JPH0125521B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an automatic steering device installed in a transplanting machine such as a rice transplanter, and proposes an automatic steering device that improves operability at the start of automatic steering. The present invention will be specifically described below based on drawings showing embodiments thereof. Fig. 1 is a left side view of a riding rice transplanter equipped with an automatic steering device according to the present invention (hereinafter referred to as the device of the present invention). It has a body-folding structure that horizontally rotates around a connecting shaft, and is configured to be manually steered by rotating the steering wheel 101, or automatically steered by the device of the present invention. That is, as shown in FIG. 3, the steering mechanism includes a steering rod 1 interposed between a pitman arm 102 and a rear fuselage R, which are rotated back and forth by the rotation of a steering wheel 101.
02' consists of a double-acting hydraulic cylinder 92, which transmits the operation of the steering wheel 101 to the rear fuselage R by prohibiting the supply and discharge of pressure oil during manual steering, and also uses a solenoid valve during automatic steering. 91 solenoid 91l or 91
By energizing r, the flow rate of pressure oil in a hydraulic circuit (not shown) is switched, the hydraulic cylinder 92 is operated, and the rear body R is rotated with respect to the front body F.
The vehicle is configured to be steered to the left or right. Seedling sensors are attached to the left and right sides of the bumper 103' of the planting section 103. That is, as shown in FIG. 2 for the left seedling sensor, the bumper 10
A sensor box 1 is installed at the tip of a pipe arm 107 extending outward from the left side of the fuselage.
08 is installed, and this sensor box 1
From the bottom of 08, there are four touch rods 81, 8 of the seedling sensor.
2, 83, and 84 are arranged in a protruding manner. The touch rods 81 to 84 are made of thin conductors, and extend downward from the sensor box 108, then extend obliquely forward and downward, and then bent backward, so that this portion is substantially horizontal. This horizontal part is sufficiently longer than the distance between plants of the Z row of already planted seedlings, which is about 150 mm in the direction of machine movement.
Specifically, it is approximately 250mm. And the touch rod 81
-84 are arranged in parallel from left to right in the order of 81, 82, 83, and 84 at a distance of about 50 mm from each other in the left-right direction of the fuselage. And the four tentacles81~
The group of contact rods 84 is arranged so that it can contact the upper part of the seedlings constituting the row of planted seedlings closest to the aircraft among the group of already planted seedlings when the planting section 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. FIG. 3 is a circuit diagram showing the main part of the electronic circuit of the device of the present invention with respect to the seedling sensor on the left side.
2, 83, and 84 are connected to the + input terminals of the comparators 12, 11, 14, and 13 through a shield wire 87 connected to a connector 108h arranged outside the sensor box 108, and through a resistor (about 100 kΩ). has been done. The negative input terminals of the comparators 11 to 14 are configured to receive a reference potential output from the terminal of a window comparator 20, which will be described later. And between the ± terminals of each comparator 11 to 14 is a variable resistor 40 and 1MΩ for bias potential setting.
When a bias potential is applied using a relatively high resistance 42 or the like and the touch rod is not in contact with the seedling Z, the potential of the + input terminal is made slightly higher than the potential of the - input terminal. Therefore, when the touch rod is not in contact with the seedling Z, the output of the comparator 11 etc. is at a high level, but when the touch rod is in contact with the seedling Z, the output is Since it is grounded, the + input terminal has a lower potential than the - input terminal, and the output of each comparator 11 etc. changes to low level. 22 is a comparator, the negative terminal of which is connected to the anodes of diodes 23, 24, 25, and 26 whose cathodes are connected to the respective output terminals of the comparators 11 to 14, and is also used for setting a time constant. It is connected to the positive power supply line of the battery 32 via a variable resistor 27, and is grounded via a capacitor 28. The terminal of the window comparator 20 is connected to a variable resistor 40, 4 for setting a bias voltage.
