CN114684139A - Gear shifting control method and system based on intelligent driving - Google Patents

Gear shifting control method and system based on intelligent driving Download PDF

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Publication number
CN114684139A
CN114684139A CN202210330552.3A CN202210330552A CN114684139A CN 114684139 A CN114684139 A CN 114684139A CN 202210330552 A CN202210330552 A CN 202210330552A CN 114684139 A CN114684139 A CN 114684139A
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China
Prior art keywords
vehicle speed
torque
engine
braking
control method
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Pending
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CN202210330552.3A
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Chinese (zh)
Inventor
程志勇
程梁柱
杜绍宣
刘勰
赵佳丽
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Dongfeng Motor Corp
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Dongfeng Motor Corp
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Priority to CN202210330552.3A priority Critical patent/CN114684139A/en
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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
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units, or advanced driver assistance systems for ensuring comfort, stability and safety or drive control systems for propelling or retarding the vehicle
    • B60W30/18—Propelling the vehicle
    • B60W30/19—Improvement of gear change, e.g. by synchronisation or smoothing gear shift
    • 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
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/10—Conjoint control of vehicle sub-units of different type or different function including control of change-speed gearings
    • B60W10/11—Stepped gearings
    • 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
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/18—Conjoint control of vehicle sub-units of different type or different function including control of braking systems
    • 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
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units, or advanced driver assistance systems for ensuring comfort, stability and safety or drive control systems for propelling or retarding the vehicle
    • B60W30/14—Adaptive cruise control
    • B60W30/143—Speed control
    • 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
    • B60W2552/00—Input parameters relating to infrastructure
    • B60W2552/15—Road slope
    • 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
    • B60W2720/00—Output or target parameters relating to overall vehicle dynamics
    • B60W2720/10—Longitudinal speed

Abstract

The invention discloses a gear shifting control method based on intelligent driving, which is characterized in that based on a vehicle motion equation, wheel end torque required by maintaining a target vehicle speed in a downhill mode is calculated; calculating the working condition of the engine for maintaining the current vehicle speed in different gears based on the calibration data of the power assembly; when extra braking force is required to be applied, the vehicle speed control is finished in a control mode of combining downshift and drag and braking of a braking system, and the control method comprises the following specific steps: based on an engine mechanical loss test, acquiring engine mechanical loss torque under the working condition of the engine; calculating the wheel end dragging moment; acquiring gear information that the wheel end dragging torque is smaller than the required wheel end torque; selecting a proper gear to perform back-dragging control; and calculating the additional braking torque required to be applied, and sending a braking instruction to a braking system to enable the vehicle to maintain the target speed. The invention can effectively prolong the service life and improve the safety of the brake system.

