Dual drive forklift drive control method and system

Abstract

The application discloses a double-drive forklift driving control method and system, and relates to the technical field of electric forklift control. The method comprises the following steps: acquiring vehicle operation input information, vehicle current speed information, left driving motor actual speed and right driving motor actual speed in a current control period; determining speed deviation information according to the left and right driving motor actual speeds; determining a current driving condition according to the vehicle operation input information and the vehicle current speed information; generating a basic driving control instruction, and determining driving correction information according to the current driving condition and the speed deviation information; performing driving inhibition / compensation, inside / outside differentiation correction and instruction speed closed-loop correction in the conditions of straight-line acceleration, turning acceleration and uniform speed driving, respectively; and generating left and right driving motor control instructions after limiting the amplitudes according to preset correction boundary information. Thus, the straight-line driving precision and the steering control stability of the double-drive forklift can be improved.

Description

Technical Field

[0001] This application relates to the field of electric forklift control technology, and in particular to a dual-drive forklift drive control method and system. Background Technology

[0002] With the increasing demands for operational efficiency and positioning accuracy in warehousing, logistics, manufacturing, and loading / unloading operations, electric forklifts are gradually evolving towards electronic control, low-speed precision, and high stability. Dual-drive forklifts, with their respective drive wheels providing independent driving force, offer advantages in load capacity, site adaptability, and steering flexibility, making them widely used in narrow aisle handling, rack alignment, pallet retrieval, and heavy-duty transfers. In these scenarios, vehicles frequently need to perform actions such as starting, straight-line driving, steering, braking, and fine-tuning. The stability of the vehicle's driving posture, its ability to maintain straight-line stability, and the consistency of its handling response directly affect fork alignment accuracy and operational safety.

[0003] In related technologies, the driving control of dual-drive forklifts typically generates drive control commands based on driving operation signals, target vehicle speed, or steering requirements, and executes vehicle driving actions through left and right drive units. However, in actual operation, forklifts often operate in environments with low speeds, heavy loads, frequent starts and stops, and complex ground conditions. Factors such as vehicle weight distribution, load bias, tire adhesion conditions, mechanical transmission errors, and differences in drive component response can all affect the vehicle's driving state. Especially during straight-line driving, the vehicle is susceptible to deviations in driving direction due to inconsistent left and right drive responses and external disturbances. During steering, the vehicle needs to balance steering agility, driving smoothness, and vehicle stability. Existing control methods, which mainly rely on preset control parameters or relatively fixed drive distribution logic, often struggle to maintain stable and consistent driving performance under different loads, road surfaces, and driving conditions. This can lead to problems such as decreased straight-line driving accuracy, increased fork positioning deviation, uncoordinated steering response, and vehicle swaying under complex operating conditions.

[0004] Therefore, in the driving control of dual-drive forklifts, the lack of consistency in drive response under different working conditions, the susceptibility of straight-line driving accuracy to disturbances, and the poor coordination of steering control have become urgent problems to be solved. Summary of the Invention

[0005] This application provides a drive control method and system for a dual-drive forklift, aiming to solve the problems of insufficient consistency of drive response under different working conditions, easy influence of disturbance on straight-line driving accuracy, and poor coordination of steering control in the driving control of dual-drive forklifts in the prior art.

[0006] A first aspect includes a dual-drive forklift drive control method, the method comprising: Acquire the target dual-drive forklift's vehicle operation input information, current vehicle speed information, actual speed of the left drive motor, and actual speed of the right drive motor within the current control cycle; Based on the actual speed of the left drive motor and the actual speed of the right drive motor, determine the speed deviation information between the left and right drive motors. The speed deviation information includes the speed difference and speed difference change information in the current control cycle. Based on the vehicle operation input information and the vehicle current speed information, the current driving condition of the target dual-drive forklift is determined. The current driving condition is one of a plurality of preset driving conditions, which include at least straight-line acceleration condition, turning acceleration condition and constant speed driving condition. Based on the vehicle operation input information, generate basic drive control commands corresponding to the left drive motor and the right drive motor; Based on the current driving conditions and the speed deviation information, determine the corresponding drive correction information for the left and right drive motors. The drive correction information includes acceleration correction information and / or speed correction information. When the current driving condition is a straight-line acceleration condition, the drive correction information is used to suppress the drive motor with a higher speed and to compensate the drive motor with a lower speed. When the current driving condition is a turning acceleration condition, the drive output of the inner drive motor and the outer drive motor is differentially corrected based on the drive correction information so that the target acceleration and / or target speed of the outer drive wheel is greater than the target acceleration and / or target speed of the inner drive wheel. When the current driving condition is constant speed driving condition, the command speeds of the left drive motor and the right drive motor are corrected in a closed loop based on the drive correction information to suppress the accumulation of driving deviation between the left and right drive wheels. The drive correction information is limited according to the preset correction boundary information, and the basic drive control command is corrected according to the limited drive correction information to generate the left drive motor control command and the right drive motor control command. The left drive motor is controlled according to the left drive motor control command, and the right drive motor is controlled according to the right drive motor control command.

[0007] Optionally, in the above scheme, determining the speed deviation information between the left and right drive motors based on the actual speeds of the left and right drive motors includes: The speed difference for the current control cycle is determined based on the actual speeds of the left and right drive motors within the current control cycle. Obtain the historical speed difference between the actual speed of the left drive motor and the actual speed of the right drive motor in the previous control cycle; Based on the speed difference of the current control cycle and the historical speed difference, determine the speed difference change information; The speed deviation information is generated based on the speed difference in the current control cycle and the speed difference change information.

[0008] In the above scheme, optionally, the speed difference change information includes the speed difference change amount and the speed difference change rate; determining the drive correction information corresponding to the left and right drive motors based on the current driving conditions and the speed deviation information includes: Based on the speed difference corresponding to multiple control cycles, determine the cumulative speed difference information; Obtain the closed-loop control parameters corresponding to the target dual-drive forklift, the closed-loop control parameters including proportional control parameters, integral control parameters and derivative control parameters; The closed-loop correction amount is determined based on the speed difference of the current control cycle, the cumulative speed difference information, and the speed difference change rate. The closed-loop correction amount is adapted according to the current driving conditions to generate the acceleration correction information and / or the speed correction information.

[0009] Optionally, in the above scheme, determining the current driving condition of the target dual-drive forklift based on the vehicle operation input information and the vehicle's current speed information includes: Based on the vehicle operation input information and the vehicle current speed information, the target speed information, acceleration demand information, and steering operation information are determined. Based on the target speed information, the acceleration demand information, and the vehicle's current speed information, the speed change state of the target dual-drive forklift is determined; Based on the steering operation information, determine the steering state of the target dual-drive forklift; The current driving condition is determined based on the speed change state and the steering state.

[0010] Optionally, in the above scheme, determining the current driving condition based on the speed change state and the steering state includes: If the steering state meets the straight-going determination condition and the speed change state meets the acceleration determination condition, the current driving condition is determined to be a straight-going acceleration condition. If the steering state meets the steering determination condition and the speed change state meets the acceleration determination condition, the current driving condition is determined to be a turning acceleration condition, and the inner drive motor and the outer drive motor are determined according to the steering state. If the speed change state meets the constant speed determination condition, the current driving condition is determined to be a constant speed driving condition.

