CN110067852B - An adaptive cruise shift control method based on a dual-stage planetary two-speed transmission - Google Patents

Abstract

The invention discloses a self-adaptive cruise shift control method based on a two-stage planetary gear transmission, which comprises the following steps: step one, acquiring the speed of the vehicle, the opening degree of an accelerator, the mass of the vehicle, the speed of a front vehicle and the distance between the vehicle and the front vehicle, and determining a reference gear coefficient of the vehicle according to the speed of the vehicle, the opening degree of the accelerator, the mass of the vehicle, the speed of the front vehicle and the distance between the vehicle and the front vehicle; step two, acquiring outdoor environment temperature, humidity, road surface adhesion coefficient and outdoor light intensity, and determining the environment coefficient of vehicle running according to the outdoor environment temperature, humidity, road surface adhesion coefficient and outdoor light intensity; and step three, judging the proper gear of the vehicle in the current running state according to the reference gear index of the vehicle and the environment index of the running of the vehicle. The self-adaptive cruise shift control method based on the two-stage planetary gear transmission can assist a driver in determining correct shift time, and enables a vehicle to be kept in a high-efficiency working state.

Description

An adaptive cruise shift control method based on a dual-stage planetary two-speed transmission

Technical field

The invention belongs to the technical field of vehicle shift control, and particularly relates to an adaptive cruise shift control method based on a dual-stage planetary two-speed transmission.

Background technique

The development of the automobile industry has greatly polluted the human living environment, especially in big cities. The exhaust gas emitted by various motor vehicles has seriously harmed human health. This harm is particularly serious in industrially developed countries. The electric drive system does not emit any substances when working, that is, it has zero emissions and is environmentally friendly. Therefore, gradually replacing gasoline vehicles with electric vehicles is the direction of efforts of countries around the world today.

The automobile transmission is a transmission device used to coordinate the engine speed and the actual driving speed of the wheels to maximize the engine's performance. The transmission can produce different gear ratios between the engine and the wheels while the car is driving. By shifting gears, the engine can operate at its best power performance.

Two-speed transmissions for electric vehicles generally adopt a parallel shaft arrangement or a planetary gear arrangement. For two-speed transmissions with a planetary gear arrangement, gear switching is mostly achieved through a clutch or brake combination.

When the vehicle is driving, the driver needs to change gears according to the road surface to keep the vehicle in efficient working condition. However, during actual driving, some drivers are unable to accurately judge the timing of shifting due to lack of experience, resulting in low vehicle efficiency and high energy consumption.

Contents of the invention

The present invention provides an adaptive cruise shift control method based on a dual-stage planetary two-speed transmission. Its purpose is to determine the gear suitable for the current vehicle driving according to the road vehicle conditions and the driving environment, and to assist the driver in determining the correct gear shift. timing to keep the vehicle in efficient working condition.

The technical solution provided by the invention is:

An adaptive cruise shift control method based on a dual-stage planetary two-speed transmission, including:

Step 1: Obtain the speed of the own vehicle, the accelerator opening, the mass of the own vehicle, the speed of the preceding vehicle and the distance between the own vehicle and the preceding vehicle, and based on the speed of the own vehicle, the accelerator opening, the mass of the own vehicle, the speed of the preceding vehicle and The distance between the vehicle in front and the vehicle in front determines the vehicle’s base gear coefficient;

Step 2: Obtain the outdoor ambient temperature, humidity, road adhesion coefficient and outdoor light intensity, and determine the environmental coefficient for vehicle driving based on the outdoor ambient temperature, humidity, road adhesion coefficient and outdoor light intensity;

Step 3: Determine the appropriate gear of the vehicle in the current driving state based on the vehicle's reference gear index and the vehicle's driving environment index.

Preferably, the reference gear coefficient of the vehicle is:

Among them, ξ is the correction parameter; α is the throttle opening, α ₀ is the benchmark throttle opening; m is the vehicle mass, m ₀ is the benchmark vehicle mass; v is the speed of the own vehicle, v ₀ is the speed of the preceding vehicle; S is The distance between the vehicle in front and the vehicle in front, S ₀ is the reference distance between the vehicle in front and the vehicle in front; e is the base of the natural logarithm.

Preferably, the value of the correction parameter ξ is:

When v≤50Km/h, ξ=0.6;

When v>50Km/h, ξ=1.

