CN109720316B - Downhill auxiliary control method and device and vehicle - Google Patents
Downhill auxiliary control method and device and vehicle Download PDFInfo
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- CN109720316B CN109720316B CN201711043238.2A CN201711043238A CN109720316B CN 109720316 B CN109720316 B CN 109720316B CN 201711043238 A CN201711043238 A CN 201711043238A CN 109720316 B CN109720316 B CN 109720316B
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Abstract
The disclosure relates to a downhill auxiliary control method and device and a vehicle. The method comprises the following steps: determining a target vehicle speed of a vehicle on a current road surface downhill; determining a rate of change of braking force according to a current vehicle speed of the vehicle, the target vehicle speed, and a difference value of the current vehicle speed; controlling the braking force of the vehicle according to the determined rate of change of the braking force. In this way, the braking force can be adjusted in consideration of the comfort of the occupant in controlling the braking of the vehicle. Compared with the technology of controlling the braking of the vehicle by the braking force with the preset magnitude, the technology of the present disclosure increases the stability of the whole vehicle and reduces the discomfort of passengers when the vehicle travels downhill.
Description
Technical Field
The disclosure relates to the field of vehicle auxiliary driving, in particular to a downhill auxiliary control method and device and a vehicle.
Background
As vehicle technology has improved, technicians have developed various driving assistance systems. For example, a lane keeping assist system, an automatic parking assist system, a reverse assist system, and the like. In recent years, steep descent systems have been developed. A steep descent system, also known as a hill control system or a downhill assist control system, is capable of automatically controlling a vehicle to safely pass through a downhill section without the driver stepping on a brake pedal. During this time, the brake automatically controls the wheels and the driver can concentrate completely on controlling the steering wheel.
In the prior art, a steep descent system usually only considers that a vehicle keeps a constant speed when running downhill, and when the actual speed is higher than the target speed, the braking force is increased; when the actual vehicle speed is less than the target vehicle speed, the braking force is reduced. Such a steep descent system does not take into consideration the problem that when the actual vehicle speed and the target vehicle speed are greatly different from each other, if the vehicle is suddenly decelerated with a large braking force, the ride comfort of the driver and the passenger is uncomfortable. In addition, when the control is performed at a fixed target vehicle speed or at a vehicle speed that does not satisfy the intention of the driver, the target vehicle speed on the downhill differs greatly from the driver's desired vehicle speed and is difficult to adjust by the accelerator and the brake, not from the viewpoint of the user. The conventional downhill auxiliary control system also has an upper speed control limit, so that potential safety hazards exist to a certain extent, namely when the current speed is high, the vehicle cannot enter the downhill auxiliary control system, and at the moment, a driver needs to manually control the speed.
Disclosure of Invention
The invention aims to provide a downhill auxiliary control method, a downhill auxiliary control device and a vehicle, which are simple and practical and can enhance the comfort of passengers.
In order to achieve the above object, the present disclosure provides a downhill assist control method. The method comprises the following steps: determining a target vehicle speed of a vehicle on a current road surface downhill; determining a rate of change of braking force according to a current vehicle speed of the vehicle, the target vehicle speed, and a difference value of the current vehicle speed; controlling the braking force of the vehicle according to the determined rate of change of the braking force.
Optionally, the step of determining the rate of change of the braking force according to both the current vehicle speed of the vehicle, the target vehicle speed, and the difference value of the current vehicle speed comprises: and searching the change rate of the braking force corresponding to the current vehicle speed of the vehicle, the difference value of the target vehicle speed and the current vehicle speed in the prestored change rate related data.
Wherein the rate of change associated data is generated by: setting an acceleration change rate interval corresponding to the current vehicle speed, the difference value of the target vehicle speed and the current vehicle speed; applying a plurality of predetermined braking force change rates to the vehicle one by one, and detecting a change rate of the acceleration of the vehicle corresponding to each braking force change rate; determining the change rate of the braking force corresponding to the difference value of the current vehicle speed, the target vehicle speed and the current vehicle speed according to the change rate of the braking force of which the corresponding change rate of the acceleration is within the set acceleration change rate interval; fitting a braking force change rate correlation data curve according to the determined values of the difference values of the plurality of groups of different current vehicle speeds, the target vehicle speed and the current vehicle speed and the corresponding change rate of the braking force; and obtaining the change rate related data through the braking force change rate related data curve.
Optionally, the step of determining the change rate of the braking force corresponding to the difference between the current vehicle speed, the target vehicle speed, and the current vehicle speed according to the change rate of the braking force of which the change rate of the corresponding acceleration is within the set acceleration change rate section includes: when only one of the rates of change of the braking force is within the set acceleration rate change interval, determining the rate of change of the braking force as the rate of change of the braking force corresponding to the current vehicle speed, the difference value between the target vehicle speed and the current vehicle speed; and when the change rates of the plurality of braking forces are within the set acceleration change rate interval, determining the change rate of the braking force corresponding to the current vehicle speed, the difference value of the target vehicle speed and the current vehicle speed by carrying out an average value method or a median value method on the change rates of the plurality of braking forces.
