JPH023683Y2 - - 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. More specifically, the present invention relates to an automatic steering device that is installed in a transplanting machine such as a rice transplanter. The present invention proposes an automatic steering system for a transplanted machine that improves the accuracy of automatic steering by detecting the actual conditions, and also has a simple structure that improves economic efficiency 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 (hereinafter referred to as the proposed device), and Fig. 2 is an electronic circuit diagram of its main parts. Part fuselage F and rear fuselage R
The steering wheel 101 has a bent-body structure that horizontally rotates the steering wheel 101 about its connecting axis, and the steering can be performed manually by rotating the steering wheel 101 or automatically by the device of the present invention. That is, as shown in FIG. 2, a part of the drag rod 102' interposed between the rear fuselage R and the pitman arm 102, which is rotated back and forth by the rotation of the steering wheel 101, is connected to a double-acting hydraulic cylinder 92. During manual steering, the supply and discharge of pressure oil is prohibited and the operation of the steering wheel 101 is controlled from the rear fuselage R.
and by energizing the solenoid 91l or 91r of the solenoid valve 91 during automatic steering.
The pressure oil flow path of the hydraulic circuit (not shown) is switched and the hydraulic cylinder 92 is operated to convert the rear fuselage R to the front fuselage F.
The steering wheel is configured to be rotated relative to the steering wheel to perform steering to the left or right.

Steering sensors 30l and 30r are attached to the left and right sides of the bumper 103' of the planting section 103, respectively. Left and right steering sensors 30l, 30r
have the same structure, one steering sensor 30l
Or 30r uses two light emitting diodes 38l or 38r, 39l or 39r and one photodiode 40l or 40r as a light emitting and receiving element, respectively, and two light emitting diodes 38l or 38r,
39l or 39r are arranged on the upper left and right respectively, and both light emitting diodes 38l or 38r, 39l or 3
Photodiode 40l or 4 below the center of 9r
0r, each light emitting and receiving surface facing the front of the aircraft, and both light emitting diodes 38l or 38r, 39l.
Alternatively, one converging lens is located in front of photodiode 39r, and one converging lens is located in front of photodiode 40l or 40r. and each light emitting diode 38l or 38r, 39l or 39r
The projected light emitted from the seedlings is reflected by the seedlings Z constituting the row of planted seedlings closest to the aircraft body, and the reflected light is captured by a photodiode 40l or 40r. Figure 3 shows each light emitting diode 38l or 3
8r, 39l or 39r, and FIG. 4 is a plan view showing the light receiving area of photodiode 40l or 40r, respectively.
The light emitting area a of 8l or 38r is on the right side from the center front of both light emitting diodes 38l or 38r, 39l or 39r, and on the contrary, the light emitting area b of the right light emitting diode 39l or 39r is on the left side. There is. Also photodiode 40L or 4
The light receiving area c of 0r is the photodiode 40l.
Or they are evenly spaced on the left and right sides of the front of 40r.

The sensor box 301l or 301r of the steering sensor 30l or 30r projects light onto the upper end of the mounting rod 302l or 302r installed on the left (or right) side of the bumper 103'.
The light emitting/receiving surface is tilted forward so as to reliably detect the reflected light after it is reflected by the already planted seedlings Z located about 1.5 m in front of the light. Also, each mounting rod 30 on the left and right side of the bumper 103'
Side markers 8l and 8r, which serve as steering targets during alignment, are protruded forward slightly on the inside of the fuselage from 2l and 302r.

Now, as shown in Fig. 2, a key switch 3 is connected to the positive terminal of the battery 31, one end of which is grounded to the body.
A pulse oscillator 33 is connected via 2,
As shown in Figure 5A, a pulse with a duty ratio of 1/2 is output. The output of the pulse oscillator 33 is J-
It is connected to the trigger input terminal _T1 of the K flip-flop 34. The J-K flip-flop 34
connects the J ₁ and K ₁ terminals as well as the clear terminal C ₁ , which is reset when the power is turned on, to the battery 3.
1 positive line, and its Q ₁ output terminal to J
−K flip-flop 35 trigger input terminal T ₂
and connect the Q ₁ output terminal to NOR gates 36 and 37.
are connected to each input terminal. The J2 and _K2 terminals of the J-K flip-flop 35 and the clear terminal _C2 , which is reset when the power is turned on, are also connected to the _J2 terminal.
-Battery 31 as well as K flip-flop 34
The Q ₂ output terminal is connected to the positive terminal of the NOR
The input terminal of the gate 36 and the _Q2 output terminal are connected to the input terminal of the NOR gate 37, respectively.

