CN113173177A - Control method and system of automatic driving safety redundancy mechanism based on differential braking - Google Patents
Control method and system of automatic driving safety redundancy mechanism based on differential braking Download PDFInfo
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- CN113173177A CN113173177A CN202110456184.2A CN202110456184A CN113173177A CN 113173177 A CN113173177 A CN 113173177A CN 202110456184 A CN202110456184 A CN 202110456184A CN 113173177 A CN113173177 A CN 113173177A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
- B60W50/02—Ensuring safety in case of control system failures, e.g. by diagnosing, circumventing or fixing failures
- B60W50/029—Adapting to failures or work around with other constraints, e.g. circumvention by avoiding use of failed parts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
- B60W50/02—Ensuring safety in case of control system failures, e.g. by diagnosing, circumventing or fixing failures
- B60W50/029—Adapting to failures or work around with other constraints, e.g. circumvention by avoiding use of failed parts
- B60W2050/0292—Fail-safe or redundant systems, e.g. limp-home or backup systems
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- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Human Computer Interaction (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Regulating Braking Force (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
Abstract
The invention discloses a control method and a system of an automatic driving safety redundancy mechanism based on differential braking, and relates to the technical field of automatic driving. The invention comprises the following steps: step S1: turning on the power supply of the vehicle, and starting the system to run and perform self-checking; step S2: running and calculating in real time according to the vehicle state, the environmental information and the path planning; step S3: detecting the working state of a vehicle steering system, and starting a differential braking steering control system when the vehicle steering system stops; step S4: tracking and comparing the real-time position and the planned path of the vehicle, and applying different braking forces to the left wheel and the right wheel of the vehicle by an execution module to control the motion path of the vehicle; step S5: the process ends when the vehicle reaches a safe parking position. The invention provides a control method and a system of an automatic driving safety redundancy mechanism based on differential braking, which can realize the adjustment of the moving direction of a vehicle by adjusting the braking force of wheels when a vehicle steering system fails, thereby greatly improving the safety factor of automatic driving.
Description
Technical Field
The invention belongs to the technical field of automatic driving, and particularly relates to a control method and a system of an automatic driving safety redundancy mechanism based on differential braking.
Background
Along with the development of unmanned technology, the automobile intelligence degree is continuously improved, and more electronic elements are arranged on the automobile. The main challenges of the automatic driving technology are to reduce the human participation in driving on one hand and to require the interaction of various types of sensors on the other hand, both factors greatly increasing the complexity of the system. Safety and reliability are the key of the automatic driving system. The steering control system is an important execution module for automatic driving, and if the steering system cannot work normally, a vehicle cannot realize expected steering operation and cannot run safely, the life safety of people is endangered, so that a safety redundancy mechanism of the steering system is of great importance. When the vehicle is in steering failure during running, the safety redundancy mechanism is used for ensuring that the vehicle reaches a safe state, and the safety redundancy mechanism has important significance.
The application of different braking forces to different wheels can very effectively change the yaw moment of the vehicle, thereby adjusting the motion attitude of the vehicle. The differential braking can play a role in braking, driving, steering or the composite working condition thereof, and particularly can effectively provide the yaw moment of the automobile to change the running posture of the automobile when the mass center side slip angle of the automobile is larger.
Disclosure of Invention
The invention aims to provide a control method and a system of an automatic driving safety redundancy mechanism based on differential braking to solve the problem of failure of a steering system. The method comprises the steps that the automobile monitors faults of an Electric Power Steering (EPS) system of the automobile in the running process, and when the EPS system is determined to be completely failed due to faults, a steering redundancy mechanism of differential braking is adopted, so that the automobile can be safely stopped as soon as possible, and a safe state is achieved. According to the current motion state information of the vehicle and the surrounding sensing environment information acquired by the sensor, a safe path is planned through the decision control module, the additional yaw moment of the left wheel and the additional yaw moment of the right wheel are calculated, the braking force required to be applied to the wheels of the vehicle is output, the vehicle is enabled to reach the expected motion attitude, and the vehicle is decelerated and stopped at a proper position. Meanwhile, the differential braking control algorithm can be self-adaptively learned according to the change of the load of the whole vehicle and the change of the tire pressure of the tire, so that the steering control precision of the current vehicle activated safety redundancy mechanism is improved.
