Cotton picker self-adaptive row alignment and picking head profiling control method and cotton picker self-adaptive row alignment and picking head profiling control system

Abstract

The invention discloses a cotton picker self-adaptive row control and picking head profiling control method and system, and belongs to the technical field of agricultural machinery intelligent control. The method comprises the steps that before picking, the cotton plant row spacing is obtained through a front vision / radar sensor, and the picking head spacing is adjusted through a transverse adjusting mechanism to be matched with a cotton ridge; in the picking process, the height and density of the cotton plants are recognized foresight to set the basic expected depth, real-time feedback of the laser distance measuring sensor is combined, parameters of the self-adaptive PID controller are dynamically adjusted according to the states of the cotton plants, the depth correction amount is calculated, and finally the longitudinal posture of the picking head is controlled. The system comprises a sensing module, a control module, a transverse adjustment execution module and a longitudinal hydraulic servo execution module. According to the cotton picker, the systematic problems of low picking rate, high impurity rate, serious component abrasion and the like caused by inaccurate row alignment before picking and poor depth control in the picking process are integrally solved, the whole-process intelligent operation is realized, and the comprehensive operation efficiency and reliability of the cotton picker are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of intelligent control technology for agricultural machinery, specifically to an adaptive row alignment and picking head contour control method and system for cotton harvesters. Background Technology

[0002] The invention and application of cotton harvesters is a key milestone in the mechanization of cotton production. The core of its operation lies in the picking head, particularly the ability of the picking spindle to maintain an optimal relative position with the cotton plant during rapid movement. This process involves precise control in two dimensions: lateral alignment and longitudinal contouring.

[0003] In terms of lateral row alignment, current operational procedures rely on driver experience. Before operations begin, the spacing between picking heads must be manually adjusted using mechanical linkages or bolts based on the cotton field row spacing, a time-consuming and labor-intensive process. Regarding longitudinal contouring, mainstream technologies currently employ mechanical contouring mechanisms. This technology relies on constant pressure provided by counterweights or hydraulic cylinders, allowing the picking heads to passively move up and down when encountering undulations in the cotton ridges. However, this purely mechanical feedback-based solution has inherent limitations: poor adaptability—its preset pressure cannot intelligently respond to real-time changes in cotton plant height and density in the field; in low-lying or sparse areas, insufficient downward pressure can lead to soil-eroding by the picking heads, while in dense areas, excessive pressure may damage the cotton plants; low control precision—constant pressure prevents the picking depth from being optimized according to working conditions, resulting in missed picking or fluctuations in impurity content; and difficulty in ensuring consistency—differences in the mechanical performance of multiple picking heads lead to uneven overall operational results.

[0004] Therefore, there is a need in this field for a technical solution that can intelligently and precisely control the working position of the picking head to adapt to the complex and ever-changing cotton field environment. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing mechanical contouring methods and provide an adaptive row and picking head contouring control method and system for cotton harvesters. This system can sense the cotton plant status in real time and automatically and accurately adjust the spacing of the picking heads and the picking depth of the picking spindles, thereby achieving synergistic optimization of high harvesting efficiency, low impurity content and long component life.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: In a first aspect, the present invention provides a method and system for adaptive row alignment and picking head contour control of a cotton harvester, comprising the following steps: S10: Obtain cotton plant status information of the cotton ridge ahead through the forward sensing unit. The status information includes cotton plant row spacing, average cotton plant height and density. S20: Based on the cotton plant row spacing, the lateral distance between each picking head is adjusted by the lateral adjustment mechanism to match the cotton ridge row spacing; S30: After the harvesting operation is started, based on the average height and density of the cotton plants, a preset mapping table is queried to determine the basic expected harvesting depth; S40: Obtain the real-time distance between the spindle and the ground through the real-time feedback sensing unit; S50: Based on the deviation between the real-time distance and the basic expected picking depth, the depth correction amount is calculated using an adaptive PID controller, wherein the proportional, integral, and derivative parameters of the adaptive PID controller are dynamically adjusted according to the cotton plant status information; S60: Add the basic expected picking depth to the depth correction amount to obtain the final expected picking depth; S70: Based on the final desired picking depth, the longitudinal position of the picking head is controlled by a longitudinal hydraulic servo system.

[0007] Secondly, the present invention provides an adaptive row alignment and picking head contour control method and system for implementing the above-mentioned method for a cotton harvester, comprising: The sensing module includes a forward-facing vision or radar sensor for forward sensing, and a laser rangefinder sensor mounted on the picking head for real-time feedback. Control module: electrically connected to the sensing module, configured to execute steps S30 to S60 of the adaptive contour control method; Lateral adjustment execution module: The lateral adjustment execution module may optionally be a ball screw pair driven by a servo motor or a hydraulic cylinder. Each picking head assembly is mounted on the lateral guide rail of the frame via a slider or slide rail;

[0008] Hydraulic servo actuator module: electrically connected to the control module, including an electro-hydraulic servo valve, a hydraulic cylinder and a displacement sensor, used to receive commands from the control module and drive the picking head to move.

