A method and system for seed depth compensation based on terrain prediction

Abstract

The present application relates to the technical field of mechanical position servo control, and solves the problem of sowing depth fluctuation caused by position response lag and linear compensation failure of traditional profiling mechanism. The method comprises the following steps: obtaining the curvature characteristics of the front terrain through a terrain detection sensor, combining the structure parameters of the actuator with the predicted vertical displacement offset of the touchdown point, generating a drive actuator feedforward position instruction based on the offset and a preset depth target value, collecting the blade load disturbance value in real time, and classifying and correcting the output thrust according to the discrete disturbance gradient (nonlinear increase in thrust in hard soil area / stepwise decrease in thrust in soft soil area), and combining the furrow depth feedback to dynamically adjust the position of the actuator. Through the double closed-loop control of terrain-position feedforward and resistance-position feedback, the present application realizes independent prediction and accurate position tracking of the mobile platform on the micro terrain of the ground, so that the position output is consistent with the position target value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical position servo control, and in particular to a seeding depth compensation method and system based on terrain prediction. BACKGROUND

[0002] Traditional seeding machines use mechanical profiling mechanisms (such as counterweight connecting rods or whole profiling wheels) to maintain the furrow depth, and the essence is to realize position following through the gravity or spring force of the mechanism. Such passive control has fundamental defects: first, the mechanism only responds passively after the actuator contacts the terrain mutation, and cannot predict the curvature change in front (such as steep slope turning into pothole), resulting in instantaneous deviation of the furrow depth from the set position; second, the soil resistance is distributed discretely (the resistance increases sharply in hard ground area / the resistance decreases sharply in soft ground area), but the passive mechanism only provides constant or linearly changing down pressure, resulting in depth loss of control in the resistance extreme area: the actuator is lifted (undercompensation) due to insufficient thrust in hard soil area, and sinks (overcompensation) due to excessive thrust in soft soil area.

[0003] Although the existing electro-hydraulic position control system attempts to introduce depth sensor feedback, it still has two limitations: it only relies on the current actuator position feedback and does not fuse the front terrain geometric feature (curvature, slope) to predict the displacement offset; it uses fixed gain PID to adjust the hydraulic thrust, which cannot adapt to the non-continuous gradient change of soil resistance, and still produces depth oscillation in the resistance mutation area. SUMMARY

[0004] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present application provide a seeding depth compensation method based on terrain prediction to solve the problems raised in the background art.

[0005] To achieve the above-mentioned purpose, the present application provides a seeding depth compensation method based on terrain prediction, comprising:

[0006] obtaining terrain elevation data of a front working area through a controlled object installed on a mobile platform;

[0007] extracting the curvature change feature of the terrain elevation data, and converting the curvature change feature into a vertical displacement offset of the touch point of the actuator according to the structural parameters and the travel speed of the actuator;

[0008] generating a displacement compensation instruction for driving the actuator in real time according to the vertical displacement offset and a preset position target value;

[0009] in response to the displacement compensation instruction, driving the driving actuator to output an initial thrust, and collecting a load disturbance value of the actuator blade in real time;

[0010] When the load disturbance value exceeds a preset disturbance threshold range, the output thrust of the driving actuator is adjusted in a disturbance gradient classification manner;

[0011] The relative position between the actuator and the mobile platform is dynamically adjusted based on the output thrust, so that the position output is consistent with the position target value.

[0012] To solve the above problems, the application also provides a sowing depth compensation system based on terrain prediction, which comprises:

[0013] A terrain elevation data acquisition module is configured to acquire terrain elevation data of a front work area through a controlled object installed on a mobile platform;

[0014] A displacement offset generation module is configured to extract a curvature variation feature of the terrain elevation data, and convert the curvature variation feature into a vertical displacement offset of a contact point of an actuator according to structural parameters and a travel speed of the actuator;

[0015] A compensation instruction generation module is configured to generate a displacement compensation instruction of a driving actuator in real time according to the vertical displacement offset and a preset position target value;

[0016] A load disturbance value generation module is configured to drive the driving actuator to output an initial thrust in response to the displacement compensation instruction, and acquire a load disturbance value of a blade edge of the actuator in real time;

[0017] A thrust classification adjustment module is configured to adjust the output thrust of the driving actuator in a disturbance gradient classification manner when the load disturbance value exceeds a preset disturbance threshold range;

[0018] A position output consistent adjustment module is configured to dynamically adjust the relative position between the actuator and the mobile platform based on the output thrust, so that the position output is consistent with the position target value.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] 1. The application acquires terrain elevation data in front in real time through a laser range finder, extracts a curvature variation feature, combines an inclination angle of an action surface of an actuator, mass inertia parameters and a travel speed, establishes a position offset prediction model, compensates a phase of the curvature feature based on a travel speed to calculate a system response lag time, eliminates mechanical delay, maps the compensated curvature value to a vertical displacement offset of a contact point of the actuator, and generates a feedforward compensation instruction of a driving actuator, which quantifies terrain geometric features in real time to position control quantities, breaks through a bottleneck of open-loop response, adjusts a position before the actuator contacts terrain mutation, and eliminates a source error of depth fluctuation.