[0011] Optionally, in the above scheme, when the current driving condition is a straight-line acceleration condition, suppressing the drive motor with a higher speed and compensating the drive motor with a lower speed based on the drive correction information includes: Based on the speed difference of the current control cycle, determine the drive motor with the larger speed and the drive motor with the smaller speed among the left drive motor and the right drive motor; Based on the closed-loop correction amount, determine the acceleration suppression amplitude and the acceleration compensation amplitude; Based on the acceleration suppression amplitude, the basic acceleration command corresponding to the high-speed drive motor is reduced and corrected to obtain the first corrected acceleration command; Based on the acceleration compensation amplitude, the basic acceleration command corresponding to the drive motor with the smaller speed is improved and corrected to obtain a second corrected acceleration command; Based on the first and second corrected acceleration commands, control commands for the left and right drive motors under straight-line acceleration conditions are generated.

[0012] Optionally, in the above scheme, when the current driving condition is a turning acceleration condition, the differential correction of the drive output of the inner drive motor and the outer drive motor based on the drive correction information includes: Based on the steering state, determine the turning direction of the target dual-drive forklift; Based on the turning direction, determine the inner drive motor and the outer drive motor among the left drive motor and the right drive motor; Based on the acceleration demand information and the speed deviation information, determine the turning drive allocation information; Based on the turning drive allocation information, the basic drive control commands of the inner drive motor and the outer drive motor are differentiated and modified to obtain inner drive control commands and outer drive control commands. The target acceleration and / or target speed corresponding to the outer drive control command is greater than the target acceleration and / or target speed corresponding to the inner drive control command.

[0013] Optionally, in the above scheme, when the current driving condition is a constant speed driving condition, performing closed-loop correction on the command speeds of the left and right drive motors based on the drive correction information includes: Based on the speed deviation information within multiple consecutive control cycles, determine the cumulative trend of the travel distance deviation between the left and right drive wheels; Based on the cumulative trend of the driving distance deviation, determine the speed fine-tuning information corresponding to the left drive motor and the right drive motor; Based on the speed fine-tuning information, the basic speed commands corresponding to the left drive motor and the right drive motor are corrected to obtain the corrected speed command for the left drive motor and the corrected speed command for the right drive motor. Based on the speed correction commands from the left and right drive motors, the accumulation of travel distance deviation between the left and right drive wheels during constant speed driving is suppressed.

[0014] In the above scheme, optionally, the preset correction boundary information is determined in the following way: Obtain the vehicle weight information, rated load information, motor parameter information, and drive safety constraint information of the target dual-drive forklift; Based on the vehicle's self-weight information, the rated load information, and the motor parameter information, candidate information for the correction boundary is determined; Based on the driving safety constraint information, the candidate information for the modified boundary is subjected to safety constraint processing to obtain the preset modified boundary information; The preset correction boundary information includes at least one of the following: upper limit of acceleration correction amplitude, lower limit of acceleration correction amplitude, upper limit of speed correction amplitude, and lower limit of speed correction amplitude. The upper limit of acceleration correction amplitude is not greater than the maximum allowable acceleration of the drive motor, and the lower limit of acceleration correction amplitude is not less than zero.

[0015] Secondly, a dual-drive forklift drive control system, the system comprising: The information acquisition module is used to acquire the vehicle operation input information, current vehicle speed information, actual speed of the left drive motor and actual speed of the right drive motor of the target dual-drive forklift in the current control cycle. The deviation determination module is used to determine the speed deviation information between the left and right drive motors based on the actual speed of the left drive motor and the actual speed of the right drive motor. The speed deviation information includes the speed difference and speed difference change information in the current control cycle. The working condition determination module is used to determine the current driving condition of the target dual-drive forklift based on the vehicle operation input information and the vehicle current speed information. The current driving condition is one of a plurality of preset driving conditions, which include at least straight-line acceleration condition, turning acceleration condition and constant speed driving condition. The basic instruction generation module is used to generate basic drive control instructions corresponding to the left drive motor and the right drive motor based on the vehicle operation input information. The drive correction module is used to determine the drive correction information corresponding to the left and right drive motors based on the current driving conditions and the speed deviation information. The drive correction information includes acceleration correction information and / or speed correction information. The drive correction module includes a straight-line correction unit, a turning correction unit, and a constant-speed correction unit. The straight-line correction unit, when the current driving condition is a straight-line acceleration condition, suppresses the drive of the higher-speed drive motor and compensates for the lower-speed drive motor based on the drive correction information. The turning correction unit, when the current driving condition is a turning acceleration condition, differentiates the drive output of the inner and outer drive motors based on the drive correction information to ensure that the target acceleration and / or target speed of the outer drive wheel is greater than that of the inner drive wheel. The constant-speed correction unit, when the current driving condition is a constant-speed driving condition, performs closed-loop correction on the command speeds of the left and right drive motors based on the drive correction information to suppress the accumulation of driving deviations between the left and right drive wheels. The amplitude limiting output module is used to limit the drive correction information according to the preset correction boundary information, and to correct the basic drive control command according to the amplitude limiting drive correction information to generate the left drive motor control command and the right drive motor control command. The drive control module is used to control the left drive motor according to the left drive motor control command and to control the right drive motor according to the right drive motor control command.

[0016] Compared with the prior art, this application has at least the following beneficial effects: This application, based on further analysis and research of existing technical problems, recognizes that existing technologies for driving control of dual-drive forklifts suffer from insufficient consistency in drive response under different operating conditions, susceptibility to disturbances affecting straight-line driving accuracy, and poor steering coordination. By acquiring the vehicle operation input information, current vehicle speed information, actual speed of the left drive motor, and actual speed of the right drive motor of the target dual-drive forklift within the current control cycle, the vehicle controller can simultaneously grasp the driving operation requirements, the actual driving state of the vehicle, and the true response states of the left and right drive motors. Based on this, speed deviation information is determined according to the actual speeds of the left and right drive motors, allowing for the quantification of inconsistencies in the actual responses between the left and right drive motors. Furthermore, the current driving condition is determined based on the vehicle operation input information and current vehicle speed information, and drive correction information is determined based on the current driving condition and speed deviation information, ensuring that drive correction no longer relies solely on... Instead of a fixed allocation logic, it can adapt to different operating conditions such as straight-line acceleration, cornering acceleration, and constant-speed driving. During straight-line acceleration, it suppresses the drive motor with higher speed and compensates for the drive motor with lower speed, causing the actual speeds of the left and right drive motors to become more consistent, thus reducing the risk of veering off course during straight-line driving. During cornering acceleration, it performs differentiated corrections on the inner and outer drive motors, ensuring that the target acceleration and / or speed of the outer drive wheel is greater than that of the inner drive wheel, matching the left and right drive outputs to the vehicle's cornering requirements and improving steering coordination. During constant-speed driving, it performs closed-loop correction on the commanded speeds of the left and right drive motors, suppressing the continuous accumulation of driving deviations between the left and right drive wheels. Simultaneously, it limits the drive correction information based on preset correction boundary information, preventing overshoot, jitter, or drift caused by excessive correction. Therefore, this application can address the problems of insufficient consistency in drive response, susceptibility to disturbances in straight-line driving accuracy, and poor coordination in steering control under different operating conditions by achieving dynamic coordinated control of left and right drive outputs, thereby improving the straight-line driving accuracy, fork positioning stability, and steering control stability of dual-drive forklifts. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a dual-drive forklift drive control method provided in one embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] In one embodiment, such as Figure 1As shown, a drive control method for a dual-drive forklift is provided. The target dual-drive forklift can be an electric forklift with drive motors on both the left and right sides. The left drive motor drives the left drive wheel, and the right drive motor drives the right drive wheel. The vehicle controller executes the drive control process according to a preset control cycle. The preset control cycle can be determined based on the computing power of the vehicle controller, the communication cycle of the motor controller, and the low-speed driving control accuracy of the vehicle. For example, it can be set to 10ms, or it can be adjusted according to the vehicle model.

