An adaptive control method applied to a combine harvester

Abstract

The application discloses a self-adaptive regulation method applied to a combine harvester, the combine harvester comprising a mobile chassis and a plucking and harvesting device, a material conveying channel, a threshing device and a cleaning device which are installed on the mobile chassis; the cleaning device comprises a vibrating screen and a vibrating screen driving mechanism; a plurality of vibrating screens are closely arranged; the vibrating screen driving mechanism comprises a central driving shaft and a plurality of eccentric shafts; the number of the eccentric shafts is equal to that of the vibrating screens, and the eccentric shafts and the vibrating screens are connected through connecting pieces one by one; the two ends of the eccentric shafts are connected with the central driving shaft through electric push rods; one end of the connecting piece is rotatably installed relative to the eccentric shaft, and the other end is fixed on the vibrating screen; all the electric push rods are connected with a controller; the method comprises the following steps: obtaining material distribution information falling on each vibrating screen to obtain left and right distribution conditions of the material; and based on the left and right distribution conditions, the rotation of each electric push rod is adjusted to adjust the amplitude of each vibrating screen.

Description

Technical Field

[0001] This invention relates to the field of harvester control technology, and in particular to an adaptive control method for combine harvesters. Background Technology

[0002] Combine harvesters are essential agricultural harvesting equipment, integrating harvesting, threshing, and cleaning operations, significantly improving efficiency in harvesting crops such as rapeseed, rice, and wheat. The cleaning effect of combine harvesters directly affects the final grain purity and harvest loss rate. Existing technologies generally employ an integrated vibrating screen structure, which, while achieving basic cleaning functions and, as shown in patents such as CN209736072U, can achieve intelligent cleaning functions by adjusting certain parameters, faces many limitations in actual operation: due to variations in crop variety, field conditions, and feed rate, the material often exhibits significant lateral unevenness on the screen surface. Especially during high-feed operations, the centrifugal force of the threshing drum causes material to accumulate on both sides of the screen surface, resulting in less material in the central area and severe accumulation on the sides. Traditional single-screen structures cannot respond differently to this, often leading to problems such as edge clogging and uneven screening between the left and right sides of the screen, resulting in insufficient grain cleaning or loss due to straw discharge. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the prior art, the present invention provides an adaptive control method for combine harvesters that can adaptively differentiate and control relevant components based on the distribution of materials to ensure that materials are fully cleaned.

[0004] Technical solution: To achieve the above objectives, the present invention provides an adaptive control method for a combine harvester, the combine harvester comprising a mobile chassis and a harvesting device, a material conveying channel, a threshing device, and a cleaning device mounted on the mobile chassis; the cleaning device comprises a vibrating screen and a vibrating screen drive mechanism;

[0005] Multiple vibrating screens are arranged closely together; the vibrating screen drive mechanism includes a central drive shaft and multiple eccentric shafts; the number of eccentric shafts and vibrating screens are equal, and each is connected to the other via a connector; both ends of the eccentric shafts are connected to the central drive shaft via electric push rods; one end of each connector is rotatably mounted relative to the eccentric shaft, and the other end is fixed to the vibrating screen; the central drive shaft is composed of multiple discontinuous shaft segments, and the electric push rods connect adjacent shaft segments to the ends of the eccentric shafts; since the electric push rods need to rotate continuously with the central drive shaft, electric slip rings can be configured to connect the electric push rods to transmit signals and power in order to supply power to the electric push rods; all the electric push rods are connected to a controller; the control method is connected by the controller.

[0006] The method includes:

[0007] Obtain the material distribution information falling on each of the vibrating screens to obtain the left-right distribution of the material;

[0008] Based on the aforementioned left-right distribution, the operation of each of the electric push rods is adjusted to regulate the amplitude of each of the vibrating screens. Adjusting the amplitude can change the vibration amplitude of the material; the larger the amplitude, the greater the distance the material is thrown, which is more conducive to the grain passing through the screen.