[0021] 2.The application constructs a thrust grading correction mechanism based on discrete resistance gradient on the basis of position feedforward control: real-time monitoring of the disturbance value of the blade load of the actuator, and dividing the disturbance threshold interval of hard / soft soil; when the resistance value enters the hard interval, the hydraulic output thrust is increased according to a nonlinear increasing function to ensure the position maintenance capability; when the resistance value enters the soft interval, the thrust is reduced according to a stepwise decreasing function to avoid position overshoot; in combination with the real-time feedback of the displacement sensor, the ditching depth deviation is triggered to trigger the thrust re-adjustment mechanism, the double closed-loop control breaks through the linear force control limitation, the position tracking accuracy is maintained when the soil resistance is discrete, and finally the seeding depth consistency is realized. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A flowchart of a seeding depth compensation method based on terrain prediction provided by an embodiment of the application is shown in the figure.

[0023] Figure 2 A functional module diagram of a seeding depth compensation system based on terrain prediction provided by an embodiment of the application is shown in the figure.

[0024] The implementation of the object of the application, the functional features and the advantages will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0025] It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.

[0026] Embodiments of the application provide a seeding depth compensation method based on terrain prediction. The execution subject of the seeding depth compensation method based on terrain prediction includes but is not limited to at least one of electronic devices such as a server, a terminal, etc. that can be configured to execute the method provided by the embodiments of the application. In other words, the seeding depth compensation method based on terrain prediction can be executed by software or hardware installed in a terminal device or a server device. The server includes but is not limited to a single server, a server cluster, a cloud server, or a cloud server cluster, etc. The server can be a stand-alone server, or a cloud server that provides cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content distribution networks, and big data and artificial intelligence platforms, etc. basic cloud computing services.

[0027] Referring to Figure 1 The figure shows a flowchart of a seeding depth compensation method based on terrain prediction provided by an embodiment of the application. In this embodiment, the seeding depth compensation method based on terrain prediction includes:

[0028] S1, obtaining terrain elevation data of a front work area through a controlled object installed on a mobile platform.

[0029] In the embodiments of the present application, the mobile platform is a single functional unit on the seeding machine capable of independently completing the ditching and seeding operations, can be independently adjusted in response to changes in the terrain, and can be a seeding unit; the controlled object is a device for collecting ground height information, which functions to obtain terrain data of the operation area before the seeding operation, and can be a terrain detection sensor; the operation area refers to the land area where the mobile platform is about to perform the seeding operation; and the terrain elevation data is a set of height values of each point on the ground surface in the operation area relative to a set reference surface.

[0030] In some embodiments, the terrain elevation data of the front operation area is obtained by the controlled object mounted on the mobile platform, including:

[0031] The laser range finder scans the operation area in front of the mobile platform, and converts the scanned point cloud data into terrain elevation data.

[0032] In the embodiments of the present application, the laser range finder is a device that measures distance by emitting laser and receiving reflected signals, and can be used to scan the ground to obtain three-dimensional coordinate information; the point cloud data is a data set composed of three-dimensional coordinates (including X, Y, and Z axis coordinates) of a large number of ground points scanned by the laser range finder, wherein the Z axis coordinate reflects the height information of the point.

[0033] First, the laser range finder is installed in front of the forward direction of the mobile platform, and the horizontal distance between the installation position and the actuator is set to 50 cm. This distance ensures that the terrain can be detected in advance, and avoids too large terrain prediction error caused by too far distance. The scanning parameters of the laser range finder are set as follows: scanning frequency 40 Hz, scanning width 1.0 m, i.e. 40 scans per second can be completed for a 1.0 m wide area in front, and 150 three-dimensional coordinate data of points can be generated each time. During the seeding operation, the laser range finder continuously emits laser beams to the operation area, the laser beams are reflected after encountering the ground surface, and the laser range finder receives the reflected signals and calculates the three-dimensional coordinates of each scanning point (with the forward direction of the mobile platform as the X axis, the direction perpendicular to the forward direction as the Y axis, and the direction perpendicular to the ground upward as the Z axis) to form point cloud data.

[0034] Subsequently, the obtained point cloud data is processed by coordinate conversion, and the Z axis coordinate value of each point is extracted. These Z axis coordinate values represent the height of the corresponding ground point relative to the reference surface, and thus the terrain elevation data of the operation area is obtained. For example, the three-dimensional coordinates of a point in the point cloud data obtained by a certain scan are (0.2 m, 0.3 m, 0.04 m), and the Z axis coordinate 0.04 m is taken as the terrain elevation data of the point. The coordinates of another point are (0.3 m, 0.4 m, 0.06 m), and the terrain elevation data thereof is 0.06 m.

