Path tracking control method for electric knee-bending micro-cultivator based on compensation of articulation angle

Abstract

The application discloses a kind of electric kneeing micro-cultivator path tracking control methods based on hinge angle compensation, method includes: obtaining micro-cultivator real-time position information and heading information, actual kneeing angle is obtained using angle sensor;Based on preset target path, the lateral deviation and heading deviation of current micro-cultivator deviating from target path are calculated;According to lateral deviation, heading deviation and soft soil dynamics slip compensation, the target kneeing angle required for micro-cultivator to return to target path is calculated and amplitude limiting processing is carried out;The kneeing angle of amplitude limiting processing is compared with real-time actual kneeing angle to obtain angle error, and steering control dead zone filtering is carried out, to generate control instruction dynamic adjustment steering actuator, so that actual kneeing angle approaches target kneeing angle.The application compensates the motion hysteresis of kneeing mechanism and soft soil sideslip, eliminates the frequent shock caused by mechanical clearance, improves the autonomous navigation stability, mechanical life and path tracking accuracy of micro-cultivator in complex farmland environment.

Description

Technical Field

[0001] This invention belongs to the field of intelligent agricultural machinery technology, specifically relating to a path tracking control method for an electric folding tiller based on articulation angle compensation. Background Technology

[0002] To reduce turning radius and improve space utilization in narrow farmland, articulated chassis have been applied in the design of mini tillers. The articulated chassis achieves steering through the relative folding and hinge of the first and second vehicle bodies, offering significant engineering advantages such as a small turning radius, high overlap of four-wheel turning trajectories, and strong adaptability to complex terrain. However, in autonomous navigation path tracking control, the articulated chassis faces the following pressing industry technical bottlenecks and physical constraints that need to be addressed.

[0003] First, the folding chassis steering system is a typical "nonholonomic constraint" system. In actual field autonomous navigation, after the main control unit issues a steering command, the steering actuator requires a certain physical response time to push the vehicle body fold. This prevalent mechanical lag and kinematic delay cause the vehicle to easily generate severe system overshoot and deviations when changing paths, making sharp turns, or making minor adjustments on straightaways. This manifests as violent swaying and unstable zigzag patterns on the actual vehicle trajectory.

[0004] Second, the existing intelligent agricultural machinery autonomous navigation path tracking algorithm lacks real-time closed-loop perception of the actual relative deflection angle (i.e., the actual bending angle γ) between the first and second vehicle bodies. Under such circumstances, disturbances caused by mechanical gaps and uneven ground cannot be eliminated by the closed loop, which greatly reduces the steady-state accuracy of path tracking.

[0005] Third, existing path tracking control strategies are generally based on the ideal kinematic assumption that tires do not skid. Once they enter soft ground, the pure kinematic control will fail due to ground slippage, leading to accumulated tracking errors.

[0006] Fourth, to obtain sufficient steering torque, electric slack tillers generally incorporate reduction actuators such as worm gear steering mechanisms. However, such mechanical structures inevitably exhibit backlash (i.e., return error) during frequent forward and reverse switching. If the navigation circuit directly implements continuous high-frequency fine-tuning feedback, the steering motor will experience high-frequency twitching (oscillation) within the backlash dead zone. This not only fails to smoothly correct the path but also leads to severe motor overheating, accelerated wear of transmission gears, and a significant shortening of the machine's overall mechanical lifespan.

[0007] Finally, the tiller experiences high-frequency, high-amplitude vibrations in its drive system and severe ground jolting during operation. Under prolonged and intense vibration and stress deformation, the coaxially mounted angle sensor inevitably experiences physical drift in its initial zero position, causing the tiller to consistently tilt to one side when traveling on straight roads, making it impossible to maintain long-term navigational stability. Summary of the Invention

[0008] The main objective of this invention is to overcome the shortcomings and deficiencies of the prior art and to propose a path tracking control method for an electric folding tiller based on hinge angle compensation.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] The path tracking control method for an electric folding tiller based on articulation angle compensation includes the following steps:

