AGV double-vehicle linkage adaptive motion control method and system

Abstract

The application discloses an AGV double-vehicle linkage adaptive motion control method and system, and belongs to the technical field of industrial automatic logistics equipment. The method integrates the double vehicles into a unified rigid whole by constructing an eight-steering-wheel virtual rigid body motion model; communication delay compensation is realized by using a dynamic clipping and interpolation algorithm based on a time queue; and a sliding mode control algorithm fusing a quadratic term of a distance error and an error change rate is used to quickly converge a cooperative error. The application effectively solves the technical problems of poor trajectory consistency and large synchronization error caused by model fragmentation, communication delay and external disturbance in the cooperative motion of heavy-load AGVs, and significantly improves the cooperative motion precision and anti-interference ability of heavy-load logistics equipment.

Description

Technical Field

[0001] This invention relates to the field of intelligent industrial logistics technology, and in particular to an AGV dual-vehicle linkage adaptive motion control method and system. Background Technology

[0002] Automated Guided Vehicles (AGVs) are core equipment in modern industrial automated logistics systems, widely used in material handling, assembly line delivery, and flexible manufacturing systems. In the assembly of heavy equipment (such as buses and aircraft parts), due to the oversized and overweight characteristics of the materials, the carrying capacity and size of a single AGV cannot meet the requirements, making multi-AGV collaborative operation technology a key solution to this problem.

[0003] Currently, master-slave tracking control is the mainstream solution for dual AGV linkage. In this solution, the master vehicle moves independently according to a preset trajectory and transmits its position and speed information to the slave vehicle via wireless communication. The slave vehicle then performs tracking control based on the received information. However, this existing technology has significant drawbacks: First, it treats the master and slave vehicles as two independent motion units, lacking a unified cooperative kinematic model, resulting in poor trajectory consistency when the two vehicles turn or change tracks, easily leading to motion interference and tail-wagging phenomena. Second, the system communication delay is not effectively compensated, causing the slave vehicle's control commands to lag, introducing synchronization errors. Third, traditional control algorithms (such as PID) have poor robustness to ground disturbances and load changes, insufficient dynamic adjustment capabilities, and slow error convergence. Finally, existing systems lack the ability to dynamically adjust the distance between the two vehicles online, making it difficult to flexibly adapt to the handling needs of materials of different specifications, resulting in low flexibility.

[0004] Therefore, existing technologies are insufficient to meet the stringent requirements for the coordinated motion control of dual AGVs in heavy-duty and high-precision applications. There is an urgent need for a new control method that can integrate dual-vehicle models, compensate for communication delays, possess strong anti-interference capabilities, and support dynamic spacing adjustment. Summary of the Invention

[0005] The technical problem to be solved by this invention is the poor trajectory consistency, large synchronization error and weak anti-interference ability caused by model fragmentation, communication delay and external disturbance in the existing heavy-duty AGV dual-vehicle linkage system.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an AGV dual-vehicle linkage adaptive motion control method, comprising the following steps:

[0007] Construct an eight-steering-wheel virtual rigid body motion model, and map the eight steering wheels of the master vehicle and slave vehicle to a rigid overall model centered on the midpoint of the connection between the two vehicles;

[0008] The main vehicle generates the overall motion command of the virtual rigid body model according to the preset motion trajectory, and calculates the target motion state of each steering wheel based on the model;

[0009] The master vehicle sends the overall motion command with a timestamp to the slave vehicle;

[0010] The vehicle receives the timestamped overall motion command and performs dynamic trimming and interpolation compensation on the command based on the calculated communication delay to generate a target speed command synchronized with the main vehicle's motion state.

[0011] The vehicle independently calculates the steering control amount of its steering wheel based on the synchronized target speed command and the overall position and posture deviation;

[0012] Based on the actual distance error between the two vehicles and its rate of change, a secondary dynamic sliding mode control algorithm is used to generate the speed compensation amount of the slave vehicle.

[0013] The compensated final speed command and steering control quantity are sent to the actuators of each steering wheel of the slave vehicle to drive the movement of the slave vehicle, so as to achieve coordinated linkage with the master vehicle.

[0014] Furthermore, the step of the master vehicle sending the timestamped overall motion command to the slave vehicle includes:

[0015] The main vehicle controller generates and stores a queue of target speed arrays for a future period of time at fixed intervals, with each array element having a precise timestamp;

[0016] The target speed array queue is sent to the slave vehicle via wireless communication.

[0017] Furthermore, the step of receiving the timestamped overall motion command from the vehicle and dynamically pruning and interpolating the command based on the calculated communication delay to generate a target speed command synchronized with the motion state of the master vehicle includes:

[0018] The vehicle calculates the total communication delay time based on the time it receives the data.

[0019] The received speed array queue is dynamically pruned based on the total communication delay time, and outdated instruction elements are deleted.

