JPH0146082B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an automatic steering device for a transplanting machine, and more specifically, the present invention relates to an automatic steering device for a transplanting machine, and more specifically, the present invention uses a seedling sensor that detects the relative positional relationship between a planted seedling and the machine body, which is basic information for steering control, by contacting a planted seedling and emitting a predetermined signal. This paper proposes an automatic steering system for transplanted machines that takes into account the In a transplanting machine such as a rice transplanter, it is extremely important to plant seedlings in an orderly straight line in order to ensure uniform growth of the seedlings and mechanize the harvesting process. For this purpose, various automatic steering devices have been proposed in the past, but their steering control methods can be broadly divided into those that follow specially installed guidance means such as electromagnetic waves emitted from cables buried underground. , there are those that imitate the rows of already planted seedlings. In the latter method, it is necessary to understand the relative positional relationship between the already planted seedlings and the aircraft.
For this purpose, optical sensors have mainly been employed. However, optical sensors have the drawback of being susceptible to malfunctions due to dirt and the like adhering to the light-receiving surface, which has been an obstacle to putting them into practical use. The present invention has been made in view of the above circumstances, and uses electrical resistance of the seedlings to electrically detect the presence of seedlings, thereby accurately determining the relative positional relationship between the row of planted seedlings and the machine body. It is an object of the present invention to provide an automatic steering device for a transplanted aircraft that can perform steering control without malfunction. An automatic steering device for a transplanting machine according to the present invention is an automatic steering device for a transplanting machine that captures the relative positional relationship between the already planted seedlings and the machine body and causes the machine to travel along a row of already planted seedlings. A plurality of conductive touch rods are installed in a direction perpendicular to the direction of travel of the aircraft so as to extend in the direction and touch the already planted seedlings;
It is equipped with a comparator provided corresponding to each touch rod,
The input terminal of each comparator is connected directly or indirectly to each touch rod, and is biased to a potential slightly different from its reference voltage terminal using a high-resistance resistor. The comparator output is configured to be inverted when it comes into contact with a planted seedling, and the relative positional relationship is recognized based on a data pattern consisting of a plurality of comparator outputs using these comparator outputs as input. The vehicle is characterized by comprising a data processing device that determines the amount of steering. The present invention will be described in detail below based on drawings showing embodiments thereof. FIG. 1 is a left side view of a rice transplanter equipped with an automatic steering device according to the present invention, in which traveling drive and speed change are performed by a hydrostatic drive device, and steering is performed from left to right. This is done by cutting off the pressure oil supply to one of the hydraulic motors attached to each of the front wheels, and the pressure oil supply can be stopped manually by rotating the steering wheel 101 or by using a solenoid valve. This can be done automatically by energizing the solenoids 2l and 2r (see Figure 8). The planting section 103 is connected to the front of the fuselage body by one top link 104 and a pair of left and right lower links 105 (only the left one is shown in the figure).
Further, the lift arm 106 (only the left one is shown in the figure) connected to the left and right lower links 105 is moved up and down by vertical movement. Four sets of seedling sensors are attached to the left and right lower links 105, respectively. That is, lower link 1 is connected to the left seedling sensor as shown in FIG.
A sensor box 108 is attached to the tip of an arm 107 made of a pipe that extends outward from the fuselage. It is set up. The touch rods 81 to 84 are made of thin conductors, the front and rear ends thereof are curved upward, the straight part in the middle is approximately 150 mm, and the front end is fixed within the sensor box 108, and the inner end thereof is curved upward. connected to electronic circuits. The touch rods 81 to 84 are spaced approximately 50 mm apart in the left and right directions of the aircraft.
3 and 84 are arranged side by side from left to right in this order, and in order to ensure this separation dimension, horizontal rods 1 made of electrical insulators are provided at the front curved part of the straight part and the rear end part.
