JP7728629B2 - Moisture Measurement System - Google Patents

Description

The present invention relates to a moisture measurement system that measures the moisture content of grains.

In a combine harvester, crops planted in the field are harvested by a harvesting device, and the harvested crops are transported from the harvesting device to a thresher, where the grains are removed from the stalks, sorted, and transported to a grain tank.

Some combine harvesters are equipped with a moisture sensor (moisture meter) in the grain tank that measures the moisture content of the grain. The moisture sensor is positioned so that it can receive the grain discharged from the discharge section. The moisture sensor is, for example, an electrical resistance type moisture sensor equipped with a pair of electrode rollers. The grain received in the moisture sensor is caught between the pair of electrode rollers as they rotate, and is crushed between the electrode rollers. With the crushed grain sandwiched between the electrode rollers, the electrical resistance between the electrode rollers is measured, and the moisture content of the grain is determined from this electrical resistance value (see, for example, Patent Document 1).

Patent No. 6451513

However, configurations using electrical resistance moisture sensors have the problem of low moisture measurement accuracy.

The object of the present invention is to provide a moisture measurement system that can accurately measure the moisture content of grains.

To achieve the above-mentioned objective, the moisture content measurement system of the present invention includes a moisture sensor that crushes grains between a pair of electrode rollers by rotating them and outputs a signal corresponding to the electrical resistance between the electrode rollers when the grains are crushed; a control device that receives the signal output from the moisture sensor, determines a sensor output value from the received signal, and determines the moisture content corresponding to the sensor output value from a calibration curve; and an input device that inputs the reference moisture content of the grains into the control device. The reference moisture content is a measured value of the moisture content of grains estimated to contain the same moisture content as the grains crushed by the moisture sensor, measured by a device other than the control device. The control device determines a value corresponding to the reference moisture content from the calibration curve, and corrects the sensor output value using the deviation between the determined value and the sensor output value as a correction value.

With this configuration, the moisture sensor crushes grains between a pair of electrode rollers as they rotate. Then, with the crushed grains (crushed grains) sandwiched between the electrode rollers, the moisture sensor outputs a signal to the control device that corresponds to the electrical resistance between the electrode rollers. The control device calculates the sensor output value from the signal received from the moisture sensor, and then uses the calibration curve to determine the moisture content corresponding to the sensor output value.

The control device also receives input of the reference moisture content of the grains via an input device. The reference moisture content is a measurement of the moisture content of grains estimated to contain the same moisture content as the grains crushed by the moisture sensor, measured by equipment other than the control device. The control device obtains a value corresponding to the reference moisture content from the calibration curve, and the deviation between this value and the sensor output value is used as a correction value to correct the sensor output value.

The deviation between the value corresponding to the reference moisture content obtained from the calibration curve and the sensor output value is an error caused by the characteristics of the moisture sensor. By correcting the sensor output value using this deviation as a correction value, the error can be eliminated from the sensor output value. As a result, the moisture content in the grain can be measured with high accuracy by determining the moisture content corresponding to the corrected sensor output value from the calibration curve.

Grains estimated to contain the same moisture content as the grains crushed with the moisture sensor may be grains harvested from the same field plot as the grains crushed with the moisture sensor.

The input device may be a meter panel installed on the combine that displays information.

The moisture content measurement system may further include a communication unit that communicates with an external device, and the input device may be the external device. The external device may be a terminal or a server.

The server may also receive the moisture content of the grains measured by the dryer that dries the grains. In this case, it is preferable that the server inputs the moisture content received from the dryer as the reference moisture content into the control device via the communication unit.

In this configuration, the reference moisture content is automatically entered into the control device without the need to operate the meter panel, terminal, or server.

This invention makes it possible to accurately measure the moisture content of grains.

