an embodiment of a tractor with an automatic steering function. FIG. 1 is a partially cutaway left side view of a tractor according to the present invention, and FIG. 2 is a schematic block diagram of a device involved in automatic steering and rotation. During plowing work, this tractor automatically steers by following the boundary INT between cultivated and uncultivated land as a guide, and when it reaches the edge of the field, it automatically turns around on the headland, and then starts plowing while automatically steering again. It is structured as follows. As shown in Figure 1, a pair of steering sensors 1 are installed on the left and right sides of the aircraft to detect boundary INT at the upper front part of the side of the bonnet, and the detection surfaces are located several tens of centimeters in front of the landing point of the front wheels. It is designed so that it will face you.
The steering sensors 1l and 1r have an infrared light emitting element and a light receiving element built in, and the infrared rays emitted from the former are projected onto the object to be inspected, and the latter captures the infrared rays reflected from the object, which is then converted into electricity. It consists of three optical sensors that convert and output signals, and are arranged in parallel in the horizontal direction of the machine.Here, the electric signals are not binarized and processed; The level of this electrical signal is representative of the state of reflection at the signal and is input to the signal processing circuit 3 via analog switches 12l and 12r. This analog switch 1
2l and 12r are the left optical sensor 1l when the cultivated land CTD is on the left side of the aircraft;
When the CTD is on the right side of the aircraft, the right optical sensor 1r is turned on and off by the select switch 81 of the input operation section 8 so that it is used. That is, in the former case, the analog switch 12l is turned on and the analog switch 12r is turned off, and in the latter case, the analog switch 12l is turned off and the analog switch 12r is turned on to selectively output the output signal of the optical sensor 1l or 1r. The signal is supplied to the processing circuit 3. Figure 2 shows the relative positional relationship between the three optical sensors 1a, 1b, 1c of the steering sensor 1r and the field surface under conditions where automatic steering is ideally performed. The optical sensor 1c (on the cultivated land side) detects only the cultivated land CTD, the intermediate optical sensor 1b detects the cultivated land CTD and half the uncultivated land UCT, and the innermost optical sensor 1a detects the uncultivated land UCT.
The state is such that only the following objects are targeted for detection. 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 optical sensors 1a, 1b, 1
Regarding the amount of light received by each of c, in other words, the level of each output electric signal, 1a is the highest, 1b is the next, and 1c is the lowest. The output electrical signals A, B, and C of the optical sensors 1a, 1b, and 1c are converted into A-B, B-C by the signal processing circuit 3.
Then, P=(A-B)-(B-C) is obtained by performing each subtraction process, and then subtracting the difference between them. Now, as shown in Fig. 2, if the detection area of the intermediate optical sensor 1b covers half of the cultivated land CTD and half of the uncultivated land UCT, B = (A + C) / 2, so P = 0. , when the aircraft is moving near uncultivated land (or cultivated land), the uncultivated land (or cultivated land) includes a larger portion of the detection area of the optical sensor 1b, so B>(A+C)/2. [or B<(A+C)/2]. Therefore, P<O [or P>O], and the absolute value of P is determined depending on the magnitude of deviation from the state shown in Fig. 2, so in short, P is the difference between the steering sensor 1 and the automatic steering tracing guide. This signal represents the amount of deviation from the boundary line INT. Furthermore, the output electric signals A and C of the optical sensors 1a and 1c are used as signals for switching from automatic steering to automatic rotation and from automatic rotation to automatic steering. That is, in the signal processing circuit 3, first A-C
is determined, and then the value of A-C is set to a predetermined reference value.
It is compared with Th, and if it becomes lower than this reference value Th, a high level signal is output as the rotation command signal F. In other words, this tractor performs automatic steering using the boundary INT as a guide, but the reason why the outputs of the optical sensors 1a and 1c, which are supposed to detect uncultivated land and cultivated land respectively, are equal is because the detection areas of both are the same. In both cases, it is assumed that the headland, which is uncultivated land, has been reached and the movement is performed.
