Vehicle inching control method, controller, system and vehicle

Abstract

The invention discloses a vehicle inching control method, a controller, a system and a vehicle, and the method comprises the steps: obtaining the actual vehicle speed and the target vehicle speed of the vehicle in real time under the condition that the vehicle is in an inching control mode; determining a difference value between the target vehicle speed and the actual vehicle speed as a vehicle speed deviation; determining a vehicle speed deviation change rate based on the change condition of the vehicle speed deviation along with time; based on a preset fuzzy self-adaptive PID controller, the target torque of a clutch of the vehicle is determined according to the vehicle speed deviation and the vehicle speed deviation change rate, and PID control parameters of the fuzzy self-adaptive PID controller are determined according to the vehicle speed deviation and the fuzzy quantity corresponding to the vehicle speed deviation change rate; and the engagement state of the clutch is adjusted according to the target torque so that the vehicle can run according to the target vehicle speed. The target torque of the clutch is dynamically adjusted through the fuzzy self-adaptive PID controller according to the vehicle speed deviation and the change rate of the vehicle speed deviation, self-adaptive control over complex road conditions is achieved, and the stability and precision of vehicle speed control are improved.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and more specifically to a method, controller, system, and vehicle for micro-motion control of a vehicle. Background Technology

[0002] Existing agricultural vehicles often need to travel at extremely low and stable speeds in agricultural operations such as tilling, sowing, harvesting, and site relocation to ensure operational quality. In these situations, acceleration is typically not achieved through throttle, but rather by relying on engine idle torque to achieve low-speed creeping, a technique commonly referred to in the industry as micro-motion control or creep control.

[0003] In low gear, with light throttle, or at idle, drivers typically maintain a semi-engaged (slipping) state of the clutch plates by frequently and precisely manipulating the clutch pedal. By adjusting the degree of slippage, they indirectly control the power transmitted to the drive wheels, thus achieving the desired low speed. This manual control method has significant limitations. It demands a high level of experience and skill from the driver, and prolonged operation can easily lead to driver fatigue. Furthermore, due to the inaccuracy of driver feedback control, the vehicle speed is prone to fluctuations when road resistance changes, making it difficult to maintain stability and directly affecting the uniformity of sowing, harvesting results, and other operational quality.

[0004] Therefore, the vehicle micro-motion control methods used in the prior art have poor reliability when facing complex operating conditions. Summary of the Invention

[0005] The purpose of this application is to provide a method, controller, system, and vehicle for micro-motion control of a vehicle, in order to solve the problem that the vehicle micro-motion control methods used in the prior art have poor reliability when facing complex working conditions.

[0006] To achieve the above objectives, the first aspect of this application provides a method for micro-motion control of a vehicle, the method comprising: When the vehicle is in micro-motion control mode, the actual vehicle speed and target vehicle speed are acquired in real time. The difference between the target speed and the actual speed is defined as the speed deviation. The rate of change of vehicle speed deviation is determined based on the change of vehicle speed deviation over time. Based on a preset fuzzy adaptive PID controller, the target torque of the vehicle's clutch is determined according to the vehicle speed deviation and the rate of change of the vehicle speed deviation. The PID control parameters of the fuzzy adaptive PID controller are determined according to the fuzzy quantities corresponding to the vehicle speed deviation and the rate of change of the vehicle speed deviation. Adjust the clutch engagement state according to the target torque so that the vehicle travels at the target speed.

[0007] In this embodiment of the application, the target torque of the vehicle's clutch is determined based on a preset fuzzy adaptive PID controller, according to the vehicle speed deviation and the rate of change of the vehicle speed deviation, including: The vehicle speed deviation and the rate of change of vehicle speed deviation are mapped to the corresponding fuzzy domains to obtain the input fuzzy quantities. Based on preset fuzzy rules, fuzzy inference is performed on the input fuzzy quantity to obtain the adjusted fuzzy quantity; The fuzzy adjustment amount is defuzzified to obtain the parameter adjustment amount; The current control parameters of the preset fuzzy adaptive PID controller are updated based on the parameter adjustment amount; The target torque of the clutch is determined based on the updated PID control parameters.

[0008] In this embodiment of the application, when the vehicle's driving state simultaneously meets multiple preset activation conditions, it is determined that the vehicle is in micro-motion control mode. The multiple preset activation conditions include: The vehicle's gear position signal indicates whether it is in forward or reverse gear; The accelerator pedal opening of the vehicle is less than or equal to the preset opening threshold. The vehicle's actual speed is less than or equal to the preset speed threshold; The time interval between the current moment and the end time of the previous micro-motion control mode is greater than or equal to the preset time interval; The clutch oil circuit temperature difference of the vehicle is less than the preset activation temperature difference threshold. The clutch oil circuit temperature difference is the absolute value of the temperature difference between the input oil circuit and the output oil circuit of the clutch lubrication and cooling oil circuit.

[0009] In this embodiment of the application, the method further includes: Obtain the accelerator pedal opening of the vehicle; When the accelerator pedal opening is less than the preset accelerator pedal opening threshold and the actual vehicle speed is less than the preset vehicle speed threshold, the slope information of the vehicle's driving area and the vehicle's load information are obtained. Determine the slope holding torque based on slope and load information; When the holding torque on the slope is less than the preset clutch control torque, the slope information and load information are input into the pre-built engine target idle speed decision model to obtain the corresponding target idle speed. Control the engine to run at the target idle speed.