[0020] Linear interpolation is performed on the first element of the pruned queue to calculate the target speed command that precisely matches the current time.

[0021] Furthermore, the step of the vehicle independently calculating the steering control amount of its steering wheel based on the synchronized target speed command and the overall posture deviation includes:

[0022] The steering control quantity is obtained by mapping the deviation function between the overall pose of the virtual rigid body model and the actual pose of the slave vehicle; the steering control quantity includes the steering angle of each steering wheel of the slave vehicle, and the calculation of the steering angle ensures that the steering of the slave vehicle is consistent with the motion trajectory of the master vehicle.

[0023] Furthermore, the step of generating the slave vehicle speed compensation amount using a quadratic dynamic sliding mode control algorithm based on the actual distance error between the two vehicles and its rate of change includes:

[0024] Construct a sliding surface that integrates the spacing error and the quadratic term of the error change rate;

[0025] Based on the sliding surface and its changing trend, the vehicle speed compensation amount is dynamically calculated and output.

[0026] Furthermore, in the step of constructing the sliding surface for the fusion spacing error and the quadratic term of the error change rate, the functional expression of the sliding surface includes the error change rate, the first term of the error, and the quadratic term; the coefficients of the first term and the quadratic term are determined through system stability analysis to ensure that the sliding surface has dynamic convergence characteristics.

[0027] Furthermore, the AGV dual-vehicle linkage adaptive motion control method also includes a dynamic adjustment step for the distance between the two vehicles, specifically:

[0028] Determine the target distance between the two vehicles based on the length of the target material being transported;

[0029] The current distance is gradually adjusted to the target distance using a preset maximum step size to avoid impact during movement.

[0030] Furthermore, the AGV dual-vehicle linkage adaptive motion control method also includes a pose feedback optimization step, specifically:

[0031] By integrating data from the vehicle's odometer and visual sensors, the vehicle's true position and orientation can be estimated in real time.

[0032] The estimated true pose of the main vehicle is fed back into the trajectory tracking closed loop to optimize the overall motion command.

[0033] Furthermore, the AGV dual-vehicle linkage adaptive motion control method also includes a safety monitoring step, specifically:

[0034] Real-time interaction of safety interlock signals between master and slave vehicles;

[0035] Based on the level of the received safety signal, the corresponding control mode switching, including deceleration, stopping, or emergency stop, is triggered.

[0036] The present invention also provides an AGV dual-vehicle linkage adaptive motion control system, comprising:

[0037] The virtual rigid body modeling module is used to construct an eight-steering wheel virtual rigid body motion model, which maps the eight steering wheels of the main vehicle and the slave vehicle to a rigid overall model centered on the midpoint of the connection between the two vehicles.

[0038] The main vehicle control module is used to generate the overall motion command of the virtual rigid body model according to the preset motion trajectory, and to calculate the target motion state of each steering wheel based on the model.

[0039] A wireless communication module is used for the master vehicle to send the overall motion command with timestamps to the slave vehicle;

[0040] The delay compensation module is used to receive the timestamped overall motion command from the vehicle, and dynamically trim and interpolate the command based on the calculated communication delay to generate a target speed command that is synchronized with the motion state of the main vehicle.

[0041] The steering calculation module is used to independently calculate the steering control amount of the steering wheel of the vehicle based on the synchronized target speed command and the overall posture deviation.

[0042] The sliding mode compensation control module is used to generate the slave vehicle speed compensation amount based on the actual distance error between the two vehicles and its rate of change, using a secondary dynamic sliding mode control algorithm.

[0043] The steering wheel actuator module is used to send the compensated final speed command and steering control quantity to each steering wheel actuator of the slave vehicle to drive the slave vehicle to move, so as to achieve coordinated linkage with the master vehicle.

[0044] The beneficial effects of this invention are as follows: By constructing an eight-steering wheel virtual rigid body motion model, this invention integrates the master and slave vehicles into a unified rigid whole for collaborative control, fundamentally solving the trajectory consistency problem caused by the traditional fragmented model; through a time queue-based dynamic pruning and interpolation algorithm, it effectively compensates for communication delays and achieves precise synchronization of speed commands between the master and slave vehicles in the time dimension; furthermore, through a secondary dynamic sliding mode compensation algorithm, it quickly suppresses spacing errors and external disturbances; and significantly improves the system's synchronization, stability, and anti-interference capabilities in complex industrial environments. Attached Figure Description

[0045] Figure 1 This is a flowchart of the AGV dual-vehicle linkage adaptive motion control method according to an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the virtual rigid body motion model of the eight steering wheels according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of dual-vehicle communication according to an embodiment of the present invention;

[0048] Figure 4This is a block diagram of the AGV dual-vehicle linkage adaptive motion control device according to an embodiment of the present invention. Detailed Implementation

[0049] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that the descriptions involving "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0051] Please see Figure 1 The first embodiment of the present invention is: an AGV dual-vehicle linkage adaptive motion control method, comprising the following steps:

[0052] S10. Construct an eight-steering wheel virtual rigid body motion model, and map the eight steering wheels of the main vehicle and the slave vehicle to a rigid overall model centered on the midpoint of the connection between the two vehicles.