1 is a right side view of a combine harvester equipped with a moisture content measuring device according to an embodiment of the present invention. FIG. 1 is a perspective view of the upper left portion of the grain tank from the rear right, with the top plate of the grain tank removed. FIG. 1 is a front view of the grain tank. FIG. 1 is a front view of the grain tank with the cover removed. FIG. 10 is a rear view of the moisture sensor. FIG. 2 is a block diagram showing the main parts of the electrical configuration of the combine harvester. 10 is a flowchart showing the flow of a measurement method selection process. FIG. 10 is a diagram illustrating the contents of a first measurement method. FIG. 10 is a diagram illustrating the contents of a second measurement method. FIG. 10 is a diagram for explaining a method for correcting a sensor output value. FIG. 10 is a block diagram showing a modified example of the electrical configuration of the combine harvester.

The following describes in detail an embodiment of the present invention with reference to the accompanying drawings.

<Overall configuration of the combine>
FIG. 1 is a right side view of a combine harvester 1 on which a moisture content measuring device according to one embodiment of the present invention is mounted.

The combine harvester 1 is an agricultural machine that harvests and threshes crops while traveling through a field.

The combine harvester 1 employs a pair of left and right crawler traveling devices 2 as traveling devices capable of traveling over uneven terrain such as farm fields. A machine frame 3 is supported by the left and right crawler traveling devices 2, and power from an engine mounted on the machine frame 3 is transmitted to the crawler traveling devices 2 via a transmission.

Also mounted on the machine frame 3 are a cabin 4, a threshing device 5, and a grain tank 6. A harvesting device 7 for harvesting crops is provided in front of the crawler travelling device 2 and the machine frame 3.

The cabin 4 is located on the front end of the aircraft frame 3. The cabin 4 provides a space for the user to board, and within this space are located, for example, a driver's seat where the user sits, operating levers that the user operates, and the like. An openable door 8 is provided on the right side of the cabin 4, and the user can open the door 8 to enter the cabin 4.

The threshing device 5 is located to the rear left of the cabin 4. The grain tank 6 is located behind the cabin 4 and to the right of the threshing device 5. In the threshing device 5, the material to be sorted obtained by threshing the crop is sorted and collected. The collected material to be sorted (grains) is transported to the grain tank 6 and stored therein. An unloader 9 is connected to the grain tank 6, and the grain stored in the grain tank 6 can be discharged from the grain tank 6 to the outside of the machine by the unloader 9.

<Main components of the grain tank>
FIG. 2 is a perspective view of the upper left portion of the grain tank 6 as seen from the right rear, with the top plate of the grain tank 6 removed.

A discharge section 12 is provided inside the grain tank 6, at the top of the left side wall 11 of the grain tank 6, in the center in the front-to-rear direction. Although not shown, the discharge section 12 is equipped with rotating blades that rotate around an axis extending in the vertical direction. Grains are transported from the threshing device 5 to the discharge section 12, swept away by the rotating blades, and ejected from the discharge section 12 toward the front right.

A sensor housing 14 that bulges into the grain tank 6 is formed on the front wall 13 of the grain tank 6. The sensor housing 14 houses a moisture sensor 15.

Figures 3 and 4 are front views of the grain tank 6.

As shown in FIG. 4, the sensor housing 14 includes an upper inclined plate 16 that slopes downward toward the rear from the upper end of the front wall 13, a rear plate 17 that extends downward from the rear edge of the upper inclined plate 16, a lower inclined plate 18 that slopes downward toward the front from the lower edge of the rear plate 17 toward the lower end of the front wall 13, and side plates 19 that close the space surrounded by the upper inclined plate 16, rear plate 17, and lower inclined plate 18 from the left and right. The sensor housing 14 provides the space defined by the upper inclined plate 16, rear plate 17, lower inclined plate 18, and side plates 19 as a sensor housing space 21 in which the moisture sensor 15 is housed.