[0035] In the embodiment of the present application, the step of obtaining the terrain elevation data in front of the working area in advance by the laser range finder breaks the limitation that the traditional passive profiling mechanism needs to be in contact with the ground surface to respond to the terrain changes, provides basic data for subsequent prediction and compensation of terrain changes, and helps to solve the problem of fluctuation of seeding depth caused by uneven ground surface (such as small amplitude protrusions or depressions).

[0036] S2, extracting a curvature change feature of the terrain elevation data, and converting the curvature change feature into a vertical displacement offset of a touch point of the actuator according to a structural parameter and a traveling speed of the actuator.

[0037] In the embodiment of the present application, the curvature change feature is an index reflecting the sudden change of the bending degree of the terrain, which is embodied by the abnormal change point of the terrain curvature radius; the actuator is a component on the mobile platform for cutting soil to form a seed trench, which can be a furrow opener; and the vertical displacement offset is a vertical deviation value of the touch point of the actuator relative to the reference position caused by the change of the terrain.

[0038] In some embodiments, the structural parameter includes an action surface inclination angle and a mass inertia parameter, wherein the action surface inclination angle is measured in real time by an angle sensor, and the mass inertia parameter is set in advance by a calibration test.

[0039] In the embodiment of the present application, the structural parameter is a parameter representing the mechanical property of the actuator; the action surface inclination angle is the included angle between the blade of the actuator and the horizontal plane, which can be the blade angle inclination angle of the furrow opener; the mass inertia parameter is an additional mass configured to adjust the soil penetration pressure of the actuator, which can be the configuration mass of the furrow opener; and the traveling speed is the forward speed of the mobile platform in the working process.

[0040] In some embodiments, the extracting the curvature change feature of the terrain elevation data comprises:

[0041] calculating a slope change rate between adjacent terrain elevation data points;

[0042] generating a terrain curvature radius sequence according to the slope change rate;

[0043] extracting a sudden change point in the curvature radius sequence as the curvature change feature.

[0044] In the embodiment of the present application, the slope change rate is the ratio of the slope difference between two adjacent terrain elevation data points to the horizontal distance, which is used to reflect the degree of change of the terrain slope; the curvature radius sequence is an ordered set composed of the curvature radii of a plurality of continuous terrain points, the curvature radius is a parameter representing the bending degree of the curve, and the smaller the value is, the more severe the bending is; and the sudden change point is a point in the curvature radius sequence where the value suddenly changes significantly.

[0045] In the embodiments of the present application, the process of extracting the curvature change feature is as follows: based on the terrain elevation data (for example, the elevation values of continuous points in a certain area are 0.03 m, 0.06 m, 0.04 m and 0.10 m) obtained in S1, the slope of adjacent points is first calculated. Taking two adjacent points A (elevation 0.03 m, X coordinate 0.1 m) and B (elevation 0.06 m, X coordinate 0.2 m), the slope is (0.06 m-0.03 m) / (0.2 m-0.1 m)=0.3; then taking point B and point C (elevation 0.04 m, X coordinate 0.3 m), the slope is (0.04 m-0.06 m) / (0.3 m-0.2 m)=-0.2. Then the slope change rate, that is, the ratio of the difference between the slopes of two points to the horizontal distance, is calculated. The slope change rate of point B relative to point A is (-0.2-0.3) / (0.3 m-0.1 m)=-2.5. The curvature radius is calculated according to the slope change rate, that is, the ratio of 1 to the absolute value of the slope change rate, that is, 1 / |-2.5|=0.4 m, thereby generating a curvature radius sequence (such as 0.5 m, 0.4 m and 0.2 m). Then the mutation point is extracted. When the curvature radius of a point in the sequence suddenly decreases from 0.4 m to 0.2 m (the change amplitude exceeds 50%), the point is the mutation point of the curvature change feature.

[0046] In some embodiments, the conversion of the curvature change feature into the vertical displacement offset of the touch point of the actuator according to the structural parameters of the actuator and the travel speed comprises:

[0047] calculating the response lag time of the actuator based on the travel speed of the actuator;

[0048] performing soil cutting resistance phase compensation on the curvature change feature according to the response lag time and the inclination angle of the acting surface, to generate a compensated curvature feature value;

[0049] multiplying the compensated curvature feature value by the mass inertia parameter to generate the vertical displacement offset of the touch point of the actuator.

[0050] In the embodiments of the present application, the response lag time is the time required from the detection of the terrain change by the terrain detection sensor to the actual contact of the actuator with the terrain; the soil cutting resistance phase compensation is a correction for eliminating the asynchronization between the soil cutting resistance and the terrain change caused by the response lag of the actuator; and the compensated curvature feature value is a value that can accurately reflect the curvature of the terrain when the actuator actually contacts the terrain after phase compensation.

