Vehicle slope parking control method and device, new energy vehicle and storage medium

Abstract

The invention relates to a vehicle slope parking control method and device, a new energy vehicle and a storage medium. The method comprises the steps that under the condition that a motor hill-holding function of a vehicle is activated, a hill-holding torque initial value is determined, and a vehicle motor is controlled based on the hill-holding torque initial value so that the vehicle can decelerate and hold a slope; in the deceleration hill-holding process, the vehicle speed change rate of the vehicle is obtained, and the corresponding torque variable quantity and the corresponding torque gradient are obtained based on the vehicle speed change rate; correcting the slope-holding torque initial value based on the torque gradient and the torque variation to obtain at least one slope-holding torque target value; and the torque output of the vehicle motor is adjusted to the slope parking torque target value so that the vehicle can be parked on the slope. The method can improve the accuracy of the vehicle parking on the slope and ensure the driving safety.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a vehicle hill-holding control method, device, new energy vehicle, computer-readable storage medium, and computer program product. Background Art

[0002] To achieve the goal of holding a vehicle on a hill, the vehicle's ESC (Electronic Stability Control) module is usually required. For vehicles equipped with motors, using the motor to hold the vehicle on a hill is another way to achieve holding the vehicle on a hill, but the corresponding holding accuracy needs to be improved, such as the vehicle may slip. Summary of the invention

[0003] Based on this, it is necessary to provide a vehicle holding hill control method, device, new energy vehicle, computer readable storage medium and computer program product to improve the accuracy of the vehicle holding hill in response to the above technical problems.

[0004] In a first aspect, the present application provides a vehicle hill-holding control method, the method comprising:

[0005] When the motor holding hill function of the vehicle is activated, determining an initial value of the holding hill torque, and controlling the vehicle motor based on the initial value of the holding hill torque to decelerate the vehicle and hold the vehicle on the hill;

[0006] During the deceleration and hill-holding process, the vehicle speed change rate is obtained, and the corresponding torque change amount and the corresponding torque gradient are obtained based on the vehicle speed change rate;

[0007] The initial value of the hill-holding torque is corrected based on the torque gradient and the torque variation to obtain at least one hill-holding torque target value;

[0008] The torque output of the vehicle motor is adjusted to a target value of the holding torque to keep the vehicle on the hill.

[0009] In one embodiment, obtaining a corresponding torque gradient based on a vehicle speed change rate includes:

[0010] When the absolute value of the vehicle speed change rate is greater than the preset threshold range, the torque gradient corresponding to the vehicle speed change rate is determined to be the first torque gradient; when the absolute value of the vehicle speed change rate is less than the preset threshold range, the torque gradient corresponding to the vehicle speed change rate is determined to be the second torque gradient or the third torque gradient; when the absolute value of the vehicle speed change rate is within the preset threshold range, the torque gradient corresponding to the vehicle speed change rate is determined to be the fourth torque gradient; wherein the second torque gradient or the third torque gradient is less than the first torque gradient and greater than the fourth torque gradient.

[0011] In one embodiment, the second torque gradient is greater than the third torque gradient; when the absolute value of the vehicle speed change rate is less than a preset threshold range, determining the torque gradient corresponding to the vehicle speed change rate as the second torque gradient or the third torque gradient includes:

[0012] When the absolute value of the vehicle speed change rate is less than a preset threshold range, determining the road slope on which the vehicle is located;

[0013] When the road slope indicates that the vehicle is on an uphill slope, the torque gradient corresponding to the vehicle speed change rate is determined to be the second torque gradient; when the road slope indicates that the vehicle is on a downhill slope, the torque gradient corresponding to the vehicle speed change rate is determined to be the third torque gradient.

[0014] In one embodiment, obtaining the corresponding torque change based on the vehicle speed change rate includes:

[0015] Get the vehicle's mass and wheel rolling radius;

[0016] Determine the torque change required by the vehicle motor based on the vehicle speed change rate, vehicle mass and wheel rolling radius.

[0017] In one of the embodiments, the initial value of the hill-holding torque is corrected based on the torque gradient and the torque change to obtain at least one hill-holding torque target value, including: successively adjusting the initial value of the hill-holding torque according to the torque gradient until the cumulative adjustment amount reaches the torque change amount, thereby obtaining at least one hill-holding torque target value.

[0018] In one embodiment, the initial value of the hill-holding torque is adjusted successively according to the torque gradient, including:

[0019] When the absolute value of the vehicle speed change rate is greater than a preset threshold range, the initial value of the hill-holding torque is gradually reduced according to the first torque gradient;

[0020] When the absolute value of the vehicle speed change rate is less than a preset threshold range, the initial value of the hill-holding torque is gradually increased according to the second torque gradient or the third torque gradient;

[0021] When the absolute value of the vehicle speed change rate is within the preset threshold range, the upper and lower limit averages of the preset threshold range are determined; when the absolute value of the vehicle speed change rate is less than the upper and lower limit averages, the initial value of the hill-holding torque is gradually increased according to the fourth torque gradient; when the absolute value of the vehicle speed change rate is greater than the upper and lower limit averages, the initial value of the hill-holding torque is gradually reduced according to the fourth torque gradient.

[0022] In one embodiment, determining the initial value of the hill-holding torque includes:

[0023] Determine the driving information of the vehicle;

[0024] When the driving information meets the preset hill-holding condition, the motor torque value corresponding to the slope of the vehicle in the current cycle is recorded;

[0025] The initial value of the hill-holding torque is determined based on the recorded motor torque values ​​within a preset number of cycles.

[0026] In a second aspect, the present application also provides a vehicle hill-holding control device, comprising:

[0027] A first hill-holding module is used to determine an initial hill-holding torque value when a hill-holding function of a motor of the vehicle is activated, and control the motor of the vehicle based on the initial hill-holding torque value to decelerate the vehicle and hold the vehicle on the hill;

[0028] A determination module is used to obtain the vehicle speed change rate during the deceleration and hill-holding process, and obtain the corresponding torque change amount and the corresponding torque gradient based on the vehicle speed change rate; correct the initial hill-holding torque value based on the torque gradient and the torque change amount to obtain at least one hill-holding torque target value;

[0029] The second hill-holding module is used to adjust the torque output of the vehicle motor to a hill-holding torque target value so that the vehicle can stay on the hill.

[0030] In a third aspect, the present application further provides a new energy vehicle, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the vehicle hill-holding control method in the aforementioned first aspect when executing the computer program.

[0031] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the vehicle hill-holding control method in the aforementioned first aspect are implemented.

[0032] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of the vehicle hill-holding control method in the aforementioned first aspect.