[0053] In this embodiment, as Figure 2 As shown, a precise mechanical model of the four steering wheels of the vehicle is established. Taking the vehicle's own center of motion as the origin, the precise position coordinates of the rotational center of each steering wheel in the two-dimensional plane are determined. Simultaneously, the length and width extension dimensions of the vehicle are defined, providing accurate basic data for the subsequent construction of the overall model.

[0054] Establish a two-dimensional rectangular coordinate system with the vehicle's own center of motion as the origin O′. The steering wheel position parameters are as follows: the coordinates of the rotation centers of the four steering wheels (numbered 1-4) are:

[0055] Steering wheel 1: (x1, y1) = (+1.072m, -0.385m);

[0056] Steering wheel 2: (x2, y2) = (-1.072m, +0.385m);

[0057] Steering wheel 3: (x3, y3) = (+1.136m, +0.453m);

[0058] Steering wheel 4: (x4, y4) = (-1.136m, -0.453m);

[0059] Vehicle dimensions: 3m long, 2m wide.

[0060] Based on the single-vehicle four-steering-wheel mechanical model, and combined with the actual distance between the front and rear vehicles, an eight-steering-wheel virtual rigid body motion model is constructed. The master and slave vehicles are regarded as a rigid whole centered on the connecting midpoint O. Based on relevant kinematic and dynamic principles, the possible error states of this rigid body model during motion are precisely defined, providing accurate error analysis basis for subsequent control strategies.

[0061] O is the virtual rigid body center, with the coordinate origin (0,0,0) as the midpoint of the connection between the two vehicles, and is the kinematic reference center of the entire virtual rigid body model;

[0062] O1 is the center point of motion of the main vehicle (front vehicle). Located to the right of the X-axis, the distance from O is L / 2 (L is the distance between the center points of the master and slave vehicles).

[0063] O2 is the center point of motion of the vehicle (rear vehicle) itself. Located to the left of the X-axis, at a distance of L / 2 from O, and symmetrical to O1 about O;

[0064] θ is the overall heading angle of the virtual rigid body (the angle between it and the X-axis of the two-dimensional coordinate system), which is the unified heading angle when the master and slave vehicles move together.

[0065] L is the distance between the center points of the master and slave vehicles (initial value 4m, dynamically adjustable range 4-6m).

[0066] (x' 1i ,y' 1i ) is the coordinate of the i-th steering wheel (i=1,2,3,4) of the main vehicle relative to its own center point O1;

[0067] (x 1i = x' 1i + L / 2 ,y 1i = y' 1i ) is the coordinate of the i-th steering wheel (i=1,2,3,4) of the main vehicle relative to the origin O;

[0068] (x' 2j ,y' 2j Let be the coordinates of the j-th steering wheel (j=1,2,3,4) of the vehicle relative to its center point O2;

[0069] (x 2j = x' 2j- L / 2 ,y 1i = y' 2j Let be the coordinates of the j-th steering wheel (j=1,2,3,4) of the vehicle relative to the origin O;

[0070] Mathematical formulas for kinematic commands and the position angles of the eight steering wheels:

[0071] The kinematic commands for a virtual rigid body are the overall motion parameters: linear velocity (v) x ,v y (along the X and Y axes), angular velocity ω (rotating around point O). According to the principles of rigid body kinematics, the linear velocity and steering angle of each steering wheel must satisfy the overall motion state.

[0072] S20. The main vehicle generates the overall motion command of the virtual rigid body model according to the preset motion trajectory, and calculates the target motion state of each steering wheel based on the model.

[0073] In this embodiment, the linear velocity of the steering wheel is calculated as follows: for any steering wheel The coordinates relative to O are (x k ,y k Its linear velocity vector expression is: ;

[0074] Derivation: The velocity of any point on a rigid body = the translational velocity of the rigid body + the linear velocity generated by the rotation of the rigid body (angular velocity × cross product of the position vector from the point to the center of rotation).

[0075] The magnitude of the steering wheel's linear velocity is: ;

[0076] Calculation of steering wheel angle: Steering wheel angle α k The angle between the X-axis and the x-axis must be consistent with the direction of the linear velocity itself, that is: ;

[0077] Error state definition (based on virtual rigid body center O): Using O as a reference, the error state of the coordinated motion of the two vehicles is defined to provide a basis for subsequent compensation control.

[0078] ΔP t Synchronization error of the virtual rigid body model: ΔP t =ΔP1-ΔP2;

[0079] ΔP1 is the deviation of the main vehicle from the ideal position of the virtual rigid body model. ΔP1 = O1 - O1', where O1 is the actual position of the main vehicle and O1' is the ideal position of the main vehicle.