[0020] The vehicle controller acquires vehicle operation input information, current vehicle speed information, actual speed of the left drive motor, and actual speed of the right drive motor within the current control cycle. The vehicle operation input information may include at least one of the following: accelerator pedal opening, steering wheel angle, reversing command, braking input, target driving direction, and target speed request. The current vehicle speed information can be determined by a vehicle speed sensor, motor speed conversion results, or wheel speed acquisition results. The actual speeds of the left and right drive motors can be fed back from the left and right drive motor controllers, respectively, or obtained by speed detection components installed on the corresponding drive wheels or transmission mechanisms. Through the above acquisition and processing, the vehicle controller obtains basic data for determining the vehicle's driving status and left / right drive response status within the current control cycle.

[0021] The vehicle controller determines the speed deviation information between the left and right drive motors based on their actual speeds. Specifically, the vehicle controller uses the difference between the actual speeds of the left and right drive motors as the speed difference for the current control cycle, and combines this difference with the speed difference from the previous control cycle to determine the speed difference change information. This speed deviation information reflects the consistency of the left and right drive motors' operation within the current control cycle. If the speed difference persists or its trend continues to increase, it indicates that the left and right drive wheels may experience deviations in driving distance or vehicle posture during actual driving.

[0022] The vehicle controller determines the current driving condition of the target dual-drive forklift based on vehicle operation input information and the vehicle's current speed information. The current driving condition can be determined from multiple preset driving conditions, including at least straight-line acceleration, turning acceleration, and constant-speed driving. Specifically, when the steering wheel angle is small and the vehicle requires acceleration, it can be identified as straight-line acceleration; when the steering wheel angle reaches the turning threshold and the vehicle requires acceleration, it can be identified as turning acceleration; and when the difference between the target speed and the vehicle's current speed is small and the vehicle speed change is relatively smooth, it can be identified as constant-speed driving. Through this condition identification process, the vehicle controller can obtain the current driving condition for selecting a drive correction strategy.

[0023] The vehicle controller also generates basic drive control commands for the left and right drive motors based on vehicle operation input information. These basic drive control commands may include at least one of a basic target speed command, a basic target acceleration command, or a basic torque command. They characterize the initial control quantities of the left and right drive motors generated based on driver operation or the vehicle's target driving requirements, without considering left and right drive response deviation corrections. Subsequently, the vehicle controller determines drive correction information for the left and right drive motors based on the current driving conditions and speed deviation information. This drive correction information may include acceleration correction information and / or speed correction information. This drive correction information is used to correct the basic drive control commands, ensuring that the left and right drive outputs match the current driving requirements and actual deviation states.

[0024] When the current driving condition is straight-line acceleration, the vehicle controller determines the drive motors with higher and lower speeds based on speed deviation information. It then suppresses the drive motor with higher speed and compensates for the drive motor with lower speed based on drive correction information. For example, when the actual speed of the left drive motor is greater than that of the right drive motor, the target acceleration or speed corresponding to the left drive motor can be reduced, while the target acceleration or speed corresponding to the right drive motor can be increased; conversely, when the actual speed of the right drive motor is greater than that of the left drive motor, the opposite correction is performed. This process helps to make the left and right drive speeds more consistent during straight-line acceleration.

[0025] When the current driving condition is a turning acceleration condition, the vehicle controller can determine the inner and outer drive motors based on the steering wheel angle or steering operation direction, and differentiate the drive outputs of the inner and outer drive motors by combining drive correction information, so that the target acceleration and / or target speed of the outer drive wheels is greater than that of the inner drive wheels. Since the driving radius corresponding to the outer drive wheels is larger than that corresponding to the inner drive wheels when the vehicle turns, the above-mentioned differential correction can make the left and right drive outputs conform to the turning motion requirements, avoiding steering incoordination caused by simple synchronous control.

[0026] Under the current driving condition of constant speed, the vehicle controller performs closed-loop correction on the commanded speeds of the left and right drive motors based on drive correction information. During constant speed driving, the instantaneous speed difference between the left and right drive motors may be small, but if this speed difference persists for a long time, it will lead to an accumulation of deviation in the travel distance between the left and right drive wheels. The vehicle controller can make small adjustments to the commanded speeds of the left and right drive motors based on the speed deviation information over multiple consecutive control cycles, thereby suppressing the continuous accumulation of driving deviation.

[0027] Before generating the control commands for the left and right drive motors, the vehicle controller performs amplitude limiting processing on the drive correction information based on preset correction boundary information. The preset correction boundary information may include at least one of the following: an upper limit for acceleration correction amplitude, a lower limit for acceleration correction amplitude, an upper limit for speed correction amplitude, and a lower limit for speed correction amplitude. This amplitude limiting processing prevents excessive drive correction from causing overshoot, vehicle vibration, drift, or cargo swaying, and also prevents instability in the control program caused by abnormal correction amplitudes. The vehicle controller then modifies the basic drive control commands based on the amplitude-limited drive correction information to obtain the left and right drive motor control commands, which are then sent to the left and right drive motors for execution, respectively.

[0028] This embodiment determines speed deviation information by collecting the actual speeds of the left and right drive motors, and performs condition-specific corrections to the basic drive control commands based on the current driving conditions. This reduces the difference in left and right drive response during straight-line acceleration, meets the different movement requirements of the inner and outer drive wheels during cornering acceleration, and suppresses the accumulation of driving deviations during constant-speed driving. At the same time, by using preset correction boundary information to limit the drive correction information, the risk of vibration and drift caused by overcompensation can be reduced, thereby improving the straight-line driving accuracy, fork positioning stability, and steering coordination of the dual-drive forklift.

[0029] In one possible embodiment, the vehicle controller reads the actual speeds of the left and right drive motors respectively within the current control cycle. The actual speeds of the left and right drive motors can be motor rotational speeds or linear speeds of the drive wheels calculated based on motor rotational speed, reduction ratio, and drive wheel radius. To ensure comparability of the left and right data, the vehicle controller can synchronously acquire the speed data from both sides within the same control cycle, or perform time alignment processing on the asynchronously fed-out speed data to obtain the actual speeds of the left and right drive motors corresponding to the current control cycle.

[0030] The vehicle controller determines the speed difference for the current control cycle based on the actual speeds of the left and right drive motors. Specifically, the speed difference is calculated by subtracting the actual speed of the right drive motor from the actual speed of the left drive motor. A positive speed difference indicates that the actual speed of the left drive motor is greater than that of the right drive motor; a negative speed difference indicates that the actual speed of the right drive motor is greater than that of the left drive motor; and a speed difference close to zero indicates that the actual speeds of the left and right drive motors are essentially the same. Through this process, the vehicle controller obtains the current speed difference used to determine the direction and magnitude of the deviation in the left and right drive response.