[0010] In this embodiment of the application, the method further includes: When the slope holding torque is greater than or equal to the preset clutch control torque, and less than or equal to the preset maximum slope holding torque, the vehicle is controlled to stop moving. When the slope holding torque is greater than the preset maximum slope holding torque, the vehicle is controlled to exit the micro-motion control mode; Among them, the preset clutch control torque is less than the preset maximum slope holding torque.

[0011] In this embodiment of the application, the method further includes the following steps in adjusting the engagement state of the clutch according to the target torque: Obtain the current engine speed and rate of decrease of the vehicle's engine; If the current speed is within the preset engine load warning range, or the speed drop rate is within the preset engine stall warning range, suspend the adjustment of the clutch engagement state until the current speed is greater than the upper limit of the preset engine load warning range and the speed drop rate is less than the lower limit of the preset engine stall warning range. When the current engine speed is lower than the lower limit of the preset engine load warning range, or the rate of speed decrease is higher than the upper limit of the preset engine stall warning range, the clutch is disengaged and the vehicle's transmission is shifted into neutral.

[0012] In this embodiment of the application, obtaining the target vehicle speed includes: Obtain the actual clutch pedal opening of the vehicle; Based on the preset mapping relationship between clutch pedal opening and vehicle speed, the target vehicle speed corresponding to the actual clutch pedal opening is determined.

[0013] A second aspect of this application provides a controller, comprising: The memory is configured to store instructions; The processor is configured to retrieve instructions from memory and, when executing the instructions, to implement the aforementioned method of micro-motion control of the vehicle.

[0014] A third aspect of this application provides a vehicle, including: the controller described above.

[0015] A fourth aspect of this application provides a vehicle control system, including: the controller described above, as well as a sensor detection unit, a transmission control unit, an engine control unit, and a proportional valve control unit.

[0016] The above technical solution, when the vehicle is in micro-motion control mode, acquires the actual vehicle speed and target vehicle speed in real time. The difference between the target speed and the actual speed is then defined as the speed deviation. Next, the rate of change of the speed deviation over time is determined. Subsequently, based on a preset fuzzy adaptive PID controller, the target torque of the vehicle's clutch is determined according to the speed deviation and its rate of change. The PID control parameters of the fuzzy adaptive PID controller are determined based on the fuzzy quantities corresponding to the speed deviation and its rate of change. Finally, the clutch engagement state is adjusted according to the target torque to ensure the vehicle travels at the target speed. This application achieves adaptive control for complex road conditions by dynamically adjusting the clutch target torque based on the speed deviation and its rate of change using a fuzzy adaptive PID controller, which is beneficial for improving the stability and accuracy of speed control.

[0017] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings: Figure 1 A flowchart illustrating a method for micro-motion control of a vehicle provided in an embodiment of this application; Figure 2 A fuzzy PID control principle diagram for a clutch target torque is provided in a specific embodiment of this application; Figure 3 This is a schematic diagram of a target idle speed decision model for an agricultural vehicle engine provided in a specific embodiment of this application; Figure 4 A structural block diagram of a vehicle micro-motion control system provided in a specific embodiment of this application; Figure 5 This is a structural block diagram of a controller provided in an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0022] Vehicle micro-motion control, also known as creep control, refers to the precise driving control of agricultural machinery and engineering vehicles at extremely low speeds during agricultural operations such as tilling, sowing, harvesting, and reversing into parking spaces. In these conditions, the driver does not press the accelerator or only slightly presses it, relying on the torque output from the engine idle speed to maintain a stable and precisely adjustable low-speed motion. Traditional low-speed control of agricultural machinery mainly relies on manual adjustment by the driver through the clutch pedal, which requires high driver skill and is difficult to maintain stable speed when road resistance changes, resulting in inconsistent control stability. Furthermore, existing automated control schemes are mostly fixed-parameter PID control designed for passenger cars, which is ill-suited to the complex and variable environment of agricultural operations. Therefore, this application provides a method for vehicle micro-motion control that effectively solves the technical problem of maintaining stable low-speed driving in agricultural vehicles during precise operations due to complex and variable road conditions. This method introduces an intelligent control system, transforming the traditional clutch operation, which relies on driver experience, into an automated and precise control process, significantly improving the vehicle's handling performance and operational quality under low-speed conditions. The steps involved in this method will be explained in detail below.

[0023] Figure 1 This is a flowchart illustrating a method for micro-motion control of a vehicle provided in an embodiment of this application. Figure 1 As shown in the figure, this application provides a method for micro-motion control of a vehicle, which may include the following steps.

[0024] Step S101: When the vehicle is in micro-motion control mode, the actual vehicle speed and target vehicle speed are acquired in real time.