[0009] Furthermore, the length of the connector is automatically adjusted; the method also includes:

[0010] Based on the aforementioned left-right distribution, the overall length of the connecting member is adjusted. This allows for adjustment of the vibrating screen's direction angle, which in turn changes the material's forward speed, and consequently, the material's residence time on the screen surface.

[0011] Furthermore, the method also includes:

[0012] The target rotational speed of the threshing drum in the threshing device is determined based on the amount of material conveyed in the material conveying channel.

[0013] Based on the target rotation speed, the distribution of the falling material is predicted, and the operation of the electric push rod and the connecting part is controlled accordingly to perform pre-compensation on the vibration parameters of the vibrating screen.

[0014] The vibration parameters are further adjusted based on the actual obtained left-right distribution.

[0015] Furthermore, adjusting the operation of each of the electric push rods based on the left-right distribution to adjust the amplitude of each of the vibrating screens includes:

[0016] The unevenness of material distribution is calculated based on the left-right distribution pattern. The formula for calculating the unevenness of material distribution is as follows:

[0017]

[0018] in, These are the monitoring parameters corresponding to the i-th vibrating screen; These are the monitoring parameters corresponding to all the vibrating screens at the same time; The total number of vibrating screens; the monitoring parameter can be thickness data;

[0019] Determine the relationship between the imbalance and the preset threshold; if the imbalance is greater than the preset threshold, adjust the vibration parameters of each vibrating screen; if the imbalance is less than or equal to the preset threshold, make all the vibrating screens operate with the same vibration parameters. At this time, the amplitude and vibration direction angle of all the vibrating screens are consistent, so that all the vibrating screens are relatively assembled into a large screen body for cleaning operations.

[0020] Furthermore, the step of predicting the material distribution based on the target rotational speed and controlling the operation of the electric push rod and the connecting part to pre-compensate the vibration parameters of the vibrating screen includes:

[0021] The cleaning device is divided along the width direction into There are several material feeding zones, among which This represents the total number of vibrating screens. The number of zones corresponding to each vibrating screen;

[0022] Based on the target rotational speed Calculate the material cutting ratio for each zone. :

[0023]

[0024] in, The influence coefficient of rotational speed. It is a distribution pattern index. The reference speed; This is the partition number, with a value from 1 to... ; For the first Normalized position coordinates of each partition;

[0025] Calculate the total material discharge ratio corresponding to each of the vibrating screens. ;

[0026] The total material discharge ratio corresponding to all the vibrating screens is normalized to obtain the normalized total material discharge ratio. ;

[0027] Calculate the pre-adjustment amplitude corresponding to each of the vibrating screens. and front-mounted steering angle adjustment And accordingly control the operation of the electric push rod and the connecting piece; and The calculation is based on the following formula:

[0028]

[0029]

[0030] in, Basic amplitude; Amplitude minus load factor; This is the position compensation coefficient; Basic direction angle; The gain coefficient is adjusted by the direction angle. This is a non-linear factor.

[0031] Further, obtaining the material distribution information falling on each of the vibrating screens to obtain the left-right distribution of the material includes:

[0032] The radar positioned above the vibrating screen scans the screen surface to obtain material thickness data at various locations above the screen. This data is then processed to determine the left-right distribution of the material. The radar can be either a lidar or an ultrasonic radar. Because the vibrating screen moves dynamically and asynchronously, the material thickness on each screen can be scanned and identified separately. The controller synchronously acquires the position information of the vibrating screen and the radar scan data, combining the screen's position and the scanned data to calculate the material thickness. Since the vibrating screen's movement speed is much lower than the ultrasonic radar's scanning speed, the impact of the vibrating screen's movement during scanning can be ignored.