[0009] Preferably, the control module includes: a row control unit for processing row spacing information and controlling the lateral adjustment execution module; a high-level decision unit for deciding the final desired picking depth based on cotton plant height and density information; and a low-level servo controller for controlling the longitudinal hydraulic servo execution module.

[0010] Preferably, the control module is further configured to: first, invoke the row alignment control logic, and based on the stable cotton plant row spacing signal obtained by the look-ahead sensing unit, drive the lateral adjustment execution module to complete the preset picking head spacing; after the row alignment is completed, automatically or by receiving an instruction, switch to the adaptive contour control mode, and enter continuous longitudinal depth closed-loop control. The two modes share sensing information and are coordinated and managed by the same controller.

[0011] Preferably, the dynamic adjustment strategy is as follows: when the cotton plants are identified as being short and sparse, the proportional gain and derivative gain of the adaptive PID controller are dynamically adjusted.

[0012] Preferably, the underlying servo controller also incorporates the cotton harvester's forward speed as a feedforward signal and the system pressure signal as a safety compensation signal.

[0013] Preferably, the drive end of the lateral adjustment execution module is connected to the picking head assembly to drive it to move laterally along the guide rail. The module also includes a displacement sensor for detecting the actual lateral position of the picking head, forming a closed-loop control.

[0014] The present invention has the following beneficial effects: Compared with the prior art, the beneficial effects of the present invention are: Through intelligent contouring, the picking spindle can closely fit cotton plants of different heights, significantly improving the picking effect, especially for low-growing cotton plants, increasing the picking rate and reducing missed picking losses.

[0015] Precise distance control can prevent the spindle from touching the ground and getting soil, greatly reducing the mixing of foreign fibers such as soil and plastic film, lowering the impurity content and improving the quality of cotton lint.

[0016] It significantly reduces hard contact and wear between the spindle and cotton removal discs and the ground, enhances component life, extends the replacement cycle of these core wear parts, and reduces operating costs.

[0017] The system can automatically identify the cotton field environment and adjust the control strategy, reducing the reliance on the driver's operating experience and improving the overall automation level and operational stability of the cotton harvester.

[0018] The traditional manual alignment and experience-based contouring operation mode has been innovated into an integrated automatic operation mode that combines automatic and precise alignment with adaptive intelligent contouring, which significantly reduces the difficulty of operation and improves the efficiency and accuracy of job preparation. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a block diagram of the overall structure of the adaptive contouring control system in an embodiment of the present invention; Figure 2 This is a flowchart of the adaptive contour control method in an embodiment of the present invention; Figure 3 This is a schematic diagram of the row control logic in an embodiment of the present invention; Figure 4 This is a schematic diagram of the adaptive control logic of the high-level decision-making unit in an embodiment of the present invention; Figure 5 This is an installation diagram of the laser rangefinder sensor in an embodiment of the present invention; Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] See Figure 1 The system is arranged on the cotton harvester as follows: a front-mounted vision camera or lidar is installed on the top of the cab or the front guardrail, covering the cotton ridges ahead. Multiple laser rangefinders are installed on each picking head, pointing towards the ground below the tip of the picking spindle. The controller (using a high-performance PLC or industrial-grade embedded computer) is installed in a waterproof electrical control box. The hydraulic cylinders of the hydraulic servo actuator module are connected to the lifting arm of the original picking head, and in parallel with the existing mechanical contouring mechanism.

[0023] See Figure 2 The method and process are as follows: When the cotton harvester enters the cotton field to prepare for operation, the controller initiates the row alignment program. The front-mounted vision camera identifies the clear outline of the cotton plants and calculates the average row spacing (Row_Spacing) using an image processing algorithm. The controller reads the current lateral position of each picking head and calculates the displacement and direction that each picking head needs to move. Subsequently, the controller sends commands to the lateral adjustment execution module to drive the picking heads to move smoothly. Linear encoders mounted on the lateral guide rail provide real-time position feedback, forming a closed loop, until the error between the spacing of all picking heads and Row_Spacing is less than ±2cm. After row alignment is completed, the touchscreen displays 'Row alignment complete, operation can begin'. The driver moves the vehicle forward, and the system automatically enters the adaptive contour control mode. When the cotton harvester enters the cotton field and the adaptive contour control mode is activated, the controller reads data from the front-end sensors and uses image processing or point cloud analysis algorithms to identify the average height H_avg and density Density of the cotton plants in front. Based on preset rules (e.g., H_avg < 40cm and Density < 50% is considered a "low and sparse" state), the controller queries the mapping table to obtain L_desired_base = 8cm.

[0024] Simultaneously, the controller reads the L_real value from the laser rangefinder. The deviation e is calculated as: e = L_real - 8cm.

[0025] Since the current state is "low and sparse," the adaptive PID controller adopts a conservative strategy, adjusting its parameters to: Kp=0.5, Ki=0.1, Kd=0.2 (smaller than the normal state's Kp=1.2, Ki=0.2, Kd=0.5). Based on the adjusted parameters and the deviation e, the smoothing correction ΔL is calculated.

[0026] Ultimately, L_desired_final = 8cm + ΔL. This instruction is then sent to the underlying servo controller.