Optionally, the step of fitting a braking force change rate related data curve according to the determined values of the difference values between the plurality of different sets of the current vehicle speed, the target vehicle speed and the current vehicle speed and the corresponding change rate of the braking force comprises: and fitting the change rate associated data curve by a least square method, an averaging method or an interpolation method according to the determined values of the difference values of the plurality of different groups of the current vehicle speed, the target vehicle speed and the current vehicle speed and the corresponding change rate of the braking force.
Optionally, the step of determining the target vehicle speed of the vehicle at the current road surface downhill comprises: acquiring the expected speed of the vehicle on the current road surface downhill; determining the maximum vehicle speed allowed by the current road surface downhill; and determining the vehicle speed value of one of the expected vehicle speed, the allowed maximum vehicle speed and the current vehicle speed with the minimum value as the target vehicle speed.
Optionally, the step of determining the maximum vehicle speed allowed by the current road surface downhill comprises: acquiring the friction coefficient and the gradient of the current road surface; in the previously stored maximum vehicle speed-related data, an allowable maximum vehicle speed corresponding to both the friction coefficient and the gradient of the current road surface is found.
Optionally, the step of obtaining the expected vehicle speed of the vehicle at the current road surface downhill comprises: receiving a setting instruction containing a desired vehicle speed; and when the setting instruction is received, determining the expected vehicle speed according to the setting instruction, and storing the friction coefficient and the gradient of the current road surface in a correlation manner with the expected vehicle speed contained in the setting instruction.
Optionally, the step of obtaining the expected vehicle speed of the vehicle at the current road surface downhill further comprises: and when the setting instruction is not received, searching the stored expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface, and if the expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface is not searched, determining the vehicle speed when the downhill auxiliary control system is triggered as the expected vehicle speed.
Optionally, the step of controlling the braking force of the vehicle according to the determined rate of change of the braking force further comprises: detecting a braking force corresponding to a brake pedal of the vehicle; when the braking force corresponding to the brake pedal of the vehicle is smaller than the current braking force, controlling the braking force provided by the downhill auxiliary control system to control the vehicle; and when the braking force corresponding to the brake pedal of the vehicle is greater than the current braking force, controlling the braking force provided by the brake pedal to control the vehicle.
The present disclosure also provides a downhill assist control device. The device comprises: the target vehicle speed determining module is used for determining the target vehicle speed of the vehicle on the current road surface downhill; the braking force change rate determining module is connected with the target vehicle speed determining module and used for determining the change rate of the braking force according to the current vehicle speed of the vehicle, the difference value of the target vehicle speed and the current vehicle speed; and the braking force control module is connected with the braking force change rate determination module and is used for controlling the braking force of the vehicle according to the determined braking force change rate.
Optionally, the braking force change rate determination module includes: and the braking force change rate searching submodule is used for searching the braking force change rate corresponding to the current vehicle speed of the vehicle, the difference value of the target vehicle speed and the current vehicle speed in the prestored change rate related data.
Wherein the rate of change associated data is generated by: setting an acceleration change rate interval corresponding to the current vehicle speed, the difference value of the target vehicle speed and the current vehicle speed; applying a plurality of predetermined braking force change rates to the vehicle one by one, and detecting a change rate of the acceleration of the vehicle corresponding to each braking force change rate; determining the change rate of the braking force corresponding to the difference value of the current vehicle speed, the target vehicle speed and the current vehicle speed according to the change rate of the braking force of which the corresponding change rate of the acceleration is within the set acceleration change rate interval; fitting a braking force change rate correlation data curve according to the determined values of the difference values of the plurality of groups of different current vehicle speeds, the target vehicle speed and the current vehicle speed and the corresponding change rate of the braking force; and obtaining the change rate related data through the braking force change rate related data curve.
Optionally, the target vehicle speed determination module comprises: the expected vehicle speed obtaining submodule is used for obtaining the expected vehicle speed of the vehicle on the current road surface downhill; the maximum vehicle speed determining submodule is used for determining the maximum vehicle speed allowed by the current road surface downhill; and the target vehicle speed determining submodule is respectively connected with the expected vehicle speed obtaining submodule and the maximum vehicle speed determining submodule and is used for determining the vehicle speed value of one of the expected vehicle speed, the allowed maximum vehicle speed and the current vehicle speed with the minimum value as the target vehicle speed.
Optionally, the maximum vehicle speed determination submodule includes: the friction coefficient and gradient obtaining submodule is used for obtaining the friction coefficient and the gradient of the current road surface; and the maximum vehicle speed searching submodule is connected with the friction coefficient and gradient obtaining submodule and is used for searching the allowable maximum vehicle speed corresponding to the friction coefficient and the gradient of the current road surface in the prestored maximum vehicle speed related data.
