WO2019004077A1

WO2019004077A1 - Harvesting machine

Info

Publication number: WO2019004077A1
Application number: PCT/JP2018/023790
Authority: WO
Inventors: 北原麻央; 井上大嗣; 高原一浩; 池田博
Original assignee: 株式会社クボタ
Priority date: 2017-06-26
Filing date: 2018-06-22
Publication date: 2019-01-03
Also published as: CN110753491B; JP6754723B2; JP2019004789A; KR20200019600A; KR102596706B1; CN110753491A

Abstract

This harvesting machine is provided with a threshing device, a grain tank which stores grain recovered by the threshing device, a grain transport path on which the grain is transported from the threshing device to the grain tank, a harvest amount sensor which detects pressure based on the amount of grain passing through the grain transport path, a yield amount conversion unit which converts a detection value detected by the yield amount sensor to a yield amount value representing the yield amount, and a storage unit in which multiple conversion tables are stored which have different conversion ratios for converting detection values to yield amount values. At the time of conversion of detection values, the yield amount conversion unit selects one of the multiple conversion tables depending on the size of the detection values and uses the selected table for conversion.

Description

Harvester

The present invention relates to a harvester.

For example, Japanese Unexamined Patent Publication No. 2017-077204 is provided with a throwing plate (in the literature, "rotary blade plate") for releasing grains sent from a threshing apparatus by a screw conveyor from a grain outlet, A combine is disclosed in which a yield sensor ("literary sensor" in the literature) is provided inside the tank. The grains emitted by the throwing plate impinge on the yield sensor and the impact of the impact is detected by the strain gauges of the yield sensor. The distortion amount of the yield sensor is converted to a voltage, and the grain amount is calculated by the control unit.

Japanese Patent Application Laid-Open No. 2017-077204

However, when the amount of grains released to the grain tank decreases, grains may be released in a state of being biased to the side where the threshing device is located among the grain discharge ports. At this time, the pressure distribution applied to the yield sensor varies, and the strain amount of the yield sensor may be smaller than the actual amount of grain. As a result, the detected amount detected by the yield sensor does not have a linear proportional relationship with the actual grain yield, and an error between the calculated yield value and the actual yield based on the detected amount Was likely to occur.

In view of the above-mentioned situation, there is a demand for a harvester capable of accurately calculating the yield of grains discharged from the grain transfer path to the grain tank based on the detection value of the yield sensor.

A harvester according to the present invention comprises a threshing device, a grain tank for storing grains collected by the grain threshing device, a grain conveyance path for conveying grains from the grain throttling device to the grain tank, and the grain A yield sensor for detecting a pressure based on the amount of grain passing through a grain transfer path, a yield conversion unit for converting a detection value detected by the yield sensor into a yield value representing a yield, and the yield A storage unit storing a plurality of conversion tables having different conversion ratios to be converted into values, the yield conversion unit converting the plurality of conversion tables according to the magnitude of the detection value when converting the detection value And one conversion table is selected and used for conversion.

According to the present invention, by selecting one from the plurality of conversion tables according to the magnitude of the detected value, the yield conversion unit can convert the detected value into the yield value while switching the conversion ratio. According to the configuration in which the conversion table has a conversion ratio optimized such that the actual yield and the yield value are close to each other within the detection range within a specific range, the yield conversion unit is optimum according to the range of detection values. You can select a conversion table. As a result, it is possible to accurately calculate the yield of grains discharged from the grain transfer path to the grain tank based on the detection value of the yield sensor.

In the present invention, it is preferable that the conversion table select a conversion table with a smaller conversion ratio as the detected value is larger, and select a conversion table with a larger conversion ratio as the detected value is smaller.

With this configuration, the yield conversion unit should select a conversion table having a large conversion ratio, even when the amount of released grain is small and the amount of distortion of the yield sensor decreases relative to the actual amount of released grain. By this, the accuracy of the yield value calculated from the detected value is improved.

In the present invention, in the storage unit, as the plurality of conversion tables, a first table used when the detected value is smaller than a first threshold, and the detected value is higher than the first threshold and the first threshold. A second table used when it is between a large second threshold and a third table used when the detected value is larger than the second threshold are stored, and the conversion in the first table is performed. The ratio is a constant value, the conversion ratio in the third table is a constant value of a value different from the conversion ratio of the first table, and the conversion ratio in the second table is the value of the first table. It is preferable that the conversion ratio and the conversion ratio of the third table linearly change according to the detected value so as to be linearly complemented.