1, and this variable resistor 41
The + terminal of the comparator 22 is connected to the intermediate terminal of the comparator 22. 29 is also a comparator, and its negative terminal is connected to the intermediate terminal of the variable resistor 41, and its positive terminal connects the anodes of the diodes whose cathodes are connected to the positive terminals of the comparators 11 to 14 as described above. It is also connected to the terminal via a high resistance 42. Further, a diode whose anode side is connected to the - terminal is interposed between the ± terminals. The output terminals of the comparators 22 and 29 are collectively connected to a connection point between a buzzer 38 and diodes 43 and 44 whose anodes are connected to a terminal of the window comparator 20, which will be described later. By making such a connection, the comparators 11 to 1
If a predetermined time elapses with any of the outputs of 4 being at a high level, that is, a state in which the sensor does not detect any seedlings, a predetermined time constant based on the resistance value set by the variable resistor 27 and the capacitance of the capacitor 28 is determined. If it continues for a long time, the output of the comparator 22 becomes low level, and if the seedling sensor is grounded with a resistance value significantly lower than the surface resistance of the seedling, specifically, due to straw leaking into the water, etc. If it is grounded, the output of the comparator 29 becomes low level, and in any of these cases, the terminal of the window comparator 20,
becomes the ground level, and the window comparator 20
output operation is prohibited, the operation of the automatic steering system is stopped, and the buzzer 38 sounds to issue an alarm. Voltage divider 17 is 5kΩ resistor 171, both are 10k
Resistance 172, 173, 174, 175 and 5 Ω
Ω resistors 176 are connected in series, one end of which is given the reference potential output by the window comparator 20, and the other end grounded to the body. Reference numerals 15 and 16 are switch transistors which apply the respective outputs of comparators 11 and 12 to their respective bases, and turn on when these outputs become low level to connect the connection point P ₁ between resistors 171 and 172 and the resistor 172. The connection point _P2 between and 173 is the emitter side potential,
That is, it is connected to have the same potential as the reference potential of the window comparator 20. Further, the output terminals of the comparators 13 and 14 are connected to the connection point between the resistors 174 and 175 and the connection points P ₄ and P ₅ between the resistors 175 and 176, respectively. The window comparator 20 is a semiconductor device that discriminates a changing input voltage by comparing it with two freely settable comparison reference voltages, and in this embodiment, TCA965 manufactured by Siemens is used. In the figure, it is a power terminal and is connected to the positive terminal of a battery 32 via an automatic steering selection switch 31 which is to be closed when commanding automatic steering. The terminal of the window comparator 20 is a terminal that emits a constant voltage of 6.4V with respect to the ground terminal as the reference potential when a predetermined voltage is applied to the power supply terminal.
14 and one end of the voltage divider 17, and also connected to one end of the steering sensor 33. This steering sensor 33 consists of a potentiometer connected in conjunction with the rod of the hydraulic cylinder 92, and the other end is grounded via a resistor. The output voltage V ₃₃ of the steering sensor ₃₃ changes depending on the forward and backward positions of the rod of the hydraulic cylinder 92, and becomes a signal representing the steering angle. It is designed to be given to Note that the steering sensor 33 outputs V ₃₃ =3.2V (=6.4/
2V). Also, when steering to the left, V ₃₃ rises, and conversely, when steering to the right,
It is interlocked and connected to the hydraulic cylinder rod so that V ₃₃ is lowered. As shown in FIG. 4, the terminal of the window comparator 20 is an input terminal to which a voltage defining the midpoint of the window should be applied, and is connected to the connection point _P3 between the resistors 173 and 174 in the voltage divider 17. That voltage V ₃ is applied to the terminal. The aforementioned terminal is also connected to a fixed resistor 181 of 10kΩ.
It is grounded through a series circuit with a 1 kΩ variable resistor 182, and the intermediate terminal potential of the variable resistor 182 is applied to the terminal of the window comparator 20.
