CN114435406A

CN114435406A - Vehicle control method and device and storage equipment

Info

Publication number: CN114435406A
Application number: CN202210291910.4A
Authority: CN
Inventors: 蔡渤
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-03-23
Filing date: 2022-03-23
Publication date: 2022-05-06

Abstract

The application provides a vehicle control method, a vehicle control device and a storage medium, which can realize automatic control of a vehicle. The method comprises the following steps: receiving A Driver Assistance System (ADAS) request corresponding to a target vehicle; acquiring a vehicle body signal corresponding to the target vehicle; determining the current state of the target vehicle according to the vehicle body signal corresponding to the target vehicle; determining a control instruction corresponding to the target vehicle according to the ADAS request and the current state of the target vehicle; and controlling the target vehicle according to the control instruction corresponding to the target vehicle.

Description

Vehicle control method and device and storage equipment

[ technical field ] A method for producing a semiconductor device

The application belongs to the field of automatic driving, and particularly relates to a vehicle control method and device and a storage device.

[ background of the invention ]

In recent years, Advanced Driver Assistance Systems (ADAS) have attracted more and more attention, and how to ensure that the ADAS controls the vehicle to be smooth involves Longitudinal dynamic Control (LoDC).

Different ADAS have different requirements on LoDC, for example, an Adaptive Cruise Control (ACC) only needs to Control vehicle acceleration and deceleration, an Automatic Parking Assist (APA) only needs to Control a gear and an Electronic Parking system (EPB), and an Automatic Emergency braking system (AEB) needs to perform Emergency braking, so that different ADAS have different LoDC Control architectures and software at present.

[ summary of the invention ]

The application provides a control method of a vehicle and related equipment, which can realize automatic control of the vehicle.

A first aspect of the present application provides a control method of a vehicle, including:

receiving A Driver Assistance System (ADAS) request corresponding to a target vehicle;

acquiring a vehicle body signal corresponding to the target vehicle;

determining the current state of the target vehicle according to the vehicle body signal corresponding to the target vehicle;

determining a control instruction corresponding to the target vehicle according to the ADAS request and the current state of the target vehicle;

and controlling the target vehicle according to the control instruction corresponding to the target vehicle.

A second aspect of the present application provides a vehicle control apparatus including:

a receiving unit, configured to receive a driver assistance system ADAS request corresponding to a target vehicle;

the acquisition unit is used for acquiring a vehicle body signal corresponding to the target vehicle;

the first determining unit is used for determining the current state of the target vehicle according to the vehicle body signal corresponding to the target vehicle;

a second determining unit, configured to determine, according to the ADAS request and the current state of the target vehicle, a control instruction corresponding to the target vehicle;

and the control unit is used for controlling the target vehicle according to the control instruction corresponding to the target vehicle.

A third aspect of the present application provides a computer device comprising: at least one connected processor, memory, and transceiver; wherein the memory is configured to store program codes, and the processor is configured to call the program codes in the memory to execute the steps of the control method of the vehicle according to the first aspect.

A fourth aspect of embodiments of the present application provides a computer storage medium comprising instructions that, when executed on a computer, cause the computer to perform the steps of the control method of the vehicle according to any one of the above aspects.

Compared with the related art, in the embodiments provided by the present application, after receiving the ADAS request and the body CAN signal, the vehicle control device may determine the current state of the vehicle according to the body CAN signal, determine the control instruction of the vehicle according to the ADAS request and the current state of the vehicle, and control the vehicle according to the control instruction of the vehicle, so as to implement automatic control of the vehicle.

[ description of the drawings ]

Fig. 1 is a system architecture diagram of a vehicle control device provided in an embodiment of the present application;

fig. 2 is a functional architecture diagram of a LoDC controller provided in an embodiment of the present application;

FIG. 3 is a schematic flow chart illustrating a control method for a vehicle according to an embodiment of the present disclosure;

fig. 4 is a schematic view illustrating a vehicle stress analysis corresponding to a target vehicle according to an embodiment of the present application;

FIG. 5 is a schematic view of a virtual structure of a vehicle control device according to an embodiment of the present application;

fig. 6 is a schematic hardware structure diagram of a server according to an embodiment of the present application.

[ detailed description ] embodiments

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 only a part of the embodiments of the present application, and not all of the embodiments.

Referring to fig. 1, fig. 1 is an architecture diagram of a vehicle control system according to an embodiment of the present application, wherein an LoDC controller 103 receives an ADAS request 101 and a vehicle body CAN signal 102 of a vehicle, wherein the ADAS request includes, but is not limited to, an acceleration/deceleration request, a start request, a stop request, an EPB request, a gear request, and an emergency brake request, and the vehicle body CAN signal includes, but is not limited to, a vehicle speed, a wheel pulse, a wheel direction, an acceleration/deceleration, a steering wheel angle, a gear, and a torque; after receiving the ADAS request and the body CAN signal, the LoDC controller 103 may determine a current state of the vehicle according to the body CAN signal, and determine a Control command of the vehicle according to the ADAS request and the current state of the vehicle, where the Control command may be a driving torque, a braking torque, an EPB command, and a gear command, and then the LoDC controller 103 sends the driving torque to an Engine Management System (EMS) 104, sends the braking torque to an Electronic stability System (ESP) 105, sends an Electronic Parking Brake (EPB) command to an EPB106, and sends the gear command to a Transmission Control Unit (TCU) 107, so as to implement automatic Control of the vehicle.