[0031] The vehicle controller acquires the historical speed difference between the actual speeds of the left and right drive motors in the previous control cycle, and determines the speed difference change information based on the speed difference in the current control cycle and the historical speed difference. This speed difference change information can include the amount of change in the speed difference in the current control cycle relative to the previous control cycle, or it can include the rate of change of the speed difference per unit control cycle. Through this speed difference change information, the vehicle controller can not only determine the current magnitude of the deviation between the left and right drive motors, but also determine whether the deviation is trending towards increasing, decreasing, or remaining stable.

[0032] The vehicle controller generates speed deviation information based on the speed difference and its variation within the current control cycle. This speed deviation information serves as a common input for subsequent closed-loop correction calculations, straight-line acceleration suppression compensation, differentiated drive allocation during cornering, and fine-tuning of constant-speed driving. In practical applications, the vehicle controller can also filter the speed difference and its variation to reduce the impact of road bumps, momentary slippage, or speed sensor noise on control stability.

[0033] This embodiment uses the speed difference in the current control cycle and the speed difference change information between adjacent control cycles to jointly characterize the left and right drive response states, enabling the vehicle controller to simultaneously identify the deviation direction, deviation amplitude, and deviation change trend. Compared to the method of generating left and right drive commands based solely on a fixed drive ratio, this processing can provide more accurate feedback for subsequent closed-loop correction, thereby improving straight-line driving accuracy and reducing the risk of accumulated driving deviation.

[0034] In one possible embodiment, the speed difference change information includes the amount of speed difference change and the rate of speed difference change. The amount of speed difference change can be determined by the difference between the speed difference in the current control cycle and the historical speed difference in the previous control cycle, and the rate of speed difference change can be determined by the relationship between the amount of speed difference change and the control cycle duration. The control cycle duration can be a fixed period, such as 10ms, or it can be the time interval between two adjacent control calculations actually recorded by the vehicle controller.

[0035] The vehicle controller determines the cumulative speed difference information based on the speed differences corresponding to multiple control cycles. Specifically, the vehicle controller can accumulate the speed differences of multiple consecutive control cycles within a preset time window, or it can weight the speed differences of multiple consecutive control cycles according to the duration of the control cycle to obtain the cumulative speed difference information. The cumulative speed difference information is used to characterize the persistence of the speed deviation between the left and right drive motors over a period of time, and it can reflect the trend of the gradual formation of the deviation in the travel distance between the left and right drive wheels.

[0036] The vehicle controller acquires the closed-loop control parameters corresponding to the target dual-drive forklift. These closed-loop control parameters include proportional control parameters, integral control parameters, and derivative control parameters. These parameters can be calibrated offline before the vehicle leaves the factory based on vehicle weight information, rated load information, motor parameter information, and overall vehicle response characteristics, and then stored in the vehicle controller. Different closed-loop control parameters can be set for different vehicle models, rated loads, or drive motor configurations to match the drive correction intensity with the vehicle's actual response capability.

[0037] The vehicle controller determines the closed-loop correction amount based on the speed difference, cumulative speed difference information, and speed difference change rate of the current control cycle. The speed difference of the current control cycle reflects the current deviation magnitude, the cumulative speed difference information reflects the long-term deviation accumulation, and the speed difference change rate reflects the rate of deviation change. The vehicle controller can process the above information based on proportional control parameters, integral control parameters, and derivative control parameters respectively to form the closed-loop correction amount. The closed-loop correction amount can be understood as the basic correction amplitude used to reduce the left and right drive deviations.

[0038] The vehicle controller adapts the closed-loop correction amount according to the current driving conditions, generating acceleration correction information and / or speed correction information. Specifically, under straight-line acceleration conditions, the closed-loop correction amount can be converted into acceleration suppression amplitude and acceleration compensation amplitude; under cornering acceleration conditions, the closed-loop correction amount can be combined with the cornering drive distribution relationship to form differentiated correction information for the inner and outer drive motors; under constant speed driving conditions, the closed-loop correction amount can be converted into speed fine-tuning information for the left and right drive motors. Through the above adaptation processing, the same type of speed deviation feedback can generate different forms of drive correction information according to different driving conditions.

[0039] This embodiment comprehensively processes the current speed difference, accumulated speed difference information, and speed difference change rate by using proportional control parameters, integral control parameters, and derivative control parameters. This enables the drive correction information to respond to the current left and right drive deviations while suppressing long-term deviation accumulation and rapid deviation changes. At the same time, by adapting the closed-loop correction amount according to the current driving conditions, it can avoid conflicts in control objectives caused by a single correction method being applied to different scenarios such as straight driving, turning, and constant speed, thereby improving control stability and adaptability to different driving conditions.

[0040] In one possible embodiment, the vehicle controller determines target speed information, acceleration demand information, and steering operation information based on vehicle operation input information and current vehicle speed information. Target speed information can be determined by accelerator pedal opening, throttle input, target vehicle speed given by the vehicle controller, or operating mode; acceleration demand information can be determined based on the difference between target speed information and current vehicle speed information, or by combining the trend of accelerator pedal opening changes; steering operation information can be determined by steering wheel angle, steering angle sensor signal, steering throttle input, or steering controller output.

[0041] The vehicle controller determines the speed change state of the target dual-drive forklift based on target speed information, acceleration demand information, and the vehicle's current speed information. The speed change state can include acceleration, constant speed, deceleration, or a stationary state. For example, when the target speed is higher than the vehicle's current speed and the accelerator pedal opening is greater than a preset opening, the vehicle can be determined to be in an acceleration state; when the difference between the target speed and the vehicle's current speed is within a preset speed difference range, and the rate of change of the vehicle's current speed is less than a preset rate of change, the vehicle can be determined to be in a constant speed state. Through this processing, the vehicle controller obtains the speed change state used to identify the vehicle's longitudinal motion.

[0042] The vehicle controller determines the steering state of the target dual-drive forklift based on steering operation information. Specifically, it compares the steering wheel angle or steering control amount with a preset steering threshold. If the steering wheel angle is less than or equal to the preset straight-ahead threshold, the steering state meets the straight-ahead determination condition; if the steering wheel angle is greater than the preset steering threshold, the steering state meets the steering determination condition. The vehicle controller can also determine the vehicle's turning direction based on the sign of the steering wheel angle or the steering control direction, providing a basis for the subsequent determination of the inner and outer drive motors.

[0043] The vehicle controller determines the current driving condition based on speed change status and steering status. Specifically, speed change status is used to distinguish whether the vehicle needs to accelerate or maintain a constant speed, while steering status is used to distinguish whether the vehicle is traveling straight or turning. By combining the speed change status and steering status, the vehicle controller can determine the current driving condition and use this current driving condition as the basis for selecting a drive correction strategy.

[0044] This embodiment identifies the current driving condition by combining target speed information, acceleration demand information, vehicle current speed information, and steering operation information, enabling the vehicle controller to distinguish between different control scenarios such as straight-line acceleration, cornering acceleration, and constant-speed driving. As a result, subsequent drive corrections can adopt different control methods for different conditions, avoiding the problem that fixed drive allocation logic is difficult to adapt to low-speed, heavy-load, frequent start-stop, and steering operation environments, thereby improving vehicle handling consistency.

