Electric vehicle creeping control method and device

Abstract

The present invention discloses a method and device for controlling electric vehicle creeping, wherein the method comprises obtaining real-time creeping parameters of the vehicle, wherein the real-time creeping parameters at least include real-time vehicle speed, target vehicle speed, gear signal, longitudinal acceleration, ramp resistance distance, ramp holding torque and creeping output torque; according to the difference between the real-time vehicle speed and the target vehicle speed, PI adjustment is performed on the output torque of the vehicle motor; based on the PI-regulated output torque, real-time vehicle speed, target vehicle speed, gear signal, longitudinal acceleration and ramp resistance distance, the real-time working condition corresponding to the vehicle is identified; according to the real-time working condition, the real-time creeping parameters related to the real-time working condition are pre-processed. The method and device for controlling electric vehicle creeping provided by the embodiment of the present invention can solve the problems of the vehicle slipping when starting uphill, the uneven starting when starting downhill and the vehicle having a forward rushing feeling when starting after frequent release of the brake, thereby enhancing the starting performance of the vehicle creeping function and improving the driving quality of the vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle control, and in particular to a method and device for controlling creeping of an electric vehicle. Background Art

[0002] An electric vehicle is a vehicle that uses electricity as all or part of its power, meets road safety standards, and uses an electric motor to drive its wheels. With the continuous development of new energy technologies, the performance of electric vehicles is also constantly improving. Nowadays, electric vehicles are gradually recognized by the market and favored by consumers for their many advantages such as fast starting, zero emissions, low noise, and low energy consumption.

[0003] The creeping function of an electric vehicle can realize many functions such as parking on a slope, starting on a slope, and following a vehicle in congested road conditions. Nowadays, in the creeping control of electric vehicles, the control under uphill creeping starting conditions is to compensate for the torque by calculating the slope resistance distance. However, the calculation of the slope resistance distance by the prior art is inaccurate, and the vehicle will still slide down the slope. In addition, the prior art also does not take into account the forward rush problem caused by the vehicle in the process of creeping starting on a downhill slope, and the vehicle starting process after frequently releasing the brake in congested road conditions. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide an electric vehicle creeping control method and device, which can effectively solve the deficiencies of the prior art, optimize the vehicle's creeping performance, and thus improve the driving quality.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides an electric vehicle creep control method, comprising:

[0006] Acquiring real-time creep parameters of the vehicle, wherein the real-time creep parameters at least include real-time vehicle speed, target vehicle speed, gear position signal, longitudinal acceleration, ramp resistance distance, ramp holding torque and creep output torque;

[0007] According to the difference between the real-time vehicle speed and the target vehicle speed, PI adjustment is performed on the output torque of the vehicle motor;

[0008] Identifying a real-time operating condition corresponding to the vehicle based on the PI-regulated output torque, the real-time vehicle speed, the target vehicle speed, the gear position signal, the longitudinal acceleration, and the ramp resistance distance;

[0009] The real-time creep parameter related to the real-time operating condition is processed in a predetermined manner according to the real-time operating condition.

[0010] As one preferred solution, the real-time operating conditions at least include: an uphill starting condition, an integral torque correction condition, a downhill starting condition and a stop integral torque condition.

[0011] As one of the preferred solutions, when the vehicle is stationary on a slope, the gear signal is the D gear, the longitudinal acceleration is greater than zero, and the output torque adjusted by the PI is less than the slope resistance distance, the real-time operating condition corresponding to the vehicle is identified as the uphill starting condition;

[0012] When the output torque adjusted by the PI is greater than the ramp resistance distance, identifying the real-time operating condition corresponding to the vehicle as the integral torque correction operating condition;

[0013] When the vehicle is stationary on a slope, the gear signal is the D gear, and the longitudinal acceleration is less than zero, or when the vehicle is stationary on a slope, the gear signal is the R gear, and the longitudinal acceleration is greater than zero, identifying that the real-time operating condition corresponding to the vehicle is the downhill starting operating condition;

[0014] When the target vehicle speed is greater than the real-time vehicle speed, the real-time operating condition corresponding to the vehicle is identified as the stop integral torque operating condition.