Optionally, the desired vehicle speed acquisition sub-module includes: the receiving submodule is used for receiving a setting instruction containing the expected vehicle speed; and the first expected vehicle speed determining submodule is connected with the receiving submodule and used for determining the expected vehicle speed according to the setting instruction when the setting instruction is received, and storing the friction coefficient and the gradient of the current road surface and the expected vehicle speed contained in the setting instruction in an associated manner.
Optionally, the desired vehicle speed acquisition sub-module includes: and the second expected vehicle speed determining submodule is used for searching the stored expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface when the setting instruction is not received, and determining the vehicle speed when the downhill auxiliary control system is triggered as the expected vehicle speed if the expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface is not searched.
Optionally, the braking force control module further comprises: the detection submodule is used for detecting the braking force corresponding to a brake pedal of the vehicle; the first control submodule is connected with the detection submodule and used for controlling the braking force provided by the downhill auxiliary control system to control the vehicle when the braking force corresponding to a brake pedal of the vehicle is smaller than the current braking force; and the second control submodule is connected with the detection submodule and used for controlling the braking force provided by the brake pedal to control the vehicle when the braking force corresponding to the brake pedal of the vehicle is greater than the current braking force.
The present disclosure also provides a vehicle including the downhill assist control apparatus described above.
According to the technical scheme, the change rate of the braking force of the vehicle when the current road surface is on the downhill is determined according to the current vehicle speed, the target vehicle speed and the difference value of the current vehicle speed. In this way, the braking force can be adjusted in consideration of the comfort of the occupant in controlling the braking of the vehicle. Compared with the technology of controlling the braking of the vehicle by the braking force with the preset magnitude, the technology of the present disclosure increases the stability of the whole vehicle and reduces the discomfort of passengers when the vehicle travels downhill.
Additional features and advantages of the disclosure will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:
FIG. 1 is a flow chart of a downhill assist control method provided by an exemplary embodiment;
FIG. 2 is a flow chart of a downhill assist control method provided by another exemplary embodiment;
fig. 3 is a block diagram of a downhill assist control device according to an exemplary embodiment.
Detailed Description
The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.
Fig. 1 is a flowchart of a downhill assist control method according to an exemplary embodiment. As shown in fig. 1, the method may include the following steps.
In step S1, a target vehicle speed for the vehicle on the current road surface downhill is determined.
In step S2, the rate of change of the braking force is determined from both the current vehicle speed of the vehicle, the target vehicle speed, and the difference value of the current vehicle speed.
In step S3, the braking force of the vehicle is controlled according to the determined rate of change of the braking force.
When the vehicle goes downhill, the driver can start the downhill auxiliary control system by means of a switch button of the downhill auxiliary control system. In this case, the system may determine a target vehicle speed, which is a vehicle speed that is ultimately achieved when the vehicle is controlled to go downhill, and may be a preset vehicle speed or a vehicle speed corresponding to a parameter such as a road surface condition. The current vehicle speed may be detected by a sensor.
When the vehicle runs straight at a constant speed, the comfort level of passengers is the highest, the comfort level is poorer when the vehicle runs at a higher acceleration, and the comfort level is poorer when the acceleration change rate is higher. The rate of change of braking force represents the rate of change of vehicle acceleration, which is an important parameter in measuring passenger comfort. In the present disclosure, a more appropriate rate of change of the braking force is determined from the current vehicle speed, the target vehicle speed, and the difference value between the current vehicle speed, and the target vehicle speed, and the braking force applied to the vehicle is determined from the determined rate of change of the braking force.
According to the technical scheme, the change rate of the braking force of the vehicle when the current road surface is on the downhill is determined according to the current vehicle speed, the target vehicle speed and the difference value of the current vehicle speed. In this way, the braking force can be adjusted in consideration of the comfort of the occupant in controlling the braking of the vehicle. Compared with the technology of controlling the braking of the vehicle by the braking force with the preset magnitude, the technology of the present disclosure increases the stability of the whole vehicle and reduces the discomfort of passengers when the vehicle travels downhill.
In an embodiment of the present disclosure, the change rate related data in which the change rate of the braking force corresponding to the above-described two is directly searched for may be stored in the vehicle in advance. In this embodiment, on the basis of fig. 1, the step of determining the rate of change of the braking force based on both the current vehicle speed of the vehicle, the difference value between the target vehicle speed and the current vehicle speed (at step S2) may include: in the previously stored change rate-related data, the change rate of the braking force corresponding to the current vehicle speed of the vehicle, the target vehicle speed, and the difference value of the current vehicle speed are searched for.
Wherein the change rate related data may be generated in advance and stored in the vehicle, and may be generated by:
1) an acceleration change rate section corresponding to a difference between the current vehicle speed, the target vehicle speed, and the current vehicle speed is set. For example, the acceleration change rate interval corresponding to the current vehicle speed of 30km/h and the vehicle speed difference of 10km/h is 0.5-1.0 m/s2T. The acceleration rate interval is a range of acceleration rates that the passenger can endure and feel comfortable.