Description

Gear shifting control method and system based on intelligent driving
Technical Field
The invention relates to an Adaptive Cruise Control (ACC), in particular to a gear shifting control method and system based on intelligent driving.
Background
In the ACC system, sensors such as radar and a camera measure information such as headway, relative speed, and relative acceleration between a host vehicle and a preceding vehicle, and provide the relevant information to an electronic control unit. The electric control unit determines the running state of the main vehicle according to the safe vehicle distance and the cruising running speed set by the driver and by combining the information transmitted by the radar.
1) When no running vehicle is in front of the vehicle, the vehicle is in a normal cruising running state, and the electronic control unit can realize an automatic control function by controlling the power output of the electronic throttle of the engine to the whole vehicle according to the set information.
2) When a target vehicle exists in front of the vehicle and the running speed of the target vehicle is smaller than the set speed, the electronic control unit calculates the ratio of the real vehicle distance to the safe vehicle distance and the relative speed, and appropriately brakes the wheels and reduces the output power of the engine through the coordination with the anti-lock braking system and the engine control system, so that the safe distance is always kept between the wheels and the front vehicle.
When the vehicle is in ACC self-adaptive cruise, because the braking force is provided by the braking system to perform deceleration control, under the control mode, when the vehicle is in a downhill process, particularly when a slope is too large, a large braking force needs to be applied for a long time to keep the target vehicle speed, so that excessive abrasion of the braking system can be caused, even the braking system can be failed, and traffic accidents can be caused.
Disclosure of Invention
The main purposes of the invention are as follows: the gear shifting control method and system based on intelligent driving are provided, and safety of intelligent driving is improved.
The technical scheme adopted by the invention is as follows: a gear shifting control method based on intelligent driving comprises the following steps:
s1, acquiring the current gradient and the target vehicle speed;
s2, calculating the wheel end torque T required by maintaining the target vehicle speed on the downhill based on the vehicle motion equationw；
S3, calculating the engine working conditions for maintaining the current vehicle speed in different gears based on the powertrain calibration data;
s4, when extra braking force is needed, the vehicle speed control is finished through a control mode combining downshifting and dragging and braking of a braking system, and the control method specifically comprises the following steps:
s401, acquiring a mechanical loss torque of the engine under the working condition of the engine based on a mechanical loss test of the engine;
s402, calculating a wheel end dragging torque based on the engine torque and the transmission speed ratio;
s403, gear information that the wheel end dragging torque is smaller than the required wheel end torque is obtained; based on the comfort requirement, selecting a proper gear and sending the gear to an automatic gearbox controller for carrying out back-dragging control;
s404, calculating extra braking torque to be applied based on the back-dragging torque of the selected gear and the required wheel end torque, sending a braking instruction to a braking system, and increasing corresponding extra braking force to enable the vehicle to maintain the target speed.
According to the method, the current gradient data is obtained through a high-precision map or a vehicle body sensor.
According to the method, the target speed is obtained by calculating the road speed limit information, the vehicle internal parameters and the front vehicle speed.
According to the method, the S2 specifically comprises the following steps:
Figure BDA0003572884320000021
in the formula uaTarget vehicle speed, G is vehicle gravity, f is rolling resistance coefficient, theta is gradient, CDThe coefficient of the air resistance of the automobile, A is the windward area, m is the automobile mass, delta is the conversion coefficient of the automobile rotating mass after the inertia moment of the rotating mass is counted, du/dt is the acceleration of the automobileAnd (4) degree.
According to the method, the S3 specifically comprises the following steps:
the power assembly calibration data comprises a gradient preset value and a vehicle speed preset value;
when the gradient is less than or equal to the preset gradient value or the vehicle speed is greater than or equal to the preset vehicle speed value, TwIf the power is positive, the control is carried out according to the normal power output;
when the gradient is larger than the preset gradient value or the vehicle speed is smaller than the preset vehicle speed value, TwIf the vehicle speed is negative, additionally applying a braking force to maintain the target vehicle speed;
based on the vehicle speed and the speed ratio of a transmission system, the engine rotating speeds at the current gear and the following gears are calculated when the target vehicle speed is calculated, and the formula is as follows:
ua＝60ueiπrw/1000igii0
wherein u isaIs a target vehicle speed ueIs the engine speed, rwIs the radius of the tire, igTo the transmission ratio, i0For final reduction ratio, the index i is used to distinguish gears.
According to the method, the step S401 specifically includes: based on different engine speeds ueWorking conditions, the mechanical loss of the engine is obtained through tests, and further the mechanical loss torque T of the engine is obtainede。
According to the above method, the step S402 specifically includes: based on the transmission speed ratios of different gears, the vehicle wheel end drag torque is obtained through calculation, and the formula is as follows:
T′w＝Teigi0ηT
wherein T'wFor wheel-end drag torque, TeFor mechanical loss torque of the engine, igTo the transmission ratio, i0Is a main reduction ratio, ηTFor transmission efficiency.
According to the method, S403, based on the comfort requirement, selects the wheel end torque T less than or equal to the required valuewThe maximum drag torque gear.
According to the method, the steps S1-S4 are iteratively calculated, and the gear and the braking force are adjusted, so that the target vehicle speed is automatically maintained.