[0051] In the embodiment of the present application, the process of converting the curvature change feature into the vertical displacement offset is as follows: first, the response lag time is calculated, the horizontal distance between the terrain detection sensor and the actuator is 0.6 m, the travel speed is 1.2 m / s, and the response lag time is the ratio of the horizontal distance to the travel speed, that is, 0.6 m / 1.2 m / s=0.5 s. Secondly, the cutting resistance phase compensation is carried out, the real-time angle sensor measures the angle of the working surface to be 25°, and the compensation amount is the product of the response lag time, the travel speed and the sine value of the angle of the working surface, that is, The compensation amount is superimposed on the position parameter of the curvature mutation point to obtain the compensated curvature feature value (for example, the curvature corresponding to the original curvature radius of 0.2 m is , and the compensated curvature feature value is . Finally, the compensated curvature feature value is multiplied by the mass inertia parameter (20 kg) set in advance through the calibration test to generate the vertical displacement offset, that is, (the calibration coefficient is determined by the field soil characteristic test)≈1.21 m, which is the vertical deviation of the touch point of the actuator that needs to be adjusted due to the change of the terrain.

[0052] In the embodiment of the present application, this step realizes the advance prediction of the micro-terrain change of the ground surface by converting the geometric feature of the terrain into the physical displacement parameter of the actuator, provides a quantitative basis for the subsequent depth compensation, and solves the depth adjustment lag problem of the traditional passive profiling mechanism caused by the inability to predict the terrain.

[0053] In the embodiment of the present application, this step breaks through the limitation of the traditional profiling mechanism that can only passively respond to the terrain, establishes a quantitative mapping relationship from the terrain feature to the physical displacement by combining the terrain curvature change with the structural parameters and motion parameters of the actuator, realizes the basis of active prediction type depth adjustment, and provides an innovative solution for the accurate control of the seeding depth.

[0054] S3, generating a displacement compensation instruction for driving the actuator in real time according to the vertical displacement offset and a preset position target value.

[0055] In the embodiment of the present application, the preset position target value is an ideal opening depth reference value set according to the growth requirement of crops, which can be a seeding depth target value; the driving actuator is a hydraulic driving device that receives control instructions and drives the actuator to adjust the vertical displacement, which can be a hydraulic actuator; and the displacement compensation instruction is a signal for controlling the action of the driving actuator, which contains the displacement information that the actuator needs to adjust.

[0056] In some embodiments, the displacement compensation instruction for driving the actuator in real time according to the vertical displacement offset and the preset position target value comprises:

[0057] Superimpose the vertical displacement offset to the reference stroke value corresponding to the position target value to generate a compensation stroke value for driving the actuator;

[0058] Generate a PWM control signal for driving the hydraulic proportional valve according to the compensation stroke value as a displacement compensation instruction for driving the actuator.

[0059] In the embodiments of the present application, the reference stroke value is the initial telescopic length required for driving the actuator to achieve the preset position target value; the compensation stroke value is the telescopic length actually required for driving the actuator after superimposing the vertical displacement offset on the reference stroke value; the hydraulic proportional valve is a control valve capable of proportionally adjusting the hydraulic flow and pressure according to the input electrical signal, used for controlling the action of the driving actuator; and the PWM control signal is a pulse signal capable of adjusting the output by changing the pulse width, which can be used to control the opening degree of the hydraulic proportional valve.

[0060] In some embodiments, the preset position target value is determined by selecting a reference depth interval according to the work object type, the work object type including a crop type, adjusting the reference depth interval based on a field calibration test, and generating a position target value.

[0061] In the embodiments of the present application, the specific process of determining the preset position target value is as follows: taking corn seeding as an example, according to the characteristics of corn crops, the reference depth interval is selected as 5-8 cm; then a field calibration test is carried out, and corn is seeded at depths of 5 cm, 6 cm, 7 cm and 8 cm in different areas of the test field respectively, the emergence rate and seedling growth of each depth are counted, and it is found that the emergence rate is the highest and the seedlings grow healthily at a depth of 6 cm, so the preset position target value is determined as 6 cm. The reference stroke value corresponding to the target value is calibrated by test, that is, when the driving actuator is telescoped by 4 cm, the execution mechanism can reach a furrowing depth of 6 cm, so the reference stroke value is set to 4 cm.

[0062] In the embodiments of the present application, the compensation stroke value for driving the actuator is generated by superimposing the vertical displacement offset of 1.21 cm obtained in S2 on the reference stroke value, i.e. compensation stroke value = 4 cm + 1.21 cm = 5.21 cm.

