A port container tyre crane walking drive control method

Abstract

The present application belongs to the technical field of port machinery automation control, and relates to a port container rubber-tired crane walking driving control method. The present application calculates the steering compensation and the differential compensation corresponding to the lateral deviation and the heading angle deviation of the rubber-tired crane in real time through the state space grid mapping technology, evaluates the health state grade of each tire based on the tire tread depth and the cumulative running time, and constructs a differentiated allocation strategy. Under the physical execution constraint condition, the compensation is allocated according to the principle that the high health state tire bears the leading allocation, the medium health state tire bears the basic allocation, and the low health state tire bears the auxiliary allocation or does not bear the allocation, and the double safety protection is carried out in combination with the environment safety monitoring and the tire physical constraint checking mechanism. The method effectively solves the problems of low control accuracy, unbalanced tire wear and safety hidden trouble caused by uneven tire state in the walking process of the traditional rubber-tired crane, and improves the automatic guiding accuracy and stability of the rubber-tired crane.

Description

Technical Field

[0001] This invention belongs to the field of port machinery automation control technology, and relates to a method for driving the travel of a port container tire crane. Background Technology

[0002] Rubber-tired gantry cranes (LTGs) are crucial equipment in container yards for loading, unloading, and handling containers. However, due to their large size and unique movement mechanism, they are prone to deviation and have blind spots during movement. Therefore, their ability to correct deviation and their collision avoidance capabilities directly determine the efficiency of loading and unloading operations and the safety of equipment operation. Insufficient deviation correction or a malfunctioning collision avoidance system poses safety and efficiency risks.

[0003] Currently, tire crane travel control mainly relies on external reference points for positioning and sensor monitoring to achieve anti-collision and deviation correction functions. For example, Chinese invention patent publication number CN105438998A proposes a tire crane travel positioning, deviation correction, and anti-collision method. This method installs a laser scanner on the front wheel bracket of the tire crane and a column on the center line of the passageway behind the tire crane's lane. It corrects deviation by measuring the distance between multiple adjacent columns in real time, as well as the distance and angle between the column plane and the tire crane's travel direction. The detection range is divided into far zone, middle zone, and near zone to achieve graded anti-collision control.

[0004] However, this method primarily focuses on monitoring and locating the external environment, failing to incorporate the health status of the tires themselves into the travel drive control decision-making. In actual operation, the wear levels of the tires vary, resulting in differences in their mechanical properties. Uniform control commands can lead to overload and wear on tires in poor condition, while the potential of tires in good condition remains unutilized, thus affecting the overall machine's travel accuracy, control stability, and the overall tire lifespan.

[0005] Furthermore, since this method does not establish a dynamic relationship between tire health status and control allocation, the system cannot adaptively allocate compensation based on tire status under complex walking conditions. If the load of high and low state tires cannot be optimized in path tracking, it will lead to a decrease in walking stability and correction efficiency, and exacerbate the uneven wear of the tire group.

[0006] Furthermore, this method has limitations in collision avoidance safety control, as its control response fails to consider the physical limits of the tire actuators. Because it cannot comprehensively assess the state of each actuator, the system can only resort to a global emergency stop. This simplistic strategy not only disrupts operational continuity but may also cause overall machine vibration due to the extreme conditions of individual tires, creating potential safety hazards. Summary of the Invention

[0007] In view of this, in order to solve the problems mentioned in the background art, a method for driving the travel of a port container rubber-tired crane is proposed.

[0008] The objective of this invention can be achieved through the following technical solution: a port container tire crane travel drive control method, comprising: S1, based on real-time acquisition of the lateral deviation and heading angle deviation of the tire crane relative to a preset path, determining the required steering compensation amount and differential speed compensation amount through state space grid mapping.

[0009] S2. Determine the health status level of each tire based on its tread depth and cumulative running time.

[0010] S3. Under the condition of satisfying the physical execution constraints of each tire, the steering compensation amount and differential compensation amount are allocated to the speed and steering angle of each tire based on the health status level, generating the target steering angle and target speed change of each tire, so that the high health status tires undertake the dominant allocation, the medium health status tires undertake the basic allocation, and the low health status tires undertake the auxiliary allocation or do not undertake the allocation.