09, 109 in an appropriate manner, and is constructed in the shape of a sled as a whole. and four tentacles81
The contact rod group consisting of ~84 can come into contact with the upper part of the seedlings constituting the already planted seedling row closest to the aircraft among the already planted seedlings group when the planting part 103 is lowered and its float 110 is landing on the water. The length of the arm 107 and the length of the touch rod itself are determined as follows. Next, the electronic circuit connected to the touch rods 81 to 84, which is the main part of the present invention, will be explained. FIG. 3 is a schematic circuit diagram showing its basic configuration, and this circuit is provided for each touch rod. 11 is a comparator, 12,
13 is a voltage dividing resistor, 14 is a high resistance value (e.g.
10MΩ). positive potential
Resistors 12 and 13 are connected in parallel between the Vcc line and the body ground of the aircraft, and the positive and negative power terminals of the comparator 11 are connected to the line and the body ground, respectively. The +input terminal of the comparator 11 is connected to the intermediate terminal of the resistor 12, and the -input terminal is connected to the touch rod, for example 81, and is also connected to the intermediate terminal of the resistor 13 via the resistor 14. By appropriately determining the position of the intermediate terminals of the resistors 12 and 13, a bias is applied so that the − input terminal, which becomes the input terminal of the comparison target signal in this case, is slightly higher than the + input terminal, which serves as the reference voltage terminal. It has been done. Now, the surface resistance value of the planted seedling Z from the base to the tip that comes into contact with the touch rod 81 etc. is in the range of approximately 50MΩ to 100MΩ, depending on its moisture absorption state or moisture adhesion state, and is generally around 80MΩ. ing. The roots of the seedlings that have already been planted are located in water in the field and their potential is the same as the body ground, so when the tip of the seedling comes into contact with the contact rod 81, etc., the rod is grounded through the high resistance of the already planted seedling Z. , the potential of the - input terminal of the comparator 11 becomes slightly lower than the potential of the + input terminal, and the output terminal OUT of the comparator 11 changes from the low level when the planted seedlings Z are not in contact with each other to the high level. become. Note that the value of the resistor 14 is preferably set to about 10 MΩ as described above, taking into consideration the resistance value of the seedlings and the stability of the circuit. Figure 4 shows a bias resistor 14 with a high resistance value connected between the + and - input terminals of the comparator 11, and a bias resistor 14 connected in series between the positive potential Vcc line and the body ground.
Comparator 1
1, and is connected to the + input terminal of resistor 1.
In step 4, the - input terminal is biased to have a slightly higher potential than the + input terminal, and the contact between the touch rod 81 and the planted seedlings Z reverses the potential levels of both input terminals. This is exactly the same as the circuit shown in FIG. 3 in that the output of the output terminal OUT of the comparator 11 is inverted accordingly. The circuit shown in FIG. 5 is the same as the circuit shown in FIG. 4 to which a resistor 15 and diodes 16, 16 are added to protect the comparator 11. That is, anti-parallel diodes 16, 16 are connected in parallel to the bias resistor 14, and a 100 KΩ resistor 15 is interposed between the touch rod 81, etc. and the negative input terminal of the comparator 11. This prevents excessive current from flowing in and excessive voltage from being applied. The circuit shown in FIG. 6 is a modification of the circuit shown in FIG. 5 to provide higher sensitivity. That is, the resistor 13a,
A resistor 13c is interposed between comparator 11 and 13b.
The + input terminal of the bias resistor 14 is connected to the intermediate connection point between the resistors 13a and 13c, while the other end of the bias resistor 14 whose one end is connected to the - input terminal is connected to the resistor 13c and 13c.
It is connected to the intermediate connection point with b. As a result, the potential of the one end of the bias resistor 14, that is, the - input terminal, can be brought closer to the potential of the + input terminal,
Even when the livestock resistance value of the already planted seedlings Z is high, the comparator output can be reliably reversed by contact with the touch rod. FIG. 7 is a block diagram schematically showing the main parts of the electronic circuit of the device of the present invention. In this embodiment, the circuit of the seedling sensor is simplified from the circuit shown in FIG. protection diode 1
6 and 16 are connected in parallel between the + and - input terminals of the comparator 11, and a protective resistor 15 is connected between the - input terminal and the touch rod.