This rotation operation continues until a rotation end command signal G, which will be described later, is issued. Further, the output electric signals A and C of the optical sensors 1a and 1c are used as signals for switching from automatic rotation to automatic steering. That is, optical sensor 1
When the detection areas of a and 1c reach the headland, a rotation operation is performed, but in the middle of this rotation operation, analog switch 1 is
2l and 12r are used to switch the steering sensors, and when the rotation progresses further and the difference A-C between the output signals of the optical sensors 1a and 1c becomes higher than the reference value Ts, the outermost optical sensor 1c has already been switched. A high-level signal is output as an automatic rotation end command signal G to indicate that the cultivated land is detected, thereby terminating the automatic rotation operation. This standard value Ts is
This value is sufficiently larger than the reference value Th.
In this state, the optical sensor 1c has detected cultivated land, and the other optical sensor 1a has detected uncultivated land, so the automatic steering following the completion of the rotation is as follows:
The process starts in a state where the boundary between cultivated land and uncultivated land between the detection areas of these optical sensors 1a and 1c can be followed. Therefore, the aircraft flies straight ahead without making unnecessary movements. Reference numeral 4 denotes a meandering angle sensor, which can horizontally rotate the left and right front wheels 2 in conjunction with each other in order to detect the horizontal rotation angle of the left and right front wheels 2 with respect to the center line in the left-right direction of the aircraft body, that is, the meandering angle. Specifically, a potentiometer is used to obtain an output signal corresponding to the heaviness angle. Therefore, the output signal D of the heave angle sensor 4 (however, if the heave angle toward the plowed side is negative,
The meandering angle to the uncultivated side is assumed to be positive) is input to the data processing device 6 for turning control, which will be described later.
The signal is input to the signal processing circuit 3, and is input 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. This difference signal E is obtained by subtracting the actual heave angle from the deviation amount between the steering sensor and the boundary line, so in short, it is the required heave removal amount (the required heave removal amount more than the current state) It is a signal representing the For example, if P>0 (or P<0) even though the aircraft is moving straight (D=0), E
>0 (or E<0), which means that it is necessary to move the machine toward the uncultivated side (or the cultivated side) by an amount corresponding to the absolute value. Also 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 snake removal is required. And if the ideal steering condition continues, E
Of course, =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 stages, and the result is imported into the CPU. The CPU of the data processing device 6 mainly controls the driving and switching of the steering wheel 7 so as to perform steering control based on the signal E, and uses the hydraulic drive to control the front wheels 2 and 3.
horizontally rotates to remove snakes. The relationship between the level of the input signal E to the data processing device 6 and the snake removal is shown in Table 1.
It is as follows.

[Table] Table 1 shows the progress status of the aircraft when D=0, but as mentioned above, E=P−D
, P has a negative deviation toward the uncultivated side and a positive deviation toward the plowed side, and D has a negative heaving angle toward the plowed side and a positive meandering angle toward the uncultivated side. Therefore, even if the machine advance range is largely deviated toward the plowed side (P is large), when the snake removal is largely carried out toward the uncultivated side (D is large), Not necessarily E
E ₃ may not occur, but a situation such as E ₁ >E > -E ₁ may occur, and the current situation will be maintained without further meandering. However, the meandering to the uncultivated side has already been sufficiently carried out, and even if the situation continues, the aircraft will continue to turn in the direction of eliminating the deviation to the plowed side. . In the hydraulic power snake trapping device 7, energization of the solenoids of two solenoid valves 71, 72 is controlled by the output of the data processing device 6, and the square solenoid valves 71, 7
A double-acting hydraulic cylinder whose piston rod is connected to a front wheel knuckle arm, etc., is configured such that pressure oil is supplied and discharged through these electromagnetic valves 71 and 72 by energizing the solenoid No. 2. 70 is activated to perform snake removal to the left or right. The structure is such that snake removal can be similarly performed by manually rotating the steering wheel 5. In order to supply pressure oil to the hydraulic cylinder 70 intermittently, solenoid valves 71 and 72 are driven intermittently, and the amount of snake removal is determined by the duty ratio of this intermittent pressure oil supply cycle. This is achieved by varying the size. That is, for example, E
If E ₃ , pressure oil is supplied in the direction in which the rod advances at a large duty ratio, and -E ₁ E>-E ₂
In this case, the operation is performed at a small duty ratio. Therefore, if the required heaving amount represented by E is small, hunting due to overcorrection will be prevented, and if it is large, the direction will be corrected quickly. Reference numeral 8 denotes an input operation section provided on the front panel 10 in front of the driver's seat, which is used to turn on/off the power, switch between automatic and manual steering, and switch between automatic and manual rotation in order to operate the circuit shown in Figure 2. It is configured to input various data and signals required for switching, automatic steering, and rotation. In the figure, 81 is a selection switch for manual switching of the analog switches 12l and 12r, and 82 is an automatic selection switch for switching the analog switches 12l and 12r.
