Slope holding control method and equipment
By receiving the actual speed of the motor and calculating the feedforward torque, the existing vehicle slope control method has solved the problem of slow torque response and difficult calculation of precise slope torque, which has achieved fast response and accurate slope and improved driving experience.
Patent Information
- Application Number
- CN202311183961.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-12
- Publication Date
- 2025-03-14
AI Technical Summary
The existing vehicle slope control method has slow torque adjustment response, resulting in a long slip distance and lacks an accurate slope torque calculation scheme under different slopes and load conditions.
By receiving the actual rotation speed of the motor and determining the feedforward torque based on the difference between the actual rotation speed and the filtered rotation speed, the torque demand value is calculated to realize the vehicle's stopping. This method uses a first-order filter to smooth the speed signal, reduce errors, and adjust the torque demand value through the PI controller.
The torque response speed is accelerated, the distance of sliding is reduced, and the slope-stabilizing torque can be accurately calculated under different slopes and load conditions to ensure that the vehicle is normally sloped on the slope. At the same time, by gradually applying feedforward torque, the obvious forward rush of the vehicle is avoided and the driving experience is improved.
Smart Images
Figure CN119611082A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of hill-holding control, and more specifically, to a hill-holding control method and device, a computer storage medium, a computer program product, and an electronic control unit ECU. Background Art
[0002] As a driving condition of a vehicle, the importance of its control method to the safety of the vehicle is self-evident. At present, the existing vehicle holding hill control method is mainly to adjust the speed torque closed-loop PI controller when the vehicle enters the holding hill control, but this adjustment may cause the torque adjustment response to be slow, the torque speed cannot keep up, and finally lead to a long slip distance.
[0003] In addition, the vehicle's holding torque is different under different slopes and different loads. In order to save costs, most existing vehicles (such as electric vehicles) are not equipped with inclination sensors, and lack a solution for accurately calculating the holding torque (under different slopes and different loads). Summary of the invention
[0004] According to one aspect of the present application, a hill-holding control method is provided, the method comprising: receiving an actual speed nEm of a motor; determining a feedforward torque tqFdfwd based on a first speed difference Δn between the actual speed nEm of the motor and a filtered motor speed nEmFild; and determining a torque demand value tqEm based on the feedforward torque tqFdfwd, the torque demand value tqEm being used to provide to the motor in order to achieve vehicle parking.
[0005] As a supplement or alternative to the above solution, in the above method, the filtered motor speed nEmFild is determined according to the actual speed nEm of the motor and the filter coefficient α of the first-order filter.
[0006] As a supplement or alternative to the above-mentioned scheme, in the above-mentioned method, determining the feedforward torque tqFdfwd based on the first speed difference Δn between the actual speed nEm of the motor and the filtered motor speed nEmFild includes: determining the acceleration a of the vehicle based on the first speed difference Δn; and determining the feedforward torque tqFdfwd based on the acceleration a.
[0007] As a supplement or alternative to the above-mentioned scheme, in the above-mentioned method, determining the torque demand value tqEm based on the feed-forward torque tqFdfwd includes: determining the second speed difference ΔnEm between the motor speed demand value nEmDes and the actual motor speed nEm; using a PI controller to determine the torque demand value tqEm based on the second speed difference ΔnEm and the feed-forward torque tqFdfwd.
[0008] As a supplement or alternative to the above solution, in the above method, the feedforward torque tqFdfwd is gradually applied to the PI controller from 0 with a fixed or variable slope within a preset time.
[0009] As a supplement or alternative to the above scheme, in the above method, the torque demand value tqEm is determined according to the following formula: tqEm=Kp*ΔnEm+Ki*∫ΔnEmdt+tqFdfwd, wherein Kp is the proportional coefficient of the PI controller, Ki is the integral coefficient of the PI controller, and tqFdfwd is the feedforward torque applied to the PI controller.