The structure is such that the Of course, even with such a configuration, a sensitivity that does not cause any problem in practical use can be obtained. In this way, one seedling sensor consists of one touch rod and electronic circuits such as the comparator 11 and bias resistor 14 connected to it. The group of touch rods provided in
The seedling sensors related to Nos. 1, 82, 83, and 84 are represented as 81l, 82l, 83l, and 84l, respectively. On the other hand, the structure of the right hand group 8r is the same as the one on the left, with the contact rods 81, 82, 83, 81, 82, 83,
They are arranged in the order of 84. And the right handle 8
The seedling sensors 1, 82, 83, and 84 are represented by 81r, 82r, 83r, and 84r, respectively. The signals to be received are 81l and 81r, 82l and 82r, 83l
and 83r, and 84l and 84r, respectively, are input into pairs as a pair to the input ports _P10 to _P13 of the data processing device 1, which is the control center of the device of the present invention. The sensor unit 80l consisting of the seedling sensors 81l to 84l and the sensor unit 80r consisting of the seedling sensors 81r to 84r are respectively attached to the left and right lower links 105 as described above. It is stored in a suitable place in the main body, for example, in the operation column 111. The seedling sensor is highly sensitive and detects the presence of high-resistance planted seedlings when they come in contact with the touch rod, so the end of the touch rod on the sensor box side has a structure with a covering and a grounding external conductor, like a shielded wire. , and comparator 11,
It is best to use shielded wires for the conductors used to connect to the bias resistor 14, etc. to prevent malfunctions due to external interference, and for the same purpose, it is best to shorten the distance between the touch rod and the comparator 11. However, since the output impedance of the comparator 11 is low, the wiring from the comparator 11 to the data processing device 1 (two for power supply per sensor unit, one for output per seedling sensor) is There is no need for a shield, and there is no problem even if the length is long. A pipe-shaped arm 107 is used for this wiring. Note that the mounting position of the sensor unit is not limited to the above-mentioned lower link, but may be arranged on the side of the planting section bumper 103' in front of it so that information for steering can be obtained more quickly. The data processing device 1 is a so-called microcomputer, and in this embodiment, a one-chip microcomputer 8748-8 manufactured by Intel Corporation in the United States, which is also equipped with a memory device, is used. The data processing device 1 is programmed to recognize the relative positional relationship between the planted seedlings and the machine body in the following manner. That is, depending on the planting process, the planted seedlings Z will come into contact with the contact rod group 8l or 8r of either the left or right sensor unit 80l or 80r, but in either case, only the leftmost contact rod 81 will come into contact with the seedlings Z. When the seedling comes into contact (that is, when only the output of the comparator 11 connected to the touch rod 81 is inverted and this is detected by the data processing device 1), it is recognized that the aircraft is in a state where it is largely biased to the right. In other words, if the row of already planted seedlings is to the left (or right) of the aircraft, it is recognized that the aircraft is too far away from (or too close to) the row of already planted seedlings. Next, when the touch rods 81 and 82 come into contact with the planted seedlings, it is recognized that the aircraft is slightly biased to the right. Further, if the touch rods 82 and 83 are in contact with the planted seedlings, the machine maintains a desired distance from the row of planted seedlings and recognizes that the machine's position is normal. Furthermore, if a planted seedling comes into contact with the touch rods 83 and 84, the aircraft will be slightly biased to the left, and if a planted seedling comes into contact only with the touch lever 84, the aircraft will be greatly biased to the left. Recognize that there is. Then, depending on each situation, the steering angle required to make the vehicle travel along the rows of already planted seedlings is determined as shown in Table 1.

