CN113700847B - AMT (automated mechanical transmission) -matched commercial vehicle low-speed control method, device and equipment - Google Patents
AMT (automated mechanical transmission) -matched commercial vehicle low-speed control method, device and equipment Download PDFInfo
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- CN113700847B CN113700847B CN202111013810.7A CN202111013810A CN113700847B CN 113700847 B CN113700847 B CN 113700847B CN 202111013810 A CN202111013810 A CN 202111013810A CN 113700847 B CN113700847 B CN 113700847B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/02—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
- F16H61/0202—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric
- F16H61/0204—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric for gearshift control, e.g. control functions for performing shifting or generation of shift signal
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/04—Smoothing ratio shift
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Abstract
The application discloses commercial vehicle low-speed control method, device and equipment matched with AMT, comprising the following steps: determining whether the vehicle is in a low-speed coupling control section; calculating a desired net engine output torque and an available engine friction torque; determining whether to enable a drive actuator and determining whether the vehicle is in a drive state based on the desired net engine output torque and available engine friction torque; if the driving actuator is determined to be enabled, when the vehicle is in a low-speed coupling control interval and the vehicle is in a driving state, calculating low-speed compensation torque, and obtaining engine request torque according to the low-speed compensation torque, engine friction torque and expected engine net output torque; when the vehicle is not in the low-speed coupling control interval and the vehicle is in a driving state, the engine request torque is the sum of the expected engine net output torque and the engine friction torque, good control on low-speed running of the matching AMT vehicle is achieved, starting and stopping are reduced, and riding comfort is improved.
Description
Technical Field
The application relates to the technical field of automatic driving, in particular to a method and a device for controlling low speed of a commercial vehicle matched with an AMT (automated mechanical transmission) and computer equipment.
Background
Current full speed adaptive cruise ACCs are either developed based on pure electric vehicles or developed with passenger cars that are matched to AT transmissions. The pure electric vehicle type generally has no gearbox, and the motor control linearity is good, and is relatively easy in low-speed control. And the passenger car matched with AT has flexible connection of a hydraulic torque converter, and the power transmission can be kept continuous AT low speed. For a commercial vehicle matched with the AMT, due to a rigid mechanical connection structure with limited gears, under the condition that the vehicle speed is low, the transmission case controls the clutch to be in a semi-engagement state in order to ensure that the rotating speed of the engine is not lower than the idle rotating speed, meanwhile, the control unit of the AMT limits the torque of the engine, coupling is generated between the control unit and a traditional vehicle speed control method, and the torque limiting instruction priority of the AMT control unit is higher, so that great control difficulty is brought.
Disclosure of Invention
The application mainly aims to provide a low-speed control method, a low-speed control device and computer equipment for AMT (automated mechanical transmission) commercial vehicles, and aims to solve the technical problems that due to a rigid mechanical connection structure with limited gears, an AMT control unit can limit the torque of an engine under the condition that the vehicle speed is low, great difficulty is brought to control of low-speed running of the vehicles, and the vehicles are easy to start and stop frequently.
In a first aspect, the present application provides a method for controlling a low speed of a commercial vehicle matched with an AMT, the method comprising the following steps:
determining whether the vehicle is in a low-speed coupling control interval;
calculating a desired net engine output torque and an available engine friction torque;
determining whether to enable a drive actuator and determining whether the vehicle is in a drive state based on the desired net engine output torque and the available engine friction torque;
if the driving actuator is enabled, when the vehicle is in a low-speed coupling control interval and the vehicle is in a driving state, calculating low-speed compensation torque, and obtaining engine request torque according to the low-speed compensation torque, engine friction torque and the expected engine net output torque; when the vehicle is not in a low-speed coupling control range and the vehicle is in a driving state, the engine request torque is the sum of the desired engine net output torque and an engine friction torque;
the vehicle drive control is activated in accordance with the motive force requested torque.
In some embodiments, the determining whether the vehicle is in the low speed coupling section includes:
when the torque limit of a gearbox of the vehicle is requested to an engine, the gearbox does not send a gear shifting instruction and the current gear is a forward gear;
or when the current gear of the gearbox is a forward gear and the vehicle speed is lower than the idle driving vehicle speed.
In some embodiments, the calculating the desired net engine output torque comprises:
calculating an expected vehicle speed and an expected acceleration according to the vehicle speed, the relative vehicle speed of the front vehicle and the relative distance between the vehicle and the front vehicle;
according to the formula:
a cmp ＝k p (v tar -v curr )+∑k i (v tar -v curr ) Calculating a compensation acceleration;
wherein, a cmp To compensate for acceleration, k p For proportional control parameters, k i For integrating the control parameter, v tar To the desired vehicle speed, v curr The actual vehicle speed;
according to the formula:
wherein, T req_net To the desired net engine output torque, a tar To expect acceleration, a cmp To compensate for acceleration, F f To rolling resistance, F i As slope resistance, F r M is the total mass of the vehicle, delta is the rotating mass conversion coefficient, eta is the transmission efficiency of the power system, i g For the current gear ratio of the gearbox, i 0 Is the vehicle final drive gear ratio.