[0010] According to another aspect of the present application, a hill-holding control device is provided, the device comprising: a receiving device for receiving an actual speed nEm of a motor; a first determining device for determining a feedforward torque tqFdfwd based on a first speed difference Δn between the actual speed nEm of the motor and a filtered motor speed nEmFild; and a second determining device for determining a torque demand value tqEm based on the feedforward torque tqFdfwd, the torque demand value tqEm being provided to the motor to achieve vehicle parking.
[0011] As a supplement or alternative to the above solution, in the above device, the filtered motor speed nEmFild is determined according to the actual speed nEm of the motor and the filter coefficient α of the first-order filter.
[0012] As a supplement or alternative to the above solution, in the above device, the first determination device is configured to: determine the acceleration a of the vehicle based on the first rotation speed difference Δn; and determine the feedforward torque tqFdfwd based on the acceleration a.
[0013] As a supplement or alternative to the above-mentioned scheme, in the above-mentioned device, the second determination device is configured to: determine the second speed difference ΔnEm between the motor speed demand value nEmDes and the actual motor speed nEm; use a PI controller to determine the torque demand value tqEm based on the second speed difference ΔnEm and the feedforward torque tqFdfwd.
[0014] As a supplement or alternative to the above solution, in the above device, the feedforward torque tqFdfwd is gradually applied to the PI controller from 0 at a fixed or variable slope within a preset time.
[0015] As a supplement or alternative to the above-mentioned scheme, in the above-mentioned device, the torque demand value tqEm is determined according to the following formula: tqEm=Kp*ΔnEm+Ki*∫ΔnEmdt+tqFdfwd, wherein Kp is the proportional coefficient of the PI controller, Ki is the integral coefficient of the PI controller, and tqFdfwd is the feedforward torque applied to the PI controller.
[0016] According to another aspect of the present application, a computer-readable storage medium is provided, wherein the medium includes instructions, and the instructions execute the above-mentioned method when executed.
[0017] According to another aspect of the present application, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the method as described above is implemented.
[0018] According to yet another aspect of the present application, an electronic control unit ECU is provided, wherein the electronic control unit ECU includes the hill-holding control device as described above.
[0019] The hill-staying control scheme of the embodiment of the present application determines the feedforward torque tqFdfwd based on the first speed difference Δn between the received actual speed nEm of the motor and the filtered motor speed nEmFild, and determines the torque demand value tqEm based on the feedforward torque tqFdfwd, and the torque demand value tqEm is used to provide to the motor to achieve the parking of the vehicle. The above-mentioned hill-staying control scheme adopts the method of calculating the feedforward torque tqFdfwd in advance and determining the torque demand value tqEm according to the feedforward torque to speed up the torque response speed and reduce the negative impact that may be caused by the slow torque response. In addition, the above-mentioned hill-staying control scheme determines the feedforward torque tqFdfwd based on the first speed difference Δn (rather than the vehicle speed) between the actual speed nEm of the motor and the filtered motor speed nEmFild, which is conducive to accurately calculating the hill-staying torque under different slopes and different load conditions, ensuring that the vehicle can park normally on the slope. Finally, in order to achieve a balance between response speed and driving experience, in one embodiment of the present application, the hill-holding control scheme does not directly apply the feedforward torque tqFdfwd to the PI controller, but gradually applies the feedforward torque tqFdfwd to the PI controller from 0 at a fixed or variable slope within a preset time to avoid the phenomenon of the vehicle rushing forward significantly. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The above and other objects and advantages of the present application will become more fully apparent from the following detailed description in conjunction with the accompanying drawings, wherein the same or similar elements are represented by the same reference numerals.
[0021] Figure 1 A schematic flow chart of a hill-holding control method according to an embodiment of the present application is shown;
[0022] Figure 2 A schematic structural diagram of a hill-holding control device according to an embodiment of the present application is shown;
[0023] Figure 3 A schematic diagram of a structure in which a feedforward torque tqFdfwd is applied to a PI controller according to an embodiment of the present application is shown;
[0024] Figure 4 A simulation diagram of a motor speed nEmFild after filtering and an actual motor speed nEm according to an embodiment of the present application is shown; and
[0025] Figure 5 The force analysis diagram of a vehicle on a slope is shown. DETAILED DESCRIPTION
[0026] Hereinafter, a hill-holding control scheme according to various exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings.