[0025] In this embodiment, the micro-motion control mode is a special operating state designed for extremely low-speed driving, typically activated when the vehicle needs to perform delicate operations such as sowing, harvesting, or moving goods. Specifically, when the vehicle is in micro-motion control mode, the actual vehicle speed and target speed are acquired in real time. The actual vehicle speed can be continuously collected through onboard sensors, such as magnetoelectric wheel speed sensors, Hall effect wheel speed sensors, or GPS-based speed measurement modules; the target speed is the driving speed that the driver expects the vehicle to reach and maintain, and the target speed can be directly set by the driver through a knob, touchscreen, or physical button on the vehicle's center console.

[0026] Step S102: The difference between the target vehicle speed and the actual vehicle speed is determined as the vehicle speed deviation.

[0027] In this embodiment of the application, the vehicle speed deviation is a signed scalar whose magnitude reflects the degree to which the actual vehicle speed deviates from the target vehicle speed, and the positive or negative sign indicates the direction of deviation.

[0028] Step S103: Determine the rate of change of vehicle speed deviation based on the change of vehicle speed deviation over time.

[0029] In one example, the backward difference method can be used to determine the rate of change of vehicle speed deviation, which involves subtracting the vehicle speed deviation from the previous sampling time from the current sampling time's deviation, and then dividing by the sampling time interval. In another example, state observer theory, such as the Romberg observer, can be used to more accurately estimate state variables, including the rate of change of vehicle speed deviation, based on the system model. Vehicle speed deviation alone is insufficient to reflect the system's changing trend, while the rate of change of deviation can predict future deviation trends. A rate of change of vehicle speed deviation controller can adjust the control intensity in advance based on whether the deviation is increasing or decreasing. For example, when the deviation is positive and the rate of change is negative, it indicates that the actual vehicle speed is returning to the target value, and the controller can appropriately reduce the control action to avoid overshoot; conversely, if both the deviation and the rate of change are positive, it indicates that the vehicle speed is further deviating from the target, requiring a rapid increase in control action. This improves the system's adaptability.

[0030] Step S104: Based on the preset fuzzy adaptive PID controller, the target torque of the vehicle's clutch is determined according to the vehicle speed deviation and the rate of change of the vehicle speed deviation. The PID control parameters of the fuzzy adaptive PID controller are determined according to the fuzzy quantities corresponding to the vehicle speed deviation and the rate of change of the vehicle speed deviation.

[0031] It is understandable that traditional fixed-parameter PID controllers cannot adapt to the complex and variable characteristics of agricultural vehicle driving resistance. This application introduces a preset fuzzy adaptive PID controller. Fuzzy adaptive control can adjust controller parameters online in real time, ensuring the system maintains excellent control performance. Specifically, during micro-motion control, vehicle speed deviation and its rate of change serve as input signals to the fuzzy adaptive PID controller. By calculating the vehicle speed deviation *e* and its rate of change *ec*, fuzzy inference is performed using fuzzy rules, and the fuzzy matrix table is consulted to adjust the parameters, ultimately obtaining the corrected parameter values ​​for the PID controller. This completes the online self-calibration of the PID controller parameters, and finally, the fuzzy adaptive PID controller outputs the target torque of the clutch.

[0032] In this way, the controller parameters can be self-tuned and self-adapted, so that the control system can automatically adjust to the optimal state regardless of whether the vehicle is on a hard road, soft mud or under a slope load, thereby achieving fast, smooth and overshoot-free speed tracking, and solving the problem of poor robustness of fixed parameter controllers.

[0033] Step S105: Adjust the clutch engagement state according to the target torque so that the vehicle travels at the target speed.

[0034] In one example, the controller converts the target torque value into a corresponding target hydraulic pressure based on the clutch torque model, and then outputs a corresponding current signal to drive the electro-hydraulic proportional valve. The proportional valve adjusts the flow rate and pressure of the hydraulic fluid entering the clutch hydraulic cylinder, thereby controlling the clamping force of the clutch pressure plate and achieving stepless adjustment of the engagement degree. In another example, for an electronically controlled dry clutch, the position of the clutch fork can be directly controlled by a motor or electromagnetic actuator. During the adjustment of the clutch engagement state, this application can also integrate safety protection logic, such as temporarily freezing or reducing torque output when a sharp drop in engine speed is detected that poses a risk of stalling.

[0035] The above technical solution, when the vehicle is in micro-motion control mode, acquires the actual vehicle speed and target vehicle speed in real time. The difference between the target speed and the actual speed is then defined as the speed deviation. Next, the rate of change of the speed deviation over time is determined. Subsequently, based on a preset fuzzy adaptive PID controller, the target torque of the vehicle's clutch is determined according to the speed deviation and its rate of change. The PID control parameters of the fuzzy adaptive PID controller are determined based on the fuzzy quantities corresponding to the speed deviation and its rate of change. Finally, the clutch engagement state is adjusted according to the target torque to ensure the vehicle travels at the target speed. This application achieves adaptive control for complex road conditions by dynamically adjusting the clutch target torque based on the speed deviation and its rate of change using a fuzzy adaptive PID controller, which is beneficial for improving the stability and accuracy of speed control.