In some embodiments, the calculating available engine friction torque comprises:
according to the formula:
T fric_available ＝max(0,min(T fric ,(T fric -Tc urr ) ) calculating the available engine friction torque;
wherein, T fric_available For available engine friction torque, T fric For engine friction torque, T curr Is the current output torque of the engine;
when the current output torque of the engine is equal to 0, judging that the friction torque of the engine is completely available;
when the current output torque of the engine is larger than 0 and smaller than the friction torque of the engine, judging that the friction torque part of the engine is available;
and when the current output torque of the engine is larger than or equal to the friction torque of the engine, judging that the friction torque of the engine is unavailable.
In some embodiments, said determining whether to enable driving an actuator and determining whether the vehicle is in a drive state based on said desired net engine output torque and said available engine friction torque comprises:
when the sum of the expected engine net output torque and the available engine friction torque is smaller than a set lower torque interval limit, determining that the vehicle is in a braking state, and enabling the brake actuator;
when the sum of the expected engine net output torque and the available engine friction torque is larger than the set upper torque interval limit, determining that the vehicle is in a driving state, and enabling the driving actuator;
when the sum of the expected net engine output torque and the available engine friction torque is within the set torque interval, maintaining the brake actuator or the drive actuator enabled in the previous cycle.
In some embodiments, if it is determined that the driving actuator is enabled, calculating a low-speed compensation torque when the vehicle is in a low-speed coupling control section and the vehicle is in a driving state includes:
calculating a difference value between the sum of the expected engine net output torque and the engine friction torque and the current output torque of the engine, setting a compensation coefficient according to the difference value, wherein the compensation coefficient is in direct proportion to the difference value, and according to a formula:
wherein, T cmp For low speed torque compensation, factor is the compensation factor, T req_net For desired net engine output torque, T fric As engine friction torque, T curr Is the current output torque of the engine.
In some embodiments, said deriving an engine requested torque based on said low speed compensation torque, an engine friction torque, and said desired engine net output torque comprises according to the formula:
T req ＝T req_net +T fric +T cmp calculating the engine requested torque;
wherein, T req Requesting torque for the engine, T req_net For desired net engine output torque, T fric For engine friction torque, T cmp The torque is compensated for at low speed.
In some embodiments, if it is determined that the drive actuator is not enabled, a brake actuator is enabled and a braking control of the vehicle is activated based on a sum of the desired acceleration and the compensated acceleration.
In a second aspect, the present application further provides a commercial vehicle low-speed control device matched with the AMT, the device includes:
the interval determining module is used for determining whether the vehicle is in a low-speed coupling control interval;
a data calculation module for calculating a desired net engine output torque and an available engine friction torque;
an actuator determination module to determine whether to enable actuation of an actuator and to determine whether the vehicle is in a drive state based on the desired net engine output torque and the available engine friction torque;
a torque acquisition module for calculating a low-speed compensation torque when the vehicle is in a low-speed coupling control zone and the vehicle is in a driving state, and obtaining an engine request torque according to the low-speed compensation torque, an engine friction torque and the desired engine net output torque when it is determined that the driving actuator is enabled; when the vehicle is not in a low-speed coupling control range and the vehicle is in a driving state, the engine request torque is the sum of the desired engine net output torque and an engine friction torque;
a control module to activate the vehicle drive control based on the motive request torque.
In a third aspect, the present application further provides a computer device, which includes a processor, a memory, and a computer program stored on the memory and executable by the processor, wherein when the computer program is executed by the processor, the steps of the AMT-matched commercial vehicle low-speed control method are implemented.
The application provides a commercial vehicle low-speed control method and device matched with an AMT, computer equipment and a computer readable storage medium, wherein whether an actuator is enabled or not is determined according to a calculated expected engine net output torque and a calculated available engine friction torque; activating vehicle drive control if it is determined that the drive actuator is enabled; and if the driving actuator is determined not to be enabled, activating vehicle brake control, realizing good control on low-speed running of the matched AMT gearbox vehicle, reducing frequent starting and stopping, and improving riding comfort.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic flow chart of a method for controlling a commercial vehicle at a low speed by matching with an AMT according to an embodiment of the present disclosure;
FIG. 2 is a detailed flowchart of a commercial vehicle low-speed control method matched with an AMT;
FIG. 3 is a schematic block diagram of a AMT-matched commercial vehicle low-speed control device provided by the embodiment of the application;
fig. 4 is a schematic block diagram of a structure of a computer device according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. 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 application.
The flowcharts shown in the figures are illustrative only and do not necessarily include all of the contents and operations/steps, nor do they necessarily have to be performed in the order described. For example, some operations/steps may be decomposed, combined or partially combined, so that the actual execution order may be changed according to the actual situation.
The embodiment of the application provides a commercial vehicle low-speed control method and device matched with an AMT (automated mechanical transmission), and computer equipment. The method can be applied to computer equipment, and the computer equipment can be electronic equipment such as a notebook computer and a desktop computer.
Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments and features of the embodiments described below can be combined with each other without conflict.
