Vehicle torque control method and electronic device

Abstract

The present application provides a torque control method and electronic device for a vehicle, which adjusts the default vehicle speed in creep mode according to the vehicle operating parameters, obtains a target vehicle speed that is more suitable for the current driving scene, and ensures the stability of the creep process. The initial control torque before compensation is determined according to the speed difference between the target vehicle speed and the current vehicle speed, and then the slope compensation torque corresponding to the current vehicle speed and the current detected slope is determined according to the target relationship data corresponding to the current gear position. When the vehicle speed, gear position and slope are different, different slope compensation torques will be obtained, realizing personalized torque compensation for various scenes in creep mode, ensuring the normal creep driving in different driving scenes, and controlling the drive device to output torque according to the creep request torque after torque compensation, avoiding the risk of slipping due to insufficient power.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a vehicle torque control method and electronic equipment. Background Art

[0002] Vehicles are equipped with Hill-Hold-Control (HHC) and Hill Descent Control (HDC) to alleviate the problem of rolling on sloping roads. However, not all vehicles are equipped with Hill-Hold-Control and Hill Descent Control, resulting in the risk of rolling when users drive on sloping roads. Summary of the invention

[0003] In view of this, the purpose of the present application is to propose a vehicle torque control method and electronic equipment, which can avoid the risk of rolling on a sloped road by performing torque compensation in a creep mode.

[0004] Based on the above purpose, a first aspect of the present application provides a vehicle torque control method, comprising:

[0005] In response to the creep mode being activated and the current vehicle speed satisfying the creep control condition, the creep mode is entered, and a target vehicle speed is determined according to the vehicle operating parameters and a preset default vehicle speed;

[0006] determining an initial control torque according to a vehicle speed difference between the target vehicle speed and the current vehicle speed;

[0007] determining a slope compensation torque corresponding to the current vehicle speed and the current detected slope according to the target relationship data corresponding to the current gear position;

[0008] The initial control torque is torque compensated according to the slope compensation torque to obtain a creep request torque, and the drive device is controlled to output torque according to the creep request torque.

[0009] Optionally, determining the target vehicle speed according to the vehicle operating parameters and a preset default vehicle speed includes:

[0010] Determine a slope correction parameter according to the current detected slope in the vehicle operation parameter, and determine a slope-corrected vehicle speed according to the slope correction parameter and the default vehicle speed;

[0011] Determining a steering angle correction parameter according to a steering wheel angle in the vehicle operation parameter, and determining a steering angle correction vehicle speed according to the steering angle correction parameter and the default vehicle speed;

[0012] Determine a pressure correction parameter according to a master cylinder pressure value of a brake master cylinder in the vehicle operation parameter, and determine a pressure-corrected vehicle speed according to the pressure correction parameter and the default vehicle speed;

[0013] The minimum value among the slope-corrected vehicle speed, the corner-corrected vehicle speed, and the pressure-corrected vehicle speed is used as the target vehicle speed.

[0014] Optionally, determining the initial control torque according to the vehicle speed difference between the target vehicle speed and the current vehicle speed includes:

[0015] Determine the product of the vehicle speed difference and a preset proportional gain coefficient as the proportional control torque;

[0016] Performing an integration operation on the vehicle speed difference to obtain an integral value, and determining the product of the integral value and a preset integral gain coefficient as the integral control torque;

[0017] The sum of the proportional control torque and the integral control torque is determined as the initial control torque.

[0018] Optionally, determining the slope compensation torque corresponding to the current vehicle speed and the current detected slope according to the target relationship data corresponding to the current gear position includes:

[0019] In response to the current gear being a forward gear, determining preset forward gear compensation relationship data as the target relationship data;

[0020] In response to the current gear being a reverse gear, determining preset reverse gear compensation relationship data as the target relationship data;

[0021] determining a driving state according to a slope value of the current detected slope;

[0022] determining torque-speed relationship data according to the driving state and the target relationship data;

[0023] The search torque corresponding to the current vehicle speed in the torque-speed relationship data is determined as the slope compensation torque.

[0024] Optionally, determining the torque-speed relationship data according to the driving state and the target relationship data includes:

[0025] In response to the target relationship data being the forward gear compensation relationship data and the driving state being an uphill state, determining the positive slope region data in the forward gear compensation relationship data as the torque-speed relationship data;

[0026] In response to the target relationship data being reverse gear compensation relationship data and the driving state being an uphill state, determining the positive slope region data in the reverse gear compensation relationship data as the torque-speed relationship data;

[0027] In response to the target relationship data being the forward gear compensation relationship data and the driving state being a downhill state, determining the negative slope region data in the forward gear compensation relationship data as the torque-speed relationship data;

[0028] In response to the target relationship data being the reverse gear compensation relationship data and the driving state being a downhill state, negative gradient region data in the reverse gear compensation relationship data is determined as the torque-speed relationship data.

[0029] Optionally, determining whether the current vehicle speed satisfies the creep control condition includes:

[0030] determining a vehicle speed interval corresponding to the creep control condition;

[0031] In response to the actual speed being less than or equal to the upper boundary vehicle speed of the vehicle speed interval, determining that the current vehicle speed satisfies the creep control condition;

[0032] In response to the actual speed being greater than the upper boundary vehicle speed of the vehicle speed interval, it is determined that the current vehicle speed does not satisfy the creep control condition.

[0033] Optionally, after determining that the current vehicle speed does not satisfy the creep control condition, the method further includes:

[0034] Determine the coasting recovery torque;

[0035] determining an initial slope request compensation torque according to the coasting recovery torque and the current vehicle speed;

[0036] determining a target correction coefficient relationship according to the current gear position, and determining a request compensation coefficient corresponding to the current detected slope and the current vehicle speed according to the target correction coefficient relationship;

[0037] determining a product of the initial slope request compensation torque and the request compensation coefficient as a slope request compensation torque, and determining a sum of the coasting recovery torque and the slope request compensation torque as a requested total torque;

[0038] The vehicle is controlled to decelerate according to the requested total torque until it decelerates to the upper boundary vehicle speed, and it is determined that the creep control condition is satisfied.

[0039] Optionally, the vehicle torque control method further includes:

[0040] Real-time monitoring of the accelerator pedal's accelerator pedal stroke, the brake pedal's brake pedal stroke and the real-time vehicle speed;

[0041] determining an accelerator request torque corresponding to the accelerator pedal stroke and a brake master cylinder pressure value corresponding to the brake pedal stroke;

[0042] In response to the real-time vehicle speed being greater than or equal to a preset exit speed, and the first duration of the real-time vehicle speed being greater than or equal to the exit speed being greater than or equal to a preset first delay threshold, exiting the creep mode; wherein the exit speed is greater than or equal to an upper boundary speed; or,

[0043] In response to the throttle request torque being greater than or equal to the creep request torque, and the second duration for which the throttle request torque is greater than or equal to the creep request torque being greater than or equal to a preset second delay threshold, exiting the creep mode; or,

[0044] In response to the master cylinder pressure value being greater than or equal to a preset pressure threshold, and a third duration of the master cylinder pressure value being greater than or equal to the preset pressure threshold being greater than or equal to a preset third delay threshold, the creep mode is exited.

[0045] The second aspect of the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method provided in the first aspect of the present application is implemented.

[0046] The third aspect of the present application provides a vehicle, comprising the electronic device provided in the third aspect of the present application.

[0047] As can be seen from the above, the torque control method and electronic device of the vehicle provided by the present application enter the creeping mode when the creeping mode is activated and the current vehicle speed meets the creeping control conditions, determine the target vehicle speed according to the vehicle operating parameters and the preset default vehicle speed; determine the initial control torque according to the vehicle speed difference between the target vehicle speed and the current vehicle speed; determine the slope compensation torque corresponding to the current vehicle speed and the current detected slope according to the target relationship data corresponding to the current gear; perform torque compensation on the initial control torque according to the slope compensation torque to obtain the creeping request torque, and control the drive device to output torque according to the creeping request torque. The default vehicle speed in the creeping mode is adjusted according to the vehicle operating parameters to obtain a target vehicle speed that is more suitable for the current driving scene to ensure the stability of the creeping process. The initial control torque before compensation is determined based on the speed difference between the target vehicle speed and the current vehicle speed. Then, the slope compensation torque corresponding to the current vehicle speed and the current detected slope is determined based on the target relationship data corresponding to the current gear. When the vehicle speed, gear and slope are different, different slope compensation torques will be obtained to achieve personalized torque compensation for various scenarios in the creep mode, ensure the normal creep driving in different driving scenarios, and control the torque output of the drive device based on the creep request torque after torque compensation to avoid the risk of slipping due to insufficient power. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 This is a flow chart of a torque control method for a vehicle according to an embodiment of the present application;

[0050] Figure 2 A flow chart for determining a target vehicle speed for an embodiment of the present application;

[0051] Figure 3 A flow chart for determining the initial control torque for an embodiment of the present application;

[0052] Figure 4 A flow chart for determining the slope compensation torque for an embodiment of the present application;

[0053] Figure 5 This is a flow chart of an embodiment of the present application for determining whether the current vehicle speed satisfies the creep control condition;

[0054] Figure 6 This is a flow chart of deceleration according to the slope in an embodiment of the present application;

[0055] Figure 7 A flowchart of exiting crawling for an embodiment of the present application;

[0056] Figure 8 It is a structural schematic diagram of a torque control device of a vehicle according to an embodiment of the present application;

[0057] Fig. 9 It is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0059] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0060] It should be understood herein that any number of elements in the drawings is for illustration rather than limitation, and any naming is only for distinction rather than having any limiting meaning.