[0045] In one possible embodiment, the vehicle controller determines the current driving condition as a straight-line acceleration condition when the steering state meets the straight-line determination condition and the speed change state meets the acceleration determination condition. The straight-line determination condition can be that the steering wheel angle is less than a preset straight-line angle threshold, or the steering control amount is within a preset median range; the acceleration determination condition can be that the target speed is greater than the vehicle's current speed, or the accelerator pedal opening is greater than a preset acceleration opening. Through this determination, the vehicle controller obtains the identification result of the straight-line acceleration condition, and subsequently employs a control method combining left and right drive deviation suppression and compensation.

[0046] When the vehicle controller determines the current driving condition as a turning acceleration condition if both the steering state and speed change meet the acceleration criteria, it identifies the inner and outer drive motors based on the steering state. The steering criteria can be a steering wheel angle greater than a preset steering angle threshold or a steering control amount exceeding a preset steering range. If the steering state indicates a left turn, the left drive motor is identified as the inner drive motor, and the right drive motor as the outer drive motor; conversely, if the steering state indicates a right turn, the right drive motor is identified as the inner drive motor, and the left drive motor as the outer drive motor. Through this process, the vehicle controller obtains the identification results for the turning acceleration condition and the inner and outer drive motors.

[0047] When the speed change meets the constant speed determination criteria, the vehicle controller determines the current driving condition as a constant speed driving condition. The constant speed determination criteria can be that the difference between the target speed and the vehicle's current speed is less than a preset speed difference threshold, and the rate of change of the vehicle's current speed over multiple consecutive control cycles is less than a preset rate of change threshold. In operating modes requiring improved straight-line driving accuracy, the constant speed straight-line driving state can also be determined by combining the steering status with the straight-line determination criteria. Through this determination, the vehicle controller obtains the identification result of the constant speed driving condition, and can subsequently perform small closed-loop corrections to the commanded speeds of the left and right drive motors.

[0048] This embodiment subdivides the current driving condition by determining straight-line driving, turning, acceleration, and constant speed conditions. In the turning acceleration condition, it further determines the inner and outer drive motors, enabling the vehicle controller to form clear control entry points for different conditions. This process is beneficial for prioritizing the improvement of left and right drive consistency when driving straight and prioritizing the matching of inner and outer drive outputs when turning, thereby taking into account both straight-line driving accuracy and steering coordination.

[0049] In one possible embodiment, when the current driving condition is a straight-line acceleration condition, the vehicle controller determines the drive motor with the greater speed and the drive motor with the smaller speed between the left and right drive motors based on the speed difference in the current control cycle. Specifically, when the speed difference in the current control cycle indicates that the actual speed of the left drive motor is greater than the actual speed of the right drive motor, the left drive motor is determined to be the drive motor with the greater speed, and the right drive motor is determined to be the drive motor with the smaller speed; when the speed difference in the current control cycle indicates that the actual speed of the right drive motor is greater than the actual speed of the left drive motor, the right drive motor is determined to be the drive motor with the greater speed, and the left drive motor is determined to be the drive motor with the smaller speed.

[0050] The vehicle controller determines the acceleration suppression amplitude and acceleration compensation amplitude based on the closed-loop correction value. The acceleration suppression amplitude is used to reduce the base acceleration command corresponding to the drive motor with a higher speed, while the acceleration compensation amplitude is used to increase the base acceleration command corresponding to the drive motor with a lower speed. The acceleration suppression amplitude and acceleration compensation amplitude can be the same, or they can be set to different amplitudes according to the vehicle's weight, rated load, current vehicle speed, road surface adhesion conditions, or motor response capabilities. When the vehicle is heavily loaded, at low speed, or under poor road surface adhesion conditions, the acceleration compensation amplitude or acceleration suppression amplitude can be reduced to decrease vehicle body sway.

[0051] The vehicle controller reduces the base acceleration command corresponding to the drive motor with a higher speed based on the acceleration suppression amplitude, resulting in a first corrected acceleration command; and increases the base acceleration command corresponding to the drive motor with a lower speed based on the acceleration compensation amplitude, resulting in a second corrected acceleration command. For example, if the actual speed of the left drive motor is greater than that of the right drive motor, the vehicle controller can reduce the base acceleration command for the left drive motor and increase the base acceleration command for the right drive motor, so that the actual speeds of the left and right drive motors gradually converge; if the actual speed of the right drive motor is greater than that of the left drive motor, the opposite correction is performed.

[0052] The vehicle controller generates control commands for the left and right drive motors under straight-line acceleration conditions based on the first and second corrected acceleration commands. If the first corrected acceleration command corresponds to the left drive motor, it is used as part of the left drive motor control command, and the second corrected acceleration command is used as part of the right drive motor control command; if the first corrected acceleration command corresponds to the right drive motor, the configuration is reversed. Through this process, the vehicle controller obtains the left and right drive control results under straight-line acceleration conditions.

[0053] In this embodiment, the drive motor with the larger speed and the drive motor with the smaller speed are determined based on the actual speed difference between the left and right drive motors during straight-line acceleration. The larger speed side is suppressed and the smaller speed side is compensated, which can reduce the difference in left and right drive response in real time during start-up and acceleration. As a result, the vehicle can reduce deviation during straight-line acceleration, reduce the formation speed of the difference in travel distance between the left and right drive wheels, and improve fork alignment and straight-line driving stability.

[0054] In one possible embodiment, when the current driving condition is a turning acceleration condition, the vehicle controller determines the turning direction of the target dual-drive forklift based on the steering state. The steering state may include the steering wheel angle direction, the steering wheel angle magnitude, and the steering control amount. The vehicle controller can determine whether the vehicle is turning left or right based on the positive or negative direction of the steering wheel angle, and use this turning direction as the basis for determining the inner drive motor and the outer drive motor.

[0055] The vehicle controller determines the inner and outer drive motors in the left and right drive motors based on the turning direction. For example, when the target dual-drive forklift turns left, the left drive wheel is on the inside of the turn, so the left drive motor is the inner drive motor and the right drive motor is the outer drive motor; when the target dual-drive forklift turns right, the right drive wheel is on the inside of the turn, so the right drive motor is the inner drive motor and the left drive motor is the outer drive motor. Through this process, the vehicle controller obtains the inner and outer motor correspondence for differentiated drive control.

[0056] The vehicle controller determines the turning drive allocation information based on acceleration demand information and speed deviation information. Acceleration demand information reflects the driver's or vehicle controller's demand for longitudinal acceleration, while speed deviation information reflects the current actual speed deviation between the left and right drive motors. Turning drive allocation information may include at least one of the following: target acceleration of the outer drive motor, target acceleration of the inner drive motor, target speed of the outer drive motor, and target speed of the inner drive motor. When determining the turning drive allocation information, the vehicle controller ensures that the target acceleration and / or target speed of the outer drive wheels are greater than the target acceleration and / or target speed of the inner drive wheels to accommodate the larger travel radius of the outer drive wheels during cornering.

[0057] Based on the cornering drive allocation information, the vehicle controller performs differentiated modifications to the basic drive control commands for the inner and outer drive motors, resulting in inner and outer drive control commands. These differentiated modifications can either increase the target acceleration or speed of the outer drive motor based on the basic drive control commands, or decrease the target acceleration or speed of the inner drive motor based on the basic drive control commands, or simultaneously increase the outer motor's acceleration and decrease the inner motor's speed. Through this process, the vehicle controller obtains left and right drive control results that conform to the motion relationship between the inner and outer wheels during cornering acceleration.