[0011] S4. Perform a safety check on the allocation results of each tire.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention solves the problem of one-size-fits-all control commands caused by individual tire performance differences by establishing a tire health status classification system based on tread depth and cumulative running time, and using this as the basis for allocating steering and differential compensation amounts. This method enables high-healthy tires to undertake the dominant control task, while medium- and low-healthy tires provide auxiliary support, thereby achieving precise matching between load and tire performance. This not only optimizes the overall machine's walking accuracy and control stability, but also promotes balanced wear of the tire group.

[0013] (2) This invention constructs a priority-coordinated safety control mechanism by integrating environmental monitoring of lidar and ultrasonic sensors with physical constraint status feedback of tire actuators. When an obstacle approaches, anti-collision control is executed first. At the same time, a precise degradation strategy is implemented by combining mechanical limit and real-time monitoring of motor current. This solves the problem of operation interruption and control oscillation caused by a single global emergency stop, and achieves a balance between safety protection and operation continuity. Attached Figure Description

[0014] 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.

[0015] Figure 1 This invention provides the steps of a port container tire crane travel drive control method.

[0016] Figure 2 This is a flowchart of the method for obtaining steering compensation and differential compensation in this invention.

[0017] Figure 3 This is a flowchart illustrating the method for obtaining the health status level of each tire in this invention. Detailed Implementation

[0018] 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.

[0019] Please see Figure 1 As shown, the present invention provides a method for driving the travel of a port container rubber-tired gantry crane, including: S1, determining the required steering compensation amount and differential speed compensation amount by real-time acquisition of the lateral deviation and heading angle deviation of the rubber-tired gantry crane relative to a preset path through state space grid mapping.

[0020] In one embodiment of the present invention, considering that the tire crane needs to maintain the stability and accuracy of the preset path during the travel process, lateral deviation and heading angle deviation are selected as the core control variables.

[0021] Lateral deviation directly reflects the degree of positional offset of the tire crane relative to the preset path, while heading angle deviation characterizes the degree of conformity between its attitude direction and the tangent direction of the path. Together, they constitute a complete state description of path tracking control. By using the state space grid mapping method, the path tracking problem is transformed into a real-time compensation problem of state vectors, thereby realizing the correction of the tire crane's travel trajectory.

[0022] Specifically, the lateral deviation and heading angle deviation are defined as follows: taking the geometric center of the tire crane as a reference point, the vertical distance from the reference point to the preset path is taken as the lateral deviation, and the angle between the centerline of the tire crane and the tangent direction of the preset path is taken as the heading angle deviation. The lateral deviation and heading angle deviation are both single values ​​at any control moment.

[0023] Further, please refer to Figure 2 As shown, in order to achieve path tracking compensation control based on the above-mentioned lateral deviation and heading angle deviation, it is necessary to obtain the corresponding steering compensation amount and differential compensation amount. The acquisition method includes: S11, establishing a 5×5 state space grid based on the maximum permissible lateral deviation and maximum permissible heading angle deviation of the tire crane.

[0024] Specifically, the method for establishing a 5×5 state space grid is as follows: First, define two coordinate axes of the state space: take the lateral deviation as the first dimension as the lateral deviation axis, and its value range is [-maximum permissible lateral deviation, +maximum permissible lateral deviation].

[0025] Using the heading angle deviation as the second dimension as the heading angle deviation axis, its value ranges from [-maximum permissible heading angle deviation, +maximum permissible heading angle deviation]. These two dimensions together constitute a two-dimensional state space.

[0026] The lateral deviation axis and the heading angle deviation axis are each divided into five equally spaced level intervals. The level intervals of the lateral deviation axis are marked from left to right as [negative deviation large, negative deviation small, zero, positive deviation small, positive deviation large]; the level intervals of the heading angle deviation axis are marked from bottom to top as [left deviation large, left deviation small, zero, right deviation small, right deviation large].

[0027] The two divided coordinate axes are combined to form a 5×5 state space grid.

[0028] It should be noted that when the lateral deviation or heading angle deviation exceeds the range of the state space grid, it indicates that the tire crane is in an abnormal and serious deviation state. In this state, the excess part will be treated as a boundary value, and a system warning signal will be generated immediately. This signal will be transmitted to the upper-level monitoring system.