[0036] In this embodiment of the application, when the vehicle's driving state simultaneously meets multiple preset activation conditions, it is determined that the vehicle is in micro-motion control mode. The multiple preset activation conditions may include: The vehicle's gear position signal indicates whether it is in forward or reverse gear; The accelerator pedal opening of the vehicle is less than or equal to the preset opening threshold. The vehicle's actual speed is less than or equal to the preset speed threshold; The time interval between the current moment and the end time of the previous micro-motion control mode is greater than or equal to the preset time interval; The clutch oil circuit temperature difference of the vehicle is less than the preset activation temperature difference threshold. The clutch oil circuit temperature difference is the absolute value of the temperature difference between the input oil circuit and the output oil circuit of the clutch lubrication and cooling oil circuit.

[0037] In this embodiment of the application, in order to ensure that the micro-motion control mode is activated only under safe and appropriate operating conditions, and to prevent the system from being accidentally triggered or from being damaged by unsuitable conditions, multiple preset activation conditions that must be met simultaneously are set.

[0038] First, the vehicle's gear position signal must be in either forward or reverse. This condition limits the micro-motion control mode to only when the vehicle has a clear intention to move, excluding states such as neutral and park where power engagement is unnecessary or prohibited. This ensures that the activation of the micro-motion control mode is consistent with the driver's basic operational intentions. Figure 1 This is to prevent accidental activation in the wrong gear.

[0039] Second, the accelerator pedal opening must be less than or equal to a preset threshold. This condition is used to determine that the driver currently has no intention of actively accelerating. The accelerator pedal opening can be monitored by a pedal position sensor. When the opening is below a set threshold close to zero, it indicates that the driver expects the vehicle to operate at idle speed or very low power, which is suitable for initiating automatic control. This ensures that the intervention of the automated system does not interfere with the driver's main control operation, maintaining a clear boundary for human-machine collaboration.

[0040] Third, the actual vehicle speed must be less than or equal to a preset speed threshold. This condition defines the upper limit of the low-speed range applicable to the micro-motion control mode. The actual vehicle speed can be obtained through wheel speed sensors, etc. Only when it is lower than the preset speed threshold is the vehicle considered to be in a low-speed state requiring precise control, thereby preventing the system from operating at unsuitable medium to high speeds and avoiding control logic conflicts.

[0041] Fourth, the time interval between the current moment and the end of the previous micro-motion mode must be greater than or equal to a preset time interval. This condition is based on the clutch thermal protection design and aims to provide the clutch with the necessary heat dissipation recovery period. The preset time interval ensures that after the end of the previous creep control mode, the clutch has sufficient time for the cooling system to reduce its temperature to a safe level, such as close to the transmission oil temperature, thereby effectively preventing the risk of overheating due to continuous operation.

[0042] Fifth, the clutch oil circuit temperature difference must be less than a preset activation temperature difference threshold. This clutch oil circuit temperature difference is the absolute difference between the inlet and outlet temperatures of the lubrication and cooling oil circuit, reflecting the current heat generation intensity of the clutch. The clutch oil circuit temperature difference can be monitored in real time by placing temperature sensors at key points in the oil circuit. Only when the clutch oil circuit temperature difference is lower than the preset activation temperature difference threshold does it indicate that the clutch has been sufficiently cooled from the previous operation and can be safely started, enabling real-time monitoring of the clutch's health status. The preset activation temperature difference threshold can be determined through bench testing and road calibration.

[0043] As described above, the embodiments of this application jointly determine the driving intention, power demand, vehicle speed status, historical load and real-time thermal status from five key dimensions, which together constitute the activation mechanism of the micro-motion control mode. This minimizes the possibility of false activation and abuse of the system, while providing automation convenience and prioritizing the safety and durability of the transmission system, ensuring that the function is reliably activated only when truly needed and under permissible conditions.

[0044] After the transmission enters the micro-motion control state, the clutch will continuously operate in a slipping friction state, which will cause the clutch temperature to gradually rise. To address this, this embodiment employs a real-time monitoring mechanism, continuously collecting the temperatures of the clutch input and output oil circuits in the lubrication and cooling oil circuit using a temperature sensor, and calculating the temperature difference between them; simultaneously, a timer accumulates and records the duration of the micro-motion control.

[0045] The system has preset micro-motion time thresholds and clutch safety temperature difference thresholds. After the micro-motion control mode is activated, the timer starts accumulating the micro-motion time, while the temperature sensor monitors and calculates the clutch oil temperature difference in real time. If the micro-motion time is less than the micro-motion time threshold and the clutch oil temperature difference is less than the safety temperature difference threshold, the vehicle will maintain the micro-motion control process. Once the micro-motion time reaches or exceeds the time threshold, or the clutch oil temperature difference reaches or exceeds the safety temperature difference threshold, the controller will immediately control the clutch to disengage, the transmission to shift into neutral, and activate the cooling system to force-cool the clutch. At the same time, another timer starts recording the cooling time.

[0046] During the micro-motion control preparation stage, after the controller detects that the micro-motion control mode is activated, it will control the proportional valve to make the clutch pressure reach the preset pressure threshold P1, thereby smoothly entering the micro-motion control stage.

[0047] In this way, by monitoring and providing real-time feedback on the micro-motion time and clutch oil circuit temperature difference during the micro-motion control process, a safe closed-loop management of the clutch's operating status is achieved. This ensures both the continuity and stability of micro-motion control and effectively prevents clutch damage due to prolonged slippage or excessive temperature, thereby improving the system's reliability and service life.