Referring to fig. 2, fig. 2 is a functional architecture diagram of a LoDC controller according to an embodiment of the present application, wherein,

the LoDC controller mainly includes a LoDC state machine 201, an Input filtering module 202, a slope estimation module 203, a slope monitoring module 204, a fault detection module 205, a failure detection module 206, an Override module 207, a Drive Off module 208, a Driving Ctrl module 209, a Stop module 210, an emergency braking module 211, and an arbitration module 212, which are described in detail below:

the LoDC state machine 201 is mainly used to determine which state is in, so as to manage and coordinate the operation of each software module, that is, the request that the LoDC needs to execute currently, such as an acceleration request, a deceleration request, a start request or a brake request, and different states of the vehicle correspond to different ADAS requests.

The input of the LoDC state machine 201 is: the ADAS acceleration and deceleration AccelReq, ADAS start command driveffreq, ADAS stop command StopReq, ADAS emergency brake command EmergencyReq, vehicle speed spd _ ms, failure detection result LoDC _ Error, slope sliding flag, obstacle encountering flag ObsFlag, and driver override flag, and the output of the LoDC state machine 201 is described below with reference to table 1, where table 1 is an output table of the LoDC state machine:

TABLE 1

The LoDC state machine 201 is described in detail below:

default entry into standby is initialized, and LoDC _ state is 1 standby.

When LoDC _ Error is equal to 0, entering an Error state, and LoDC _ state is equal to 7 Error; when LoDC _ Error is 0, the standby state is returned.

When ADAS _ AccelReq is 1, the vehicle is indicated to enter an Active state, and LoDC _ ContrSt and LoDC _ Active _ tosec are set to be 1; meanwhile, the default vehicle firstly enters a driveoff state, and LoDC _ state is 2 driveOffCtrl; when the vehicle speed spd is larger than 2km/h, the vehicle is started, the vehicle enters a driving state, and the LoDC _ state is 3driving Ctrl; when ADAS _ StopReq is 1, the vehicle is requested to stop, and the LoDC _ state is 4 StopCtrl; when ADAS _ EmgReq is 1, it indicates that Emergency braking is requested, the vehicle enters into the Emergency state, and LoDC _ state is 5 Emergency.

When the driver Override is monitored, the vehicle enters the Override state, LoDC _ state is 6Override, and LoDC _ conterst and LoDC _ Active _ tosec are set to 0.

The Input filtering module 202 mainly performs filtering processing on Input signals, and performs conversion, such as unit conversion, on the Input signals, namely the ADAS request and the car body CAN signal, and since some signals are in an unstable state, smooth filtering is required on the Input signals, and the physical units of some signals do not match the units required by operation, conversion is required.

It can be understood that the Input filtering module 202 mainly performs filtering processing on Input, using first-order low-pass filtering, and the formula is as follows:

y(n)＝k.x(n)+(1-k)*y(n-1)；

k represents the filter coefficient, x (n) represents the current input (i.e., all signals requiring filtering, including but not limited to braking torque on the wheels, left front wheel impulse, left and right wheel impulse, left rear wheel impulse, right rear wheel impulse, vehicle speed, left front wheel speed, right front wheel speed, left rear wheel speed, right rear wheel speed, left rear wheel direction, right rear wheel direction, left front wheel direction, right front wheel direction, yaw angle, and longitudinal acceleration), y (n-1) represents the output result at the previous time, and y (n) represents the filtered result at the current time.

The gradient estimation module 203 is mainly used for estimating the gradient of a road on which the vehicle runs, and a longitudinal acceleration sensor can be arranged on the vehicle, wherein the relation formula of the acceleration and the gradient is as follows:

ax＝g*θ+dv/dt；

where ax represents the measured actual acceleration, g represents the gravitational acceleration, θ represents the gradient, and dv/dt represents the vehicle speed derivative, and transforming this equation yields the gradient θ (ax-dv/dt)/g, and then filtering the gradient, i.e., outputting the gradient.

The hill-drop detection module 204 is mainly used for detecting whether the vehicle is rolling down a hill, and if the vehicle is detected to be rolling down a hill, the braking force needs to be increased, wherein the hill-drop detection module 204 outputs a hill-drop flag, 0 indicates that the vehicle is not rolling down a hill, and 1 indicates that the vehicle is rolling down a hill. When the vehicle is in the D gear but the vehicle is moving backward or when the vehicle is in the R gear but the vehicle is moving forward, it is said that the vehicle is sliding down a slope, so the gear and the vehicle driving direction may be determined.

The obstacle detection module 205 is mainly used for detecting whether the vehicle is stuck to an obstacle on the road surface, for example, the vehicle is stuck to a speed bump or a road edge, and if the vehicle is found to be stuck by the obstacle, the driving force needs to be increased. The obstacle detection 205 outputs a flag ObsFlag, 0 indicates normal, and 1 indicates that the obstacle vehicle is stuck. The obstacle detection 205 mainly detects that the vehicle is in a driving state, that is, when the vehicle is detected to be stopped, it indicates that the vehicle is stuck with an obstacle, and sets ObsFlag to 1.

