CN201657632U - Combine Harvester Grain Cleaning Loss Intelligent Online Detection Device - Google Patents

Abstract

The utility model discloses an intelligent online detection device for grain cleaning loss of a combine harvester in agricultural machinery. The output of an array piezoelectric crystal sensor is connected to a charge amplifier, and the output of the charge amplifier is sequentially connected in series with a gain-adjustable circuit and a high-pass filter circuit. , sensitivity adjustment circuit, pulse shaping circuit, single-chip microprocessor and communication interface circuit; the sensor plate sensitive element of the array piezoelectric crystal sensor is 40°-60° from the horizontal position, and its two ends are adjustable and fixedly connected to the joint On the fixed bracket at the rear of the cleaning screen of the harvester, the piezoelectric detection array is applied to the back of the flat sensor element of the sensor and sealed. Sorting loss, ingesting information from multiple regions and multiple angles, enhancing the impact signal of grains, improving the recognition accuracy and testing reliability of grain and grass; the overall dynamic performance is good, the anti-interference ability is strong, and the field online measurement of cleaning loss is realized.

Description

Combine harvester grain cleaning loss intelligent online detection device

technical field

The utility model relates to a combine harvester among agricultural machinery, in particular to a device for intelligently detecting the grain cleaning loss of the combine harvester. the

Background technique

In the performance test of the combine harvester, the grain cleaning loss rate is an important index, which directly affects the production efficiency and operation quality of the harvester. In grain harvesting operations, when the moisture content of the stalks is low, a large number of broken stalks produced during the threshing process will increase the cleaning load, reduce the cleaning quality, and the cleaning loss rate is as high as about 4%, which greatly reduces the operating cost. quality. For a long time, the detection of this index has been using manual counting and manual calculation of the loss rate. The disadvantages are: low work efficiency, large errors, and inability to guide the harvesting operation of the unit in real time. the

Since there are very few grains in the sieve throws compared to the stalks and grass, the grain loss signal detected by the sensor is very weak, almost drowned in the strong vibration noise of the combine harvester and the sieve, combined with the stalk and grass. Signal interference makes it extremely difficult to identify and extract grain signals. In addition, when the grain-grass mixture is discharged from the cleaning sieve, it continuously hits the sensitive element of the sensor installed at the back of the sieve. The traditional structure is to fix a single piezoelectric substrate on a flat plate. The grain obtained by this structure The information is incomplete and inaccurate, and it is also affected by its own performance and noise, and the collected data has great uncertainty. the

At present, when the cleaning loss automatic monitoring system based on single-chip microcomputer is actually used, the overall function, quantitative index and reliability of the whole machine are not high. The array piezoelectric crystal grain cleaning loss sensor is only a theoretical study without a specific implementation plan, and it cannot solve the problem of consistency of sensitivity of the array structure. the

Contents of the invention

The purpose of this utility model is to provide an intelligent on-line detection device for grain cleaning loss of a combine harvester with good real-time performance, high accuracy and strong reliability in view of the above-mentioned deficiencies in the prior art. the

The technical solution adopted by the utility model is: the output of the array piezoelectric crystal sensor is connected to the charge amplifier, and the output of the charge amplifier is sequentially connected in series with a gain-adjustable circuit, a high-pass filter circuit, a sensitivity adjustment circuit, a pulse shaping circuit, and a single-chip microprocessor and the communication interface circuit; the output of the sensitivity adjustment circuit is connected to the sensitivity voltage display digital tube, and the single-chip microprocessor is connected to the keyboard, the alarm circuit and the main display digital tube; the power supply circuit is respectively connected to the charge amplifier, the single-chip microprocessor, the keyboard, the main Display nixie tube, sensitivity voltage display nixie tube and each described circuit. the

The sensor plate-type sensitive element of the array piezoelectric crystal sensor is 40° to 60° from the horizontal position, and its two ends are adjustable and fixedly connected to the fixed bracket at the rear of the cleaning screen of the combine harvester. The piezoelectric detection array It is pasted on the back of the flat sensitive element of the sensor and sealed; a layer of elastic film is pasted on the front of the flat sensitive element of the sensor; one end of the shielded transmission wire is connected to the piezoelectric crystal detection array, and the other end is connected to the charge amplifier.