[0048] In this embodiment of the application, obtaining the target vehicle speed may include: Obtain the actual clutch pedal opening of the vehicle; Based on the preset mapping relationship between clutch pedal opening and vehicle speed, the target vehicle speed corresponding to the actual clutch pedal opening is determined.

[0049] In this embodiment of the application, in order to accurately convert the driver's intuitive and continuous control needs for vehicle speed into quantitative commands that the control system can execute, the target vehicle speed can be directly mapped through the clutch pedal opening.

[0050] Specifically, the actual clutch pedal opening of the vehicle is first obtained. This actual opening is acquired using a high-precision position sensor mounted on the pedal shaft or linkage; common types include potentiometers or non-contact Hall effect sensors. The sensor converts the mechanical displacement of the pedal into a linear electrical signal, which undergoes hardware and software filtering to eliminate vibrations and noise interference, thus obtaining a stable and accurate opening value. Next, based on a preset mapping relationship between clutch pedal opening and vehicle speed, the corresponding target vehicle speed is determined. It can be understood that a larger clutch pedal opening results in a higher desired vehicle speed.

[0051] The preset mapping relationship between clutch pedal opening and vehicle speed can be represented by a one-dimensional interpolation table. When the vehicle makes slight movements, the driver's desired speed is determined based on the interpolated clutch pedal opening. and Corresponding to the minimum and maximum clutch pedal opening, The most harmonious These are the pre-set maximum and minimum desired vehicle speeds. In one example, the clutch pedal opening and vehicle speed have a linear relationship, and the linear interpolation relationship is: ; It is understandable that, in practical applications, a nonlinear interpolation relationship can be defined based on the difficulty the driver has in controlling the clutch pedal opening.

[0052] Furthermore, in this embodiment, the clutch pedal detection switch can detect the status of the clutch pedal position sensor in real time. When the clutch pedal position sensor data is abnormal, the clutch pedal detection switch sends a signal to the transmission controller, which then controls the clutch to disengage and the transmission to shift into neutral.

[0053] In this embodiment of the application, determining the target torque of the vehicle's clutch based on a preset fuzzy adaptive PID controller, according to the vehicle speed deviation and the rate of change of the vehicle speed deviation, may include: The vehicle speed deviation and the rate of change of vehicle speed deviation are mapped to the corresponding fuzzy domains to obtain the input fuzzy quantities. Based on preset fuzzy rules, fuzzy inference is performed on the input fuzzy quantity to obtain the adjusted fuzzy quantity; The fuzzy adjustment amount is defuzzified to obtain the parameter adjustment amount; The current control parameters of the preset fuzzy adaptive PID controller are updated based on the parameter adjustment amount; The target torque of the clutch is determined based on the updated PID control parameters.

[0054] It is understandable that, in order to enable the controller to self-tune parameters online according to complex and ever-changing driving conditions and obtain superior control performance compared to fixed-parameter PID, this application embodiment determines the target torque of the vehicle's clutch based on a preset fuzzy adaptive PID controller. By simulating the adjustment thinking of human experts, the controller possesses self-learning and adaptive capabilities, thereby outputting a reasonable target clutch torque under various road resistances, overcoming the inherent limitations of traditional PID in dealing with the nonlinear and time-varying control problems of agricultural vehicles.

[0055] Figure 2 This is a schematic diagram illustrating the fuzzy PID control principle for a clutch target torque, provided as a specific embodiment of this application. Specifically, in conjunction with... Figure 2 As shown, the process of controlling vehicle speed using a fuzzy adaptive PID controller is as follows: The deviation between the driver's expected target speed and the actual vehicle speed. and the rate of change of vehicle speed deviation As input, the vehicle speed deviation and the rate of change of vehicle speed deviation The range of variation is defined as the universe of discourse on the fuzzy set. , The quantification factors are respectively and Fuzzy subsets are defined as The elements in the subset represent negative large, negative medium, negative small, zero, positive small, positive medium, and positive large, respectively. Assuming that e, ec, and the PID control parameters kp, ki, and kd all follow a normal distribution, the membership degrees of each fuzzy subset are obtained. Based on the membership degree assignment table of each fuzzy subset and the fuzzy control model of each parameter, fuzzy inference using the Mamdani method is applied, and the centroid method is used for defuzzification to obtain the values ​​of the PID parameter correction parameters, which are then substituted into the following formula for calculation: ; in, , and These are the PID parameters from the previous time step. k(k) represents the adjustment range of the PID parameters after fuzzy inference at the previous time step, and k(k+1) represents the adjusted PID parameters at the next time step.