The failure detection module 206 is mainly used to detect a system failure condition, and if the system failure is detected, the system exits and feeds back a related failure signal. The failure detection 206 mainly detects an Error condition of the related part, and when an ESC signal Error is monitored, LoDC _ Error is 1ESC Error; when an EMS signal Error is monitored, LoDC _ Error is 2EMS Error; when the TCU signal Error is monitored, LoDC _ Error is 3TCU Error; when an EPS signal Error is monitored, LoDC _ Error is 4EPS Error; when an EPB signal Error is detected, LoDC _ Error is 5EPB Error; when an ADAS signal Error is detected, LoDC _ Error ═ 6ADAS Error.

The Override detection module 207 detects the intervention of the driver, and if the intervention of the driver is detected, the system exits. The Override detection 207 outputs a flag Override, when judging that the driver steps on an accelerator, a brake or shifts gears, the driver is involved in operation, and in order to not interfere the driving of the driver, the system sets the Override to 1 and then controls to quit.

The DriveOff module 208 realizes control of DriveOff ctrl starting, is divided into initial starting and non-initial starting according to an EPB state, and is mainly used for coordinated control of driving and braking during vehicle starting so as to ensure that the vehicle does not slide down a slope while starting.

The DrivingCtrl module 209 is used for controlling DrivingCtrl running, is mainly used for controlling normal running of the vehicle after starting, and aims to respond to acceleration and deceleration of the upper layer of the ADAS and meet the acceleration and deceleration requirements of the ADAS.

The Stop module 210 implements Stop control, and is mainly used for coordinated control of driving and braking when the vehicle is stopped, so as to ensure that the vehicle does not slide down a slope when the vehicle is stopped, and meanwhile, the P gear and the EPB are engaged after the function is finished.

The Emergency braking module 211 implements Emergency braking, which is Emergency braking control of the vehicle under Emergency conditions.

The arbitration 212 mainly arbitrates according to the results calculated by the state machine 201 and each module, and then sends the results to each association part to realize the control of the vehicle. The arbitration 212 mainly determines whether the final output uses the DriveOffCtrl, drivevingctrl, StopCtrl, or EmergencyCtrl module according to the LoDC _ state output from the LoDC state machine 201. That is, the state machine judges whether the current action required to be executed is starting, accelerating, decelerating, emergency braking or braking action according to the ADAS acceleration and deceleration request signal and the action of treading the pedal by the driver; after receiving these states (which may also be understood as mode), the arbitration 212 determines whether to require engine reverse-tow deceleration (level road), or engine reverse-tow + brake parallel deceleration, or to reduce the speed (uphill) with engine torque 0, or to reduce the speed (uphill) with engine torque slightly reduced, or to start (level road or uphill) with engine output torque, or to start (downhill) with brake released, or to start (downhill) with brake slightly carried along.

It should be noted that the arbitration 212 may also perform clipping and slope limiting on the final output in order to prevent the calculated control amount from exceeding the range of the action capability of the hardware actuator and improve the safety.

The following describes a control method of a vehicle according to an embodiment of the present application from the perspective of a vehicle control device, which may be a LoDC controller.

Referring to fig. 3, fig. 3 is a schematic flow chart of a vehicle control method according to an embodiment of the present application, including:

301. and receiving A Driver Assistance System (ADAS) request corresponding to the target vehicle.

In this embodiment, the vehicle control device may receive an ADAS request corresponding to a target vehicle, where the ADAS request includes, but is not limited to, an acceleration/deceleration request, a start request, a stop request, an EPB request, a shift request, and an emergency braking request.

302. And acquiring a vehicle body signal corresponding to the target vehicle.

In this embodiment, the vehicle control device may obtain a vehicle body signal corresponding to the target vehicle, where the vehicle body signal includes, but is not limited to, a vehicle speed, a wheel pulse, a wheel direction, an acceleration and deceleration, a steering wheel angle, a gear, and a torque, and specifically, the vehicle control device may read the vehicle body signal through a sensor or a CAN corresponding to the vehicle.

303. And determining the current state of the target vehicle according to the vehicle body signal corresponding to the target vehicle.

In this embodiment, after acquiring the body signal corresponding to the target vehicle, the vehicle control device may determine the current state of the target vehicle according to the body model corresponding to the target vehicle, where the current state of the target vehicle includes a starting state (i.e., a DriveOff state in which the Lodc state machine shown in fig. 2 is located), a Driving state (i.e., a Driving state in which the Lodc state machine shown in fig. 2 is located), a parking control state (i.e., a StopCtrl state in which the Lodc state machine shown in fig. 2 is located), and an Emergency braking state (i.e., an Emergency state in which the Lodc state machine shown in fig. 2 is located).

It should be noted that the vehicle control device may acquire the ADAS request through step 301, and may determine the current state of the target vehicle through steps 302 to 303, however, there is no restriction on the execution sequence between step 301 and steps 302 to 303, and step 301 may be executed first, or step 302 to step 303 may be executed first, or executed at the same time, which is not limited specifically.

304. And determining a control instruction corresponding to the target vehicle according to the ADAS request and the current state of the target vehicle.