The output of the NOR gate 36 is given to light emitting diodes 38l and 38r provided in the left and right steering sensors 30l and 30r, respectively, and the output of the NOR gate 37 is also given to the left and right steering sensors 30r.
Light emitting diode 3 provided in each of l and 30r
9l, 39r. In addition, the output of each NOR gate 36, 37 is FET 44, 4, which will be described later.
7 gates respectively.

The output of each J-K flip-flop 34, 35 will be explained based on the time chart of FIG. 5. The _Q1 output of the J-K flip-flop 34 is the negative progression of the pulse signal (FIG. (FIG. 5B), thus dividing the input pulse by half the frequency, and the _Q1 output is a complementary pulse signal of the _Q1 output (FIG. 5C).

Similarly, the J-K flip-flop 35 divides the input pulse into 1/2 frequency.
The _Q2 output of the K flip-flop 35 is inverted by the negative progression of the _Q1 output of the JK flip-flop 34, and outputs the pulse signal shown in FIG. 5D. Also
The Q ₂ output is a complementary pulse signal of the Q ₂ output (5th
Figure H). Each of the NOR gates 36 and 37 outputs a high level signal when both of its inputs are at a low level (FIG. 5F and G), and the light emitting diode 38l
and 38r, 39l, and 39r to emit light, respectively, and FETs 44 and 47, which will be described later, are respectively brought into conduction.

Therefore, each light emitting diode 38l, 38r, 39
l, 39r are photodiodes 40l, 40r
It is modulated and driven with a pulse of about 9.8 kHz so that it can be distinguished from sunlight or lighting at 120 Hz or 100 Hz.

The light emitted from the light emitting diode 38l or 38r, 39l or 39r is reflected by the already planted seedlings Z, and the photodiode 40l or 39r whose cathode is connected to a terminal 10 which outputs a reference potential of 6.4V of a comparator 20 to be described later. The light is received at 40r. An output current corresponding to the amount of incident light is obtained from the photodiode 40l or 40r, and each output current is outputted to an AC amplifier circuit 42 via a buffer amplifier 41, amplified by the AC amplifier circuit 42, and passed through a bandpass filter 43. is output to.

The bandpass filter 43 is the light emitting diode 3
It allows only frequencies within a predetermined range centered around 9.8kHz of the modulated light emitted by 8l or 38r, 39l or 39r to pass through, and its output is
The signal is applied to the peak hold circuit 45 via the FET 44 and to the peak hold circuit 46 via the FET 47. FET44,4
As mentioned above, the outputs of the NOR gates 36 and 37 are applied to the respective gates, and when a high level signal is applied to each gate, the gates become conductive and pass the output of the bandpass filter 43 to each peak hold circuit 45. , 46. The outputs of both peak hold circuits 46 and 47 are then added together and input to the DC amplifier circuit 51, where the potential difference V ₅₁ with respect to the reference potential of 3.2V (=6.4/2V) is calculated.
is obtained and output to the input terminal 8 to which a voltage defining the midpoint of the window of the window comparator 20, which will be described later, is to be applied. Therefore, the terminal 8 of the window comparator 20 receives a signal having information related to the difference in the amount of reflected light from the already planted seedlings captured by the photodiode 40l or 40r.