Referring to fig. 1, fig. 1 is a schematic flow chart of a method for controlling a commercial vehicle at a low speed matching with an AMT according to an embodiment of the present disclosure.
As shown in fig. 1, the method includes steps S1 to S5.
The method comprises the following steps of S1, determining whether a vehicle is in a low-speed coupling control interval or not;
step S2, calculating the net output torque of the expected engine and available engine friction torque;
step S3, determining whether to enable a driving actuator and determining whether the vehicle is in a driving state according to the expected engine net output torque and the available engine friction torque;
step S4, if the driving actuator is enabled, when the vehicle is in a low-speed coupling control interval and the vehicle is in a driving state, calculating low-speed compensation torque, and obtaining engine request torque according to the low-speed compensation torque, engine friction torque and the expected engine net output torque; when the vehicle is not in a low-speed coupling control zone and the vehicle is in a driving state, the engine requested torque is the sum of the desired engine net output torque and an engine friction torque;
and S5, activating the vehicle driving control according to the motive power request torque.
Referring to fig. 2, fig. 2 is a specific flowchart of a method for controlling a low speed of a commercial vehicle matched with an AMT.
As a preferred embodiment, the specific method for matching the AMT for the low speed control of the commercial vehicle is to calculate the net output torque of the expected engine and the available engine friction torque, and determine the currently enabled actuator; when the enabled actuator is a driving actuator, judging whether the vehicle is in a low-speed coupling control interval, if so, calculating low-speed compensation torque, calculating final engine request torque according to the low-speed compensation torque, the engine friction torque and the expected engine net output torque, otherwise, directly obtaining the final engine request torque without calculating the low-speed compensation torque, and activating driving control according to the engine request torque; when the enabled actuator is not a driving actuator, the brake control is directly activated to achieve control of the vehicle. The specific steps of the method will be described in detail below.
It is worth mentioning that, for a vehicle matched with the AMT automatic gearbox, due to the rigid mechanical connection structure of the limited gear, under the condition of low vehicle speed, the gearbox controls the clutch to be in a semi-engaged state in order to ensure that the engine speed is not lower than the idle speed, and meanwhile, the control unit of the AMT limits the engine torque, and generates coupling with the traditional vehicle speed control method, and the torque limit command priority of the AMT control unit is higher. In the normal gear shifting process, the AMT gearbox controller also controls the torque of the engine because the rotating speed of the output shaft of the engine needs to be controlled to be synchronous with the rotating speed of the input shaft of the gearbox, so that the difference between a low-speed coupling control interval and a gear shifting state needs to be discriminated, and the method for identifying whether the vehicle is in the low-speed coupling interval comprises the following steps:
when satisfied, the transmission requests a torque limit for the engine; the gearbox does not send a gear shifting command; the current gear of the gearbox is a forward gear, and the vehicle can be judged to be in a low-speed coupling interval under the three conditions. Or the current gear of the gearbox is a forward gear; the vehicle speed is lower than the idling driving speed, and the vehicle can be judged to be in a low-speed coupling interval under the two conditions.
As a preferred embodiment, since the idle driving speed is related to the vehicle configuration parameters and the current driving gear, the lower limit of the idle driving speed is calculated by the following formula:
wherein v is idle The lower limit of the idling speed of the current gear, n idle For engine idle speed, R is the rolling radius of the vehicle tire, i g For the current gear ratio of the gearbox, i 0 Is the vehicle final drive gear ratio.
Exemplary, a method of calculating a desired net engine output torque includes: the method comprises the steps of firstly collecting information such as the speed of a vehicle, the relative speed of the vehicle and a front vehicle and the relative distance between the vehicle and the front vehicle to obtain a desired speed and a desired acceleration, then calculating a compensation acceleration according to the speed of the vehicle and the desired speed, and then calculating a desired net engine output torque according to the compensation acceleration and the desired acceleration. Since the desired vehicle speed and the desired acceleration are calculated by the conventional calculation method, they will not be described in detail.
Further, when calculating the compensated acceleration, the compensated acceleration is calculated using a PI controller based on a deviation value between the vehicle speed of the host vehicle and the desired vehicle speed, and the calculation formula of the compensated acceleration is as follows:
a cmp ＝k p (v tar -v curr )+∑k i (v tar -v curr )
wherein, a cmp To compensate for acceleration, k p For proportional control parameters, k i For integrating the control parameter, v tar To the desired vehicle speed, v curr Is the actual vehicle speed.
It is worth mentioning that, because the power transmission system of the vehicle is actually in an unstable state in the low-coupling control region, the torque transmission characteristic of the clutch becomes nonlinear with the slip film, and in order to increase the stability of the vehicle speed control, the present invention uses the integral term Σ k of the PI controller when the vehicle enters the low-coupling control region i (v tar -v curr ) Freezing, then initializing to a default value according to a set change slope, and only keeping the calculation of the proportional term. The default value of the integral term of the present invention is set to 0.