[0061] Based on the description of the above background technology, the related technology also has the following situations:

[0062] In the related technology, the motor system of new energy vehicles has two states: driving state and recovery state. In the driving state, the driving torque can be released to accelerate the vehicle (corresponding to the battery discharge state), and in the recovery state, it is similar to the chassis braking system to decelerate the vehicle while charging the battery. In other words, in some cases, the vehicle can be decelerated through the recovery state of the motor, and the battery can be charged during the deceleration condition to improve the battery life.

[0063] Based on the characteristics that the motor of new energy vehicles can be in both driving and recovery states, the vehicle control unit (VCU) has added a low-speed creeping function. For vehicles with creeping mode, after entering the creeping mode, PI closed-loop control (Proportional Integral control, PI control) is performed through the speed difference between the target speed and the actual speed, so that the vehicle can eventually reach and stabilize at the target speed. However, for roads with slopes, there is a risk of slipping after entering the creeping mode.

[0064] The specific control idea of ​​the low-speed creeping function of the VCU is: first set the target speed, and then perform PI control based on the actual speed sent by the current anti-lock braking system (ABS) and other means through the speed difference between the target speed and the actual speed, so that the vehicle can finally reach and stabilize at the target speed. That is, when the actual speed > the target speed, the vehicle is decelerated by reducing the creeping torque; when the actual speed < the target speed, the vehicle is accelerated by increasing the creeping torque; which is roughly divided into starting creeping (starting the vehicle from a stationary state or a low-speed state without stepping on the accelerator) and sliding creeping (decelerating the vehicle from a medium-high speed state to a low-speed creeping state without stepping on the brake). At the same time, only the D and R gears have the low-speed creeping function.

[0065] According to the industry standard highway route design specification (JTG D20-2017), the maximum slope of a standard highway does not exceed 10% (the slope is the steepness of the surface unit. The ratio of the vertical height h of the slope to the horizontal distance l is usually called the slope or slope ratio, which is represented by the letter i. That is, the tangent value of the slope angle, which can be written as i=tan slope angle. The most commonly used method to express the slope is the percentage of the elevation difference between two points and their horizontal distance. The calculation formula is as follows: slope = (elevation difference / horizontal distance) x100%); therefore, on flat roads or roads with a slope of less than 10%, through the PI control method of the VCU creep function, when controlling the vehicle in congested road conditions or waiting for red lights, or when the driver wants to decelerate from medium and high speed to low speed driving conditions, or when the driver wants to start again after braking to park, there is no need to repeatedly step on the accelerator and brake pedals to control the vehicle speed, thereby improving the driver's driving experience.

[0066] However, the actual road conditions are very complicated. There are many roads (such as mountain roads, off-road climbing roads and other non-standard roads) with a slope of more than 10%, or even more than 30%. When driving on a road with a large slope, if it is in an uphill state (with the front of the car facing up), whether the driver wants to drive uphill in D gear or reverse down in R gear (without pressing the accelerator or brake pedal), the limitation of the PI control of the VCU creep function (PI control cannot take into account both flat roads and steep slopes at the same time) will cause the vehicle to slip backwards (down the slope) when driving uphill in D gear or reverse down in R gear.

[0067] Similarly, if the vehicle is downhill (front of the vehicle facing down), whether the driver wants to drive downhill in D gear or reverse upward in R gear (without pressing the accelerator or brake pedal), the limitations of the VCU creep function PI control (PI control cannot take into account both flat roads and steep slopes at the same time) will cause the vehicle to slip forward (downward along the slope) when driving downhill in D gear or reverse upward in R gear, giving the driver a very poor driving experience.

[0068] In addition, for downhill roads with large slopes, in the downhill state (front of the vehicle facing down), when the driver wants to decelerate from medium to high speed without braking and enter low-speed creep control driving by gliding, the vehicle will be unable to decelerate and enter low-speed creep control driving. As a result, the driver feels inconsistent with the same driving conditions on flat roads or roads with smaller slopes (on flat roads or roads with smaller slopes, the driver can enter low-speed creep activation state by gliding from medium to high speed without braking), which reduces the driving experience.

[0069] The HHC function in the chassis system is aimed at uphill conditions. When the slope is greater than a certain threshold, when the driver releases the brakes from a stationary state to stepping on the accelerator to move forward in uphill conditions, the chassis HHC function can maintain a large hydraulic braking force for about 2 seconds after releasing the brakes, generating braking force for the wheels to ensure that the vehicle does not slide backward on the uphill road.

[0070] The HDC function in the chassis system is aimed at downhill conditions, allowing the driver to smoothly pass through steep downhill sections without stepping on the brake pedal. As needed, the brake device controls each wheel through hydraulic braking force to move forward slightly faster than the walking speed. At this time, the driver can fully focus on controlling the steering wheel.

[0071] However, not all vehicles are equipped with both HHC and HDC functions. For vehicles that are not equipped with these two functions, the driver is required to quickly coordinate between the accelerator and brake pedals on uphill and downhill roads, which will make the driver feel tired and have a poor driving experience, and there is still a risk of slipping.

[0072] The torque control method and electronic device of the vehicle provided in the embodiment of the present application enter the creep mode when the creep mode is activated and the current vehicle speed meets the creep control condition, determine the target vehicle speed according to the vehicle operation parameters and the preset default vehicle speed; determine the initial control torque according to the vehicle speed difference between the target vehicle speed and the current vehicle speed; determine the slope compensation torque corresponding to the current vehicle speed and the current detected slope according to the target relationship data corresponding to the current gear; perform torque compensation on the initial control torque according to the slope compensation torque to obtain the creep request torque, and control the drive device to output torque according to the creep request torque. Adjust the default vehicle speed in the creep mode according to the vehicle operation parameters to obtain a target vehicle speed that is more suitable for the current driving scene to ensure the stability of the creep process. The initial control torque before compensation is determined based on the speed difference between the target vehicle speed and the current vehicle speed. Then, the slope compensation torque corresponding to the current vehicle speed and the current detected slope is determined based on the target relationship data corresponding to the current gear. When the vehicle speed, gear and slope are different, different slope compensation torques will be obtained to achieve personalized torque compensation for various scenarios in the creep mode, ensure the normal creep driving in different driving scenarios, and control the torque output of the drive device based on the creep request torque after torque compensation to avoid the risk of slipping due to insufficient power.

[0073] A torque control method for a vehicle according to an exemplary embodiment of the present application will be described below with reference to the accompanying drawings.

[0074] In some embodiments, Figure 1 As shown, a torque control method for a vehicle includes:

[0075] Step 101: In response to the creep mode being activated and the current vehicle speed satisfying the creep control condition, the creep mode is entered, and a target vehicle speed is determined according to vehicle operating parameters and a preset default vehicle speed.

[0076] In specific implementation, after the creep mode is activated, the creep mode will not be entered immediately, but it is necessary to further determine whether the current vehicle speed meets the corresponding creep control condition, wherein the creep control condition can be at least one vehicle speed threshold. When the current vehicle speed is greater than the vehicle speed threshold, it is determined that the creep control condition is not met. When the current vehicle speed is less than or equal to the vehicle speed threshold, it is determined that the creep control condition is met. The creep control condition can be a vehicle speed interval. When the current vehicle speed is within the vehicle speed interval, it is determined that the creep control condition is met. When the current vehicle speed is outside the vehicle speed interval, it is determined that the creep control condition is not met.