Furthermore, the outputs of the peak hold circuits 45 and 46 are the +inputs of the comparators 52 and 53, respectively, and one input terminal of each comparator 52 and 53 is connected between the terminal 10 of the window comparator 20 to be described later and the body ground. The connection point between the 4.3 kΩ resistor R ₁ and the 5.1 kΩ resistor R ₂ inserted in the 4.3 kΩ resistor R ₃ and the 5.1 kΩ resistor
_R4 , and each comparator 52,
53 is one input. Comparators 52, 53
outputs a high level signal when its + input becomes larger than its - input, and the respective high level outputs are given to switch circuits 54 and 55, respectively, to turn them on and turn on the side marker. 8l, 8
Lamps 56l, 57l, 56 provided in each r
Turn on r and 57r, respectively. Also, comparators 52, 5
The anodes of diodes 58 and 59 are connected to the output terminal of 3, respectively, and the connection point between the two cathodes is connected to the negative input terminal of the comparator 61. An electrolytic capacitor 62 connected to the positive line of the battery 31 is connected to the negative input terminal of the comparator 61, and is also grounded to the body through a series circuit of a resistor _R5 and a variable resistor _R6 for setting a time constant. Comparator 6
The + input terminal of 1 is connected to the connection point of the resistors R ₁ and R ₂ mentioned above, and the window comparator 20
1/2 of the reference potential output from terminal 10 (=3.2V)
A potential slightly higher than that is input. Comparator 6
The output terminal of No. 1 is connected via a resistor to the base of a transistor 63 whose emitter is grounded to the body, and the collector of the transistor 63 is connected to the base of a transistor 73 whose emitter is grounded to the body. It is connected to diodes 71 and 72 connected to terminals 4 and 12 of the comparator 20, respectively, and a limit switch 68. The collector of the transistor 73 is connected to the diodes 71 and 7 via the buzzer 64.
2 and limit switch 68.

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, reference numeral 11 denotes a power supply terminal, which is connected to the positive terminal of a battery 31 via a switch 32 which is to be closed when automatic steering is selected. The terminal 10 of the window comparator 20 is connected to the ground terminal 1 when a predetermined voltage is applied to the power supply terminal 11.
This is a terminal that emits a constant voltage of 6.4V as the aforementioned reference potential, and in addition to being connected as described above, it is also connected to one end of the steering sensor 69. The steering sensor 69 is composed of a potentiometer connected to a rod of a hydraulic cylinder 92, and the other end is grounded via a resistor. The output voltage V ₆₉ of the steering sensor ₆₉ changes depending on the advance and retreat positions of the rod of the hydraulic cylinder 92, and becomes a signal representing the steering angle. , 7. The steering sensor 69 indicates that the steering angle is 0 degrees (the aircraft is moving straight).
It is set so that V ₆₉ =3.2V (=6.4/2V) when the voltage is . It is also connected to the rod of the hydraulic cylinder so that when the steering is steered to the left, the _V69 increases, and conversely, when the steering is steered to the right, the _V69 decreases.

As shown in FIG. 6, the terminal 8 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 output terminal of the DC amplifier circuit 51, so that the potential V ₅₁ is applied to the terminal. 8
given to.

The aforementioned terminal 10 is also connected to a fixed resistor R ₇ of 9.1 kΩ.
It is grounded through a series circuit with a variable resistor R ₈ of 1 kΩ, and the intermediate terminal potential of the variable resistor R ₈ is applied to the terminal 9 of the window comparator 20 . terminal 9
The input voltage V ₉ to defines the 1/2 width of the window as shown in FIG.

Terminals 4 and 12 are terminals that inhibit the output operation of the window comparator 20 when set to ground potential, and terminals 4 and 12 are connected to diodes 71 and 12, respectively.
It is connected to the connection point between the input terminal of the transistor 63 and the output terminal of the comparator 61 via the transistor 72, and to the collector of the transistor 63 and the buzzer 64 via the resistor as described above.

Terminals 2 and 14 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, so that when the respective outputs become low level, solenoids 91r and 91l are activated. It is designed to excite each of them.

Between the positive electrode line that is opened and closed by the switch 32 and the body ground, there is connected in parallel a series circuit consisting of an automatic selection lamp 65 whose lighting indicates the closing of the switch 32, a normally open limit switch contact 66, and a straight ahead indicator lamp 67. It is connected. This limit switch is placed facing the rotation range of the pitman arm 102, and its normally open contact 66 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 67. Further, the positive electrode line is connected to a buzzer 64 via a limit switch 68. The limit switch 68 is disposed near the steering wheel 101, and is configured to close when the steering wheel 101 is moved forward as in the case of seedling succession.

Next, the operation of the window comparator 20 will be briefly explained based on FIG.