[0029] S12. Based on the classification rules of lateral deviation and heading angle deviation, calculate the corresponding steering compensation amount and differential compensation amount for each grid node, and construct the steering compensation matrix and differential compensation matrix accordingly.

[0030] The classification rules are as follows: (a) The greater the lateral deviation, the greater the steering compensation; when the lateral deviation is negative or positive, the steering compensation direction is consistent with it.

[0031] (b) The greater the deviation in heading angle, the greater the differential compensation; when the yaw direction is left or right, the differential compensation direction is consistent with it.

[0032] (c) When both the lateral deviation and the heading angle deviation are large, the two types of compensation should be increased appropriately to make the correction faster.

[0033] (d) When the lateral deviation or heading angle deviation is small in negative deviation, small in positive deviation, small in left deviation, or small in right deviation, the compensation amount is taken at a medium level so that the control output changes smoothly under slight deviation and avoids abrupt compensation changes.

[0034] (e) When both the lateral deviation and the heading angle deviation are at zero, the compensation amount is taken as the minimum value, so that the control command transitions naturally in a state close to zero deviation, avoiding the occurrence of compensation direction reversal or jitter.

[0035] (f) All compensation amounts are limited to the safe limits allowed by the equipment.

[0036] It should be noted that the above-mentioned classification rules establish qualitative principles for control output. Based on these rules, the corresponding steering compensation and differential compensation amounts for each node in the state space grid must be calculated.

[0037] Specifically, a weighted synthesis method based on preset coefficients is adopted, wherein: the steering compensation amount is obtained by multiplying the lateral deviation by the first preset coefficient and then superimposing the result of multiplying the heading angle deviation by the second preset coefficient; the differential compensation amount is obtained by multiplying the heading angle deviation by the third preset coefficient and then superimposing the result of multiplying the lateral deviation by the fourth preset coefficient.

[0038] The values ​​of the first to fourth preset coefficients are dynamically adjusted according to the level classification rules.

[0039] For example, for a grid node with a lateral deviation level of large positive deviation and a heading angle deviation level of small right deviation, when calculating the steering compensation, because the lateral deviation level is large, its dominant coefficient, i.e., the first preset coefficient, takes a larger value of 0.5; because the heading angle deviation level is small, its auxiliary coefficient, i.e., the second preset coefficient, takes a smaller value of 0.1.

[0040] When calculating the differential compensation, since the heading angle deviation level is small, its dominant coefficient, namely the third preset coefficient, is taken as a small value of 0.2; at the same time, since the lateral deviation level is large, its auxiliary coefficient, namely the fourth preset coefficient, is taken as a medium value of 0.3.

[0041] The specific values ​​of all preset coefficients were obtained through parameter tuning experiments on simulation and physical platforms, and iterative optimization was carried out with the goal of minimizing path tracking error.

[0042] S13. The position of the lateral deviation and heading angle deviation in the state space grid is determined by real-time acquisition, and the real-time steering compensation amount and differential compensation amount are calculated from the steering compensation matrix and differential compensation matrix based on the bilinear interpolation algorithm.

[0043] Given that the state space grid is discrete, and the real-time acquired lateral deviation and heading angle deviation are continuous values, they may not necessarily fall exactly on the preset grid nodes. Simply taking the compensation amount of the nearest neighbor node would cause a step change in the control output.

[0044] Therefore, the method of numerical interpolation on a two-dimensional grid, namely the bilinear interpolation algorithm, can achieve a smooth transition of the compensation amount between adjacent grid nodes.

[0045] Specifically, based on the real-time detected lateral deviation and heading angle deviation values, the specific cell region in the state space grid is determined. This cell is surrounded by four nearest neighbor grid nodes, which correspond to the boundary values ​​of the level interval division on the lateral deviation axis and the heading angle deviation axis, respectively.

[0046] Read the compensation values ​​stored in these four nodes from the constructed steering compensation matrix and differential compensation matrix respectively.