The detection value may slightly change while crossing the first threshold or the second threshold, and the selection of the conversion table may be switched. At this time, if the value of the conversion ratio changes significantly due to switching of the conversion table, the yield value calculated based on the detected value may change significantly, and a large error may occur with respect to the actual yield. With this configuration, even if the detection value changes slightly while crossing the first threshold or the second threshold and the selection of the conversion table is switched, the value of the conversion ratio hardly changes, and the yield The change in value is also small. Therefore, a large error does not occur in the yield value calculated from the detected value and the actual yield, and the accuracy of the yield value is improved.

In the present invention, in the storage unit, the plurality of conversion tables are used when the detection value is between a third threshold larger than the second threshold and a fourth threshold larger than the third threshold. Four tables and a fifth table used when the detected value is larger than the fourth threshold are stored, and the conversion ratio in the fifth table is the conversion ratio of the first table and the conversion ratio. The conversion ratio of the third table is a fixed value different from the conversion ratio, and the conversion ratio of the fourth table is such that it linearly complements the conversion ratio of the third table and the conversion ratio of the fifth table. And the proportional change rate of the conversion ratio in the second table is proportional to the change rate of the conversion ratio in the fourth table. Ri is also a large and suitable.

If the amount of grain discharged to the grain tank increases, the grain is pressed against the yield sensor evenly, and the pressure distribution applied to the yield sensor becomes stable, so the detected value by the yield sensor and the actual yield Approaches a linear proportional relationship. With this configuration, when the detected value changes between the third threshold and the fourth threshold, the change in conversion ratio is smaller than when the detected value changes between the first threshold and the second threshold. It becomes loose. As a result, the change in the yield value calculated from the detected value also approaches linear proportionality as much as possible. As a result, the accuracy of the yield value when the amount of kernel release is large is improved.

It is a right side view of a combine. It is a top view of a combine. It is a combine rear view which shows a grain conveyance path and a grain tank. FIG. 2 is a longitudinal side view of a grain release device and a yield sensor. It is a block diagram showing a yield calculation unit. It is a figure which shows the conversion table which converts the detected value and yield value of a load cell. It is a graph which shows the relationship between the detected value of a load cell, and a conversion ratio. It is a graph which shows the relationship between the detected value of a load cell, and a yield value. It is a figure which shows another embodiment of the conversion table which converts the detected value and yield value of a load cell. FIG. 10 is a plan view of another embodiment of a grain emission device and yield sensor.

[Basic configuration of harvester]
An embodiment of a harvester according to the present invention will be described based on the drawings. In the present embodiment, the left side or the right side in the machine body width direction defines left and right in a state in which the machine body travels in the direction of travel.

1 and 2 show a conventional combine that is an example of a harvester. An airframe frame 1 in which a plurality of steel materials are connected is provided in a harvester, and a pair of left and right crawler traveling devices 2 is provided in a lower portion of the airframe frame 1. An engine E is mounted on the front right portion of the fuselage frame 1, and a driving cabin 3 is provided above the engine E. A reaper 4 is attached to the front of the machine frame 1 so as to be able to move up and down. A threshing device 6 for threshing the whole of the reaping grain gutter supplied from the reaper 4 by the conveying feeder 5 at the rear of the airframe frame 1 And are mounted side by side in the left-right direction. In addition, the unloader 8 mounted adjacent to the grain tank 7 discharges the grain stored in the grain tank 7 to the outside. A weight sensor 40 is provided at the front lower end of the grain tank 7, and the weight sensor 40 detects the grain yield based on the total weight of the grain tank 7.

[Grain transport route]
As shown in FIG. 3, the threshing device 6 and the grain tank 7 are connected by a grain conveyance path 10. In the grain conveyance path 10, a first thing conveyance screw 10A provided at the bottom of the threshing device 6, a lifting conveyor 10B disposed between the threshing device 6 and the grain tank 7, and the grain tank 7 And a transverse feed screw 10C penetrating the front upper portion of the left side wall. The lift conveyor 10B is a bucket conveyor, and an endless rotation chain 10E is wound around a sprocket 10D so as to extend across the transport direction both ends of the lift conveyor 10B, and a plurality of buckets 10F are provided on the outer peripheral side of the endless rotation chain 10E It is provided at regular intervals. The grains collected at the bottom of the threshing device 6 are discharged to the right lateral side outward of the threshing device 6 by the one-piece conveying screw 10A, and then transported upward of the grain tank 7 by the lifting conveyor 10B. And transported from the outside to the inside of the grain tank 7 by the crossfeed screw 10C.