The beneficial effects of the utility model are: the detection loss of grain cleaning is detected by the method of multi-plate piezoelectric detection array full-width distribution, and the information is taken from multiple regions and angles, which not only enhances the impact signal of grains, improves the recognition accuracy of grain and grass, but also improves the Test reliability. The overall dynamic performance is good, the anti-interference ability is strong, the measurement accuracy is high, and it can realize the online measurement of cleaning loss in the field. the

Description of drawings

Fig. 1 is the structural connection diagram of the utility model. the

FIG. 2 is a structural diagram of the array piezoelectric crystal sensor 1 in FIG. 1 . the

In the figure, 1. Array piezoelectric crystal sensor; 2. Charge amplifier; 3. Gain adjustable circuit; 4. High-pass filter circuit; 5. Sensitivity adjustment circuit; 6. Pulse shaping circuit; 7. Single-chip microprocessor; 8. Keyboard; 9. Alarm circuit; 10. Main display digital tube; 11. Communication interface circuit; 12. Sensitivity voltage display digital tube; 13. Power supply circuit; 14. Piezoelectric crystal detection array; 15. Sensor flat sensitive element ; 16. Fixed bracket; 17. Shielded cable. the

Detailed ways

In the detection device shown in Figure 1, the output of the array piezoelectric crystal sensor 1 is connected to the charge amplifier 2, and the output of the charge amplifier 2 is sequentially connected in series with the gain adjustable circuit 3, the high-pass filter circuit 4, the sensitivity adjustment circuit 5, and the pulse shaping circuit 6. Single-chip microprocessor 7 and communication interface circuit 11. Wherein, the output of the sensitivity adjustment circuit 5 is bypassed to the sensitivity voltage display digital tube 12 , and the output of the single-chip microprocessor 7 is also connected to the alarm circuit 9 and the main display digital tube 10 . The output of the keyboard 8 is connected to the single-chip microprocessor 7 . Power supply circuit 13 connects above-mentioned each circuit respectively and provides power supply for each circuit, and power supply circuit 13 also connects charge amplifier 2, single-chip microprocessor 7, keyboard 8, main display nixie tube 10 and sensitivity voltage display nixie tube 12 respectively and provides It provides power. The power supply circuit 13 adopts DC12V outputted by the storage battery on the combine harvester as its voltage input, and adopts a voltage stabilizing circuit to obtain stable power supply voltage levels of DC±12V and DC5V. the

Referring to FIG. 2 , the structure of the arrayed piezoelectric crystal sensor 1 includes a piezoelectric crystal detection array 14 , a sensor plate-type sensitive element 15 , a fixing bracket 16 and a shielded cable 17 . The sensor plate-type sensitive element 15 is arranged to form an angle of 40°～60° with the horizontal position and is fixed on the fixed bracket 16 at the rear of the cleaning screen of the combine harvester, and is distributed in the width direction for detection. The piezoelectric detection array 14 is attached to the back of the sensor flat sensitive element 15 and sealed. A layer of elastic film is pasted on the front of the sensor flat sensitive element 15, and when the grain hits the surface of the sensor flat sensitive element 15, the elastic film can reduce the bending wave generated by the grain inside the sensor flat sensitive element 15. the

The piezoelectric crystal detection array 14 is composed of several disc-shaped piezoelectric ceramic crystals arranged at intervals. The flat panel sensitive elements 15 of the sensor are distributed together in the full width direction of the left, middle and right positions. The fixed bracket adopts four corners reinforcement mode to be fixed on the two ends of the sensor flat sensitive element 15, and the fixed bracket 16 is an adjustable structure up and down, front and rear positions of the sensor flat sensitive element 15. In order to make the piezoelectric ceramic crystal fully contact with the plane of the sensor flat sensitive element 15, the shielded transmission wire 17 is connected to the piezoelectric crystal detection array 14 in a single-sided lead mode, and one end of the shielded transmission wire 17 is connected to the piezoelectric crystal detection array 14, and the other end is connected to the piezoelectric crystal detection array 14. Connect charge amplifier 2. the

What single-chip microprocessor 7 selects is 80C52 single-chip microcomputer for use, collects three-way grain cleaning loss signal by data port. The keyboard 8 consists of three keys of "reset", "start" and "storage", wherein the "reset" key is used to initialize the program and perform system self-check; the "start" key is used to start the execution of the cleaning loss monitoring program, real-time Sampling and cleaning the lost grain signal, calculating the lost grain weight every 1 second, and refreshing the display; the "storage" key is used to query the total number of grain loss in the current working period. The communication interface circuit 11 adopts a MAX232 level conversion chip to form a serial RS232 communication mode. Grain cleaning loss monitoring system software is developed using C language. the