[0047] For the lateral deviation direction, the relative position ratio of the current deviation value within the interval of that direction is calculated to obtain the lateral weighting coefficient; similarly, for the heading angle deviation direction, the relative position ratio of the current deviation value within the interval of that direction is calculated to obtain the heading angle weighting coefficient. Both weighting coefficients are dimensionless values ​​and are located in [0,1].

[0048] By using the compensation values ​​of the above four nodes and combining them with the two calculated weight coefficients, the real-time compensation amount under the current deviation state is finally obtained through linear weighted fusion.

[0049] S2. Determine the health status level of each tire based on its tread depth and cumulative running time.

[0050] In one embodiment of the present invention, considering that tires may experience performance differences due to varying degrees of wear during long-term operation, the evaluation is performed by acquiring tread depth sensor data and cumulative operating time counter data installed on each tire. Tread depth is a direct physical parameter characterizing the tire's remaining grip and safety margin, while cumulative operating time comprehensively reflects the tire's material fatigue aging and historical load conditions.

[0051] Based on these two key data points, a median-based comparison method was used to classify tire health status into three levels: high, medium, and low.

[0052] Further, please refer to Figure 3 As shown, the method for obtaining the health status level of each tire is as follows: calculate the median of all tread depths and cumulative running time. If the number of tires is even, take the average of the two median values.

[0053] The health status grade of each tire is determined based on the median tread depth and cumulative operating time according to the following rules:

[0054] High-health tires: Tires with a tread depth greater than or equal to the median tread depth of all tires and a cumulative running time less than or equal to the median cumulative running time of all tires indicate that they have good grip and a long remaining service life, making them suitable for bearing major control loads.

[0055] Tires in poor health condition: Tires with tread depth less than the median tread depth of all tires and cumulative running time greater than the median cumulative running time of all tires indicate that their grip is significantly reduced and they are aging. They should be avoided from being subjected to excessive loads.

[0056] Medium health condition tires: All tires other than high health condition tires and low health condition tires.

[0057] S3. Under the condition of satisfying the physical execution constraints of each tire, the steering compensation amount and differential compensation amount are allocated to the speed and steering angle of each tire based on the health status level, generating the target steering angle and target speed change of each tire, so that the high health status tires undertake the dominant allocation, the medium health status tires undertake the basic allocation, and the low health status tires undertake the auxiliary allocation or do not undertake the allocation.

[0058] In one embodiment of the present invention, considering the physical constraints such as mechanical limits of the tires and motor current, it is necessary to balance feasibility and safety in load distribution. Walking drive control is achieved through hierarchical distribution and real-time verification.

[0059] Furthermore, considering that the extreme steering requirements of the tire crane under complex working conditions may exceed the mechanical structure's bearing capacity, in order to avoid overload damage to the steering mechanism and the resulting risk of instability, the physical constraint conditions are satisfied as follows: obtain the real-time status of the mechanical limit switch of each tire steering mechanism, and when the mechanical limit switch is triggered, limit the maximum permissible target steering angle of the tire to the maximum permissible angle of the physical structure.

[0060] Meanwhile, the current value of each tire drive motor is collected in real time by the current sensor. When the current value exceeds the rated current of the motor, the target speed change of the tire is immediately reset to zero and the overcurrent protection mechanism is activated to prevent the motor from being overloaded and damaged, ensuring that the system operates within the physical safety boundary.

[0061] Furthermore, the specific method for allocating the steering compensation amount is as follows: if there are multiple tires in high health condition, the portion of the steering compensation amount that is greater than the average allocation amount is allocated to all tires in high health condition, and the remaining portion is allocated to tires in non-high health condition.

[0062] If there is only one high-healthy tire, the portion of the steering compensation that is greater than the distribution to other individual tires will be allocated to that high-healthy tire, the remaining portion will be allocated to the medium-healthy tires, and the low-healthy tires will not bear the steering compensation.

[0063] If there are no tires in high health condition but there are tires in medium health condition, the portion of the steering compensation that is greater than the average distribution will be allocated to the tires in medium health condition, and the remaining portion will be allocated to the tires in low health condition.

[0064] If all tires are in poor health, the steering compensation will be evenly distributed among the tires.