As a preferred embodiment, the net output torque of the desired engine is calculated from the compensated acceleration and the desired acceleration by the following formula:
wherein, T req_net To the desired net engine output torque, a tar To expect acceleration, a cmp To compensate for acceleration, F f To rolling resistance, F i As slope resistance, F r M is the total mass of the vehicle, delta is the rotating mass conversion coefficient, eta is the transmission efficiency of the power system, i g For the current gear ratio of the gearbox, i 0 Is the vehicle final drive gear ratio.
For example, the engine friction torque may be used for braking deceleration, and in order to fully utilize the engine friction torque for deceleration, it is set that the brake actuator is enabled to perform braking deceleration when the expected net engine output torque is smaller than the available engine friction torque, otherwise, only the accelerator is released for deceleration. Under the normal driving condition, because the speed of a vehicle is higher, in the braking state, the rotating speed of the engine cannot be lower than the idling rotating speed only by dragging the vehicle transmission system, the engine can not actively spray oil, and at the moment, all the engine friction torque can be fully utilized to decelerate. However, when the vehicle enters the low-speed coupling control interval from the normal driving working condition, because the vehicle speed is low, in order to ensure that the rotating speed of the engine is not lower than the idle rotating speed, the engine can actively inject oil to enter the idle speed control mode, at the moment, the friction torque of the engine is not fully available, and the friction torque of the engine is not fully available until the clutch is completely separated. In order to accurately calculate the available engine friction torque in the process and ensure that the friction torque is continuously changed when entering a low-speed coupling control interval from a normal running condition, the invention provides the following formula and a method for determining the available friction torque, wherein the calculation formula is as follows:
T fric_available ＝max(0,min(T fric ,(T fric -T curr )))
wherein, T fric_available For available engine friction torque, T fric As engine friction torque, T curr Is the current output torque of the engine. T is a unit of fric_available Available engine friction torque CAN be obtained through a CAN bus, and the value of the available engine friction torque is greater than or equal to 0; t is curr The current output torque of the engine CAN be acquired through a CAN bus, and the value of the current output torque is more than or equal to 0; when the current output torque T of the engine curr Equal to 0, indicating that the engine friction torque is fully available, when the current output torque T of the engine curr Greater than 0 and less than engine friction torque T fric This indicates that the engine friction torque is partially available when the engine currently outputs torque T curr Greater than or equal to engine friction torque T fric At this time, the engine friction torque is not available when the engine output torque completely overcomes the friction torque. Specifically, reference to engine friction torque as used herein refers to the use of engine friction torque to slow a vehicle down.
Further, the method can be used for preparing a novel materialDue to the above-mentioned current output torque T of the engine curr The actual output torque of the engine fed back in response to the control instruction of the previous cycle is controlled to eliminate the influence of the algebraic loop and to make the available friction torque change earlier so as to avoid the available friction torque changing to the engine friction torque T fric The invention adds the upper and lower limits of torque judgment when the actuator enables judgment, and can determine the state of the vehicle and the actuator needing to be enabled according to the expected net output torque of the engine and the available friction torque of the engine after determining the available friction torque of the engine, and the specific method is as follows:
when net engine output torque T is desired req_net Friction torque T with available engine fric_available When the sum is less than the lower limit of the set torque judgment interval, judging that the vehicle is in a braking state, and enabling a brake actuator;
when net engine output torque T is desired req_net Friction torque T with available engine fric_available When the sum is larger than the upper limit of the set torque judgment interval, judging that the vehicle is in a driving state, and enabling to drive an actuator;
when net engine output torque T is desired re q _net Friction torque T with available engine fric_available And when the sum is between the upper limit and the lower limit of the torque judgment interval, judging the actuator which is kept enabled in the previous period.
The method is used for determining the vehicle state and the actuator which needs to be enabled, so that the friction torque of the engine can be fully utilized, and the condition that the vehicle has a buffer zone in the driving and braking switching process and does not vibrate is ensured.
As a preferred embodiment, if it is determined that the enabled actuator is a driving actuator, and the vehicle is in a low-speed coupling control section and is also in a driving state, calculating a low-speed compensation torque, and when the vehicle enters the low-speed coupling control section and the vehicle is determined to be in the driving state, the AMT controller limits the engine torque, so that in order to enable the net output torque of the engine to reach a desired value, the invention provides a low-speed compensation torque calculation method, calculating a difference value between the sum of the desired net output torque of the engine and the engine friction torque and the current output torque of the engine, and setting a compensation coefficient according to the calculated difference value, wherein the compensation coefficient is proportional to the difference value by the following specific formula:
wherein, T cmp For low speed torque compensation, factor is the compensation factor, T req_net For desired net engine output torque, T fric For engine friction torque, T curr Is the current output torque of the engine. The coefficient is compared with the (T) currently calculated req_net +T fric -T curr ) In proportion, the larger the difference is, the larger the compensation coefficient can be set, and the smaller the difference is, the smaller the compensation coefficient can be set. The factor range set by the invention is between 0.8 and 1.2.