As shown in FIG. 3 and FIG. 4, a grain discharging device 11 for splashing grains to the inside of the grain tank 7 is provided at the end region of the grain conveyance path 10. The grain releasing apparatus 11 is provided with a releasing rotating body 12 and a releasing case 13 which covers the periphery of the releasing rotating body 12. The discharge rotary body 12 has a rotary shaft 12A extended from the transverse feed screw 10C to the end in the conveying direction, and a rotary blade 12B having a throw plate 12B extending in one direction in the range from the rotary shaft 12A to the inner side of the discharge case 13 It is. A discharge port 13A is formed in a C shape on the rear side of the release case 13 in a side view of the airframe. The discharge port 13A is formed larger in the axial direction P of the discharge rotating body 12 than the width of the anchor plate 12B. The throwing plate 12B rotates in the direction indicated by the arrow R, and the grain transported to the discharge case 13 is pushed out of the discharge port 13A into the grain tank 7 by the throwing plate 12B.

A protrusion 12C is provided in a state of extending from the rotation shaft 12A to the opposite side to the side where the anchor plate 12B is located. The rotation of the projection 12C is detected by the rotation sensor 21 (FIG. 5), and a rotation pulse is generated at the timing when the projection 12C passes the rotation sensor 21, and one rotation is counted.

[Yield sensor]
As shown in FIG. 4, a yield sensor 20 for measuring the amount of release of the grain is provided in a state of being supported by the support frame 22 in a state of facing the discharge port 13A. The yield sensor 20 is provided with a flat detection plate 20A and a load cell 20B via a spacer 20C. A spacer 20D is provided between the load cell 20B and the support frame 22. Although not shown in detail, the spacer 20C is provided in contact with the upper end on one end side of the load cell 20B, and the spacer 20D is provided in contact with the lower end on the other end side of the load cell 20B. With this configuration, when a load is applied to the detection plate 20A, distortion of the load cell 20B is promoted.

The grain is discharged from the outlet 13A by the throwing plate 12B and pressed against the detection plate 20A. The pressing force of the kernel causes the load cell 20B to be distorted to generate an electric signal. This electrical signal is used as a detection signal for evaluating the grain yield, and, for example, the electrical signal is represented by a voltage value or a current value. As the amount of release of the grain sent from the grain transport path 10 increases, the pressing force of the grain on the detection plate 20A increases and the detection signal of the load cell 20B also increases.

When the release amount of the grain transported from the grain transport path 10 is large, the grain discharged from the discharge port 13A is splashed evenly from the entire width in the left and right width of the discharge port 13A. Along with this, since the grain is uniformly pressed against the detection plate 20A, the pressure distribution applied to the detection plate 20A becomes uniform. Therefore, if the release amount of kernels is large, the strain amount applied to the load cell 20B is proportional to the release amount of kernels. However, when the release amount of the kernel transported from the kernel transport path 10 is small, the kernel discharged from the outlet 13A is released in a state of being biased to the side where the threshing device 6 is located among the outlets 13A. Be done. In this state, since the grain is pressed against only a part of the detection plate 20A, the pressure distribution applied to the detection plate 20A is uneven or uneven, and the amount of distortion of the load cell 20B is reduced. From this, the relationship between the detection signal of the load cell 20B and the actual yield does not become linear proportional. The conversion table used to solve such a problem is described below.

[Conversion table]
The yield calculation unit 30 for calculating the yield value based on the detection signal of the load cell 20B will be described based on FIGS. 5 to 8. The yield calculation unit 30 is, for example, a module incorporated in a microcomputer mounted on the machine. The yield calculation unit 30 stores the input signal processing unit 31 which is an input interface, the yield conversion unit 32 which calculates the yield value based on the detection signal of the load cell 20B, and the conversion table T used for calculating the yield value. A storage unit 33 is provided. The input signal processing unit 31 is connected to the yield sensor 20 and the rotation sensor 21, and the detection signal of the load cell 20 B and the rotation pulse of the rotation sensor 21 are input to the input signal processing unit 31. By dividing the sequential waveform of the detection signal into each rotation pulse, the waveform of the detection signal in the section of one rotation can be obtained.