[0033] The above-mentioned vehicle holding hill control method, device, new energy vehicle, computer-readable storage medium and computer program product, by first determining the initial value of the holding hill torque when the motor holding hill function of the vehicle is activated to control the vehicle to decelerate and hold the hill; and determine the corresponding torque change and torque gradient according to the speed change rate during the deceleration and holding hill process, and correct the initial value of the holding hill torque by the torque change and torque gradient to obtain the holding hill torque target value, so that the holding hill torque target value can meet the actual holding hill demand of the vehicle; and realize the vehicle holding the hill according to the holding hill torque target value. That is, the vehicle is first decelerated and held on the hill, and adjustments are made according to the actual situation of the vehicle decelerating and holding on the hill to achieve accurate holding on the hill. This can achieve more accurate vehicle holding on the hill, avoid the situation that the initial value of the holding hill torque has errors and cannot match the actual holding hill demand of the vehicle, etc., which affects the accuracy of the vehicle holding on the hill. At the same time, it can achieve the vehicle holding on the hill when the car brakes fail, thereby ensuring driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of a first flow chart of a vehicle hill-holding control method in one embodiment;

[0036] Figure 2 A second flow chart of a vehicle holding hill control method in one embodiment;

[0037] Figure 3 A third flow chart of a vehicle hill-holding control method in one embodiment;

[0038] Figure 4 A fourth flow chart of a vehicle hill-holding control method in one embodiment;

[0039] Figure 5 is a structural block diagram of a vehicle hill-holding control device in one embodiment;

[0040] Figure 6 Schematic diagram of the internal structure of a new energy vehicle in one embodiment. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] Before describing the technical solution of this application in detail, the terms / nouns involved are explained as follows:

[0043] Traditional braking systems, including traditional brake systems, mainly control the deceleration and stopping process of the vehicle by adjusting the clamping torque.

[0044] The motor and motor controller, where the motor is the core component that converts electrical energy into mechanical energy and provides power when the vehicle is driving. The motor controller is responsible for controlling the motor's speed and torque output. It receives instructions from the vehicle control system and adjusts the motor's working state so that the motor can achieve the functions of acceleration, deceleration and braking. Specifically, the motor controller can change the motor's working state by adjusting the current and voltage, and decide whether the motor drives the vehicle forward or recovers energy.

[0045] Stalled rotor is a situation where the motor still outputs torque when the speed is 0 rpm.

[0046] D gear (Drive gear) is the vehicle's forward gear. Normally, the motor should rotate forward at this time and the motor speed should be a positive value. If the motor rotates backward at this time, it indicates that the motor is reversed.

[0047] R gear (Reverse gear) is the reverse gear of the vehicle. Under normal circumstances, the motor should rotate backward at this time and the motor speed should be a negative value; if the motor rotates forward at this time, it indicates that the motor is reversed.

[0048] Among them, the motor and the motor controller can also constitute an electric braking system. The electric braking system can be understood as adjusting the reverse torque of the motor through the motor controller to achieve vehicle deceleration or parking. In this process, the vehicle is braked by converting electrical energy into mechanical energy. The principles involved include energy recovery and braking control. Energy recovery can be understood as when the vehicle decelerates or stops, the motor controller controls the motor to generate reverse torque, converts the vehicle's kinetic energy into electrical energy, and stores it back in the battery, thereby extending the cruising range. This control method can reduce dependence on traditional mechanical brakes. Correspondingly, the electric braking process can be understood as the process of controlling vehicle braking mainly through the electric braking system.

[0049] Vehicle speed change rate. In this application, the vehicle speed change rate can be understood as the vehicle acceleration, which represents the change in vehicle speed per unit time. The actual calculated vehicle speed change rate can be positive or negative. For example, during deceleration, the vehicle speed change rate is generally negative, and during acceleration, the vehicle speed change rate is generally positive. However, in this application, the descriptions related to the size of the vehicle speed change rate, including size comparisons, size correlation descriptions, etc., are all discussions of its absolute value. Correspondingly, the threshold or threshold range corresponding to the vehicle speed change rate is a positive value.

[0050] As mentioned above, for vehicles equipped with motors, they can hold the vehicle on a slope by using the motors, but there are technical problems such as poor accuracy in holding the vehicle on a slope by using the motors. At the same time, from the perspective of vehicle driving safety, if there is a problem with the vehicle's brakes, such as failure, then holding the vehicle on a slope by using the motors provides another braking capability to achieve emergency braking and keep the vehicle on the slope as much as possible. Therefore, how to use the motors to hold the vehicle on a slope to ensure driving safety in the event of brake failure is another interpretation of the aforementioned technical problem.

[0051] To solve the above problems, the present application proposes that, when the vehicle's motor hill-holding function is activated, the initial value of the hill-holding torque can be first determined to control the vehicle's deceleration and hill-holding; the corresponding torque correction amplitude is determined in combination with the vehicle speed change rate during the deceleration and hill-holding process, and the initial value of the hill-holding torque is corrected based on the corresponding torque correction amplitude to obtain the hill-holding torque target value, and the motor is controlled based on the hill-holding torque target value, which can improve the accuracy of the vehicle's hill-holding stop based on the motor and ensure driving safety at the same time.

[0052] In one embodiment, Figure 1 As shown, a vehicle holding hill control method is provided. This embodiment uses the method applied to a new energy vehicle as an example for illustration. It can be understood that the method can also be applied to other types of vehicles, as long as the vehicle is equipped with a motor and a motor controller, and the motor and the motor controller can provide driving force for the vehicle. In this embodiment, the method includes steps S101 to S104:

[0053] Step S101: when the motor holding hill function of the vehicle is activated, determining an initial value of the holding hill torque, and controlling the vehicle motor based on the initial value of the holding hill torque to decelerate the vehicle and hold the vehicle on the hill.

[0054] Among them, the motor or vehicle motor can be a motor that provides driving force when the vehicle is driving normally, that is, a driving motor. When it is necessary to hold the vehicle on a hill, the motor is locked to provide the torque required for holding the hill. Of course, it can also be other motors in the vehicle, as long as the motor can provide the torque required for the vehicle to hold the hill by locking the motor.

[0055] Among them, the motor holding hill function can be a function for controlling the motor in the vehicle to hold the hill. In some cases, it is also called a motor braking function or an electric braking function. Exemplarily, the activation of the motor holding hill function can be like other functions in the vehicle, such as reversing images, which can be automatically activated when the preset conditions are met, and of course, it can also be automatically turned off when the preset conditions are met. Exemplarily, the preset conditions may include automatic activation conditions, for example, the driver's voice commands can be captured, and when the voice commands indicate that the hill holding function is required, the motor holding hill function can be automatically activated; of course, specific function buttons, keys, etc. can also be set, just like the vehicle's turn signal lever, emergency light button, etc., when it is pressed by the driver, it indicates that the hill holding function is required, and the motor holding hill function can be automatically activated.

[0056] The initial value of the hill-holding torque may be the initial torque required for the vehicle motor to hold the vehicle on a hill.

[0057] For example, the initial value of the on-hill holding torque corresponding to the motor of the vehicle can be determined by looking up a table. For example, a relationship table corresponding to the slope of the vehicle and the initial value of the on-hill holding torque. For example, the table here can be preset, for example, obtained by preliminary experimental statistics. In this way, the initial value of the on-hill holding torque can be determined more quickly and accurately.

[0058] For example, the vehicle's previous hill-holding conditions can be recorded, such as the torque required for the vehicle to hold the hill under different slopes and vehicle speeds in the past, so that the initial value of the hill-holding torque can be determined based on the recorded hill-holding conditions. In some possible embodiments, the recorded required torque can be the torque of the motor and / or the clamping torque provided by the brake system.