[0027] Figure 1 FIG. 1 is a flow chart of a hill-holding control method 1000 according to an embodiment of the present application. Figure 1 As shown, the hill-holding control method 1000 includes the following steps:
[0028] In step S110, the actual speed nEm of the motor is received;
[0029] In step S120, a feedforward torque tqFdfwd is determined based on a first speed difference Δn between an actual speed nEm of the motor and a filtered motor speed nEmFild; and
[0030] In step S130 , a torque demand value tqEm is determined based on the feedforward torque tqFdfwd, and the torque demand value tqEm is used to provide to the motor so as to achieve parking of the vehicle.
[0031] In the context of the present application, the term "filtered motor speed nEmFild" means the speed value obtained after applying the actual speed nEm of the motor to the filter. In one or more embodiments, the actual speed nEm of the motor can be applied to a first-order low-pass filter to obtain the filtered motor speed nEmFild. The advantage of setting "filtering" is that after filtering (for example, first-order filtering), the filtered motor speed nEmFild is a relatively smooth value. In contrast, the actual speed nEm of the motor is the real-time speed, and there may be a certain error. Therefore, the error of calculating the speed difference (i.e., the first speed difference Δn) based on the actual speed nEm of the motor and the filtered motor speed nEmFild will also be smaller.
[0032] refer to Figure 4 , which shows a simulation schematic diagram of the motor speed nEmFild after filtering and the actual speed nEm of the motor according to an embodiment of the present application. In one embodiment, the actual speed nEm of the motor is filtered to obtain the filtered motor speed nEmFild after a first-order low-pass filter, and the filtered motor speed nEmFild and the actual speed nEm of the motor should satisfy the following formula:
[0033] nEmFild(n)=α*nEm+(1-α)*nEmFild(n-1),
[0034] Among them, nEmFild(n-1) represents the motor speed after the last filtering, nEmFild(n) represents the motor speed after the current filtering, and α represents the filter coefficient (for example, 0.01). In other words, the motor speed nEmFild after filtering can be determined according to the actual motor speed nEm and the filter coefficient α of the first-order filter.
[0035] Continue to refer Figure 4 ,It can be seen from the simulation waveform that in the first 0.2 seconds, the filtered motor speed nEmFild is quickly catching up with the actual motor speed nEm, and the speed difference between the two is unstable. After 0.2 seconds, the speed difference between the filtered motor speed nEmFild and the actual motor speed nEm is stable.
[0036] Moreover, after simulation, the following data can be obtained:
[0037]
[0038] According to the above simulation results, the following conclusions can be drawn:
[0039] (1) The first speed difference Δn is proportional to the acceleration a;
[0040] (2) The delay time is inversely proportional to the filter coefficient α.
[0041] The above table is used as an example in the context of this application, not as a limitation. The table can prove that the acceleration of the sliding car is different at different slopes, and the sliding car acceleration can be reflected by Δn. Because the linearity of Δn at different slopes is relatively good, it can almost completely reflect the acceleration characteristics.
[0042] In addition, the linearity of Δn is very good, indicating that the filtering effect of nEmFild is not bad, indicating that the first-order filtering here is a reasonable solution. The inventor of this application mainly considers the following two aspects to set the first-order filtering:
[0043] First, after the actual motor speed nEm is filtered by the first order, the filtered motor speed nEmFild has a certain delay relative to the actual speed nEm. It is because of this delay that the value of nEm will always be larger than nEmFild at the same time, so Δn exists. It is because of this Δn that the feedforward torque can be calculated. It can be seen from the simulation diagram that Δn is unstable at the beginning, but then it tends to be stable.