The grains sent from the crossfeed screw 10C are pushed out of the discharge port 13A to the outside of the discharge case 13 by the rotation of the throwing plate 12B and pressed against the detection plate 20A. At the timing when the throwing plate 12B passes through the outlet 13A, the amount of grains pressed against the detection plate 20A increases, and the pressing force applied to the detection plate 20A increases. The detection signal at this time has a maximum value in one rotation of the throwing plate 12B. The input signal processing unit 31 obtains the maximum value of the detection signal from the waveform of the detection signal for each rotation, and the maximum value of the detection signal is output to the yield conversion unit 32 as the detection value X. In the present embodiment, since the projection 12C is provided on the side opposite to the side where the throwing plate 12B is located from the rotation shaft 12A, the detection signal has a maximum value near the center of the section for one rotation.

The storage unit 33 stores a plurality of conversion tables T as shown in FIG. Each conversion table T has information in which the detection value X and the conversion ratio A are linked over an arbitrary range of the detection value X. The detected value X is output by the input signal processing unit 31, and one conversion table T including the detected value X within the detection range is selected by the yield conversion unit 32 from the plurality of conversion tables T. The number of tables is a numerical value determined as appropriate, but in the present embodiment, the five conversion tables T from the first table T1 to the fifth table T5 are stored in the storage unit 33 in a state in which they have different conversion ratios A. It is done. Five conversion tables T are divided by a first threshold X1, a second threshold X2, a third threshold X3, and a fourth threshold X4 according to the range of the detection value X. Here, the first threshold value X1, the second threshold value X2, the third threshold value X3, and the fourth threshold value X4 are numerical values appropriately determined.

When the plurality of conversion tables T are combined, as shown in the graph of FIG. 7, as the detected value X becomes larger, the value of the conversion ratio A falls to the right. That is, when the detection value X is small, the conversion table T having a large conversion ratio is selected and used for conversion by the yield conversion unit 32. When the detection value X becomes large, the conversion table T having a small conversion ratio is selected. It is used for the conversion of the yield conversion unit 32. For example, when the detected value X is less than the first threshold X1, the yield conversion unit 32 selects the first table T1, and when the detected value X is greater than or equal to the first threshold X1 and less than the second threshold X2, the yield The conversion table T is selected in a pattern that the conversion unit 32 selects the second table T2. In the present embodiment, the first threshold X1, the second threshold X2, the third threshold X3, and the fourth threshold X4 are the second table T2, the third table T3, the fourth table T4, and the fifth table T5. It is set as the lower limit value.

The yield conversion unit 32 obtains the conversion ratio A from the conversion table T selected based on the detection value X, and multiplies the conversion ratio A by the detection value X based on the following formula to calculate the yield value V. .

Yield value V = (A · X) + p
The yield value V represents the grain yield per unit travel distance of the harvester. p is an additional coefficient, and can be set to any value including zero and negative values.

The detection range of the first table T1, the third table T3 and the fifth table T5 is a range in which a linear proportional relationship is easily established by the relationship between the detection value X and the actual yield. For this reason, the first table T1, the third table T3 and the fifth table T5 respectively have single conversion ratios A10, A30, A50 so as to be constant over the entire range within the detection range. As shown in the graphs of FIGS. 6 and 8, the relationship between the detected value X (1 to 9) and the yield value V (V10 to V19) in the first table T1 is a linear proportional relationship. Further, the relationship between the detected value X (20 to 29) and the yield value V (V30 to V39) in the third table T3 is also a linear proportional relationship, and the detected value X (40 or more) and the yield value V in the fifth table T5. The relationship with (V50 or more) is also a linear proportional relationship. The conversion ratios A10, A30, and A50 are numerical values appropriately determined by experiments.

The selection of the conversion table T may be switched when the detection value X slightly changes while crossing any of the first threshold X1, the second threshold X2, the third threshold X3, and the fourth threshold X4. At this time, if the value of the conversion ratio A changes to a different value, even if the change in the detected value X is small, the value of the yield value V changes in a step shape, and the yield value V may deviate from the actual yield. There is. For example, as indicated by the broken line in the graph of FIG. 8, in the detection range of the second table T2, the yield value is calculated even with the same detection value X between the conversion ratio A10 and the conversion ratio A30. V takes different values. Therefore, the second table T2 and the fourth table T4 are configured such that the value of the conversion ratio A does not change significantly with respect to the change of the detection value X.