2) Applying a predetermined plurality of braking force variations to the vehicle one by oneAnd a rate detecting unit configured to detect a rate of change of acceleration of the vehicle for each rate of change of the braking force. For example, the four braking force change rates are set as: 1000. 2000, 3000, 4000N/t. An acceleration detecting device is mounted in a vehicle, and when the vehicle is applied with braking force change rates of 1000, 2000, 3000 and 4000N/t, the acceleration change rates of the vehicle are respectively 0.4, 0.5, 0.7 and 0.8m/s2·t。
3) And determining the change rate of the braking force corresponding to the current vehicle speed, the target vehicle speed and the difference value of the current vehicle speed according to the change rate of the braking force of which the corresponding change rate of the acceleration is within the set acceleration change rate interval. The correspondence may be preset and stored. For example, several feature points in the corresponding relationship can be determined by a test method, and then the corresponding relationship is obtained by curve fitting through a correlation technique. In determining the feature point, the rate of change of the corresponding braking force may be determined so that the rate of change of the braking force can make the passenger feel comfortable at the current vehicle speed and the target vehicle speed. As exemplified above, the acceleration rates are 0.5, 0.7, 0.8m/s2The change rates of the braking force t are 2000, 3000, and 4000N/t, respectively. And determining the change rate of the braking force corresponding to the current vehicle speed of 30km/h and the vehicle speed difference of 10km/h according to the change rates of the three braking forces.
In this step, alternatively, when only one of the rates of change of the braking force is within the set acceleration rate change interval, the rate of change of the braking force is determined as the rate of change of the braking force corresponding to both the current vehicle speed, the target vehicle speed, and the difference value between the current vehicle speeds. For example, when the current vehicle speed is 30km/h and the difference between the current vehicle speeds is 10km/h, the change rates of the acceleration corresponding to the change rates of the braking force of 1000, 2000, 3000 and 4000N/t are respectively 0.4, 0.6, 0.7 and 0.8m/s2T, assuming that the section of the acceleration change rate set at this time is 0.3 to 0.5m/s2T, only the acceleration change rate 0.4 corresponding to 1000N/t is in the set acceleration change rate interval, and at this time, 1000N/t can be selected as the change rate of the braking force corresponding to the current vehicle speed of 30km/h and the vehicle speed difference of 10 km/h.
With a plurality of variations of braking forceWhen the rate is within the set acceleration rate change interval, the rate of change of the braking force corresponding to the difference between the current vehicle speed, the target vehicle speed, and the current vehicle speed is determined by averaging or averaging the rates of change of the plurality of braking forces. For example, when the braking force changes at rates of 2000, 3000, and 4000N/t, the acceleration changes at rates of 0.5, 0.7, and 0.8m/s2T, assuming that the section of the acceleration change rate set at this time is 0.5 to 1.0m/s2T, the change rate of the three accelerations is 0.5-1.0 m/s2T is in the range of 0.7m/s, which is the median value2The braking force change rate 3000N/t corresponding to t is taken as the braking force change rate corresponding to the current vehicle speed of 30km/h and the vehicle speed difference of 10 km/h.
4) And fitting a braking force change rate correlation data curve according to the determined multiple groups of different current vehicle speeds, target vehicle speeds and current vehicle speed difference values and the corresponding numerical values of the change rates of the braking force. The rate of change correlation data curve may be fitted, for example, by a least squares method, an averaging method, or an interpolation method.
5) The change rate-related data is obtained from the braking force change rate-related data curve.
The braking force change rate is determined by directly searching the change rate related data, so that the method is simple, high in speed and not prone to errors.
The target vehicle speed may be determined with reference to a vehicle speed desired by the user, thereby increasing the initiative of the passenger. In an embodiment of the present disclosure, on the basis of fig. 1, the step of determining the target vehicle speed of the vehicle on the current road surface downhill (step S1) may include:
in step S11, a desired vehicle speed of the vehicle on the current road surface downhill is acquired.
And step S12, determining the maximum vehicle speed allowed by the current road surface downhill.
In step S13, the vehicle speed value that is the smallest of the desired vehicle speed, the allowable maximum vehicle speed, and the current vehicle speed is determined as the target vehicle speed.
The desired vehicle speed reflects the intention of the driver, and may be set by the driver or determined according to the driving habits of the driver. The maximum vehicle speed allowed by the current downhill road can be preset or can be determined in real time according to the road condition information of the current road. The target vehicle speed should be less than or equal to the maximum vehicle speed allowed by the downhill of the current road surface, so that the safe running of the vehicle can be ensured. If the current vehicle speed is the minimum of the three, the vehicle does not need to accelerate downhill, and passengers can have better riding experience as long as the current vehicle speed is maintained.
In this embodiment, the target vehicle speed is selected from the three of the desired vehicle speed, the maximum allowable vehicle speed, and the current vehicle speed, which makes the vehicle travel more stably and the passenger more comfortable, while ensuring safety.