[0063] In the embodiments of the present application, the PWM control signal is generated by: the PWM control signal duty cycle of the hydraulic proportional valve has a linear correspondence with the compensation stroke value, and the correspondence is determined by pre-calibration, that is, when the compensation stroke value is 0 cm, the duty cycle is 0%; and when the compensation stroke value is 10 cm, the duty cycle is 100%. Therefore, the duty cycle corresponding to 5.21 cm is (5.21 cm / 10 cm) x 100% = 52.1%, and the PWM control signal with a duty cycle of 52.1% is generated, which is the displacement compensation instruction for driving the actuator.

[0064] In the embodiment of the present application, this step converts the displacement demand obtained by terrain prediction into specific action instructions for driving the actuator, enabling the actuator to adjust its position in advance to adapt to terrain changes, solving the depth adjustment lag problem caused by passive response of traditional profiling mechanisms, and helping to maintain the stability of the seeding depth.

[0065] In the embodiment of the present application, this step generates compensation instructions by combining the vertical displacement offset with the preset target value, breaking through the limitation of traditional passive profiling mechanisms that can only adjust according to real-time contact terrain, and providing a key instruction generation mechanism for accurate control of the seeding depth. This control method directly associates the terrain prediction result with the crop growth demand, enabling the mobile platform to more intelligently adapt to changes in the surface microtopography.

[0066] S4, in response to the displacement compensation instruction, driving the driving actuator to output an initial thrust, and collecting a load disturbance value of the actuator blade in real time.

[0067] In the embodiment of the present application, the initial thrust is the driving force that the driving actuator first outputs according to the displacement compensation instruction, used to push the actuator into the soil; the actuator blade is the sharp edge of the actuator that directly contacts the soil, used to cut the soil; and the load disturbance value, specifically the soil resistance value, is the soil reaction force that the actuator blade receives when it cuts into the soil.

[0068] In the embodiment of the present application, the specific process implemented by this step is as follows: first, the driving actuator receives the displacement compensation instruction generated in S3 (such as a PWM control signal with a duty cycle of 52.1%), which is converted into corresponding hydraulic flow and pressure through a hydraulic proportional valve. The hydraulic cylinder inside the driving actuator extends and retracts under the action of hydraulic pressure, outputting an initial thrust. The size of the initial thrust is related to the compensation stroke value, and their corresponding relationship is determined through pre-calibration, for example, a compensation stroke value of 5.21 cm corresponds to an initial thrust of 7.815 kN (calculation basis: thrust = hydraulic pressure × piston area, where the hydraulic pressure is controlled by the duty cycle of the PWM signal, and the piston area is a preset fixed value).

[0069] Secondly, a strain force sensor is installed at the actuator blade, which is rigidly connected to the blade and can sense the force of the soil on the blade in real time. The measurement range of the sensor covers the possible load disturbance value (such as 5-20 kN) in the working area, and the sampling frequency is set to 100 Hz to ensure that the instantaneous changes in resistance can be captured. The sensor converts the mechanical signal into an electrical signal, which is transmitted to the control system after amplification and filtering, forming real-time load disturbance value data. For example, when the actuator passes through a soil area containing small stones, the resistance value collected by the sensor may suddenly rise from 6.5 kN to 9.2 kN.

[0070] In the embodiment of the present application, this step ensures that the actuator cuts into the soil at the preset depth by outputting the initial thrust, while collecting the load disturbance value in real time, thereby providing a basis for adjusting the thrust according to the soil conditions in the subsequent step, and solving the problem that the traditional profiling mechanism cannot adapt to the difference in soil compactness due to the fixed thrust.

[0071] In the embodiment of the present application, this step combines the action of the actuator with real-time resistance detection, breaking through the limitation of the traditional profiling mechanism that only passively adapts to the mechanical structure.

[0072] S5, when the load disturbance value exceeds the preset disturbance threshold range, the output thrust of the driving actuator is adjusted according to the disturbance gradient.

[0073] In the embodiment of the present application, the disturbance gradient classification is a way of dividing the load disturbance value into different levels according to the size difference, and matching a specific thrust adjustment strategy for each level.

[0074] In some embodiments, when the load disturbance value exceeds the preset disturbance threshold range, the output thrust of the driving actuator is adjusted according to the disturbance gradient, including:

[0075] The load disturbance extreme value of the hard hard trash area and the soft pit area is divided into a disturbance threshold interval according to the load disturbance extreme value distribution;

[0076] When the load disturbance value enters the hard soil area, the output thrust is increased according to a linear increasing function;

[0077] When the load disturbance value enters the soft soil area, the output thrust is decreased according to a stepwise decreasing function.