[0080] ΔP2 represents the deviation of the vehicle from its ideal position relative to the virtual rigid body model. ΔP2 = O2 - O2', where O2 is the actual position of the vehicle and O2' is its ideal position.

[0081] S30, The master vehicle sends the overall motion command with a timestamp to the slave vehicle;

[0082] Furthermore, the step of the master vehicle sending the timestamped overall motion command to the slave vehicle includes:

[0083] The main vehicle controller generates and stores a queue of target speed arrays for a future period of time at fixed intervals, with each array element having a precise timestamp;

[0084] The target speed array queue is sent to the slave vehicle via wireless communication.

[0085] In this embodiment, the eight-steering-wheel model is specifically applied to a master-slave dual-vehicle system. The front vehicle acts as the master vehicle, and the rear vehicle acts as the slave vehicle. In the master vehicle's motion model, its own four steering wheels serve as the first four physical wheels, providing real-time feedback on travel and steering data. Simultaneously, the rear vehicle's four steering wheels are incorporated into the model as the last four virtual wheels, providing corresponding travel and steering data. The master vehicle's motion control is entirely independent, autonomously deciding its motion state based on preset trajectory planning and environmental perception information.

[0086] In the rear vehicle motion model, the rear vehicle's own four steering wheels serve as the four rear physical wheels, providing feedback on movement and steering data. The front vehicle's four steering wheels serve as the four front virtual wheels, providing reference data for the rear vehicle model. The rear vehicle's wheel speed is uniformly controlled by the main vehicle to ensure speed coordination with the main vehicle; while the rear vehicle's steering is independently calculated and controlled based on overall pose information, thereby ensuring that the rear vehicle can accurately follow the main vehicle's trajectory and achieve coordinated movement between the two vehicles.

[0087] Physical wheel (main vehicle 4 steering wheels) feedback data: speed v 1i Steering angle ;

[0088] Virtual wheel (from the 4th steering wheel of the vehicle) reference data: speed v 2i Steering angle .

[0089] Independent speed control command for main vehicle: V m =[v x ,v y ,ω](v x Longitudinal velocity, v y Lateral velocity, ω (angular velocity).

[0090] Physical wheel (from the car's 4th steering wheel) feedback data: speed v 2i Steering angle ;

[0091] Virtual wheel (main vehicle 4 steering wheels) reference data: speed v 1i Steering angle .

[0092] Calculated from the vehicle's steering angle (based on overall pose): (f is a steering angle mapping function based on virtual rigid body pose deviation to ensure trajectory following).

[0093] like Figure 3 As shown, pairing and communication are achieved through Bluetooth communication devices installed on both the master and slave vehicles. During communication, the transmitted data follows clear classification and format specifications. Communication data sent from the master vehicle to the slave vehicle includes, but is not limited to, steering wheel speed commands, precise master vehicle position and orientation information, master vehicle safety interlock signals, real-time master vehicle steering wheel feedback data, precise communication timestamps, and the master vehicle's current control mode. Communication data sent from the slave vehicle to the master vehicle includes slave vehicle position and orientation information, slave vehicle safety interlock signals, slave vehicle steering wheel feedback data, communication timestamps, and the slave vehicle's control mode. Accurate exchange of this data provides crucial information support for the coordinated control of the two vehicles.

[0094] The main vehicle transmits data: timestamp (t); speed array V m =[v x ,v y [,ω]; Pose (x1,y1,θ1); Safety interlock signals (slow,stop,estop); Steering wheel feedback [v 1i ,α 1i ]; Control mode.

[0095] Data transmitted from the vehicle: pose Safety interlock signal (same as above); steering wheel feedback [v] 2j ,α 2j ]; Control mode feedback (mode).

[0096] S40. Receive the timestamped overall motion command from the vehicle, and dynamically trim and interpolate the command based on the calculated communication delay to generate a target speed command synchronized with the motion state of the main vehicle.

[0097] Furthermore, the step of receiving the timestamped overall motion command from the vehicle and dynamically pruning and interpolating the command based on the calculated communication delay to generate a target speed command synchronized with the motion state of the master vehicle includes:

[0098] The vehicle calculates the total communication delay time based on the time it receives the data.

[0099] The received speed array queue is dynamically pruned based on the total communication delay time, and outdated instruction elements are deleted.

[0100] Linear interpolation is performed on the first element of the pruned queue to calculate the target speed command that precisely matches the current time.