And then calculating to obtain engine request torque according to the calculated low-speed compensation torque and the expected engine net output torque, and when the vehicle state is in a low-speed coupling interval and the judged vehicle is in a driving state, sending the engine request torque to the engine as follows:
T req ＝T req_net +T fric +T cmp
wherein, T req Requesting torque for the engine, T req_net For desired net engine output torque, T fric For engine friction torque, T cmp The torque is compensated for at low speed.
It is to be noted that, after the engine request torque is obtained, the engine request torque activates the vehicle drive control, and the control of the vehicle is realized.
In a preferred embodiment, when the vehicle is not in the low-speed coupling section and the determined vehicle state is in the driving state, the engine request torque to the engine is:
T req ＝T req_net +T fric
wherein, T req Requesting torque for the engine, T req_net For desired net engine output torque, T fric Is the engine friction torque.
As a preferred embodiment, if it is determined that the actuator is not enabled, i.e. the vehicle is determined to enable the brake actuator, the sum of the desired acceleration and the compensated acceleration value may be directly issued to the electronically controlled brake system, and the vehicle brake control may be activated to control the deceleration of the vehicle. The electronically controlled brake system herein may directly respond to a deceleration control request.
By the method, ultra-low speed control can be realized on commercial vehicles matched with AMT, and the minimum speed can reach 1kph. Under the congested working condition, the vehicle can keep going forward at a low speed, reduce frequent starting and parking and improve the riding comfort.
Referring to fig. 3, fig. 3 is a schematic block diagram of a commercial vehicle low-speed control device matched with an AMT according to an embodiment of the present application.
As shown in fig. 3, the apparatus includes: the device comprises an interval determining module, a data calculating module, an actuator determining module, a torque obtaining module and a control module.
An interval determination module for determining whether the vehicle is in a low-speed coupling interval;
a data calculation module for calculating a desired net engine output torque and an available engine friction torque;
an actuator determination module to determine whether to enable actuation of an actuator and to determine whether the vehicle is in a drive state based on the desired net engine output torque and the available engine friction torque;
a torque acquisition module for calculating a low-speed compensation torque when the vehicle is in a low-speed coupling control zone and the vehicle is in a driving state, and obtaining an engine request torque according to the low-speed compensation torque, an engine friction torque and the desired engine net output torque when it is determined that the driving actuator is enabled; when the vehicle is not in a low-speed coupling control zone and the vehicle is in a driving state, the engine requested torque is the sum of the desired engine net output torque and an engine friction torque;
a control module to activate the vehicle drive control based on the motive requested torque.
It is worth mentioning that the control module is used for determining whether the vehicle is in the low-speed coupling section, and the specific identification method is as follows:
when satisfied, the transmission requests a torque limit for the engine; the gearbox does not send a gear shifting command; the current gear of the gearbox is a forward gear, and the vehicle can be judged to be in a low-speed coupling interval under the three conditions. Or the current gear of the gearbox is a forward gear; the vehicle speed is lower than the idling driving speed, and the vehicle can be judged to be in a low-speed coupling interval under the two conditions.
As a preferred embodiment, since the idle driving speed is related to the vehicle configuration parameters and the current driving gear, the lower limit of the idle driving speed is calculated by:
wherein v is idle The lower limit of the idling speed of the current gear, n idle For engine idle speed, R is the rolling radius of the vehicle tire, i g For the current gear ratio of the gearbox, i 0 Is the vehicle final drive gear ratio.
Because for the vehicle matched with the AMT automatic gearbox, due to the rigid mechanical connection structure of the limited gear, under the condition of low vehicle speed, the gearbox is to ensure that the engine speed is not lower than the idle speed, the clutch is controlled to be in a semi-engaged state, and meanwhile, the control unit of the AMT limits the engine torque, so that coupling is generated between the control unit of the AMT and the traditional vehicle speed control method, and the priority of the torque limiting command of the AMT control unit is higher. In the normal gear shifting process, the AMT gearbox controller also controls the torque of the engine because the rotating speed of the output shaft of the engine needs to be controlled to be synchronous with the rotating speed of the input shaft of the gearbox, so that the difference between a low-speed coupling control interval and a gear shifting state needs to be discriminated.
It should be noted that the data calculation module is used for calculating the expected net engine output torque by first collecting information such as the vehicle speed of the host vehicle, the relative vehicle speed of the host vehicle to the front vehicle, and the relative distance between the host vehicle and the front vehicle to obtain an expected vehicle speed and an expected acceleration, then calculating a compensated acceleration according to the vehicle speed of the host vehicle and the expected vehicle speed, and then calculating the expected net engine output torque according to the compensated acceleration and the expected acceleration. Since the desired vehicle speed and the desired acceleration are calculated by the conventional calculation method, they will not be described in detail.
Further, when calculating the compensation acceleration, the compensation acceleration is calculated by using a PI controller based on a deviation value between the vehicle speed of the host vehicle and the desired vehicle speed, and the calculation method of the compensation acceleration is as follows:
a cmp ＝k p (v tar -v curr )+∑k i (v tar -v curr )
wherein, a cmp To compensate for acceleration, k p For proportional control parameters, k i For integrating the control parameter, v tar To the desired vehicle speed, v curr Is the actual vehicle speed.