[0078] In the embodiment of the present application, the hard hard trash area is an area in the soil containing hard soil blocks or compacted layers, which has a larger resistance to the actuator; the soft pit area is an area with loose soil structure or concave structure, which has a smaller resistance to the actuator; the load disturbance extreme value is the maximum resistance value measured in the hard hard trash area and the minimum resistance value measured in the soft pit area; the disturbance threshold interval is a continuous numerical range for judging whether the soil resistance is normal, which is divided based on the load disturbance extreme value.

[0079] In the embodiment of the present application, the linear increasing function refers to a mathematical relationship in which the output thrust increases linearly with time or resistance value. The stepwise decreasing function refers to a mathematical relationship in which the output thrust decreases in stages with a fixed amplitude.

[0080] First, the load disturbance extreme value of hard clod area and soft pit area is measured, including: in the land to be seeded, typical hard clod area and soft pit area are selected, and multi-point measurement is performed by using a strain force sensor installed at the cutting edge of the actuator. For example, the maximum resistance value measured in the hard clod area is 18 kN, and the minimum resistance value measured in the soft pit area is 5 kN. According to the two extreme values, the disturbance threshold interval is divided: the normal soil area is 8-15 kN (the appropriate resistance range determined by field test), the hard soil area is 15-18 kN, and the soft soil area is 5-8 kN.

[0081] When the load disturbance value collected in S4 enters the hard soil area (such as 16 kN), the output thrust is adjusted according to a linear increasing function. The linear increasing function is set as F=F0+k×t, where F0 is the current thrust (such as 7.815 kN output in S4), k is the increasing coefficient (0.4 kN / s, determined by soil hardness test), and t is the duration of the resistance value in the area. If the duration is 3 s, the adjusted thrust is 7.815+0.4×3=9.015 kN, and the thrust is gradually increased to ensure that the actuator can cut into the hard soil, avoiding the shallow depth of the trench caused by excessive resistance.

[0082] When the load disturbance value enters the soft soil area (such as 6 kN), the output thrust is adjusted according to a step decreasing function. The step decreasing function is set to decrease by 1.2 kN per step, and the initial thrust is 7.815 kN. The first step after adjustment is 6.615 kN, and if the resistance is still in the area, the second step after adjustment is 5.415 kN. The thrust is gradually reduced to prevent the actuator from being excessively inserted into the soil due to insufficient resistance, and to avoid excessive depth of the trench.

[0083] In the embodiment of the application, the output thrust of the driving actuator is matched with the soil resistance through the targeted thrust adjustment strategy, solving the problem that the traditional profiling mechanism cannot adapt to the difference in soil firmness due to fixed thrust, and reducing the fluctuation of seeding depth caused by abnormal resistance.

[0084] In the embodiment of the application, this step breaks through the limitation of single thrust control of the traditional profiling mechanism, divides the interval according to the measured extreme value, and adjusts the thrust by using a differentiated function, realizing dynamic adaptation of the thrust to the soil resistance. This step-by-step adjustment strategy avoids the shallow trench caused by insufficient thrust in the hard area, and prevents the excessive depth of the trench caused by excessive thrust in the soft area, providing a precise power control scheme for the mobile platform to cope with complex soil conditions, and is a key link to realize independent, real-time and precise closed-loop control.

[0085] S6, dynamically adjusting the relative position of the actuator and the mobile platform based on the output thrust, so that the position output is consistent with the position target value.

[0086] In the embodiments of the present application, the relative position refers to the position relationship of the actuator in the vertical direction relative to the moving platform frame; and the trenching depth refers to the vertical distance from the blade to the ground after the actuator cuts into the soil.

[0087] In some embodiments, the dynamic adjustment of the relative position of the actuator and the moving platform based on the output thrust makes the position output consistent with the position target value, comprising:

[0088] The displacement sensor is used to detect the depth of the actuator in real time.

[0089] When the deviation of the depth of the actuator from the position target value exceeds the tolerance threshold, the output thrust is re-adjusted.

[0090] In the embodiments of the present application, the displacement sensor is a device capable of measuring the position change of an object in real time, which is used to monitor the vertical movement distance of the actuator; the depth of the actuator refers to the actual depth of the actuator cutting into the soil under the action of the thrust; the tolerance threshold refers to the maximum deviation range allowed between the depth of the actuator and the preset position target value; and the re-adjustment refers to the re-adjustment of the output thrust of the driving actuator according to the depth deviation.

[0091] First, the displacement sensor is installed at the connection part of the actuator and the moving platform, the measurement range of the sensor covers the possible movement interval of the actuator (such as 0-20 cm), and the sampling frequency is set to 100 Hz to ensure real-time performance. During the sowing operation, the displacement sensor continuously detects the depth of the actuator and transmits the detection data to the control system. For example, the preset position target value is 6 cm, and the tolerance threshold is set to ±0.5 cm (determined by field test to ensure that the emergence rate is not significantly affected).