As shown in FIG. 3, a cover 22 is attached to the front surface of the front wall 13 of the grain tank 6 to close the sensor accommodating space 21. In FIG. 4, the cover 22 has been removed from the front wall 13. The vertical dimension of the cover 22 is shorter than the vertical distance between the front edge of the upper inclined plate 16 and the front edge of the lower inclined plate 18. With the cover 22 attached to the front surface of the front wall 13, gaps 23 and 24 are formed between the front edge of the upper inclined plate 16 and the upper edge of the cover 22, and between the front edge of the lower inclined plate 18 and the lower edge of the cover 22, respectively. This allows heat to escape from the sensor accommodating space 21 through the gaps 23 and 24. Furthermore, even if water enters the sensor accommodating space 21 from the outside, the water can be drained from the sensor accommodating space 21 through the gap 24. Furthermore, because the lower inclined plate 18 is tilted downward toward the front, water is prevented from accumulating on the lower inclined plate 18.

However, if a gap 23 is formed between the front edge of the upper inclined plate 16 and the upper edge of the cover 22, there is a risk that when high-pressure water is sprayed toward the gap 23, the water may enter the sensor housing space 21 through the gap 23. To prevent water that has entered the sensor housing space 21 through the gap 23 from contacting the moisture sensor 15, a shield 25 is attached to the upper inclined plate 16, as shown in Figure 4. The shield 25 integrally includes a rectangular plate-shaped contact portion 26 that contacts the upper inclined plate 16 and a rectangular plate-shaped water-blocking portion 27 that extends downward from the contact portion 26. The contact portion 26 is fixed to the upper inclined plate 16 by welding.

Figure 5 shows the moisture sensor 15 from the rear.

The moisture sensor 15 includes a box-shaped sensor case 31. A receiving opening 32 for receiving grains into the sensor case 31 is formed on the rear surface of the sensor case 31. The receiving opening 32 is symmetrical and has a V-shaped lower side 33 that opens upward, a first left side 34 that extends upward from the upper left end of the lower side 33 and is inclined at a relatively small angle to the left in the vertical direction (the vertical direction), a second left side 35 that extends upward from the upper end of the first left side 34 and is inclined at a relatively large angle to the left in the vertical direction, a first right side 36 that extends upward from the upper right end of the lower side 33 and is inclined at a relatively small angle to the right in the vertical direction, and a second right side 37 that extends upward from the upper end of the first right side 36 and is inclined at a relatively large angle to the right in the vertical direction. A flat surface extends forward from each of the first left side 34, second left side 35, first right side 36, and second right side 37, and these flat surfaces function as guide surfaces that guide kernels into the sensor case 31.

A pair of electrode rollers 41, 42 are provided in the roller storage space behind the receiving port 32 within the sensor case 31. The electrode rollers 41, 42 are integrally formed with roller shafts 43, 44, which extend parallel to each other in the front-to-rear direction. The peripheral surfaces of the electrode rollers 41, 42 are closely spaced in the left-to-right direction. A gap corresponding to the size of the rice (husks) is provided between the peripheral surfaces of the electrode rollers 41 and 42, a gap slightly smaller than the width of the rice (length perpendicular to the longitudinal direction). Numerous minute irregularities are formed on the peripheral surfaces of the electrode rollers 41, 42.

A motor 45 (see Figure 6) is provided inside the sensor case 31, and the power of the motor 45 causes the pair of electrode rollers 41, 42 to rotate forward and reverse. When the electrode rollers 41, 42 rotate forward, the left electrode roller 41 rotates clockwise and the right electrode roller 42 rotates counterclockwise, as viewed from inside the grain tank 6. When the electrode rollers 41, 42 rotate reversely, the left electrode roller 41 rotates counterclockwise and the right electrode roller 42 rotates clockwise, as viewed from inside the grain tank 6.

A guide member 46 is attached to the inner surface of the front wall 13. The guide member 46 is shaped like a flat plate bent into a V-shape, with the fold line positioned lower toward the front and its front end (lower end) positioned on a plane extending forward from the lower edge 33 of the receiving opening 32 of the sensor case 31.