The second table T2 is configured such that the conversion ratios A20 to A29 of the second table T2 change in proportion to the detection value X in a state in which the conversion ratio A10 and the conversion ratio A30 are linearly complemented. Further, the fourth table T4 is configured such that the conversion ratios A40 to A49 of the fourth table T4 change in proportion to the detection value X in a state in which the conversion ratio A30 and the conversion ratio A50 are linearly complemented. . Therefore, as shown in the graphs of FIGS. 6 and 8, as the detected value X increases, the values of the conversion ratios A20 to A29 gradually decrease, and the values of the conversion ratios A40 to A49 also gradually decrease. It becomes smaller. As shown in the graphs of FIGS. 6 and 8, the relationship between the detected value X (10 to 19) and the yield value V (V20 to V29) in the second table T2 is drawn by a quadratic curve of the graph It becomes a relationship. Further, the relationship between the detection value X (30 to 39) and the yield value V (V40 to V49) in the fourth table T4 is also a relationship drawn by a quadratic curve of the graph.

With this configuration, even if the selection of the conversion table T is switched, the conversion ratio A and the yield value V change steplessly without changing in a step-like manner according to the continuous change of the detection value X, and detection The accuracy of the yield value V calculated based on the value X is improved.

As the amount of kernels discharged from the outlet 13A increases, the pressure distribution applied to the detection plate 20A becomes more stable, and the strain of the load cell 20B tends to be proportional to the amount of kernels released. Therefore, in the conversion table T having a configuration in which the conversion ratio A changes in proportion, the conversion ratio in the conversion table T on the side where the detection value X is smaller is the conversion ratio on the side where the detection value X is smaller. The conversion table T is configured to be smaller than the proportional change rate of A. In the present embodiment, the proportional change rate of the conversion ratio A in the fourth table T4 on the side where the detected value X is larger is smaller than the proportional change rate of the conversion ratio A in the second table T2 on the side where the detected value X is smaller. Thereby, the relationship between the detection value X and the yield value V in the detection range of the fourth table T4 approaches the linear proportional relationship as much as possible.

The concept of the conversion table T is applied to the calculation of the total weight of kernels by the weight sensor 40 shown in FIG. For example, when grains start to be concentrated in a part of the grain tank 7 due to factors such as the shape of the grain tank 7, the detection value of the weight sensor 40 for detecting the total weight, and the actual grain There is a possibility that the total weight of and may not be in linear proportion. In such a case, the yield conversion unit 32 selects one conversion table selected from a plurality of conversion tables having different conversion ratios according to the magnitude of the detection value of the weight sensor 40 based on the same idea as the conversion table T. To convert the detected value of the weight sensor 40 into a yield value.

[Another embodiment]
The present invention is not limited to the configuration exemplified in the above-described embodiment, and hereinafter, another representative embodiment of the present invention will be illustrated.

(1) In the embodiment described above, five conversion tables T are stored in the storage unit 33, but the present invention is not limited to this embodiment, and the number of tables may be two or more. For example, among the two conversion tables, the conversion ratio A in one conversion table may be a constant value, and the conversion ratio A in the other conversion table may change in proportion. At this time, when the conversion table is switched due to the change of the detection value X, the conversion ratio A may not be stepless but may change stepwise.

(2) In the embodiment described above, the conversion table T is configured by a plurality of conversion tables, but is not limited to this embodiment. For example, as shown in FIG. 9, one conversion table T may be configured by a plurality of sub-tables, and only one conversion table T may be stored in the storage unit 33.

(3) In the embodiment described above, the first threshold X1, the second threshold X2, the third threshold X3, and the fourth threshold X4 correspond to the second table T2, the third table T3, the fourth table T4, and the fifth table T5. The lower limit value of the detection value X is set, but to which conversion table the values of the first threshold value X1, the second threshold value X2, the third threshold value X3, and the fourth threshold value X4 belong can be determined appropriately. For example, the first threshold X1, the second threshold X2, the third threshold X3, and the fourth threshold X4 are upper limit values of the detection value X in the first table T1, the second table T2, the third table T3, and the fourth table T4. It may be set. It is also possible to set two thresholds in one conversion table T. For example, when the detected value X is equal to or greater than the first threshold X1 and equal to or less than the second threshold X2, the yield conversion unit 32 may be configured to select the second table T2, and the detected value X may The yield conversion unit 32 may be configured to select the fourth table T4 when the third threshold X3 or more and the fourth threshold X4 or less.