It should be noted that, since the powertrain of the vehicle is actually in an unstable state in the low-coupling control region and the torque transmission characteristic of the clutch becomes nonlinear with the slip film, the present invention makes the integral term Σ k of the PI controller when the vehicle enters the low-coupling control region in order to increase the stability of the vehicle speed control i (v tar -v curr ) Freezing, then initializing to a default value according to a set change slope, and only keeping the calculation of the proportional term. The default value of the integral term of the present invention is set to 0.
As a preferred embodiment, the net output torque of the desired engine is calculated from the compensated acceleration and the desired acceleration by the equation:
wherein, T reg_net For a desired net engine output torque, a tar To expect acceleration, a cmp To compensate for acceleration, F f To rolling resistance, F i As slope resistance, F r M is the total vehicle mass, delta is the rotating mass conversion coefficient, eta is the powertrain transmission efficiency, i g For the current gear ratio of the gearbox, i 0 Is the vehicle final drive gear ratio.
Further, the data calculation module is used for calculating available engine friction torque, the engine friction torque can be used for braking and decelerating, in order to fully utilize the engine friction torque for decelerating, the brake actuator is set to be enabled to brake and decelerate when the expected net output torque of the engine is smaller than the available engine friction torque, otherwise, only the accelerator is released for decelerating. Under the normal driving condition, because the speed of a vehicle is higher, when in a braking state, the rotating speed of the engine cannot be lower than the idling rotating speed only by dragging the vehicle transmission system, the engine cannot actively spray oil, and at the moment, all engine friction torques can be fully utilized for speed reduction. However, when the vehicle enters the low-speed coupling control interval from the normal driving working condition, because the vehicle speed is low, in order to ensure that the rotating speed of the engine is not lower than the idle rotating speed, the engine can actively inject oil to enter the idle speed control mode, at the moment, the friction torque of the engine is not fully available, and the friction torque of the engine is not fully available until the clutch is completely separated. In order to accurately calculate the available engine friction torque in the process and ensure that the friction torque is continuously changed when entering a low-speed coupling control interval from a normal running condition, the invention provides the following formula and a method for determining the available friction torque, wherein the calculation formula is as follows:
T fric_available ＝max(0,min(T fric ,(T fric -T curr )))
wherein, T fric_available For available engine friction torque, T fric For engine friction torque, T curr Is the current output torque of the engine. T is a unit of fric_available Available engine friction torque CAN be obtained through a CAN bus, and the value of the available engine friction torque is greater than or equal to 0; t is curr The current output torque of the engine CAN be acquired through a CAN bus, and the value of the current output torque is more than or equal to 0;when the current output torque T of the engine curr Equal to 0, indicating that the engine friction torque is fully available, when the current output torque T of the engine curr Greater than 0 and less than engine friction torque T fric This means that the engine friction torque is partially available when the current output torque T of the engine is curr Greater than or equal to engine friction torque T fric At this time, the engine friction torque is unavailable when the engine output torque completely overcomes the friction torque. Specifically, reference to engine friction torque as used herein refers to the use of engine friction torque to slow down a towing vehicle.
Further, the present output torque T of the engine due to the above curr The actual output torque of the engine fed back in response to the control instruction of the previous cycle is controlled to eliminate the influence of the algebraic loop and to make the available friction torque change earlier so as to avoid the available friction torque changing to the engine friction torque T fric The method comprises the following steps that when the available friction torque of an engine is determined, the state of a vehicle and an actuator needing to be enabled can be determined according to the expected net output torque of the engine and the available friction torque of the engine, and a specific method for determining whether the enabled actuator is a driving actuator by an actuator determining device is as follows:
when net engine output torque T is desired req_net Friction torque T with available engine fric_available When the sum is less than the lower limit of the set torque judgment interval, judging that the vehicle is in a braking state, and enabling a brake actuator;
when net engine output torque T is desired req_net Friction torque T with available engine fri c _available When the sum is larger than the upper limit of the set torque judgment interval, judging that the vehicle is in a driving state, and enabling to drive an actuator;
when net engine output torque T is desired req_net Friction torque T with available engine fric_available And when the sum is between the upper limit and the lower limit of the torque judgment interval, judging the actuator which is kept enabled in the previous period.
The method is used for determining the vehicle state and the actuator which needs to be enabled, so that the friction torque of the engine can be fully utilized, and the condition that the vehicle has a buffer zone in the driving and braking switching process and does not vibrate is ensured.
In a preferred embodiment, the actuator determining device is configured to determine that the enabled actuator is a driving actuator, and when the vehicle is in a low-speed coupling control interval and is also in a driving state, calculate a low-speed compensation torque, and when the vehicle enters the low-speed coupling control interval and the vehicle is determined to be in the driving state, the AMT controller limits the engine torque, so that, in order to enable the net output torque of the engine to reach a desired value, the invention provides a low-speed compensation torque calculating method, which calculates a difference between a sum of the desired net output torque of the engine and the engine friction torque and a current output torque of the engine, and sets a compensation coefficient according to the calculated difference, wherein the compensation coefficient is proportional to the difference by a specific formula as follows:
wherein, T cmp For low speed torque compensation, factor is the compensation factor, T req_net For desired net engine output torque, T fric For engine friction torque, T curr Is the current output torque of the engine. The coefficient being related to the current calculation
In proportion, the larger the difference is, the larger the compensation coefficient can be set, and the smaller the difference is, the smaller the compensation coefficient can be set. The factor range set by the invention is between 0.8 and 1.2.