[0011] S1. Obtain the current real-time position and heading information of the micro-tiller's reference point, and simultaneously use the angle sensor installed at the vehicle's articulation point to obtain the real-time actual bending angle between the first and second vehicle bodies. ;

[0012] S2. Based on the real-time position information, heading information, and preset target path of the tiller reference point, determine the target path reference point and its tangent direction angle, and calculate the lateral deviation d and heading deviation of the current tiller position from the target path. ;

[0013] S3. Based on the lateral deviation d and the heading deviation Based on the vehicle kinematics model and soft soil dynamics slip compensation, the target bending angle required for the mini-tiller to return to the target path was calculated. ;

[0014] S4. Limit the target bending angle according to the bending angle range allowed by the mechanical structure of the micro-tiller;

[0015] S5. Compare the bend angle after the amplitude limiting process with the actual bend angle in real time. The angle error 'e' is obtained through comparison, and dead zone filtering for steering control is performed. Control commands are then generated to dynamically adjust the steering actuator, ensuring the real-time actual bend angle is correct. Approaching the target bending angle The steps S1 to S5 are executed repeatedly to make the real-time actual bending angle track the target bending angle after the width limit, and to make the micro-tiller reference point track the preset target path.

[0016] The present invention also includes an electric folding tiller, comprising a first body, a second body, a main hinge pin connecting the first body and the second body, a power battery, a steering actuator, a combined navigation and positioning terminal, a main control unit, and an angle sensor;

[0017] The angle sensor is coaxially mounted at the main hinge pin.

[0018] The angle sensor, the integrated navigation and positioning terminal, and the steering actuator are all connected to the main control unit for communication.

[0019] When the electric folding tiller performs autonomous navigation operations, the path tracking control method for the electric folding tiller based on hinge angle compensation provided by this invention is adopted.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] 1. This invention effectively suppresses the overshoot phenomenon of the drawing dragon; by introducing a coaxial angle sensor to provide real-time feedback on the actual bending angle of the front and rear vehicle bodies, a fast attitude closed loop is formed with the target bending angle calculated by the navigation outer ring, which effectively compensates for the inherent motion response lag of the bending mechanism and greatly improves the smoothness of the vehicle when switching paths.

[0022] 2. This invention significantly improves the accuracy of operations in soft farmland; through dynamically adjusted adaptive look-ahead distance and online estimation of soft soil dynamic slip compensation, the control method can perceive and correct tire slippage caused by soil with varying characteristics in real time, ensuring the steady-state tracking accuracy of the micro-tiller in complex and harsh terrains such as paddy fields and soft dry land in the south.

[0023] 3. By embedding a steering control dead zone filter in the feedback loop, this invention automatically isolates the high-frequency micro-amplitude oscillations of the system caused by the mechanical backlash (backlash error) of the worm gear steering mechanism, prevents the steering motor from overheating, improves the field engineering reliability of the system hardware, and significantly extends the life of the steering mechanism and motor.

[0024] 4. This invention achieves long-term maintenance-free control of the control system; the built-in zero-position adaptive calibration logic can take advantage of the gaps in the long straight-line travel of the micro-tiller to automatically correct the zero-point drift of the sensor caused by severe vibration in the field, eliminating the tedious process of frequent manual disassembly and calibration of hardware. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the electric folding tiller in the embodiment.

[0026] Figure 2 This is a partially enlarged schematic diagram of the angle sensor mounting structure at the hinge in the embodiment.

[0027] Figure 3 This is a flowchart of the path tracking control method for an electric tilting micro-tiller based on hinge angle compensation according to the present invention.