In order to solve the technical problems, the invention is realized by the following technical scheme:
the invention relates to a control method of an automatic driving safety redundancy mechanism based on differential braking, which comprises the following steps:
step S1: turning on the power supply of the vehicle, and starting the system to run and perform self-checking;
step S2: running and calculating in real time according to the vehicle state, the environmental information and the path planning;
step S3: detecting the working state of a vehicle steering system, and starting a differential braking steering control system when the vehicle steering system stops;
step S4: tracking and comparing the real-time position and the planned path of the vehicle, and applying different braking forces to the left wheel and the right wheel of the vehicle by an execution module to control the motion path of the vehicle;
step S5: the process ends when the vehicle reaches a safe parking position.
Further, the step S4 specifically includes the following steps:
step S41: according to the vehicle condition information and the road condition, the vehicle model module calculates an expected yaw moment required by the vehicle for changing the path;
step S42: the braking pressure calculating and distributing module calculates braking forces required by the rotation of the left and right wheels according to the expected yaw moment of the vehicle;
step S43: and transmitting the operation result to an execution module to regulate and control the braking force applied to each wheel.
Further, the calculation formula of the yaw moment of the vehicle and the braking force exerted on the wheels at the two sides is as follows:
Fxr＝Fxfa/b
Fxr+Fxf＝ΔFx
probj＝Fxrr/Kbr
pfobj＝Fxfr/Kbf
in the formula, MzDesired yaw moment for vehicle, drIs the distance, Δ F, between the front and rear wheels on the same side of the vehiclexFor the total braking force of the vehicle, a, b are the distances from the center of mass to the front and rear axles, FxrA target side rear wheel longitudinal braking force; fxfThe longitudinal braking force of the front wheel on the target side is shown, and r is the radius of the wheel; kbfA front wheel braking effectiveness factor determined by the braking friction area, the friction factor and the brake radius; kbrIs a rear wheel braking effectiveness factor that is determined collectively by the braking friction area, the friction factor, and the brake radius.
Further, the execution module is used for regulating and controlling the real-time brake pressure of each wheel to ensure that the yaw moment generated by the vehicle is consistent with the calculated expected yaw moment.
The invention relates to a control system of an automatic driving steering safety redundancy mechanism based on differential braking, which is characterized by comprising a vehicle model module, a monitoring module, a braking pressure calculating and distributing module and an executing module.
Further, the vehicle model module is used for detecting the self state and road condition information of the current vehicle and calculating the expected yaw moment of the vehicle.
Further, the monitoring module is used for detecting the working state of the steering system and switching to a control system of an automatic driving safety redundancy mechanism of differential braking when the steering system cannot work normally.
Further, the brake pressure calculation and distribution module is used for calculating the brake pressure required by each wheel in the safe parking path according to the expected yaw moment and transmitting signals to the execution module.
Further, the execution module is used for controlling the braking force of the corresponding wheel.
The invention has the following beneficial effects:
the invention provides a control method and a system of an automatic driving safety redundancy mechanism based on differential braking, which can control the steering movement of a vehicle by crossing a steering system through a method of differential braking of wheels when the steering system of the vehicle fails, so that the vehicle reaches a safe state, and the safety of automatic driving is effectively improved.
Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of the architecture of the control method and system for the differential brake based autonomous driving safety redundancy mechanism of the present invention;
FIG. 2 is a schematic diagram of a control algorithm of the present invention;
FIG. 3 is a schematic illustration of a vehicle yaw moment;
FIG. 4 is a schematic view of a wheel under force;
in the drawings, the components represented by the respective reference numerals are listed below:
Fxrlleft rear wheel braking force, FxrrRight rear wheel braking force, FxflLeft front wheel braking force, Fxfr-right front wheel braking force.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "open," "upper," "lower," "disposed," "peripheral side," "inner," "outer," "symmetrical," "bottom," and the like are used in an orientation or positional relationship that is merely for convenience in describing and simplifying the description, and do not indicate or imply that the referenced components or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be considered as limiting the present invention.
Referring to fig. 1-2, the present invention is an automatic driving safety redundancy control system based on differential braking, comprising the following steps:
step S1: turning on the power supply of the vehicle, and starting the system to run and perform self-checking;
step S2: running and calculating in real time according to the vehicle state, the environmental information and the path planning;
step S3: detecting the working state of a vehicle steering system, and starting a differential braking steering control system when the vehicle steering system stops;
step S4: tracking and comparing the real-time position and the planned path of the vehicle, and applying different braking forces to the left wheel and the right wheel of the vehicle by an execution module to control the motion path of the vehicle;
step S5: the process ends when the vehicle reaches a safe parking position.