[0015] As one of the preferred solutions, the real-time creep parameter related to the real-time working condition is predetermined according to the real-time working condition, specifically:

[0016] When it is identified that the vehicle is in the uphill starting condition, the proportional regulation in the PI regulation is turned off, and the ramp resistance distance is corrected by integral regulation;

[0017] When it is identified that the vehicle is in the integral torque correction operating condition, reducing the PI output torque and correcting the ramp holding torque;

[0018] When it is identified that the vehicle is in the downhill starting condition, the proportional regulation in the PI regulation is turned off, and the creep output torque is corrected by integral regulation;

[0019] When it is identified that the vehicle is in the stop integral condition, the integral regulation in the PI regulation is turned off, and the creep output torque is corrected through proportional regulation.

[0020] As one of the preferred solutions, the ramp resistance distance is obtained based on a preset ramp resistance distance relationship;

[0021] The slope resistance distance relationship is:

[0022] T f =m*a*r

[0023] Among them, T f is the ramp resistance distance, m is the vehicle reference mass, a is the longitudinal acceleration, and r is the tire rolling radius.

[0024] Another embodiment of the present invention provides an electric vehicle creep control device, including a controller, wherein the controller is configured as follows:

[0025] Acquiring real-time creep parameters of the vehicle, wherein the real-time creep parameters at least include real-time vehicle speed, target vehicle speed, gear position signal, longitudinal acceleration, ramp resistance distance, ramp holding torque and creep output torque;

[0026] According to the difference between the real-time vehicle speed and the target vehicle speed, PI adjustment is performed on the output torque of the vehicle motor;

[0027] Identifying a real-time operating condition corresponding to the vehicle based on the PI-regulated output torque, the real-time vehicle speed, the target vehicle speed, the gear position signal, the longitudinal acceleration, and the ramp resistance distance;

[0028] The real-time creep parameter related to the real-time operating condition is processed in a predetermined manner according to the real-time operating condition.

[0029] As one preferred solution, the real-time operating conditions at least include: an uphill starting condition, an integral torque correction condition, a downhill starting condition and a stop integral torque condition.

[0030] As one preferred solution, the controller is configured as follows:

[0031] When the vehicle is stationary on a slope, the gear position signal is the D gear, the longitudinal acceleration is greater than zero, and the output torque adjusted by the PI is less than the slope resistance distance, identifying the real-time operating condition corresponding to the vehicle as the uphill starting operating condition;

[0032] When the output torque adjusted by the PI is greater than the ramp resistance distance, identifying the real-time operating condition corresponding to the vehicle as the integral torque correction operating condition;

[0033] When the vehicle is stationary on a slope, the gear signal is the D gear, and the longitudinal acceleration is less than zero, or when the vehicle is stationary on a slope, the gear signal is the R gear, and the longitudinal acceleration is greater than zero, identifying that the real-time operating condition corresponding to the vehicle is the downhill starting operating condition;

[0034] When the target vehicle speed is greater than the real-time vehicle speed, the real-time operating condition corresponding to the vehicle is identified as the stop integral torque operating condition.

[0035] As one preferred solution, the controller is configured as follows:

[0036] When it is identified that the vehicle is in the uphill starting condition, the proportional regulation in the PI regulation is turned off, and the ramp resistance distance is corrected by integral regulation;

[0037] When it is identified that the vehicle is in the integral torque correction operating condition, reducing the PI output torque and correcting the ramp holding torque;

[0038] When it is identified that the vehicle is in the downhill starting condition, the proportional regulation in the PI regulation is turned off, and the creep output torque is corrected by integral regulation;

[0039] When it is identified that the vehicle is in the stop integral condition, the integral regulation in the PI regulation is turned off, and the creep output torque is corrected through proportional regulation.

[0040] As one of the preferred solutions, the ramp resistance distance is obtained based on a preset ramp resistance distance relationship;

[0041] The slope resistance distance relationship is:

[0042] T f =m*a*r

[0043] Among them, T f is the ramp resistance distance, m is the vehicle reference mass, a is the longitudinal acceleration, and r is the tire rolling radius.