The system is arranged in an intelligent driving control system, is connected with a vehicle sensing system and used for acquiring a current gradient and a target vehicle speed, is connected with an automatic gearbox controller and used for sending a gear shifting command, and is connected with a braking system and used for sending a braking command, so that the gear shifting control method based on intelligent driving is completed.
The invention has the following beneficial effects:
1. when additional braking force is required to be applied, the invention completes vehicle speed control in a control mode of combining downshift and drag and braking of the braking system, and finally the braking force required to be output by the braking system is far lower than the braking force required to be output when the downshift control is not performed by the vehicle through the drag torque generated by the applied downshift, thereby effectively prolonging the service life and improving the safety of the braking system.
2. When the downshift drag-down control is applied, the comfort requirement is considered, and the comfort of passengers is improved.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a flow chart of a method according to an embodiment of the present invention.
FIG. 2 is a flowchart of a method for downshifting, dragging, and braking by the braking system in accordance with an embodiment of the present invention.
Fig. 3 is a system block diagram of an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1, the present invention provides a shift control method based on smart driving, which includes the steps of:
and S1, acquiring the current gradient and the target vehicle speed.
The current grade data may be obtained from a high-precision map or body sensors. The target speed is obtained by calculating road speed limit information, vehicle internal parameters and the speed of a front vehicle.
S2, calculating the wheel end torque T required by maintaining the target vehicle speed on the downhill based on the vehicle motion equationwThe method specifically comprises the following steps:
Figure BDA0003572884320000041
in the formula uaTarget vehicle speed, G is vehicle gravity, f is rolling resistance coefficient, theta is gradient, CDThe coefficient is the air resistance coefficient of the automobile, A is the windward area, m is the automobile mass, delta is the conversion coefficient of the automobile rotating mass after the inertia moment of the rotating mass is counted, and du/dt is the automobile acceleration. f and δ are given values.
S3, calculating the engine working conditions for maintaining the current vehicle speed in different gears based on the powertrain calibration data; the method specifically comprises the following steps:
the power assembly calibration data comprises a gradient preset value and a vehicle speed preset value;
when the gradient is less than or equal to the preset gradient value or the vehicle speed is greater than or equal to the preset vehicle speed value, TwIf the power is positive, the control is carried out according to the normal power output;
when the gradient is larger than the preset gradient value or the vehicle speed is smaller than the preset vehicle speed value, TwIf the vehicle speed is negative, additionally applying a braking force to maintain the target vehicle speed;
based on the vehicle speed and the speed ratio of a transmission system, the engine rotating speeds at the current gear and the following gears are calculated when the target vehicle speed is calculated, and the formula is as follows:
ua＝60ueiπrw/1000igii0
wherein u isaIs a target vehicle speed ueIs the engine speed, rwIs the radius of the tire, igTo the transmission ratio, i0For final reduction ratio, the index i is used to distinguish gears.
And S4, when extra braking force is needed, controlling the vehicle speed in a control mode combining downshifting and dragging and braking of a braking system, as shown in FIG. 2, specifically as follows:
s401, acquiring mechanical loss torque of the engine under the working condition of the engine based on a mechanical loss test of the engine; based on different engine speeds ueWorking conditions, the mechanical loss of the engine is obtained through tests, and further the mechanical loss torque T of the engine is obtainede。
S402, calculating a wheel end dragging torque based on the engine torque and the transmission speed ratio; the method specifically comprises the following steps: based on the transmission speed ratios of different gears, the vehicle wheel end drag torque is obtained through calculation, and the formula is as follows:
T′w＝Teigi0ηT
wherein T'wFor wheel-end drag torque, TeFor mechanical loss torque of the engine, igTo the transmission ratio, i0Is a main reduction ratio, ηTFor transmission efficiency.
S403, gear information that the wheel end dragging torque is smaller than the required wheel end torque is obtained; based on the comfort requirement, selecting a proper gear to send to an automatic gearbox controller for carrying out dragging control, specifically, based on the comfort requirement, selecting the gear end torque T less than or equal to the required gear end torque TwThe maximum drag torque gear.
S404, calculating extra braking torque to be applied based on the back-dragging torque of the selected gear and the required wheel end torque, sending a braking instruction to a braking system, and increasing corresponding extra braking force to enable the vehicle to maintain the target speed.
And step S1-S4 are iteratively calculated, and the gear and the braking force are adjusted, so that the target vehicle speed is automatically maintained.
A gear shifting control system based on intelligent driving is arranged in an intelligent driving control system, is connected with a vehicle sensing system and used for obtaining a current gradient and a target vehicle speed, is connected with an automatic gearbox controller and used for sending a gear shifting command, and is connected with a braking system and used for sending a braking command, so that the gear shifting control method based on intelligent driving is completed.
The invention provides a novel intelligent driving control method, which is characterized in that the change of the gear position of a gearbox is intelligently controlled, the dragging torque generated by the engine dragging backwards is realized, the speed is controlled to be kept at the target speed under the combined action of a braking system, the risk of excessive abrasion and even failure of a brake pad caused by long-time braking is avoided, the safety of an intelligent driving function is greatly improved, and the practicability is high.
It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Claims (10)