Wherein, step S4 specifically includes the following steps:
step S41: according to the vehicle condition information and the road condition, the vehicle model module calculates an expected yaw moment required by the vehicle for changing the path;
step S42: the braking pressure calculating and distributing module calculates braking forces required by the rotation of the left and right wheels according to the expected yaw moment of the vehicle;
step S43: and transmitting the operation result to an execution module to regulate and control the braking force applied to each wheel.
The calculation formulas of the yaw moment of the vehicle and the braking forces of the wheels on the two sides are as follows:
Fxr＝Fxfa/b
Fxr+Fxf＝ΔFx
probj＝Fxrr/Kbr
pfobj＝Fxfr/Kbf
in the formula, MzDesired yaw moment for vehicle, drIs the distance, Δ F, between the front and rear wheels on the same side of the vehiclexFor the total braking force of the vehicle, a, b are the distances from the center of mass to the front and rear axles, FxrA target side rear wheel longitudinal braking force; fxfThe longitudinal braking force of the front wheel on the target side is shown, and r is the radius of the wheel; kbfA front wheel braking effectiveness factor determined by the braking friction area, the friction factor and the brake radius; kbrIs a rear wheel braking effectiveness factor that is determined collectively by the braking friction area, the friction factor, and the brake radius.
The execution module is used for regulating and controlling the real-time brake pressure of each wheel so as to ensure that the yaw moment generated by the vehicle is consistent with the calculated expected yaw moment.
The control system of the automatic driving steering safety redundancy mechanism based on differential braking is characterized by comprising a vehicle model module, a monitoring module, a braking pressure calculating and distributing module and an executing module.
The vehicle model module is used for detecting the self state and road condition information of the current vehicle and calculating the expected yaw moment of the vehicle.
The monitoring module is used for detecting the working state of the steering system and switching to a control system of an automatic driving safety redundancy mechanism of differential braking when the steering system cannot work normally.
The braking pressure calculation and distribution module is used for calculating the braking pressure required by each wheel in the safe parking path according to the expected yaw moment and transmitting signals to the execution module; and the brake pressure calculating and distributing module can adapt to the change of the load and the tire pressure of the vehicle, and the precision of steering control is improved.
The execution module is used for controlling the braking force of the corresponding wheel.
One specific application of the invention is: when the invention is used, the monitoring module detects that the vehicle steering system is invalid and switches to a control system of an automatic driving safety redundancy mechanism of differential braking; the vehicle model module calculates an expected yaw moment of the vehicle moving to a safe position according to the self state and road condition information of the current vehicle; the brake pressure calculating and distributing module calculates the brake pressure required by each wheel in the safe parking path according to the expected yaw moment and transmits signals to the execution module; and the execution module adjusts the braking force applied to each wheel according to the received signals, so that the vehicle can safely drive to the calculated safe parking position.
In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims (9)
1. The control method of the automatic driving safety redundancy mechanism based on the differential braking is characterized by comprising the following steps:
step S1: turning on the power supply of the vehicle, and starting the system to run and perform self-checking;
step S2: running and calculating in real time according to the vehicle state, the environmental information and the path planning;
step S3: detecting the working state of a vehicle steering system, and starting a differential braking steering control system when the vehicle steering system stops;
step S4: tracking and comparing the real-time position and the planned path of the vehicle, and applying different braking forces to the left wheel and the right wheel of the vehicle by an execution module to control the motion path of the vehicle;
step S5: the process ends when the vehicle reaches a safe parking position.
2. The method for controlling a differential brake-based automated driving safety redundancy mechanism according to claim 1, wherein the step S4 specifically comprises the following steps:
step S41: according to the vehicle condition information and the road condition, the vehicle model module calculates an expected yaw moment required by the vehicle for changing the path;
step S42: the braking pressure calculating and distributing module calculates braking forces required by the rotation of the left and right wheels according to the expected yaw moment of the vehicle;
step S43: and transmitting the operation result to an execution module to regulate and control the braking force applied to each wheel.