[0092] When the displacement sensor detects that the depth of the actuator is 6.7 cm, the deviation from the target value is 0.7 cm, which exceeds the tolerance threshold (0.5 cm). The control system feeds back this deviation signal to the thrust adjustment link to trigger the re-adjustment of the output thrust. If the deviation is positive (the depth is too deep), the output thrust of the driving actuator is reduced in proportion to the deviation, for example, from the current 9.015 kN to 8.215 kN, to reduce the soil penetration pressure of the actuator; if the detected depth of the actuator is 5.3 cm, the deviation is -0.7 cm (the depth is too shallow), and the output thrust is increased in proportion to the deviation, for example, from 7.815 kN to 8.615 kN, to increase the soil penetration pressure, until the depth of the actuator returns to the range of 6 cm±0.5 cm.

[0093] In the embodiment of the present application, this step forms a complete closed-loop control by detecting the depth deviation in real time and feeding back the adjustment of the pushing force, ensures that the ditching depth is not affected by the terrain undulations and the changes in soil resistance, and solves the depth fluctuation problem caused by the lack of accurate feedback of the traditional profiling mechanism.

[0094] In the embodiment of the present application, this step realizes dynamic correction of the seeding depth through the closed-loop design of depth detection and pushing force re-adjustment. This real-time feedback mechanism can quickly respond to subtle changes in terrain and soil conditions, enabling the mobile platform to independently adapt to micro-terrain, and is the ultimate guarantee for realizing accurate closed-loop control. By directly associating the depth deviation with the pushing force adjustment, the timeliness and accuracy of the control process are ensured, further improving the stability of the seeding depth.

[0095] As shown in Figure 2 FIG. 1 is a functional module diagram of a terrain-predicted seeding depth compensation system according to an embodiment of the present application.

[0096] The terrain-predicted seeding depth compensation system 100 according to the present application can be installed in an electronic device. According to the functions to be implemented, the terrain-predicted seeding depth compensation system 100 can include a terrain elevation data acquisition module 101, a displacement offset generation module 102, a compensation instruction generation module 103, a load disturbance value generation module 104, a pushing force hierarchical adjustment module 105, and a position output consistent with the position target value adjustment module 106. The modules according to the present application can also be referred to as units, which refer to a series of computer program segments that can be executed by an electronic device processor and can complete fixed functions, and are stored in the memory of the electronic device.

[0097] In the embodiment, the functions of each module / unit are as follows:

[0098] The terrain elevation data acquisition module 101 is configured to acquire terrain elevation data of a front work area through a controlled object installed on a mobile platform.

[0099] The displacement offset generation module 102 is configured to extract a curvature variation feature of the terrain elevation data, and convert the curvature variation feature into a vertical displacement offset of a touch point of an actuator according to a structural parameter and a travel speed of the actuator.

[0100] The compensation instruction generation module 103 is configured to generate a displacement compensation instruction for driving an actuator in real time according to the vertical displacement offset and a preset position target value.

[0101] The load disturbance value generation module 104 is configured to drive the driving actuator to output an initial pushing force in response to the displacement compensation instruction, and acquire a load disturbance value of a blade edge of the actuator in real time.

[0102] The thrust level adjustment module 105 is configured to adjust the output thrust of the driving actuator in a disturbance gradient when the load disturbance value exceeds the preset disturbance threshold range.

[0103] The position output consistent adjustment module 106 is configured to dynamically adjust the relative position between the actuating mechanism and the mobile platform based on the output thrust, so that the position output is consistent with the position target value.

[0104] In several embodiments provided in the present application, it should be understood that the disclosed method and system can be implemented in other ways. For example, the system embodiments described above are merely illustrative, for example, the division of the modules is only a logical function division, and actual implementation can have another division manner.

[0105] The modules described as separate components can or can not be physically separated, and the components displayed as modules can or can not be physical units, that is, they can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs.

[0106] In addition, each functional module in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of hardware plus software function module.

[0107] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application.

[0108] The embodiments of the present application can acquire and process related data based on artificial intelligence technology. Among them, artificial intelligence is to use digital computers or machine controlled by digital computers to simulate, extend and expand human intelligence, perceive environment, acquire knowledge and use knowledge to obtain the best results.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for compensating seeding depth based on terrain prediction, characterized in that, The method includes: The terrain and elevation data of the work area ahead are obtained by a controlled object installed on a mobile platform. The curvature variation characteristics of the terrain elevation data are extracted. Based on the structural parameters and travel speed of the actuator, the curvature variation characteristics are converted into the vertical displacement offset of the actuator's contact point. The structural parameters include the inclination angle of the action surface and the mass inertia parameter. The inclination angle of the action surface is measured in real time by an angle sensor, and the mass inertia parameter is preset through calibration tests. The process of converting the curvature variation characteristics into the vertical displacement offset of the actuator's contact point based on the actuator's structural parameters and travel speed includes: The response lag time of the actuator is calculated based on the travel speed of the actuator; Based on the response hysteresis time and the inclination angle of the action surface, the shear resistance phase compensation is performed on the curvature change characteristics to generate the compensated curvature characteristic values; Multiply the compensated curvature feature value by the mass inertia parameter to generate the vertical displacement offset of the actuator contact point; Based on the vertical displacement offset and the preset position target value, a displacement compensation command for driving the actuator is generated in real time. In response to the displacement compensation command, the drive actuator is driven to output initial thrust, and the load disturbance value of the actuator edge is collected in real time. When the load disturbance value exceeds the preset disturbance threshold range, the output thrust of the drive actuator is adjusted according to the disturbance gradient. The relative position of the actuator and the mobile platform is dynamically adjusted based on the output thrust, so that the position output is consistent with the target position value.