[0028] Explanation of reference numerals: 1-Power battery; 2-Second vehicle body; 3-Angle sensor; 4-Hinge mechanism; 5-First vehicle body; 6-Steering motor; 7-Main control unit; 8-Coupling; 9-Main hinge pin; 10-Combined navigation and positioning terminal; 11-Steering actuator; 12-Shaft sleeve structure; 13-Fixed bracket. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0030] Example; This example uses, as follows Figure 1 The method of the present invention will be described in detail using the electric folding tiller shown as an example. In this embodiment, the electric folding tiller specifically includes a first vehicle body 5, a second vehicle body 2, an articulation mechanism 4, a power battery 1, a steering actuator 11, a combined navigation and positioning terminal 10, a main control unit 7, and an angle sensor 3.

[0031] The angle sensor, positioning terminal, and steering actuator are all communicatively connected to the main control unit. The angle sensor is a non-contact coaxial hinged angle measurement mechanism; in this embodiment, the first vehicle body 5 is the front chassis, and the second vehicle body 2 is the rear chassis; in actual implementation, the physical front-rear positions of the first vehicle body 5 and the second vehicle body 2 can be completely interchanged. The hinge mechanism 4 includes a main hinge pin 9 that passes through the first vehicle body 5 and the second vehicle body 2. The first and second vehicle bodies rotate relative to each other with this pin as the center line to achieve zigzag steering. The angle sensor 3 is coaxially mounted on the axis of the main hinge pin.

[0032] like Figure 2 As shown, a non-standard bushing structure 12 is coaxially sleeved at the end of the main hinge pin. The non-standard bushing structure remains relatively stationary with the first vehicle body 5 during steering operations. A 6mm optical shaft structure is coaxially machined or fixed on the top of the non-standard bushing structure as a stationary reference end for coaxial angle input.

[0033] The angle sensor is fixed to the second body 2 by a high-rigidity sheet metal bracket 13. When the tiller performs steering operations, the angle sensor 3 rotates synchronously with the second body 2 relative to the first body 5.

[0034] Under the premise of ensuring a certain degree of coaxiality, the 6mm optical shaft structure at the top of the non-standard bushing structure is mechanically connected to the input shaft of the angle sensor 3 through a flexible coupling 8 (such as an elastic bellows coupling) with anti-vibration and correction functions.

[0035] With the above structure, when the tiller turns, the first body 5 and the second body 2 undergo relative angular deflection. Since the angle sensor 3 rotates with the second body 2, while the optical shaft structure axially connected to it remains stationary with the first body 5, the input shaft of the angle sensor 3 rotates coaxially relative to the sensor housing, thus enabling real-time measurement of the actual bending angle. Real-time, coaxial, and high-precision measurement of the (angle between the front and rear vehicle bodies). Thanks to the use of a flexible coupling 8, the impact loads transmitted from the plow or tracks during tillage are effectively isolated, protecting the mechanical bearings of the sensor.

[0036] The main control unit has a built-in zero-position self-calibration module, which is used by the positioning terminal to determine that the tiller is traveling in a straight line and that the lateral deviation d and the heading deviation are within the straight line. When the value remains within the preset threshold, the system automatically reads the current physical output value of the angle sensor and updates it to the absolute zero reference value at the system software level.

[0037] The steering actuator includes a steering motor 6 and a worm gear steering mechanism;

[0038] The main control unit is based on the target bending angle. With real-time actual bending angle The angle error e generates a PWM drive signal, which controls the steering motor to move, and then pushes the first car body and the second car body to fold relative to each other through the worm gear steering mechanism.

[0039] To ensure the driving safety of the mini-tiller in autonomous navigation mode and avoid software oversaturation or hardware overload damage, the effective measurement and control range of the flexing angle of the electric slack-down mini-tiller is set between -30° and 30°, where -30° represents the maximum permissible flexing angle on one side of the vehicle, and 30° represents the maximum permissible flexing angle on the other side. The above angle range is only a preferred range for this embodiment; in practical applications, it can be adjusted according to vehicle structural dimensions, steering mechanism travel, and safety requirements.