(4) The invention is not limited to the above-described embodiment, and the conversion ratios A of all the conversion tables T may be configured with a constant value. In this case, even if the conversion ratios A of the conversion tables T are different values, a large number of conversion tables T designated in a small detection range are arranged so that the change in the conversion ratio A becomes small. The configuration may be such that the yield value V changes in small steps.

(5) In the embodiment described above, the plurality of conversion tables T are configured such that the value of the conversion ratio A falls to the right as the detected value X increases, but the present invention is not limited to this embodiment. . For example, the plurality of conversion tables T may be configured such that the value of the conversion ratio A increases as the detected value X increases.

(6) By associating the yield value V with the GPS position information, the yield value V can be used for the distribution of the yield for each minute section of the field. In addition, if there is an error between the integrated value of the yield value V and the yield value calculated from the detection value of the weight sensor 40, each of the past yield values V can be corrected according to the error. .

(7) In the embodiment described above, the detection plate 20A and the load cell 20B are provided in the yield sensor 20 via the spacer 20C, but the yield sensor 20 detects the grain yield only by the load cell 20B. It may be of such a configuration. Also, the configuration may be such that the yield of grain is detected by a strain gauge sensor instead of the load cell 20B.

(8) The conversion table T is not limited to the embodiment described above, and can be applied to a yield sensor configured as follows. For example, as shown in FIG. 10, the configuration is also applicable to a configuration in which the outlet 102 is formed in the sidewall 100 of the grain tank and the yield sensor 104 is disposed adjacent to the outlet 102. In this example, a throwing plate 103 that rotates integrally with the screw conveyor 101 is provided at the upper end of the screw conveyor 101 that rotates in the direction of arrow R to vertically transport the grain from the bottom of the threshing apparatus. The grain is splashed from the outlet 102 by the throwing plate 103 and the pressure of the grain is detected by the yield sensor 104. That is, the yield sensor 104 is provided with a detection plate 104A and a load cell 104B, and the load cell 104B detects the pressing force of the grain applied to the detection plate 104A.

(9) In the embodiment described above, the weight sensor 40 is provided at the front lower end of the grain tank 7, but the weight sensor 40 may not be provided.

(10) In the embodiment mentioned above, although a common type combine was illustrated as a harvest machine, it is applicable also to the whole harvest machine which harvests grain, such as a self-removal side combine.

6: threshing device 7: grain tank 10: grain conveyance route 11: grain discharging device 12: discharge rotating body 13: discharge case 14: load cell 20: yield sensor 31: input signal processing unit 32: yield conversion unit 33: Storage part T: Conversion table X: Detection value A: Conversion ratio V: Yield value

Claims

A threshing device,
A grain tank for storing grains collected by the threshing device;
A grain transfer path for transferring grains from the threshing device to the grain tank;
A yield sensor for detecting pressure based on the amount of grain passing through the grain transport path;
A yield conversion unit configured to convert a detected value detected by the yield sensor into a yield value representing a yield;
A storage unit storing a plurality of conversion tables having different conversion ratios for converting the detected value into the yield value;
The yield conversion unit selects one conversion table from the plurality of conversion tables according to the magnitude of the detection value when converting the detection value, and is a harvester.
The harvester according to claim 1, wherein the conversion table selects a conversion table having a smaller conversion ratio as the detected value is larger, and selects a conversion table having a larger conversion ratio as the detected value is smaller. .
In the storage unit, as the plurality of conversion tables, a first table used when the detected value is smaller than a first threshold, and a second threshold larger than the first threshold and the first threshold. And a third table used when the detected value is larger than the second threshold, and a second table used when
The conversion ratio in the first table is a constant value,
The conversion ratio in the third table is a constant value different from the conversion ratio of the first table,
The conversion ratio in the second table is proportionally changed according to the detection value so as to linearly complement the conversion ratio of the first table and the conversion ratio of the third table. Harvester described in.
A fourth table used as the plurality of conversion tables in the storage unit when the detected value is between a third threshold larger than the second threshold and a fourth threshold larger than the third threshold; A fifth table used when the detected value is larger than the fourth threshold is stored,
The conversion ratio in the fifth table is a fixed value of a value different from the conversion ratio of the first table and the conversion ratio of the third table,
The conversion ratio in the fourth table changes in proportion to the detected value so as to linearly complement the conversion ratio of the third table and the conversion ratio of the fifth table,
The harvester according to claim 3, wherein a proportional change rate of the conversion ratio in the second table is larger than a proportional change rate of the conversion ratio in the fourth table.