[0059] Step S102: During the process of decelerating and stopping on a slope, the vehicle speed change rate is obtained, and the corresponding torque change amount and the corresponding torque gradient are obtained based on the vehicle speed change rate.

[0060] The vehicle speed change rate may be information or data that characterizes the speed change of the vehicle during the process of decelerating and stopping on a slope, and may be positive or negative. For example, the vehicle speed change rate may be negative when the vehicle speed decreases and positive when the vehicle speed increases. In some possible embodiments, the vehicle speed at different times may be calculated by the wheel speed or the vehicle's drive motor speed to determine the vehicle speed change rate.

[0061] The torque variation may be a variation of the hill-holding torque required by the motor of the vehicle. For example, the torque variation may be based on an initial hill-holding torque value.

[0062] Among them, the torque gradient can be for the torque change. Exemplarily, the torque gradient can be used to regulate the speed of change corresponding to the torque change. For example, when the torque change is 100 (Nm, Newton meters), the corresponding torque gradient can be 10Nm, or 20Nm, etc. Exemplarily, different torque gradient sizes can correspond to different actual needs. For example, when the vehicle is in a state of high danger or emergency, the corresponding torque gradient can be larger, otherwise, it can be smaller. The torque gradient can be a specific torque value, such as the aforementioned 10Nm, or it can be a ratio or percentage, such as 20% or 0.2, etc. Assuming that the torque change is 100 (Nm, Newton meters), then the torque gradient relative to the torque change is 20%, that is, 20Nm.

[0063] After the above steps, the vehicle is decelerated and held on the slope. The initial value of the holding torque may correspond to a poor holding effect. For example, when the vehicle is holding on the slope during the uphill process, the initial value of the holding torque is too small, and the vehicle may slip backward. In this regard, it can be "corrected", that is, firstly "preliminary holding on the slope" is performed through the initial value of the holding torque, that is, deceleration and holding on the slope, and then the "preliminary holding on the slope" is adjusted to achieve "final holding on the slope". Exemplarily, the adjustment can be based on observing the vehicle speed change rate during the deceleration and holding on the slope process.

[0064] For example, the size of the vehicle speed change rate can be measured by setting a threshold value or a threshold range corresponding to the vehicle speed change rate, so as to facilitate the determination of the corresponding torque change amount and the corresponding torque gradient.

[0065] For example, the torque change and torque gradient can be obtained by looking up a table by establishing a table; different vehicle speed change rates in the table can correspond to the same or different torque changes and torque gradients; the data in the table can be obtained through experimental data or calculation methods.

[0066] Step S103: Correcting the initial value of the hill-holding torque based on the torque gradient and the torque variation to obtain at least one hill-holding torque target value.

[0067] As mentioned above, considering factors such as possible errors in the initial value of the hill-holding torque, the torque gradient and torque variation obtained in the above steps can be used to correct the initial value of the hill-holding torque, so as to obtain a hill-holding torque target value that better meets the actual hill-holding requirements of the vehicle.

[0068] The number of target values ​​of the hill-holding torque is related to the specific torque variation and torque gradient, and may not be limited to one. For example, if the initial value of the hill-holding torque is 100 Nm, the torque variation is 100 Nm, and the torque gradient is 50%, then there may be two target values ​​of the hill-holding torque, including 150 Nm and 200 Nm.

[0069] In one embodiment, the vehicle control unit (VCU) can obtain the vehicle speed change rate in real time or periodically, and then determine the corresponding torque change amount and torque gradient according to the actual situation of the vehicle speed change rate. For example, during the vehicle parking process, the vehicle may have multiple different vehicle speed change rates, and the multiple different vehicle speed change rates can correspond to multiple groups of different torque change amounts and torque gradients, and then correspond to multiple different parking torque target values.

[0070] Step S104: adjusting the torque output of the vehicle motor to a target hill-holding torque value to enable the vehicle to hold the vehicle on the hill.

[0071] In this embodiment, when the motor hill-holding function of the vehicle is activated, the initial value of the hill-holding torque is first determined to control the vehicle's deceleration and hill-holding; and the corresponding torque change and torque gradient are determined according to the speed change rate during the deceleration and hill-holding process, and the initial value of the hill-holding torque is corrected by the torque change and torque gradient to obtain the hill-holding torque target value, so that the hill-holding torque target value can meet the actual hill-holding demand of the vehicle; and the hill-holding torque target value is used to achieve the vehicle's hill-holding. That is, the vehicle is first decelerated and held on the hill, and adjustments are made according to the actual situation of the vehicle's deceleration and hill-holding to achieve precise hill-holding. This can avoid the situation where the initial value of the hill-holding torque has errors and cannot match the actual hill-holding demand of the vehicle, which affects the accuracy of the vehicle's hill-holding. At the same time, it can achieve the vehicle's hill-holding in the case of vehicle brake failure, thereby ensuring driving safety.

[0072] In one of the embodiments, the "obtaining the corresponding torque gradient based on the vehicle speed change rate" in the aforementioned embodiment may include: when the absolute value of the vehicle speed change rate is greater than a preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is a first torque gradient; when the absolute value of the vehicle speed change rate is less than the preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is a second torque gradient or a third torque gradient; when the absolute value of the vehicle speed change rate is within the preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is a fourth torque gradient; wherein the second torque gradient or the third torque gradient is less than the first torque gradient and greater than the fourth torque gradient.

[0073] For example, different torque gradients may be determined according to different vehicle speed change rates.

[0074] For example, a threshold range for the vehicle speed change rate can be preset to measure the vehicle's hill-holding effect and / or driving safety under the action of the initial value of the hill-holding torque, so that the corresponding torque gradient size can be determined based on the measured results, thereby achieving real-time feedback adjustment of the vehicle's hill-holding.

[0075] For example, when the absolute value of the vehicle speed change rate is greater than a preset threshold range, it means that the vehicle speed changes too much under the action of the initial value of the hill-holding torque, and the corresponding actual driving situation may be more dangerous, requiring a rapid and substantial adjustment of the hill-holding torque output by the vehicle's motor, so the corresponding torque gradient can be larger.

[0076] For example, when the absolute value of the vehicle speed change rate is within the preset threshold range, it means that the vehicle speed change under the action of the initial value of the hill-holding torque is within expectations, and the corresponding actual driving situation may be less dangerous. It is necessary to fine-tune the hill-holding torque output by the vehicle motor to achieve more accurate hill-holding.

[0077] For example, when the absolute value of the vehicle speed change rate is less than the preset threshold range, it means that the vehicle speed changes too little under the action of the initial value of the hill-holding torque, which may cause the vehicle to slip, especially when the vehicle's brake system fails, which is very dangerous. Therefore, the corresponding torque gradient can be large, so as to quickly and significantly adjust the hill-holding torque output by the vehicle motor to prevent and deal with danger in time.

[0078] The above contents are explained below by way of examples. The data in the examples are only used to illustrate the principle and may not match the data required in the actual situation:

[0079] Assuming that the preset threshold range is [2, 6] m / s², the corresponding torque gradient can be:

[0080] If the vehicle speed change rate is -7m / s², then the corresponding torque gradient is the first torque gradient, such as 50Nm; if the vehicle speed change rate is -1m / s², then the corresponding torque gradient is the second torque gradient or the third torque gradient, such as 20Nm or 16Nm; if the vehicle speed change rate is -3m / s², then the corresponding torque gradient is the fourth torque gradient, such as 5Nm.

