CN110043651B - Slope road driving gear shifting control method based on two-stage planetary gear transmission - Google Patents

Abstract

The invention discloses a slope road driving gear shifting control method based on a two-stage planetary gear transmission, which comprises the following steps: step one, when a vehicle runs, acquiring the running speed, the accelerator opening, the whole vehicle mass and the road surface gradient of the vehicle, and determining a reference gear coefficient of the vehicle according to the running speed, the accelerator opening, the whole vehicle mass and the road surface gradient of the vehicle; step two, acquiring outdoor environment temperature, humidity and road surface adhesion coefficient, and determining the running environment coefficient of the vehicle according to the outdoor environment temperature, humidity and road surface adhesion coefficient; 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 vehicle running. The slope road driving gear shifting control method based on the two-stage planetary gear transmission can determine the proper gear suitable for the vehicle according to the road surface gradient and the driving environment, ensure that the vehicle is in a high-efficiency working state and reduce the driving energy consumption of the vehicle.

Description

A shifting control method for hill driving 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 a shift control method for hill driving 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 on a slope, the driver needs to change the gear according to the actual situation to keep the vehicle in efficient working condition. However, in the actual driving process, some drivers are unable to accurately judge the timing of shifting due to lack of experience, resulting in low vehicle efficiency and poor performance. High consumption.

Contents of the invention

The invention provides a shift control method for hill driving based on a dual-stage planetary two-speed transmission. The purpose is to determine the appropriate gear position for the vehicle according to the road slope and the driving environment, so as to ensure that the vehicle is in an efficient working state and reduce the vehicle speed. Driving energy consumption.

The technical solution provided by the invention is:

A shift control method for hill driving based on a dual-stage planetary two-speed transmission, including:

Step 1: While the vehicle is driving, obtain the vehicle's driving speed, accelerator opening, vehicle mass and road surface gradient, and determine the vehicle's base gear coefficient based on the vehicle's driving speed, accelerator opening, vehicle mass and road surface gradient;

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

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 vehicle speed, v ₀ is the benchmark vehicle speed; i is the road slope, |i| represents the absolute value of the road slope; 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 base environment; T is the ambient temperature, T ₀ is the base ambient temperature; 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:

I=I ₀ ·E;

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

When I>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 invention provides a shift control method for hill driving based on a dual-stage planetary two-speed transmission, which can determine the appropriate gear position for the vehicle according to the road slope and the driving environment, ensure that the vehicle is in an efficient working state, and reduce the energy consumption of the vehicle.

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 a shift control method for driving on a slope based on a dual-stage planetary two-speed transmission. When driving on a slope, the appropriate gear position for the vehicle is determined according to the road gradient 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 device, wherein the transmission is composed of a first planetary row, a second planetary row and a clutch; the electric drive device includes a first motor and a second motor.

The first motor is composed of a first motor shaft 110, a stator 120 and a rotor 130. Among them, the stator 120 of the first motor is fixedly connected to the casing 100, the rotor 130 of the first motor is fixedly connected to the first motor shaft 110, the second motor 360 is a reversible motor, and the second motor 360 is connected to the inner teeth of the second planetary row. The external gear of the ring 350 is connected, and the external gear and the second planetary row internal ring gear 350 are of an integrated structure. The first motor shaft 110 is rotatably connected to the housing 110 and connected to the first planetary sun gear 220; the output shaft 140 extends to the outside of the housing. The first planet row sun gear 220 is installed at the end of the first motor shaft 110 , and the first planet row planet gear 230 meshing with the first planet row sun gear 220 is installed at the left end of the first planet row planet gear shaft 240 . The planet gear shaft 240 is mounted on the first planet row carrier 210 through a bearing, and the first planet row internal ring gear 250 meshing with the first planet row planet gear 230 is connected to the first planet row sun gear 220 through the clutch 410. The planetary gear carrier 210 is connected to the housing 100 through a brake 420 . The second planet row sun gear 320 is fixedly mounted on the second planet row sun gear shaft 330 , and the second planet row planet gear 340 is mounted on the second planet row planet carrier 310 through bearings. The second planet row planet carrier 310 is connected to The output shaft 140 is connected, and the second planetary row internal ring gear 350 is fixedly connected to the housing 100 . The clutch hub of clutch 410 (normally open) is connected to the first planetary row inner ring gear 250, and the clutch plate of clutch 410 (normally open) is connected to the first motor shaft 110, and is realized by the separation and combination of clutch 410 (normally open). The separation and coupling of the first planetary row inner ring gear 250 and the first motor shaft 110 . The brake hub of the brake 420 is connected to the housing 100 and is fixed. The brake disc of the brake 420 is connected to the first planetary gear carrier 210, and the separation and combination of the brake 420 realizes the rotation of the first planetary gear carrier 210. Turning and braking.