2. The sowing depth compensation method based on terrain prediction as described in claim 1, characterized in that, The process of acquiring terrain elevation data of the work area ahead through a controlled object installed on a mobile platform includes: A laser rangefinder is used to scan the work area in front of the mobile platform, and the obtained point cloud data is converted into terrain elevation data.

3. The sowing depth compensation method based on terrain prediction as described in claim 1, characterized in that, The extraction of curvature variation features from the terrain elevation data includes: Calculate the rate of change of slope between adjacent terrain elevation data points; Generate a sequence of terrain curvature radii based on the slope change rate; The abrupt change points in the curvature radius sequence are extracted as curvature change features.

4. The sowing depth compensation method based on terrain prediction as described in claim 1, characterized in that, The step of generating displacement compensation commands for the drive actuator in real time based on the vertical displacement offset and the preset position target value includes: The vertical displacement offset is superimposed on the reference stroke value corresponding to the target position value to generate the compensation stroke value of the drive actuator; The PWM control signal for driving the hydraulic proportional valve is generated based on the compensation stroke value, serving as the displacement compensation command for driving the actuator.

5. The sowing depth compensation method based on terrain prediction as described in claim 4, characterized in that, The preset location target value is determined by selecting a reference depth range according to the type of work object, adjusting the reference depth range based on field calibration tests, and generating the location target value.

6. The sowing depth compensation method based on terrain prediction as described in claim 1, characterized in that, When the load disturbance value exceeds a preset disturbance threshold range, adjusting the output thrust of the drive actuator according to the disturbance gradient includes: The extreme values ​​of load disturbance in the hard clod area and the soft pit area were measured, and the disturbance threshold interval was divided according to the distribution of the extreme values ​​of load disturbance. When the load disturbance value enters the hard soil region, the output thrust is increased according to a linearly increasing function; When the load disturbance value enters the soft soil region, the output thrust is reduced according to the step-decreasing function.

7. The sowing depth compensation method based on terrain prediction as described in claim 1, characterized in that, The step of dynamically adjusting the relative position of the actuator and the moving platform based on the output thrust, so that the position output is consistent with the target position value, includes: The pressing depth of the actuator is detected in real time by a displacement sensor; When the deviation between the pressure depth and the target position value exceeds the tolerance threshold, feedback is provided to readjust the output thrust.

8. A seeding depth compensation system based on terrain prediction, characterized in that, The system includes: The terrain elevation data acquisition module is used to acquire terrain elevation data of the work area ahead through a controlled object installed on a mobile platform; The displacement offset generation module is used to extract the curvature change characteristics of the terrain elevation data, and convert the curvature change characteristics into a vertical displacement offset at the actuator's contact point based on the actuator's structural parameters and travel speed. The structural parameters include the inclination angle of the action surface and mass inertia parameters. The inclination angle of the action surface is measured in real time by an angle sensor, and the mass inertia parameter is preset through calibration tests. The step of converting the curvature change characteristics into a vertical displacement offset at the actuator's contact point based on the actuator's structural parameters and travel speed includes: The response lag time of the actuator is calculated based on the travel speed of the actuator; Based on the response hysteresis time and the inclination angle of the action surface, the shear resistance phase compensation is performed on the curvature change characteristics to generate the compensated curvature characteristic values; Multiply the compensated curvature feature value by the mass inertia parameter to generate the vertical displacement offset of the actuator contact point; The compensation instruction generation module is used to generate displacement compensation instructions for driving the actuator in real time based on the vertical displacement offset and the preset position target value. The load disturbance value generation module is used to respond to the displacement compensation command, drive the drive actuator to output initial thrust, and collect the load disturbance value of the actuator cutting edge in real time. The thrust grading adjustment module is used to adjust the output thrust of the drive actuator according to the disturbance gradient when the load disturbance value exceeds the preset disturbance threshold range. The position output is consistent with the target position value adjustment module, which is used to dynamically adjust the relative position of the actuator and the moving platform based on the output thrust, so that the position output is consistent with the target position value.

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