In this embodiment, after receiving the ADAS request and determining the current state of the target vehicle, the vehicle control device may determine the control command corresponding to the target vehicle according to the ADAS request and the current state of the target vehicle, specifically, may determine the driving torque corresponding to the target vehicle and determine the braking torque corresponding to the target vehicle according to the ADAS request, and finally determine the control command corresponding to the target vehicle according to the driving torque corresponding to the target vehicle and the braking torque corresponding to the target vehicle. The vehicle control device can determine the braking torque corresponding to the target vehicle through the following formula:

LoDC_BrkTrq_toESC＝max(100，20+abs(Ttq*n*i-m*g*slope*r))；

the method comprises the steps that LoDC _ BrkTrq _ tosEC is braking torque corresponding to a target vehicle, Ttq is engine torque of the target vehicle, n is transmission efficiency of the target vehicle, i is transmission ratio of the target vehicle, m is mass of the target vehicle, g is gravity acceleration, slope is angle of a slope where the target vehicle is located at present, and r is wheel radius of the target vehicle.

305. And controlling the target vehicle according to the control instruction corresponding to the target vehicle.

In this embodiment, after determining the control command corresponding to the target vehicle, the vehicle control device may control the target vehicle according to the control command, and how the vehicle control device controls the target vehicle according to the control command when the target vehicle is in different states is described below:

firstly, the current state of a target vehicle is a starting state:

when the current state of the target vehicle is a start state, the LoDC state machine defaults to an init state, the control amounts are all initialized to 0, LoDC _ BrkTrq _ tosec represents a braking torque requested to the ESC, LoDC _ BrkSt _ tosec represents a braking state requested to the ESC, LoDC _ TorqReq _ tosem represents a driving torque requested to the EMS, LoDC _ PressureReq _ tosec represents a pressure holding request requested to the ESC, and LoDC _ DriveOffReq _ tosec represents a start request requested to the ESC.

When LoDC _ state is 2DriveOffCtrl, start _1 stage is entered, and the brake pressure is first established. The brake pressure needs to be taken into account so that the vehicle does not roll down after the EPB is released.

The vehicle control device may first determine a drive torque corresponding to the target vehicle, and specifically may determine by the following equation:

the driving moment is equal to braking moment, ramp resistance, wind resistance, rolling resistance and acceleration resistance;

referring to fig. 4, fig. 4 is a schematic view illustrating a stress analysis of a target vehicle according to an embodiment of the present application, where when the target vehicle is on a slope and is in a starting state, a braking torque applied to the target vehicle is a sum of a slope resistance, a wind resistance, a rolling resistance, and an acceleration resistance, and therefore if it is to be ensured that the vehicle starts on the slope and does not slip on the slope, the driving torque that needs to be applied is greater than the braking torque.

In the vehicle starting stage, the wind resistance, the rolling resistance and the acceleration resistance are all 0, the driving torque is engine torque and acts on wheels, the engine torque Ttq CAN be directly read from a CAN corresponding to a target vehicle and acts on the wheels through a transmission system such as a hydraulic torque converter, and therefore the driving torque is required to be multiplied by a transmission ratio i and a transmission efficiency n, and the driving torque is Ttq n i;

the ramp resisting moment is the gravity component of the vehicle multiplied by the radius of the wheel, i.e. m g slope r, m is the mass of the vehicle, g is the gravity acceleration, slope is the ramp (the angle between the ramp and the horizontal plane), r is the radius of the wheel

The braking torque that needs to be applied is the drive torque minus the ramp drag torque: ttq × n × i-m × g × slope r;

meanwhile, in order to prevent the vehicle from sliding down a slope in a starting state, 20Nm (Newton-meter) is added on the basis of the calculated braking torque. In addition, in order to prevent the calculated braking torque from being excessively large, the maximum value is set to 100Nm, so the final braking torque formula is: LoDC _ BrkTrq _ tosec ═ max (100, 20+ abs (Ttq × n × i-m × g × slope × r)).

Therefore, the vehicle control device can adjust the actual driving torque corresponding to the target vehicle until the actual driving torque corresponding to the target vehicle reaches the braking torque when the target vehicle is in a starting state, and when the actual braking torque of the vehicle basically reaches the braking torque requested by LoDC and the EPB is not released, the vehicle control device enters a start _2 stage, releases the EPB and switches the gear to the electronic parking system EPB corresponding to the target vehicle.

It should be noted that ESC _ BrkTrq is the actual braking torque of the vehicle fed back by ESC, and in order to avoid the response deviation of the actuator, when the requested braking torque LoDC _ BrkTrq _ tosec-5 is reached, the brake is considered to have responded to the right; at this time, the release request to EPB is set, LoDC _ EPBReq _ tosec is 1, and the gear request is the gear request ADAS _ GearReq for ADAS forwarding.

After the EPB is released and the gear shift is completed, the start _3 stage is entered, the driving torque is increased, and the vehicle control device may increase the actual driving torque corresponding to the target vehicle according to a preset rule in consideration of comfort until the vehicle speed of the target vehicle is greater than 0, so as to implement the starting control of the target vehicle, for example, increase driving at a rate of 2 Nm. When the driving torque is increased enough to overcome the ramp resistance, the brake can be released, the start _4 stage is entered, and the driving torque is increased while the brake is released.

From the analysis in step 2, it is found that when the driving torque is Ttq × n × i > m × g × slope × r, the driving torque is greater than the hill resistance, and in order to avoid the calculation deviation, the calculated braking torque needs to be increased by 20Nm, and when the driving torque is greater than the hill resistance +20Nm, the driving torque is continuously increased, the brake is released, and the vehicle starts.

After the vehicle starts, the LoDC state may determine whether the vehicle starts, and if the vehicle starts successfully, the LoDC _ state may be set to 3 ═ DrivingCtrl, and the start control module enters the init state again to wait for the next start control. In addition, the brake torque obtained by the above calculation is increased by 20Nm and the maximum value 100Nm is set, which is merely an example, but may be set according to actual conditions, and is not limited specifically.