[0040] The main control unit 7 has a two-level safety limiting protection logic deployed inside:

[0041] Active amplitude limiting protection at the software level: In automatic navigation mode, the system's main control unit 7 monitors the bend angle in real time via angle sensor 3. Once the target bend angle command is obtained from the outer or middle loop algorithm... Exceeding the set safety threshold physical limit value (i.e. The main control unit 7 will forcibly execute the dynamic saturation cutoff logic to lock the target angle command at... or The boundary value must never exceed this safety threshold to send a drive signal to the steering motor of the inner ring execution layer. That is:

[0042] like Then let ;like Then let ;like Then keep constant;

[0043] Passive safety protection at the hardware level: Symmetrically reinforced rigid physical limit blocks are installed on the mechanical structure at the hinge joints. When the first vehicle body 5 and the second vehicle body 2 fold relative to each other to reach their physical limit... At this time, the physical limit stop implements hard contact limit. As the last line of hardware-level safety protection, it is used to prevent the steering motor from continuously outputting excessive torque under extreme conditions such as software abnormalities, algorithm failures, or sensor malfunctions, which could lead to mechanical structure breakage or overload burnout of the steering motor due to stall.

[0044] In this embodiment, the electric folding tiller employs a path tracking control method based on hinge angle compensation when performing autonomous navigation operations. Figure 3 As shown, the method includes the following steps:

[0045] S1. Obtain the current real-time position and heading information of the micro-tiller's reference point, and simultaneously use the angle sensor installed at the vehicle's articulation point to obtain the real-time actual bending angle between the first and second vehicle bodies. ;

[0046] In this embodiment, specifically:

[0047] Establish a geodetic coordinate system and preset the navigation target path according to the task.

[0048] Real-time geodetic coordinates of the micro-tiller's reference point are obtained through a BeiDou / GPS integrated navigation and positioning terminal. and the current real-time heading angle of the vehicle body to which the reference point belongs. (i.e., the angle between the current driving direction of the reference point's vehicle body and the X-axis of the coordinate system), the real-time actual bending angle between the first and second vehicle bodies is obtained using an angle sensor at the hinge pin. To ensure the continuity of positioning data in environments with weak GNSS signals, such as when fruit trees block the view or greenhouse edges, the main control unit 7 incorporates a Kalman filter algorithm to perform real-time dead reckoning by fusing data from the positioning terminal and the inertial measurement unit (IMU).

[0049] S2. Based on the real-time position information, heading information, and preset target path of the tiller reference point, determine the target path reference point and its tangent direction angle, and calculate the lateral deviation d and heading deviation of the current tiller position from the target path. ;

[0050] In this embodiment, specifically:

[0051] Set reference point for micro-tiller The reference point is the vehicle's heading. The coordinates of the target path reference point are The tangent direction angle at the target path reference point is Calculate the signed lateral deviation d and the heading deviation. The calculation formula is:

[0052] ;

[0053] ;

[0054] When observing along the direction of travel along the target path, the reference point of the micro-tiller is located on the right side of the target path. When positive, it is located to the left of the target path. Negative; This is the angle normalization function.

[0055] Step S2 also includes zero-point self-calibration of the angle sensor, specifically:

[0056] Due to the intense vibrations during farmland cultivation, the physical zero position of the angle sensor is prone to drift after long-term operation. Therefore, when the integrated navigation and positioning terminal determines that the tiller is in a high-precision straight-line driving state, and the calculated lateral deviation... and heading deviation Continuously maintain at a preset threshold (e.g.) If the time exceeds a preset time N (e.g., N=5s), it is determined that the current tiller is in an absolutely straight-line driving state. It immediately and automatically reads the current physical reading of the angle sensor and updates it to the absolute zero reference value at the system software level, thereby dynamically eliminating the systematic bias error to one side caused by hardware deformation.