[0033] Beneficial effects: The adaptive control method of the present invention applied to combine harvesters has the following beneficial effects:

[0034] (1) In this invention, by replacing the traditional integral vibrating screen with multiple narrow vibrating screens that can vibrate individually and whose vibration parameters can be adjusted independently, the control system adjusts the vibration parameters of each vibrating screen in real time based on the left and right distribution of the material. This can achieve effective cleaning of the material when the material distribution on the screen surface is uneven, and prevent the problem of low screening rate and high loss rate caused by uneven local distribution of the material.

[0035] (2) The faster the rotation speed of the threshing drum, the more obvious the distribution phenomenon of more material on both sides and less material in the middle within the width range of the cleaning device becomes. Based on the predicted target rotation speed of the threshing drum, the parameters of the vibrating screen are pre-compensated. The vibration parameters can be adjusted before the material reaches the screen surface to improve the response speed. Furthermore, the cleaning effect can be improved based on the actual left and right distribution.

[0036] (3) By statistically quantifying the uneven distribution, the collaborative mode of the vibrating screen is adaptively switched. When the uneven distribution is high, the differentiated operation alleviates local blockage, and when the uneven distribution is low, the synchronous operation reduces energy consumption, thus balancing cleaning efficiency and system stability.

[0037] (4) In the pre-compensation scheme, a three-level optimization architecture is adopted to address the problem of uneven material distribution caused by the width of the screen surface: First, the width range of each vibrating screen is subdivided into m partitions, and the high-resolution material distribution is predicted based on the rotation speed of the threshing drum to quantify the physical law of material diffusion to both sides caused by the increase of rotation speed; Second, the total material discharge ratio of a single screen is generated by aggregating the partition data, and the control parameters are compressed while retaining the distribution characteristics; Finally, the vibration parameters of each vibrating screen are pre-compensated based on the respective characteristics. Attached Figure Description

[0038] Figure 1This is a general structural diagram for use in combine harvesters;

[0039] Figure 2 This is a structural diagram of the cleaning device;

[0040] Figure 3 for Figure 2 Enlarged structural diagram of section A;

[0041] Figure 4 This is a structural diagram of the vibrating screen drive mechanism in another embodiment;

[0042] Figure 5 This is a flowchart illustrating the adaptive control method applied to combine harvesters.

[0043] In the diagram: 1-Harvesting device; 2-Material conveying channel; 3-Threshing device; 31-Threshing drum; 4-Cleaning device; 41-Vibrating screen; 42-Vibrating screen drive mechanism; 421-Central drive shaft; 422-Eccentric shaft; 423-Connecting part; 424-Electric push rod; 5-Mobile chassis. Detailed Implementation

[0044] The invention will now be further described with reference to the accompanying drawings.

[0045] This invention provides an adaptive control method for combine harvesters, such as... Figure 1 As shown, the combine harvester includes a mobile chassis 5 and a harvesting device 1, a material conveying channel 2, a threshing device 3, and a cleaning device 4 installed on the mobile chassis.

[0046] like Figure 2As shown, the cleaning device 4 includes a frame, a vibrating screen 41, and a vibrating screen drive mechanism 42. Multiple vibrating screens 41 are arranged closely together. In the illustrated embodiment, there are three vibrating screens 41. In other embodiments, there may be five or seven vibrating screens 41. Each vibrating screen 41 is a narrow strip-shaped screen body, and the overall width of all vibrating screens 41 is consistent with the width of the cleaning screen of a traditional combine harvester. The vibrating screen drive mechanism 42 includes a central drive shaft 421 and multiple eccentric shafts 422. The number of eccentric shafts 422 and vibrating screens 41 is equal, and they are connected one by one via connectors 423. The connectors 423 connect to the rear end of the corresponding vibrating screen 41, and rollers are installed at the front end of the vibrating screen 41. An inclined guide rail is installed at the front end of the frame, and the rollers can move along the guide rail; both ends of the eccentric shaft 422 are connected to the central drive shaft 421 via electric push rods 424; one end of the connector 423 is rotatably mounted relative to the eccentric shaft 422, and the other end is fixed to the vibrating screen 41; the central drive shaft 421 is composed of multiple discontinuous shaft segments, and the electric push rods 424 connect adjacent shaft segments to the shaft ends of the eccentric shaft 422; since the electric push rods 424 need to rotate continuously with the central drive shaft 421, in order to power the electric push rods 424, an electric slip ring can be configured to connect the electric push rods 424 to transmit signals and power; all the electric push rods 424 are connected to a controller; the control method is implemented by the controller.