1. A gear shifting control method based on intelligent driving is characterized by comprising the following steps:
s1, acquiring the current gradient and the target vehicle speed;
s2, calculating the wheel end torque T required by maintaining the target vehicle speed on the downhill based on the vehicle motion equationw；
S3, calculating the engine working conditions for maintaining the current vehicle speed in different gears based on the powertrain calibration data;
s4, when additional braking force is needed, the vehicle speed control is finished through a control mode of combining downshifting and dragging and braking of a braking system, and the control method comprises the following specific steps:
s401, acquiring a mechanical loss torque of the engine under the working condition of the engine based on a mechanical loss test of the engine;
s402, calculating a wheel end dragging torque based on the engine torque and the transmission speed ratio;
s403, gear information that the wheel end dragging torque is smaller than the required wheel end torque is obtained; based on the comfort requirement, selecting a proper gear and sending the gear to an automatic gearbox controller for carrying out back-dragging control;
s404, calculating extra braking torque to be applied based on the back-dragging torque of the selected gear and the required wheel end torque, sending a braking instruction to a braking system, and increasing corresponding extra braking force to enable the vehicle to maintain the target speed.
2. The shift control method based on smart driving according to claim 1, wherein the current gradient data is obtained through a high-precision map or a vehicle body sensor.
3. The shift control method based on intelligent driving according to claim 1, wherein the target vehicle speed is calculated from road speed limit information, in-vehicle parameters, and a preceding vehicle speed.
4. The shift control method based on smart driving according to claim 1, wherein S2 is specifically:
Figure FDA0003572884310000011
in the formula uaTarget vehicle speed, G is vehicle gravity, f is rolling resistance coefficient, theta is gradient, CDThe coefficient is the air resistance coefficient of the automobile, A is the windward area, m is the automobile mass, delta is the conversion coefficient of the automobile rotating mass after the inertia moment of the rotating mass is counted, and du/dt is the automobile acceleration.
5. The shift control method based on smart driving according to claim 1, wherein S3 is specifically:
the power assembly calibration data comprises a gradient preset value and a vehicle speed preset value;
when the gradient is less than or equal to the preset gradient value or the vehicle speed is greater than or equal to the preset vehicle speed value, TwIf the power is positive, the control is carried out according to the normal power output;
when the gradient is larger than the preset gradient value or the vehicle speed is smaller than the preset vehicle speed value, TwIf the vehicle speed is negative, additionally applying a braking force to maintain the target vehicle speed;
based on the vehicle speed and the speed ratio of a transmission system, the engine rotating speeds at the current gear and the following gears are calculated when the target vehicle speed is calculated, and the formula is as follows:
ua＝60ueiπrw/1000igii0
wherein u isaIs a target vehicle speed ueIs the engine speed, rwIs the radius of the tire, igTo the transmission ratio, i0For final reduction ratio, the index i is used to distinguish gears.
6. The shift control method based on intelligent driving according to claim 1, wherein S401 specifically is: based on different engine speeds ueWorking conditions, the mechanical loss of the engine is obtained through tests, and further the mechanical loss torque T of the engine is obtainede。
7. The shift control method based on smart driving according to claim 1, wherein S402 is specifically: based on the transmission speed ratios of different gears, the vehicle wheel end drag torque is obtained through calculation, and the formula is as follows:
T′w＝Teigi0ηT
wherein T'wFor wheel-end drag torque, TeFor mechanical loss torque of the engine, igTo the transmission ratio, i0Is a main reduction ratio, ηTFor transmission efficiency.
8. The shift control method based on smart driving according to claim 1, wherein the step S403 selects the wheel end torque T less than or equal to the required value based on the comfort requirementwThe maximum drag torque gear.
9. The shift control method based on smart driving of claim 1, wherein S1-S4 are iteratively calculated to adjust a shift position and a braking force, so as to automatically maintain a target vehicle speed.
10. The utility model provides a shift control system based on intelligent driving which characterized in that: the system is arranged in an intelligent driving control system, is connected with a vehicle sensing system to acquire a current gradient and a target vehicle speed, is connected with an automatic gearbox controller to send a gear shifting command, and is connected with a braking system to send a braking command to complete the intelligent driving-based gear shifting control method according to any one of claims 1 to 9.
CN202210330552.3A 2022-03-30 2022-03-30 Gear shifting control method and system based on intelligent driving Pending CN114684139A (en)

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Application Number Priority Date Filing Date Title
CN202210330552.3A CN114684139A (en) 2022-03-30 2022-03-30 Gear shifting control method and system based on intelligent driving

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210330552.3A CN114684139A (en) 2022-03-30 2022-03-30 Gear shifting control method and system based on intelligent driving

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CN114684139A true CN114684139A (en) 2022-07-01

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