This is a toggle switch for switching to a manual mode, and when the switch 82 is set to the manual mode, turning is performed by operating the steering wheel 5 or the like. The control device 9 is configured to control the left and right sides independently or simultaneously by the output of the data processing device 6, and the data processing device 6 controls the solenoid valve 91l.
Alternatively, when a control signal is issued to open the brake shoe 91r, pressure oil is supplied to the hydraulic cylinder 92l or 92r to operate the brake shoe 93l or 93r. In addition, the left and right brake pedals 90
Even when the solenoid valves 91l and 90r are pressed, the solenoid valves 91l and 91
By switching r, brake shoes 93l and 93r can be operated. 11 is a lifting device for the lift arm 110;
It consists of a solenoid valve 111 that is opened and closed controlled by the output of the data processing device 6, a hydraulic cylinder 112 that lifts the lift arm 110 using pressure oil supplied via the solenoid valve 111, and is operated by manual operation of a lift lever 113. Lifting and lowering of the lift arm 110, that is, a working machine 114 such as a rotary connected to it
(See Figure 3). In addition,
The lift arm and the work machine are lowered by the weight of the work machine etc. by switching the solenoid valve 111 so that the pressure oil in the hydraulic cylinder can be returned to the tank. 13 is a transmission, which has 3 forward speeds, 2nd speed, and 1 forward speed.
Switches F3 and F that command speed, neutral, and reverse
2, F1, N and R, a solenoid valve 131 whose switching is controlled by the operation of each switch, and the solenoid valve 131
It consists of a power shift transmission 132 having a clutch that is engaged by pressure oil supplied through the solenoid valve 131, and the switching control of the solenoid valve 131 is also performed by the output of the data processing device 6. There is. Next, sensors for rotation operations will be explained. First, regarding the amount of heave removal, the output signal D of the heave angle sensor 4 is taken into the data processing device 6. Next, micro switches 115, 116, and 117 are provided around the lift lever 113 to detect whether the lift arm is in the lifting, stopping, or lowering operation positions, and the on/off state of each is sent to the data processing device 6. It is designed to be taken in. Furthermore, micro switches 118 and 1 are provided at the upper and lower limits of the rotation of the lift arm 110 to detect the rotation state.
19 is provided, and its on/off state is also input to the data processing device 6. The state of the transmission 13 is switch F3, F2, F.
The gear position is detected by inputting the operating states of 1, N, and R into the data processing device 6. Regarding the braking device 9, a hydraulic cylinder 92l,
Micro switches 94l and 94r are installed on 92r to detect the advance and retreat of the rod.
The data processing device 6 is configured to take in the on/off state of the. When performing rotary tillage with the proposed machine configured as described above, a rotary is attached to the rear of the machine as a working machine, and after lowering the rotary with the lifting lever 113, the CTD of the cultivated land parallel to the ridge is moved.
The plowing machine is run to perform tilling work so as to form a plow (see Fig. 3). After completing one stroke of plowing work and making a turn around the headland, the aircraft is positioned as shown by the dashed line in FIG. 3, and then the optical sensor is started. In this case, since the cultivated land CTD is on the right side of the machine, the select switch 81 of the input operation section 8 turns off the analog switch 12l and turns on the analog switch 12r to activate the optical sensor 1r on the right side. This will cause the aircraft to automatically
Cultivation work will be carried out by driving along the boundary INT between the UCT and the cultivated land CTD. After completing one cycle of tilling, the detection area of the sensor 1c changes from the cultivated land CTD to the uncultivated land UCT, such as headland, on the outermost side of the optical sensor 1r.