The input voltage V ₉ to the terminal defines the 1/2 width of the window as shown in FIG. Terminal is a terminal that inhibits the output operation of the window comparator 20 when it is set to a level close to the ground potential, and is connected to the connection point P between the buzzer 38 and the output terminals of the comparators 22 and 29 via diodes 43 and 44. It is connected to the. The terminals are the output terminals of the window comparator 20, and are connected to the drive circuits 19r and 19l each formed by connecting two transistors in Darlington connection, and when the respective outputs become low level, the solenoids 91r and 91l are excited. It is designed to do so. A closed circuit of the switch 31 is indicated by lighting between the positive electrode line which is opened and closed by the switch 31 and the body ground. A series circuit of an automatic selection lamp 35, a normally open limit switch contact 36, and a straight ahead indicator lamp 37 are connected in parallel. This limit switch is placed so as to face the rotation of the pitman arm 102, and its normally open contact 36 closes in a narrow rotation angle range (about 1 degree) of the pitman arm when the aircraft is traveling approximately straight. However, the fact that the aircraft is traveling substantially straight is reported by lighting the straight ahead indicator lamp 37. Further, a series circuit including a limit switch contact 34 and a buzzer 38 is connected between the positive electrode line and the connection point P. The above limit switch is the steering wheel 101
The contact point 34 closes when the seedling is moved forward as in the case of seedling succession. The feature of the device of the present invention is that the steering mechanism is forcibly operated for a predetermined period of time immediately after the automatic steering selection switch 31 is closed and power supply to the automatic steering device is started. , the aircraft is made to go straight ahead, and then the window comparator 20 is disabled. To realize this, a capacitor 45 is placed between the positive electrode line and the connection point P, and a resistor 46 is placed between the connection point P.
and ground potential. Next, the operation of the window comparator 20 will be briefly explained based on FIG. Figure 4 A and B are terminals, respectively, and the binary output V ₂ ,
V ₃₃ is plotted on the horizontal axis with V ₁₄ . _V14
is low level when V ₃₃ < V ₃ − V ₉ , and high level when V ₃₃ > V ₃ − V ₉ , and V ₂ is high level when V ₃₃ < V ₃ + V ₉ , and low when V ₃₃ > V ₃ + V ₉ . level. The range from V ₃ −V ₉ to _{V 3} +V ₉ is called the window, and V ₃
defines the midpoint and V ₉ defines 1/2 of its width. In the device of the present invention, _V9 , which defines the 1/2 width, is fixed at an appropriately set value by the variable resistor 182.
V ₃ changes depending on the contact state between the touch rods 81 to 84 and the planted seedlings Z, and V ₃₃ also changes depending on the steering state. In other words, depending on the relative positional relationship between the planted seedlings and the aircraft and the steering condition, V ₂ or V ₁₄ becomes low level and solenoid 91r or 91l is energized, resulting in steering to the right or left. Become. And if V ₃₃ is within the window, i.e. V ₃ −V ₉ ~
If it is in the range of V ₃ + V ₉ , steering is not performed as a dead zone for steering control. The window midpoint, ie, _V3 , has a meaning as information representing the relative position of the planted seedlings and the machine body, and this will be explained below. Table 1 lists the relationship between the presence or absence of seedlings in contact with the tentacles 81 to 84 and _V3 , where 0 indicates no contact and 1 indicates contact. Also, looking at the outputs of the comparators 12, 11, 14, and 13 connected to each of the touch rods 81, 82, 83, and 84, 0 in the table is a high level, and 1 in the table is a low level. Each corresponds.

[Table] In this way, only 7 voltages can be obtained for 16 different contact situations for the 4 touch rods, but if the distance between each touch rod and other dimensional conditions are set as described above. By keeping the seedlings in place, except in special cases, the seedlings will not come into contact with any of the rods, will come into contact with any one rod, or will come into contact with two adjacent rods.
Since there are only two situations, there will actually be eight situations in columns 1 to 5 and 7, 9, and 13 marked with an asterisk.
V ₃ is 5 of 4.75V, 3.56V, 3.2V, 2.84V and 1.83V
However, it is not necessary to identify the situation in column 9 and the situation in column 13 (both 4.75V) or the situation in column 2 and the situation in column 4 (both 1.83V) for steering control. In addition, when the seedling is between the touch rods 82 and 83, the situation in column 1 and the situation in column 7 are equivalent situations in which steering is ideally performed, and there is no need for identification. V ₃ is 3.2V, which is the ideal running condition, and if it is higher than this, the aircraft is moving away from the planted seedling row (looking at the sensor on the left, it is shifting to the right from the planted seedling row). The larger the difference, the greater the deviation, and
If it is smaller than 3.2V, the aircraft is too close to the row of planted seedlings, and the smaller the voltage, the greater the deviation. In this way, V ₃ includes information indicating the aircraft position, but
In the case of column 1 where V ₃ = 3.2V, the seedlings are attached to the touch rods 81 to 8.