Some of the grains scattered from the discharge section 12 inside the grain tank 6 reach the position of the sensor case 31 and are directly received into the sensor case 31 through the receiving port 32 of the sensor case 31. Furthermore, grains that reach the guide member 46 flow along the guide member 46 toward the sensor case 31, drop from the guide member 46, and are received into the sensor case 31 through the receiving port 32. The grains received into the sensor case 31 through the receiving port 32 accumulate on the electrode rollers 41, 42. When the electrode rollers 41, 42 rotate forward, the grains are sandwiched between the electrode rollers 41, 42 and crushed.

In addition, when the electrode rollers 41 and 42 rotate in the reverse direction, a brush (not shown) comes into contact with each peripheral surface of the electrode rollers 41 and 42, cleaning the peripheral surfaces (surfaces) of the electrode rollers 41 and 42.

The roller storage space that houses the electrode rollers 41, 42 has an open bottom. Therefore, grains received into the sensor case 31 through the receiving opening 32 and crushed grains scraped off the periphery of the electrode rollers 41, 42 do not accumulate in the roller storage space except on the electrode rollers 41, 42. Instead, they are discharged from the roller storage space into the grain tank 6 through the return passage 47 located below the moisture sensor 15.

<Electrical configuration of combine>
FIG. 6 is a block diagram showing the main parts of the electrical configuration of the combine harvester 1.

The combine harvester 1 is equipped with an ECU (Electronic Control Unit) 51. The ECU 51 has a microcontroller (microcomputer), which includes, for example, a CPU, non-volatile memory such as flash memory, and volatile memory such as DRAM (Dynamic Random Access Memory).

The ECU 51 has functional processing units for measuring the moisture content of the grain stored in the grain tank 6, including a measurement method switching unit 52, a measurement processing unit 53, a sensor output value acquisition unit 54, and a sensor output value correction unit 55. These functional processing units are realized in software through program processing, by hardware such as a logic circuit, or by a combination of these.

The measurement method switching unit 52 switches between the measurement methods for measuring the moisture content of grains, in other words, the method for controlling the operation of the moisture sensor 15 to measure the moisture content of grains. Specifically, two measurement methods, a first measurement method and a second measurement method, are provided for measuring the moisture content of grains. The measurement method switching unit 52 switches between the first measurement method and the second measurement method for measuring the moisture content of a crop (type of grain) set as the target for moisture measurement.

The measurement processing unit 53 controls the motor 45 of the moisture sensor 15 according to the first or second measurement method set by the measurement method switching unit 52, switching between forward, reverse, and stopped rotation of the electrode rollers 41, 42, and switching between supplying and stopping a constant voltage between the electrode rollers 41, 42.

The sensor output value acquisition unit 54 receives an output signal from the signal output circuit 56 provided in the moisture sensor 15. When the electrode rollers 41, 42 rotate forward to crush grains between them, a constant voltage is supplied between them, and the signal output circuit 56 outputs a signal with a voltage value corresponding to the electrical resistance between them. The smaller the electrical resistance between the electrode rollers 41, 42, the larger the signal value output from the signal output circuit 56. The sensor output value acquisition unit 54 performs an averaging process to average the signal values input from the signal output circuit 56 to determine the sensor output value. The averaging process is performed according to the crop set as the target for moisture content measurement.

The sensor output value correction unit 55 corrects the sensor output value acquired by the sensor output value acquisition unit 54.

A calibration curve 57 showing the relationship between the sensor output value and moisture content is stored in the non-volatile memory of the ECU 51. The ECU 51 uses the calibration curve 57 to determine the moisture content corresponding to the sensor output value corrected by the sensor output value correction unit 55, and the determined moisture content is used as the moisture content of the grain stored in the grain tank 6.

In addition, a meter panel 58 is disposed within the cabin 4 in a position where it can be seen and operated by a user seated in the driver's seat. The meter panel 58 is composed of a touch panel configured, for example, by overlaying pressure-sensitive or capacitance-type transparent film switches on a display such as an LCD. Images of various information and operation buttons are displayed on the meter panel 58. When the user touches an operation button, an instruction corresponding to the type of operation button touched is received by the meter panel 58. When the instruction is received by the meter panel 58, a signal corresponding to the content of the instruction is input from the meter panel 58 to the ECU 51. The user can also input numerical values by touching the meter panel 58. When a numerical value is input, a signal corresponding to the input numerical value is input from the meter panel 58 to the ECU 51.