[0056] The fuzzy rule table is as follows: Table 1 Fuzzy rule table

[0057] Table 2 Fuzzy rule table

[0058] Table 3 Fuzzy rule table

[0059] Mamdani fuzzy reasoning: Fuzzy implication relations are obtained through the Cartesian product of fuzzy sets, and the fuzzy relation formula is: ; Centroid-based defuzzification: The membership function curve of the output fuzzy subset and the coordinate axis region of the fuzzy universe are treated as a plane, and the x-coordinate of the centroid of this plane is taken as the output result. The mathematical expression is: ; In the formula, To output the corresponding values ​​of the membership function of the fuzzy subset in the fuzzy universe of discourse, for The corresponding membership function value, This is the output result. After obtaining the output result, a scaling transformation is performed to convert the output result into the actual values ​​of the PID parameter correction parameters, i.e., from the fuzzy domain. Output range of actual control quantity of conversion value A linear transformation is used: ; Furthermore, based on the clutch target torque signal output by the fuzzy adaptive PID controller, the clutch target torque signal is converted into a clutch control oil pressure signal through the clutch transmission torque model. The clutch oil pressure is changed by controlling the current signal of the electro-hydraulic proportional valve, thereby achieving the tracking of the vehicle target speed.

[0060] The method for calculating clutch oil pressure signals is as follows: ; Where T is the target torque of the clutch. The coefficient of dynamic friction of the clutch. Where A is the effective friction surface radius, A is the clutch piston area, and Z is the number of clutch friction pairs.

[0061] In this embodiment of the application, the method may further include: Obtain the accelerator pedal opening of the vehicle; When the accelerator pedal opening is less than the preset accelerator pedal opening threshold and the actual vehicle speed is less than the preset vehicle speed threshold, the slope information of the vehicle's driving area and the vehicle's load information are obtained. Determine the slope holding torque based on slope and load information; When the holding torque on the slope is less than the preset clutch control torque, the slope information and load information are input into the pre-built engine target idle speed decision model to obtain the corresponding target idle speed. Control the engine to run at the target idle speed.

[0062] In this embodiment of the application, in order to fundamentally prevent the vehicle from stalling due to insufficient engine power on slopes and under heavy load conditions, this embodiment of the application adds an engine idle speed adaptive feedforward control based on operating condition perception.

[0063] Specifically, the first step is to acquire the accelerator pedal opening, which is monitored in real time by sensors. To ensure the absolute priority of driver commands during human-machine collaboration and to prevent automated control from interfering with manual operation, the controller compares the accelerator pedal opening with a preset accelerator pedal opening threshold to determine if the driver currently intends to actively accelerate. When the accelerator pedal opening... Preset throttle opening threshold And actual vehicle speed Preset vehicle speed threshold When the vehicle is in a low-speed, low-throttle condition, the engine idle speed control is activated. The slope information is obtained through the tilt sensor or GPS elevation data, and the vehicle load information is obtained through the suspension pressure sensor or engine torque back-calculation model.

[0064] Next, by combining information on slope, load, wheel radius, and rolling resistance coefficient, the slope resistance torque and rolling resistance torque are determined. The sum of these two torques is then determined as the slope holding torque. The slope holding torque is the minimum driving torque required to overcome the gravitational component of the downward force and rolling resistance. The greater the slope and the heavier the load, the greater the vehicle resistance and the higher the required slope holding torque. The larger.

[0065] Furthermore, comparing the torque held on inclines. and preset clutch control torque The preset clutch control torque is the maximum torque that the gearbox can control the clutch output to achieve micro-motion control. If The slope and load information are then input into the engine target idle speed decision model to obtain the corresponding target idle speed. This engine target idle speed decision model can be a pre-calibrated mapping relationship between slope, load, and idle speed, and its output is the optimal idle speed matching the current resistance. In one specific embodiment, Figure 3 This is a schematic diagram of a target idle speed decision model for an agricultural vehicle's engine, provided in a specific embodiment of this application. For agricultural vehicles, the vehicle's gradient... Load and idle speed The correspondence is as follows Figure 3 As shown, the engine's maximum idle speed Engine minimum idle speed The maximum road gradient is determined by the actual performance of the engine used in the vehicle. The load range of the vehicle with agricultural implements and the load range of the vehicle without agricultural implements can be calibrated through testing.

[0066] Finally, the engine is controlled to operate at the target idle speed. Commands are sent to the engine control unit via the vehicle network to adjust the fuel supply and intake air, so that the engine speed smoothly tracks the target idle speed. This ensures that the engine can provide sufficient torque and maintain a stable idle speed when the load increases, allowing the vehicle to maintain a slight fluctuation at the target speed on the road.

[0067] In this embodiment of the application, the method may further include: When the slope holding torque is greater than or equal to the preset clutch control torque, and less than or equal to the preset maximum slope holding torque, the vehicle is controlled to stop moving. When the slope holding torque is greater than the preset maximum slope holding torque, the vehicle is controlled to exit the micro-motion control mode; Among them, the preset clutch control torque is less than the preset maximum slope holding torque.

[0068] In this embodiment of the application, to establish a complete safety response system for hill-start assist, this application further defines a graded safety control strategy based on capability boundary comparison, building upon engine idle speed adjustment. It is understood that when external resistance demands exceed certain controllable capabilities of the system, simply increasing power is insufficient to guarantee safety. In such cases, more conservative intervention measures are required, including active braking or complete disengagement from automation mode, thereby ensuring that the driver and vehicle remain in a safe and controllable state under any operating condition.