[0057] S3. Based on the lateral deviation d and the heading deviation Based on the vehicle kinematics model and soft soil dynamics slip compensation, the target bending angle required for the mini-tiller to return to the target path was calculated. ;

[0058] In this embodiment, the target bending angle is calculated. Specifically, the following steps are included:

[0059] Determine the look-ahead distance L; to overcome the contradiction between slow approach to large deviations and straight-line oscillations caused by a fixed look-ahead distance, the look-ahead distance L in this embodiment is an adaptive time-varying variable, dynamically iteratively calculated based on the current real-time driving speed v of the micro-tiller and the absolute value of the lateral deviation d. Its adaptive function expression is:

[0060] ;

[0061] in, This is the vehicle speed adjustment coefficient. This is the deviation adjustment coefficient. To ensure the minimum physical lower bound of the look-ahead distance for geometrically solvable systems;

[0062] Based on the look-back distance L, calculate the target steering curvature K required for the vehicle's return path:

[0063] ;

[0064] in, This is the weighting coefficient for the lateral deviation.

[0065] Based on the geometric kinematics model of a micro-tiller, the target is steered by curvature. Converted to theoretical kinematic target bending angle :

[0066] ;

[0067] The distance from the main articulation pin to the center of the front axle of the vehicle body is: The distance from the main hinge pin to the center of the rear axle is The actual bend angle is ;

[0068] Then, soft soil dynamic slip compensation is performed, specifically as follows:

[0069] Because the soil in paddy fields or soft, dry land in the south is highly prone to nonlinear sideslip of the tires, pure kinematic calculations in the field can lead to cumulative vehicle yaw. Therefore, the actual heading angular velocity of the vehicle fed back by the integrated navigation and positioning terminal is crucial. Theoretical angular velocity derived from theoretical kinematic models Online real-time differential calculations were performed to determine the adaptive slip compensation amount of the micro-tiller in soft soil conditions. :

[0070] ;

[0071] Finally, the slip compensation amount Superimposed on the theoretical kinematic target bend angle obtained from the transformation based on the geometric kinematic model Up, to obtain the final target bend angle :

[0072] ;

[0073] S4. Limit the target bend angle according to the allowable bend angle range of the micro-tiller's mechanical structure; in this embodiment, after calculating the target bend angle, a limit protection judgment is performed, specifically as follows:

[0074] like Then let ;like Then let ;like Then keep Unchanged; this determination ensures that subsequent instructions are entirely within the safe limits allowed by the mechanical structure.

[0075] S5. The bend angle after the amplitude limiting process With real-time actual bending angle The angle error e is obtained through comparison. Based on the angle error e, the steering control dead zone is filtered, and control commands are generated to dynamically adjust the steering actuator, thereby adjusting the real-time actual bend angle. Approaching the target bending angle The steps S1 to S5 are executed repeatedly to make the real-time actual bending angle track the target bending angle after the width limit, and to make the micro-tiller reference point track the preset target path.

[0076] In this embodiment, specifically:

[0077] The main control unit reads the real-time actual bending angle between the first and second bodies of the tiller from the angle sensor. Calculate the target bending angle With real-time actual bending angle angular error between :

[0078] ;

[0079] Since worm gear steering systems inevitably experience physical backlash (reverse mechanical backlash) during frequent forward and reverse rotation, a steering control dead-zone filter is pre-installed in the main control unit 7 to prevent the steering motor from experiencing high-frequency micro-oscillations within the backlash dead zone. The following de-squeezing steps are implemented:

[0080] Preset steering dead zone angle threshold (In this embodiment, it is set to 0.5°), for the calculated angle error Perform dead zone determination:

[0081] like If the current angle error is determined to be completely within the mechanical backlash range of the worm gear steering mechanism, the main control unit will forcibly block the drive output, maintain the current position of the steering motor at rest, and not issue any micro-adjustment signals.

[0082] When the angle error exceeds the dead zone, that is Based on angle error A PWM drive signal is generated to drive the steering motor. The steering motor, through a worm gear steering mechanism, causes the first and second vehicle bodies to fold and twist relative to each other (i.e., bend over), dynamically adjusting the vehicle's mechanical attitude until the actual bend angle is determined in real time. It converges quickly and smoothly to the target bend angle. Nearby. Repeat steps S1 to S5 to make the real-time actual bending angle track the target bending angle after the amplitude limit, and make the micro-tiller reference point track the preset target path.