[0081] In this embodiment, different torque gradients, i.e., the first to fourth torque gradients, are determined according to the magnitude of the vehicle speed change rate compared to the preset threshold range during the deceleration and hill-holding process, wherein the second torque gradient or the third torque gradient is smaller than the first torque gradient and larger than the fourth torque gradient. This enables the use of torque gradients of different magnitudes to deal with dangerous situations such as excessive vehicle speed change rate and vehicle slipping according to the degree of danger during the deceleration and hill-holding process, thereby ensuring driving safety; when the absolute value of the vehicle speed change rate is within the preset threshold range, a smaller torque gradient is used to obtain a more accurate hill-holding torque target value, which helps to improve the accuracy of the vehicle hill-holding.

[0082] In one embodiment, the second torque gradient in the aforementioned embodiment is greater than the third torque gradient; Figure 2As shown, in the aforementioned embodiment, “when the absolute value of the vehicle speed change rate is less than a preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is the second torque gradient or the third torque gradient” may include steps S201 to S202:

[0083] Step S201: When the absolute value of the vehicle speed change rate is less than a preset threshold range, determine the road slope on which the vehicle is located.

[0084] Step S202: When the road slope indicates that the vehicle is on an uphill slope, the torque gradient corresponding to the vehicle speed change rate is determined to be the second torque gradient; when the road slope indicates that the vehicle is on a downhill slope, the torque gradient corresponding to the vehicle speed change rate is determined to be the third torque gradient.

[0085] Exemplarily, the road slope on which the vehicle is located may be determined to be a relatively rough slope. For example, it is sufficient to determine the positive and negative values ​​of the road slope. A positive value may represent an uphill slope, and a negative value may represent a downhill slope.

[0086] Exemplarily, when the absolute value of the vehicle speed change rate is less than the preset threshold range, it means that the vehicle speed changes too little under the action of the initial value of the hill-holding torque. In this regard, the corresponding degree of danger of the actual driving situation can be discussed separately according to whether the vehicle is on an uphill or downhill slope: when the vehicle is on an uphill slope, there may be a situation of sliding backward due to the small change in vehicle speed, so the corresponding degree of danger of the actual driving situation may be relatively large. To avoid sliding backward, the hill-holding torque output by the vehicle motor should be increased, and the corresponding torque gradient can be relatively large; when the vehicle is on a downhill slope, there may be a situation of sliding forward due to the small change in vehicle speed, but the degree of danger of sliding forward is smaller than that of sliding backward (similar to reversing). Therefore, the corresponding torque gradient can be smaller than the torque gradient corresponding to sliding backward, but should not be smaller than the torque gradient corresponding to the absolute value of the vehicle speed change rate being within the preset threshold range.

[0087] In this embodiment, when the absolute value of the vehicle speed change rate is less than the preset threshold range during the deceleration and hill-holding process, the uphill and downhill situations are distinguished, corresponding to the second torque gradient and the third torque gradient, which are less than the first torque gradient and greater than the fourth torque gradient. This can achieve the adoption of torque gradients of different sizes to deal with dangerous situations such as backward and forward sliding of the vehicle according to the degree of danger during the deceleration and hill-holding process, thereby ensuring driving safety.

[0088] In one of the embodiments, the "obtaining the corresponding torque change based on the vehicle speed change rate" in the aforementioned embodiment may include: obtaining the vehicle's total mass and wheel rolling radius; based on the vehicle speed change rate, the vehicle's total mass and the wheel rolling radius, determining the torque change required by the vehicle's motor.

[0089] A possible specific calculation formula for determining the torque change is provided below: Torque change = vehicle mass × vehicle speed change rate × wheel rolling radius.

[0090] In this embodiment, the torque change required by the vehicle motor is determined by the vehicle speed change rate, the vehicle mass and the wheel rolling radius to serve the subsequent steps of correcting the initial value of the hill-holding torque and determining the target value of the hill-holding torque.

[0091] In one of the embodiments, the "correcting the initial value of the hill-holding torque based on the torque gradient and the torque change to obtain at least one hill-holding torque target value" in the aforementioned embodiment may include: successively adjusting the initial value of the hill-holding torque according to the torque gradient until the cumulative adjustment amount reaches the torque change amount, thereby obtaining at least one hill-holding torque target value.

[0092] The following is an example to illustrate:

[0093] Assume that the initial value of the hill-holding torque is 20Nm, the torque change is 20Nm, and the torque gradient is 5Nm. Therefore, the initial value of the hill-holding torque can be adjusted by 5Nm each time, and the target value of the hill-holding torque can include 25Nm, 30Nm, 35Nm, 40Nm, etc. For another example, assuming that the torque gradient is 20Nm and the rest is the same as the previous example, then the target value of the hill-holding torque can include 40Nm.

[0094] In this embodiment, the initial value of the hill-holding torque is adjusted successively by means of the torque gradient until the cumulative adjustment amount reaches the torque change amount, thereby obtaining at least one hill-holding torque target value. This makes the process of adjusting the initial value of the hill-holding torque to the torque change amount smoother, thereby achieving accurate hill-holding while avoiding vehicle stuttering and ensuring that the vehicle stays on the hill smoothly.

[0095] In one of the embodiments, the "adjusting the initial value of the hill-holding torque according to the torque gradient in sequence" in the aforementioned embodiment may include: when the absolute value of the vehicle speed change rate is greater than the preset threshold range, gradually reducing the initial value of the hill-holding torque according to the first torque gradient; when the absolute value of the vehicle speed change rate is less than the preset threshold range, gradually increasing the initial value of the hill-holding torque according to the second torque gradient or the third torque gradient; when the absolute value of the vehicle speed change rate is within the preset threshold range, determining the upper and lower limit averages of the preset threshold range, and when the absolute value of the vehicle speed change rate is less than the upper and lower limit averages, gradually increasing the initial value of the hill-holding torque according to the fourth torque gradient; when the absolute value of the vehicle speed change rate is greater than the upper and lower limit averages, gradually reducing the initial value of the hill-holding torque according to the fourth torque gradient.

[0096] As mentioned above, the initial value of the hill-holding torque can be adjusted successively by the torque gradient. For example, the initial value of the hill-holding torque can be adjusted according to the size of the vehicle speed change rate compared with the preset threshold range and different torque gradients.

[0097] When the absolute value of the vehicle speed change rate is within the preset threshold range, the corresponding adjustment strategy can be determined by the average value of the upper and lower limits of the preset threshold range. The value of the torque gradient can be an absolute value without positive or negative characteristics, and can be determined to be positive or negative, or increase or decrease, based on the above-mentioned vehicle speed change rate relative to the preset threshold range and the average value of the upper and lower limits of the preset threshold range. The preset threshold range can be adjusted according to actual conditions, and there is no restriction here.