Secondly, the current state of the target vehicle is a running state:

when the target vehicle is in a running state, the ADAS request includes an acceleration request, a deceleration request and a braking request, and is controlled by an acceleration-braking coordination module, an acceleration torque control module and a braking torque control module, which are respectively described as follows:

1. an accelerated braking coordination module:

the accelerator brake coordination module is primarily responsible for coordinating the timing of acceleration and braking, i.e., when acceleration is performed and when braking is performed. The vehicle control device can analyze when the driver steps on the accelerator and the brake, and when the vehicle needs to accelerate, the driver can release the brake and step on the accelerator; when the vehicle needs small deceleration, a driver looses the accelerator first, the small deceleration is achieved through the resistances of wind resistance, rolling resistance, ramp resistance and the like, and the driver only needs to loosen the accelerator without stepping on the brake at the moment; when the vehicle needs large deceleration, the driver can step on the brake when the required deceleration can not be achieved through external resistance.

Therefore, the vehicle control device may determine whether or not the current target deceleration of the target vehicle is successfully matched with the deceleration requested by the deceleration request, the target deceleration being the deceleration of the target vehicle when the actual driving torque corresponding to the target vehicle is zero and the actual braking torque corresponding to the target vehicle is zero, the target deceleration being the deceleration that can be achieved when the driving torque and the braking torque are both 0, and if the target deceleration satisfies the deceleration requested by the ADAS, the braking torque does not need to be applied, but only the driving torque is controlled;

if the matching is unsuccessful, the actual braking torque corresponding to the target vehicle and the actual driving torque corresponding to the target vehicle are adjusted until the target deceleration is matched with the deceleration requested by the ADAS.

It should be noted that, in consideration of the calculation deviation, a transition zone is added in order to prevent the target vehicle from continuously shifting back and forth. The transition zone is that a buffer zone is added between two adjacent control quantity ranges, and the control quantity does not jump in the buffer zone so as to achieve the effects of gentle control and reduction of control impact. For example: when the vehicle speed reaches 30km/h, the gear 1 is hopped to the gear 2, but in order to prevent the gear from frequently hoping when the vehicle speed repeatedly fluctuates between 29.99 and 30.01, a buffer range with the width of 4km/h is added, namely, in the range of 28 to 32km/h, the gear 1 is kept without shifting gears, and the gear 2 is kept after the gear 2 is shifted.

2. An acceleration torque control module:

if the ADAS request is an acceleration request, the vehicle control device controls the target vehicle by a control method of a feed-forward torque + a feedback torque, wherein the feed-forward torque is calculated by the following formula:

the feedforward moment is braking moment + ramp resistance + wind resistance + rolling resistance + acceleration resistance;

the braking torque is 0 during acceleration, the ramp resistance is m g slope, m is the vehicle mass of the target vehicle, g is the gravity acceleration, slope is the ramp of the road where the target vehicle is located, the wind resistance formula is k v, k is the wind resistance coefficient, v is the vehicle speed, the rolling resistance is m g f, f is the rolling resistance coefficient, the acceleration resistance is m a, and a is the requested acceleration of the ADAS.

The feedback torque mainly uses a PID control method, wherein PID is: proportionality, Integral, and Differential, and the PID control algorithm is a control algorithm combining Proportional, Integral, and Differential.

In the application, the difference between the acceleration requested by the ADAS and the actual acceleration of the target vehicle is used as the input of the PID, wherein the proportion P control mainly carries out quick response to the error, the P coefficient is obtained by looking up the table according to the error size, and the integral I control carries out integral accumulation on the error and mainly eliminates the static error. It should be noted that the integral is considered to be anti-saturation, when the integral of the error is accumulated to exceed the maximum response of the executive component, if the integral is not anti-saturation, the integral is larger, when the control quantity needs to be reversely reduced, because the integral exceeds the maximum response and the time is required for reducing, a large time delay is caused, and the system is unstable. Meanwhile, when the error is larger than a certain value, the integral I control is not used, and the PD control is mainly used, because the I integral is mainly used for eliminating small static errors. The differential D control controls the rate of change of the error, and it is necessary to control the error change in advance in order to suppress overshoot of the control amount. However, the differential is sensitive to noise, so that a certain filtering process is required, and first-order low-pass filtering is adopted here.

It should be noted that, when the steering wheel is steered, the tire rotates to block the longitudinal force, and in order to compensate the resistance caused by steering, the table lookup is performed on the steering wheel angle to obtain the steering wheel compensation torque.

Thus, the vehicle control device can add the feedforward torque, the feedback torque, and the steering wheel compensation torque to obtain the acceleration drive torque when the ADAS request is the acceleration request, and can adjust the actual drive torque corresponding to the target vehicle until the acceleration drive torque is reached.

3. A braking torque control module:

if the ADAS request is a braking request, the vehicle control device controls the target vehicle by a control method of feedforward torque + feedback torque, wherein the feedforward torque is calculated by the following formula:

the feedforward moment is the driving moment- (ramp resistance + wind resistance + rolling resistance + acceleration resistance);

drive torque Ttq i n, where Ttq represents engine output torque, i represents drive ratio, and n represents transmission efficiency; the ramp resistance, wind resistance, rolling resistance, and acceleration resistance have been described in detail above and are not described in detail herein.