[0044] Compared with the prior art, the beneficial effects of the embodiments of the present invention lie in at least one of the following: by first acquiring the real-time crawling parameters of the vehicle, data support is provided for the subsequent control method; then the output torque of the vehicle motor is PI-regulated. Due to the different crawling working conditions, it is necessary to first determine the different crawling working conditions, and then perform predetermined processing on the different crawling working conditions in a targeted manner. Among them, the present invention identifies the working condition for the problem of the vehicle sliding downhill when starting from a crawling uphill slope, and then performs specific PI regulation to dynamically coordinate the crawling torque to ensure that the vehicle does not slide downhill when starting from a crawling uphill slope; for the problem of uneven starting, the working condition is identified, and then a specific PI regulation is performed to reduce the crawling torque output and avoid the uneven feeling of starting downhill due to the slope force component; for the problem of the forward rush at the start after frequent release of the brake, the working condition is identified, and then a specific PI regulation is performed to reduce the accumulation of integral errors, optimize PI control, and solve the forward rush problem at the start. It can be seen that the electric vehicle crawling control method provided by the present invention can solve three specific problems of slipping when starting uphill, uneven starting downhill, and a forward rushing feeling when the vehicle starts after frequently releasing the brake, thereby enhancing the starting performance of the vehicle's crawling function and improving the vehicle's driving quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flow chart of a creep control method for an electric vehicle in one embodiment of the present invention;

[0046] Figure 2is a flow chart of a torque control method for starting on a slope in one embodiment of the present invention;

[0047] Figure 3 is a flow chart of a torque control method for downhill starting condition in one embodiment of the present invention;

[0048] Figure 4 It is a flow chart of a torque control method under stop integral condition in one embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0051] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0052] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0053] An embodiment of the present invention provides a method for controlling creeping of an electric vehicle. For details, see Figure 1 , Figure 1The flowchart of the electric vehicle creep control method in one embodiment of the present invention is shown, which includes:

[0054] S101, obtaining real-time creeping parameters of the vehicle, wherein the real-time creeping parameters at least include real-time vehicle speed, target vehicle speed, gear signal, longitudinal acceleration, ramp resistance distance, ramp holding torque and creeping output torque;

[0055] S102, performing PI adjustment on the output torque of the vehicle motor according to the difference between the real-time vehicle speed and the target vehicle speed;

[0056] S103, identifying a real-time operating condition corresponding to the vehicle based on the PI-regulated output torque, the real-time vehicle speed, the target vehicle speed, the gear position signal, the longitudinal acceleration, and the ramp resistance distance;

[0057] S104. Perform predetermined processing on the real-time creeping parameters related to the real-time operating condition according to the real-time operating condition.

[0058] It should be noted that the electric vehicle creep control method provided by the embodiment of the present invention identifies the uphill start condition, the integral torque correction condition, the stop integral torque condition and the downhill start condition according to the motor speed, the vehicle longitudinal acceleration, the driving gear and the creep target speed, so that the subsequent vehicle can correct the motor output torque through the four creep function conditions, which greatly improves the vehicle creep start performance. Among them, for the control of the uphill creep start condition, the prior art is to calculate the slope resistance torque to compensate the creep torque. Generally, the slope is estimated by the longitudinal acceleration sensor of the whole vehicle or the slope sensor is directly installed to obtain the slope, and the component torque of the whole vehicle mass along the slope is calculated, which is the slope resistance torque. However, on the one hand, the acceleration sensor or the slope sensor is easily affected by external interference and has low robustness; on the other hand, the number of passengers on the vehicle directly affects the whole vehicle mass, and then affects the accuracy of the slope resistance torque estimation. It can be seen that the prior art is inaccurate in estimating the slope resistance torque, and the motor output torque is lagging, which will cause the vehicle to slip when creeping. The prior art does not consider the control of the vehicle's downhill crawling start condition, and the forward rush problem caused by the vehicle starting after frequently releasing the brakes in congested road conditions. Therefore, the purpose of the embodiments of the present invention is to provide an electric vehicle crawling control method, which can effectively solve the above-mentioned deficiencies of the prior art, optimize the vehicle's crawling performance, and thus improve the driving quality.