During the field harvesting process of the combine harvester, the array piezoelectric crystal sensor 1 is installed at the outlet of the cleaning sieve, distributed in the full width, and the impact signals of the throwing objects of the cleaning sieve are obtained from multiple areas and angles, and passed through the charge amplifier 2, gain The adjustable circuit 3, the high-pass filter circuit 4, the sensitivity adjustment circuit 5 and the pulse shaping circuit 6 are used for processing, and the signal of the grain lost during cleaning is extracted from the impact signals such as broken grass, straw, chaff and the interference of the strong vibration signal of the unit. For harvesting different crops, the reference voltage adjustment knob of the sensitivity adjustment circuit 5 can be changed to adjust the sensitivity voltages of the three channels and display them on the sensitivity voltage display digital tube 12 . The single-chip microprocessor 7 provides two working modes: "on-line monitoring" and "data query", which are selected and switched by the keyboard 8 . In the "online monitoring" mode, the single-chip microprocessor 7 collects grain cleaning loss signals through the data port, and the monitoring program counts and processes the collected grain signals, and displays the results on the main display digital tube 10 in real time. On-line monitoring of the cleaning loss is completed. If the grain loss exceeds the set limit value, the alarm circuit 9 sends an order to instruct the operator to take corresponding measures. As the intelligent terminal of the monitoring system, it accepts the remote management of the host computer through the real-time data transmission between the communication interface circuit 11 and the host computer. Under the "data query" mode, the single-chip microprocessor 7 calls out the total number of lost grains in the current working period, which is used to evaluate the quality status of the harvesting operation. the

Combine harvester grain cleaning loss detection method specifically includes the following steps:

1. Three sensor flat-type sensitive elements 15 are used to distribute at the grain outlet of the cleaning and screening according to the full width of the left, middle and right positions. The sensor plate-type sensitive element 15 has the structural parameter of optimally distinguishing the impact force of grain and grass, and can measure the highest frequency of grain impact. The multi-thin-plate structure can improve the resolution of the grain impact signal of the flat sensitive element 15 of the sensor; the full-width distribution form can maximize the acquisition of the cleaning loss grain signal. The flat sensitive element 15 of the sensor is installed at an angle of 40° to 60° with the horizontal plane to avoid secondary collisions caused by thrown objects hitting the surface of the flat sensitive element 15 of the sensor, and also to prevent chaff, short stems, etc. from hitting the flat sensor After the type sensitive element 15 is piled up on its surface, the sensitivity of the sensor flat type sensitive element 15 is reduced. the

When designing the sensor plate-type sensitive element 15, the dynamic model of the grain loss sensitive element is first established using the elastic thin plate theory, and then the dynamic model is used to calculate the sensor plate-type sensitive element that can measure the highest frequency of grain impact according to the law of grain falling. Parameters of the component 15, the obtained parameters are: length 300mm, width 200mm, thickness 1.5mm. the

2. The piezoelectric crystal detection array 14 is arranged on the back of the flat sensor 15 of the sensor. When the straw mixture randomly hits different positions on the surface of the flat sensor 15 of the sensor, the piezoelectric crystal detection array 14 captures information from multiple regions and multiple angles. Due to the particularity of the structure of the piezoelectric crystal detection array 14, it can not only enhance the impact signal of the grains, improve the recognition accuracy of the grain and grass, but also ensure that the flat sensor 15 of the sensor has similar sensitivity to the impact of the grain and grass mixture in the entire range. the

The concrete design method of piezoelectric crystal detection array 14 structure is as follows:

1) Using the grain signal sensing model and the electrical equation of the piezoelectric crystal to derive the grain loss signal measurement model

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 31</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}$

Among them: U _o is the open circuit voltage of the piezoelectric crystal, C is the feedback capacitance of the pre-charge amplifier, d ₃₁ is the piezoelectric constant, C ₁₁ is the elastic constant of the piezoelectric crystal, S ₁ is the deformation of the piezoelectric crystal, and S _p is The plate area of the piezoelectric crystal, a is the loss coefficient;

When cleaning and losing grains impact the flat sensor 15 of the sensor at a certain speed, the amplitude of the grain signal is proportional to the deformation of the piezoelectric crystal after being impacted, so the position where the deformation of the sensitive element is relatively large is selected for sensing. A relatively large amount of induced charge can be obtained to achieve the purpose of enhancing the signal of grains and improving the reliability of detection. the

2) Combining finite element method and test analysis method to analyze the dynamic model of the plate-type sensitive element 15 of the grain-grass impact sensor, and determine its low-order natural frequency and corresponding mode shape distribution. the