3. The differential braking-based control method for the automated driving safety redundancy mechanism according to claim 2, wherein the calculation formula of the yaw moment of the vehicle and the braking force applied to the wheels at the two sides is as follows:
Fxr＝Fxfa/b
Fxr+Fxf＝ΔFx
probj＝Fxrr/Kbr
pfobj＝Fxfr/Kbf
in the formula, MzDesired yaw moment for vehicle, drIs the distance, Δ F, between the front and rear wheels on the same side of the vehiclexFor the total braking force of the vehicle, a, b are the distances from the center of mass to the front and rear axles, FxrA target side rear wheel longitudinal braking force; fxfThe longitudinal braking force of the front wheel on the target side is shown, and r is the radius of the wheel; kbfA front wheel braking effectiveness factor determined by the braking friction area, the friction factor and the brake radius; kbrIs a rear wheel braking effectiveness factor that is determined collectively by the braking friction area, the friction factor, and the brake radius.
4. The differential braking-based control method for an autonomous driving safety redundancy mechanism according to claim 2, characterized in that the implementation module is adapted to regulate the real-time brake pressure of each wheel to ensure that the yaw moment generated by the vehicle is consistent with the calculated desired yaw moment.
5. The control system of the automatic driving steering safety redundancy mechanism based on differential braking is characterized by comprising a vehicle model module, a monitoring module, a braking pressure calculating and distributing module and an executing module.
6. The differential braking-based control system for the redundant safety steering mechanism for automatic driving and steering according to claim 5, wherein the vehicle model module is configured to detect the current vehicle state and road condition information and calculate the desired yaw moment of the vehicle.
7. The differential braking-based control system for the automated driving steering safety redundancy mechanism according to claim 5, wherein the monitoring module is configured to detect an operating state of the steering system and switch to the differential braking-based control system for the automated driving safety redundancy mechanism when the steering system fails to operate normally.
8. The differential brake-based control system for an autonomous steering safety redundant mechanism according to claim 5, characterized in that the brake pressure calculation and distribution module is adapted to calculate the required brake pressure for each wheel in the safe parking path according to the desired yaw moment and to transmit a signal to the execution module.
9. The differential brake-based automated steering safety redundancy mechanism control system of claim 5, wherein the execution module is configured to control the braking force of the corresponding wheel.
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| CN202110456184.2A CN113173177A (en) | 2021-04-26 | 2021-04-26 | Control method and system of automatic driving safety redundancy mechanism based on differential braking |
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| CN202110456184.2A CN113173177A (en) | 2021-04-26 | 2021-04-26 | Control method and system of automatic driving safety redundancy mechanism based on differential braking |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114084158A (en) * | 2021-12-17 | 2022-02-25 | 吉林大学 | Automatic driving redundancy control system |
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| US6021367A (en) * | 1994-08-24 | 2000-02-01 | Ford Global Technologies, Inc. | Vehicle steering system and method for controlling vehicle direction through differential braking of left and right road wheels |
| CN102765386A (en) * | 2011-05-05 | 2012-11-07 | 通用汽车环球科技运作有限责任公司 | Lane centering fail-safe control using differential braking |
| CN109910883A (en) * | 2019-04-15 | 2019-06-21 | 一汽解放汽车有限公司 | The holding control device and its method of lane center with redundancy protecting |
| CN110015294A (en) * | 2019-04-15 | 2019-07-16 | 中国第一汽车股份有限公司 | Lane keeps control method |
| CN111137355A (en) * | 2018-11-02 | 2020-05-12 | 丹佛斯动力***公司 | Vehicle steering control system and method |
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2021
- 2021-04-26 CN CN202110456184.2A patent/CN113173177A/en not_active Withdrawn
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6021367A (en) * | 1994-08-24 | 2000-02-01 | Ford Global Technologies, Inc. | Vehicle steering system and method for controlling vehicle direction through differential braking of left and right road wheels |
| CN102765386A (en) * | 2011-05-05 | 2012-11-07 | 通用汽车环球科技运作有限责任公司 | Lane centering fail-safe control using differential braking |
| CN111137355A (en) * | 2018-11-02 | 2020-05-12 | 丹佛斯动力***公司 | Vehicle steering control system and method |
| CN109910883A (en) * | 2019-04-15 | 2019-06-21 | 一汽解放汽车有限公司 | The holding control device and its method of lane center with redundancy protecting |
| CN110015294A (en) * | 2019-04-15 | 2019-07-16 | 中国第一汽车股份有限公司 | Lane keeps control method |
Non-Patent Citations (1)
| Title |
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| 吴乙万等: "基于差动制动的车道偏离辅助控制", 《中国机械工程》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114084158A (en) * | 2021-12-17 | 2022-02-25 | 吉林大学 | Automatic driving redundancy control system |
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Application publication date: 20210727 |
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