[0077] Taking the speed range as an example to determine whether the creep control conditions are met, the speed range is generally [0, x+y], where x represents the corresponding target speed, y represents the adjusted reserved speed, and the upper boundary speed can also be max(x)+max(y), where max(x) represents the target speed when the slope is 0, and max(y) represents the maximum reserved value of the adjusted reserved speed. The lower boundary speed of the speed range is 0 to ensure that the scenarios of starting from a standstill to enter the creep mode and entering the creep mode at low speed are covered, ensuring that the creep mode can be directly entered when driving at low speed to perform corresponding torque control.

[0078] When the upper boundary speed is max(x)+max(y), when decelerating at a high speed, the speed between the current speed and the upper boundary speed that needs to be decelerated is smaller, and the creep mode can be entered faster. When x+y is used as the upper boundary speed, the target speed will vary with the vehicle speed, slope, and master cylinder pressure value of the brake master cylinder. It is a dynamically changing value and satisfies max(x)≥x. The value of y depends on the specific configuration information of the vehicle's motor. If the motor performance is high, fast torque adjustment can be achieved, and y can be a smaller value, such as y=2; if the motor performance is poor and fast torque adjustment cannot be achieved, y can be a larger value, such as y=3, and max(y)≥y is satisfied. Among them, after adjusting the reserved vehicle speed to enter the creep mode, the vehicle motor will output the compensated creep request torque, but there may be a difference between the motor torque when entering the creep mode and the creep request torque, so the reserved vehicle speed is adjusted to leave sufficient time for the torque adjustment. While the torque is being adjusted, the vehicle speed is adjusted to the corresponding target speed and the creep driving process is entered.

[0079] After entering the creep mode, the vehicle speed needs to be adjusted to the target speed, so the target speed needs to be determined based on the vehicle operating parameters and the preset default speed. The target speed is the speed at which the vehicle maintains stable driving in the creep mode. However, a fixed target speed will cause the vehicle to slip, so the preset default speed needs to be compensated according to the vehicle operating parameters to ensure that creeping at the target speed will not cause slipping. The compensation is a deceleration process. Creeping at a slower target speed can reduce momentum on a sloped road and reduce the difficulty of speed control to avoid slipping.

[0080] Among them, in creep mode, the vehicle operation parameters related to determining the target speed include the current detection slope, the master cylinder pressure value of the brake master cylinder and the steering wheel angle. Different target speeds can be set according to different current detection slopes (of course, the target speeds under different slopes can also be set to the same value). For example, when driving on a flat road or an uphill / downhill road with a small slope, the target speed can be set to 6kph, but when driving on a steep uphill / downhill road, the target speed can be appropriately reduced for safety reasons. For example, for an uphill road with a slope of >30% or a downhill road with a slope of <-30%, the target speed can be set to 4kph. Among them, the chassis electronic stability system sends the vehicle slope signal to the VCU to obtain the current detection slope; or the chassis electronic stability system sends the vehicle longitudinal acceleration to the VCU, and the VCU calculates the current detection slope based on the longitudinal acceleration. Positive values ​​represent uphill states, and negative values ​​represent downhill states.

[0081] Similarly, for safety reasons, the target vehicle speed can also be corrected according to the steering wheel angle and the master cylinder pressure value of the brake master cylinder after the brake pedal is stepped on. The larger the steering wheel angle, the greater the control difficulty, the larger the correction amplitude, and the smaller the target vehicle speed. The smaller the steering wheel angle, the smaller the control difficulty, the smaller the correction amplitude, and the larger the target vehicle speed. The larger the master cylinder pressure value of the brake master cylinder, the deeper the depth of stepping on the brake pedal, the stronger the driver's desire to slow down, and the smaller the target vehicle speed. The smaller the master cylinder pressure value of the brake master cylinder, the shallower the depth of stepping on the brake pedal, the weaker the driver's desire to slow down, and the larger the target vehicle speed.

[0082] At the same time, the default vehicle speed is corrected according to the current detected slope, the master cylinder pressure value of the brake master cylinder and the steering wheel angle to obtain three corrected vehicle speeds. Then the smallest corrected vehicle speed among the three corrected vehicle speeds is determined as the final target vehicle speed to reduce the difficulty of maintaining the target vehicle speed in creeping form and avoid slipping.

[0083] Step 102: Determine an initial control torque according to the vehicle speed difference between the target vehicle speed and the current vehicle speed.

[0084] In specific implementation, the initial control torque is the torque determined during PI closed-loop control, which is the original torque value before compensation according to the slope and is the basis for torque compensation in creep mode.

[0085] PI closed-loop control is the most commonly used control strategy in control theory. It consists of two parts: proportional control and integral control, which can effectively solve the problems of control response speed and steady-state error.

[0086] Among them, proportional control is the main part of PI closed-loop control, which proportionally amplifies the error between the feedback signal and the target signal, and then uses the amplified signal as the output signal of proportional control. Specifically, proportional control multiplies the error signal by a proportional gain coefficient Kp, and then uses the result as the output signal. The size of the proportional gain coefficient Kp determines the response speed of the control. When Kp is too large, the system will oscillate, otherwise it will cause the system to respond too slowly.

[0087] As another part of PI closed-loop control, integral control integrates the error signal and then uses the integral result as the output signal of integral control. The main function of integral control is to solve the steady-state error problem of the system. When there is a steady-state error in the system, integral control can continuously integrate the error signal and feed the result back to the system to gradually eliminate the error. The integral gain coefficient Ki of integral control needs to be adjusted according to the actual situation of the system. When Ki is too large, the system will amplify the steady-state error, otherwise it will cause the system to respond too slowly.

[0088] The calculation formula for determining the initial control torque through PI closed-loop control can be expressed as:

[0089] N(t)=Kp×V(t)+Ki×∫V(t)dt

[0090] Among them, N(t) represents the initial control torque output at time t, V(t) represents the speed difference between the target vehicle speed at time t and the current vehicle speed, Kp represents the proportional gain coefficient, Ki represents the integral gain coefficient, and t represents time.

[0091] Step 103: Determine the slope compensation torque corresponding to the current vehicle speed and the current detected slope according to the target relationship data corresponding to the current gear.

[0092] In specific implementation, the initial control torque is generally applicable to flat roads or slopes with a gradient of less than 10%. Roads with larger slopes require certain compensation to ensure that there is no risk of slipping. In order to further reduce the risk of slipping on slopes with a gradient of less than 10%, it is necessary to determine the slope compensation torque corresponding to the current vehicle speed and the current detected slope based on the target relationship data corresponding to the current gear position to compensate for the initial control torque. The compensated creep request torque can be applicable to driving scenarios corresponding to different slopes and different vehicle speeds to ensure that there is no slipping in different driving scenarios.

[0093] Exemplarily, the slope compensation torque can be based on the slope compensation torque-slope-vehicle speed three-dimensional map as the target relationship data, wherein the three-dimensional map of the slope compensation torque needs to be set according to the forward gear (D gear) and the reverse gear (R gear), because for uphill road conditions (for example, a road with a slope of 30%), when driving uphill in D gear and reverse downhill in R gear, the D gear needs the positive torque of the creep function slope compensation when driving uphill, while the R gear needs the negative torque of the creep function slope compensation to decelerate when reversing downhill. Therefore, if there is only one three-dimensional map of the slope compensation torque, it cannot meet the needs of the D gear and the R gear at the same time, so the corresponding three-dimensional map needs to be set separately according to the D gear and the R gear.

[0094] The determination of the three-dimensional map requires the low-speed creep verification from the vehicle's stationary state when the brake is released on a flat road (slope of 0%), 5%, 10%, 20%, 30%, 40% and other test field roads with different slopes (in D / R gear, the vehicle head is tested up / down respectively). The calibration personnel can first adjust the Kp and Ki in the VCU creep function (adjust according to the speed difference between the target speed and the current speed) to determine the appropriate initial control torque. Then, the slope compensation torque value that does not cause the vehicle to slip at different slopes and speeds is determined in D gear and R gear respectively to ensure that the vehicle does not slip when driving on the corresponding slope road surface, and the vehicle speed is controlled smoothly. Then, the calibration value of the adjustment result can be added to the three-dimensional map (R gear and D gear correspond to a three-dimensional map respectively), and the three-dimensional map is input into the VCU vehicle control for storage, so that it can be called for subsequent creep control.

[0095] Step 104: Perform torque compensation on the initial control torque according to the slope compensation torque to obtain the creep request torque, and control the drive device to output torque according to the creep request torque.

[0096] In specific implementation, after adding the slope compensation torque function in the VCU creep mode, when the low-speed creep function is activated, the creep request torque = initial control torque + slope compensation torque. The process of determining the creep request torque in different driving scenarios is as follows:

[0097] The current gear is D gear, and the vehicle is in an uphill state (the slope is positive, and the front of the vehicle is facing upward). The vehicle is driving uphill in D gear. At this time, the creep request torque = initial control torque + D gear slope compensation positive torque (in the D gear slope compensation torque map, the area with a positive slope is obtained by looking up the table).