[0098] The following is an example to illustrate:

[0099] Assume that the initial value of the hill-holding torque is 100 Nm, the preset threshold range is [3, 7] m / s², and the average value of the upper and lower limits of the preset threshold range is 5 m / s². Then the corresponding adjustment strategy can be:

[0100] If the vehicle speed change rate is -8m / s², then the corresponding torque gradient is the first torque gradient, such as 50Nm, then the initial value of the hill-holding torque is adjusted by reducing 50Nm each time;

[0101] If the vehicle speed change rate is -2m / s², the corresponding torque gradient is the second torque gradient or the third torque gradient. For example, if the vehicle is in the uphill stage, the corresponding second torque gradient, such as 20Nm, can be used to adjust the initial value of the holding torque by increasing it by 20Nm each time; if the vehicle is in the downhill stage, the corresponding third torque gradient, such as 16Nm, can be used to adjust the initial value of the holding torque by increasing it by 16Nm each time;

[0102] If the vehicle speed change rate is -6 m / s², the corresponding torque gradient is the fourth torque gradient, such as 5 Nm. Since the middle value or average value corresponding to the preset threshold range [3, 7] m / s² is 5 m / s², and the absolute value of the vehicle speed change rate is greater than the average value, the initial value of the hill-holding torque is adjusted by reducing it by 5 Nm each time.

[0103] If the vehicle speed change rate is -4m / s², then the corresponding torque gradient is the fourth torque gradient, such as 5Nm. Since the middle value or average value corresponding to the preset threshold range [3, 7] m / s² is 5m / s², and the absolute value of the vehicle speed change rate is less than the average value, the initial value of the hill-holding torque is adjusted by increasing by 5Nm each time.

[0104] In this embodiment, based on the torque gradient, the initial value of the hill-holding torque can be corrected by determining whether it is positive or negative, or increasing or decreasing, according to the absolute value of the vehicle speed change rate relative to the preset threshold range and the average value of the upper and lower limits of the preset threshold range, thereby helping to obtain a more accurate hill-holding torque target value.

[0105] In one embodiment, if Figure 3 As shown, the “determining the initial value of the hill-holding torque” in the above embodiment may include steps S301 to S303:

[0106] Step S301: Determine the driving information of the vehicle.

[0107] The driving information may be information representing the driving condition of the vehicle, such as vehicle speed, throttle opening, etc.

[0108] Step S302: When the driving information meets the preset hill-holding condition, the motor torque value corresponding to the slope of the vehicle in the current cycle is recorded.

[0109] For example, the driving information can be used to determine whether the current situation of the vehicle meets the preset hill-holding condition. For example, the preset hill-holding condition may include a vehicle speed of less than 5 km / h, a throttle opening of less than 20%, etc. The current vehicle speed is 3 km / h and the throttle opening is 10%, so it can be considered that the driving information meets the preset hill-holding condition. The specific contents protected by the driving information and the preset hill-holding condition can be increased, decreased, modified, etc. according to actual needs.

[0110] For example, the information of the vehicle using the vehicle motor to park on a slope in the past time period can be recorded, and the information here can include the slope, the motor torque value, etc. For example, a recording cycle can be set, such as 1 week, and the number of cycles can be greater than or equal to 1.

[0111] In some possible embodiments, the vehicle for which the record is made here and the vehicle for which the initial value of the hill-holding torque is subsequently determined to decelerate and hold the vehicle on a hill can be the same vehicle, and of course can also be the same model or type of vehicle, etc. Exemplarily, to ensure the accuracy of the determined initial value of the hill-holding torque, the similarity between the vehicle for which the record is made here and the vehicle for which the initial value of the hill-holding torque is subsequently determined to decelerate and hold the vehicle on a hill can meet a preset similarity condition, for example, they have the same model of drive motor, tire width, wheelbase, etc.

[0112] For example, the recording here can be achieved through vehicle-cloud interaction to record in the cloud, or it can be recorded locally in the vehicle.

[0113] Step S303: Determine the initial value of the hill-holding torque according to the recorded motor torque values ​​within a preset number of cycles.

[0114] The recorded motor torque value may be the same as or similar to the determined initial value of the hill-holding torque.

[0115] Exemplarily, the initial value of the hill-holding torque may be determined by using the average value of the motor torque values ​​within a preset number of cycles recorded in the aforementioned steps.

[0116] In some possible embodiments, when the hill-holding condition corresponding to the recorded motor torque value is different from the current actual hill-holding condition of the vehicle, the hill-holding condition close to the actual hill-holding condition can be preferentially referred to. Of course, the corresponding motor torque value can also be corrected to obtain the initial value of the hill-holding torque.

[0117] For example, in the previous cycle, the corresponding motor torque value when the slope is 5.0 degrees is 50Nm, the corresponding motor torque value when the slope is 6.0 degrees is 60Nm, the corresponding motor torque value when the slope is 7.0 degrees is 70Nm, and the corresponding motor torque value when the slope is 8.0 degrees is 80Nm. However, the current slope of the vehicle is 7.5 degrees. In this case, the data at slopes of 6.0 degrees and 7.0 degrees can be used as reference. The corresponding initial value of the slope-holding torque can be (70+60) / 2=65Nm.

[0118] In this embodiment, by recording the situation of the vehicle using the motor to hold the hill within a preset period, that is, the motor torque value corresponding to the slope of the vehicle, and determining the initial value of the hill-holding torque based on the recorded motor torque value, a more accurate initial value of the hill-holding torque can be obtained, so that the deceleration hill-holding effect corresponding to the initial value of the hill-holding torque is better; at the same time, as the number of times the vehicle's motor is used to hold the hill increases, the accuracy of the determined initial value of the hill-holding torque continues to improve.

[0119] In an exemplary embodiment, Figure 4 As shown, a vehicle holding hill control method is provided, which uses electric braking, that is, using the vehicle motor to brake, to generate deceleration to slow down the vehicle or even stop it, thereby achieving vehicle holding hill. The method includes steps S401 to S408, which are as follows:

[0120] Step S401: The vehicle controller VCU monitors the vehicle status in real time. The vehicle status may include the vehicle motor speed n, gear position, longitudinal acceleration a, vehicle mass m, rolling radius r, and the maximum recovery torque available for the motor.

[0121] The longitudinal acceleration a may be different from the aforementioned vehicle speed change rate. For example, the longitudinal acceleration a may be measured by a sensor of the vehicle, and the vehicle speed change rate may be determined by calculating the vehicle speed relative to the ground.

[0122] Step S402: Calculate the vehicle speed based on the motor speed.

[0123] There is a corresponding relationship between the motor speed and the vehicle speed. Traditionally, the vehicle speed is calculated by the wheel speed, which is collected by the ESC controller. If a fault is sent, for example, the vehicle controller cannot obtain the signal, and the ESC (Electronic Stability Controller) cannot control the brakes, then the vehicle speed can be calculated by the motor speed first in this scenario to avoid the problem of being unable to determine the vehicle speed. The following is a possible formula for calculating the vehicle speed:

[0124] The basic principle is as follows:

[0125] , where V is the vehicle speed (km / h), r is the tire radius (m), and i is the speed ratio. is the conversion factor from rotational speed to vehicle speed, and n is the vehicle motor speed (rpm).