The settings required for processing by the measurement method switching unit 52 and the sensor output value acquisition unit 54, i.e., the setting of the crop to be measured for moisture content, can be made by touching the meter panel 58. The meter panel 58 also allows the setting of the crop to be worked by the implements mounted on the combine harvester 1, i.e., the threshing unit 5 and the reaping unit 7. The crops worked by the threshing unit 5 and the reaping unit 7 and the crop for which moisture content is measured are the same, so when one of these is set, the settings are reflected in the other settings. For example, when the crop to be worked by the threshing unit 5 is set, the crop to be worked by the reaping unit 7 is also set to the same crop, and the crop for which moisture content is measured is also set to the same crop.

Furthermore, by touching the meter panel 58, the reference moisture content required for the sensor output value correction unit 55 to correct the sensor output value can be input.

<Measurement method selection process>
FIG. 7 is a flowchart showing the flow of the measurement method selection process.

For example, when the combine harvester 1 starts harvesting crops, the measurement method switching unit 52 of the ECU 51 executes a measurement method selection process to switch the measurement method for measuring the moisture content of grains depending on the crop.

In the measurement method selection process, it is determined whether the target crop has been set for the work implements (thresher 5, harvester 7) mounted on the combine harvester 1 (step S1).

If a crop has already been set for the work device (YES in step S1), that setting is also reflected in the setting for the crop to be measured for moisture content, so the measurement method corresponding to the set crop is selected from the first measurement method and the second measurement method (step S2), and the measurement method selection process is terminated.

When the crop to be measured for moisture content is set to rice or wheat, the first measurement method is selected as the measurement method for measuring the moisture content of the grain. On the other hand, when the crop to be measured for moisture content is set to barley, the second measurement method is selected as the measurement method for measuring the moisture content of the grain. The details of the first and second measurement methods will be described later.

If a crop has not been set for the work device (NO in step S1), a determination is made as to whether a crop for which moisture content is to be measured has been set (step S3).

When the crop to be measured for moisture content is set (step S3), the measurement method corresponding to the set crop is selected from two methods, the first measurement method and the second measurement method (step S2), and the measurement method selection process is terminated.

If a crop to be measured for moisture content has not been set even after a predetermined time has elapsed since the start of the measurement method selection process (NO in step S3), a default measurement method, for example, the first measurement method, is selected (step S4), and the measurement method selection process is terminated.

Figure 8 shows the details of the first measurement method.

As mentioned above, when the crop to be measured for moisture content is set to rice or wheat, the first measurement method is selected as the measurement method for measuring the moisture content of the grain. When measuring moisture content using the first measurement method, the measurement processing unit 53 controls the operation of the moisture sensor 15 in accordance with the first measurement method.

In this control, the electrode rollers 41, 42 are stopped and kept on standby for a first period of time (e.g., 90 seconds) after grains start to be discharged from the discharge section 12 into the grain tank 6 until grains are stored in the sensor case 31 of the moisture sensor 15.

After the first time period has elapsed, the motor 45 is driven in the forward direction, causing the electrode rollers 41, 42 to rotate in the forward direction. As the electrode rollers 41, 42 rotate in the forward direction, the grains are sandwiched between the electrode rollers 41, 42 and crushed. While the electrode rollers 41, 42 are rotating in the forward direction, a constant voltage is applied between the electrode rollers 41, 42, and the signal output circuit 56 outputs a signal with a voltage value corresponding to the electrical resistance between the electrode rollers 41, 42. The forward rotation of the electrode rollers 41, 42 and the application of the constant voltage between the electrode rollers 41, 42 continue for a second time period (e.g., 10 seconds).