[0069] In one example, maintaining torque on a slope. Preset clutch control torque And maintain torque on slopes Preset maximum slope holding torque At this time, the vehicle is controlled to stop moving, keeping it stationary on the slope. The preset maximum slope-holding torque is used. The maximum slope-holding torque is preset to ensure the vehicle maintains its maximum torque to prevent slippage on an incline. Preset clutch control torque Both can be calibrated experimentally to obtain specific values. When the required torque falls between these two values, it indicates that the clutch can no longer meet the continuous driving demand, but the vehicle is still capable of safely parking. At this time, the system will control the clutch to disengage, apply the brakes, and prompt the driver, so that the driver can actively bring the vehicle into a safe static holding state, avoiding the risk of clutch overload damage and vehicle rollback.

[0070] In another example, in At this point, the vehicle exits the micro-motion control mode. The resistance demand has exceeded the vehicle's holding capacity limit, posing a risk of slippage. The system will execute the highest level of safety measures, immediately terminating automatic control, disengaging the clutch, applying full braking, and issuing a loud alarm, ultimately returning complete control to the driver. Thus, by thoroughly isolating and warning of uncontrollable risks, accidents can be prevented to the greatest extent possible.

[0071] In this embodiment of the application, the method may further include the following steps in adjusting the engagement state of the clutch according to the target torque: Obtain the current engine speed and rate of decrease of the vehicle's engine; If the current speed is within the preset engine load warning range, or the speed drop rate is within the preset engine stall warning range, suspend the adjustment of the clutch engagement state until the current speed is greater than the upper limit of the preset engine load warning range and the speed drop rate is less than the lower limit of the preset engine stall warning range. When the current engine speed is lower than the lower limit of the preset engine load warning range, or the rate of speed decrease is higher than the upper limit of the preset engine stall warning range, the clutch is disengaged and the vehicle's transmission is shifted into neutral.

[0072] It is understandable that even if the vehicle idle speed is pre-adjusted, the vehicle may still encounter unexpected resistance during actual driving. The real-time operating condition of the engine is the most direct risk indicator. In order to implement real-time and active protection of the engine during the vehicle's micro-movement process and prevent it from stalling due to a sudden increase in instantaneous load, this application embodiment adds a graded protection control logic based on engine dynamic status monitoring.

[0073] Specifically, the current engine speed and its rate of decrease are first acquired. The current engine speed is provided by the crankshaft position sensor; the rate of decrease can be calculated using speed differential. Then, the current engine speed is compared with a preset engine load warning range, and the rate of decrease is compared with a preset engine stall warning range. The load warning range is a speed band slightly below normal idle speed, with its upper limit being the highest engine speed threshold and its lower limit being the lowest engine speed threshold. The stall warning range is a range reflecting an abnormally rapid decrease in speed, with its upper limit being the highest engine speed decrease rate threshold and its lower limit being the lowest engine speed decrease rate threshold.

[0074] In one example, when the current engine speed is within the load warning range or the rate of speed decrease is within the stall warning range, clutch adjustment is paused, i.e., the clutch torque command is frozen to prevent further load increase, allowing the engine room to recover on its own. Clutch adjustment resumes only when the current engine speed exceeds the upper limit of the preset engine load warning range and the rate of speed decrease is less than the lower limit of the preset engine stall warning range. This allows for gentle, conservative intervention at the initial stage of risk, preventing deterioration of operating conditions and avoiding engine stalling in most cases, thus ensuring power continuity.

[0075] In another example, when the current engine speed is below the lower limit of the load warning range or the rate of speed decrease is above the upper limit of the stall warning range, the clutch is disengaged and the transmission is shifted into neutral. At this point, the engine is on the verge of forced shutdown, requiring the highest level of protection. Clutch disengagement instantly removes all load, and shifting into neutral completely cuts off the power transmission path. This allows for the most decisive emergency braking procedure in critical situations, maximizing engine protection from the stall impact and ensuring the vehicle remains in a basically safe state.

[0076] This application also provides a vehicle control system, including: the controller described in the above embodiments, as well as a sensor detection unit, a transmission control unit, an engine control unit, and a proportional valve control unit.

[0077] Figure 4 This is a structural block diagram of a vehicle micro-motion control system provided in a specific embodiment of this application. Figure 4 As shown in a specific embodiment of this application, the vehicle micro-motion control system may include: The sensor detection unit includes a throttle position sensor, vehicle speed sensor, clutch pedal position sensor, clutch pedal detection switch, engine output speed sensor, clutch pressure sensor, slope and load sensor, clutch input oil circuit temperature sensor, clutch output oil circuit temperature sensor, etc., which collect signals such as engine speed, actual vehicle speed, throttle opening, clutch opening, clutch pressure, transmission input speed and transmission output speed in real time.

[0078] The transmission control unit is used to acquire clutch pedal, accelerator signals and system information collected by various sensors to make decisions on the vehicle's micro-motion control process; it acquires the clutch target torque signal based on the target vehicle speed and the actual vehicle speed, converts it into an oil pressure control signal and sends it to the proportional valve control unit to achieve the tracking of the desired vehicle speed.

[0079] The engine control unit, based on the target idle speed signal sent by the transmission control unit, achieves a stable engine speed output.

[0080] The proportional valve control unit is used to convert the required oil pressure control signal into a proportional valve current signal, control the output of the electro-hydraulic proportional control system to engage the clutch oil pressure, and achieve the tracking of the clutch target torque.

