JPH0126641B2 - - 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 in particular, it controls by simplifying an electronic circuit for capturing the relative positional relationship between the planted seedlings and the machine body, which is basic information for steering control. This proposed an automatic steering system with improved accuracy and reliability. 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, and the steering is performed by horizontally rotating the front body F and the rear body R about their connecting axis. It has a bendable body structure, and is configured to perform manual steering by rotating the steering wheel 101 or automatic steering by the device of the present invention. Automatic steering is performed using the solenoid valve 91 shown in Figure 3.
By energizing the solenoid 91l or 91r, the pressure oil flow path of the hydraulic circuit (not shown) is switched to operate the double-acting hydraulic cylinder 92, and the Pitman arm 102 connected to the rod is rotated back and forth and connected thereto. Rotate the rear body R with respect to the front body F at the drag rod 102',
The vehicle is configured to be steered to the left or right. Four seedling sensors are attached to the left and right sides of the bumper 103' of the planting section 103, respectively. Specifically, as shown in FIG. 2 for the left seedling sensor, a sensor box 108 is attached to the tip of a pipe arm 107 that extends outward from the left side of the bumper 103'. From the box are the four touch rods of the seedling sensor 81, 8.
2, 83, and 84 are arranged in a protruding manner. The touch rods 81 to 84 are made of thin conductors, the front and rear ends are bent upward, and the straight part in the middle is sufficiently longer than the distance between plants in the direction of movement of the machine in the Z row of already planted seedlings, which is approximately 150 mm, specifically, The front end is fixed within the sensor box 108, and the shield wire 93 (third
(see figure) to the electronic circuit inside the operation column 111. 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 distance, horizontal rods 109 and 109 made of electrical insulators are installed at the front bent part and the rear bent part of the straight part. The sensor box 10 is fixed in a suitable manner and further includes a rear end located above and a sensor box 10.
It is supported by an insulating plate 109' which is placed astride between 8 and 8, and has a sled-like structure as a whole. The group of four contact rods 81 to 84 forms the row of planted seedlings that is closest to the aircraft among the group of planted seedlings when the planting section 103 is lowered and its float 110 lands on the water. Arm 107 so as to be able to contact the upper part of the seedling.
The length of the handle and the length of the handle 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 93 passed through a pipe 107, etc., and via a resistor (approximately 100 kΩ). The negative input terminals of the comparators 11 to 14 are configured to receive a reference potential output from a window comparator 20, which will be described later. A parallel circuit consisting of a high resistance of about 1 MΩ and two anti-parallel diodes is interposed between the ± terminals of each comparator 11 to 14, so that when the touch rod is not in contact with the seedling Z, the + The potential of the input terminal is biased to be 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. The voltage divider 17 is a 5kΩ resistor 171, both
10 kΩ resistors 172, 173, 174, 175 and 5 kΩ resistor 176 are connected in series,
The reference potential output by the window comparator 20 is applied to one end, and the other end is 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 when these outputs become low level, turn on and connect the connection point _P1 between resistors 171 and 172 and the resistor. The connection point P ₂ between 172 and 173 is connected so as to have an emitter side potential, that is, the potential equal to the reference potential of the window comparator 20. Further, the output terminals of comparators 13 and 14 are connected to resistors 17 and 17, respectively.
4 and 175, and to connection points _P4 and _P5 between 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 a switch 31 which is to be closed when automatic steering is selected. Terminal ^J of the window comparator 20 becomes 6.4V with respect to the ground terminal when a predetermined voltage is applied to the power supply terminal.
This is a terminal that emits a constant voltage as the above-mentioned reference potential, and is connected to the - terminal of the comparators 11 to 14 and the - end of the voltage divider 17 as described above, as well as the - end of the steering sensor 33. has been done. 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. Output voltage of steering sensor 33
V 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, and the output voltage V ₃₃ is applied to the terminal as a signal to be compared and identified. Note that the steering sensor 33 has a steering angle of 0 degrees (the state in which the aircraft is traveling straight).
It is set so that V ₃₃ =3.2V (=6.4/2V) in a certain case. Also, if you steer to the left, V ₃₃
It is linked to the hydraulic cylinder rod so that _V33 rises and, conversely, when the steering is turned to the right, V33 falls. 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. The potential 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 2 is a terminal that inhibits the output of the window comparator 20 when set to ground potential, and is connected to body ground via a diode and a normally closed limit switch contact 34. This limit switch is arranged near the steering wheel 101, and the contact point 34 is opened when the limit switch is moved forward as in the case of seedling succession. The terminals are output terminals of the window comparator 20, and are connected to drive circuits 19r and 19l, each consisting of two transistors connected in Darlington, and excite the solenoids 91r and 91l when their respective outputs become low level. It is designed to do so. Between the positive electrode line which is opened and closed by the switch 31 and the body ground, there is connected in parallel a series circuit consisting of an automatic selection lamp 35, which indicates the closing of the switch 31 by its lighting, a normally open limit switch contact 36, and a straight ahead indicator lamp 37. It is connected. This limit switch is placed facing the rotation range 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. The limit switch contact 34 and the connection point of the diode, the lamp 37 and the limit switch contact 36