The feedback torque is mainly applied to a PID control method, and the difference between the deceleration requested by the ADAS and the actual deceleration of the vehicle is used as the input of the PID. And P control carries out table look-up according to the error, I control designs an anti-saturation strategy, and D control carries out filtering treatment.

Therefore, after the vehicle control device obtains the feedforward torque and the feedback torque, the sum of the feedforward torque and the feedback torque can be used as the braking control torque, the actual braking torque corresponding to the target vehicle is adjusted until the braking control torque is reached, and the braking control of the vehicle is realized.

Thirdly, the current state of the target vehicle is a parking control state:

if the target vehicle is in a parking control state, the LoDC state machine defaults to enter an init initialization stage, and the control output is 0; when the LoDC _ state is 4StopCtrl, entering a stage of stop _1, and reducing the actual driving torque corresponding to the target vehicle according to a preset reduction driving rule, that is, firstly, slowly releasing the throttle to reduce the driving torque, and preliminarily setting to reduce the driving torque at a rate of 30Nm (of course, the driving torque may also be set to other values); if the actual drive torque of the target vehicle is lower than a preset brake value (here, the preset brake value is 10Nm for example), increasing the brake torque according to a preset increase brake rule (for example, the brake torque may be increased at a rate of 10 Nm) until the target vehicle stops; in addition, the braking flag position LoDC _ BrkSt _ tosec, the parking flag position LoDC _ StopReq _ tosec, and the pressure maintaining flag position LoDC _ PressureReq _ tosec are all set to 1 while the braking torque is increased according to the preset braking rule.

When the vehicle stops, the vehicle control device enters a stop _2 stage, and needs to calculate a stopping braking torque for stopping the vehicle on a slope and adjust an actual braking torque corresponding to the target vehicle to the stopping braking torque in order to prevent the vehicle from rolling down the slope. If ADAS requests to pull EPB and put into P, then stage stop _3 is entered, requesting EPB to pull and put into P. When LoDC _ state is 4, the init phase is entered again.

It should be noted that the above-mentioned method for calculating the braking torque has been described in detail, and details are not repeated herein.

Fourthly, the current state of the target vehicle is an emergency braking state:

when the current state of the target vehicle is an Emergency braking state, Emergency braking processing mainly brakes with the maximum braking force and removes the driving torque. When the LoDC _ state is judged to be 5emergency, that is, 800Nm (calibratable) of braking torque is applied, while all of LoDC _ BrkTrqSt _ tossc, LoDC _ PressureReq _ tosec, LoDC _ StopReq _ tosec are set to 1, and the driving torque is set to 0. Namely, the actual driving torque corresponding to the target vehicle is adjusted to be zero, and meanwhile, the actual braking torque corresponding to the target vehicle is adjusted according to the preset emergency braking torque reduction rule until the vehicle speed of the target vehicle is zero.

It should be noted that, in the process of controlling the target vehicle, the vehicle control device may also determine in real time whether an operation instruction of the user is received, and if an operation instruction of the user is received, for example, an operation instruction of braking, shifting, refueling and the like of the user, control the target vehicle according to the operation instruction of the user. That is, the vehicle control device determines whether to return the control authority to the user by detecting the output flag bit Override by the Override, and when judging that the driver steps on the accelerator, steps on the brake or shifts gears, it indicates that the driver is in intervention operation, and in order not to interfere with the driving of the driver, the vehicle control device sets the Override to 1 and then controls to quit.

In one embodiment, after acquiring the body signal corresponding to the target vehicle, the vehicle control device further performs the following operations:

determining a road surface adhesion coefficient of a current running road surface of a target vehicle according to a vehicle body signal corresponding to the target vehicle;

and performing feedback optimization on the control command corresponding to the target vehicle according to the road adhesion coefficient.

In the present embodiment, the vehicle control device may determine the road adhesion coefficient of the road surface on which the target vehicle is currently traveling based on the road adhesion coefficient estimation of the μ -s curve when determining the road adhesion coefficient of the road surface on which the target vehicle is currently traveling from the vehicle body signal corresponding to the target vehicle. Specifically, the vehicle control device may first establish a vehicle dynamics model, wherein the dynamics model of the vehicle braking process may be described by the following formula:

wherein v is the longitudinal linear velocity of the wheel corresponding to the target vehicle, the unit is m/s, omega is the angular velocity of the wheel corresponding to the target vehicle, the unit is rad/s, m is the vehicle mass corresponding to the target vehicle, the unit is kg, R is the rotation radius of the wheel corresponding to the target vehicle, the unit is m, J is the rotation inertia of the wheel corresponding to the target vehicle, and the unit is kg.m²，T_bThe braking torque corresponding to the target vehicle is expressed in the unit of N.m, F_xThe longitudinal friction force is established for the tire corresponding to the ground and the target vehicle, mu is the adhesion coefficient between the tire and the ground, and g is the gravity acceleration.