[0081] Figure 5 This is a structural block diagram of a controller provided in an embodiment of this application. Figure 5 As shown in the figure, this application provides a controller that may include: Memory 510 is configured to store instructions; The processor 520 is configured to retrieve instructions from the memory 510 and, when executing the instructions, to implement the aforementioned method of vehicle micro-motion control.

[0082] This application also provides a vehicle, including the controller described in the above embodiments.

[0083] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0084] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0085] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0086] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0087] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0088] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0089] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0090] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0091] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for micro-motion control of a vehicle, characterized in that, The method includes: When the vehicle is in micro-motion control mode, the actual vehicle speed and target vehicle speed are acquired in real time. The difference between the target vehicle speed and the actual vehicle speed is defined as the vehicle speed deviation; The rate of change of vehicle speed deviation is determined based on the change of vehicle speed deviation over time. Based on a preset fuzzy adaptive PID controller, the target torque of the vehicle's clutch is determined according to the vehicle speed deviation and the rate of change of the vehicle speed deviation, wherein the PID control parameters of the fuzzy adaptive PID controller are determined according to the fuzzy quantities corresponding to the vehicle speed deviation and the rate of change of the vehicle speed deviation. Adjust the engagement state of the clutch according to the target torque so that the vehicle travels at the target speed.

2. The method according to claim 1, characterized in that, The method of determining the target torque of the vehicle's clutch based on a preset fuzzy adaptive PID controller, according to the vehicle speed deviation and the rate of change of the vehicle speed deviation, includes: The vehicle speed deviation and the rate of change of the vehicle speed deviation are respectively mapped to the corresponding fuzzy domain to obtain the input fuzzy quantity; Based on preset fuzzy rules, fuzzy inference is performed on the input fuzzy quantity to obtain the adjusted fuzzy quantity; The adjustment fuzzy amount is defuzzified to obtain the parameter adjustment amount; The current control parameters of the preset fuzzy adaptive PID controller are updated based on the parameter adjustment amount; The target torque of the clutch is determined based on the updated PID control parameters.

3. The method according to claim 1, characterized in that, When the vehicle's driving state simultaneously meets multiple preset activation conditions, the vehicle is determined to be in micro-motion control mode, wherein the multiple preset activation conditions include: The vehicle's gear position signal is in forward or reverse gear; The accelerator pedal opening of the vehicle is less than or equal to a preset opening threshold. The actual speed of the vehicle is less than or equal to a preset speed threshold. The time interval between the current moment and the end time of the previous micro-motion control mode is greater than or equal to the preset time interval; The clutch oil circuit temperature difference of the vehicle is less than the preset activation temperature difference threshold. The clutch oil circuit temperature difference is the absolute value of the temperature difference between the input oil circuit and the output oil circuit of the clutch lubrication and cooling oil circuit.

4. The method according to claim 1, characterized in that, The method further includes: Obtain the accelerator pedal opening of the vehicle; When the accelerator pedal opening is less than a preset accelerator pedal opening threshold and the actual vehicle speed is less than a preset vehicle speed threshold, the slope information of the vehicle's driving area and the vehicle's load information are obtained. The slope holding torque is determined based on the slope information and the load information; When the slope holding torque is less than the preset clutch control torque, the slope information and the load information are input into the pre-built engine target idle speed decision model to obtain the corresponding target idle speed. Control the engine to operate at the target idle speed.

5. The method according to claim 4, characterized in that, The method further includes: When the slope holding torque is greater than or equal to the preset clutch control torque, and less than or equal to the preset maximum slope holding torque, the vehicle is controlled to stop moving. If the slope holding torque is greater than the preset maximum slope holding torque, control the vehicle to exit the micro-motion control mode; Wherein, the preset clutch control torque is less than the preset maximum slope holding torque.

6. The method according to claim 1, characterized in that, In adjusting the engagement state of the clutch according to the target torque, the method further includes: Obtain the current engine speed and the rate of decrease of the engine speed of the vehicle; If the current speed is within the preset engine load warning range, or the speed drop rate is within the preset engine stall warning range, the adjustment of the clutch engagement state is suspended until the current speed is greater than the upper limit of the preset engine load warning range and the speed drop rate is less than the lower limit of the preset engine stall warning range. When the current engine speed is less than the lower limit of the preset engine load warning range, or when the engine speed decrease rate is higher than the upper limit of the preset engine stall warning range, the clutch is disengaged and the vehicle's transmission is shifted into neutral.

7. The method according to claim 1, characterized in that, Obtaining the target speed of the vehicle includes: Obtain the actual clutch pedal opening of the vehicle; Based on the preset mapping relationship between clutch pedal opening and vehicle speed, the target vehicle speed corresponding to the actual clutch pedal opening is determined.

8. A controller, characterized in that, include: The memory is configured to store instructions; The processor is configured to retrieve instructions from memory and, when executing the instructions, to implement the method of micro-motion control of a vehicle according to any one of claims 1 to 7.

9. A vehicle control system, characterized in that, include: The controller as described in claim 8, as well as the sensor detection unit, the transmission control unit, the engine control unit, and the proportional valve control unit.

10. A vehicle, characterized in that, include: The controller according to claim 8 or the vehicle control system according to claim 9.

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