[0098] The current gear is R gear, and the vehicle is in an uphill state (the slope is positive, and the front of the vehicle is facing upward). The vehicle is driving in reverse downward in R gear. At this time, the creep request torque = initial control torque + R gear slope compensation negative torque (in the R gear slope compensation torque map, the area with a positive slope is obtained by looking up the table);

[0099] The current gear is D gear, and the vehicle is in a downhill state (the slope is negative, and the front of the vehicle is facing downward). The D gear is driving downhill. At this time, the creep request torque = initial control torque + D gear slope compensation negative torque (in the D gear slope compensation torque map, the area with a negative slope is obtained by looking up the table);

[0100] The current gear is R gear, and the vehicle is in a downhill state (the slope is negative, the front of the vehicle is facing downward), and the R gear is reversed and driving upward (backward). At this time, the creep request torque = initial control torque + R gear slope compensation positive torque (in the R gear slope compensation torque map, the slope is negative in the area lookup table to obtain).

[0101] Among them, compensating positive torque means increasing the initial control torque, and compensating negative torque means reducing the initial control torque. That is, increasing the torque of the vehicle in the uphill direction, avoiding the risk of slipping caused by too little torque, and improving the user's driving experience.

[0102] In summary, the torque control method of the vehicle provided in the embodiment of the present application can adjust the default vehicle speed in the creep mode according to the vehicle operating parameters, and obtain a target vehicle speed that is more suitable for the current driving scene to ensure the stability of the creep process. The initial control torque before compensation is determined according to the speed difference between the target vehicle speed and the current vehicle speed, and then the slope compensation torque corresponding to the current vehicle speed and the current detected slope is determined according to the target relationship data corresponding to the current gear position. When the vehicle speed, gear position and slope are different, different slope compensation torques will be obtained to achieve personalized torque compensation for various scenes in the creep mode, ensure the normal creep driving in different driving scenes, and control the drive device to output torque according to the creep request torque after torque compensation, avoid the risk of slipping due to insufficient power, and improve the user's driving experience.

[0103] In some embodiments, Figure 2 As shown, the target vehicle speed is determined according to the vehicle operating parameters and the preset default vehicle speed, including:

[0104] Step 201: Determine a slope correction parameter according to a current detected slope in the vehicle operation parameters, and determine a slope-corrected vehicle speed according to the slope correction parameter and a default vehicle speed.

[0105] In specific implementation, first obtain the slope-parameter relationship data between the slope and the slope correction parameter (the larger the slope, the smaller the slope correction parameter), such as the slope-parameter relationship table, the slope-parameter relationship function, etc., query the slope-parameter relationship data according to the current detected slope, and then obtain the corresponding slope correction parameter. Then, the product of the slope correction parameter and the default speed is determined as the slope correction speed. Taking the default speed of 8kph as an example, when driving on a flat road or an uphill / downhill road with a small slope, the slope correction parameter can be 0.9, and the corresponding slope correction speed = 0.9×8=7.2kph. When driving on an uphill road with a slope >30% or a downhill road with a slope <-30%, the slope correction parameter can be 0.75, and the corresponding slope correction speed = 0.75×8=6kph.

[0106] Step 202: determining a steering angle correction parameter according to a steering wheel angle in the vehicle operation parameters, and determining a steering angle correction vehicle speed according to the steering angle correction parameter and a default vehicle speed.

[0107] During specific implementation, for safety reasons, the target vehicle speed can also be corrected according to the steering wheel angle and the master cylinder pressure value of the brake master cylinder after stepping on the brake pedal. The larger the steering wheel angle, the greater the control difficulty, the greater the correction amplitude, and the smaller the target vehicle speed. The smaller the steering wheel angle, the smaller the control difficulty, the smaller the correction amplitude, and the greater the target vehicle speed. Exemplarily, taking the default vehicle speed of 8kph as an example, when the steering wheel angle is 30°, the angle correction parameter is 0.9, and the corresponding angle correction speed = 0.9×8=7.2kph. When the steering wheel angle is 45°, the angle correction parameter is 0.8, and the corresponding angle correction speed = 0.8×8=6.4kph.

[0108] Step 203: Determine a pressure correction parameter according to the master cylinder pressure value of the brake master cylinder in the vehicle operation parameter, and determine a pressure-corrected vehicle speed according to the pressure correction parameter and a default vehicle speed.

[0109] In specific implementation, for safety reasons, the greater the master cylinder pressure value of the brake master cylinder, the deeper the depth of stepping on the brake pedal, the stronger the driver's deceleration intention, and the lower the target vehicle speed. The smaller the master cylinder pressure value of the brake master cylinder, the shallower the depth of stepping on the brake pedal, the weaker the driver's deceleration intention, and the higher the target vehicle speed. For example, taking the default vehicle speed of 8kph as an example, when the master cylinder pressure value is 2Mpa, the angle correction parameter is 0.9, and the corresponding pressure-corrected vehicle speed = 0.9×8=7.2kph. When the master cylinder pressure value is 6Mpa, the angle correction parameter is 0.85, and the corresponding angle-corrected vehicle speed = 0.85×8=6.8kph.

[0110] Step 204: The minimum value among the slope-corrected vehicle speed, the corner-corrected vehicle speed and the pressure-corrected vehicle speed is taken as the target vehicle speed.

[0111] In specific implementation, the slope-corrected speed, the angle-corrected speed and the pressure-corrected speed respectively correct the default speed from different angles. For safety reasons, the minimum value among the slope-corrected speed, the angle-corrected speed and the pressure-corrected speed is used as the target speed, which can meet the requirements of the three corrections at the same time. For example, when the current detected slope is 32%, the steering wheel angle is 45°, and the master cylinder pressure value is 6Mpa, the corresponding slope-corrected speed = 0.75×8 = 6kph, the corresponding angle-corrected speed = 0.8×8 = 6.4kph, and the corresponding angle-corrected speed = 0.85×8 = 6.8kph, among which the minimum is the slope-corrected speed of 6kph. Using the slope-corrected speed of 6kph as the target speed simultaneously meets the safety requirements of the three correction conditions and ensures the safety of creeping driving.

[0112] In some embodiments, Figure 3 As shown, the initial control torque is determined according to the vehicle speed difference between the target vehicle speed and the current vehicle speed, including:

[0113] Step 301: Determine the product of the vehicle speed difference and a preset proportional gain coefficient as the proportional control torque.

[0114] In specific implementation, PI closed-loop control is the most commonly used control strategy in control theory. It consists of two parts: proportional control and integral control, which can effectively solve the problems of control response speed and steady-state error.

[0115] Among them, proportional control is the main part of PI closed-loop control. It proportionally amplifies the error between the feedback signal and the target signal, and then uses the amplified signal as the proportional control torque. The proportional control torque = Kp × V (t). Specifically, the proportional control multiplies the error signal by a proportional gain coefficient Kp, and then uses the result as the output signal. The size of the proportional gain coefficient Kp determines the response speed of the control. When Kp is too large, the system will oscillate, otherwise it will cause the system to respond too slowly.

[0116] Step 302: Perform an integration operation on the vehicle speed difference to obtain an integral value, and determine the product of the integral value and a preset integral gain coefficient as the integral control torque.

[0117] In specific implementation, integral control is another part of PI closed-loop control. Integral control integrates the error signal and then uses the integral result as the integral control torque. The integral control torque = Ki × ∫V(t)dt. The main function of integral control is to solve the steady-state error problem of the system. When there is a steady-state error in the system, integral control can continuously integrate the error signal and feed the result back to the system to gradually eliminate the error. The integral gain coefficient Ki of the integral control needs to be adjusted according to the actual situation of the system. When Ki is too large, the system will amplify the steady-state error, otherwise it will cause the system to respond too slowly.

[0118] Step 303: Determine the sum of the proportional control torque and the integral control torque as the initial control torque.

[0119] In specific implementation, the sum of the proportional control torque and the integral control torque is the initial control torque, and the calculation formula for determining the initial control torque through PI closed-loop control can be expressed as:

[0120] N(t)=Kp×V(t)+Ki×∫V(t)dt

[0121] Among them, N(t) represents the initial control torque output at time t, V(t) represents the speed difference between the target speed and the current speed at time t, Kp represents the proportional gain coefficient, Ki represents the integral gain coefficient, and t represents time. Using PI closed-loop control to determine the initial control torque can effectively solve the problems of slow control response speed and large steady-state error.