Figure 6 A and B are binary outputs of terminals 2 and 14, respectively.
V ₂ and V ₁₄ are shown with V ₆₉ taken on the horizontal axis.
V ₁₄ is low level when V ₆₉ < V ₅₁ − V ₉ , V ₆₉ > V ₅₁ −
High level at V ₉ , and V ₂ is V ₆₉ < V ₅₁ + V ₉
It becomes high level when V ₆₉ > V ₅₁ + V ₉ , and becomes low level when V 69 > V 51 + V 9. The range from V ₅₁ −V ₉ to V ₅₁ +V ₉ is called a window, with V ₅₁ defining the midpoint and V ₉ defining 1/2 of the width. In the proposed device, 1/2 width is specified.
V ₉ is fixed at an appropriately set value with variable resistor R ₈ , but V ₅₁ changes depending on the relative position between the aircraft and the planted seedlings Z, and V ₆₉ also changes depending on the steering condition. . 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 will be at a low level,
As a result of energizing the solenoid 91r or 91l, steering to the right or left will be performed. and
If V ₆₉ is within the window, i.e. V ₅₁ −V ₉ ~
If it is in the range of V ₅₁ + V ₉ , steering is not performed as a dead zone for steering control.

The window midpoint, ie, _V51 , has a meaning as information representing the relative position between the planted seedlings and the aircraft body, and this will be explained below.

The modulated light emitted from the light emitting diode 38l or 38r, 39l or 39r is reflected by the already planted seedlings Z and is received by the photodiode 40l or 40r. Light emitting diode 38 located
The light emitting area of 1 or 38L is the light emitting area of both light emitting diodes 3
It is closer to the right (or left) of the center front of 8l and 39l. Further, the light receiving area of the photodiode 40l is equally spaced from the center of both the light emitting diodes 38l and 39l on the left and right sides. When the currently planted seedling Z is located in front of the center of both the light emitting diodes 38l and 39l, the photodiode 40l receives the light equally from each of the light emitting diodes 38l and 39l. At this time, each light emitting diode 38, 39l
FETs 44 and 47 become conductive in synchronization with the light emission timing of each peak hold circuit 4.
Numerals 5 and 46 output potentials corresponding to the amount of light emitted by the light emitting diodes 38l and 39l and reflected from the already planted seedlings Z, respectively. When both the light emitting diodes 38l and 39l emit light and the amount of light reflected by the already planted seedlings is equal, the output potential V51 of the DC amplifier circuit ₅₁ becomes 3.2V (=6.4/2V). Regarding the left sensor 30l, the planted seedling Z has both light emitting diodes 3
If the machine is deviated to the left (or right) side from the center front of 8l or 39l (that is, the machine is deviated to the right (or left) from the row of planted seedlings), the photodiode 40l More light emitted from the light emitting diode 39l or 38l located on the right (or left) side and reflected by the already planted seedlings will be received, and the potential V ₅₁ will be high (or lower). The same applies to the right steering sensor 30r.

Therefore, V ₅₁ is in an ideal running situation at 3.2V,
If it is larger than this, the aircraft is moving away from the row of already planted seedlings, and the sensor on the left (or right) side is 30l or 30l.
Looking at r, the situation is that the seedlings have shifted to the right (or left) from the planted seedlings. (or right) side sensor 30
When looking at l or 30r, it is in a situation where it deviates to the left (or right) from the row of already planted seedlings, and the smaller the value, the greater the deviation.

In this way, V ₅₁ has information indicating the position of the machine relative to the row of planted seedlings, that is, the left and right light emitting diodes 38l,
Although the detection range of the steering sensor 30l or 30r includes information on the difference between the projected light and the reflected light from the steering sensor 39l, there is a limit to the detection range of the steering sensor 30l or 30r. However, as will be described later, as long as the switch to automatic steering is performed under the condition that the aircraft is moving straight and the seedling Z is detected by the sensor, the steering control will not become 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, the steering wheel 10 is moved so that the steering sensor 30l on the left side follows the row of planted seedlings.
When the automatic steering selection switch 32 is closed while performing manual steering according to step 1, the automatic lamp 65 lights up. Then, when the photodiode 40l of the steering sensor 30l captures the light emitted from the light emitting diode 38l or 39l and reflected by the already planted seedlings, the output of the peak hold circuit 45 or 46 becomes a potential corresponding to the amount of light received. When this becomes higher than the - input of the comparator 52 or 53, a high level signal is output to the switch circuit 54 or 55 to turn it on, and the lamps 56l or 57l, 56r or 57r attached to the side markers 8l and 8r light up. do.