This may include a state between 2 or 83 and 84, or a state outside the touch rod 81 or inside 84. However, as will be described later, as long as the switch to automatic steering is performed while the aircraft is traveling straight and seedlings are detected by the seedling sensor, the latter two situations will occur. There is no possibility, and in the case of the first two cases, a state in which one of the touch rods comes into contact with the seedling occurs after a while, so there is no possibility that the steering becomes uncontrollable. The device of the present invention having such a configuration is used and operates as follows. That is, automatic steering becomes possible after one or more rows of planting are completed and a row of already planted seedlings is formed. In order to perform automatic steering that follows this row of already planted seedlings,
An operation for turning the aircraft is performed by manual steering, and the automatic steering selection switch 31 is closed around the time this turning is completed. Then automatic selection lamp 3
5 lights up and power is supplied to the terminal of the window comparator 20, while at the moment the switch 31 is closed, the connection point P is raised to a potential approximately equal to the voltage of the battery 32 via the capacitor 45. However, since the aircraft is in the middle of a round trip, none of the touch rods 81 to 84 are in contact with Nae Z, and the first
Assuming that the conditions shown in Table 1 are present, _V3 is 3.2V, and the aircraft is in ideal running conditions, solenoid 9 is
1l (or 91r) is excited, and the hydraulic cylinder 9
2 to turn the steering mechanism into a straight-ahead state. The potential at the connection point P falls according to a time constant determined by the capacitance of the capacitor 45 and the resistance value of the resistor 46, and when it reaches a predetermined level close to the ground potential, the operation of the window comparator 20 is prohibited. In this state, the touch rods 81 to 84 come into contact with the seedling Z, and the planting part 10
If the steering wheel 101 is in a state where it can be contacted by lowering the steering wheel 101, the steering wheel 101 is moved forward. In addition, if the seedling Z and the touch rods 81 to 84 are separated from each other, the steering wheel 101 is operated to align the two under a state in which automatic steering is prohibited, and the steering mechanism is set to the straight-ahead state. to move the steering wheel 101 forward. Note that the fact that the steering mechanism has entered the straight-ahead state is reported by the lighting of the straight-ahead indicator lamp 37. When the steered wheels 101 are moved forward as described above, the potential at the connection point P becomes an appropriate level determined by the impedance of the buzzer 38 and the resistance value of the resistor 46, so that the operation of the window comparator 20 is inhibited. It will be released and automatic steering will begin. As described above, the automatic steering device for a transplanter according to the present invention grasps the relative positional relationship between the already planted seedlings and the machine body, and causes the automatic steering device for the transplanter to run following the row of already planted seedlings. In this case, the steering mechanism is configured to be set in a straight line state by operating a switch that commands automatic steering, so switching from manual steering to automatic steering can be easily and smoothly performed. This has an excellent effect on improving operability.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, in which Fig. 1 is a left side view of a riding rice transplanter equipped with the device of the present invention, Fig. 2 is an external view of a seedling sensor, and Fig. 3 is a diagram of the device of the present invention. FIG. 4 is a circuit diagram showing the main parts of the electronic circuit, and is an explanatory diagram of the operation of the window comparator. 11, 12, 13, 14, 22, 29... Comparator, 17... Voltage divider, 20... Window comparator, 23, 24, 25, 26, 43, 44...
Diode, 27, 40, 41...variable resistor,
28, 45... Capacitor, 33... Steering sensor, 46... Resistor, 81, 82, 83, 84...
touch rod.

Claims (1)

[Claims] 1 Understanding the relative positional relationship between the already planted seedlings and the aircraft,
An automatic steering device for a transplanting machine configured to travel along a row of already planted seedlings, characterized in that the steering mechanism is configured to set the steering mechanism to a straight-line state by operating a switch that commands automatic steering. Automatic steering device of the aircraft.