[0101] In this embodiment, based on the slave vehicle target speed synchronization and communication delay compensation using a time queue, the master vehicle controller calculates the delay τ relative to the current time t. fixd The target velocity V within a given time period pre The release interval is T, arranged in chronological order according to time t. pub Target velocity array queue V pre (t) i ) = [v x , v y , ω], where v x and v y Let ω and t represent the velocity components in the two-dimensional plane, respectively, where ω represents the angular velocity and t represents the timestamp. The number of elements in the target velocity array of the main vehicle is N = τ. fixd / T pub The first element V pre (t0) represents the target speed published in the current control cycle. After the speed is published, the next element will be shifted forward by V. pre (t) i )= V pre (t) i+1 ).

[0102] Simultaneously, the main vehicle sends a target speed array V with precise timestamps. pre (t) i The data is given to the slave vehicle, which, upon receiving the speed array, determines the speed based on the current time t. now Calculate the total communication delay τ com (τ) com =τ proc +τ fluc Total communication delay includes fixed data processing delay τ proc (Measurable), dynamic communication fluctuation delay τ fluc (From the time the slave requests data to the time it receives the returned data), the target speed V will be... pre (t) i ) before [τ com / T pub After deleting one element, the remaining elements are shifted forward, and the compensation speed is calculated using linear interpolation.

[0103] (t) i ≤t sync ≤t i+1 );

[0104] V comp To compensate for speed, V i Let V be the velocity at time i. i+1 Let t be the velocity at time i+1. i Let t be the time at the i-th moment. i+1 Let t be the time at time i+1. sync To synchronize time.

[0105] The result V comp Synchronize to the target speed release array queue V from the vehicle pre (t) j By updating the speed through rolling interpolation, the synchronization error caused by the communication delay between the master and slave vehicles is accurately compensated, ensuring that the slave vehicle can respond to the speed command of the master vehicle in a timely and accurate manner, thereby improving the synchronization and accuracy of the movement of the two vehicles.

[0106] S50. The vehicle independently calculates the steering control amount of its steering wheel based on the synchronized target speed command and the overall position and posture deviation.

[0107] Furthermore, the step of the vehicle independently calculating the steering control amount of its steering wheel based on the synchronized target speed command and the overall posture deviation includes:

[0108] The steering control quantity is obtained by mapping the deviation function between the overall pose of the virtual rigid body model and the actual pose of the slave vehicle; the steering control quantity includes the steering angle of each steering wheel of the slave vehicle, and the calculation of the steering angle ensures that the steering of the slave vehicle is consistent with the motion trajectory of the master vehicle.

[0109] In this embodiment, a closed-loop system for estimating the true pose of the main vehicle and constructing a state backtracking loop is performed. This system comprehensively utilizes the main vehicle pose information, mileage feedback data, and detection results from the depth camera, employing an advanced multi-sensor fusion algorithm to accurately estimate the main vehicle's true pose. By weighted fusion and error correction of data from different sensors, the accuracy and reliability of the main vehicle pose estimation are improved. Based on this, a state backtracking closed-loop system is constructed to feed the estimated true pose information of the main vehicle back into the control strategy, enabling real-time adjustment and optimization of the main vehicle's motion state and ensuring that the main vehicle can move precisely along a preset trajectory.

[0110] Tracking error (P) pre (for predicting trajectory pose).

[0111] Adjusting the vehicle speed via feedback control: (Kp is the proportionality coefficient, which ensures error convergence).

[0112] S60. Based on the actual distance error between the two vehicles and its rate of change, a secondary dynamic sliding mode control algorithm is used to generate the speed compensation amount of the slave vehicle.

[0113] Furthermore, the step of generating the slave vehicle speed compensation amount using a quadratic dynamic sliding mode control algorithm based on the actual distance error between the two vehicles and its rate of change includes:

[0114] Construct a sliding surface that integrates the spacing error and the quadratic term of the error change rate;

[0115] Based on the sliding surface and its changing trend, the vehicle speed compensation amount is dynamically calculated and output.

[0116] Furthermore, in the step of constructing the sliding surface for the fusion spacing error and the quadratic term of the error change rate, the functional expression of the sliding surface includes the error change rate, the first term of the error, and the quadratic term; the coefficients of the first term and the quadratic term are determined through system stability analysis to ensure that the sliding surface has dynamic convergence characteristics.

[0117] S70 sends the compensated final speed command and steering control quantity to the actuators of each steering wheel of the slave vehicle to drive the slave vehicle to move, so as to achieve coordinated linkage with the master vehicle.

[0118] In this embodiment, the distance L between the front and rear vehicles is estimated based on the actual pose of the main vehicle. act The ideal distance L set by the virtual rigid body motion model of the eight steering wheels set Compare the two and calculate the error e (spacing error, e = L) between them. act -L set A quadratic dynamic sliding mode compensation algorithm is used to adjust control parameters in real time based on the magnitude and trend of the error, generating the final wheel speed array. This wheel speed array is applied to the physical wheel actuators of the slave vehicle. Through precise speed control and steering adjustment, the slave vehicle can quickly and accurately eliminate the error between itself and the master vehicle, ensuring the synchronization accuracy and cooperative performance of the two vehicles.