Therefore, when manually steering the aircraft to follow the row of planted seedlings, if the row of planted seedlings is on the left (or right) side of the aircraft, the driver should use the side marker 8l or 8r on the left (or right) side. All you have to do is to steer while looking at it, and when the steering sensor 30l or 30r detects a planted seedling, the side marker 8l or 8r will turn on the lamp 56.
Since light is emitted when either 1, 57l or 56, 57r is lit, the driver can easily know that it is now possible to shift to automatic steering.

Under these circumstances, when the aircraft is able to travel straight, the limit switch 66 is turned on and the straight travel indicator lamp 67 lights up. 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. I realized that I was getting older, and at this point the steering wheel was 10.
Move 1 forward. Then, the limit switch 68 is turned on, and if a row of already planted seedlings exists on the left side, automatic steering is performed by the steering sensor 30l.

In automatic steering, the light emitting diodes 38l and 39l are driven according to the timing determined by the pulse oscillator 33 and the J-K flip-flops 34 and 35, and the light emitted by each light emitting diode 38l and 39l is reflected by the already planted seedlings to the photodiode 40l. This is done by detecting the reflected light of each light emitting diode 38l, 39l in synchronization with the drive timing of each light emitting diode 38l, 39l.

Then, for some reason, the aircraft moves to the right (or left).
When the light emitting diode 3 on the left (or right) side
The amount of light emitted by 8l or 39l and reflected by the already planted seedlings and received by the photodiode 40l is emitted by the right (or left) side light emitting diode 39l or 38l and reflected by the already planted seedlings. The amount of light received by the reflected light is greater than that captured by the photodiode 40l, and the DC amplifier circuit 5
The output potential V ₅₁ of 1 becomes larger (or smaller) than 3.2V, and the window moves to the high (or low) voltage side. Output potential of steering sensor 69 V ₆₉
Since the limit switch 66 was turned on and the automatic steering was switched on, it is at 3.2V (straight ahead) or a value close to this, but by moving the window to the high voltage side (or low voltage side), it is V ₁₄ or V ₂ becomes low level and the solenoid 91l or 91r is energized, and as a result, the machine corrects its traveling direction to the left (or right), and the machine returns to the state of following the already planted seedling row. This operation is the same even when the aircraft has deviated significantly to the right (or left), but in this case, the amount of movement of the window toward the high (or low) voltage side is large, so temporary commands and rudder Even if the output of the sensor 69 is slightly higher (or lower) than 3.2V,
That is, even if the direction is being corrected to the left (or right), V ₁₄ or V ₂ becomes a low level, the solenoid 91l or 91r is energized, and the hydraulic cylinder 92 is actuated to move left (or right). The amount of steering to the right (or to the right) is increased to quickly return the vehicle to a straight traveling state.

Steering sensor 3 on the left (or right) side like this
While the steering control by 0l or 30r is being performed, the other steering sensor 30r or 30l is connected to the light-emitting diodes 38r, 39 of the right (or left) sensor 30r or 30l because there are no planted seedlings.
The photodiode 40r or 40l located below cannot capture the light emitted from the left (or right) sensor 30l or 30r and reflected by the already planted seedlings.
The light captured by the photodiode 40l or 40r is filtered by the bandpass filter 43, and only the light emitted from the light emitting diodes 38l, 39l or 38r, 39r of the left (or right) sensor 30l or 30r and reflected by the already planted seedlings is filtered. Therefore, there is no problem with automatic steering whether the left or right side is used as a reference.