[0126] Step S403: Determine the vehicle driving direction V based on the motor speed Direction The basic principle is as follows:

[0127] The vehicle's driving direction is determined when any of the following conditions are met:

[0128] ① The vehicle speed is less than 5 km / h (this threshold can be set to other values ​​based on actual needs, but the driving direction is generally determined when the absolute value of the vehicle speed over the ground is small); ② The vehicle's driving direction changes;

[0129] The specific vehicle driving direction is divided into forward and reverse. In some possible embodiments, the driving direction of the vehicle can be determined by the positive and negative of the motor speed, that is, forward and reverse. For example, a positive motor speed can correspond to a forward driving direction, and a negative motor speed can correspond to a reverse driving direction. For example, when the motor speed is less than -50rpm and the driving direction is reverse, V Direction Equal to -1, when the motor speed is greater than 50rpm, the driving direction is forward, V Direction Equal to 1. Of course, the motor speed threshold here can also take other values. In order to ensure the accuracy of the judgment, the value is generally not close to 0.

[0130] Step S404: Calculate the vehicle speed relative to the ground based on the driving direction and the motor speed, which is used to determine whether the vehicle is driving in the reverse direction. The basic principle can be reflected by the following calculation formula:

[0131] V Ground =V×V Direction , where V Ground is the ground speed, V Direction The direction of vehicle travel.

[0132] Step S405: Determine whether the function flag is activated based on the button, throttle, and vehicle speed relative to the ground.

[0133] Among them, the button can be a physical button, for example, it can be similar to the emergency light button of the vehicle, or it can be a virtual button, such as a virtual button displayed on the vehicle display screen. In an embodiment of the present application, the button can be associated with the opening and closing of the motor hill-holding function. For example, when the driver presses the button, it indicates that the motor needs to be used for hill-holding, so the function flag corresponding to the motor hill-holding function is activated. Exemplarily, the button can also be the existing buttons of the vehicle, such as the wiper button, the emergency light button, etc.

[0134] This step corresponds to the "activation of the vehicle's motor hill-holding function" and other related contents in the aforementioned embodiment. The basic principle is as follows:

[0135] Function activation condition: If the driver frequently presses the button for more than the set time threshold of 1 second, it means that there is a need to decelerate. Of course, the activation condition can also be other conditions. For example, when the driver presses the button multiple times in a short period of time, such as pressing the emergency light button three times in a row, the flag of the motor holding function is activated.

[0136] Function exit condition: The driver steps on the accelerator opening greater than 20% or the ground speed is less than -5km / h. When the driver steps on the accelerator, it means that there is a need for acceleration. When the ground speed is less than -5km / h, it means that the vehicle has reversed acceleration. In order to avoid unexpected movement, the function needs to be forced to exit. Of course, the ground speed here can also take other values, such as -3km / h, etc., which are not restricted here; the same applies to the throttle opening, which will not be repeated.

[0137] Step S406: Calculate the initial value of the holding torque based on the vehicle speed relative to the ground and the slope. If the vehicle speed is low enough and the speed change rate is small enough, it is considered that the torque can keep the vehicle stationary in this state, and the driver does not need to calculate the torque to overcome the slope resistance at this slope during driving. The basic principle is as follows:

[0138] The rate of change of vehicle speed relative to the ground is calculated by taking the derivative of the vehicle speed relative to the ground. If all the following conditions are met, the initial value of the holding torque can be calculated:

[0139] ① The driver did not step on the accelerator and brake pedals;

[0140] ② The vehicle is in a stable state, for example, the tires are not slipping, and the vehicle is not moving sideways, etc.;

[0141] ③ The vehicle speed over the ground is within the threshold range and the absolute value of the rate of change of the vehicle speed over the ground is within the threshold range;

[0142] If the above conditions are met, the corresponding torque at the current slope is recorded, and the average value within the set period is calculated. For example, the initial value of the slope-holding torque can be determined using the average value.

[0143] For example, the principle of this step may be to determine the initial value of the holding torque by referring to the torque required for the vehicle to hold the hill under normal conditions in the past period of time. For example, the reference standard here may be that the slope and the vehicle speed are the same or within the same preset range.

[0144] For example, the vehicle motor may be controlled according to the determined initial value of the hill-holding torque to decelerate the vehicle and hold the vehicle on the hill.

[0145] This step corresponds to "determining the initial value of the hill-holding torque, and controlling the vehicle motor based on the initial value of the hill-holding torque to decelerate the vehicle and hold the hill" and other related content.

[0146] Step S407: Setting a self-learning mechanism based on the vehicle speed change rate. This step corresponds to "obtaining the vehicle speed change rate during the deceleration and hill-holding process, and obtaining the corresponding torque change amount and the corresponding torque gradient based on the vehicle speed change rate" and other related contents.

[0147] In order to avoid the risk of the vehicle sliding down the hill due to too small a holding torque, or the risk of the vehicle moving in the opposite direction due to too large a holding torque, a self-learning mechanism is established to set the upper and lower limits of the vehicle speed change rate.

[0148] For example, the hill-holding effect corresponding to the initial hill-holding torque value determined in the aforementioned steps may not be good, that is, it may not match the actual hill-holding requirement. In this regard, a self-learning mechanism can be established to dynamically adjust the torque value required for hill-holding using the motor, thereby achieving hill-holding.

[0149] The basic principle of this step is as follows: The self-learning mechanism is allowed to run if the following conditions are met:

[0150] ① When the vehicle speed over the ground is within the threshold range;

[0151] ② According to the relationship between the vehicle speed change rate and the preset upper and lower ranges, determine the corresponding hill-holding torque adjustment strategy.

[0152] When the vehicle speed change rate is positive, that is, the vehicle is accelerating, the corresponding actual situation may be that the initial value of the hill-holding torque is too small to counteract the gravity exerted on the vehicle on the slope. Therefore, gravity causes the vehicle to accelerate. At this time, the initial value of the hill-holding torque needs to be increased.

[0153] When the speed change rate is negative, the vehicle is decelerating, such as -4 m / s 2 , its absolute value is 4m / s 2 , the preset upper and lower range is [4m / s2 ,10m / s 2 ]; the comparison between the speed change rate and the upper and lower limits is based on absolute values; the descriptions of being higher or lower or larger or smaller are all based on absolute values. The following situations are discussed in detail:

[0154] First, if the absolute value of the vehicle speed change rate is lower than the lower limit, if the vehicle is on an uphill slope, there is a risk of sliding backward, and if the vehicle is on a downhill slope, there is a risk of sliding forward, and it is necessary to increase the initial value of the hill-holding torque.

[0155] Second, if the absolute value of the speed change rate is within the upper and lower limits, a slight adjustment is made. If it is higher than the average of the upper and lower limits, the speed change rate is too large, and the initial value of the holding torque needs to be reduced. If it is lower than the average of the upper and lower limits, the speed change rate is too small, and the initial value of the holding torque needs to be increased. For example, the upper limit is 10m / s 2 , lower limit 4m / s 2 , then the average value is 7m / s 2 .

[0156] Third, if the absolute value of the vehicle speed change rate is higher than the upper limit, it is considered that the absolute value of the vehicle speed change rate is too large, the deceleration is too fast, and the vehicle is at risk of reverse movement, so the initial value of the holding torque needs to be reduced. Exemplarily, the setting of the initial value of the holding torque is to provide a basic value. If the initial value of the holding torque is too small, the absolute value of the vehicle speed change rate should not be too large, because F=ma, F (the driving force of the vehicle) is small, then a (vehicle speed change rate) is small, and m is the vehicle load, that is, the mass of the vehicle.