[Table] However, the positive and negative signs of the steering angle are positive to indicate steering to the left and negative to indicate steering to the right, and θ ₂ >
Let θ be ₁ . In addition, in order to prevent the control system from hunting due to unnecessary operation and the riding comfort to deteriorate, the contact state between the seedling and the touch rod that does not apply to each of the cases 1 to 5 in Table 1 is If it appears, the steering angle is determined to be smaller (if there are four levers as in the embodiment, the steering angle is 0). For example, if only the touch rod 82 or 83 is touched, 0, 81,
If it touches 82, 83 or 82, 83, 84, it is set to 0. In this way, seedling sensors 81l to 84l or 81r
When the steering angle is determined based on the combination of the outputs of ~84r, that is, the output pattern, the data processing device 1 issues steering control signals from the output ports P ₁₄ and P ₁₅ to realize this steering angle. The electronic circuit connected to these output ports P ₁₄ and P ₁₅ is the solenoid valve 2 in the hydraulic circuit for steering drive shown in Fig. 8.
This is a drive circuit for controlling the energization of the solenoids 2ls, 2rs, and 2cs of the solenoids 2ls, 2rs, and 2c, respectively, and includes two PNP transistors 22l, Darlington-connected to the comparators 21l, 21r, respectively.
It consists of 23l, 22r, 23r, etc. Output port P ₁₄ (or P ₁₅ ) is at a high level when the determined steering angle is 0, and when the steering angle is +θ ₂ , +θ ₁
(or -θ ₂ , -θ ₁ ), it becomes a low level. The steering control signal emitted from this output port P ₁₄ (or P ₁₅ ) is applied to the + input terminal of the comparator 21l (or 21r), and the high/low level of the output port is output from the output terminal. A signal corresponding to will be emitted. This signal is input to the base of one of the Darlington-connected transistors 22l (or 22r). While the signal is at high level, the transistor 22l (or 22r) is off, but when it changes to low level, it is turned on, and accordingly, the other transistor 23l (or 23r) is turned off.
will also turn on. In this way, the emitter of the transistor 23l (or 23r), which is turned on when the output port P ₁₄ (or P ₁₅ ) becomes low level, is at a positive potential +Vcc, and the collector is grounded to the body via the solenoid 2ls (or 2rs). ing. On the other hand, one end of the solenoid 2cs is grounded to the body, and the other end is connected to the cathodes of diodes 24 and 25 and the anode of a diode 26. The anodes of the diodes 24 and 25 are connected to the collectors of the transistors 23l and 23r, respectively,
Further, the cathode of the diode 26 is connected to the +Vcc line. Another diode 2
The cathode of transistor 7 is connected to the +Vcc line, and the anode is connected to the collector of transistor 23l. Therefore, when the transistor 23l (or 23r) is turned on, both the solenoids 2ls and 2cs (or 2rs and 2cs) are energized. Next, the hydraulic circuit shown in FIG. 8 will be explained. 30
is a variable displacement hydraulic pump, and has a solenoid valve 2c.
and the left and right prologue 3 through 2l and 2r respectively.
Hydraulic motor 31l mounted directly on each of 2l and 32r
and 31r, and to the hydraulic motors 31'l and 31'r directly mounted on the left and right rear wheels 32'l and 32'r via the solenoid valve 2c to rotate them. Depending on the left front and rear wheels 32l, 32'
A hydraulic pump 3 is adapted to drive the right front and rear wheels 32r and 32'r, and whose oil flow direction and pressure oil supply amount are linked to a speed change lever 112 (see Fig. 1).
Adjustments are made using the movable swash plate 0, which allows selection of forward and backward movement and adjustment of traveling speed. The solenoid valve 2c is a 3-port, 2-position switching type directional control valve, and when the solenoid 2cs is demagnetized, it is in the position shown in the figure, and is connected to the hydraulic motor 31l side and the planting part 1.