[0122] In some embodiments, Figure 4 As shown, determining the slope compensation torque corresponding to the current vehicle speed and the current detected slope according to the target relationship data corresponding to the current gear position includes:

[0123] Step 401: In response to the current gear being a forward gear, the preset forward gear compensation relationship data is determined as the target relationship data.

[0124] In specific implementation, for uphill road conditions, when driving uphill in D gear and reverse downhill in R gear with creeping at low speed, the D gear uphill requires the creeping function slope compensation positive torque, while the R gear reverse downhill requires the creeping function slope compensation negative torque deceleration. If there is only one kind of relationship data, it cannot meet the needs of both D gear and R gear at the same time, so it is necessary to set the corresponding relationship data separately according to D gear and R gear. Among them, the relationship data can be a three-dimensional map of slope-vehicle speed-torque under different gears, or a three-dimensional function relationship. If the current gear is the forward gear, the stored forward gear compensation relationship data is called as the target relationship data.

[0125] Step 402: In response to the current gear being the reverse gear, the preset reverse gear compensation relationship data is determined as the target relationship data.

[0126] In a specific implementation, if the current gear is a forward gear, the stored forward gear compensation relationship data is called as the target relationship data.

[0127] Step 403: Determine the driving state according to the slope value of the current detected slope.

[0128] In specific implementation, if the slope value of the current detected slope is negative, it means that the front of the vehicle is lower than the rear of the vehicle, and the driving state is downhill. If the slope value of the current detected slope is positive, it means that the front of the vehicle is higher than the rear of the vehicle, and the driving state is uphill. Among them, a flat road with a slope of 0 can be used as an uphill state or a downhill state.

[0129] Step 404: Determine torque-speed relationship data according to the driving state and the target relationship data.

[0130] In some embodiments, step 404 includes:

[0131] Step 4041: In response to the target relationship data being the forward gear compensation relationship data, and the driving state being an uphill state, the positive slope region data in the forward gear compensation relationship data is determined as the torque-speed relationship data.

[0132] In specific implementation, if the current gear is D gear, the target relationship data is the forward gear compensation relationship data. If the driving state is an uphill state (the slope is positive, and the front of the vehicle is facing upward), and the slope of the vehicle is a positive value, it can be determined that the current driving scene is uphill driving in D gear. In order to avoid slipping, it is necessary to compensate for the positive torque in the same direction as the initial control torque to drive the vehicle uphill on the basis of the initial control torque. At this time, the creep request torque = initial control torque + D gear slope compensation positive torque.

[0133] For example, if the initial control torque is 20N·M, in the forward gear uphill condition, the direction of the initial control torque is upward along the slope. In order to avoid insufficient upward torque, it is necessary to compensate for the positive torque in the same direction as the initial control torque. For example, the compensated D gear slope compensation positive torque is 5N·M, then the creep request torque = initial control torque + D gear slope compensation positive torque = 20 + 5 = 25N·M. Therefore, the positive slope area data in the forward gear compensation relationship data is determined as the torque-speed relationship data, wherein the positive slope area data is the data corresponding to the positive slope area in the forward gear compensation relationship data, and is used to query the value of the D gear slope compensation positive torque.

[0134] Step 4042: In response to the target relationship data being the reverse gear compensation relationship data, and the driving state being an uphill state, the positive slope area data in the reverse gear compensation relationship data is determined as the torque-speed relationship data.

[0135] In specific implementation, if the current gear is R gear, the target relationship data is the reverse gear compensation relationship data, if the driving state is uphill (the slope is positive, the front of the vehicle is facing upward), and the slope of the vehicle is a positive value, it can be determined that the current driving scene is reverse downward in R gear. In order to avoid slipping, it is necessary to compensate for the negative torque that drives the vehicle uphill on the basis of the initial control torque, which is opposite to the initial control torque. At this time, the creep request torque = initial control torque + R gear slope compensation negative torque.

[0136] For example, if the initial control torque is 20N·M, in the reverse gear downhill reverse condition, the direction of the initial control torque is downward along the slope. In order to avoid excessive downward torque, it is necessary to compensate for the negative torque in the opposite direction of the initial control torque. For example, the compensated R gear slope compensation negative torque is -5N·M, then the creep request torque = initial control torque + R gear slope compensation negative torque = 20-5 = 15N·M. Therefore, the positive slope area data in the reverse gear compensation relationship data is determined as the torque-speed relationship data, wherein the positive slope area data is the data corresponding to the positive slope area in the reverse gear compensation relationship data, which is used to query the value of the R gear slope compensation negative torque.

[0137] Step 4043: In response to the target relationship data being the forward gear compensation relationship data, and the driving state being the downhill state, the negative slope area data in the forward gear compensation relationship data is determined as the torque-speed relationship data.

[0138] In specific implementation, if the current gear is D gear, the target relationship data is the forward gear compensation relationship data. If the driving state is a downhill state (the slope is negative, the front of the vehicle is facing downward), and the slope of the vehicle is a negative value, it can be determined that the current driving scene is downhill driving in D gear. In order to avoid slipping, it is necessary to compensate for the negative torque that drives the vehicle uphill on the basis of the initial control torque, which is opposite to the initial control torque. At this time, the creep request torque = initial control torque + D gear slope compensation negative torque.

[0139] For example, if the initial control torque is 20N·M, in the forward gear downhill condition, the direction of the initial control torque is downward along the slope. In order to avoid excessive downward torque, it is necessary to compensate for the negative torque in the opposite direction of the initial control torque. For example, the compensated +D gear slope compensation negative torque is -5N·M, then the creep request torque = initial control torque +D gear slope compensation negative torque = 20-5 = 15N·M. Therefore, the negative slope area data in the forward gear compensation relationship data is determined as the torque-speed relationship data, wherein the negative slope area data is the data corresponding to the negative slope area in the forward gear compensation relationship data, and is used to query the value of the D gear slope compensation negative torque.

[0140] Step 4044: In response to the target relationship data being the reverse gear compensation relationship data, and the driving state being a downhill state, the negative slope area data in the reverse gear compensation relationship data is determined as the torque-speed relationship data.

[0141] In specific implementation, if the current gear is R gear, the target relationship data is the reverse gear compensation relationship data. If the driving state is downhill (the slope is negative, the front of the vehicle is facing downward), and the slope of the vehicle is a negative value, it can be determined that the current driving scene is downhill driving in R gear. In order to avoid slipping, it is necessary to compensate for the positive torque in the same direction as the initial control torque to drive the vehicle uphill on the basis of the initial control torque. At this time, the creep request torque = initial control torque + R gear slope compensation positive torque.

[0142] Exemplarily, if the initial control torque is 20N·M, in the reverse gear uphill reversing condition, the direction of the initial control torque is upward along the slope. In order to avoid insufficient upward torque, it is necessary to compensate the positive torque in the same direction as the initial control torque. For example, the compensated R gear slope compensation positive torque is 5N·M, then the creep request torque = initial control torque + R gear slope compensation positive torque = 20+5=25N·M, so the negative slope area data in the reverse gear compensation relationship data is determined as the torque-speed relationship data, wherein the negative slope area data is the data corresponding to the negative slope area in the reverse gear compensation relationship data, which is used to query the value of the R gear slope compensation positive torque.

[0143] Compensating for positive torque means increasing the initial control torque, while compensating for negative torque means reducing the initial control torque. That is, increasing the torque of the vehicle in the uphill direction can avoid the risk of slipping caused by too little torque and improve the user's driving experience.

[0144] Step 405: Determine the search torque corresponding to the current vehicle speed in the torque-speed relationship data as the slope compensation torque.

[0145] In specific implementation, after determining the torque-speed relationship data corresponding to the current driving scenario, the current vehicle speed is used as the input for torque confirmation, and the search torque corresponding to the current vehicle speed in the torque-speed relationship data is queried, and the output query torque is the slope compensation torque. The slope compensation torque is used to increase the driving force in the reverse direction of the uphill slope, which can effectively avoid the risk of the vehicle slipping.

[0146] In some embodiments, Figure 5 As shown, judging whether the current vehicle speed meets the creep control condition includes:

[0147] Step 501: Determine a vehicle speed range corresponding to a creep control condition.

[0148] In specific implementation, taking the vehicle speed range as an example to determine whether the creep control conditions are met, the vehicle speed range is generally [0, x+y], where x represents the corresponding target vehicle speed, and y represents the adjusted reserved vehicle speed. The vehicle speed range can also be [0, max(x)+max(y)], where max(x) represents the target vehicle speed when the slope is 0, and max(y) represents the maximum reserved value of the adjusted reserved vehicle speed. The lower boundary speed of the speed range is 0, which can ensure that the scenarios of entering the creep mode from a stationary start and entering the creep mode at low speed are covered, ensuring that the creep mode can be directly entered when driving at low speed to perform corresponding torque control.