[0047] The method includes the following steps S101-S103:

[0048] Step S101: Obtain the material distribution information falling on each of the vibrating screens 41 to obtain the left and right distribution of the material;

[0049] In step S102, based on the left-right distribution, the operation of each of the electric push rods 424 is adjusted to regulate the amplitude of each of the vibrating screens 41. Adjusting the amplitude can change the vibration amplitude of the material; the larger the amplitude, the greater the amplitude of the material being thrown, which is more conducive to the grain passing through the screen.

[0050] Preferably, the length of the connector 423 can be manually adjusted (e.g., Figure 2 (as shown) or automatic adjustment (such as) Figure 3 As shown in the figure, in this embodiment, the connecting member 423 is a hydraulic cylinder or an electric push rod; based on this, the method further includes:

[0051] Step S103: Based on the left-right distribution, adjust the overall length of the connecting member 423. This allows adjustment of the direction angle of the vibrating screen 41, which changes the material's forward speed, and thus the residence time of the material on the screen surface.

[0052] In this invention, by replacing the traditional integral vibrating screen with multiple narrow vibrating screens 41 that can vibrate individually and whose vibration parameters can be adjusted independently, the control system adjusts the vibration parameters of each vibrating screen 41 in real time based on the left and right distribution of the material. This can achieve effective cleaning of materials when the material distribution on the screen surface is uneven, and prevent the problems of low screening rate and high loss rate caused by uneven local distribution of materials.

[0053] Preferably, the method further includes the following steps S201-S202:

[0054] Step S201: Determine the target rotation speed of the threshing drum 31 in the threshing device 3 based on the amount of material conveyed in the material conveying channel 2.

[0055] Step S202: Based on the target rotation speed, predict the distribution of the falling material, and control the operation of the electric push rod 424 and the connecting piece 423 to perform pre-compensation on the vibration parameters of the vibrating screen 41.

[0056] Step S203 involves further adjusting the vibration parameters based on the actual obtained left-right distribution. This step is essentially a further adjustment based on the aforementioned steps S101-S102.

[0057] The faster the threshing drum 31 rotates, the more pronounced the distribution of material on both sides and less in the middle becomes within the width of the cleaning device 4. By pre-compensating the parameters of the vibrating screen 41 based on the predicted target rotation speed of the threshing drum 31, the vibration parameters can be adjusted before the material reaches the screen surface, improving the response speed, and further enhancing the cleaning effect based on the actual left-right distribution.

[0058] Preferably, the step S102 above, which involves adjusting the operation of each of the electric push rods 424 based on the left-right distribution to adjust the amplitude of each of the vibrating screens 41, includes the following steps S301-S302:

[0059] Step S301: Calculate the material distribution imbalance based on the left-right distribution status. The formula for calculating the material distribution imbalance is:

[0060]

[0061] in, These are the monitoring parameters corresponding to the i-th vibrating screen 41; These are the monitoring parameters corresponding to all the vibrating screens 41 at the same time; The total number of the vibrating screens 41; the monitoring parameter can be thickness data;

[0062] Step S302: Determine the relationship between the imbalance and the preset threshold; when the imbalance is greater than the preset threshold, adjust the vibration parameters of each vibrating screen 41; when the imbalance is less than or equal to the preset threshold, make all the vibrating screens 41 operate with the same vibration parameters. At this time, the amplitude and vibration direction angle of all the vibrating screens 41 are consistent, so that all the vibrating screens 41 are relatively assembled into a large screen body for cleaning operations.