3) According to the vibration mode distribution in step 2), select the position where the dynamic deformation of the sensor plate-type sensitive element 15 is obvious to lay out the piezoelectric crystal, construct the prototype of the detection array structure, achieve the purpose of enhancing the grain signal and improving the resolution of grain grass. the

4) Utilize ANSYS software to establish a finite element simulation model of the flat sensitive element 15 of the grain impact sensor, and correct the prototype of the array structure in step 1) according to the deformation contour and the numerical solution of the deformation displacement of the flat sensitive element 15 of the sensor, optimize the array structure, and ensure On the premise of enhancing the impact signal of grains, the detection array makes the sensitivity distribution of the sensor plate-type sensitive element 15 tend to be even in the whole range. the

3. Send the signal output by the array piezoelectric crystal sensor 1 to the charge amplifier 2 and the gain adjustable circuit 3 for processing, and convert it into a voltage signal with a certain amplitude; Separation of unit vibration noise and grain signal characteristics in domain and time domain. The high-pass filter circuit 4 determines that the lowest order to meet the filtering performance is the eighth order according to the grain signal transition band width and stop band attenuation, and the transition band growth rate is faster, and the cleaning loss valley can be extracted from the strong noise background of the unit to a greater extent Granular signal, with voltage-controlled voltage source topology as the basic unit, adopts cascading method. the

4, separate the vibration noise and the grain signal of cleaning loss in the step 3 and make it be shaped into the standard pulse signal that the single-chip microprocessor 7 can carry out by the pulse shaping circuit 6. In order to keep grain signal characteristics, the selection of the pulse width of pulse shaping circuit 6 is very important, if it is selected too wide, the delay time will be long, which will cause the omission of grain signal; if it is selected too narrow, the delay time will be short, it will cause Causes double counting of the grain signal. Collect 80 groups of grain loss signals during the cleaning process, and use mathematical statistics to analyze the law of grain signal decay time, so as to determine the pulse width as 5ms~6ms. the

5. In the "online monitoring" mode, the single-chip microprocessor 7 collects grain cleaning loss signals at regular intervals, and the monitoring program counts and processes the collected grain signals, and displays the results on the main computer in real time. The display on the digital tube 10 is refreshed every 1 second to complete the online monitoring of the cleaning loss, and can transmit data with the host computer in real time to accept the remote management of the host computer. If the amount of grain loss exceeds the set limit value, an alarm command is sent through the alarm circuit 9 to instruct the operator to take corresponding measures. Under the "data query" mode, the single-chip microprocessor 7 calls out the total number of lost grains in the current working period, which is used to evaluate the quality status of the harvesting operation. the

Claims (4)

1. a combine grain cleaning loses the intelligent online checkout gear, it is characterized by: the output of array piezoeletric quartz sensor (1) connects charge amplifier (2), and the output of charge amplifier (2) is connected in series gain conditioned circuit (3), high-pass filtering circuit (4), sensitivity adjusting circuit (5), pulse shaper (6), onechipmicroprocessor (7) and communication interface circuit (11) successively; The other sensitivity voltage that connects of the output of sensitivity adjusting circuit (5) shows charactron (12), and onechipmicroprocessor (7) connects keyboard (8), warning circuit (9) and the main charactron (10) that shows; Power circuit (13) connects charge amplifier (2), onechipmicroprocessor (7), keyboard (8), main charactron (10), sensitivity voltage demonstration charactron (12) and each the described circuit of showing respectively.

2. combine grain cleaning loss intelligent online checkout gear as claimed in claim 1, it is characterized by: the sensor plate formula sensing element (15) of described array piezoeletric quartz sensor (1) becomes with horizontal level on the fixed support (16) at the adjustable sorting screen rear portion that is fixedly connected on combine in 40 °～60 ° and its two ends, and piezoelectric effect array (14) is applied to the back side of sensor plate formula sensing element (15) and sealed; Be pasted with one deck elastic film in sensor plate formula sensing element (15) front; Shielding transfer wire (17) one ends connect piezo-electric crystal detection array (14), and the other end connects described charge amplifier (2).

3. combine grain cleaning loss intelligent online checkout gear as claimed in claim 2, it is characterized by: piezo-electric crystal detection array (14) has a plurality of discoid piezoceramics crystals and is spaced; Having three sensor plate formula sensing elements (15) distributes by position, left, center, right same full width orientation.

4. combine grain cleaning loss intelligent online checkout gear as claimed in claim 3 is characterized by: the long 300mm of being of described sensor plate formula sensing element (15), and wide is 200mm, thickness is 1.5mm.

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