[0083] In addition, in this embodiment, the inner-loop PID control algorithm built into the main control unit has an anti-windup function. When the steering motor encounters a large clod of soil or a deep mud pit in the field, causing the drive signal to reach the maximum PWM limit output, the algorithm automatically stops the accumulation of the internal integrator, thereby preventing the tiller from experiencing violent tail-swing oscillation due to integral saturation when it rushes out of the obstacle or mud pit.

[0084] It should also be noted that, in this specification, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0085] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A path tracking control method for an electric folding tiller based on hinge angle compensation, characterized in that, Includes the following steps: S1. Obtain the current real-time position and heading information of the micro-tiller's reference point, and simultaneously use the angle sensor installed at the vehicle's articulation point to obtain the real-time actual bending angle between the first and second vehicle bodies. ; S2. Based on the real-time position information, heading information, and preset target path of the tiller reference point, determine the target path reference point and its tangent direction angle, and calculate the lateral deviation d and heading deviation of the current tiller position from the target path. ; S3. Based on the lateral deviation d and the heading deviation Based on the vehicle kinematics model and soft soil dynamics slip compensation, the target bending angle required for the mini-tiller to return to the target path was calculated. ; S4. Limit the target bending angle according to the bending angle range allowed by the mechanical structure of the micro-tiller; S5. Compare the bend angle after the amplitude limiting process with the actual bend angle in real time. The angle error 'e' is obtained through comparison, and dead zone filtering for steering control is performed. Control commands are then generated to dynamically adjust the steering actuator, ensuring the real-time actual bend angle is correct. Approaching the target bending angle The steps S1 to S5 are executed repeatedly to make the real-time actual bending angle track the target bending angle after the width limit, and to make the micro-tiller reference point track the preset target path.

2. The path tracking control method for an electric folding tiller based on articulation angle compensation according to claim 1, characterized in that, Step S1 is as follows: Establish a geodetic coordinate system and preset the navigation target path according to the task. Real-time geodetic coordinates of the micro-tiller's reference point are obtained via a BeiDou / GPS integrated navigation and positioning terminal. and the current real-time heading angle of the vehicle body to which the reference point of the mini tiller belongs. The real-time actual bending angle between the first and second vehicle bodies is obtained using an angle sensor at the hinge pin. .

3. The path tracking control method for an electric tilting tiller based on hinge angle compensation according to claim 1, characterized in that, In step S2, the lateral deviation d and the heading deviation The calculation is as follows: Let the coordinates of the reference point of the mini-tiller be... The reference point is the vehicle's heading. The coordinates of the target path reference point are The tangent direction angle at the target path reference point is lateral deviation and heading deviation They are respectively: ； ； When observing along the direction of travel along the target path, the reference point of the micro-tiller is located on the right side of the target path. When positive, it is located to the left of the target path. Negative; Angle normalization function; Step S2 also includes zero-point self-calibration of the angle sensor, specifically: When the integrated navigation and positioning terminal determines that the tiller is in a high-precision straight-line driving state, and the calculated lateral deviation... and heading deviation When the tiller is continuously maintained within the preset threshold for more than a preset time N, it is determined that the tiller is in an absolutely straight-line driving state. The current physical reading of the angle sensor is immediately and automatically read and updated to the absolute zero reference value at the system software level, thereby dynamically eliminating the error of systematic lateral tilt caused by hardware deformation.