Furthermore, in the present device, if the photodiode 40l or 40r cannot capture the reflected light from the already planted seedlings, for example, when the aircraft reaches a headland, the photodiode 40l or 40r will
If the state in which the light emitted from 8l or 38r, 39l or 39r and reflected by the already planted seedlings cannot be detected continues for a predetermined period of time or more, an alarm is issued. That is, the + inputs of the comparators 52 and 53 become low potential, and the outputs of the comparators 52 and 53 become low level. Then capacitor 6
2 starts discharging, and when this low level time continues for a time determined by the capacitor 62, resistor _R5 , and variable resistor _R6 , the output of the comparator 61 becomes low level, the transistor 63 is turned off, and the transistor 73 is turned off. It turns on and the buzzer 64 sounds. Also, by turning off the transistor 63, the window comparator 2
0 terminals 4 and 12 are at ground potential, the window comparator 20 is in a state where output operation is prohibited, and there is no risk that the aircraft will run onto a ridge or the like or run in an unexpected direction.

The present device has a simple structure and is economical because the relative position between the planted seedlings and the machine body can be detected in an analog manner. Furthermore, since it is hardly affected by noise, control reliability and stability are high. Furthermore, since it uses modulated light to capture the reflected light from the already planted seedlings,
It is possible to detect already planted seedlings located far from the aircraft without being affected by external light, and by using the already planted seedlings as a guide for automatic steering, the planting can be done with almost no risk of hunting. The attached locus can be made substantially constant. It is also economical because it is only necessary to use one expensive photodiode as a light-receiving element on the left and right sides of the fuselage. Furthermore, since the projection areas of the light emitting elements are different on the left and right, the area for monitoring the already planted seedlings is wide, and the already planted seedlings, which are to be followed by steering, will not be lost. This increases steering control accuracy and stability. The number of light emitting diodes as light emitting elements may be three or more on each of the left and right sides of the aircraft body. In this case, the light emitting area is expanded and more precise steering becomes possible.

Furthermore, since the structure is such that the reflected light from each planted seedling is detected in synchronization with the driving timing of each light emitting diode, only one oscillation circuit is required for modulating and driving the light emitting diodes, which reduces the number of components. By performing synchronous detection, reliability is improved.

As described in detail above, the present invention uses an automatic steering device for a transplanter that detects the relative positional relationship between the already planted seedlings and the machine body and causes the machine to travel along the rows of already planted seedlings, by alternately projecting modulated light. In addition, there are a plurality of light emitting elements with different projection areas on the left and right, one light receiving element that receives the reflected light from the planted seedlings of the light projected by each light emitting element, and each of the reflected lights synchronized with the projection timing of each modulated light. It is equipped with a means for detecting the difference in the amount of received reflected light by performing light detection, and is configured to detect the relative positional relationship between the planted seedlings and the aircraft based on the detection results, so automatic steering control is easy to use. Accuracy and stability are improved. Further, by using an analog circuit, using a single light receiving element, and using a common oscillation circuit, an economically superior automatic steering system can be realized.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention.
The figure is a left side view of a riding rice transplanter equipped with the proposed device, Figure 2 is its main electronic circuit diagram, Figure 3 is a plan view showing the light emitting area of the light emitting diode, and Figure 4 is the light receiving area of the photodiode. FIGS. 5A to 5D are time charts for explaining the operation of the present device, and FIGS. 6A and 6B are diagrams illustrating the operation of the window comparator. 20...Window comparator, 30l, 30
r... Steering sensor, 33... Pulse oscillator, 3
4,35...J-K flip-flop, 36,3
7...NOR gate, 38l, 38r, 39l,
39r...Light emitting diode, 40l, 40r...
Photodiode, 42...AC amplifier circuit, 43
...Band pass filter, 44, 47...FET,
45, 46... Peak hold circuit, 51... DC amplifier circuit, 52, 53, 61... Comparator, 64
...Buzzer, 69...Steering sensor, 91l, 91r
... Solenoid, 92 ... Hydraulic cylinder.

Claims (1)

[Scope of utility model registration request] The automatic steering system of the transplanter, which detects the relative positional relationship between the planted seedlings and the machine body and causes the machine to travel along the rows of already planted seedlings, alternately projects modulated light, and also uses a plurality of systems with different projection areas on the left and right. A light-emitting element, one light-receiving element that receives the reflected light from the planted seedlings of the light projected by each light-emitting element, and each reflected light is detected by detecting each of the reflected lights in synchronization with the projection timing of each modulated light. 1. An automatic steering device for a transplanter, comprising means for detecting a difference in the amount of light received, and based on the detection result, the relative positional relationship between the planted seedlings and the machine body is determined.