[0149] When the upper boundary speed is max(x)+max(y), when decelerating at a high speed, the speed between the current speed and the upper boundary speed that needs to be decelerated is smaller, and the creep mode can be entered faster. When x+y is used as the upper boundary speed, the target speed will vary with the vehicle speed, slope, and master cylinder pressure value of the brake master cylinder. It is a dynamically changing value and satisfies max(x)≥x. The value of y depends on the specific configuration information of the vehicle's motor. If the motor performance is high, fast torque adjustment can be achieved, and y can be a smaller value, such as y=2; if the motor performance is poor and fast torque adjustment cannot be achieved, y can be a larger value, such as y=3, and max(y)≥y is satisfied. Among them, after adjusting the reserved vehicle speed to enter the creep mode, the vehicle motor will output the compensated creep request torque, but there may be a difference between the motor torque when entering the creep mode and the creep request torque, so the reserved vehicle speed is adjusted to leave sufficient time for the torque adjustment. While the torque is being adjusted, the vehicle speed is adjusted to the corresponding target speed and the creep driving process is entered.

[0150] Step 502: In response to the actual speed being less than or equal to the upper boundary speed of the vehicle speed interval, determining that the current vehicle speed satisfies the creep control condition.

[0151] In specific implementation, if the actual speed is less than or equal to the upper boundary speed of the speed range, it means that the vehicle may need to enter the creeping driving state from a low-speed driving state or a stationary state. At this time, the creeping request torque can be directly used as the driving torque of the whole vehicle, so that creeping driving with stable driving at the target speed on any slope can be achieved. Therefore, when the actual speed is less than or equal to the upper boundary speed of the speed range, it is determined that the current speed meets the creeping control conditions.

[0152] Step 503: In response to the actual speed being greater than the upper boundary speed of the vehicle speed interval, it is determined that the current vehicle speed does not satisfy the creep control condition.

[0153] During specific implementation, if the actual speed is greater than the upper boundary speed of the speed range, it means that the vehicle needs to enter the creeping driving state from the medium-to-high speed driving state. Since the creeping state is a low-speed driving state, the entire vehicle needs to be decelerated at this time and cannot enter the creeping mode immediately. Therefore, when the actual speed is less than or equal to the upper boundary speed of the speed range, it is determined that the current speed meets the creeping control conditions.

[0154] This indicates that the vehicle may have entered the creeping driving state from a low-speed driving state or a stationary state. At this time, the creeping request torque can be directly used as the driving torque of the entire vehicle, so that stable creeping driving at the target speed can be achieved on any slope.

[0155] In some embodiments, Figure 6 As shown, after determining that the current vehicle speed does not meet the creep control condition, the following further includes:

[0156] Step 601: Determine the coasting recovery torque.

[0157] In specific implementation, the coasting recovery torque is defined as the requested torque obtained according to the driving mode / vehicle speed / throttle opening, which can be understood as the most basic torque demand. When other functions with higher priority (such as creep function / parking function / adaptive cruise function) are not activated, the motor is controlled to output the coasting recovery torque to drive the vehicle. At this time, the coasting recovery torque can be understood as the resistance torque generated when the vehicle coasts.

[0158] Step 602: Determine the initial slope request compensation torque according to the coasting recovery torque and the current vehicle speed.

[0159] In some embodiments, step 602 includes:

[0160] Step 6021: Determine target three-dimensional compensation relationship data corresponding to the current gear position;

[0161] Step 6022: Determine the retrieved slope request compensation torque corresponding to the coasting recovery torque and the current vehicle speed in the target three-dimensional compensation relationship data as the initial slope request compensation torque.

[0162] In specific implementation, in order to meet the situation where it is necessary to glide into the low-speed creep function without pressing the brake pedal at medium and high speeds, it is necessary to add a slope request compensation torque function to the glide recovery torque function, and increase the compensating negative torque at medium and high speeds to ensure that after releasing the accelerator pedal, the vehicle can decelerate and glide from medium and high speeds to enter the low-speed creep function.

[0163] The request compensation function is mainly to decelerate from medium and high speeds on roads with large slopes. It can be understood as controlling the motor to output negative torque so that the motor can decelerate the vehicle. The deceleration process does not require stepping on the brake pedal to use the motor characteristics to achieve an effect similar to the deceleration of the chassis braking force. There are corresponding three-dimensional compensation relationship data (such as three-dimensional map, three-dimensional function relationship) between the sliding recovery torque-vehicle speed-initial slope request compensation torque, and different gears correspond to different three-dimensional compensation relationship data. The corresponding target three-dimensional compensation relationship data is determined according to the current gear in multiple three-dimensional compensation relationship data. After determining the values ​​of any two of the data, the value of the third data can be determined. After obtaining the sliding recovery torque and the current vehicle speed, the corresponding initial slope request compensation torque can be determined. The initial slope request compensation torque is the torque that needs to be compensated to achieve deceleration when the slope is 0. Among them, the three-dimensional compensation relationship data is obtained by testing in the test road field and stored in the VCU.

[0164] In the case of a large slope, if the initial slope request compensation torque is used to compensate for the coasting recovery torque, the braking force for decelerating the entire vehicle is the combined force of the coasting resistance and the resistance generated by the initial slope request compensation torque. If the slope is large, the component of gravity downward along the slope is greater than the braking force for decelerating the entire vehicle, which will cause the vehicle to continue to accelerate, forcing the driver to step on the brake pedal to decelerate. Therefore, a certain compensation correction is required for the initial slope request compensation torque to ensure that the vehicle can decelerate in the case of a large slope.

[0165] Step 603: Determine the requested compensation coefficient according to the current detected slope and the current vehicle speed.

[0166] In some embodiments, step 603 includes:

[0167] Step 6031: Determine target three-dimensional coefficient relationship data corresponding to the current gear position;

[0168] Step 6032: Determine the retrieval coefficient in the target three-dimensional coefficient relationship data corresponding to the current detected slope and the current vehicle speed as the requested compensation coefficient.

[0169] In specific implementation, there are corresponding three-dimensional coefficient relationship data (such as three-dimensional map, three-dimensional function relationship) between correction coefficient-vehicle speed-slope. Different gears correspond to different three-dimensional coefficient relationship data. After determining the corresponding target three-dimensional coefficient relationship data according to the current gear in multiple three-dimensional coefficient relationship data, the current detected slope and the current vehicle speed are used as the input of the retrieval, and the retrieved value is used as the output of the retrieval, which is the requested compensation coefficient corresponding to the current detected slope and the current vehicle speed. The requested compensation coefficient is a coefficient that corrects the initial slope request compensation torque according to the slope and vehicle speed, to ensure that the vehicle can decelerate under the current vehicle speed and the current detected slope road conditions. Among them, the three-dimensional coefficient relationship data is obtained through experiments in the test road field and stored in the VCU.

[0170] Step 604: Determine the product of the initial slope request compensation torque and the request compensation coefficient as the slope request compensation torque, and determine the sum of the coasting recovery torque and the slope request compensation torque as the requested total torque.

[0171] In specific implementation, the initial slope request compensation torque is corrected by requesting the compensation coefficient to obtain the final slope request compensation torque, that is, the product of the initial slope request compensation torque and the request compensation coefficient is determined as the slope request compensation torque. Then, the sum of the coasting recovery torque and the slope request compensation torque is determined as the requested total torque. Torque control based on the requested total torque can achieve effective deceleration on a slope road without the user stepping on the brake pedal for deceleration control. Among them, the requested total torque is determined based on the real-time detected slope, vehicle speed and torque, so it is a dynamic variable, not a fixed value.

[0172] Step 605: Control the vehicle to decelerate according to the requested total torque until the vehicle speed reaches the upper boundary speed, and determine that the creep control condition is met.

[0173] During specific implementation, the vehicle is decelerated according to the total torque control until the current vehicle speed drops to the upper boundary speed. This determines that the creep control conditions are met, and the creep control mode is entered. The requested total torque is adjusted to the creep request torque, and the current vehicle speed is adjusted to the target speed. The vehicle enters a stable creep driving state, completing the torque control and vehicle speed control after the creep mode is activated, successfully avoiding the risk of slipping caused by sloping roads.

[0174] For example, in an uphill state (the slope is positive and the front of the vehicle is facing upward), when reversing downward in R gear and driving needs to decelerate from medium to high speed to enter low-speed creep mode, the slope request compensation torque is the negative torque of the slope compensation in R gear. At this time, the total torque requested at medium and high speeds = the coasting recovery torque + the negative torque of the slope compensation in R gear.