4. The path tracking control method for an electric folding tiller based on articulation angle compensation according to claim 1, characterized in that, In step S3, the target bending angle is calculated. Specifically, the following steps are included: The look-ahead distance L is determined as an adaptive time-varying variable, dynamically iteratively calculated based on the current real-time driving speed v of the tiller and the absolute value of the lateral deviation d. Its adaptive function expression is as follows: ； in, This is the vehicle speed adjustment coefficient. This is the deviation adjustment coefficient. To ensure the minimum physical lower bound of the look-ahead distance for geometrically solvable systems; Based on the look-ahead distance L, calculate the target steering curvature K required for the vehicle's return path: ； in, This is the weighting coefficient for the lateral deviation; Based on the geometric kinematics model of a micro-tiller, the target is steered by curvature. Converted to theoretical kinematic target bending angle : ； The distance from the main articulation pin to the center of the front axle of the vehicle body is: The distance from the main hinge pin to the center of the rear axle is The actual bend angle is ; Then, soft soil dynamic slip compensation is performed, specifically as follows: The actual angular velocity of the vehicle fed back by the integrated navigation and positioning terminal Theoretical angular velocity derived from theoretical kinematic models Online real-time differential calculations were performed to determine the adaptive slip compensation amount of the micro-tiller in soft soil conditions. : ； Finally, the slip compensation amount Superimposed on the theoretical kinematic target bend angle obtained from the transformation based on the geometric kinematic model Up, to obtain the final target bend angle : 。 5. The path tracking control method for an electric tilting tiller based on hinge angle compensation according to claim 1, characterized in that, In step S4, the limiting process is specifically as follows: After calculating the target bending angle, a limiting protection judgment is performed, specifically as follows: like Then let ;like Then let ;like Then keep constant; This determination ensures that subsequent instructions are entirely within the safe limits allowed by the mechanical structure.

6. The path tracking control method for an electric tilting tiller based on articulation angle compensation according to claim 1, characterized in that, Step S5 is as follows: Real-time reading of the actual bending angle between the first and second bodies of the tiller, fed back by the angle sensor. Calculate the bend angle after the amplitude limiting process. With real-time actual bending angle angular error between : ； Perform steering control dead zone filtering, specifically as follows: Preset steering dead zone angle threshold Regarding the calculated angle error Perform dead zone determination: like If the current angle error is determined to be completely within the mechanical backlash range of the worm gear steering mechanism, the output of control commands to the steering actuator will be forcibly stopped. When the angle error exceeds the dead zone, that is Based on angle error Generate PWM drive signals to dynamically adjust the steering actuator.

7. An electric folding tiller, characterized in that, It includes a first vehicle body, a second vehicle body, a main articulation pin connecting the first vehicle body and the second vehicle body, a power battery, a steering actuator, a combined navigation and positioning terminal, a main control unit, and an angle sensor; The angle sensor is coaxially mounted at the main hinge pin. The angle sensor, the integrated navigation and positioning terminal, and the steering actuator are all connected to the main control unit for communication. When the electric folding tiller performs autonomous navigation operations, the path tracking control method for the electric folding tiller based on hinge angle compensation as described in any one of claims 1-6 is adopted.

8. An electric folding tiller according to claim 7, characterized in that, The angle sensor is a non-contact coaxial hinge angle measurement mechanism; A non-standard bushing structure is coaxially sleeved at the end of the main hinge pin. The non-standard bushing structure remains relatively stationary with the first vehicle body when turning. A light shaft structure extends coaxially from the top of the non-standard bushing structure. The angle sensor is mounted on the second vehicle body via a fixed bracket and rotates with the vehicle body relative to the first vehicle body when the tiller turns; the input shaft of the angle sensor and the optical shaft structure are coaxially connected via a flexible coupling.

9. An electric folding tiller according to claim 7, characterized in that, The main control unit has a built-in zero-point self-calibration module, which is used by the integrated navigation and positioning terminal to determine that the tiller is traveling in a straight line and that its lateral deviation d and heading deviation are within the correct range. When the value remains within the preset threshold, the system automatically reads the current physical output value of the angle sensor and updates it to the absolute zero reference value at the system software level.

10. An electric folding tiller according to claim 7, characterized in that, The steering actuator includes a steering motor and a worm gear steering mechanism; The main control unit is based on the target bending angle. With real-time actual bending angle The angle error e generates a PWM drive signal, which controls the steering motor to move, and then pushes the first car body and the second car body to fold relative to each other through the worm gear steering mechanism.

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