JPS641081B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control system for an automatic steering device in a traveling agricultural machine such as a rice transplanter or other transplanting machine.

In a transplanting machine such as a rice transplanter, it is extremely important to plant seedlings in an orderly straight line for uniform growth of seedlings, mechanization of harvesting work, etc. For this purpose, various automatic steering devices have been proposed that steer the aircraft so that it goes straight. Many of them include the above problems.

The present invention provides an automatic steering control system that solves the above-mentioned problems by compositely using the deflection amount and deflection angle of the aircraft as data for setting the steering angle. With the goal.

The automatic steering control system according to the present invention measures the amount of deviation of the agricultural machine with respect to the steering guide means that the agricultural machine should follow when traveling, and calculates the amount of change in the amount of deviation within a predetermined time and The deflection angle in the advancing direction of the agricultural machine is calculated based on the traveling distance of the machine, and if the deflection angle is larger than a predetermined value, the steering angle is adjusted according to the deflection angle, and if the deflection angle is smaller than the predetermined value, the steering angle is adjusted. If the displacement amount is larger than a predetermined value, the steering angle is set in accordance with the displacement amount.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to drawings showing embodiments of a riding rice transplanter.

FIG. 1 is a schematic plan view of a riding-type rice transplanter according to the present invention, and FIG. 2 is a schematic diagram of an automatic steering device according to the present invention. The fuselage has a foldable body structure in which the front and rear separate parts are pivotally connected, and can be operated by rotating a steering wheel 5 for manual steering or for automatic steering connected to a steering shaft 5a that rotates in conjunction with this. By the rotational drive of the pulse motor 33, the rear body 4, to which the rear wheels 3, 3 are attached, is horizontally rotated left and right relative to the front body 2, to which the front wheels 1, 1 are attached, for steering. I have to. Reference numerals 6 and 6 are sensors, and one each is arranged at positions extending left and right from the front fuselage 1.
6 uses a row of seedlings that have already been planted as a steering guide means, so in each step, one of the sensors, that is, the sensor 6 on the left in the case of FIG. 1, is selected and used.

Note that the outermost seedling row Q of the already planted seedling rows, that is, the seedling row Q on the side of the current seedling planting process, is selected as the steering guide means.

The sensor 6 includes two photo interrupters 61,
62 are arranged so that their respective light beams intersect in plan view, and the photo interrupter 6
Light beams P ₁ and P ₂ emitted from one light emitter 61a and 62a, respectively, intersect at the seedling row Q, and are received by light receivers 61b and 62b. Therefore, each time the seedlings q of the seedling row Q pass through the light beams P ₁ and P ₂ as the aircraft moves forward, the light receivers 61b and 62b become light-blocked and emit pulse signals R ₁ and R ₂ . Become.

These pulse signals R ₁ and R ₂ are input to the arithmetic control circuit 31, which issues a control signal to the motor drive circuit 32. Based on this, the motor drive circuit 32 performs the necessary steering operations. The pulse motor 33 is rotated by the step.

Data processing based on the pulse signals R ₁ and R ₂ within the arithmetic control circuit 31 will now be described.
First, as shown in FIG. 3, the pulse signal R ₁ or R ₂
period t ₂ and the difference t ₁ between the periods of both pulse signals R ₁ and R ₂ ,
In other words, the difference in timing of occurrence is read one after another.

Therefore, when the intersection of the light beams P ₁ and P ₂ coincides with the seedling row Q, the light beams P ₁ and P ₂ are simultaneously blocked by the seedlings q, so t ₁ = 0. On the other hand, when the above-mentioned intersection deviates from the seedling row Q, t ₁ ≠ 0, and its value and sign are determined by the deviation amount and direction between the intersection and the seedling row Q, so in short, from the value of t ₁ The amount of deviation of the aircraft with respect to the seedling row Q, which serves as a steering guide means, is determined. FIG. 4 schematically shows the alignment direction of the seedling row Q, the traveling direction D of the machine body, and the position of the sensor 6, and the above deviation corresponds to l in the figure.

Now, since the pitch between the seedlings in the seedling row Q is approximately constant, _t2 changes in inverse proportion to changes in the aircraft speed. Arithmetic control circuit 31
calculates the speed of the aircraft from t ₂ and calculates the distance traveled by the aircraft during a certain period of time and the change in l during that time. Then, based on both of these, the deviation angle θ of the aircraft traveling direction D with respect to the seedling row Q is determined.

Note that the period t ₂ of the pulse signal R ₁ or R ₂ does not have a strictly inversely proportional relationship to the aircraft speed.
That is, if the amount of deviation of the aircraft differs between successive pulse generation timings, the amount of difference will be included as an error factor. For example, regarding the light beam _P1 , if the aircraft deviates to the right after one pulse appears, the timing at which the next seedling q passes through the light beam _P1 will be such that this seedling will move relatively toward the light emitter 61a. Therefore, it becomes faster and t ₂ becomes shorter.

The same applies to the direction of movement of the aircraft, and if the deviation angles differ between successive pulse generation timings, the amount of difference will be included as an error factor. For example, regarding the light beam _P1 , if the aircraft changes its traveling direction clockwise after one pulse appears, the timing at which the next seedling q passes through the light beam _P1 is such that this seedling is relatively on the side of the light emitter 61a. Since it will move closer to the center, it will be faster and t ₂ will be shorter.