[0065] Furthermore, the specific method for allocating differential compensation is as follows: if there are tires in high health condition, then each tire in high health condition is allocated a differential compensation amount greater than the average allocation amount for all tires, and each tire in non-high health condition is allocated a differential compensation amount less than the average allocation amount.

[0066] If there are no tires in high health condition but there are tires in medium health condition, then calculate the average distribution of differential compensation across all tires.

[0067] Each tire in a medium health condition is assigned a differential compensation amount greater than the average allocation, and each tire in a low health condition is assigned a differential compensation amount less than the average allocation, ensuring that the sum of the allocations for all tires equals the differential compensation amount.

[0068] If all tires are in poor health, then each tire is allocated an equal amount of differential compensation.

[0069] It should be noted that if the number of tires is 1, then the tire is considered to be in high health and is allocated the full amount of steering compensation or differential compensation.

[0070] Due to the complex and ever-changing port operating environment, there is a risk of personnel, equipment, and other obstacles encroaching on the rubber-tired gantry crane's travel path. To ensure operational safety, environmental safety controls must be implemented concurrently during the allocation of steering compensation and differential compensation. These controls specifically include:

[0071] The surrounding environment of the tire crane is monitored in real time by using lidar and ultrasonic sensors to obtain the distance to obstacles. The lidar and ultrasonic sensor array installed on the main body of the tire crane scans and monitors the dynamics of its surrounding environment in real time to obtain the distance information of the nearest obstacle.

[0072] The distance to the obstacle is compared with a preset safety threshold. When the distance to any obstacle is lower than the safety threshold, the allocation of steering compensation and differential compensation is immediately interrupted, and a collision avoidance control command is generated and sent to the actuator. The collision avoidance control command includes an emergency stop command or a deceleration to a safe speed command.

[0073] The safety threshold is determined by complying with the mandatory requirements for safe distances of industrial vehicles in port equipment safety regulations.

[0074] When the distance to obstacles in all directions remains above the safety threshold for a preset recovery time, the system automatically resumes the normal allocation and execution of steering compensation and differential compensation.

[0075] S4. Perform a safety check on the allocation results of each tire.

[0076] Because tire-mounted cranes are subject to physical limitations such as mechanical structure and motor performance during actual operation, directly allocating compensation based on health status may cause individual tires to exceed their execution capabilities, leading to equipment damage or control instability. Therefore, it is necessary to perform safety verification on the allocation results for each tire to ensure that the final control commands for each tire are within its physical execution capabilities.

[0077] Furthermore, the specific method for performing the safety verification is to obtain the status of the mechanical limit switches of each tire steering mechanism and the real-time current value of the drive motor.

[0078] When the target steering angle of any tire causes the mechanical limit switch of that tire to be triggered, the target steering angle is cut off to the maximum allowable value that does not trigger the limit switch, and the excess is redistributed to the tires that have not triggered the limit switch in order of health status from high to low, to ensure that the steering action does not exceed the mechanical structure’s capacity, while prioritizing the use of tires with better health status to share the extra load.

[0079] If the change in the target speed of any tire causes the real-time current value to exceed its rated current value, the change in the target speed of that tire will be reduced proportionally to ensure that the current value does not exceed the rated current value. The reduced portion will be evenly distributed among tires of the same health status to prevent motor overload damage. At the same time, load balancing among tires of the same status will prevent excessive load from being transferred to a single tire.

[0080] The ratio is defined as the ratio of the motor's rated current value to the real-time current value before the over-limit occurred.

[0081] If, after the above redistribution, a tire still triggers the mechanical limit switch or the current exceeds the limit, the distribution range is expanded. The compensation amount is distributed proportionally among all tires that have not triggered the constraint, in descending order of health status level, to ensure operation within the physical safety boundary and prevent system failure due to local overload.

[0082] When the number of redistribution attempts reaches a preset threshold (e.g., 5 times) and all physical constraints are still not met, a system-level protection mechanism is activated: the overall steering compensation and differential compensation are reduced by the same proportion to lower control requirements; at the same time, a system degradation operation signal is generated to allow the tire crane to continue working in conservative mode; and a tire maintenance warning is issued to the operator to prompt timely inspection or replacement of the problematic tire.

[0083] Given that personnel and equipment safety is the highest priority principle in port operations, the real-time performance and reliability of collision avoidance control must take precedence over the allocation and verification process of tire target steering angle and speed changes.

[0084] Therefore, when a collision avoidance control command is generated, environmental safety control is executed first, and safety verification is suspended to ensure the rapid response capability and decision certainty of the control system in emergency situations. When allocation is resumed, that is, when environmental safety control is released and the distance of all obstacles remains higher than the safety threshold for 5-10 seconds, safety verification is reactivated and the allocation process continues based on the allocation state before the interruption.

[0085] In summary, this invention firstly uses a state-space grid mapping method to accurately calculate the required steering and differential compensation amounts based on the lateral and heading angle deviations of the tire crane; secondly, it scientifically assesses the tire health status level by combining the tread depth and cumulative operating time of each tire; furthermore, under the condition of satisfying physical execution constraints, it implements a differentiated load allocation strategy based on health status, enabling tires with high health status to undertake dominant allocation, tires with medium health status to undertake basic allocation, and tires with low health status to undertake auxiliary allocation or be exempt from allocation; simultaneously, through a dual guarantee mechanism of environmental safety control and execution safety verification, it ensures the safe and stable operation of the system in complex port environments.

[0086] Those skilled in the art will recognize that the algorithmic steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0087] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0088] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0089] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the travel drive of a port container rubber-tired gantry crane, characterized in that, include: S1. Based on the real-time acquisition of the lateral deviation and heading angle deviation of the tire crane relative to the preset path, the required steering compensation and differential compensation are determined by state space grid mapping. S2. Determine the health status level of each tire based on its tread depth and cumulative running time. S3. Under the condition of satisfying the physical execution constraints of each tire, the steering compensation amount and differential compensation amount are allocated to the speed and steering angle of each tire based on the health status level, generating the target steering angle and target speed change of each tire, so that the high health status tires undertake the dominant allocation, the medium health status tires undertake the basic allocation, and the low health status tires undertake the auxiliary allocation or do not undertake the allocation. S4. Perform a safety check on the allocation results of each tire.

2. The port container rubber-tired crane travel drive control method as described in claim 1, characterized in that, When performing the method as described in claim 1, it further includes environmental safety control, specifically including: The environment around the tire crane is monitored in real time using lidar and ultrasonic sensors to obtain the distance to obstacles. Compare the distance to the obstacle with a preset safety threshold; When the distance to any obstacle is lower than the safety threshold, the allocation of steering compensation and differential compensation is immediately interrupted, and a collision avoidance control command is generated and sent to the actuator. The collision avoidance control command includes an emergency stop command or a deceleration to a safe speed command. Once the distance to all obstacles remains above the safety threshold for a predetermined duration, the allocation and execution of steering compensation and differential compensation will resume.

3. The method for controlling the travel drive of a port container rubber-tired gantry crane as described in claim 1, characterized in that, The lateral deviation and heading angle deviation are specifically as follows: Using the geometric center of the tire crane as a reference point, the vertical distance from the reference point to the preset path is taken as the lateral deviation, and the angle between the centerline of the tire crane and the tangent direction of the preset path is taken as the heading angle deviation. The lateral deviation and the heading angle deviation are both single values ​​at any control moment.

4. The method for controlling the travel drive of a port container rubber-tired gantry crane as described in claim 1, characterized in that, The method for obtaining the steering compensation amount and the differential compensation amount is as follows: A state space grid is established based on the maximum permissible lateral deviation and the maximum permissible heading angle deviation of the rubber-tired gantry crane. Based on the classification rules of lateral deviation and heading angle deviation, the corresponding steering compensation and differential compensation are calculated for each grid node, and the steering compensation matrix and differential compensation matrix are constructed accordingly. The position of the lateral deviation and heading angle deviation in the state space grid is determined by real-time acquisition, and the real-time steering compensation amount and differential compensation amount are calculated from the steering compensation matrix and differential compensation matrix based on the bilinear interpolation algorithm.