The output electric signals A and C of a and 1c are approximately equal, and the difference A-C is a value lower than the reference value Th, and the signal processing circuit 3 outputs the rotation command signal F to the data processing device 6. . The data processing device 6 receives this signal and outputs a predetermined signal to the lifting device 11, the transmission device 13, the braking device 9, and the snake removing device 7. That is, the solenoid valve 111 of the elevating device 11 is set to the open position and the lift arm 110 is raised to raise the rotary, and the transmission gear 13 is set to the first forward speed to decelerate. Furthermore, the braking device 9 and the snake remover 7 also operate, but in this case, the steering sensor 1r
is selected, and there is uncultivated land to the left of the aircraft that will be cultivated in the next step, so the aircraft operates to turn the aircraft to the left. That is, the solenoid valve 9 of the braking device 9
1l is in the open position and the left brake shoe is 93l.
At the same time, the hydraulic cylinder 70 is operated via the solenoid valve 71 or 72 to rotate the front wheel to the left. As a result, the aircraft moves up the rotary and makes a left turn, but in the middle of this turning operation, the analog switch is switched by operating the select switch 81. That is, in the next step, since the cultivated land is on the left side of the aircraft, the analog switch 12l is turned on and the analog switch 12r is turned off to turn on the left steering sensor 1l. At this time, the turning operation continues, and the aircraft continues to turn to the left, so that the outermost sensor 1c of the left steering sensor 1l will soon detect the cultivated land. As a result, optical sensor 1
The difference A-C between the electrical signals a and 1c becomes higher than the reference value Ts, and the signal processing circuit 3 outputs a rotation end signal G to the data processing device 6. Based on this signal, the data processing device 6 determines that automatic steering is now possible and terminates the rotation and restarts automatic steering. That is, the brake device 9 releases the brake, the snake remover 7 returns the front wheels to the straight-ahead position, and the lifting device 11 lowers the rotary, and then the transmission device 1
3 returns to the driving speed gear during automatic steering. This allows the aircraft to move between the uncultivated land UCT and the cultivated land CTD.
Plowing work will be carried out in accordance with INT, and when the headland is reached, the same operations as those described above will be carried out. As described in detail above, the work vehicle according to the present invention is a work vehicle configured to perform an automatic rotation operation, and is equipped with a sensor capable of detecting the surface condition of uncultivated land and cultivated land, as well as a signal processing circuit. Further, a data processing device for calculating signals from the uncultivated land/cultivated land detecting means is provided, and a rotation command signal from the uncultivated land/cultivated land detecting means is used to control the rotation of the rotary vehicle. The rotary is raised and the transmission is decelerated, and the rotary is lowered and the transmission is returned to the traveling speed stage in response to the rotation end signal from the uncultivated land/cultivated land detection means. In addition, if automatic steering is also possible as in the above embodiment, there is no need to steer the aircraft along the cultivated land, and automatic operation becomes possible. During automatic rotation between tasks, the detection means can issue a rotation command and a signal indicating the end of the rotation to determine the exact start and end positions of the automatic rotation, thereby ensuring precise rotation. It is possible to start and end the operation, and on the other hand, it detects the absence of the crop row to be detected for a certain period of time, starts the rotation, and re-detects the presence of the crop row for a certain period of time. Compared to the column detection method that detects the end of a cycle, it is possible to detect the start and end of a cycle on-time without any time lag and issue a signal, so there is no loss in the cycle and a short time is required. It can be done. Also,
The raising and lowering of the rotary and the deceleration and speed-up of the transmission can be performed automatically when the rotation starts and ends, and the rotation radius and rotation time can be significantly reduced. It has a remarkable effect that promises fully automatic and excellent agricultural work.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention.
The figure is a partially cutaway left side view of the tractor according to the present invention.
FIG. 2 is a schematic block diagram of the automatic steering and rotation control device, and FIG. 3 is an explanatory diagram of the operation. 1l, 1r... Steering sensor, 3... Signal processing circuit, 6... Data processing device, 7... Snake removal device, 9
...Braking device.

Claims (1)

[Scope of utility model registration request] A work vehicle configured to perform an automatic rotation operation is equipped with a sensor capable of detecting the surface condition of uncultivated land and cultivated land, and is provided with uncultivated land/cultivated land detection means having a signal processing circuit,
A data processing device is provided to calculate the signal from the uncultivated land/cultivated land detection means, and the rotary is raised and the transmission is decelerated by the rotation command signal from the uncultivated land/cultivated land detection means, Based on the rounding end signal from the cultivated land/already cultivated land detection means,
A work vehicle characterized in that it is configured to lower a rotary and return a transmission to a traveling speed gear.