Preferably, the environmental coefficient of the vehicle driving is:

Among them, a and b are correction parameters; μ is the road adhesion coefficient, RH is the relative humidity of the environment; RH ₀ is the relative humidity of the reference environment; T is the ambient temperature, T ₀ is the reference ambient temperature; I is the outdoor light intensity, and I ₀ is Baseline outdoor light intensity; e is the base of the natural logarithm.

Preferably, the values of the correction parameters a and b are respectively:

When RH<50%, a=0.6;

When RH≥50%, a=0.7; and

When T≤0℃, b=0.6;

When T>0℃, b=0.4.

Preferably, in step three, the current gear coefficient is determined based on the vehicle's reference gear coefficient and the vehicle's driving environment coefficient as:

χ=χ ₀ ·E;

Among them, when χ ≤ 0.5, it is judged that the appropriate gear of the vehicle in the current driving state is first gear;

When χ>0.5, it is determined that the appropriate gear for the vehicle in the current driving state is second gear.

The beneficial effects of the present invention are:

The adaptive cruise shift control method based on the dual-stage planetary two-speed transmission provided by the present invention can determine the gear suitable for the current vehicle driving according to the road vehicle conditions and the driving environment, thereby assisting the driver to determine the correct shifting timing, so that The vehicle remains in efficient working order.

Description of drawings

Figure 1 is a schematic structural diagram of a two-speed planetary transmission based on the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement it with reference to the text of the description.

The invention provides an adaptive cruise shift control method based on a dual-stage planetary two-speed transmission. When the vehicle is driving, it determines the gear suitable for the current vehicle according to the road vehicle conditions and the driving environment to ensure that the vehicle is in an efficient working state.

As shown in Figure 1, the two-speed transmission based on the two-stage planetary row of the present invention is driven by an electric drive system, in which the transmission is composed of a first planetary row, a second planetary row and a clutch; the electric drive system includes: a first planetary row motor and a second motor.

The first motor is composed of a motor shaft 110, a stator 120, and a rotor 130. The stator 120 of the first motor is fixedly connected to the housing 100, and the rotor 130 of the first motor is fixedly connected to the first motor shaft 110. The second motor 410 is The gear is meshed with the ring gear 340 of the second planetary row, and an electromagnetic fixed lock is added to the output shaft of the second motor 410 to simulate the effect of the brake. The output shaft 150 passes through the through hole of the drive system housing to the outside of the housing. When driving, the first motor is in the motor mode, and the electromagnetic fixed lock on the output shaft of the second motor 410 acts to brake the ring gear 340 of the second planetary row; when braking, the first motor and the second motor are in the power generation mode. machine mode. The first planet row is a set of double planet rows, which consists of the first planet row planet carrier 210, the first planet row inner ring gear 250, the first planet row sun gear 220, the first planet row first planet gear 230 and the first planet row. The planet row is composed of the second planet wheel 240. The second planet row is a set of single planet row, which is composed of the second planet row sun gear 320, the second planet row planet gear 330, the second planet row planet carrier 310 and the second planet row inner ring gear 340. The second motor 410 is fixed on the housing 100. The second motor 410 is connected through a gear meshing with the outer ring gear on the second planetary row inner ring gear 340 to realize the rotation and braking of the second planetary row inner ring gear 340. . The clutch hub of clutch 420 (normally open) is connected to the second planetary gear carrier 310, and the clutch plate of clutch 420 (normally open) is installed on the intermediate shaft 140, and the second planetary gear carrier 310 is realized through the separation and combination of clutch 420 (normally open). The separation and combination of the planetary gear carrier 310 and the intermediate shaft 140 .

The gear switching of the electric drive system is realized by the electromagnetic fixed lock and the clutch 420 (normally open) on the output shaft of the second motor 410.