When a second time has elapsed since the electrode rollers 41, 42 began rotating forward and voltage was applied between them, the motor 45 is stopped and then driven in the reverse direction. The reverse rotation of the motor 45 rotates the electrode rollers 41, 42 in the reverse direction, cleaning the circumferential surfaces of the electrode rollers 41, 42. When the reverse rotation of the motor 45 continues for a third time, the motor 45 is stopped, and control of the operation of the moisture sensor 15 using the first measurement method for measuring the moisture content of grain is terminated.

Because there is a gap between the circumferential surfaces of electrode roller 41 and electrode roller 42 that corresponds to the size of the rice, small grains such as rice or wheat can easily get caught between electrode rollers 41 and 42. Therefore, when electrode rollers 41 and 42 rotate in the forward direction, grains on electrode rollers 41 and 42 are continuously caught between electrode rollers 41 and 42 and crushed. Therefore, there is little fluctuation in the signal value output from signal output circuit 56 of moisture sensor 15 from the time the signal value rises until the grains disappear from electrode rollers 41 and 42.

Taking these characteristics into consideration, when the crop set for moisture content measurement is rice or wheat and the operation of the moisture sensor 15 is controlled according to the first measurement method, the averaging process involves the sensor output value acquisition unit 54 sampling the signal values input from the signal output circuit 56 to the sensor output value acquisition unit 54 at a predetermined sampling period during a predetermined period while the electrode rollers 41, 42 are rotating forward. The average value and standard deviation are then calculated from the sampled values, and the standard deviation is multiplied by a constant and added to the average value to calculate an average value of the signal values output from the signal output circuit 56, which is then used as the sensor output value.

Figure 9 shows the details of the second measurement method.

When barley is set as the crop to be measured for moisture content, the second measurement method is selected as the measurement method for measuring the moisture content of the grain. When measuring moisture content using the second measurement method, the measurement processing unit 53 controls the operation of the moisture sensor 15 in accordance with the second measurement method.

In this control, the electrode rollers 41, 42 are kept stopped and wait for a fourth time (e.g., 40 to 50 seconds) from when the discharge section 12 starts discharging grains into the grain tank 6 until grains are stored in the sensor case 31 of the moisture sensor 15.

After the fourth time has elapsed, the motor 45 is driven in the forward direction, causing the electrode rollers 41, 42 to rotate in the forward direction. As the electrode rollers 41, 42 rotate in the forward direction, the grains are sandwiched between the electrode rollers 41, 42 and crushed. While the electrode rollers 41, 42 are rotating in the forward direction, a constant voltage is applied between the electrode rollers 41, 42, and the signal output circuit 56 outputs a signal with a voltage value corresponding to the electrical resistance between the electrode rollers 41, 42. The forward rotation of the electrode rollers 41, 42 and the application of the constant voltage between the electrode rollers 41, 42 continue for a fifth time (e.g., 3 seconds), which is shorter than the second time.

When the fifth time has elapsed since the electrode rollers 41, 42 began rotating forward and voltage was applied between them, the motor 45 is stopped and then driven in the reverse direction. Driving the motor 45 in the reverse direction causes the electrode rollers 41, 42 to rotate in the reverse direction, cleaning the circumferential surfaces of the electrode rollers 41, 42. When the reverse driving of the motor 45 continues for a sixth time (e.g., three seconds), the motor 45 is stopped and then driven in the forward direction. Driving the motor 45 in the forward direction causes the electrode rollers 41, 42 to rotate forward. At this time, no voltage is applied between the electrode rollers 41, 42. When the forward driving of the motor 45 continues for a seventh time (e.g., two seconds), the motor 45 is stopped.

When motor 45 stops, electrode rollers 41 and 42 stop, and grains are accumulated in sensor case 31. After an eighth time (e.g., seven seconds) has elapsed since motor 45 stopped, the following cycle is repeated eight times (loop): motor 45 rotates forward (electrode rollers 41 and 42 rotate forward) and voltage is applied between electrode rollers 41 and 42 for a fifth time, motor 45 rotates reversely for a sixth time, motor 45 rotates forward for a seventh time, and motor 45 is stopped for an eighth time.