[0058] In this embodiment, the inner and outer drive motors are determined according to the turning direction during the cornering acceleration condition. The cornering drive distribution information is generated by combining the acceleration demand information and speed deviation information, so that the outer drive wheel obtains a target acceleration and / or target speed greater than that of the inner drive wheel. As a result, the problem of mismatch between the left and right drive output and the vehicle's steering demand during cornering can be improved, and the steering response and vehicle movement coordination can be enhanced.

[0059] In one possible embodiment, when the current driving condition is constant speed driving, the vehicle controller determines the cumulative trend of the travel distance deviation between the left and right drive wheels based on the speed deviation information over multiple consecutive control cycles. Specifically, the vehicle controller can accumulate the speed differences over multiple consecutive control cycles, or it can combine the control cycle duration to convert the speed differences into estimated distance differences between the left and right drive wheels, thereby obtaining the cumulative trend of the travel distance deviation. If the speed differences over multiple consecutive control cycles are basically in the same direction, it indicates that the left and right drive wheels may be forming a continuous travel distance deviation.

[0060] The vehicle controller determines the speed fine-tuning information for the left and right drive motors based on the cumulative trend of the driving distance deviation. This speed fine-tuning information can include at least one of the following: the increase in speed of the left drive motor, the decrease in speed of the left drive motor, the increase in speed of the right drive motor, and the decrease in speed of the right drive motor. Since vehicle speed changes should be smooth under constant speed driving conditions, the amplitude of the speed fine-tuning information can be smaller than the acceleration correction amplitude under straight-line acceleration conditions to avoid frequent corrections that could cause vehicle vibration or a decline in driving experience.

[0061] Based on the speed fine-tuning information, the vehicle controller corrects the base speed commands corresponding to the left and right drive motors, resulting in corrected speed commands for the left and right drive motors. For example, when the cumulative trend of travel distance deviation indicates that the travel distance of the left drive wheel is gradually greater than that of the right drive wheel, the base speed command for the left drive motor can be slightly reduced, or the base speed command for the right drive motor can be slightly increased; conversely, when the travel distance of the right drive wheel is gradually greater than that of the left drive wheel, the speed fine-tuning is performed in the opposite direction.

[0062] The vehicle controller controls the left and right drive motors based on the speed correction commands from the left and right drive motors, thus suppressing the cumulative deviation in travel distance between the left and right drive wheels during constant-speed driving. In practical applications, the vehicle controller can set a small slope for the speed fine-tuning information to avoid sudden changes in the correction speed; it can also pause the correction when the speed deviation information is within a preset allowable range to reduce control oscillations.

[0063] In this embodiment, instead of using large acceleration compensation as the main correction method under constant speed driving conditions, the cumulative trend of driving distance deviation is determined based on the speed deviation information in multiple continuous control cycles, and a small closed-loop correction is made to the basic speed command of the left and right drive motors. As a result, the accumulation of distance deviation during long-term constant speed driving can be suppressed, the risk of chronic vehicle deviation can be reduced, and the straight-line keeping ability and fork positioning accuracy can be improved.

[0064] In one possible embodiment, the vehicle controller or calibration device acquires the target dual-drive forklift's vehicle weight information, rated load information, motor parameter information, and drive safety constraint information. The vehicle weight information characterizes the vehicle's basic mass in an unloaded state; the rated load information characterizes the range of cargo weight the vehicle is allowed to carry; the motor parameter information may include at least one of the drive motor's maximum permissible acceleration, maximum permissible speed, maximum permissible torque, rated power, and response delay; and the drive safety constraint information may include at least one of vehicle stability constraints, tire adhesion constraints, cargo anti-sway constraints, and controller output constraints.

[0065] Based on vehicle weight, rated load, and motor parameters, candidate correction boundary information is determined. Specifically, when the vehicle weight is large or the rated load is high, a relatively gentle acceleration correction amplitude can be set to avoid vehicle swaying under heavy load. When the maximum allowable acceleration of the motor is high and the vehicle stability requirements are met, the upper limit of the acceleration correction amplitude can be appropriately increased to improve the speed deviation correction response speed. Through this process, candidate correction boundary information that matches the parameters of the target dual-drive forklift can be obtained.

[0066] Based on the drive safety constraint information, the candidate correction boundary information is processed to obtain preset correction boundary information. Safety constraint processing may include limiting the upper limit of the acceleration correction amplitude to no greater than the maximum allowable acceleration of the drive motor, limiting the lower limit of the acceleration correction amplitude to no less than zero, limiting the speed correction amplitude within the allowable range for smooth vehicle operation, and limiting the slope of the correction amplitude change. The preset correction boundary information can be determined and stored in the vehicle controller during the vehicle's factory calibration phase, or it can be updated during maintenance calibration or software upgrades.

[0067] The preset correction boundary information includes at least one of the following: upper limit of acceleration correction amplitude, lower limit of acceleration correction amplitude, upper limit of speed correction amplitude, and lower limit of speed correction amplitude. The upper limit of acceleration correction amplitude is not greater than the maximum allowable acceleration of the drive motor, and the lower limit of acceleration correction amplitude is not less than zero. The correction amplitude here represents the magnitude of compensation or suppression. The direction of compensation and suppression is determined by the current driving conditions and speed deviation information. Therefore, a lower limit of correction amplitude not less than zero will not restrict the controller from performing reduced or increased correction. By imposing upper and lower limits on the correction amplitude, abnormal drive correction amplitude, program division by zero anomalies, compensation overshoot, and vehicle drift and severe vibration under complex conditions can be prevented.

[0068] This embodiment determines preset correction boundary information based on vehicle weight information, rated load information, motor parameter information, and drive safety constraint information, and uses this preset correction boundary information to limit the drive correction amplitude, so that the left and right drive closed-loop correction has sufficient response capability and will not exceed the allowable range of motor and vehicle stability; thereby, the stability and safety of the control algorithm under heavy load, bumpy, low speed and frequent start-stop conditions can be improved.

[0069] In one embodiment, a control method for improving the maneuverability and straight-line driving accuracy of a dual-drive forklift is provided, including: real-time acquisition of the actual speeds of the left and right drive motors, and calculation of the current cycle speed difference Δv(t) and the periodic static difference Δvt0. Δvt1 and the rate of change of deviation Δv(t) / t; the output is calculated using PID control: u(t) = KPΔv(t) + KI +KDΔv(t) / t, where KP, KI, and KD are the proportional, integral, and derivative coefficients calibrated based on the vehicle's weight and load, and t is the control period; according to the driving conditions (straight-line acceleration, turning acceleration, constant speed), u(t) is used to dynamically compensate or suppress the acceleration and commanded speed of the left and right drive wheels, and upper and lower limits for compensation / suppression are set to avoid overshoot and jitter.

[0070] In this embodiment, during straight-line acceleration: if the left drive speed > the right drive speed, then the left drive acceleration a1 = u(t) (suppressed), and the right drive acceleration a2 = u(t). =u(t) (compensation), and vice versa.

[0071] In this embodiment, during cornering acceleration: the acceleration of the outer drive wheel is greater than that of the inner drive wheel, i.e., aout > ain.