Gear switching is realized by clutch 410 (normally open) and brake 420. Specifically, in the first gear, the first motor rotates forward, the clutch 410 does not work, the first planetary gear ring gear 250 is separated from the first motor shaft 110, the brake 420 works, and plays a braking role. The star rack 310 transmits power to the output shaft 140 to realize power transmission. In the second gear, the first motor rotates forward, the clutch 410 operates, and the power is transmitted to the output shaft 140 through the second planetary gear carrier 310 to realize power transmission. In the process of upgrading from first gear to second gear, the clutch 410 is switched to the working state through the shift control unit; the brake 420 is switched to the inoperative state, and the first planetary gear carrier 210 is switched from being fixedly connected to the housing 100 to being connected to the housing 100 Separate and rotatable. In the process of downgrading from second gear to first gear, the clutch 410 is switched to the inactive state and the brake 420 is switched to the working state through the shift control unit. In reverse gear, the first motor rotates reversely, the clutch 410 does not work, the first planetary gear ring gear 250 is separated from the first motor shaft 110, the brake 420 works, and plays a braking role. Through the second planetary gear carrier 310 The power is transmitted to the output shaft 140 to realize the output of power and make the whole vehicle travel in reverse direction. In neutral gear, both the clutch 410 and the brake 420 remain inactive, so that the first motor shaft 110 and the output shaft 140 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 and the second motor switch 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 be braked, the first motor and the second motor switch from the motor mode to the generator mode, the clutch 410 does not work, and the brake 420 works, which plays a dragging role in the transmission system.

The invention provides a shift control method for hill driving based on a dual-stage planetary two-speed transmission, including the following steps:

Step 1. When the vehicle is driving, the vehicle's driving speed, accelerator opening, vehicle mass and road surface gradient are obtained through the sensor. The controller receives the above-mentioned signals and controls the vehicle according to the vehicle's driving speed, accelerator opening, vehicle mass and road surface gradient. 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, Km/h ; v ₀ is the reference vehicle speed, Km/h; i is the road gradient, |i| represents the absolute value of the road gradient; e is the base of the natural logarithm.

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

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

Among them, 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 base environment; T is the ambient temperature, in °C; T ₀ is the base ambient temperature, in °C; e is the natural The base of logarithms.

In another embodiment, the values of the correction parameters a and b are respectively determined according to the temperature and humidity: 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 as follows: T ₀ =20°C, RH ₀ =50%.

Step 3: The controller determines 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 judgment method is as follows:

The current gear coefficient is determined based on the vehicle's reference gear coefficient and the vehicle's driving environment coefficient as:

I=I ₀ ·E;

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

When I>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 neighborhood center pixel value, 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 similarity comparison 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 controller transmits the gear shifting information to the early warning device, which is used to change the driver's gear during manual driving. block prompt.

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. A shift control method for hill driving based on a dual-stage planetary two-speed transmission, which is characterized by including the following steps: Step 1: While the vehicle is driving, obtain the vehicle's driving speed, accelerator opening, vehicle mass and road surface gradient, and determine the vehicle's base gear coefficient based on the vehicle's driving speed, accelerator opening, vehicle mass and road surface gradient; Step 2: Obtain the outdoor ambient temperature, humidity and road adhesion coefficient, and determine the environmental coefficient for vehicle driving based on the outdoor ambient temperature, humidity and road adhesion coefficient; 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 vehicle speed, v ₀ is the benchmark vehicle speed; i is the road slope, |i| represents the absolute value of the road slope; 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 base environment; T is the ambient temperature, T ₀ is the base ambient temperature; e is the base of the natural logarithm. 2. The shift control method for hill driving 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 shift control method for hill driving 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 shift control method for hill driving based on a 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: I=I ₀ ·E; Among them, when I ≤ 0.5, it is judged that the appropriate gear of the vehicle in the current driving state is first gear; When I>0.5, it is determined that the appropriate gear for the vehicle in the current driving state is second gear.