In the first gear, the first motor rotates forward (the motor rotation direction to realize the forward movement of the vehicle is the forward direction), the clutch 420 does not work and remains in the normally open state, and the electromagnetic fixed lock on the output shaft of the second motor 410 works to prevent the vehicle from moving forward. action. In the second gear, the first motor rotates forward, the clutch 420 works, that is, it is coupled, and the electromagnetic fixed lock on the output shaft of the second motor 410 does not work, and does not function as a brake. In the process of upgrading from first gear to second gear, the clutch 420 is switched to the working state through the shift control unit, and the electromagnetic fixed lock on the output shaft of the second motor 410 is switched to the inoperative state. In the process of downgrading from second gear to first gear, the clutch 420 is switched to the inactive state through the shift control unit, and the electromagnetic fixed lock on the output shaft of the second motor 410 is switched to the working state. In reverse gear, the first motor rotates reversely, and the clutch 420 does not work and remains in the normally open state. The electromagnetic fixed lock on the output shaft of the second motor 410 works to exert a braking effect. In neutral gear, the clutch 420 and the output shaft of the second motor 410 The electromagnetic locks on the motor remain inactive, so that the first motor shaft 110 and the output shaft 150 are in a separated state, cutting off power transmission. When the vehicle is traveling in first gear and needs to be braked, the first motor switches from motor mode to generator mode, braking the transmission system and converting the vehicle's driving kinetic energy into electrical energy. When the vehicle is traveling in second gear and needs to brake, the first motor and the second motor switch from motor mode to generator mode, the clutch 420 (normally open) works, and the second motor 410 becomes a generator, which plays a role in the transmission system. Drag function.

The adaptive cruise shift control method based on a dual-stage planetary two-speed transmission includes the following steps:

Step 1. Obtain the vehicle's speed, accelerator opening, vehicle mass, the vehicle in front, and the distance between the vehicle and the vehicle in front through sensors. The controller receives the above signals and performs the control according to the vehicle's speed, accelerator opening, and The vehicle's mass, the speed of the vehicle ahead and the distance between the vehicle and the vehicle ahead determine the vehicle's base gear coefficient;

Wherein, the reference gear coefficient of the vehicle is:

Among them, ξ is the correction parameter; α is the throttle opening, α ₀ is the benchmark throttle opening; m is the vehicle mass, in Kg; m ₀ is the benchmark vehicle mass, in Kg; v is the vehicle speed, in Km/ h; v ₀ is the speed of the vehicle in front, in Km/h; S is the distance between the vehicle in front and the vehicle in front, in m; S ₀ is the reference distance between the vehicle in front and the vehicle in front, in m; e is the natural pair The base of the number.

In another embodiment, the value of the correction parameter ξ is: when v≤50Km/h, ξ=0.6; when v>50Km/h, ξ=1. Determine the values of other parameters as: S ₀ =10m, m ₀ =2000Kg, α ₀ =50%.

Step 2: Obtain the outdoor ambient temperature, humidity, road adhesion coefficient and outdoor light intensity. The controller receives the above signals and determines the environmental coefficient for vehicle driving based on the outdoor ambient temperature, humidity, road adhesion coefficient and outdoor light intensity.

The environmental coefficient of the vehicle driving is:

Among them, a and b are correction parameters; μ is the road adhesion coefficient, RH is the relative humidity of the environment; RH ₀ is the relative humidity of the reference environment; T is the ambient temperature, in °C; T ₀ is the reference ambient temperature, in °C; I is outdoor Light intensity, unit Lux; I ₀ is the reference outdoor light intensity, unit Lux; e is the base of natural logarithm.

In another embodiment, the values of the correction parameters a and b are determined according to the temperature and humidity respectively: when RH<50%, a=0.6; when RH≥50%, a=0.7; and when T≤0 ℃, b = 0.6; when T > 0 ℃, b = 0.4. Determine the values of other parameters: T ₀ =20°C, RH ₀ =50%, I ₀ =300Lux.

Step 3: Determine the appropriate gear of the vehicle in the current driving state based on the vehicle's reference gear index and the vehicle's driving environment index. The specific method is: determining the current gear coefficient according to the reference gear coefficient of the vehicle and the environmental coefficient of the vehicle driving:

χ=χ ₀ ·E;

Among them, when χ ≤ 0.5, it is judged that the appropriate gear of the vehicle in the current driving state is first gear;

When χ>0.5, it is determined that the appropriate gear for the vehicle in the current driving state is second gear.

In another embodiment, the adhesion coefficient μ of the road surface is obtained based on big data recognition. The specific process is:

(1) Establish a road image database, and store the information obtained after image processing and the corresponding road adhesion coefficient as comparison information in the background of the information processing module.

(2) The vehicle-mounted camera captures road information in real time and transmits it to the information processing module for image preprocessing.