The vehicle control apparatus may calculate the road adhesion coefficient μ using Magic formula:

the relationship between the longitudinal force of the tire and the longitudinal slip ratio s and the tire vertical load is expressed as:

wherein B is a stiffness coefficient, affecting the slope at s-0; c is a shape coefficient, which influences the shape of the whole curve; d is a peak coefficient, which influences the mu peak value; e is a curvature coefficient, which influences the local curvature change of the curve; a is₁～a₈Constants fitted from experimental data; the slip ratio s is defined as:

therefore, the relation between the longitudinal slip rate and the longitudinal adhesion coefficient of the tire under different road conditions can be determined. The above description describes how to calculate the road adhesion coefficient in one way, but it is needless to say that the road adhesion coefficient of the current road surface of the target vehicle may also be calculated in other ways, and the calculation is not limited specifically as long as the road adhesion coefficient of the current road surface of the target vehicle can be calculated.

After determining the road adhesion coefficient of the current running road surface of the target vehicle, the vehicle control device may determine an actual acceleration estimation value corresponding to the target vehicle according to the road adhesion coefficient, and perform feedback optimization on the control command corresponding to the target vehicle according to the actual acceleration estimation value corresponding to the target vehicle. The following is a detailed description of how to determine the actual acceleration estimation value corresponding to the target vehicle and how to perform feedback optimization of the control command:

based on the road adhesion coefficient, according to the vehicle dynamic model, and in combination with the actual test result of the target vehicle, it can be determined that under different road adhesion coefficients, the target vehicle has a nonlinear relationship between the expected actual acceleration due to tire slip during braking and acceleration and the acceleration under ideal road conditions, that is, the vehicle control device determines the actual acceleration estimation value corresponding to the target vehicle by the following formula:

the Accel _ Real is an actual acceleration estimated value corresponding to the target vehicle, the Accel _ Ideal is an acceleration corresponding to the target vehicle under an Ideal road surface condition, the K _ vehicle is a coefficient obtained by testing according to the weight, the tire specification and the gravity center position of the target vehicle, and the mu is an adhesion coefficient of a current running road surface of the target vehicle.

The vehicle control apparatus may feed back an actual acceleration estimated value corresponding to the target vehicle to the LoDC controller after determining the actual acceleration estimated value, and the LoDC controller may implement control of the target vehicle as an input to the PID based on the deceleration requested by the ADAS, the actual deceleration of the vehicle, and a difference between the expected acceleration of the vehicle and the actual acceleration estimated value. Therefore, the influence of the road adhesion coefficient on the maximum braking deceleration and the braking distance of the vehicle is considered, the braking and driving control can be optimized under the road surfaces with different adhesion coefficients, the danger of rear-end collision can be effectively reduced, and the driving experience in the driving process of the vehicle can be improved.

In summary, it CAN be seen that, in the embodiment provided by the present application, after receiving the ADAS request and the body CAN signal, the vehicle control device may determine the current state of the vehicle according to the body CAN signal, determine the control instruction of the vehicle according to the ADAS request and the current state of the vehicle, and control the vehicle according to the control instruction of the vehicle, so as to implement automatic control of the vehicle.

The present application is described above from the perspective of a vehicle control method, and the following description is from the perspective of a vehicle control device.

Referring to fig. 5, fig. 5 is a schematic virtual structure diagram of a vehicle control device according to an embodiment of the present application, where the vehicle control device 500 includes:

a receiving unit 501, configured to receive a driver assistance system ADAS request corresponding to a target vehicle;

an obtaining unit 502, configured to obtain a body signal corresponding to the target vehicle;

a first determining unit 503, configured to determine a current state of the target vehicle according to a body signal corresponding to the target vehicle;

a second determining unit 504, configured to determine, according to the ADAS request and the current state of the target vehicle, a control instruction corresponding to the target vehicle;

and a control unit 505, configured to control the target vehicle according to a control instruction corresponding to the target vehicle.

In one possible design, the second determining unit 504 is specifically configured to:

determining a driving torque corresponding to the target vehicle according to the ADAS request;

determining a braking torque corresponding to the target vehicle;

and determining a control command corresponding to the target vehicle according to the driving torque corresponding to the target vehicle and the braking torque corresponding to the target vehicle.

In one possible design, the second determining unit 504 determines the braking torque corresponding to the target vehicle by the following formula:

LoDC_BrkTrq_toESC＝max(100，20+abs(Ttq*n*i-m*g*slope*r))；

In one possible design, the control unit 505 is specifically configured to, if the current state of the target vehicle is a starting state, perform the following operations:

adjusting the actual driving torque corresponding to the target vehicle until the actual driving torque corresponding to the target vehicle reaches the braking torque when the target vehicle is in the starting state;

sending an electronic parking releasing instruction to an electronic parking system EPB corresponding to the target vehicle;

and increasing the actual driving torque corresponding to the target vehicle according to a preset rule until the speed of the target vehicle is greater than 0 so as to realize starting control of the target vehicle.

In a possible design, the control unit 505 is further specifically configured to, if the current state of the target vehicle is a driving state, perform the following operations:

if the ADAS request is a deceleration request, judging whether the current target deceleration of the target vehicle is successfully matched with the deceleration of the deceleration request, wherein the target deceleration is the deceleration of the target vehicle when the actual driving torque corresponding to the target vehicle is zero and the actual braking torque corresponding to the target vehicle is zero;

if the matching is unsuccessful, adjusting an actual braking torque corresponding to the target vehicle and an actual driving torque corresponding to the target vehicle until the target deceleration is matched with the deceleration requested by the ADAS;

if the ADAS request is an acceleration request, determining an acceleration feedback moment and a steering wheel compensation moment of the target vehicle;

determining an accelerated driving torque corresponding to the acceleration request according to the actual driving torque corresponding to the target vehicle, the feedback torque and the steering wheel torque;

adjusting an actual drive torque corresponding to the target vehicle until the accelerated drive torque is reached;

if the ADAS request is a braking request, determining a braking feedback torque corresponding to the target vehicle;

determining the brake control torque according to the actual driving torque corresponding to the target vehicle and the brake feedback torque;

and adjusting the actual braking torque corresponding to the target vehicle until the braking control torque is reached.