[0072] In this embodiment, when traveling at a constant speed: a small closed-loop compensation is performed on the commanded speeds of the left and right wheels based on the speed difference Δv(t) to eliminate the cumulative distance deviation.

[0073] In this embodiment, the compensation / suppression value has an upper limit and a lower limit, which are obtained through factory calibration. However, the upper limit does not exceed the maximum allowable acceleration of the motor, and the lower limit is not less than zero, to prevent program division by zero errors and vehicle body drift and severe shaking under complex working conditions.

[0074] This embodiment uses PID closed-loop dynamic correction to correct the speed difference between the two wheels, suppressing deviation at its source and significantly improving straightness.

[0075] Full-condition compatibility: Covers straight driving, turning, and constant speed scenarios. Automatically distributes inner and outer wheel acceleration when turning, making the steering wheel more responsive and improving handling.

[0076] High stability: The compensation value is limited to avoid overshoot and jitter, making it suitable for complex working conditions such as bumps and heavy loads.

[0077] Low implementation cost: No new hardware is required; it can be implemented simply by upgrading the software algorithm, making it suitable for mass applications.

[0078] In one possible embodiment, the dual-drive forklift drive control system can be located in the vehicle controller of the target dual-drive forklift, or it can be implemented collaboratively by the vehicle controller, the left drive motor controller, and the right drive motor controller. The system includes an information acquisition module, a deviation determination module, a working condition determination module, a basic instruction generation module, a drive correction module, a limit output module, and a drive control module. Each module can be implemented through software programs, controller hardware circuits, or a combination of software and hardware.

[0079] The information acquisition module is used to acquire the vehicle operation input information, current vehicle speed information, actual speed of the left drive motor, and actual speed of the right drive motor of the target dual-drive forklift within the current control cycle. Specifically, the information acquisition module can obtain relevant data from the accelerator pedal sensor, steering wheel angle sensor, vehicle speed detection unit, left drive motor controller, and right drive motor controller, and perform sampling synchronization and validity verification on the acquired data to obtain the control input data within the current control cycle.

[0080] The deviation determination module determines the speed deviation information between the left and right drive motors based on their actual speeds. This module calculates the speed difference in the current control cycle and combines it with historical speed differences from the previous control cycle to determine speed difference changes, thereby generating speed deviation information characterizing the consistency deviation in the left and right drive responses. This speed deviation information is then passed to the drive correction module for subsequent drive correction information determination.

[0081] The operating condition determination module is used to determine the current driving condition of the target dual-drive forklift based on vehicle operation input information and current vehicle speed information. The module first determines the target speed information, acceleration demand information, and steering operation information, and then identifies the current driving condition based on speed change and steering status. The current driving condition is one of several preset driving conditions, which include at least straight-line acceleration, turning acceleration, and constant-speed driving. The module can also determine the inner and outer drive motors during turning acceleration.

[0082] The basic instruction generation module generates basic drive control instructions for the left and right drive motors based on vehicle operation input information. These basic drive control instructions can include basic speed, basic acceleration, or basic torque instructions. The generated basic drive control instructions are sent to the limiting output module or drive correction module as the basis for subsequent correction processing.

[0083] The drive correction module determines the corresponding drive correction information for the left and right drive motors based on the current driving conditions and speed deviation information. The drive correction module includes a straight-line correction unit, a turning correction unit, and a constant-speed correction unit. The straight-line correction unit, when the current driving condition is straight-line acceleration, uses the drive correction information to suppress the drive of the drive motor with higher speed and compensate for the drive of the drive motor with lower speed. The turning correction unit, when the current driving condition is turning acceleration, uses the drive correction information to differentiate the drive output of the inner and outer drive motors, ensuring that the target acceleration and / or target speed of the outer drive wheel is greater than that of the inner drive wheel. The constant-speed correction unit, when the current driving condition is constant-speed driving, uses the drive correction information to perform closed-loop correction on the command speeds of the left and right drive motors to suppress the accumulation of driving deviations between the left and right drive wheels.

[0084] The amplitude limiting output module limits the drive correction information according to preset correction boundary information, and then corrects the basic drive control commands based on the amplitude-limited drive correction information to generate left and right drive motor control commands. The amplitude limiting output module can limit the acceleration correction amplitude, speed correction amplitude, and correction change slope to ensure that the output left and right drive motor control commands meet the requirements of motor capability and vehicle stability. The drive control module controls the left drive motor according to the left drive motor control command and controls the right drive motor according to the right drive motor control command, thereby completing the coordinated control of the left and right drive motors.

[0085] This embodiment achieves a coordinated control process of left and right drive actual speed feedback, speed deviation closed-loop correction, working condition drive control, and correction of amplitude limiting output through data transmission between the information acquisition module, deviation determination module, working condition determination module, basic instruction generation module, drive correction module, amplitude limiting output module, and drive control module. The system can improve the straight-line driving accuracy, steering coordination, and driving stability under complex working conditions of dual-drive forklifts through control logic without additional changes to the forklift's mechanical structure. It has the advantages of low cost and suitability for mass application.

[0086] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A drive control method for a dual-drive forklift, characterized in that, The method includes: Acquire the target dual-drive forklift's vehicle operation input information, current vehicle speed information, actual speed of the left drive motor, and actual speed of the right drive motor within the current control cycle; Based on the actual speed of the left drive motor and the actual speed of the right drive motor, determine the speed deviation information between the left and right drive motors. The speed deviation information includes the speed difference and speed difference change information in the current control cycle. Based on the vehicle operation input information and the vehicle current speed information, the current driving condition of the target dual-drive forklift is determined. The current driving condition is one of a plurality of preset driving conditions, which include at least straight-line acceleration condition, turning acceleration condition and constant speed driving condition. Based on the vehicle operation input information, generate basic drive control commands corresponding to the left drive motor and the right drive motor; Based on the current driving conditions and the speed deviation information, determine the corresponding drive correction information for the left and right drive motors. The drive correction information includes acceleration correction information and / or speed correction information. When the current driving condition is a straight-line acceleration condition, the drive correction information is used to suppress the drive motor with a higher speed and to compensate the drive motor with a lower speed. When the current driving condition is a turning acceleration condition, the drive output of the inner drive motor and the outer drive motor is differentially corrected based on the drive correction information so that the target acceleration and / or target speed of the outer drive wheel is greater than the target acceleration and / or target speed of the inner drive wheel. When the current driving condition is constant speed driving condition, the command speeds of the left drive motor and the right drive motor are corrected in a closed loop based on the drive correction information to suppress the accumulation of driving deviation between the left and right drive wheels. The drive correction information is limited according to the preset correction boundary information, and the basic drive control command is corrected according to the limited drive correction information to generate the left drive motor control command and the right drive motor control command. The left drive motor is controlled according to the left drive motor control command, and the right drive motor is controlled according to the right drive motor control command.

2. The dual-drive forklift drive control method according to claim 1, characterized in that, The step of determining the speed deviation information between the left and right drive motors based on the actual speeds of the left and right drive motors includes: The speed difference for the current control cycle is determined based on the actual speeds of the left and right drive motors within the current control cycle. Obtain the historical speed difference between the actual speed of the left drive motor and the actual speed of the right drive motor in the previous control cycle; Based on the speed difference of the current control cycle and the historical speed difference, determine the speed difference change information; The speed deviation information is generated based on the speed difference in the current control cycle and the speed difference change information.