In an embodiment, the current desired vehicle speed may be set by the driver, and the step S11 may include the following steps:
in step S111, a setting command including a desired vehicle speed is received. The set command may be a message including a desired vehicle speed, for example, entered at a display interface after the driver turns on the downhill assist control system.
And step S112, when a setting instruction is received, determining a desired vehicle speed according to the setting instruction, and storing the friction coefficient and the gradient of the current road surface in a correlation manner with the desired vehicle speed contained in the setting instruction. In this way, upon determining the current desired vehicle speed, the desired vehicle speed is correlated with both the coefficient of friction and the gradient of the current road surface, and stored as historical data of the desired vehicle speed. The coefficient of friction and the gradient of the road surface can be detected by associated sensors.
In another embodiment, if the driver does not set the current desired vehicle speed, historical data or the vehicle speed at which the downhill assist control system is triggered may be used as the desired vehicle speed. In an embodiment, the step S11 may include the step S113.
And step S113, when the setting instruction is not received, searching the stored expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface, and if the expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface is not searched, determining the vehicle speed when the downhill auxiliary control system is triggered as the expected vehicle speed.
When the stored expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface is found, the historical data of the expected vehicle speed can be used as the current expected vehicle speed. The history of the desired vehicle speed represents the driving habit of the driver, and therefore, the current desired vehicle speed is close to the intention of the driver. If the historical data of the expected vehicle speed is not found, the vehicle speed when the downhill auxiliary control system is triggered is used as the expected vehicle speed, and the change of the vehicle speed is reduced as much as possible, so that the comfort of passengers is better.
The maximum allowable vehicle speed may be a predetermined value or may be determined in real time. In one embodiment, the step of determining the maximum vehicle speed allowed by the current road surface downhill (step S12) comprises the steps of:
in step S121, the friction coefficient and the gradient of the current road surface are acquired. The coefficient of friction and the gradient of the road surface can be detected by associated sensors.
In step S122, the allowable maximum vehicle speed corresponding to both the friction coefficient and the gradient of the current road surface is found out from the prestored maximum vehicle speed related data.
The maximum vehicle speed related data includes a correspondence relationship among a friction coefficient of a road surface, a gradient, and an allowable maximum vehicle speed. The corresponding maximum allowable vehicle speed may be obtained empirically or experimentally when both the coefficient of friction and the gradient of the road surface are determined. When the maximum vehicle speed related data is obtained in advance, a plurality of feature points can be obtained according to a test, and then a curve representing the corresponding relation among the friction coefficient, the gradient and the allowed maximum vehicle speed of the road surface can be determined in a common curve fitting mode. Thus, the maximum allowable vehicle speed under normal road conditions can be found in the curve.
In the embodiment, the allowable maximum vehicle speed is determined by adopting a searching mode, the calculation is simple, the speed is high, and errors are not easy to occur.
In the related art, when the driver depresses the brake pedal while the downhill assist control system is operating, the downhill assist control system is caused to stop operating regardless of whether the braking force corresponding to the brake pedal is large or small. In the present disclosure, the downhill assist control system may be taken out of operation only when the braking force corresponding to the brake pedal is greater than the current braking force. In this embodiment, on the basis of fig. 1, the step of controlling the braking force of the vehicle according to the determined rate of change of the braking force (step S3) may further include the following steps.
In step S31, the braking force corresponding to the brake pedal of the vehicle is detected.
And step S32, when the braking force corresponding to the brake pedal of the vehicle is smaller than the current braking force, controlling the braking force provided by the downhill auxiliary control system to control the vehicle.
And step S33, when the braking force corresponding to the brake pedal of the vehicle is larger than the current braking force, controlling the braking force provided by the brake pedal to control the vehicle.
In this embodiment, when the braking force corresponding to the brake pedal is smaller than the current braking force, the downhill assist control system is not exited, but the braking force corresponding to the brake pedal is ignored. And when the braking force corresponding to the brake pedal is greater than the current braking force, the downhill auxiliary control system is quitted. Therefore, the larger braking force of the braking force corresponding to the brake pedal and the current braking force controlled by the downhill auxiliary control system is applied to the vehicle, so that the driving safety of the vehicle is guaranteed, unnecessary vehicle speed change of the vehicle is avoided, and the comfort of passengers is enhanced.
It will be appreciated by those skilled in the art that the features of the above embodiments may be combined with each other without contradiction. Fig. 2 is a flowchart of a downhill assist control method according to another exemplary embodiment. In this embodiment, the above-described embodiments are combined.
In addition, in the related art, when the vehicle speed is greater than a predetermined vehicle speed threshold, the downhill assist control system cannot be entered. In the embodiment of the present disclosure, the upper limit of the vehicle speed triggered by the downhill assist control system may not be set. That is, the driver can turn on the downhill assist control system by pressing the on button regardless of the magnitude of the vehicle speed. Therefore, the vehicle can run at a safer speed through the operation of the downhill auxiliary control system, and the running safety of the vehicle is enhanced.