In one possible design, the control unit 505 is further specifically configured to, if the current state of the target vehicle is a parking control state, perform the following operations:

reducing the actual driving torque corresponding to the target vehicle according to a preset reduction driving rule;

if the actual driving torque corresponding to the target vehicle reaches a brake preset value, increasing the actual brake torque corresponding to the target vehicle according to a preset increase brake rule until the target vehicle stops;

determining a stopping braking torque when the target vehicle stops;

and adjusting the actual braking torque corresponding to the target vehicle to the stopping braking torque.

In one possible design, the control unit 505 is further specifically configured to, if the current state of the target vehicle is an emergency braking state, perform the following operations:

adjusting the actual driving torque corresponding to the target vehicle to zero;

and adjusting the actual braking torque corresponding to the target vehicle according to a preset emergency braking torque reduction rule until the speed of the target vehicle is zero.

In one possible design, the control unit 505 is further configured to:

determining a road surface adhesion coefficient of a current running road surface of the target vehicle according to the vehicle body signal corresponding to the target vehicle;

and carrying out feedback optimization on the control command corresponding to the target vehicle according to the road adhesion coefficient.

In one possible design, the feedback optimization of the control command corresponding to the target vehicle by the control unit 505 according to the road adhesion coefficient includes:

determining an actual acceleration estimation value corresponding to the target vehicle according to the road adhesion coefficient;

and carrying out feedback optimization along with the control instruction corresponding to the target vehicle according to the actual acceleration estimated value.

Fig. 6 is a schematic diagram of a hardware structure of a server according to an embodiment of the present disclosure, and as shown in fig. 6, a server 600 according to this embodiment includes at least one processor 601, at least one network interface 604 or other user interfaces 603, a memory 605, and at least one communication bus 602. The server 600 optionally contains a user interface 603 including a display, keyboard or pointing device. Memory 605 may comprise high-speed RAM memory, and may also include non-volatile memory (non-volatile memory), such as at least one disk memory. The memory 605 stores execution instructions, and when the server 600 operates, the processor 601 communicates with the memory 605, and the processor 601 calls the instructions stored in the memory 605 to execute the control method of the vehicle. The operating system 606, which contains various programs for implementing various basic services and for handling hardware-dependent tasks.

The server provided by the embodiment of the application can execute the technical scheme of the embodiment of the vehicle control method, the implementation principle and the technical effect are similar, and details are not repeated here.

The embodiment of the present application further provides a computer-readable medium, which includes a computer executable instruction, where the computer executable instruction enables a server to execute the vehicle control method described in the foregoing embodiment, and the implementation principle and the technical effect are similar, and are not described herein again.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A control method of a vehicle, characterized by comprising:

receiving an ADAS request corresponding to a target vehicle;

acquiring a vehicle body signal corresponding to the target vehicle;

2. The method of claim 1, wherein determining the control command corresponding to the target vehicle based on the ADAS request and the current state of the target vehicle comprises:

determining a braking torque corresponding to the target vehicle;

3. The method of claim 2, wherein the determining the braking torque corresponding to the target vehicle comprises:

determining the braking torque corresponding to the target vehicle by the following formula:

LoDC_BrkTrq_toESC＝max(100，20+abs(Ttq*n*i-m*g*slope*r))；

the method comprises the steps of obtaining a braking torque corresponding to a target vehicle, obtaining Ttq an engine torque of the target vehicle, obtaining n a transmission efficiency of the target vehicle, obtaining i a transmission ratio of the target vehicle, obtaining m a mass of the target vehicle, obtaining g a gravity acceleration, obtaining slope angle of a slope where the target vehicle is located at present, and obtaining r a wheel radius of the target vehicle.

4. The method according to claim 3, wherein if the current state of the target vehicle is a starting state, the controlling the target vehicle according to the control command corresponding to the target vehicle comprises:

5. The method according to any one of claims 1 to 4, wherein if the current state of the target vehicle is a driving state, the determining the control command corresponding to the target vehicle according to the driving torque corresponding to the target vehicle and the braking torque corresponding to the target vehicle comprises:

determining an accelerated driving torque corresponding to the acceleration request according to an actual driving torque corresponding to the target vehicle, the feedback torque and the steering wheel torque;

if the ADAS request is a braking request, determining a braking feedback moment corresponding to the target vehicle;

6. The method according to any one of claims 1 to 4, wherein if the current state of the target vehicle is a parking control state, the controlling the target vehicle according to the control command corresponding to the target vehicle comprises:

determining a stopping braking torque when the target vehicle stops;

7. The method according to any one of claims 1 to 4, wherein if the current state of the target vehicle is an emergency braking state, the controlling the target vehicle according to the control command corresponding to the target vehicle comprises:

8. The method according to any one of claims 1 to 4, further comprising:

9. The method of claim 8, wherein the feedback optimization of the control command corresponding to the target vehicle according to the road adhesion coefficient comprises:

10. A vehicle control apparatus characterized by comprising: