CN118182633A

CN118182633A - In-situ steering control method and device for distributed driving vehicle, vehicle and medium

Info

Publication number: CN118182633A
Application number: CN202410322540.5A
Authority: CN
Inventors: 刘益滔; 孙宇航; 李顺波; 胡成帅; 汪震隆; 孟祥科
Original assignee: Zhejiang Geely Holding Group Co Ltd; Geely Automobile Research Institute Ningbo Co Ltd
Current assignee: Zhejiang Geely Holding Group Co Ltd; Geely Automobile Research Institute Ningbo Co Ltd
Priority date: 2024-03-20
Filing date: 2024-03-20
Publication date: 2024-06-14

Abstract

The application provides a method, a device, a vehicle and a medium for controlling in-situ steering of a distributed driving vehicle, and relates to the technical field of vehicles. The system capacity limits include, among other things, torque limits, rotational speed limits, and available power limits. The technical scheme ensures the stability of the vehicle body in the in-situ steering process and reduces the turning radius.

Description

In-situ steering control method and device for distributed driving vehicle, vehicle and medium

Technical Field

The application relates to the technical field of vehicles, in particular to a method and a device for controlling in-situ steering of a distributed driving vehicle, the vehicle and a medium.

Background

The steering ability of a vehicle is one of the basic attributes of a vehicle, and the minimum turning radius of the vehicle is generally taken as an important parameter for checking the steering performance of an automobile. It characterizes to a large extent the ability of an automobile to pass through narrow curved zones or bypass non-surmountable obstacles. The in-situ steering is also called tank turning, and the in-situ turning function can be realized by independently distributing the torque of four wheels, so that the turning radius of the vehicle is reduced, and the trafficability is improved.

Currently, in order to achieve in-situ steering is typically achieved in combination with a chassis controller and a hydraulic braking system. Specifically, by locking part of the wheels, the turning around is realized by using other driving wheels. However, this approach can only provide a limited reduction in vehicle turning radius, and is less drivable, and the vehicle body can experience greater jerks.

Disclosure of Invention

The application provides a method and a device for controlling in-situ steering of a distributed driving vehicle, the vehicle and a medium, and aims to solve the problems of larger turning radius and poor driving feeling in-situ steering in the prior art.

In a first aspect, an embodiment of the present application provides a method for controlling in-situ steering of a distributed drive vehicle, including:

after detecting that the in-situ steering function is started, judging whether a preset in-situ steering activation condition is met according to the state of the vehicle;

If the vehicle meets the in-situ steering activation condition, determining the in-situ steering direction of the vehicle according to the steering angle of the steering wheel;

Calculating a target rotating speed difference of each wheel according to the opening degree of an accelerator pedal, the steering wheel angle and the actual wheel speed of each wheel;

Controlling the vehicle to perform in-situ steering according to the in-situ steering direction, the target rotating speed difference of each wheel, the attachment coefficient of each wheel and the preset system capacity limit; wherein the system capacity limit includes a torque limit, a rotational speed limit, and an available power limit.

In one possible design, the controlling the vehicle to steer in situ according to the steering in situ direction, the target speed difference of each wheel, the attachment coefficient of each wheel and the preset system capacity limit includes:

controlling the vehicle to perform in-situ steering according to the in-situ steering direction;

In the steering process of the vehicle, aiming at each wheel, according to the attachment coefficient of the wheel, the target yaw rate of the wheel and the target rotation speed difference of the wheel, acquiring a corrected first target torque;

Aiming at the wheels with the slip monitored in real time, determining a second target torque of the wheel slip rate according to the slip quantity of the wheels and the actual wheel speed;

Determining maximum rotation speed limiting torque of the motor corresponding to each wheel according to the rotation speed limit, calculating a real-time torque limiting value of the motor corresponding to each wheel according to the torque limit, the external characteristics of the motor and the current state, and determining maximum available torque and minimum available torque of the motor corresponding to each wheel limited by power according to the available power limit, the charge and discharge protection power of a battery and the charge and discharge efficiency of the battery;

For a motor of each wheel, determining a target request torque after limiting the motor according to a first target torque, a maximum rotation speed limiting torque, a real-time torque limiting value, a maximum available torque limited by power and a minimum available torque corresponding to the wheel;

the target requested torque is sent to an electric motor of the wheel.

In one possible design, the obtaining the corrected first target torque according to the attachment coefficient of the wheel, the target yaw rate of the wheel, and the target rotational speed difference of the wheel includes:

According to the attachment coefficient of the wheel, the target yaw rate of the wheel is inquired and obtained to obtain the target torque feedforward coefficient of the motor of the wheel;

PID adjustment is carried out according to the target rotating speed difference of the wheels, and a target torque original value of a motor of the wheels is obtained;

And correcting the original value of the target torque according to the feedforward coefficient of the target torque to obtain the corrected first target torque.

In one possible design, the determining, for the wheel in which slip is detected in real time, the second target torque of the wheel slip rate according to the slip amount of the wheel and the actual wheel speed includes:

during the steering process of the vehicle, monitoring whether each wheel slips in real time;

Triggering a target torque reducing request according to the slip quantity of each monitored wheel with slip;

Calculating to obtain control deviation according to the target wheel speed and the actual wheel speed of the wheel;

and performing PID adjustment according to the control deviation, and outputting the second target torque of the wheel slip rate.

In one possible design, the calculating the target rotation speed difference of each wheel according to the opening of the accelerator pedal, the steering wheel angle and the actual wheel speed of each wheel includes:

Inquiring a preset yaw rate comparison table according to the opening of the accelerator pedal to obtain a corresponding target yaw rate;

Acquiring a target rotating speed corresponding to a motor of each wheel according to the target yaw rate;

And calculating the target rotating speed difference of each wheel according to the target rotating speed and the actual rotating speed of the motor of each wheel.

In one possible design, the method further comprises:

Calculating a slip ratio of each wheel of a vehicle according to the acquired vehicle speed and the wheel speed of the wheel;

calculating an adhesion coefficient of the wheel according to the driving force of the wheel and the vertical load of the wheel;

And determining the attachment coefficient of the wheel according to the utilization attachment coefficient of the wheel and the slip rate of the wheel.

In one possible design, the determining whether the preset in-situ steering activation condition is satisfied according to the state of the vehicle includes:

Acquiring a non-associated fault zone bit, a safety condition zone bit and a state of a brake pedal of the vehicle;

and if the position of the unassociated fault mark is 1, the safety condition mark is also set to be 1, and the brake pedal is in a released state, determining that the vehicle meets the preset steering activation condition.

In a second aspect, an embodiment of the present application provides a steering-in-place control apparatus for a distributed drive vehicle, including:

the judging module is used for judging whether a preset in-situ steering activation condition is met according to the state of the vehicle after the in-situ steering function is detected to be started;

The determining module is used for determining the in-situ steering direction of the vehicle according to the steering angle of the steering wheel if the vehicle meets the in-situ steering activation condition;

The calculation module is used for calculating the target rotating speed difference of each wheel according to the opening degree of the accelerator pedal, the steering wheel angle and the actual wheel speed of each wheel;

the control module is used for controlling the vehicle to turn in situ according to the in-situ turning direction, the target rotating speed difference of each wheel, the attachment coefficient of each wheel and the preset system capacity limit; wherein the system capacity limit includes a torque limit, a rotational speed limit, and an available power limit.

In one possible design, the control module is specifically configured to:

the target requested torque is sent to an electric motor of the wheel.

In one possible design, the control module is specifically configured to:

In one possible design, the computing module is specifically configured to:

In one possible design, the computing module is further configured to:

In one possible design, the determining module is specifically configured to:

In a third aspect, an embodiment of the present application provides a vehicle including: a vehicle body and a vehicle controller;

wherein the vehicle controller includes a processor and a memory;

the memory stores computer-executable instructions;

the processor executes computer-executable instructions stored in the memory to implement the method as provided in the first aspect and each possible design.

In a fourth aspect, embodiments of the present application may provide a computer-readable storage medium having stored therein computer-executable instructions which, when executed by a processor, are adapted to carry out the method provided by the first aspect and each possible design.