[0175] In downhill state (slope is negative, vehicle head is pointing downward), when driving downhill in gear D and need to decelerate from medium to high speed to enter low-speed creep mode, the slope compensation torque requested is the negative torque of slope compensation in gear D. At this time, the total torque requested at medium to high speed = the coasting recovery torque + the negative torque of slope compensation in gear D. Negative torque indicates resistance torque, which is in the same direction as the coasting recovery torque and is used to decelerate the vehicle.

[0176] In summary, for vehicles without HHC configuration, the vehicle torque control method provided in the embodiment of the present application can be used to avoid rolling. The specific application process is as follows:

[0177] Among the exit conditions of the creep mode, an exit condition is added that sets different master cylinder pressure thresholds of the brake master cylinder according to different slopes. At the same time, a delay function is added to the master cylinder pressure threshold. The purpose is that as the slope increases, the set value of the master cylinder pressure threshold also becomes larger, and the size of the master cylinder pressure value is related to the depth (stroke) of the brake pedal. Therefore, if the driver releases the brake pedal after a short time, or steps on the brake pedal very shallowly, the creep mode will not be exited. The creep mode will only be exited when the brake pedal is stepped on deeply and the delay time is met.

[0178] At the same time, a function to request the chassis electronic parking brake system (Electrical Park Brake, EPB) to activate is added, and different master cylinder pressure thresholds are set according to different slopes. At the same time, a delay function is added to the master cylinder pressure threshold. That is, when the master cylinder pressure after the driver's brake pedal depth conversion exceeds the threshold and continues to meet the delay time, EPB activation will be requested; when EPB is activated, the creep function will exit.

[0179] Then, for uphill conditions, if the driver releases the brake pedal after a short time, or steps on the brake pedal shallowly (the master cylinder pressure value is very small), the creep mode will not be exited. For uphill conditions, when the creep mode is activated, the creep request torque will generate enough driving force to prevent the vehicle from sliding backward. When the brake pedal is stepped on deeply (the master cylinder pressure is large) and the duration is long enough, EPB will take over again. At this time, even if the creep mode is exited, EPB can still ensure that the vehicle does not slide on the slope.

[0180] For vehicles without HDC configuration, the vehicle torque control method provided in the embodiment of the present application can be used to avoid rolling. The specific application process is as follows:

[0181] For downhill conditions, the vehicle can be controlled by entering creep mode and allowing the motor to output creep request torque to control the vehicle at a low and stable speed. At this time, the driver does not need to brake to control the vehicle and can focus on controlling the steering wheel, which improves the driving experience while avoiding slipping.

[0182] The torque control method for the vehicle provided by the embodiment of the present application can make the vehicle stable at low speeds under different slopes / gears, whether it is starting from a standstill to entering the creep mode, or sliding into the creep mode at medium and high speeds. During the whole process, the driver greatly reduces the frequency of stepping on the accelerator and brake pedals, while ensuring that the vehicle will not slip on steep uphill and downhill roads. No complicated theoretical calculations are required during use, only different relationship data need to be determined in the test field. For vehicles without HHC and HDC configurations, the torque control method for the vehicle provided by the embodiment of the present application can achieve similar effects and enhance the user's driving experience: under uphill conditions, when the creep mode is activated, the creep positive torque output is given to the motor to prevent the vehicle from slipping backwards; and under downhill conditions, the creep mode controls the vehicle to travel downhill at a low speed, relying on the motor for deceleration control to prevent the vehicle from slipping.

[0183] In some embodiments, Figure 7 As shown, the vehicle torque control method also includes:

[0184] Step 701: monitor the accelerator pedal's accelerator pedal stroke, the brake pedal's brake pedal stroke and the real-time vehicle speed in real time.

[0185] In specific implementation, in creep mode, the user does not need to step on the brake pedal for deceleration control, nor does the user need to step on the accelerator pedal for acceleration control. If the accelerator pedal's accelerator pedal stroke or the brake pedal's brake pedal stroke is detected, it means that the user has taken over the vehicle control. However, in order to avoid the vehicle slipping, certain conditions must be met before exiting the creep mode. If the real-time speed of the vehicle is too high, it means that the creep mode cannot constrain the vehicle's speed, and it is also necessary to exit the creep mode and switch to a safer mode to control the vehicle speed, or prompt the user to manually limit the speed.

[0186] Step 702: Determine the throttle request torque corresponding to the throttle pedal stroke and the brake master cylinder pressure value corresponding to the brake pedal stroke.

[0187] In specific implementation, different throttle pedal strokes correspond to different requested torques, and the corresponding throttle requested torque is determined based on the detected throttle pedal stroke, and the throttle requested torque is the requested torque under manual control by the user. Different brake pedal strokes correspond to different brake master cylinder pressure values, and the corresponding brake master cylinder pressure values ​​are determined based on the detected brake pedal stroke, and the brake master cylinder pressure values ​​are the brake master cylinder pressure values ​​under manual control by the user.

[0188] Step 703: In response to the real-time vehicle speed being greater than or equal to the preset exit speed, and the first duration for which the real-time vehicle speed is greater than or equal to the exit speed being greater than or equal to the preset first delay threshold, exit the creep mode.

[0189] Among them, the exit speed is greater than or equal to the upper boundary speed.

[0190] In specific implementation, if the real-time vehicle speed is greater than or equal to the preset exit speed, it means that the creep mode cannot complete deceleration or prevent the vehicle from slipping, in order to avoid false detection of the real-time vehicle speed caused by speed fluctuations. Furthermore, it is necessary to monitor in real time the first duration of the real-time vehicle speed being greater than or equal to the exit speed. If the first duration is greater than or equal to the preset first delay threshold, it means that the real-time vehicle speed is not a fluctuation signal, but an actual excessive speed, and it is necessary to exit the creep mode to ensure that the speed can be limited to continue to increase, thereby ensuring driving safety. If the first duration is less than the preset first delay threshold, it means that the real-time vehicle speed is a fluctuation signal and the creep mode will not be exited.

[0191] Step 704: In response to the throttle request torque being greater than or equal to the creep request torque, and the second duration for which the throttle request torque is greater than or equal to the creep request torque being greater than or equal to a preset second delay threshold, exit the creep mode.

[0192] In specific implementation, if the throttle request torque is less than the creep request torque, the creep mode is maintained, because releasing the creep mode at this time will cause the vehicle's request torque to decrease, causing the vehicle to slip. When the throttle request torque is greater than or equal to the creep request torque, the vehicle's request torque increases or remains unchanged when the creep mode is released, and exiting the creep mode will not cause the risk of slipping, so the creep mode can be exited.

[0193] Furthermore, it is also necessary to monitor in real time the second duration of the throttle request torque being greater than or equal to the creep request torque. If the second duration is greater than or equal to the preset second delay threshold, it indicates that the driver does have a corresponding acceleration demand, and the creep mode is exited and the throttle pedal request that meets the requirements is responded to. If the second duration is less than the preset second delay threshold, it indicates that the driver may have accidentally touched the throttle pedal, and the driver does not have a corresponding acceleration demand, and there is no need to exit the creep mode.

[0194] Step 705: In response to the master cylinder pressure value being greater than or equal to a preset pressure threshold, and the third duration of the master cylinder pressure value being greater than or equal to the preset pressure threshold being greater than or equal to a preset third delay threshold, exit the creep mode.

[0195] In specific implementation, if the brake master cylinder pressure value is less than the preset pressure threshold, the creep mode is maintained, because releasing the creep mode at this time will cause the vehicle's output torque to decrease, causing the vehicle to slip. When the brake master cylinder pressure value is greater than or equal to the preset pressure threshold, the vehicle's output torque increases or remains unchanged when the creep mode is released, and exiting the creep mode will not cause the risk of slipping, so the creep mode can be exited.

[0196] Furthermore, it is also necessary to monitor in real time the third duration of the master cylinder pressure value being greater than or equal to the preset pressure threshold. If the third duration is greater than or equal to the preset third delay threshold, it means that the driver does have a corresponding braking deceleration demand, and the electronic parking brake (EPB) control will be activated, and it is necessary to exit the creep mode and perform deceleration or parking control. If the third duration is less than the preset third delay threshold, it means that the driver may have accidentally touched the brake pedal, and the driver does not have a corresponding deceleration or parking demand, and there is no need to exit the creep mode.

[0197] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the described method.

[0198] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0199] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a torque control device for a vehicle.