[0119] e' is the rate of change of error. (This reflects the trend of error over time; ideally, e'=0).

[0120] s is a quadratic dynamic sliding surface. The quadratic terms of the fusion error and the rate of change of error are defined as:

[0121] s = e' + λ1e + λ2e 2 ;

[0122] Wherein, λ1>0 and λ2>0 are sliding surface parameters (determined through system stability analysis, such as λ1=5 and λ2=2), to ensure that the sliding surface has dynamic convergence characteristics;

[0123] u0 is the basic control variable, and the compensation speed V is based on calculation. comp Transformed vehicle speed command (including v) x0 ,v y0 ,ω0);

[0124] u is the final control quantity from the vehicle, u = u0 + Δu, where Δu is the sliding mode compensation quantity;

[0125] k is the sliding mode gain, which is set according to the maximum disturbance limit of the system.

[0126] Furthermore, in one specific embodiment, the AGV dual-vehicle linkage adaptive motion control method further includes a dynamic adjustment step for the distance between the two vehicles, specifically:

[0127] Determine the target distance between the two vehicles based on the length of the target material being transported;

[0128] The current distance is gradually adjusted to the target distance using a preset maximum step size to avoid impact during movement.

[0129] In this embodiment, when the two vehicles need to accommodate materials of different lengths, the spacing between the first four steering wheels and the last four steering wheels in the eight-steering-wheel virtual rigid body motion model is dynamically adjusted in stages. The adjustment process follows a specific control strategy and algorithm to ensure its smoothness and accuracy, avoiding system instability or material damage caused by excessively rapid or large spacing adjustments. This dynamic adjustment mechanism allows the dual-vehicle system to flexibly adapt to the handling needs of materials of different specifications, improving the system's versatility and applicability.

[0130] Target spacing L target (e.g., a 12.9-meter electric bus corresponds to 6 meters), initial spacing L init Maximum adjustment step size in a single operation .

[0131] Number of adjustments and step size: Total adjustment amount Number of adjustments:

[0132] ( (This is a rounding function to ensure smooth adjustments at each step and avoid shocks).

[0133] Furthermore, in one specific embodiment, the AGV dual-vehicle linkage adaptive motion control method further includes a pose feedback optimization step, specifically:

[0134] By integrating data from the vehicle's odometer and visual sensors, the vehicle's true position and orientation can be estimated in real time.

[0135] Real-time interaction of safety interlock signals between master and slave vehicles;

[0136] Based on the level of the received safety signal, the corresponding control mode switching, including deceleration, stopping, or emergency stop, is triggered.

[0137] In summary, the laser-guided AGV dual-vehicle linkage adaptive motion control scheme proposed in this invention achieves a technological breakthrough in the field of heavy-duty AGV collaborative motion control through three core technological innovations, yielding significant technical results. First, by constructing an eight-steering-wheel virtual rigid body motion model, the kinematic parameters of the eight steering wheels of the master and slave vehicles are unified and integrated into a rigid overall model centered on the connection midpoint. This fundamentally solves the problem of poor trajectory consistency caused by the fragmentation of traditional dual-vehicle models, laying a model foundation for high-precision collaborative control. Second, the innovative time-queue-based synchronization and communication delay compensation algorithm, through dynamic pruning and linear interpolation optimization, achieves precise quantitative compensation for communication delays, ensuring a high degree of matching between the slave vehicle's speed command and the master vehicle's motion state in the time dimension, effectively eliminating synchronization errors caused by communication lag. Finally, for dual-vehicle collaborative errors and external disturbances, a quadratic dynamic sliding mode compensation algorithm is adopted. By constructing a sliding mode surface that fuses the spacing error and the quadratic term of the error change rate, rapid convergence and suppression of collaborative errors are achieved, significantly improving the system's anti-interference capability and robustness. Ultimately, the technical solution was successfully applied in the assembly and transfer scenario of 15-ton, 10-12.9-meter electric buses, achieving high-precision control indicators of dual-vehicle synchronous position error ≤ ±15mm and angle error ≤ 0.5°. It effectively solved the industry pain points of low collaborative precision and insufficient flexibility of traditional heavy-duty AGVs, promoted the upgrading of heavy-duty logistics equipment towards high precision and intelligence, and has important engineering application value and promotion prospects.

[0138] like Figure 4 As shown in the figure, this embodiment of the invention also provides an AGV dual-vehicle linkage adaptive motion control system, including:

[0139] The virtual rigid body modeling module 10 is used to construct an eight-steering wheel virtual rigid body motion model, which maps the eight steering wheels of the main vehicle and the slave vehicle to a rigid overall model centered on the midpoint of the connection between the two vehicles.

[0140] The main vehicle control module 20 is used to generate the overall motion command of the virtual rigid body model according to the preset motion trajectory, and to calculate the target motion state of each steering wheel based on the model.