According to the method, after the start of the in-situ steering function is detected, whether the in-situ steering activation condition is met is judged according to the state of the vehicle, if the in-situ steering activation condition is met, the in-situ steering direction of the vehicle is determined according to the turning angle of the steering wheel, the target speed difference of each wheel is calculated according to the opening of the accelerator pedal and the actual wheel speed of each wheel, and the in-situ steering is controlled according to the in-situ steering direction, the target speed difference of each wheel, the attachment coefficient of each wheel and the preset system capacity limit. The system capacity limits include, among other things, torque limits, rotational speed limits, and available power limits. In the technical scheme, the torque, the rotating speed and the available power of each wheel are controlled according to the preset system capacity limitation when the vehicle turns in situ, whether each wheel slips or not is monitored in real time, unexpected shaking or deviation of the rotating center of the motor at one wheel end or sudden torque is avoided, and therefore the problems that the turning radius and the vehicle body shake are overlarge and the driving feeling is poor in the prior art are effectively solved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.

FIG. 1 is a schematic representation of a conventional steering mode and a steer-in-place mode of the prior art;

FIG. 2 is a schematic diagram of a power topology of a prior art centralized drive and a distributed drive;

Fig. 3 is a schematic flow chart of a first embodiment of a method for controlling in-situ steering of a distributed driving vehicle according to an embodiment of the present application;

FIG. 4 is a schematic diagram illustrating the determination of the entry and exit conditions of the in-situ steering mode according to an embodiment of the present application;

Fig. 5 is a schematic flow chart of a second embodiment of a method for controlling in-situ steering of a distributed driving vehicle according to an embodiment of the present application;

fig. 6 is a schematic flow chart of a third embodiment of a method for controlling in-situ steering of a distributed driving vehicle according to an embodiment of the present application;

FIG. 7 is a schematic flow chart of determining the adhesion coefficient of the left front wheel according to an embodiment of the present application;

FIG. 8 is a schematic flow chart of a wheel slip rate control process according to an embodiment of the present application;

fig. 9 is a schematic flow chart of a fourth embodiment of a method for controlling in-situ steering of a distributed driving vehicle according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of a steering control device of a distributed driving vehicle according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a vehicle according to the present application.

Specific embodiments of the present application have been shown by way of the above drawings and will be described in more detail below. The drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but rather to illustrate the inventive concepts to those skilled in the art by reference to the specific embodiments.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Before describing the embodiments of the present application, an application background of the embodiments of the present application will be explained first:

The steering ability of a vehicle is one of the basic attributes of a vehicle, and the minimum turning radius of the vehicle is generally taken as an important parameter for checking the steering performance of an automobile. The minimum turning radius refers to the radius of a locus circle through which the center of the outer steering wheel rolls on the support plane when the steering wheel turns to the limit position and the vehicle is steered at the lowest steady vehicle speed. It characterizes to a large extent the ability of an automobile to pass through narrow curved zones or bypass non-surmountable obstacles. The smaller the turning radius, the better the automotive performance of the automobile.

The in-situ steering is also called tank turning, and because the tracks on the left side and the right side of the tank can reversely rotate, the tank can be helped to finish in-situ turning in a narrow space. Fig. 1 is a schematic representation of a conventional steering mode and a steering-in-place mode in the prior art. As shown in fig. 1, R is the turning radius and C is the center of rotation. In-situ steering (tank turning) can realize in-situ turning function by independently distributing the torque of four wheels, reduce the turning radius of the vehicle, improve the trafficability characteristic and realize the function without a hydraulic braking system or a four-wheel steering architecture. When the vehicle turns around the center of mass of the vehicle, the vehicle can rotate around the center of mass of the vehicle, and the requirements of special scenes such as in-situ obstacle avoidance and the like can be met.

At present, the implementation mode of the in-situ steering function mainly comprises a crawler type vehicle or an all-wheel steering vehicle with steering mechanisms additionally arranged on all wheels, but the crawler type vehicle is only used for special purposes, the application range is narrow, and the all-wheel steering vehicle is required to be additionally provided with an additional steering system, so that the cost of the vehicle and the complexity of a mechanical structure are increased, and meanwhile, higher requirements are also put forward on the control of a driving and steering system. Neither is suitable for passenger vehicle models.