[0157] ③ Establish a torque gradient based on the speed change rate during deceleration. The torque gradient is equal to the torque change rate:

[0158] First, if the absolute value of the vehicle speed change rate is higher than the upper limit, it is considered that the risk level of this situation is the highest and the initial value needs to be reduced immediately, then the torque gradient is the largest;

[0159] Second, if the absolute value of the vehicle speed change rate is within the upper and lower limits, it is considered that the risk level of this situation is the lowest, and a smaller torque gradient can be set to just overcome the slope resistance;

[0160] Third, if the absolute value of the vehicle speed change rate is lower than the lower limit, it is considered that the situation has a certain degree of risk, and the torque gradient can be appropriately increased. The situation needs to take the slope factor into consideration. If the vehicle is on an uphill slope, the vehicle will slide backward. In this situation, the torque gradient should be greater than the situation where the vehicle is on a downhill slope and slides forward. For example, sliding backward, similar to reversing, is more dangerous than sliding forward. A large torque gradient is intended to control the torque within a reasonable range. A large torque gradient is not allowed only for uphill safety, but a large torque gradient is required to control uphill unsafe conditions, thereby avoiding sliding backward.

[0161] Regarding the torque variation The following is a possible calculation formula: , where a is the rate of change of vehicle speed (m / s 2 ), m is the load (kg), r is the rolling radius (m).

[0162] The torque variation is superimposed on the initial value by setting different torque gradients.

[0163] Step S408: Calculate the hill-holding torque target value based on the initial value, the self-learning torque gradient and the torque change, and control the torque output of the vehicle motor according to the hill-holding torque target value to achieve the hill-holding of the vehicle.

[0164] The basic principle is as follows: the target value of the holding torque is equal to the initial value of the holding torque ± the self-learning torque gradient, and the output of the vehicle motor torque is controlled by at least one holding torque target value until the last holding torque target value is equal to the initial value of the holding torque ± the torque change, so that the vehicle can hold the hill. This corresponds to "correcting the initial value of the holding torque based on the torque gradient and the torque change to obtain at least one holding torque target value", and "adjusting the torque output of the vehicle motor to the holding torque target value to make the vehicle hold the hill" and other related contents.

[0165] For example, assuming that the initial value of the hill-holding torque is X, the self-learning torque gradient may include a torque gradient of 20% and a torque variation of Y, then the hill-holding torque target value = X + 20% Y, so the torque output of the vehicle motor can be adjusted to X + 20% Y to control the vehicle to stay on the hill. In addition to the hill-holding torque target value = X + 20% Y, there may also be several hill-holding torque target values ​​such as X + 40% Y, X + 60% Y, X + 80% Y, and X + 100% Y, so that the last hill-holding torque target value is equal to the sum of the initial value of the hill-holding torque and the torque variation.

[0166] In this embodiment, the torque required for the current slope is determined by recording the speed change rate during the deceleration process, that is, the torque at low speed and low speed change rate in the past is identified as the initial value of the slope-holding torque, so that when the vehicle's slope-holding control function is activated, the risk of slipping or reverse movement caused by inaccurate torque is avoided. At the same time, a self-learning mechanism is set based on the speed change rate, and the slope-holding torque target value is calculated by limiting the torque gradient. According to the speed change rate, the corresponding torque gradient and torque change amount are determined, so as to determine the slope-holding torque target value, and form a "feedback adjustment" between the speed change rate and the torque gradient, and a "feedback adjustment" between the speed change rate and the torque change amount, so as to control the speed change rate within a certain range. Through this solution, the accuracy of the vehicle's slope holding can be improved and driving safety can be ensured.

[0167] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0168] Based on the same inventive concept, the embodiment of the present application also provides a vehicle holding hill control device for implementing the vehicle holding hill control method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more embodiments of the vehicle holding hill control device provided below can refer to the limitations of the vehicle holding hill control method above, and will not be repeated here.

[0169] In an exemplary embodiment, Figure 5 As shown, a vehicle hill-holding control device 500 is provided, comprising:

[0170] The first hill-holding module 501 is used to determine the initial value of the hill-holding torque when the hill-holding function of the motor of the vehicle is activated, and control the vehicle motor based on the initial value of the hill-holding torque to decelerate the vehicle and hold the vehicle on the hill;

[0171] The determination module 502 is used to obtain the vehicle speed change rate of the vehicle during the deceleration and hill-holding process, and obtain the corresponding torque change amount and the corresponding torque gradient based on the vehicle speed change rate; correct the initial hill-holding torque value based on the torque gradient and the torque change amount to obtain at least one hill-holding torque target value;

[0172] The second hill-holding module 503 is used to adjust the torque output of the vehicle motor to a hill-holding torque target value so as to enable the vehicle to stay on the hill.

[0173] In this embodiment, the first hill-holding module of the vehicle hill-holding control device determines the initial hill-holding torque value to control the vehicle to decelerate and hold the hill when the motor hill-holding function is activated; the determination module of the vehicle hill-holding control device determines the corresponding torque change and torque gradient according to the vehicle speed change rate during the deceleration and hill-holding process, and corrects the initial hill-holding torque value by the torque change and torque gradient to obtain the hill-holding torque target value, so that the hill-holding torque target value can meet the actual hill-holding demand of the vehicle; therefore, the second hill-holding module of the vehicle hill-holding control device realizes the vehicle hill-holding according to the hill-holding torque target value, which can realize more accurate hill-holding of the vehicle and avoid affecting the accuracy of the vehicle hill-holding due to errors in the initial hill-holding torque value and failure to match the actual hill-holding demand of the vehicle. At the same time, it can realize the vehicle hill-holding when the vehicle brakes fail, thereby ensuring driving safety.

[0174] In one embodiment, the determination module 502 is also used to obtain the corresponding torque gradient based on the vehicle speed change rate, including: when the absolute value of the vehicle speed change rate is greater than a preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is a first torque gradient; when the absolute value of the vehicle speed change rate is less than the preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is a second torque gradient or a third torque gradient; when the absolute value of the vehicle speed change rate is within the preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is a fourth torque gradient; wherein the second torque gradient or the third torque gradient is less than the first torque gradient and greater than the fourth torque gradient.

[0175] In one embodiment, the second torque gradient is greater than the third torque gradient; the determination module 502 is further configured to determine that the torque gradient corresponding to the vehicle speed change rate is the second torque gradient or the third torque gradient when the absolute value of the vehicle speed change rate is less than a preset threshold range, including:

[0176] When the absolute value of the vehicle speed change rate is less than a preset threshold range, determining the road slope on which the vehicle is located;

[0177] When the road slope indicates that the vehicle is on an uphill slope, the torque gradient corresponding to the vehicle speed change rate is determined to be the second torque gradient; when the road slope indicates that the vehicle is on a downhill slope, the torque gradient corresponding to the vehicle speed change rate is determined to be the third torque gradient.