Further, the torque obtaining module is used for obtaining an engine request torque through calculation according to the calculated low-speed compensation torque and the expected engine net output torque, and when the vehicle state is in the low-speed coupling interval and the judged vehicle is in the driving state, the engine request torque sent to the engine is as follows:
T req ＝T req_net +T fric +T cmp
wherein, T req Requesting torque for the engine, T req_net For desired net engine output torque, T fric As engine friction torque, T cmp The torque is compensated for at low speed.
It is worth mentioning that the control module is used for activating the vehicle driving control by the engine request torque after obtaining the engine request torque, so as to realize the control of the vehicle.
In a preferred embodiment, when the vehicle is not in the low-speed coupling range and the determined vehicle state is not in the driving state, the engine request torque to the engine is:
T req ＝T req_net +T fric
wherein, T req Requesting torque for the engine, T req_net For desired net engine output torque, T fric Is the engine friction torque.
In a preferred embodiment, when the actuator determining module determines that the actuator is not enabled, that is, when the vehicle is determined to enable the brake actuator, the sum of the expected acceleration and the compensated acceleration value can be directly sent to the electronically controlled brake system, so as to activate the vehicle brake control and control the deceleration of the vehicle. The electronically controlled brake system here can directly respond to the deceleration control request.
By the method, ultra-low speed control can be realized on the commercial vehicle matched with the AMT, and the minimum speed can reach 1kph. Under the working condition of congestion, the vehicle can keep moving forward at a low speed, reduces frequent starting and stopping, and improves the riding comfort.
It should be noted that, as will be clear to those skilled in the art, for convenience and brevity of description, the specific working processes of the apparatus and the modules and units described above may refer to the corresponding processes in the foregoing embodiments, and are not described herein again.
The apparatus provided by the above embodiments may be implemented in the form of a computer program, which can be run on a computer device as shown in fig. 4.
Referring to fig. 4, fig. 4 is a schematic block diagram of a structure of a computer device according to an embodiment of the present disclosure. The computer device may be a terminal.
As shown in fig. 4, the computer device includes a processor, a memory and a network interface connected by a system bus, wherein the memory may include a nonvolatile storage medium and an internal memory.
The non-volatile storage medium may store an operating system and a computer program. The computer program comprises program instructions that, when executed, cause a processor to perform any of the methods.
The processor is used for providing calculation and control capability and supporting the operation of the whole computer equipment.
The internal memory provides an environment for the execution of a computer program on a non-volatile storage medium, which when executed by a processor causes the processor to perform any of the methods.
The network interface is used for network communication, such as sending assigned tasks and the like. Those skilled in the art will appreciate that the architecture shown in fig. 4 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.
It should be understood that the Processor may be a Central Processing Unit (CPU), and the Processor may be other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. Wherein a general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of other like elements in a process, method, article, or system comprising the element.
The above-mentioned serial numbers of the embodiments of the present application are merely for description, and do not represent the advantages and disadvantages of the embodiments. While the invention has been described with reference to specific embodiments, the scope of the invention is not limited thereto, and those skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the invention. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (9)
1. A commercial vehicle low-speed control method matched with an AMT is characterized by comprising the following steps:
determining whether the vehicle is in a low-speed coupling control section;
calculating a desired net engine output torque and an available engine friction torque;
determining whether to enable a drive actuator and determining whether the vehicle is in a drive state based on the desired net engine output torque and the available engine friction torque;
if the driving actuator is enabled, when the vehicle is in a low-speed coupling control interval and the vehicle is in a driving state, calculating low-speed compensation torque, and obtaining engine request torque according to the low-speed compensation torque, engine friction torque and the expected engine net output torque; when the vehicle is not in a low-speed coupling control zone and the vehicle is in a driving state, the engine requested torque is the sum of the desired engine net output torque and an engine friction torque;
activating the vehicle drive control in accordance with the engine requested torque;
wherein said calculating available engine friction torque comprises:
according to the formula:
T fric_available ＝max(0，min(T fric ，(T fric -T curr ) ) calculating the available engine friction torque;
wherein, T fric_available Available engine friction torque, T fric As engine friction torque, T curr Is the current output torque of the engine;
when the current output torque of the engine is equal to 0, judging that the friction torque of the engine is completely available;
when the current output torque of the engine is larger than 0 and smaller than the friction torque of the engine, judging that the friction torque part of the engine is available;
and when the current output torque of the engine is larger than or equal to the friction torque of the engine, judging that the friction torque of the engine is unavailable.