[0027] The underlying servo controller converts distance commands into displacement commands for the hydraulic cylinders, and forms a closed loop through built-in displacement sensors to drive the harvesting head to move precisely to the target position. During this process, the underlying controller also receives the machine's forward speed signal for feedforward compensation, making the movement smoother. After completing this control operation, the laser rangefinder continues to transmit signals for the next distance adjustment, enabling real-time adjustment of the harvesting head during operation.

[0028] The specific implementation method adopted in this invention is as follows: The entire implementation method can be divided into two main stages: the operation preparation stage and the adaptive contouring stage. In the operation preparation stage, after the cotton harvester enters the cotton field, the system first obtains the row spacing of the cotton plants in front through the front vision or radar sensor; the control module calculates the lateral adjustment amount required for each picking head based on this, and drives the lateral adjustment mechanism (such as hydraulic cylinder) to move the picking head until its spacing is precisely matched with the row spacing of the cotton ridge, thus completing the automatic row alignment.

[0029] After entering the adaptive contouring stage, the system initiates a continuous closed-loop control cycle. This cycle is based on cotton plant height and density information sensed by front-end sensors, as well as real-time distance feedback from laser rangefinders. The core process is as follows: the control module dynamically switches PID control parameters according to the cotton plant status (e.g., dense and tall plants, sparse and short plants), calculates the desired picking depth and correction amount in real time through an adaptive algorithm, and performs feedforward compensation in conjunction with the cotton harvester speed; the underlying controller then converts the depth command into a high-precision displacement signal, driving the hydraulic servo system to quickly and smoothly adjust the picking head height, while integrating pressure monitoring to achieve overload protection. This cycle runs continuously at millisecond intervals, ensuring that the picking spindle maintains the optimal operating depth in complex field environments.

[0030] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method and system for adaptive row alignment and picking head contour control of a cotton harvester, characterized in that, The method comprises the following steps: obtaining the cotton plant state information of the front cotton ridge through a forward-looking perception unit, the state information including the cotton plant row spacing, the average height of the cotton plant, and the density of the cotton plant; adjusting the lateral distance between each picking head through a lateral adjustment mechanism based on the cotton plant row spacing so as to match the cotton ridge row spacing; after the picking operation is started, querying a preset mapping table based on the average height of the cotton plant and the density of the cotton plant to determine a basic expected picking depth; obtaining the real-time distance between the picking cylinder and the ground through a real-time feedback perception unit; calculating a depth correction amount by using an adaptive PID controller based on the deviation between the real-time distance and the basic expected picking depth, wherein the proportional, integral, and differential parameters of the adaptive PID controller are dynamically adjusted according to the cotton plant state information; adding the basic expected picking depth and the depth correction amount to obtain a final expected picking depth; controlling the longitudinal pose of the picking head through a longitudinal hydraulic servo system based on the final expected picking depth.

2. The method of claim 1, wherein, In the step of "adjusting the lateral distance between each picking head through a lateral adjustment mechanism based on the cotton plant row spacing so as to match the cotton ridge row spacing", the cotton plant row spacing is compared with the current picking head spacing, the lateral adjustment amount required by each picking head is calculated, and the lateral adjustment mechanism is driven to perform adjustment until the error between the actual spacing and the target row spacing is less than a set threshold.

3. The method of claim 1, wherein, The dynamic adjustment strategy is as follows: when it is identified that the cotton plant is in a low and sparse state, the proportional gain Kp and the differential gain Kd of the adaptive PID controller are dynamically adjusted; the final expected distance is converted into an expected displacement of the hydraulic cylinder; based on the expected displacement and the actual displacement of the hydraulic cylinder displacement sensor, the electro-hydraulic servo valve is driven by the underlying servo controller to control the movement of the hydraulic cylinder, and the forward speed of the cotton picker is introduced as a feedforward compensation signal.

4. A method and system for implementing adaptive row alignment and profile control of a cotton picker with a picking head, according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: a perception module comprising a front sensor for forward-looking perception and a laser ranging sensor installed on the picking head for real-time feedback; a control module electrically connected with the perception module and configured to execute the adaptive row-by-row and profiling control method; a lateral adjustment execution module electrically connected with the control module and used for driving each picking head to move laterally according to the cotton plant row spacing; a hydraulic servo execution module electrically connected with the control module and used for driving the picking head to move longitudinally according to the final expected picking depth.

5. The system of claim 4, wherein, The lateral adjustment execution module is a lead screw mechanism driven by a servo motor or an independent hydraulic cylinder. The control module comprises a row control unit for processing row spacing information and controlling the lateral adjustment execution module, a high-level decision unit for deciding the final expected picking depth according to the height and density information of the cotton plant, and an underlying servo controller for controlling the longitudinal hydraulic servo execution module. The front sensor is a vision camera or a laser radar. The hydraulic servo execution module comprises an electro-hydraulic servo valve, a hydraulic cylinder, and a displacement sensor for detecting the displacement of the piston rod of the hydraulic cylinder.

6. A cotton harvester characterized by, The cotton picker is equipped with the adaptive row-by-row and picking head profiling control method and system according to any one of claims 4 to 5.

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