The present disclosure also provides a downhill assist control device. Fig. 3 is a block diagram of a downhill assist control device according to an exemplary embodiment. As shown in fig. 3, the downhill assist control device 10 may include a target vehicle speed determination module 11, a braking force change rate determination module 12, and a braking force control module 13.
The target vehicle speed determination module 11 is used for determining the target vehicle speed of the vehicle at the downhill of the current road surface.
The braking force change rate determination module 12 is connected to the target vehicle speed determination module 11 and is configured to determine a change rate of the braking force according to a current vehicle speed of the vehicle, a target vehicle speed, and a difference value between the current vehicle speed and the target vehicle speed.
The braking force control module 13 is connected to the braking force change rate determination module 12 for controlling the braking force of the vehicle in accordance with the determined rate of change of the braking force.
Alternatively, the braking force change rate determination module 12 may include a braking force change rate lookup sub-module.
The braking force change rate searching submodule is used for searching the braking force change rate corresponding to the current vehicle speed of the vehicle, the difference value of the target vehicle speed and the current vehicle speed in the prestored change rate related data.
Wherein the rate of change associated data is generated by:
setting an acceleration change rate interval corresponding to the current vehicle speed, the difference value of the target vehicle speed and the current vehicle speed; applying a plurality of predetermined braking force change rates to the vehicle one by one, and detecting a change rate of the acceleration of the vehicle corresponding to each braking force change rate; determining the change rate of the braking force corresponding to the difference value of the current vehicle speed, the target vehicle speed and the current vehicle speed according to the change rate of the braking force of which the corresponding change rate of the acceleration is within the set acceleration change rate interval; fitting a braking force change rate correlation data curve according to the determined values of the difference values of the plurality of groups of different current vehicle speeds, the target vehicle speed and the current vehicle speed and the corresponding change rate of the braking force; and obtaining the change rate related data through the braking force change rate related data curve.
Optionally, the target vehicle speed determination module 11 includes a desired vehicle speed acquisition sub-module, a maximum vehicle speed determination sub-module, and a target vehicle speed determination sub-module.
The expected vehicle speed obtaining submodule is used for obtaining the expected vehicle speed of the vehicle on the current road surface downhill.
The maximum vehicle speed determination submodule is used for determining the maximum vehicle speed allowed by the current downhill road.
And the target vehicle speed determining submodule is respectively connected with the expected vehicle speed obtaining submodule and the maximum vehicle speed determining submodule and is used for determining the vehicle speed value of one of the expected vehicle speed, the allowed maximum vehicle speed and the current vehicle speed with the minimum value as the target vehicle speed.
Optionally, the maximum allowable vehicle speed is a predetermined value, or the maximum vehicle speed determination sub-module includes a coefficient of friction and grade acquisition sub-module and a maximum vehicle speed lookup sub-module.
The friction coefficient and gradient obtaining submodule is used for obtaining the friction coefficient and the gradient of the current road surface.
And the maximum vehicle speed searching submodule is connected with the friction coefficient and gradient obtaining submodule and is used for searching the allowable maximum vehicle speed corresponding to the friction coefficient and the gradient of the current road surface in the prestored maximum vehicle speed related data.
Optionally, the desired vehicle speed acquisition submodule includes a receiving submodule and a first desired vehicle speed determination submodule.
The receiving submodule is used for receiving a setting instruction containing the expected vehicle speed.
The first expected vehicle speed determining submodule is connected with the receiving submodule and used for determining expected vehicle speed according to a set instruction when the set instruction is received, and storing the friction coefficient and the gradient of the current road surface and the expected vehicle speed contained in the set instruction in a correlation mode.
Optionally, the desired vehicle speed acquisition submodule may include a second desired vehicle speed determination submodule.
And the second expected vehicle speed determining submodule is used for searching the stored expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface when the setting instruction is not received, and determining the vehicle speed when the downhill auxiliary control system is triggered as the expected vehicle speed if the expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface is not searched.
Optionally, the braking force control module further comprises a detection submodule, a first control submodule and a second control submodule.
The detection submodule is used for detecting the braking force corresponding to the brake pedal of the vehicle.
The first control submodule is connected with the detection submodule and used for controlling the braking force provided by the downhill auxiliary control system to control the vehicle when the braking force corresponding to the brake pedal of the vehicle is smaller than the current braking force.
The second control submodule is connected with the detection submodule and used for controlling the braking force provided by the brake pedal to control the vehicle when the braking force corresponding to the brake pedal of the vehicle is larger than the current braking force.
With regard to the apparatus in the above embodiments, the specific manner in which each module performs operations has been described in detail in the embodiments related to the method, and will not be described in detail here.