Pressure oil is supplied to the electromagnetic valve 2d for lifting and lowering control of 03. On the other hand, when the solenoid 2cs is energized, the supply of pressure oil to the electromagnetic valve 2d side is cut off, and the pressure oil is supplied to the hydraulic motor 31l, etc. side.
The solenoid valve 2d is a 3-port, 3-position switching type directional control valve, and when the solenoids 2ds ₁ and 2ds ₂ are demagnetized, it is in the position shown in the figure to seal off the pressure oil from the hydraulic pump 30 and to close off the pressure oil from the single-acting hydraulic cylinder 34. The oil chamber is sealed and the planted portion 103 connected to the piston rod of the hydraulic cylinder 34 is held at the current position.
On the other hand, when the solenoid 2ds ₁ is energized, the position is switched in the direction of the arrow, supplying pressure oil to the hydraulic cylinder 34, advancing the piston rod, and rotating the lift arm 106 upward to raise the planting section 103. let On the other hand, when the other solenoid _2ds2 is energized, the position is switched in the direction opposite to the arrow mark, so that the pressure oil in the oil chamber of the hydraulic cylinder 34 can be returned to the tank. As a result, the planting section 103 descends due to its own weight. On the other hand, the solenoid valve 2l (or 2r) is a two-position switching type stop valve, and when the solenoid 2ls (or 2rs) is demagnetized, the solenoid valve 2l (or 2r) is in the position shown, and the pressure oil is supplied to the hydraulic motor 31l (or 31r). and rotate it. On the other hand, solenoid 2LS
(or 2rs) is excited, the position is switched, the supply of pressure oil to the hydraulic motor 31l (or 31r) is cut off, and its rotational drive is stopped and braking is applied. Therefore, when solenoid 2ls (or 2rs) is energized, the left (or right) front wheel 3
2l (or 32r) will stop rotating and the aircraft will turn to the left (or right), but as mentioned above, when solenoid 2ls (or 2rs) is energized, solenoid 2cs is also energized. Therefore, the supply of pressure oil to the hydraulic system for raising and lowering the planting section 103, that is, the solenoid valve 2d side, is cut off, so all the pressure oil is supplied to the hydraulic motor 31r, etc. (or 31l, etc.) side, and its rotation speed is controlled. As a result, a powerful turn to the left (or right) is made. Note that while such steering is performed, pressure oil is not supplied to the hydraulic cylinder 34, so if the planting section 103 is being driven upward, the upward movement is temporarily stopped.
While automatic steering is in progress, planting is in progress.
Since there is no need to drive the planting section 103 upward, there is virtually no problem. Others 35 are pressure relief valves, 3
6 is a charge pump. Now, returning to FIG. 7 again, comparators 21l, 21
Switches 28l and 28r are interposed between the output terminals of r and the body ground, respectively. The switch 28l (or 28r) is arranged so as to close the circuit when the steering wheel 101 is rotated to the left (or right) by an appropriate amount, and the output of the comparator 21l (or 21r) is With the terminal set to low level, transistors 22l, 23l (or 22
r, 23r) is turned on, thereby energizing the solenoid 2ls (or 2rs), allowing manual steering operation. In this way, manual steering can be accomplished by simply closing the switches 28l and 28r, so the switches 28l and 28r may be provided as push button switches on the operating column 111 without providing the steering wheel 101. Now, 41 is a steering sensor for detecting the actual steering angle of this rice transplanter. In other words, the body of this rice transplanter is a foldable type, and the angle of horizontal rotation of the front body F with respect to the rear body R during turning is determined at the pivot joint 113 between the front body F and the rear body R. As you can see, it is composed of a potentiometer that changes the output voltage according to the amount of horizontal rotation of the front body F. The output voltage of this steering sensor 41 is a V/F formed by a timer IC (type 555).