Then, when the motor 45 is stopped for the ninth time for eight hours, the motor 45 is driven in the forward direction, causing the electrode rollers 41, 42 to rotate in the forward direction and applying voltage between the electrode rollers 41, 42 for five hours. After that, when the motor 45 continues to be driven in the reverse direction for a sixth hour, the motor 45 is stopped once and then driven in the forward direction. At this time, no voltage is applied between the electrode rollers 41, 42. When the motor 45 continues to be driven in the forward direction for a seventh hour, the motor 45 is stopped, and control of the operation of the moisture sensor 15 using the second measurement method for measuring the moisture content of grain is terminated.

Compared to rice or wheat, barley is less likely to enter between the electrode rollers 41 and 42. If a grain that is difficult to enter between the electrode rollers 41 and 42 is set as the target for moisture content measurement, there may be a period during which the signal value output from the moisture sensor is extremely small, as the grain does not enter between the electrode rollers 41 and 42 while the electrode rollers 41 and 42 are rotating forward, and this period may continue for a long time.

Therefore, when the crop set to be measured for moisture content is barley, a measurement period (fifth time) is set that is shorter than the measurement period (second time) during which the electrode rollers 41, 42 are rotated forward and a constant voltage is applied between the electrode rollers 41, 42 using the first measurement method, and the sensor output value is determined from the value of the signal input from the signal output circuit 56 to the sensor output value acquisition unit 54 during that measurement period.

In other words, in the averaging process when the operation of the moisture sensor 15 is controlled according to the second measurement method, the sensor output value acquisition unit 54 acquires the peak values of the signal input from the signal output circuit 56 to the sensor output value acquisition unit 54 over a total of 10 measurement periods. Then, the average of the acquired 10 peak values is calculated, and this average is used as the sensor output value.

<Sensor output value correction>
In order for the sensor output value correcting unit 55 to correct the sensor output value acquired by the sensor output value acquiring unit 54, a reference moisture content must be input. The reference moisture content is a value measured by a device other than the combine harvester 1 and estimated to contain the same moisture content as the grains crushed by the moisture sensor 15 when the sensor output value is acquired. An example of grains estimated to contain the same moisture content as the grains crushed by the moisture sensor 15 is grains harvested from the same field as the grains crushed by the moisture sensor 15. The moisture content of grains harvested from the same field as the grains crushed by the moisture sensor 15 can be measured using a moisture meter or a grain drying machine owned by the user, and the measured moisture content can be used as the reference moisture content. In this embodiment, the reference moisture content can be input by touching the meter panel 58.

Figure 10 is a diagram explaining the method for correcting sensor output values.

When the reference moisture content for the sensor output value (combine measurement value) acquired by the sensor output value acquisition unit 54 is input, the sensor output value correction unit 55 calculates the sensor output value corresponding to the reference moisture content using the calibration curve 57 stored in the non-volatile memory of the ECU 51. The deviation between the sensor output value corresponding to the reference moisture content and the sensor output value acquired by the sensor output value acquisition unit 54 is then calculated as a correction value, and this correction value is stored in the volatile memory of the ECU 51.

After that, when the sensor output value is acquired by the sensor output value acquisition unit 54, the sensor output value is corrected using the correction value, and the moisture content corresponding to the corrected sensor output value is obtained from the calibration curve 57.

The sensor output values may be corrected each time they are acquired, or they may be temporarily stored in non-volatile memory and then all sensor output values may be corrected at once later.

<Action and effect>
As described above, when the crop to be measured for moisture content is set to rice or wheat, the first measurement method is selected as the measurement method for measuring the moisture content of the grain, and the operation of the moisture sensor 15 is controlled in accordance with the second measurement method. On the other hand, when the crop to be measured for moisture content is set to barley, the second measurement method is selected as the measurement method for measuring the moisture content of the grain, and the operation of the moisture sensor 15 is controlled in accordance with the second measurement method. This makes it possible to determine a sensor output value corresponding to the size of the grain from the output signal of the moisture sensor 15, and to determine the moisture content corresponding to that sensor output. Therefore, the moisture content of the grain can be measured with high accuracy.