[0044] Second, the use of first-order filtering can make the first speed difference Δn tend to stabilize in a very short time (the specific time depends on the filter coefficient). Compared with multi-order filtering, the first order is simpler to implement, more stable, and has a shorter stabilization time.
[0045] In step S120 , a feedforward torque tqFdfwd is determined based on a first speed difference Δn between an actual speed nEm of the motor and a filtered motor speed nEmFild.
[0046] Taking the uphill as an example, the force analysis of the vehicle on the slope is as follows Figure 5 As shown. Figure 5 As shown in the figure, if the driving torque tqEm is greater than the load torque tqLoad, the vehicle will generate an upward acceleration, otherwise, it will generate a downward acceleration. During the braking process, the physical friction force tqFric generated by braking is greater than (equal to) tqLoad, which can ensure that the vehicle is stationary. After releasing the brake, since tqFric = 0, there is no torque that can overcome the load torque tqLoad, so the vehicle will slide backward. In order to ensure the shortest possible sliding distance, the value of the load torque tqLoad needs to be accurately calculated. This ensures that after releasing the brake, a driving torque (equal to the load torque tqLoad) is immediately generated, and the vehicle still remains stationary, realizing the hill-holding function.
[0047] Since the vehicle speed value is not very accurate at low speeds, in the context of this application, the motor speed is used instead of the vehicle speed to calculate the load torque tqLoad:
[0048]
[0049] Where m is the mass of the vehicle, is the rate of change of the motor speed. Since the value of tqLoad is a fixed value, its size is determined by the slope and the vehicle weight. The slope size corresponds to the acceleration, that is, the rate of change of the motor speed. Therefore, without the need for a slope sensor, the load torque can be calculated using the motor speed change rate. When entering a stationary slope, the drive torque tqEm is 0, and there is only load torque at this time. The calculation formula is as follows:
[0050]
[0051] At the moment of entering the hill-parking state, the vehicle has a load torque tqLoad and a motor speed (negative value) at that moment. During the hill-slipping period, the absolute value of the vehicle speed is gradually decreasing. At this time, the torque applied to the vehicle includes a load torque tqLoad and a smaller driving torque tqEm. When the vehicle is on the hill, the vehicle has a load torque tqLoad and a larger driving torque tqEm, and the driving torque tqEm=tqLoad. In one embodiment, tqEm comes from the feedforward torque tqFdfwd, and tqEm=tqFdfwd.
[0052] In one embodiment, step S120 includes: determining the acceleration a of the vehicle based on the first speed difference Δn; and determining the feedforward torque tqFdfwd based on the acceleration a. For example, the acceleration a of the vehicle may be determined according to the rate of change of the first speed difference Δn.
[0053] In step S130, a torque demand value tqEm is determined based on the feedforward torque tqFdfwd, and the torque demand value tqEm is used to provide to the motor so as to achieve parking of the vehicle. In one embodiment, step S130 includes: determining a second speed difference ΔnEm between the motor speed demand value nEmDes and the motor actual speed nEm; and using a PI controller to determine the torque demand value tqEm based on the second speed difference ΔnEm and the feedforward torque tqFdfwd.
[0054] refer to Figure 3 , which shows a schematic diagram of a structure in which a feedforward torque tqFdfwd is applied to a PI controller according to an embodiment of the present application. Figure 3 As shown in the figure, nEmDes represents the expected speed of the motor (nEmDes is always set to 0 during the slope holding process). The expected speed is used for proportional integral regulation to achieve closed-loop speed regulation, thereby achieving approximate control of the actual motor speed nEm from the initial speed (the speed of the motor when the anti-slope function is turned on) to zero (nEmDes is 0). In fact, the actual motor speed nEm is a process of slowly approaching 0 from a negative speed (such as -50rpm).
[0055] Continue to refer Figure 3 The second speed difference ΔnEm represents the difference between the desired speed nEmDes and the actual speed nEm of the motor. It should be noted that the second speed difference ΔnEm is different from the first speed difference Δn.