The signal is input to a (voltage/frequency) converter 42, and the signal subjected to V/F conversion is input to the input port _T1 of the data processing device. This input signal causes the data processing device 1 to output ports P ₁₄ ,
The actual steering condition can be detected by the steering control signal from _P15 . Then, the data of the steering angles ±θ ₁ and ±θ ₂ determined as described above and stored in appropriate registers and the actual steering angle inputted from the steering sensor 41 via the V/F converter 42 are used. When the data of the angle of entry match, the outputs of the output ports P ₁₄ and P ₁₅ are returned to high level, and the straight traveling state is restored. Note that the signal AUTO inputted to the data processing device 1 by an appropriately provided switch is a signal for instructing the operation of this transplanter in automatic mode, and is a signal for instructing the operation of the transplanter in automatic mode _.
A predetermined initial operation is performed, including the lowering of the planting section 103 by energization, and then the automatic steering as described above is performed. As detailed above, according to the present invention, the presence of the seedlings is detected by the touch rod of the seedling sensor coming into contact with the planted seedlings, thereby recognizing the relative positional relationship between the machine body and the planted seedlings. In addition, in the seedling sensor of the present invention, the input terminal of the comparator whose output is the detection of contact with seedlings is connected to the reference voltage terminal. Since the bias is applied to a slightly different voltage using a resistor with a high resistance value, the presence of already planted seedlings with a high resistance can be reliably detected and there is no possibility of misdirection. In addition, when using an optical sensor or when using a method of providing a special guide means as described above in place of the already planted seedling row, it becomes extremely expensive, but in the case of the present invention, since the seedling sensor is inexpensive, it can be automated at low cost. It has the advantage of being able to provide a steering device. Since the touch rod of the seedling sensor extends in the traveling direction of the aircraft, a certain amount of time is secured for the seedling sensor to come into contact with the seedling while the vehicle is traveling, so that a signal caused by the contact can be reliably captured. Furthermore, since a plurality of touch rods are provided in a direction perpendicular to the running direction, even if seedlings are scattered in this direction, automatic steering can be performed without the touch rods losing sight of the seedlings. Since the amount of steering is determined by the pattern of the comparator output,
In the embodiment described above, there were two types of steering on one side, but it is possible to determine more various steering amounts. This allows for more precise control such as determining the amount of steering. Furthermore, as described above, hunting can be prevented by setting the steering amount to 0 for certain patterns and prohibiting unnecessary steering. In the above embodiment, four seedling sensors are provided on each of the left and right sides, but the number is not limited to four.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, in which Figure 1 is a left side view of a rice transplanter equipped with the device of the present invention, Figure 2 is a perspective view of a group of touch rods, and Figures 3 to 6. The figure is a circuit diagram of the seedling sensor, FIG. 7 is a block diagram schematically showing the main parts of the electronic circuit of the apparatus of the present invention, and FIG. 8 is a circuit diagram schematically showing the main parts of the hydraulic system. 11... Comparator, 14... Bias resistor, 81-8
4... touch rod, 81l-84l, 81r-84r... seedling sensor.

Claims (1)

[Claims] 1 Understanding the relative positional relationship between the already planted seedlings and the aircraft,
In an automatic steering device for a transplanter that is configured to run in a manner that follows the rows of already planted seedlings, a plurality of transplanters are installed in the direction perpendicular to the direction of travel of the machine so as to extend in the direction of travel of the machine and come into contact with the already planted seedlings. The input terminal of each comparator is connected directly or indirectly to each touch stick, and the input terminal of each comparator is connected directly or indirectly to each touch stick. Using a resistor, the comparator output is biased to a potential slightly different from the reference voltage terminal, and when the touch rod comes into contact with a planted seedling, the comparator output is inverted. An automatic steering device for a transplanted machine, comprising a data processing device that takes an output as an input and determines a steering amount by recognizing the relative positional relationship based on a data pattern consisting of the outputs of a plurality of comparators.