The SAID dual-domain image denoising algorithm is used here to remove irrelevant features such as impurities and noise in the image.

(3) Extract key features of the image. Here, the LBP operator that can describe texture is used for feature extraction. The formula of this operator is as follows:

P is the number of pixels on the circle, R is the radius of the circle, n _c is the pixel value of the neighborhood center, s(x) is the pixel value of the pixels on the circle, LBP _{P, R} is the LBP code.

Divide the preprocessed image into 4×4 non-overlapping areas, and calculate the LBP histogram of each area separately. Then each histogram is cascaded in the order of row first and then column. The cascaded feature is the LBP histogram of the entire image.

(4) Calculate the similarity between the LBP histogram of the background image and the real-time road surface image. The specific formula is as follows:

In the formula, g _i is the histogram of the background image, s _i is the histogram of the real-time road image, N is the number of histogram samples, and Q is the image similarity value. After comparing the similarity of all background images, the background image with the largest Q value is taken as the final road surface for recognition, and the corresponding road adhesion coefficient is read, which is the road adhesion coefficient μ of the car running at this time.

The gear position control method provided by the present invention can be used to control the gear position during automatic driving; an early warning device can also be set up in the cab, and the gear shifting information is transmitted to the early warning device through the controller to control the driver during manual driving. Gear shifting tips.

Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and embodiments. They can be applied to various fields suitable for the present invention. For those familiar with the art, they can easily Additional modifications may be made, and the invention is therefore not limited to the specific details and illustrations shown and described herein without departing from the general concept defined by the claims and equivalent scope.

Claims (4)

1. An adaptive cruise shift control method based on a dual-stage planetary two-speed transmission, which is characterized by including the following steps: Step 1: Obtain the speed of the own vehicle, the accelerator opening, the mass of the own vehicle, the speed of the preceding vehicle and the distance between the own vehicle and the preceding vehicle, and based on the speed of the own vehicle, the accelerator opening, the mass of the own vehicle, the speed of the preceding vehicle and The distance between the vehicle in front and the vehicle in front determines the vehicle’s base gear coefficient; Step 2: Obtain the outdoor ambient temperature, humidity, road adhesion coefficient and outdoor light intensity, and determine the environmental coefficient for vehicle driving based on the outdoor ambient temperature, humidity, road adhesion coefficient and outdoor light intensity; Step 3: Determine the appropriate gear of the vehicle in the current driving state based on the vehicle's baseline gear index and the vehicle's driving environment index; The base gear coefficient of the vehicle is: Among them, ξ is the correction parameter; α is the throttle opening, α ₀ is the benchmark throttle opening; m is the vehicle mass, m ₀ is the benchmark vehicle mass; v is the speed of the own vehicle, v ₀ is the speed of the preceding vehicle; S is The distance between the vehicle in front and the vehicle in front, S ₀ is the reference distance between the vehicle in front and the vehicle in front; e is the base of the natural logarithm; The environmental coefficient of the vehicle driving is: Among them, a and b are correction parameters; μ is the road adhesion coefficient, RH is the relative humidity of the environment; RH ₀ is the relative humidity of the reference environment; T is the ambient temperature, T ₀ is the reference ambient temperature; I is the outdoor light intensity, and I ₀ is Baseline outdoor light intensity; e is the base of the natural logarithm. 2. The adaptive cruise shift control method based on a dual-stage planetary two-speed transmission according to claim 1, characterized in that the value of the correction parameter ξ is: When v≤50Km/h, ξ=0.6; When v>50Km/h, ξ=1. 3. The adaptive cruise shift control method based on the dual-stage planetary two-speed transmission according to claim 1 or 2, characterized in that the values of the correction parameters a and b are respectively: When RH<50%, a=0.6; When RH≥50%, a=0.7; and When T≤0℃, b=0.6; When T>0℃, b=0.4. 4. The adaptive cruise shift control method based on the dual-stage planetary two-speed transmission according to claim 3, characterized in that in the step three, according to the reference gear coefficient of the vehicle and the vehicle The driving environment coefficient determines the current gear coefficient as: χ=χ ₀ ·E; Among them, when χ ≤ 0.5, it is judged that the appropriate gear of the vehicle in the current driving state is first gear; When χ>0.5, it is determined that the appropriate gear for the vehicle in the current driving state is second gear.