[0063] By statistically quantifying the uneven distribution, the collaborative mode of the vibrating screen is adaptively switched. When the uneven distribution is high, differentiated operation alleviates local blockage, while when the uneven distribution is low, synchronous operation reduces energy consumption, thus balancing cleaning efficiency and system stability.

[0064] Preferably, the step S202 above, which predicts the distribution of the falling material based on the target rotation speed and controls the operation of the electric push rod 424 and the connecting member 423 accordingly to pre-compensate the vibration parameters of the vibrating screen 41, includes the following steps S401-S405:

[0065] Step S401, the cleaning device 4 is divided along the width direction into... There are several material feeding zones, among which This refers to the total number of vibrating screens 41. The number of zones corresponding to each vibrating screen;

[0066] Step S402, based on the target rotational speed Calculate the material cutting ratio for each zone. :

[0067]

[0068] in, The influence coefficient of rotational speed. It is a distribution pattern index. The reference speed; This is the partition number, with a value from 1 to... ; For the first The normalized position coordinates of each partition; in this step, the material drop ratio calculation formula constructed based on the normalized position coordinates and distribution pattern index satisfies the characteristics of less material drop in the middle and more material drop on both sides, which can accurately describe the material drop distribution.

[0069] Step S403: Calculate the total material discharge ratio corresponding to each of the vibrating screens 41. Specifically, based on the formula Calculate the first The total material discharge ratio corresponding to each vibrating screen 41 That is, to summarize the material discharge ratio of each zone contained in each vibrating screen 41; since each vibrating screen 41 has a corresponding Each section has its own discharge ratio, which is calculated separately based on normalized position coordinates. Therefore, the accuracy of the total discharge ratio of each vibrating screen 41 is relatively high.

[0070] Step S404: Normalize the total material discharge ratio corresponding to all the vibrating screens 41 to obtain the normalized total material discharge ratio. Specifically, the normalization formula is as follows: ;

[0071] Step S405: Calculate the pre-adjustment amplitude corresponding to each of the vibrating screens 41. and front-mounted steering angle adjustment And accordingly control the operation of the electric push rod 424 and the connecting member 423; and The calculation is based on the following formula:

[0072]

[0073]

[0074] in, Basic amplitude; Amplitude minus load factor; This is the position compensation coefficient; Basic direction angle; The gain coefficient is adjusted by the direction angle. This is a non-linear factor. This is a normalized quantizer for the position of the screen body, used to map discrete screen body numbers to continuous standardized position coordinates, describing the relative position of the vibrating screen in the cleaning device. This quantizer can reflect that the compensation amount for the middle screen body is small, while the compensation amount for the two side screen bodies is large.

[0075] In the aforementioned pre-compensation scheme, a three-level optimization architecture is adopted to address the problem of uneven material distribution caused by the screen width: First, the width range of each vibrating screen 41 is subdivided into m zones, and the high-resolution material drop distribution is predicted based on the threshing drum speed, quantifying the physical law of material diffusion to both sides due to the increase in speed; second, the total material drop ratio of a single screen is generated by aggregating the zone data, compressing the control parameters while retaining the distribution characteristics; finally, the vibration parameters of each vibrating screen 41 are pre-compensated based on the individual characteristics.

[0076] Preferably, the step S101 above, which involves obtaining the material distribution information falling on each of the vibrating screens 41 to obtain the left-right distribution of the material, includes:

[0077] The radar positioned above the vibrating screen 41 scans the screen surface to obtain material thickness data at various locations above the vibrating screen 41. Based on this data processing, the left-right distribution of the material is determined. The radar can be a lidar or an ultrasonic radar. Since the vibrating screen 41 moves dynamically and asynchronously, the material thickness on each vibrating screen 41 can be scanned and identified separately. The controller synchronously acquires the position information of the vibrating screen 41 and the radar scan data, and calculates the material thickness by combining the position of the vibrating screen 41 and the scan data. Because the movement speed of the vibrating screen 41 is much lower than the scanning speed of the ultrasonic radar, the influence of the movement of the vibrating screen 41 during scanning can be ignored.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An adaptive control method for a combine harvester, the combine harvester comprising a mobile chassis and a harvesting device, a material conveying channel, a threshing device, and a cleaning device mounted on the mobile chassis; the cleaning device comprising a vibrating screen and a vibrating screen drive mechanism; characterized in that: Multiple vibrating screens are arranged closely together; the vibrating screen drive mechanism includes a central drive shaft and multiple eccentric shafts; the number of eccentric shafts and vibrating screens are equal, and each is connected to the other via a connector; the two ends of each eccentric shaft are connected to the central drive shaft via an electric push rod. One end of the connector is rotatably mounted relative to the eccentric shaft, and the other end is fixed to the vibrating screen; all the electric push rods are connected to the controller; The method includes: Obtain the material distribution information falling on each of the vibrating screens to obtain the left-right distribution of the material; Based on the left-right distribution, the operation of each of the electric push rods is adjusted to regulate the amplitude of each of the vibrating screens; The length of the connector is automatically adjusted; the method further includes: Based on the aforementioned left-right distribution, adjust the overall length of the connector; The method further includes: The target rotational speed of the threshing drum in the threshing device is determined based on the amount of material conveyed in the material conveying channel. Based on the target rotation speed, the distribution of the falling material is predicted, and the operation of the electric push rod and the connecting part is controlled accordingly to perform pre-compensation on the vibration parameters of the vibrating screen. The vibration parameters are further adjusted based on the actual obtained left-right distribution. The method of predicting the material distribution based on the target rotation speed, and controlling the operation of the electric push rod and the connecting parts accordingly to pre-compensate the vibration parameters of the vibrating screen, includes: The cleaning device is divided along the width direction into There are several material feeding zones, among which This represents the total number of vibrating screens. The number of zones corresponding to each vibrating screen; Based on the target rotational speed Calculate the material cutting ratio for each zone. : in, The influence coefficient of rotational speed. It is a distribution pattern index. The reference speed; This is the partition number, with a value from 1 to... ; For the first Normalized position coordinates of each partition; Calculate the total material discharge ratio corresponding to each of the vibrating screens. ; The total material discharge ratio corresponding to all the vibrating screens is normalized to obtain the normalized total material discharge ratio. ; Calculate the pre-adjustment amplitude corresponding to each of the vibrating screens. and front-mounted steering angle adjustment And accordingly control the operation of the electric push rod and the connecting piece; and The calculation is based on the following formula: in, Basic amplitude; Amplitude minus load factor; This is the position compensation coefficient; The basic direction angle; The gain coefficient is adjusted by the direction angle. is the nonlinear factor; i is the vibrating screen number.

2. The adaptive control method for a combine harvester according to claim 1, characterized in that, The adjustment of the operation of each electric push rod based on the left-right distribution to adjust the amplitude of each vibrating screen includes: The unevenness of material distribution is calculated based on the left-right distribution pattern. The formula for calculating the unevenness of material distribution is as follows: in, These are the monitoring parameters corresponding to the i-th vibrating screen; These are the monitoring parameters corresponding to all the vibrating screens at the same time; The total number of the vibrating screens; Determine the relationship between the imbalance and a preset threshold; if the imbalance is greater than the preset threshold, adjust the vibration parameters of each vibrating screen; if the imbalance is less than or equal to the preset threshold, make all the vibrating screens operate with the same vibration parameters.

3. The adaptive control method for a combine harvester according to claim 1, characterized in that, Obtain material distribution information falling on each of the vibrating screens to obtain the left-right distribution of the material, including: The radar placed above the vibrating screen scans the screen surface to obtain the material thickness data at various positions above the vibrating screen. Based on this data processing, the left-right distribution of the material is obtained.

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