[0059] Further, in the above embodiment, the real-time operating condition at least includes: an uphill starting operating condition, an integral torque correction operating condition, a downhill starting operating condition and a stop integral torque operating condition.

[0060] First, in this embodiment, since the acceleration sensor is susceptible to external interference and changes in the weight of the vehicle, the ramp resistance torque required for holding the slope must be dynamically corrected. When the vehicle is holding the slope on an uphill slope, preferably, the ramp resistance torque required for holding the slope is calculated based on the longitudinal acceleration signal of the vehicle in a stationary state provided by the ESP system of the electric vehicle, and then the integral control is performed based on the difference between the crawling target speed and the real-time speed, and the holding torque output by the motor is dynamically coordinated to control the real-time speed to 0. When the vehicle starts on a slope, the current motor torque is directly output, avoiding the hysteresis problem of the motor output torque.

[0061] When the vehicle starts on a downhill slope, the gravity component torque along the slope interferes with the creep torque, causing the actual output creep torque of the motor to be uneven, which in turn causes the real-time vehicle speed to change unevenly. This problem can be solved by identifying the downhill starting condition and correcting the creep torque.

[0062] When a vehicle frequently releases the brakes in a traffic jam, the integral term in the PI control will continue to accumulate errors, resulting in a large creep torque being output when the brakes are finally released, causing a forward rush when starting. This problem can be solved by identifying this condition and correcting the creep torque.

[0063] Further, in the above embodiment, when the vehicle is stationary on a slope, the gear position signal is the D gear, the longitudinal acceleration is greater than zero, and the output torque adjusted by the PI is less than the slope resistance distance, the real-time operating condition corresponding to the vehicle is identified as the uphill starting operating condition;

[0064] When the output torque adjusted by the PI is greater than the ramp resistance distance, identifying the real-time operating condition corresponding to the vehicle as the integral torque correction operating condition;

[0065] When the vehicle is stationary on a slope, the gear signal is the D gear, and the longitudinal acceleration is less than zero, or when the vehicle is stationary on a slope, the gear signal is the R gear, and the longitudinal acceleration is greater than zero, identifying that the real-time operating condition corresponding to the vehicle is the downhill starting operating condition;

[0066] When the target vehicle speed is greater than the real-time vehicle speed, the real-time operating condition corresponding to the vehicle is identified as the stop integral torque operating condition.

[0067] Further, in the above embodiment, the real-time creep parameter related to the real-time working condition is predeterminedly processed according to the real-time working condition, specifically:

[0068] When it is identified that the vehicle is in the uphill starting condition, the proportional regulation in the PI regulation is turned off, and the ramp resistance distance is corrected by integral regulation;

[0069] When it is identified that the vehicle is in the integral torque correction working condition, reducing the PI output torque and correcting the ramp holding torque;

[0070] When it is identified that the vehicle is in the downhill starting condition, the proportional regulation in the PI regulation is turned off, and the creep output torque is corrected by integral regulation;

[0071] When it is identified that the vehicle is in the stop integral condition, the integral regulation in the PI regulation is turned off, and the creep output torque is corrected through proportional regulation.

[0072] The specific control logic of various working conditions is described below. For ease of understanding, the uphill start condition and the integral torque correction condition are described in the same control logic:

[0073] For details, see Figure 2 , Figure 2 FIG. 1 is a flow chart of a torque control method for starting on a ramp in one embodiment of the present invention. The torque control method for starting on a ramp in this embodiment includes:

[0074] S1. When the creeping function is activated, the vehicle is identified as being stationary based on the motor speed. Preferably, the vehicle is predicted to be stationary based on the motor speed, that is, when the motor speed is less than a certain value and maintained for a certain period of time, the vehicle can be determined to be stationary. The speed condition and time condition need to be calibrated on the actual vehicle.

[0075] S2: According to the judgment in step S1 that the vehicle is stationary, the longitudinal acceleration signal a sent by the ESP system is obtained through the CAN bus, and the ramp resistance torque T is calculated using the vehicle reference mass m and the tire rolling radius r. f , that is, T f =m*a*r;

[0076] S3, receiving the driving gear signal transmitted by CAN, when the gear is D gear, if the PI controller outputs torque T intg When the vehicle longitudinal acceleration is greater than zero and the motor speed is less than a certain value, it is a D gear uphill start condition. The proportional control in the PI controller is turned off, and the torque is dynamically corrected for the ramp resistance torque only through integral control.

[0077] It should be noted that the PI controller output torque T intg The difference with the ramp resistance torque is less than a certain value, which needs to be calibrated on the actual vehicle. Under the premise of achieving the target crawling speed, the crawling output torque will not continue to fluctuate. The uphill start condition only uses the integral control in the PI controller. The integral control parameter needs to be calibrated on the actual vehicle to achieve the target crawling speed.

[0078] S4. After the ramp resistance torque is dynamically corrected in step S3, if the PI controller outputs torque T intg If the slope resistance torque is greater than a certain value or the vehicle has started normally, exit the uphill start torque control; preferably, the PI controller outputs the torque T intg The difference with the ramp resistance torque is greater than a certain value. This value needs to be calibrated on the actual vehicle. Under the premise of achieving the crawling target speed, the crawling output torque will not fluctuate continuously.

[0079] S5. After exiting the torque control of the uphill start condition, when there is no crawling target speed and the vehicle does not start normally, determine the output torque T of the PI controller. intg Relationship with ramp resistance torque: If the PI controller outputs torque T intg If the integral torque is greater than a certain value of the ramp resistance torque, it is an integral torque overshoot, which is identified as an integral torque correction condition, and the output torque of the PI controller is reduced to dynamically control the ramp holding torque; preferably, the integral torque correction condition only uses the integral control in the PI controller, and the integral control parameters need to be calibrated by the actual vehicle, so that the integral torque overshoot does not occur, and the ramp holding torque is dynamically corrected;

[0080] S6. After exiting the torque control of the uphill start condition, when the crawling target speed is greater than 0 or the vehicle has started normally, the crawling target speed is adjusted to the crawling target speed through PI control;

[0081] S7, receiving the driving gear signal transmitted by CAN, when the gear is R gear, if the PI controller outputs torque T intg When the vehicle longitudinal acceleration is less than a certain value of the ramp resistance torque and the motor speed is greater than a certain value, it belongs to the uphill starting condition in R gear. The proportional control in the PI controller is turned off, and the ramp resistance torque is dynamically corrected by the integral control only.

[0082] For details, see Figure 3 , Figure 3 FIG. 1 is a flow chart of a torque control method for a downhill start condition in one embodiment of the present invention. The torque control method for a downhill start condition in this embodiment includes:

[0083] S8: When the creep function is activated, the vehicle is identified as stationary by the brake pedal depth and motor speed;

[0084] S9, receiving the driving gear position signal transmitted by CAN, when the gear position is D gear, when the longitudinal acceleration is less than 0, it is determined that the vehicle is stationary on the downhill slope; when the gear position is R gear, when the longitudinal acceleration is greater than 0, it is determined that the vehicle is stationary on the downhill slope;

[0085] S10, the brake pedal is released, and the vehicle has a crawling target speed, and it is determined to be a downhill start condition; preferably, a brake pedal depth less than a certain value can be understood as the brake pedal is released, and this certain value needs to be calibrated on the actual vehicle to avoid identifying the downhill start condition too early or too late, which affects the downhill start smoothness;

[0086] S11. According to steps S8 to S10, a downhill start condition is identified, and the PI controller does not perform proportional adjustment, but controls the creep output torque only through integral adjustment; preferably, the downhill start condition torque control only uses the integral control in the PI controller, and the integral control parameter needs to be calibrated by the actual vehicle to ensure that the real-time vehicle speed does not exceed the target vehicle speed, thereby ensuring the smoothness of the downhill start;

[0087] S12: When the crawling target vehicle speed exceeds the real-time vehicle speed, the downhill start is completed, and the downhill start condition torque control is exited;

[0088] S13. Target vehicle speed control is achieved through PI regulation. Under normal target vehicle speed control conditions, proportional control and integral control in PI control are used. Actual vehicle calibration is required to achieve target vehicle speed control.

[0089] For details, see Figure 4 , Figure 4 FIG. 1 is a flow chart of a torque control method for a stop integral condition in one embodiment of the present invention. The torque control method for a stop integral condition in this embodiment includes:

[0090] S14: When the creep function is activated, the real-time vehicle speed is less than the target vehicle speed and the real-time vehicle speed is greater than 0, and whether to enter the stop integral condition torque control is determined according to the difference between the target vehicle speed and the real-time vehicle speed and the growth rate of the real-time vehicle speed;

[0091] S15: If the target vehicle speed is greater than a certain value of the real-time vehicle speed and the real-time vehicle speed growth rate is greater than a certain value, it is determined to be a stop integration condition, and the PI controller does not perform integral adjustment to avoid error accumulation, which causes the vehicle to be uneven when starting with the brake released. At this time, the creep output torque is controlled only by proportional adjustment;

[0092] It should be noted that the difference between the target speed and the real-time speed directly affects the torque output of the PI controller, and needs to be calibrated on the actual vehicle to avoid abrupt starting. The growth rate of the real-time speed represents the subjective acceleration of the driver during the crawling process. If the growth rate is too large, the acceleration of the vehicle will be inconsistent during the entire crawling process. It needs to be calibrated on the actual vehicle to avoid identifying the stop integration condition too late, which will lead to inconsistent acceleration of the vehicle during the entire crawling process. For the torque control of the stop integration condition, only the proportional control in the PI controller is used. The proportional control parameters need to be calibrated on the actual vehicle to ensure consistent acceleration of the vehicle during the crawling process.

[0093] S16, when the real-time vehicle speed approaches the target vehicle speed or the real-time vehicle speed increases slowly, exit the stop integral working condition torque control; preferably, the real-time vehicle speed increases slowly, which means that the current creep torque achieves the expected vehicle acceleration feeling, and there is no need to perform the stop integral working condition correction;

[0094] S17. Realize target vehicle speed control through PI regulation.

[0095] Another embodiment of the present invention provides an electric vehicle creep control device, including a controller, wherein the controller is configured as follows:

[0096] Acquiring real-time creep parameters of the vehicle, wherein the real-time creep parameters at least include real-time vehicle speed, target vehicle speed, gear position signal, longitudinal acceleration, ramp resistance distance, ramp holding torque and creep output torque;

[0097] According to the difference between the real-time vehicle speed and the target vehicle speed, PI adjustment is performed on the output torque of the vehicle motor;

[0098] Identifying a real-time operating condition corresponding to the vehicle based on the PI-regulated output torque, the real-time vehicle speed, the target vehicle speed, the gear position signal, the longitudinal acceleration, and the ramp resistance distance;

[0099] The real-time creep parameter related to the real-time operating condition is processed in a predetermined manner according to the real-time operating condition.

[0100] Further, in the above embodiment, the real-time operating condition at least includes: an uphill starting operating condition, an integral torque correction operating condition, a downhill starting operating condition and a stop integral torque operating condition.

[0101] Furthermore, in the above embodiment, the controller is configured as follows:

[0102] When the vehicle is stationary on a slope, the gear position signal is the D gear, the longitudinal acceleration is greater than zero, and the output torque adjusted by the PI is less than the slope resistance distance, identifying the real-time operating condition corresponding to the vehicle as the uphill starting operating condition;

[0103] When the output torque adjusted by the PI is greater than the ramp resistance distance, identifying the real-time operating condition corresponding to the vehicle as the integral torque correction operating condition;

[0104] When the vehicle is stationary on a slope, the gear signal is the D gear, and the longitudinal acceleration is less than zero, or when the vehicle is stationary on a slope, the gear signal is the R gear, and the longitudinal acceleration is greater than zero, identifying that the real-time operating condition corresponding to the vehicle is the downhill starting operating condition;

[0105] When the target vehicle speed is greater than the real-time vehicle speed, the real-time operating condition corresponding to the vehicle is identified as the stop integral torque operating condition.

[0106] Furthermore, in the above embodiment, the controller is configured as follows:

[0107] When it is identified that the vehicle is in the uphill starting condition, the proportional regulation in the PI regulation is turned off, and the ramp resistance distance is corrected by integral regulation;

[0108] When it is identified that the vehicle is in the integral torque correction operating condition, reducing the PI output torque and correcting the ramp holding torque;

[0109] When it is identified that the vehicle is in the downhill starting condition, the proportional regulation in the PI regulation is turned off, and the creep output torque is corrected by integral regulation;

[0110] When it is identified that the vehicle is in the stop integral condition, the integral regulation in the PI regulation is turned off, and the creep output torque is corrected through proportional regulation.

[0111] Further, in the above embodiment, the ramp resistance distance is obtained based on a preset ramp resistance distance relationship;

[0112] The slope resistance distance relationship is:

[0113] T f =m*a*r

[0114] Among them, T f is the ramp resistance distance, m is the vehicle reference mass, a is the longitudinal acceleration, and r is the tire rolling radius.

[0115] The electric vehicle creep control method and device provided by the embodiment of the present invention have the beneficial effects of at least one of the following:

[0116] By first obtaining the real-time crawling parameters of the vehicle, data support is provided for the subsequent control method; then the output torque of the vehicle motor is PI-regulated. Due to the different working conditions of crawling, it is necessary to first determine different crawling working conditions, and then perform predetermined processing on different crawling working conditions in a targeted manner. Among them, the present invention identifies the working condition for the problem of the vehicle sliding downhill when starting from a crawling uphill, and then performs a specific PI adjustment to dynamically coordinate the crawling stationary torque to ensure that the crawling uphill start does not slide downhill; for the problem of uneven starting, the working condition is identified, and then a specific PI adjustment is performed to reduce the output of the crawling torque to avoid the uneven feeling of starting downhill due to the slope force component; for the problem of the forward rush feeling after frequent release of the brake, the working condition is identified, and then a specific PI adjustment is performed to reduce the accumulation of the integral error, optimize the PI control, and solve the problem of forward rush when starting. It can be seen that the electric vehicle crawling control method provided by the present invention can solve the three specific problems of sliding downhill when starting from a crawling uphill, uneven starting from a downhill, and the forward rush feeling of the vehicle after frequent release of the brake, thereby enhancing the starting performance of the vehicle crawling function and improving the driving quality of the vehicle.

[0117] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A creep control method for an electric vehicle, characterized in that: include: Acquiring real-time creep parameters of the vehicle, wherein the real-time creep parameters at least include real-time vehicle speed, target vehicle speed, gear position signal, longitudinal acceleration, ramp resistance torque, ramp holding torque and creep output torque; According to the difference between the real-time vehicle speed and the target vehicle speed, PI adjustment is performed on the output torque of the vehicle motor; Identifying a real-time operating condition corresponding to the vehicle based on the PI-regulated output torque, the real-time vehicle speed, the target vehicle speed, the gear position signal, the longitudinal acceleration, and the ramp resistance torque; The real-time creeping parameters related to the real-time operating condition are pre-processed according to the real-time operating condition; the real-time operating condition at least includes: uphill starting condition, integral torque correction condition, downhill starting condition and stop integral torque condition.

2. The electric vehicle creep control method according to claim 1, characterized in that: When the vehicle is stationary on a slope, the gear position signal is the D gear, the longitudinal acceleration is greater than zero, and the output torque adjusted by the PI is less than the slope resistance torque, identifying the real-time operating condition corresponding to the vehicle as the uphill starting operating condition; When the output torque adjusted by the PI is greater than the ramp resistance torque, identifying the real-time operating condition corresponding to the vehicle as the integral torque correction operating condition; When the vehicle is stationary on a slope, the gear signal is the D gear, and the longitudinal acceleration is less than zero, or when the vehicle is stationary on a slope, the gear signal is the R gear, and the longitudinal acceleration is greater than zero, identifying that the real-time operating condition corresponding to the vehicle is the downhill starting operating condition; When the target vehicle speed is greater than the real-time vehicle speed, the real-time operating condition corresponding to the vehicle is identified as the stop integral torque operating condition.

3. The electric vehicle creep control method according to claim 2, characterized in that: The predetermined processing of the real-time creep parameter related to the real-time working condition according to the real-time working condition is specifically: When it is identified that the vehicle is in the uphill starting condition, the proportional regulation in the PI regulation is turned off, and the slope resistance torque is corrected by integral regulation; When it is identified that the vehicle is in the integral torque correction operating condition, reducing the output torque of the PI regulation and correcting the ramp holding torque; When it is identified that the vehicle is in the downhill starting condition, the proportional regulation in the PI regulation is turned off, and the creep output torque is corrected by integral regulation; When it is identified that the vehicle is in the stop integral torque condition, the integral regulation in the PI regulation is turned off, and the creep output torque is corrected through proportional regulation.

4. The electric vehicle creep control method according to claim 1, characterized in that: Obtaining the ramp resistance torque based on a preset ramp resistance torque relationship; The ramp resistance torque relationship is: T f =m*a*r Among them, T f is the ramp resistance torque, m is the vehicle reference mass, a is the longitudinal acceleration, and r is the tire rolling radius.

5. An electric vehicle creeping control device, characterized in that: comprising a controller configured to: Acquiring real-time creep parameters of the vehicle, wherein the real-time creep parameters at least include real-time vehicle speed, target vehicle speed, gear position signal, longitudinal acceleration, ramp resistance torque, ramp holding torque and creep output torque; According to the difference between the real-time vehicle speed and the target vehicle speed, PI adjustment is performed on the output torque of the vehicle motor; Identifying a real-time operating condition corresponding to the vehicle based on the PI-regulated output torque, the real-time vehicle speed, the target vehicle speed, the gear position signal, the longitudinal acceleration, and the ramp resistance torque; The real-time creeping parameters related to the real-time operating condition are pre-processed according to the real-time operating condition; the real-time operating condition at least includes: uphill starting condition, integral torque correction condition, downhill starting condition and stop integral torque condition.

6. The electric vehicle creep control device according to claim 5, characterized in that: The controller is configured to: When the vehicle is stationary on a slope, the gear position signal is the D gear, the longitudinal acceleration is greater than zero, and the output torque adjusted by the PI is less than the slope resistance torque, identifying the real-time operating condition corresponding to the vehicle as the uphill starting operating condition; When the output torque adjusted by the PI is greater than the ramp resistance torque, identifying the real-time operating condition corresponding to the vehicle as the integral torque correction operating condition; When the vehicle is stationary on a slope, the gear signal is the D gear, and the longitudinal acceleration is less than zero, or when the vehicle is stationary on a slope, the gear signal is the R gear, and the longitudinal acceleration is greater than zero, identifying that the real-time operating condition corresponding to the vehicle is the downhill starting operating condition; When the target vehicle speed is greater than the real-time vehicle speed, the real-time operating condition corresponding to the vehicle is identified as the stop integral torque operating condition.

7. The electric vehicle creep control device according to claim 6, characterized in that: The controller is configured to: When it is identified that the vehicle is in the uphill starting condition, the proportional regulation in the PI regulation is turned off, and the slope resistance torque is corrected by integral regulation; When it is identified that the vehicle is in the integral torque correction operating condition, reducing the output torque of the PI regulation and correcting the ramp holding torque; When it is identified that the vehicle is in the downhill starting condition, the proportional regulation in the PI regulation is turned off, and the creep output torque is corrected by integral regulation; When it is identified that the vehicle is in the stop integral torque condition, the integral regulation in the PI regulation is turned off, and the creep output torque is corrected through proportional regulation.

8. The electric vehicle creep control device according to claim 5, characterized in that: Obtaining the ramp resistance torque based on a preset ramp resistance torque relationship; The ramp resistance torque relationship is: T f =m*a*r Among them, T f is the ramp resistance torque, m is the vehicle reference mass, a is the longitudinal acceleration, and r is the tire rolling radius.

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