[0178] In one embodiment, the determination module 502 is also used to obtain the corresponding torque change based on the vehicle speed change rate, including: obtaining the vehicle mass and wheel rolling radius of the vehicle; based on the vehicle speed change rate, the vehicle mass and the wheel rolling radius, determining the torque change required by the vehicle motor.

[0179] In one embodiment, the determination module 502 is further used to correct the initial value of the hill-holding torque based on the torque gradient and the torque change to obtain at least one hill-holding torque target value, including: successively adjusting the initial value of the hill-holding torque according to the torque gradient until the cumulative adjustment amount reaches the torque change amount, thereby obtaining at least one hill-holding torque target value.

[0180] In one embodiment, the determination module 502 is further configured to adjust the initial value of the hill-holding torque in sequence according to the torque gradient, including:

[0181] When the absolute value of the vehicle speed change rate is greater than a preset threshold range, the initial value of the hill-holding torque is gradually reduced according to the first torque gradient;

[0182] When the absolute value of the vehicle speed change rate is less than a preset threshold range, the initial value of the hill-holding torque is gradually increased according to the second torque gradient or the third torque gradient;

[0183] When the absolute value of the vehicle speed change rate is within the preset threshold range, the upper and lower limit averages of the preset threshold range are determined; when the absolute value of the vehicle speed change rate is less than the upper and lower limit averages, the initial value of the hill-holding torque is gradually increased according to the fourth torque gradient; when the absolute value of the vehicle speed change rate is greater than the upper and lower limit averages, the initial value of the hill-holding torque is gradually reduced according to the fourth torque gradient.

[0184] In one of the embodiments, the first hill-holding module 501 is also used to determine the initial value of the hill-holding torque, including: determining the driving information of the vehicle; when the driving information meets the preset hill-holding condition, recording the motor torque value corresponding to the slope of the vehicle in the current cycle; and determining the initial value of the hill-holding torque based on the recorded motor torque values ​​within the preset cycles.

[0185] Each module in the above-mentioned vehicle holding hill control device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0186] In an exemplary embodiment, a new energy vehicle is provided, and its internal structure diagram can be as follows: Figure 6As shown. The new energy vehicle includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the new energy vehicle is used to provide computing and control capabilities. The memory of the new energy vehicle includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the new energy vehicle is used to store data required for executing the vehicle holding hill control method, for example, the initial value of the holding hill torque. The input / output interface of the new energy vehicle is used to exchange information between the processor and an external device. The communication interface of the new energy vehicle is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a vehicle holding hill control method is implemented.

[0187] Those skilled in the art will understand that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the scheme of the present application, and does not constitute a limitation on the new energy vehicle to which the scheme of the present application is applied. A specific new energy vehicle may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0188] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0189] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0190] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0191] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0192] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0193] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A vehicle holding hill control method, characterized in that: The method comprises: When the motor holding hill function of the vehicle is activated, determining an initial value of the holding hill torque, and controlling the vehicle motor based on the initial value of the holding hill torque to decelerate the vehicle and hold the vehicle on the hill; During the deceleration and hill-holding process, a speed change rate of the vehicle is obtained, and a corresponding torque change amount and a corresponding torque gradient are obtained based on the speed change rate; The initial value of the hill-holding torque is corrected based on the torque gradient and the torque variation to obtain at least one hill-holding torque target value; The torque output of the vehicle motor is adjusted to the hill-holding torque target value so that the vehicle can stay on the hill.

2. The method according to claim 1, characterized in that The obtaining the corresponding torque gradient based on the vehicle speed change rate includes: When the absolute value of the vehicle speed change rate is greater than a preset threshold range, determining the torque gradient corresponding to the vehicle speed change rate as a first torque gradient; When the absolute value of the vehicle speed change rate is less than the preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is the second torque gradient or the third torque gradient; When the absolute value of the vehicle speed change rate is within the preset threshold range, determining the torque gradient corresponding to the vehicle speed change rate as a fourth torque gradient; The second torque gradient or the third torque gradient is smaller than the first torque gradient and larger than the fourth torque gradient.

3. The method according to claim 2, characterized in that The second torque gradient is greater than the third torque gradient; and when the absolute value of the vehicle speed change rate is less than the preset threshold range, determining that the torque gradient corresponding to the vehicle speed change rate is the second torque gradient or the third torque gradient includes: When the absolute value of the vehicle speed change rate is less than the preset threshold range, determining the road slope on which the vehicle is located; When the road slope indicates that the vehicle is on an uphill slope, determining a torque gradient corresponding to the vehicle speed change rate as the second torque gradient; When the road slope indicates that the vehicle is on a downhill slope, a torque gradient corresponding to the vehicle speed change rate is determined as the third torque gradient.

4. The method according to claim 2, characterized in that: The obtaining the corresponding torque change amount based on the vehicle speed change rate includes: Obtaining the vehicle mass and wheel rolling radius of the vehicle; The torque change required by the vehicle motor is determined based on the vehicle speed change rate, the vehicle mass, and the wheel rolling radius.

5. The method according to claim 4, characterized in that The step of correcting the initial value of the hill-holding torque based on the torque gradient and the torque variation to obtain at least one hill-holding torque target value includes: The initial value of the hill-holding torque is adjusted successively according to the torque gradient until the cumulative adjustment amount reaches the torque change amount, thereby obtaining at least one target value of the hill-holding torque.

6. The method according to claim 5, characterized in that The step of successively adjusting the initial value of the hill-holding torque according to the torque gradient comprises: When the absolute value of the vehicle speed change rate is greater than a preset threshold range, gradually reducing the initial value of the hill-holding torque according to the first torque gradient; When the absolute value of the vehicle speed change rate is less than the preset threshold range, gradually increasing the initial value of the hill-holding torque according to the second torque gradient or the third torque gradient; When the absolute value of the vehicle speed change rate is within the preset threshold range, the upper and lower limit average values ​​of the preset threshold range are determined; when the absolute value of the vehicle speed change rate is less than the upper and lower limit average values, the initial value of the hill-holding torque is gradually increased according to the fourth torque gradient; when the absolute value of the vehicle speed change rate is greater than the upper and lower limit average values, the initial value of the hill-holding torque is gradually reduced according to the fourth torque gradient.

7. The method according to any one of claims 1 to 6, characterized in that: The step of determining the initial value of the hill-holding torque comprises: Determining driving information of the vehicle; When the driving information satisfies the preset hill-holding condition, the motor torque value corresponding to the slope of the vehicle in the current cycle is recorded; The initial value of the hill-holding torque is determined according to the recorded motor torque values ​​within a preset number of cycles.

8. A vehicle holding hill control device, characterized in that: The device comprises: A first hill-holding module, configured to determine an initial hill-holding torque value when a hill-holding function of a motor of the vehicle is activated, and control a motor of the vehicle based on the initial hill-holding torque value to decelerate the vehicle and hold the vehicle on the hill; a determination module, configured to obtain a speed change rate of the vehicle during a deceleration and hill-holding process, and obtain a corresponding torque change amount and a corresponding torque gradient based on the speed change rate; and to correct the hill-holding torque initial value based on the torque gradient and the torque change amount to obtain at least one hill-holding torque target value; The second hill-holding module is used to adjust the torque output of the vehicle motor to the hill-holding torque target value so that the vehicle can stay on the hill.

9. A new energy vehicle, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images