[0056] like Figure 3As shown in the PI controller 3000, the actual motor speed nEm is applied to the filter 310 to obtain the filtered motor speed nEmFild. The first speed difference Δn represents the speed difference between the actual motor speed nEm and the filtered motor speed nEmFild. After the first speed difference Δn is applied to the calculation device 320, the feedforward torque tqFdfwd can be obtained. The feedforward torque tqFdfwd and the proportional and integral values controlled based on the second speed difference ΔnEm are applied to the adder 330 to obtain the torque demand value tqEm. That is, in one embodiment, the torque demand value tqEm can be determined according to the following formula:
[0057] tqEm=Kp*ΔnEm+Ki*∫ΔnEmdt+tqFdfwd,
[0058] Wherein, Kp is the proportional coefficient of the PI controller, Ki is the integral coefficient of the PI controller, and tqFdfwd is the feedforward torque applied to the PI controller.
[0059] In one embodiment, the feedforward torque tqFdfwd is set to be gradually applied to the PI controller with a fixed or variable slope starting from 0 within a preset time. In other words, the feedforward torque tqFdfwd does not act directly on the PI controller (for example, in a step-up manner) because although the fastest response speed can be obtained by directly applying the feedforward torque tqFdfwd to the PI controller, the vehicle will have a significant forward rush phenomenon and the driving experience is poor. Therefore, in order to balance the response speed and driving experience, the feedforward torque tqFdfwd can be applied by gradually increasing the feedforward torque value. In one embodiment, the feedforward torque value rises linearly with a fixed slope. In another embodiment, the feedforward torque value rises in a way that the slope is first large and then small. In another embodiment, the feedforward torque value rises in a way that the slope is first small, medium large, and then small. In this way, the vehicle can be prevented from shaking and the driving experience can be improved.
[0060] In addition, it is easy for a person skilled in the art to understand that the hill-staying control method 1000 provided in the above one or more embodiments of the present application can be implemented by a computer program. For example, the computer program is included in a computer program product, and when the computer program is executed by a processor, the hill-staying control method 1000 of one or more embodiments of the present application is implemented. For another example, when a computer storage medium (such as a USB flash drive) storing the computer program is connected to a computer, the hill-staying control method 1000 of one or more embodiments of the present application can be executed by running the computer program.
[0061] Figure 2 FIG. 2 shows a schematic structural diagram of a hill-holding control device 2000 according to an embodiment of the present application. Figure 2As shown, the hill-holding control device 2000 includes: a receiving device 210, a first determining device 220 and a second determining device 230. The receiving device 210 is used to receive the actual speed nEm of the motor; the first determining device 220 is used to determine the feedforward torque tqFdfwd based on the first speed difference Δn between the actual speed nEm of the motor and the filtered motor speed nEmFild; and the second determining device 230 is used to determine the torque demand value tqEm based on the feedforward torque tqFdfwd, and the torque demand value tqEm is used to provide to the motor to achieve the parking of the vehicle.
[0062] In the context of the present application, the term "filtered motor speed nEmFild" means the speed value obtained after applying the actual speed nEm of the motor to the filter. In one or more embodiments, the actual speed nEm of the motor can be applied to a first-order low-pass filter to obtain the filtered motor speed nEmFild. The advantage of setting "filtering" is that after filtering (for example, first-order filtering), the filtered motor speed nEmFild is a relatively smooth value. In contrast, the actual speed nEm of the motor is the real-time speed, and there may be a certain error. Therefore, the error of calculating the speed difference (i.e., the first speed difference Δn) based on the actual speed nEm of the motor and the filtered motor speed nEmFild will also be smaller.
[0063] In one embodiment, the motor speed nEmFild after filtering is determined according to the actual motor speed nEm and the filter coefficient α of the first-order filter. For example, the motor speed nEmFild after filtering and the actual motor speed nEm should satisfy the following formula:
[0064] nEmFild(n)=α*nEm+(1-α)*nEmFild(n-1),
[0065] Among them, nEmFild(n-1) represents the motor speed after the previous filtering, nEmFild(n) represents the motor speed after the current filtering, and α represents the filtering coefficient (for example, 0.01).