[0200] refer to Figure 8 , the torque control device of the vehicle comprises:

[0201] The creep mode entry module 10 is configured to: in response to the creep mode being activated and the current vehicle speed meeting the creep control condition, enter the creep mode, and determine the target vehicle speed according to the vehicle operating parameters and the preset default vehicle speed;

[0202] The initial torque determination module 20 is configured to: determine the initial control torque according to the vehicle speed difference between the target vehicle speed and the current vehicle speed;

[0203] The compensation torque determination module 30 is configured to: determine the slope compensation torque corresponding to the current vehicle speed and the current detected slope according to the target relationship data corresponding to the current gear position;

[0204] The creep torque determination module 40 is configured to perform torque compensation on the initial control torque according to the slope compensation torque to obtain the creep request torque, and control the driving device to output torque according to the creep request torque.

[0205] For the convenience of description, the above device is described in terms of functions divided into various modules. Of course, when implementing the present application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0206] The device of the above embodiment is used to implement the torque control method of the vehicle corresponding to any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be repeated here.

[0207] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the torque control method for the vehicle described in any of the above embodiments is implemented.

[0208] Fig. 9 A more specific schematic diagram of the hardware structure of an electronic device provided in this embodiment is shown, and the device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are connected to each other through the bus 1050 in the device.

[0209] The processor 1010 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0210] The memory 1020 may be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 may store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program codes are stored in the memory 1020 and are called and executed by the processor 1010.

[0211] The input / output interface 1030 is used to connect the input / output module to realize information input and output. The input / output module can be configured in the device as a component (not shown in the figure), or it can be externally connected to the device to provide corresponding functions. The input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0212] The communication interface 1040 is used to connect a communication module (not shown) to realize communication interaction between the device and other devices. The communication module can realize communication through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0213] The bus 1050 includes a path that transmits information between the various components of the device (eg, the processor 1010 , the memory 1020 , the input / output interface 1030 , and the communication interface 1040 ).

[0214] It should be noted that, although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040 and the bus 1050, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, it can be understood by those skilled in the art that the above device may also only include the components necessary for implementing the embodiments of the present specification, and does not necessarily include all the components shown in the figure.

[0215] The electronic device of the above embodiment is used to implement the torque control method of the vehicle corresponding to any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be repeated here.

[0216] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the torque control method of the vehicle as described in any of the above embodiments.

[0217] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by 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 technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0218] The computer instructions stored in the storage medium of the above embodiments are used to enable the computer to execute the vehicle torque control method described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0219] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, the present application also provides a vehicle, including the electronic device or the torque control device of the vehicle of the above-mentioned embodiments, and the torque control method of the vehicle as described in any of the above-mentioned embodiments is executed through the electronic device or the torque control device of the vehicle of the above-mentioned embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0220] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0221] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present application difficult to understand, the known power / ground connections to the integrated circuit (IC) chip and other components may or may not be shown in the provided drawings. In addition, the device may be shown in the form of a block diagram to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present application are to be implemented (that is, these details should be fully within the scope of understanding of those skilled in the art). Where specific details (e.g., circuits) are set forth to describe exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details or with changes in these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0222] Although the present application has been described in conjunction with specific embodiments of the present application, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the discussed embodiments.

[0223] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A method for controlling torque of a vehicle, characterized in that: include: In response to the creep mode being activated and the current vehicle speed satisfying the creep control condition, the creep mode is entered, and a target vehicle speed is determined according to the vehicle operating parameters and a preset default vehicle speed; Wherein, judging whether the current vehicle speed satisfies the creep control condition comprises: determining a vehicle speed interval corresponding to the creep control condition; in response to the actual speed being less than or equal to the upper boundary vehicle speed of the vehicle speed interval, determining that the current vehicle speed satisfies the creep control condition; in response to the actual speed being greater than the upper boundary vehicle speed of the vehicle speed interval, determining that the current vehicle speed does not satisfy the creep control condition; determining an initial control torque according to a vehicle speed difference between the target vehicle speed and the current vehicle speed; Determining a slope compensation torque corresponding to the current vehicle speed and the current detected slope according to target relationship data corresponding to the current gear; wherein the relationship data is a three-dimensional map of the slope compensation torque, the slope, and the vehicle speed; Wherein, determining the slope compensation torque corresponding to the current vehicle speed and the current detected slope according to the target relationship data corresponding to the current gear position includes: In response to the current gear being a forward gear, determining preset forward gear compensation relationship data as the target relationship data; In response to the current gear being a reverse gear, determining preset reverse gear compensation relationship data as the target relationship data; determining a driving state according to a slope value of the current detected slope; determining torque-speed relationship data according to the driving state and the target relationship data; determining a search torque corresponding to the current vehicle speed in the torque-speed relationship data as the slope compensation torque; Performing torque compensation on the initial control torque according to the slope compensation torque to obtain a creep request torque, and controlling a driving device to output torque according to the creep request torque; In response to determining that the current vehicle speed does not satisfy the creep control condition, determining a coasting recovery torque; determining an initial slope request compensation torque according to the coasting recovery torque and the current vehicle speed; determining a target correction coefficient relationship according to the current gear position, and determining a request compensation coefficient corresponding to the current detected slope and the current vehicle speed according to the target correction coefficient relationship; determining a product of the initial slope request compensation torque and the request compensation coefficient as a slope request compensation torque, and determining a sum of the coasting recovery torque and the slope request compensation torque as a requested total torque; The vehicle is controlled to decelerate according to the requested total torque until it decelerates to the upper boundary vehicle speed, and it is determined that the creep control condition is satisfied.

2. The vehicle torque control method according to claim 1, characterized in that: Determining the target vehicle speed according to the vehicle operating parameters and the preset default vehicle speed includes: Determine a slope correction parameter according to the current detected slope in the vehicle operation parameter, and determine a slope-corrected vehicle speed according to the slope correction parameter and the default vehicle speed; Determining a steering angle correction parameter according to a steering wheel angle in the vehicle operation parameter, and determining a steering angle correction vehicle speed according to the steering angle correction parameter and the default vehicle speed; Determine a pressure correction parameter according to a master cylinder pressure value of a brake master cylinder in the vehicle operation parameter, and determine a pressure-corrected vehicle speed according to the pressure correction parameter and the default vehicle speed; The minimum value among the slope-corrected vehicle speed, the corner-corrected vehicle speed, and the pressure-corrected vehicle speed is used as the target vehicle speed.

3. The vehicle torque control method according to claim 1, characterized in that: The determining the initial control torque according to the vehicle speed difference between the target vehicle speed and the current vehicle speed includes: Determine the product of the vehicle speed difference and a preset proportional gain coefficient as the proportional control torque; Performing an integration operation on the vehicle speed difference to obtain an integral value, and determining the product of the integral value and a preset integral gain coefficient as the integral control torque; The sum of the proportional control torque and the integral control torque is determined as the initial control torque.

4. The vehicle torque control method according to claim 1, characterized in that: The step of determining the torque-speed relationship data according to the driving state and the target relationship data comprises: In response to the target relationship data being the forward gear compensation relationship data and the driving state being an uphill state, determining the positive slope region data in the forward gear compensation relationship data as the torque-speed relationship data; In response to the target relationship data being reverse gear compensation relationship data and the driving state being an uphill state, determining the positive slope region data in the reverse gear compensation relationship data as the torque-speed relationship data; In response to the target relationship data being the forward gear compensation relationship data and the driving state being a downhill state, determining the negative slope region data in the forward gear compensation relationship data as the torque-speed relationship data; In response to the target relationship data being the reverse gear compensation relationship data and the driving state being a downhill state, negative gradient region data in the reverse gear compensation relationship data is determined as the torque-speed relationship data.

5. The vehicle torque control method according to claim 1, characterized in that: Also includes: Real-time monitoring of the accelerator pedal's accelerator pedal stroke, the brake pedal's brake pedal stroke and the real-time vehicle speed; determining an accelerator request torque corresponding to the accelerator pedal stroke and a brake master cylinder pressure value corresponding to the brake pedal stroke; In response to the real-time vehicle speed being greater than or equal to a preset exit vehicle speed, and the first duration of the real-time vehicle speed being greater than or equal to the exit vehicle speed being greater than or equal to a preset first delay threshold, exiting the creep mode; wherein the exit vehicle speed is greater than or equal to an upper boundary vehicle speed; or, In response to the throttle request torque being greater than or equal to the creep request torque, and the second duration for which the throttle request torque is greater than or equal to the creep request torque being greater than or equal to a preset second delay threshold, exiting the creep mode; or, In response to the master cylinder pressure value being greater than or equal to a preset pressure threshold, and a third duration of the master cylinder pressure value being greater than or equal to the preset pressure threshold being greater than or equal to a preset third delay threshold, the creep mode is exited.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the method according to any one of claims 1 to 5 is implemented.

7. A vehicle, characterized in that: Comprising the electronic device as claimed in claim 6.

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