According to the technical scheme, the change rate of the braking force of the vehicle when the current road surface is on the downhill is determined according to the current vehicle speed, the target vehicle speed and the difference value of the current vehicle speed. In this way, the braking force can be adjusted in consideration of the comfort of the occupant in controlling the braking of the vehicle. Compared with the technology of controlling the braking of the vehicle by the braking force with the preset magnitude, the technology of the present disclosure increases the stability of the whole vehicle and reduces the discomfort of passengers when the vehicle travels downhill.
The present disclosure also provides a vehicle including the downhill assist control device 10 described above.
The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, various possible combinations will not be separately described in this disclosure.
In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.
Claims (17)
1. A downhill assist control method, characterized by comprising:
determining a target vehicle speed of a vehicle on a current road surface downhill;
determining a rate of change of braking force according to a current vehicle speed of the vehicle, the target vehicle speed, and a difference value of the current vehicle speed;
controlling the braking force of the vehicle according to the determined rate of change of the braking force.
2. The method of claim 1, wherein the step of determining a rate of change of the braking force based on both a current vehicle speed of the vehicle, the target vehicle speed, and a difference value of the current vehicle speed comprises:
searching for a change rate of the braking force corresponding to a current vehicle speed of the vehicle, a difference between the target vehicle speed and the current vehicle speed in the change rate related data stored in advance,
wherein the rate of change associated data is generated by:
setting an acceleration change rate interval corresponding to the current vehicle speed, the difference value of the target vehicle speed and the current vehicle speed;
applying a plurality of predetermined braking force change rates to the vehicle one by one, and detecting a change rate of the acceleration of the vehicle corresponding to each braking force change rate;
determining the change rate of the braking force corresponding to the difference value of the current vehicle speed, the target vehicle speed and the current vehicle speed according to the change rate of the braking force of which the corresponding change rate of the acceleration is within the set acceleration change rate interval;
fitting a braking force change rate correlation data curve according to the determined values of the difference values of the plurality of groups of different current vehicle speeds, the target vehicle speed and the current vehicle speed and the corresponding change rate of the braking force;
and obtaining the change rate related data through the braking force change rate related data curve.
3. The method according to claim 2, wherein the step of determining the rate of change of the braking force corresponding to both the current vehicle speed, the target vehicle speed, and the current vehicle speed from the rate of change of the braking force whose corresponding rate of change of acceleration is within the set acceleration rate change interval includes:
when only one of the rates of change of the braking force is within the set acceleration rate change interval, determining the rate of change of the braking force as the rate of change of the braking force corresponding to the current vehicle speed, the difference value between the target vehicle speed and the current vehicle speed;
and when the change rates of the plurality of braking forces are within the set acceleration change rate interval, determining the change rate of the braking force corresponding to the current vehicle speed, the difference value of the target vehicle speed and the current vehicle speed by carrying out an average value method or a median value method on the change rates of the plurality of braking forces.
4. The method of claim 2, wherein the step of fitting a braking force rate of change associated data curve based on the determined plurality of different sets of values of the current vehicle speed, the target vehicle speed, and the current vehicle speed difference and the corresponding rate of change of the braking force comprises:
and fitting the braking force change rate associated data curve by a least square method, an averaging method or an interpolation method according to the determined values of the difference values of the plurality of different groups of the current vehicle speed, the target vehicle speed and the current vehicle speed and the corresponding change rate of the braking force.
5. The method of claim 1, wherein the step of determining a target vehicle speed for the vehicle on a current road downhill slope comprises:
acquiring the expected speed of the vehicle on the current road surface downhill;
determining the maximum vehicle speed allowed by the current road surface downhill;
and determining the vehicle speed value of one of the expected vehicle speed, the allowed maximum vehicle speed and the current vehicle speed with the minimum value as the target vehicle speed.
6. The method of claim 5, wherein the step of determining the maximum vehicle speed allowed for the current downhill slope comprises:
acquiring the friction coefficient and the gradient of the current road surface;
in the previously stored maximum vehicle speed-related data, an allowable maximum vehicle speed corresponding to both the friction coefficient and the gradient of the current road surface is found.
7. The method of claim 5, wherein the step of obtaining a desired vehicle speed for the vehicle on a current road downhill slope comprises:
receiving a setting instruction containing a desired vehicle speed;
and when the setting instruction is received, determining the expected vehicle speed according to the setting instruction, and storing the friction coefficient and the gradient of the current road surface in a correlation manner with the expected vehicle speed contained in the setting instruction.
8. The method of claim 7, wherein the step of obtaining a desired vehicle speed for the vehicle on a current road downhill slope further comprises:
and when the setting instruction is not received, searching the stored expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface, and if the expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface is not searched, determining the vehicle speed when the downhill auxiliary control system is triggered as the expected vehicle speed.
9. The method of any of claims 1-8, wherein the step of controlling the braking force of the vehicle in accordance with the determined rate of change of the braking force further comprises:
detecting a braking force corresponding to a brake pedal of the vehicle;
when the braking force corresponding to the brake pedal of the vehicle is smaller than the current braking force, controlling the braking force provided by the downhill auxiliary control system to control the vehicle;
and when the braking force corresponding to the brake pedal of the vehicle is greater than the current braking force, controlling the braking force provided by the brake pedal to control the vehicle.