[0066] In one or more embodiments, the receiving device 210 may include a resolver device (eg, a rotary transformer) for acquiring an actual rotation speed of the motor.
[0067] In one embodiment, the first determining device 220 is configured to calculate the feed-forward torque tqFdfwd according to the following formula:
[0068]
[0069] Where m is the mass of the vehicle, is the rate of change of motor speed.
[0070] In another embodiment, the first determining device 220 is configured to determine the acceleration a of the vehicle based on the first rotation speed difference Δn; and determine the feed-forward torque tqFdfwd based on the acceleration a.
[0071] In one embodiment, the second determining device 230 is configured to: determine a second speed difference ΔnEm between the motor speed demand value nEmDes and the motor actual speed nEm; and determine the torque demand value tqEm based on the second speed difference ΔnEm and the feedforward torque tqFdfwd using a PI controller. The torque demand value tqEm can be determined according to the following formula:
[0072] tqEm=Kp*ΔnEm+Ki*∫ΔnEmdt+tqFdfwd,
[0073] Wherein, Kp is the proportional coefficient of the PI controller, Ki is the integral coefficient of the PI controller, and tqFdfwd is the feedforward torque applied to the PI controller.
[0074] In one embodiment, the feedforward torque tqFdfwd is gradually applied to the PI controller from 0 with a fixed or variable slope within a preset time. In other words, the feedforward torque tqFdfwd does not act directly on the PI controller (for example, in a step-up manner) because although the fastest response speed can be obtained by directly applying the feedforward torque tqFdfwd to the PI controller, the vehicle will have a significant forward rush and the driving experience is poor. Therefore, in order to balance the response speed and driving experience, the feedforward torque tqFdfwd can be applied by gradually increasing the feedforward torque value. In one embodiment, the feedforward torque value rises linearly with a fixed slope. In another embodiment, the feedforward torque value rises in a way that the slope is first large and then small. In another embodiment, the feedforward torque value rises in a way that the slope is first small, medium large, and then small. In this way, the vehicle can be prevented from shaking and the driving experience can be improved.
[0075] In one embodiment, the hill-holding control device 2000 can be integrated into various types of electronic control units ECU. In one embodiment, the electronic control unit ECU can be installed in a vehicle.
[0076] In summary, the hill-staying control scheme of the embodiment of the present application determines the feedforward torque tqFdfwd based on the first speed difference Δn between the received actual speed nEm of the motor and the filtered motor speed nEmFild, and determines the torque demand value tqEm based on the feedforward torque tqFdfwd, and the torque demand value tqEm is used to provide to the motor to achieve the parking of the vehicle. The above-mentioned hill-staying control scheme adopts the method of calculating the feedforward torque tqFdfwd in advance and determining the torque demand value tqEm according to the feedforward torque to speed up the torque response speed and reduce the negative impact that may be caused by the slow torque response. In addition, the above-mentioned hill-staying control scheme determines the feedforward torque tqFdfwd based on the first speed difference Δn (rather than the vehicle speed) between the actual speed nEm of the motor and the filtered motor speed nEmFild, which is conducive to accurately calculating the hill-staying torque under different slopes and different load conditions, ensuring that the vehicle can park normally on the slope. Finally, in order to achieve a balance between response speed and driving experience, in one embodiment of the present application, the hill-holding control scheme does not directly apply the feedforward torque tqFdfwd to the PI controller, but gradually applies the feedforward torque tqFdfwd to the PI controller from 0 at a fixed or variable slope within a preset time to avoid the phenomenon of the vehicle rushing forward significantly.
[0077] The above examples mainly illustrate the hill-holding control scheme of the embodiments of the present application. Although only some of the embodiments of the present application (taking the hill-holding as an example) are described, it should be understood by those skilled in the art that the present application can be implemented in many other forms without departing from its subject matter and scope (for example, the hill-holding during the downhill process should also be within the scope of protection of this patent). Therefore, the examples and embodiments shown are regarded as illustrative rather than restrictive, and the present application may cover various modifications and substitutions without departing from the spirit and scope of the present application as defined in the claims.