5. The port container rubber-tired crane travel drive control method as described in claim 1, characterized in that, The method for obtaining the health status level of each tire is as follows: Read the tread depth sensor data and cumulative running time counter for each tire; Calculate the median of all tread depths and cumulative running times. If the number of tires is even, take the average of the two median values. The health status grade of each tire is determined based on the median tread depth and cumulative operating time according to the following rules: High health tires: Tires with tread depth greater than or equal to the median tread depth of all tires and cumulative running time less than or equal to the median cumulative running time of all tires; Tires in poor health: Tires with tread depth less than the median tread depth of all tires and cumulative running time greater than the median cumulative running time of all tires; Medium health condition tires: All tires other than high health condition tires and low health condition tires.

6. The port container rubber-tired crane travel drive control method as described in claim 1, characterized in that, The specific physical execution constraints for each tire are as follows: The real-time status of the mechanical limit switch of each tire steering mechanism is obtained. When the mechanical limit switch is triggered, the maximum permissible target steering angle of the tire is limited to the maximum permissible angle of the physical structure of the steering mechanism. Obtain the real-time current value of each tire drive motor. When the real-time current value exceeds the rated current value marked on the motor nameplate, set the maximum permissible target speed change of that tire to zero.

7. The port container rubber-tired crane travel drive control method as described in claim 1, characterized in that, The specific method for allocating steering compensation in S3 is as follows: If there are multiple tires in high health condition, the portion of the steering compensation that is greater than the average distribution will be allocated to all tires in high health condition, and the remaining portion will be allocated to tires in non-high health condition. If there is only a single high-healthy tire, the portion of the steering compensation that is greater than the distribution to other single tires will be allocated to that high-healthy tire, the remaining portion will be allocated to the medium-healthy tires, and the low-healthy tires will not bear the steering compensation. If there are no high-healthy tires but there are medium-healthy tires, the portion of the steering compensation that is greater than the average distribution will be allocated to the medium-healthy tires, and the remaining portion will be allocated to the low-healthy tires. If all tires are in poor health, the steering compensation will be evenly distributed among the tires.

8. The method for controlling the travel drive of a port container rubber-tired gantry crane as described in claim 1, characterized in that, The specific method for allocating differential compensation in S3 is as follows: If there are tires in high health condition, then each tire in high health condition is allocated a differential compensation amount greater than the average allocation amount for all tires, and each tire in non-high health condition is allocated a differential compensation amount less than the average allocation amount. If there are no tires in high health condition but there are tires in medium health condition, then calculate the average distribution of differential compensation across all tires. Allocate a differential compensation amount greater than the average allocation to each tire in medium health condition, and allocate a differential compensation amount less than the average allocation to each tire in poor health condition, while ensuring that the sum of the allocation amounts for all tires equals the differential compensation amount. If all tires are in poor health, then each tire is allocated an equal amount of differential compensation.

9. The method for controlling the travel drive of a port container rubber-tired gantry crane as described in claim 1, characterized in that, The safety verification of the tire allocation results includes: Obtain the status of the mechanical limit switches of each tire steering mechanism and the real-time current value of the drive motor; When the target steering angle of any tire causes the mechanical limit switch of that tire to be triggered, the target steering angle is truncated to the maximum allowable value that does not trigger the limit switch, and the excess is redistributed to the tires that have not triggered the limit switch in order of health status level from high to low. If the change in the target speed of any tire causes the real-time current value to exceed its rated current value, the change in the target speed of that tire will be reduced proportionally so that the current value does not exceed the rated current value, and the reduced portion will be evenly distributed among tires of the same health condition level. If, after redistribution, a tire still triggers the mechanical limit switch or the current exceeds the rated current value, the compensation amount is proportionally distributed among the tires that have not triggered the constraint, in descending order of health status level, to ensure that the load on each tire does not exceed its maximum allowable value. When the number of redistribution attempts reaches the preset threshold and still fails to meet all physical constraints, the overall steering compensation and differential compensation are reduced proportionally, and a system degradation operation signal is generated. At the same time, a tire maintenance warning is issued to the operator.

10. The port container rubber-tired crane travel drive control method as described in claim 9, characterized in that, The security verification process also includes: When a collision avoidance control command is generated, environmental safety control is executed first, and the execution safety verification is paused. When allocation is resumed, the execution safety verification is reactivated, and the allocation process continues based on the allocation state before the interruption.

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