[0141] The wireless communication module 30 is used for the master vehicle to send the overall motion command with a timestamp to the slave vehicle;

[0142] The delay compensation module 40 is used to receive the timestamped overall motion command from the vehicle, and dynamically trim and interpolate the command based on the calculated communication delay to generate a target speed command that is synchronized with the motion state of the main vehicle.

[0143] The steering calculation module 50 is used to independently calculate the steering control amount of the steering wheel of the vehicle based on the synchronized target speed command and the overall posture deviation.

[0144] The sliding mode compensation control module 60 is used to generate the slave vehicle speed compensation amount based on the actual distance error between the two vehicles and its rate of change using a secondary dynamic sliding mode control algorithm.

[0145] The steering wheel actuator module 70 is used to send the compensated final speed command and steering control quantity to each steering wheel actuator of the slave vehicle to drive the slave vehicle to move, so as to achieve coordinated linkage with the master vehicle.

[0146] Furthermore, the wireless communication module 30 is specifically used for:

[0147] The main vehicle controller generates and stores a queue of target speed arrays for a future period of time at fixed intervals, with each array element having a precise timestamp;

[0148] Furthermore, the delay compensation module 40 is specifically used for:

[0149] The vehicle calculates the total communication delay time based on the time it receives the data.

[0150] The received speed array queue is dynamically pruned based on the total communication delay time, and outdated instruction elements are deleted.

[0151] Linear interpolation is performed on the first element of the pruned queue to calculate the target speed command that precisely matches the current time.

[0152] Furthermore, the turn-to-computation module 50 is specifically used for:

[0153] The steering control quantity is obtained by mapping the deviation function between the overall pose of the virtual rigid body model and the actual pose of the slave vehicle; the steering control quantity includes the steering angle of each steering wheel of the slave vehicle, and the calculation of the steering angle ensures that the steering of the slave vehicle is consistent with the motion trajectory of the master vehicle.

[0154] Furthermore, the sliding mode compensation control module 60 is specifically used for:

[0155] Construct a sliding surface that integrates the spacing error and the quadratic term of the error change rate;

[0156] Based on the sliding surface and its changing trend, the vehicle speed compensation amount is dynamically calculated and output.

[0157] Furthermore, in the step of constructing the sliding surface for the fusion spacing error and the quadratic term of the error change rate, the functional expression of the sliding surface includes the error change rate, the first term of the error, and the quadratic term; the coefficients of the first term and the quadratic term are determined through system stability analysis to ensure that the sliding surface has dynamic convergence characteristics.

[0158] Furthermore, the AGV dual-vehicle linkage adaptive motion control system also includes a dual-vehicle spacing dynamic adjustment module, specifically used for:

[0159] Determine the target distance between the two vehicles based on the length of the target material being transported;

[0160] The current distance is gradually adjusted to the target distance using a preset maximum step size to avoid impact during movement.

[0161] Furthermore, the AGV dual-vehicle linkage adaptive motion control system also includes a pose feedback optimization module, specifically used for:

[0162] By integrating data from the vehicle's odometer and visual sensors, the vehicle's true position and orientation can be estimated in real time.

[0163] The estimated true pose of the main vehicle is fed back into the trajectory tracking closed loop to optimize the overall motion command.

[0164] Furthermore, the AGV dual-vehicle linkage adaptive motion control system also includes a safety monitoring module, specifically used for:

[0165] Real-time interaction of safety interlock signals between master and slave vehicles;

[0166] Based on the level of the received safety signal, the corresponding control mode switching, including deceleration, stopping, or emergency stop, is triggered.

[0167] It should be noted that those skilled in the art can clearly understand that the specific implementation process of the above-mentioned AGV dual-vehicle linkage adaptive motion control system can be referred to the corresponding description in the foregoing method embodiments. For the sake of convenience and brevity, it will not be repeated here.

[0168] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A dual-vehicle linkage adaptive motion control method for AGVs, characterized in that, Includes the following steps: Construct an eight-steering-wheel virtual rigid body motion model, and map the eight steering wheels of the master vehicle and slave vehicle to a rigid overall model centered on the midpoint of the connection between the two vehicles; The main vehicle generates the overall motion command of the virtual rigid body motion model according to the preset motion trajectory, and calculates the target motion state of each steering wheel based on the model; The master vehicle sends the overall motion command with a timestamp to the slave vehicle; The vehicle receives the timestamped overall motion command and performs dynamic trimming and interpolation compensation on the command based on the calculated communication delay to generate a target speed command synchronized with the main vehicle's motion state. The vehicle independently calculates the steering control amount of its steering wheel based on the synchronized target speed command and the overall position and posture deviation; Based on the actual distance error between the two vehicles and its rate of change, a secondary dynamic sliding mode control algorithm is used to generate the speed compensation amount of the slave vehicle. The compensated final speed command and steering control quantity are sent to the actuators of each steering wheel of the slave vehicle to drive the movement of the slave vehicle, so as to achieve coordinated linkage with the master vehicle; The step of generating the slave vehicle speed compensation amount using a quadratic dynamic sliding mode control algorithm based on the actual distance error between the two vehicles and its rate of change includes: Construct a sliding surface that integrates the spacing error and the quadratic term of the error change rate; Based on the sliding surface and its changing trend, the vehicle speed compensation amount is dynamically calculated and output.