3. The dual-drive forklift drive control method according to claim 2, characterized in that, The speed difference change information includes the speed difference change amount and the speed difference change rate; the step of determining the drive correction information corresponding to the left and right drive motors based on the current driving conditions and the speed deviation information includes: Based on the speed difference corresponding to multiple control cycles, determine the cumulative speed difference information; Obtain the closed-loop control parameters corresponding to the target dual-drive forklift, the closed-loop control parameters including proportional control parameters, integral control parameters and derivative control parameters; The closed-loop correction amount is determined based on the speed difference of the current control cycle, the cumulative speed difference information, and the speed difference change rate. The closed-loop correction amount is adapted according to the current driving conditions to generate the acceleration correction information and / or the speed correction information.

4. The dual-drive forklift drive control method according to claim 1, characterized in that, Determining the current driving condition of the target dual-drive forklift based on the vehicle operation input information and the vehicle's current speed information includes: Based on the vehicle operation input information and the vehicle current speed information, the target speed information, acceleration demand information, and steering operation information are determined. Based on the target speed information, the acceleration demand information, and the vehicle's current speed information, the speed change state of the target dual-drive forklift is determined; Based on the steering operation information, determine the steering state of the target dual-drive forklift; The current driving condition is determined based on the speed change state and the steering state.

5. The dual-drive forklift drive control method according to claim 4, characterized in that, Determining the current driving condition based on the speed change state and the steering state includes: If the steering state meets the straight-going determination condition and the speed change state meets the acceleration determination condition, the current driving condition is determined to be a straight-going acceleration condition. If the steering state meets the steering determination condition and the speed change state meets the acceleration determination condition, the current driving condition is determined to be a turning acceleration condition, and the inner drive motor and the outer drive motor are determined according to the steering state. If the speed change state meets the constant speed determination condition, the current driving condition is determined to be a constant speed driving condition.

6. The dual-drive forklift drive control method according to claim 3, characterized in that, When the current driving condition is a straight-line acceleration condition, the method of suppressing the drive motor with a higher speed and compensating the drive motor with a lower speed based on the drive correction information includes: Based on the speed difference of the current control cycle, determine the drive motor with the larger speed and the drive motor with the smaller speed among the left drive motor and the right drive motor; Based on the closed-loop correction amount, determine the acceleration suppression amplitude and the acceleration compensation amplitude; Based on the acceleration suppression amplitude, the basic acceleration command corresponding to the high-speed drive motor is reduced and corrected to obtain the first corrected acceleration command; Based on the acceleration compensation amplitude, the basic acceleration command corresponding to the drive motor with the smaller speed is improved and corrected to obtain a second corrected acceleration command; Based on the first and second corrected acceleration commands, control commands for the left and right drive motors under straight-line acceleration conditions are generated.

7. The dual-drive forklift drive control method according to claim 5, characterized in that, When the current driving condition is a turning acceleration condition, the drive output of the inner drive motor and the outer drive motor are differentiated and corrected based on the drive correction information, including: Based on the steering state, determine the turning direction of the target dual-drive forklift; Based on the turning direction, determine the inner drive motor and the outer drive motor among the left drive motor and the right drive motor; Based on the acceleration demand information and the speed deviation information, determine the turning drive allocation information; Based on the turning drive allocation information, the basic drive control commands of the inner drive motor and the outer drive motor are differentiated and modified to obtain inner drive control commands and outer drive control commands. The target acceleration and / or target speed corresponding to the outer drive control command is greater than the target acceleration and / or target speed corresponding to the inner drive control command.

8. The dual-drive forklift drive control method according to claim 3, characterized in that, When the current driving condition is a constant speed driving condition, the closed-loop correction of the command speeds of the left and right drive motors based on the drive correction information includes: Based on the speed deviation information within multiple consecutive control cycles, determine the cumulative trend of the travel distance deviation between the left and right drive wheels; Based on the cumulative trend of the driving distance deviation, determine the speed fine-tuning information corresponding to the left drive motor and the right drive motor; Based on the speed fine-tuning information, the basic speed commands corresponding to the left drive motor and the right drive motor are corrected to obtain the corrected speed command for the left drive motor and the corrected speed command for the right drive motor. Based on the speed correction commands from the left and right drive motors, the accumulation of travel distance deviation between the left and right drive wheels during constant speed driving is suppressed.

9. The dual-drive forklift drive control method according to any one of claims 1 to 8, characterized in that, The preset correction boundary information is determined in the following way: Obtain the vehicle weight information, rated load information, motor parameter information, and drive safety constraint information of the target dual-drive forklift; Based on the vehicle's self-weight information, the rated load information, and the motor parameter information, candidate information for the correction boundary is determined; Based on the driving safety constraint information, the candidate information for the modified boundary is subjected to safety constraint processing to obtain the preset modified boundary information; The preset correction boundary information includes at least one of the following: upper limit of acceleration correction amplitude, lower limit of acceleration correction amplitude, upper limit of speed correction amplitude, and lower limit of speed correction amplitude. The upper limit of acceleration correction amplitude is not greater than the maximum allowable acceleration of the drive motor, and the lower limit of acceleration correction amplitude is not less than zero.

10. A dual-drive forklift drive control system, characterized in that, The system includes: The information acquisition module is used to acquire the vehicle operation input information, current vehicle speed information, actual speed of the left drive motor and actual speed of the right drive motor of the target dual-drive forklift in the current control cycle. The deviation determination module is used to determine the speed deviation information between the left and right drive motors based on the actual speed of the left drive motor and the actual speed of the right drive motor. The speed deviation information includes the speed difference and speed difference change information in the current control cycle. The working condition determination module is used to determine the current driving condition of the target dual-drive forklift based on the vehicle operation input information and the vehicle current speed information. The current driving condition is one of a plurality of preset driving conditions, which include at least straight-line acceleration condition, turning acceleration condition and constant speed driving condition. The basic instruction generation module is used to generate basic drive control instructions corresponding to the left drive motor and the right drive motor based on the vehicle operation input information. The drive correction module is used to determine the drive correction information corresponding to the left and right drive motors based on the current driving conditions and the speed deviation information. The drive correction information includes acceleration correction information and / or speed correction information. The drive correction module includes a straight-line correction unit, a turning correction unit, and a constant-speed correction unit. The straight-line correction unit, when the current driving condition is a straight-line acceleration condition, suppresses the drive of the higher-speed drive motor and compensates for the lower-speed drive motor based on the drive correction information. The turning correction unit, when the current driving condition is a turning acceleration condition, differentiates the drive output of the inner and outer drive motors based on the drive correction information to ensure that the target acceleration and / or target speed of the outer drive wheel is greater than that of the inner drive wheel. The constant-speed correction unit, when the current driving condition is a constant-speed driving condition, performs closed-loop correction on the command speeds of the left and right drive motors based on the drive correction information to suppress the accumulation of driving deviations between the left and right drive wheels. The amplitude limiting output module is used to limit the drive correction information according to the preset correction boundary information, and to correct the basic drive control command according to the amplitude limiting drive correction information to generate the left drive motor control command and the right drive motor control command. The drive control module is used to control the left drive motor according to the left drive motor control command and to control the right drive motor according to the right drive motor control command.

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