10. A downhill assist control device, characterized in that the device comprises:
the target vehicle speed determining module is used for determining the target vehicle speed of the vehicle on the current road surface downhill;
the braking force change rate determining module is connected with the target vehicle speed determining module and used for determining the change rate of the braking force according to the current vehicle speed of the vehicle, the difference value of the target vehicle speed and the current vehicle speed;
and the braking force control module is connected with the braking force change rate determination module and is used for controlling the braking force of the vehicle according to the determined braking force change rate.
11. The apparatus of claim 10, wherein the braking force rate of change determination module comprises:
a braking force change rate search submodule for searching for a braking force change rate corresponding to a current vehicle speed of the vehicle, a difference between the target vehicle speed and the current vehicle speed from pre-stored change rate related data,
wherein the rate of change associated data is generated by:
setting an acceleration change rate interval corresponding to the current vehicle speed, the difference value of the target vehicle speed and the current vehicle speed;
applying a plurality of predetermined braking force change rates to the vehicle one by one, and detecting a change rate of the acceleration of the vehicle corresponding to each braking force change rate;
determining the change rate of the braking force corresponding to the difference value of the current vehicle speed, the target vehicle speed and the current vehicle speed according to the change rate of the braking force of which the corresponding change rate of the acceleration is within the set acceleration change rate interval;
fitting a braking force change rate correlation data curve according to the determined values of the difference values of the plurality of groups of different current vehicle speeds, the target vehicle speed and the current vehicle speed and the corresponding change rate of the braking force;
and obtaining the change rate related data through the braking force change rate related data curve.
12. The apparatus of claim 10, wherein the target vehicle speed determination module comprises:
the expected vehicle speed obtaining submodule is used for obtaining the expected vehicle speed of the vehicle on the current road surface downhill;
the maximum vehicle speed determining submodule is used for determining the maximum vehicle speed allowed by the current road surface downhill;
and the target vehicle speed determining submodule is respectively connected with the expected vehicle speed obtaining submodule and the maximum vehicle speed determining submodule and is used for determining the vehicle speed value of one of the expected vehicle speed, the allowed maximum vehicle speed and the current vehicle speed with the minimum value as the target vehicle speed.
13. The apparatus of claim 12, wherein the maximum vehicle speed determination submodule comprises:
the friction coefficient and gradient obtaining submodule is used for obtaining the friction coefficient and the gradient of the current road surface;
and the maximum vehicle speed searching submodule is connected with the friction coefficient and gradient obtaining submodule and is used for searching the allowable maximum vehicle speed corresponding to the friction coefficient and the gradient of the current road surface in the prestored maximum vehicle speed related data.
14. The apparatus of claim 12, wherein the desired vehicle speed acquisition submodule comprises:
the receiving submodule is used for receiving a setting instruction containing the expected vehicle speed;
and the first expected vehicle speed determining submodule is connected with the receiving submodule and used for determining the expected vehicle speed according to the setting instruction when the setting instruction is received, and storing the friction coefficient and the gradient of the current road surface and the expected vehicle speed contained in the setting instruction in an associated manner.
15. The apparatus of claim 14, wherein the desired vehicle speed acquisition submodule comprises:
and the second expected vehicle speed determining submodule is used for searching the stored expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface when the setting instruction is not received, and determining the vehicle speed when the downhill auxiliary control system is triggered as the expected vehicle speed if the expected vehicle speed corresponding to the friction coefficient and the gradient of the current road surface is not searched.
16. The apparatus of any of claims 10-15, wherein the braking force control module further comprises:
the detection submodule is used for detecting the braking force corresponding to a brake pedal of the vehicle;
the first control submodule is connected with the detection submodule and used for controlling the braking force provided by the downhill auxiliary control system to control the vehicle when the braking force corresponding to the brake pedal of the vehicle is smaller than the current braking force;
and the second control submodule is connected with the detection submodule and used for controlling the braking force provided by the brake pedal to control the vehicle when the braking force corresponding to the brake pedal of the vehicle is greater than the current braking force.
17. A vehicle comprising the apparatus of any of claims 10-16.
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| DE102007009860B4 (en) * | 2007-02-28 | 2022-05-25 | Zf Active Safety Gmbh | Method and device for speed control when driving downhill |
| JP6018018B2 (en) * | 2013-06-04 | 2016-11-02 | ダイムラー・アクチェンゲゼルシャフトＤａｉｍｌｅｒ ＡＧ | Electric vehicle regeneration control device |
| GB2519533B (en) * | 2013-10-23 | 2018-04-04 | Jaguar Land Rover Ltd | Vehicle speed control system |
| CN104843009B (en) * | 2014-12-04 | 2017-12-08 | 北汽福田汽车股份有限公司 | Vehicle descending accessory system, method and the vehicle comprising the system |
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