2. The AGV dual-vehicle linkage adaptive motion control method according to claim 1, characterized in that, The step of the master vehicle sending the timestamped overall motion command to the slave vehicle includes: The main vehicle controller generates and stores a queue of target speed arrays for a future period of time at fixed intervals, with each array element having a precise timestamp; The target speed array queue is sent to the slave vehicle via wireless communication.

3. The AGV dual-vehicle linkage adaptive motion control method according to claim 1, characterized in that, The steps of receiving the timestamped overall motion command from the vehicle and dynamically pruning and interpolating the command based on the calculated communication delay to generate a target speed command synchronized with the motion state of the master vehicle include: The vehicle calculates the total communication delay time based on the time it receives the data. The received speed array queue is dynamically pruned based on the total communication delay time, and outdated instruction elements are deleted. Linear interpolation is performed on the first element of the pruned queue to calculate the target speed command that precisely matches the current time.

4. The AGV dual-vehicle linkage adaptive motion control method according to claim 1, characterized in that, The step of the slave vehicle independently calculating the steering control amount of its steering wheel based on the synchronized target speed command and the overall positional deviation includes: The steering control quantity is obtained by mapping the deviation function between the overall pose of the virtual rigid body motion model and the actual pose of the slave vehicle; the steering control quantity includes the steering angle of each steering wheel of the slave vehicle, and the calculation of the steering angle ensures that the steering of the slave vehicle is consistent with the motion trajectory of the master vehicle.

5. The AGV dual-vehicle linkage adaptive motion control method according to claim 1, characterized in that, In the step of constructing the sliding surface for the fusion spacing error and the quadratic term of the error change rate, the functional expression of the sliding surface includes the error change rate, the first term of the error, and the quadratic term; the coefficients of the first term and the quadratic term are determined through system stability analysis to ensure that the sliding surface has dynamic convergence characteristics.

6. The AGV dual-vehicle linkage adaptive motion control method according to claim 1, characterized in that, It also includes a dynamic adjustment step for the distance between the two vehicles, specifically: Determine the target distance between the two vehicles based on the length of the target material being transported; The current distance is gradually adjusted to the target distance using a preset maximum step size to avoid impact during movement.

7. The AGV dual-vehicle linkage adaptive motion control method according to claim 1, characterized in that, It also includes pose feedback optimization steps, specifically: By integrating data from the vehicle's odometer and visual sensors, the vehicle's true position and orientation can be estimated in real time. The estimated true pose of the main vehicle is fed back into the trajectory tracking closed loop to optimize the overall motion command.

8. The AGV dual-vehicle linkage adaptive motion control method according to claim 1, characterized in that, It also includes security monitoring steps, specifically: Real-time interaction of safety interlock signals between master and slave vehicles; Based on the level of the received safety signal, the corresponding control mode switching, including deceleration, stopping, or emergency stop, is triggered.

9. An AGV dual-vehicle linkage adaptive motion control system, characterized in that, include: The virtual rigid body modeling module is used to construct an eight-steering wheel virtual rigid body motion model, which maps the eight steering wheels of the main vehicle and the slave vehicle to a rigid overall model centered on the midpoint of the connection between the two vehicles. The main vehicle control module is used to generate the overall motion command of the virtual rigid body motion model according to the preset motion trajectory, and to calculate the target motion state of each steering wheel based on the model. A wireless communication module is used for the master vehicle to send the overall motion command with timestamps to the slave vehicle; The delay compensation module is used to receive the timestamped overall motion command from the vehicle, and dynamically trim and interpolate the command based on the calculated communication delay to generate a target speed command that is synchronized with the motion state of the main vehicle. The steering calculation module is used to independently calculate the steering control amount of the steering wheel of the vehicle based on the synchronized target speed command and the overall posture deviation. The sliding mode compensation control module is used to generate the slave vehicle speed compensation amount based on the actual distance error between the two vehicles and its rate of change, using a secondary dynamic sliding mode control algorithm. The steering wheel actuator module is used to send the compensated final speed command and steering control quantity to each steering wheel actuator of the slave vehicle to drive the slave vehicle to move, so as to achieve coordinated linkage with the master vehicle; The sliding mode compensation control module is specifically used for: Construct a sliding surface that integrates the spacing error and the quadratic term of the error change rate; Based on the sliding surface and its changing trend, the vehicle speed compensation amount is dynamically calculated and output.

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