2. The matching AMT commercial vehicle low-speed control method according to claim 1, wherein said determining whether the vehicle is in the low-speed coupling control section comprises:
when the torque limit of a gearbox of the vehicle is requested to an engine, the gearbox does not send a gear shifting instruction and the current gear is a forward gear;
or when the current gear of the gearbox is a forward gear and the vehicle speed is lower than the idle driving vehicle speed.
3. The AMT-matched commercial vehicle low-speed control method according to claim 1, wherein said calculating a desired engine net output torque comprises:
calculating an expected speed and an expected acceleration according to the vehicle speed, the relative speed of the front vehicle and the relative distance between the vehicle and the front vehicle;
according to the formula:
a cmp ＝k p (v tar -v curr )+∑k i (v tar -v curr ) Calculating a compensation acceleration;
wherein, a cmp To compensate for acceleration, k p As a proportional control parameter, k i For integral control parameters, v tar To the desired vehicle speed, v curr The actual vehicle speed;
according to the formula:
wherein, T req_net For a desired net engine output torque, a tar To expect acceleration, a cmp To compensate for acceleration, F f As rolling resistance, F i As slope resistance, F r M is the total mass of the vehicle, delta is the rotating mass conversion coefficient, eta is the transmission efficiency of the power system, i g For the current gear ratio of the gearbox, i 0 Is the vehicle final drive gear ratio.
4. The AMT-matched commercial vehicle low-speed control method according to claim 1, wherein said determining whether to enable driving of the actuator and determining whether the vehicle is in a driving state based on said desired net engine output torque and said available engine friction torque comprises:
when the sum of the expected engine net output torque and the available engine friction torque is smaller than the set lower torque interval limit, determining that the vehicle is in a braking state, and enabling a brake actuator;
when the sum of the expected engine net output torque and the available engine friction torque is larger than the set upper torque interval limit, determining that the vehicle is in a driving state, and enabling the driving actuator;
when the sum of the desired net engine output torque and the available engine friction torque is within the set torque interval, then maintaining the brake actuator or the drive actuator enabled in the previous cycle.
5. The AMT-matched commercial vehicle low-speed control method according to claim 1, wherein said calculating a low-speed compensation torque when said vehicle is in a low-speed coupling control section and said vehicle is in a driving state if it is determined that said driving actuator is enabled, comprises:
calculating a difference between the sum of the expected net engine output torque and the engine friction torque and the current engine output torque, setting a compensation factor according to the difference, wherein the compensation factor is proportional to the difference, and according to a formula:
T cmp ＝factor*(T reqnet +T fric -T curr ) Calculating the low-speed compensation torque;
wherein, T cmp For low speed torque compensation, factor is the compensation factor, T req_net For desired net engine output torque, T fric As engine friction torque, T curr Is the current output torque of the engine.
6. The matched AMT commercial vehicle low-speed control method according to claim 5, wherein said obtaining an engine request torque based on said low-speed compensation torque, engine friction torque and said desired engine net output torque comprises according to the formula:
T req ＝T req_net +T fric +T cmp calculating the engine requested torque;
wherein, T req Requesting torque for the engine, T req_net For desired net engine output torque, T fric For engine friction torque, T cmp The torque is compensated for at low speed.
7. The AMT-matched commercial vehicle underspeed control method according to claim 1, wherein if it is determined that the driving actuator is not enabled, a braking actuator is enabled, and braking control of the vehicle is activated according to a sum of a desired acceleration and a compensated acceleration.
8. The utility model provides a match AMT's commercial car low-speed control device which characterized in that includes:
the interval determining module is used for determining whether the vehicle is in a low-speed coupling control interval;
a data calculation module for calculating a desired net engine output torque and an available engine friction torque;
an actuator determination module to determine whether to enable actuation of an actuator and to determine whether the vehicle is in a drive state based on the desired net engine output torque and the available engine friction torque;
a torque acquisition module for calculating a low-speed compensation torque when the vehicle is in a low-speed coupling control zone and the vehicle is in a driving state, and obtaining an engine request torque according to the low-speed compensation torque, an engine friction torque and the desired engine net output torque when it is determined that the driving actuator is enabled; when the vehicle is not in a low-speed coupling control zone and the vehicle is in a driving state, the engine requested torque is the sum of the desired engine net output torque and an engine friction torque;
a control module to activate the vehicle drive control in accordance with the engine requested torque;
wherein the data computation module is further configured to:
according to the formula:
T fricavailable ＝max(0，min(T fric ，(T fric -T curr ) ) calculating the available engine friction torque;
wherein, T fricavailable Available engine friction torque, T fric As engine friction torque, T curr Is the current output torque of the engine;
when the current output torque of the engine is equal to 0, judging that the friction torque of the engine is completely available;
when the current output torque of the engine is larger than 0 and smaller than the friction torque of the engine, judging that the friction torque part of the engine is available;
and when the current output torque of the engine is larger than or equal to the friction torque of the engine, judging that the friction torque of the engine is unavailable.
9. Computer arrangement, characterized in that the computer arrangement comprises a processor, a memory, and a computer program stored on the memory and executable by the processor, wherein the computer program, when executed by the processor, carries out the steps of the AMT matched commercial vehicle underspeed control method of any one of claims 1 to 7.
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