Claims
1. A hill-holding control method, characterized in that: The method comprises: Receive the actual speed nEm of the motor; Determine a feedforward torque tqFdfwd based on a first speed difference Δn between an actual speed nEm of the motor and a filtered motor speed nEmFild; and A torque demand value tqEm is determined based on the feed-forward torque tqFdfwd, and the torque demand value tqEm is used to provide to the motor so as to achieve parking of the vehicle.
2. The method of claim 1, wherein: The filtered motor speed nEmFild is determined according to the actual speed nEm of the motor and the filter coefficient α of the first-order filter.
3. The method according to claim 1 or 2, wherein: Based on a first speed difference Δn between an actual speed nEm of the motor and a filtered motor speed nEmFild, determining a feedforward torque tqFdfwd comprises: determining an acceleration a of the vehicle based on the first rotation speed difference Δn; and The feed-forward torque tqFdfwd is determined based on the acceleration a.
4. The method of claim 1, wherein: Determining the torque demand value tqEm based on the feedforward torque tqFdfwd includes: Determine a second speed difference ΔnEm between the motor speed demand value nEmDes and the motor actual speed nEm; The torque demand value tqEm is determined based on the second speed difference ΔnEm and the feedforward torque tqFdfwd using a PI controller.
5. The method of claim 4, wherein: The feedforward torque tqFdfwd is gradually applied to the PI controller starting from 0 with a fixed or variable slope within a preset time.
6. The method according to claim 4 or 5, wherein: The torque demand value tqEm is determined according to the following formula: tqEm=Kp*ΔnEm+Ki*∫ΔnEmdt+tqFdfwd, Wherein, Kp is the proportional coefficient of the PI controller, Ki is the integral coefficient of the PI controller, and tqFdfwd is the feedforward torque applied to the PI controller.
7. A hill-holding control device, characterized in that: The device comprises: A receiving device, used for receiving the actual speed nEm of the motor; a first determining device for determining a feedforward torque tqFdfwd based on a first speed difference Δn between an actual speed nEm of the motor and a filtered motor speed nEmFild; and The second determining device is used to determine a torque demand value tqEm based on the feedforward torque tqFdfwd, wherein the torque demand value tqEm is used to provide the motor to achieve parking of the vehicle.
8. The device of claim 7, wherein: The filtered motor speed nEmFild is determined according to the actual speed nEm of the motor and the filter coefficient α of the first-order filter.
9. The device according to claim 7 or 8, wherein: The first determining device is configured to: determining an acceleration a of the vehicle based on the first rotation speed difference Δn; and The feed-forward torque tqFdfwd is determined based on the acceleration a.
10. The device of claim 7, wherein: The second determining device is configured to: Determine a second speed difference ΔnEm between the motor speed demand value nEmDes and the motor actual speed nEm; The torque demand value tqEm is determined based on the second speed difference ΔnEm and the feedforward torque tqFdfwd using a PI controller.
11. The device of claim 10, wherein: The feedforward torque tqFdfwd is gradually applied to the PI controller starting from 0 with a fixed or variable slope within a preset time.
12. The device according to claim 10 or 11, wherein: The torque demand value tqEm is determined according to the following formula: tqEm=Kp*ΔnEm+Ki*∫ΔnEmdt+tqFdfwd, Wherein, Kp is the proportional coefficient of the PI controller, Ki is the integral coefficient of the PI controller, and tqFdfwd is the feedforward torque applied to the PI controller.
13. A computer-readable storage medium, characterized in that: The medium includes instructions that, when executed, perform the method of any one of claims 1 to 6.
14. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.
15. An electronic control unit ECU, characterized in that: The electronic control unit ECU includes the hill-holding control device according to any one of claims 7 to 12.