In addition, a calibration curve 57 stored in the non-volatile memory of the ECU 51 is used to determine the sensor output value corresponding to the reference moisture content input by touching the meter panel 58. The deviation between the sensor output value corresponding to the reference moisture content and the sensor output value acquired by the sensor output value acquisition unit 54 is then determined as a correction value. The deviation between the sensor output value corresponding to the reference moisture content determined from the calibration curve 57 and the sensor output value acquired by the sensor output value acquisition unit 54 is an error arising from the characteristics of the moisture sensor 15, and by correcting the sensor output value using this deviation as a correction value, the error can be eliminated from the sensor output value. As a result, the moisture content of the grain can be measured more accurately by determining the moisture content corresponding to the corrected sensor output value from the calibration curve 57.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

For example, as shown in FIG. 11, a communication unit 61 may be provided that communicatively connects the ECU 51 to an external device, and the settings for the crop to be measured for moisture content may be transmitted to the ECU 51 from an external device such as a server 62 or terminal 63. The reference moisture content may also be transmitted from the server 62 or terminal 63 to the ECU 51. If the operation of a dryer 64 that dries grains is managed by the server 62, the moisture content of the grains measured by the dryer 64 may be transmitted from the dryer 64 to the server 62, and the moisture content of the grains measured by the dryer 64 may then be transmitted from the server 62 to the ECU 51 as the reference moisture content.

In addition, in the above-described embodiment, when the crop to be measured for moisture content is set to rice or wheat, the first measurement method is selected as the measurement method for measuring the moisture content of the grain, and when the crop to be measured for moisture content is set to barley, the second measurement method is selected as the measurement method for measuring the moisture content of the grain. However, this is not limited to this; when the crop to be measured for moisture content is set to small grains such as rice or wheat, the first measurement method may be selected as the measurement method for measuring the moisture content of the grain, and when the crop to be measured for moisture content is set to large grains such as barley, the second measurement method may be selected as the measurement method for measuring the moisture content of the grain.

In addition, various design modifications may be made to the above-described configuration within the scope of the claims.

1: Combine harvester 15: Moisture sensor 41: Electrode roller 42: Electrode roller 51: ECU (control unit)
57: Calibration curve 58: Meter panel (input device)
61: Communication unit 62: Server (input device)
63: Terminal (input device)
64: Dryer

Claims (7)

a moisture sensor that crushes grains between a pair of electrode rollers by rotating the electrode rollers and outputs a signal corresponding to the electrical resistance value between the electrode rollers when the grains are being crushed;
a control device that receives a signal output from the moisture sensor, determines a sensor output value from the received signal, and determines the moisture content corresponding to the sensor output value from a calibration curve;
an input device for inputting a reference moisture content of grains into the control device;
The reference moisture content is a measured value of the moisture content of grains estimated to contain the same moisture content as the grains crushed by the moisture sensor, measured by an instrument other than the control device,
The control device determines a value corresponding to the reference moisture content from the calibration curve, and corrects the sensor output value using the deviation between the determined value and the sensor output value as a correction value. The moisture content measurement system of claim 1, wherein the grains estimated to contain the same moisture content as the grains crushed by the moisture sensor are grains harvested from the same plot of land in a field as the grains crushed by the moisture sensor. The moisture content measurement system of claim 1, wherein the input device is a meter panel provided on a combine harvester that displays information. a communication unit for communicating with an external device,
The moisture content measurement system according to claim 1 , wherein the input device is the external device. The moisture content measurement system of claim 4, wherein the external device is a terminal. The moisture content measurement system of claim 4, wherein the external device is a server. The moisture content of the grains measured by a dryer that dries the grains is transmitted to the server,
The moisture amount measuring system according to claim 6 , wherein the server inputs the moisture amount received from the dryer as the reference moisture amount to the control device via the communication unit.