However, if the aircraft deviates to one side due to field conditions, or if the direction of travel is directed to one side, that direction is detected by the positive or negative of _t1 and this is resolved, as explained below. The control to be performed, ie, the control to deflect in the opposite direction or to change the direction of travel, will be performed.
As long as appropriate steering control is performed, large deviations or deviations in the signal direction will not remain unresolved during the generation of many pulses. Therefore, it goes without saying that t ₂ is approximately inversely proportional to the aircraft speed. In addition, the aircraft speed information obtained from t ₂ will be mixed with positive and negative error factors due to the alternating occurrence of deviations in the opposite direction, so multiple pieces of information cannot be said to be accurate speed information. can.

Therefore, in order to compensate for such error factors, it is sufficient to calculate the aircraft speed based on _t2 , which has been subjected to well-known moving average processing.

Next, a method for calculating l and θ will be explained.

Assuming that θ=0, the product tv of the difference t ₁ between the generation timings of the pulse signals R ₁ and R ₂ and the aircraft speed v is the seedling row Q
This corresponds to the distance between the intersections of the light beams P ₁ and P ₂ , respectively (see FIG. 6). Since the intersection angle of the light beams P ₁ and P ₂ is known, the amount of deviation l from the intersection of the light beams P ₁ and P ₂ can be calculated from the geometrical calculation of this intersection angle and tv. For example, as shown in the figure, the light beam P ₁ ,
Assuming that P ₂ is in a perpendicular relationship tilted at an angle of 45 degrees with respect to the aircraft's traveling direction, then l=tv/2.

Similarly, by at least one more t ₁
The values of l obtained in this way are set as l ₁ and l ₂ (see Fig. 7). Then _, the cumulative sum of t ₂ between the times when l 1 and l ₂ were obtained (that is, the time difference between the respective timings when l ₁ and l ₂ were obtained. l ₁ and l ₂ were calculated from the successive t ₁ Since the steering distance of the aircraft during this Σt ₂ can be calculated from the product of Σt ₂ and v, the deflection angle _θ can be calculated as θ=l ₂ −l ₁ /Σt ₂ v(rad). It can be calculated.

The error due to assuming θ = 0 is actually θ
Since the absolute value of θ is small at about 2°, it can be ignored, but if you want to find it more accurately,
What is necessary is to perform an iterative process of correcting l using , and then calculating θ based on the corrected l value.

Now, FIG. 5 is a flowchart showing the concept of the automatic steering control system according to the present invention. First, the deviation angle θ is detected as described above (). Then,
Compare θ with the allowable angle θ ₀ determined in consideration of the dead zone (), and if θ > θ ₀ (YES), calculate the steering angle required to correct this, that is, to make θ zero. set(); Steering is then performed by transmitting this signal to the motor drive circuit 32 and rotating the pulse motor 33 (). Following this,
Or, if θθ is ₀ (NO), l is detected as described above (). Then, l is compared with the allowable amount l ₀ determined in the same way as θ ₀ (), and if l > l ₀ (YES), the steering angle is corrected to make l zero (), and the steering angle is adjusted based on this. (). and,
The steps , , , are repeated until ll ₀ is reached.

Since the method of the present invention is performed as described above, even if the deviation angle is small but the deviation from the steering guide means is large, steering is performed until l becomes zero, and the width The assignment is done accurately. In addition, when steering is performed to make the deviation angle zero,
Because of this steering, when the amount of deviation exceeds the allowable amount, the steering is performed in the opposite direction, that is, the steering angle is returned, so there is no possibility of oversteering or even hunting of the control system. , the present invention has excellent effects on improving the control function and accuracy of automatic steering devices for agricultural machinery.

The present invention is not limited to the above-mentioned embodiments, but can be applied to combine harvesters and other running agricultural machines in general, and the steering guidance means may be other than plants, such as underground cables, and the sensor may be an optical system. Of course, in addition to mechanical devices such as limit switches, the device may also be of the type that traces electromagnetic waves.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1 is a schematic plan view of a riding-type rice transplanter according to the present invention;
Fig. 2 is a schematic diagram of the automatic steering system, Fig. 3 is a waveform diagram of the pulse signal output by the sensor, Fig. 4 is an explanatory diagram of the deflection angle and amount, and Fig. 5 is a diagram of the method of the present invention. The flowcharts of FIGS. 6 and 7 are explanatory diagrams of the method of calculating l and θ, respectively. 5... Steering wheel, 6... Sensor, 31... Arithmetic control circuit,
33...Pulse motor.

Claims (1)

[Claims] 1. When the agricultural machine runs, measure the amount of deviation of the agricultural machine with respect to the steering and guiding means that it should follow,
The deviation angle in the advancing direction of the agricultural machine is calculated based on the change in the amount of deviation within a predetermined time and the distance traveled by the agricultural machine during that time, and if the deviation angle is larger than a predetermined value, the deviation angle is calculated according to the deviation angle. An automatic steering control system characterized in that the steering angle is set according to the deflection amount, and when the deflection angle is smaller than a predetermined value and the deflection amount is larger than a predetermined value, the steering angle is set according to the deflection amount.