A series circuit of a diode and a buzzer 38 is connected between the two. 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 between the planted seedlings and the aircraft 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 2.84V) 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 both equivalent situations in which steering is done in a modern manner, so there is no need for identification. In short, V ₃ is 3.2V, which is the ideal running situation, and if it is higher than this, the aircraft is moving away from the row of planted seedlings (looking at the sensor on the left, it is shifting to the right from the row of planted seedlings). , the larger the difference, the larger 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 conditions 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. If the row of planted seedlings is currently on the left side of the aircraft, turn the steering wheel 10 to bring the left seedling sensor into contact with the row of planted seedlings.
1, while the automatic steering selection switch 31 is closed. Under these circumstances, when the aircraft is able to move straight, the limit switch contact 36 closes, lighting the straight-ahead indicator lamp 37 and making the buzzer 38 sound. The driver now knows that it is now possible to switch to automatic steering, and more precisely, the aircraft is now in a state where it can safely switch to automatic steering without the aircraft traveling in an unexpected direction. At this point, the steering wheel 101 is moved forward. Then, the limit switch contact 34 opens and the buzzer 8 stops sounding, while
The prohibition of the operation of the window comparator 20 is lifted. Then, for some reason, the aircraft moves to the right (or left).
Assuming that the seedling is in the state shown in column 5 (or column 3) of Table 1, where the seedling is in contact with the left (or right) touch rod 82 or 83, _V3 will be 3.56V (or 2.84V). Therefore, the window will move to the high (or low) voltage side. Since the output voltage V ₃₃ of the steering sensor 33 is switched from the state where the contact 36 is closed to automatic steering,
Since it is at 3.2V (straight ahead) or a value close to this, _V14 or _V2 becomes low level as the window moves to the high voltage side (or low voltage side) and solenoid 91
As a result of energizing l or 91r, the aircraft corrects its direction of travel to the left (or right), resulting in 1 or 7 in Table 1.
Return to column state. This operation is the same in the case of Column 9 (or Column 2) of Table 1, where the seedling comes into contact with the touch rod 81 or 84, but in these cases, the amount of movement of the window toward the high (or low) pressure side is Even if the output of the steering sensor 33 was slightly higher (or lower) than 3.2V, it would still be possible to correct the direction to the left (or right). Even if V ₁₄ or V ₂ becomes a low level, the solenoid 91l or 91r is energized and the hydraulic cylinder 92 is operated to increase the amount of steering to the left (or right) and quickly move to column 1 or 7. The operation will be performed to return the vehicle to its straight-ahead state. As described above, the automatic steering device for a transplanter according to the present invention uses a signal from a sensor provided to detect the relative positional relationship between the planted seedlings and the machine body as a window position determination signal, and also captures the steering angle. The signal from the sensor provided for this purpose is input to the window comparator as a window width determination signal, and the steering control is performed according to the discrimination result of the window comparator. There is no need to provide a circuit to obtain the average level of signals from multiple sensors, and there is no need to provide a microprocessor for logical judgment or steering control, simplifying the circuit and making adjustment and maintenance easier. Not only is this possible, but it is also more reliable and can be manufactured at a lower cost. Furthermore, control accuracy is high because adjustment is extremely simple, and factors that cause malfunctions can be eliminated due to circuit simplification. If the deviation from the already planted seedlings is small, the amount of movement of the window position, that is, the midpoint, is small, making it difficult to steer, and hunting can therefore be prevented.
On the other hand, the greater the deviation from the already planted seedling row, the greater the amount of movement of the window position of the window comparator to ensure reliable steering, resulting in excellent responsiveness. It has a great effect.

[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... Comparator, 17... Voltage divider, 20... Window comparator, 33... Steering sensor, 81, 82, 83, 84... Touch rod.

Claims (1)

[Claims] 1 The signal from the sensor installed to determine the relative positional relationship between the planted seedlings and the aircraft body is used as the window position determination signal, and the signal from the sensor installed to determine the steering angle is used as the window width determination signal. 1. An automatic steering device for a transplant machine, characterized in that an input is input to a comparator and steering control is performed in accordance with the discrimination result of the window comparator.