For passenger vehicles, a centralized drive or a distributed drive configuration power system is typically employed. Fig. 2 is a schematic diagram of the power topology of a centralized drive and a distributed drive in the prior art. As shown in fig. 2, the distributed driving refers to a novel power form of driving 4 wheels by 4 motors respectively and independently, wherein the hub motor, the rim motor and the central distributed motor all belong to the power form of the distributed driving. The motor power output control device has the advantages of compact structure, short transmission chain, high power response speed, high control precision, high driving system efficiency and the like, and the functions of vehicle electronic differential speed, electric braking, vector control and the like can be skillfully realized through the accurate control of the motor power output of each wheel. Because of the characteristic of independent driving of the distributed driving 4 wheels, the left and right wheels can rotate reversely, and the vehicle can realize the in-situ steering function similar to tank turning.

The traditional central centralized driving vehicle type mostly depends on the hydraulic braking system to lock and slide the rear inner side wheel, so that the in-situ steering control of reducing the radius is realized, but the steering control is not truly a 0-radius tank, the reliability and the braking efficiency of the hydraulic braking system are highly dependent, a large number of calibration tests are required, and the defects of slow response, use field Jing Shouxian, poor driving experience and the like exist.

It can thus be derived that distributed driving has a better advantage in a u-turn-in-place scenario. However, not all distributed drive systems have four-wheel independent steering, that is, conventional vehicles based on mechanical differentials and not four-wheel independent steering cannot achieve in-situ turning around the center of mass of the vehicle. To address this problem, it is often done by combining a chassis controller and a hydraulic braking system. Specifically, by locking part of the wheels, the turning around is realized by using other driving wheels.

However, the scheme can only reduce the turning radius of the vehicle in a limited way, has poor driving feeling and can generate larger shaking of the vehicle body.

In view of the above problems, the inventors have found that, during the in-situ steering of a vehicle, when locking a part of the wheels, the driving force of the vehicle is unevenly distributed, and the part of the wheels are locked and cannot rotate, while the other wheels need to bear additional torque output, which causes torque differences in the vehicle and causes shaking and instability of the vehicle body. At the same time, the remaining rotatable wheels need to handle the steering of the entire vehicle. This may lead to a decrease in drivability and increase the difficulty of turning the vehicle, resulting in an increase in the radius of the turn. Based on the above, the application provides a in-situ steering control method for a distributed driving vehicle, which is used for controlling the torque, the rotating speed and the available power of each wheel according to the preset system capacity limit when the vehicle is in-situ steering, and monitoring whether each wheel slips in real time, so as to avoid unexpected shaking or deviation of the rotating center caused by abrupt change of the rotating speed or the torque of a motor at one wheel end, thereby effectively solving the problems of overlarge turning radius and vehicle body shaking and poor driving feeling in the prior art.

The technical scheme of the application is described in detail through specific embodiments.

It should be noted that the following embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

Fig. 3 is a flowchart illustrating an embodiment of a method for controlling in-situ steering of a distributed driving vehicle according to an embodiment of the present application. As shown in fig. 3, the in-situ steering control method of the distributed drive vehicle, which is applied to a vehicle equipped with 4-motor distributed drive, may include the steps of:

S31, judging whether a preset in-situ steering activation condition is met according to the state of the vehicle after the in-situ steering function is detected to be started.

In this scheme, when the user needs to turn around the vehicle, the user needs to perform a manual operation, and turn on the turn around function of the vehicle (some vehicles are also called turn around functions, and this scheme is not limited). When the vehicle detects that the in-situ steering function is started by a user, the state related to the safety condition, the fault condition and the like of the vehicle needs to be acquired to determine whether the current state of the vehicle meets the in-situ steering activation condition, and in-situ steering is performed only when the in-situ steering activation condition of the vehicle is met.

In a specific implementation, fig. 4 is a schematic diagram showing judgment of the entering and exiting conditions of the in-situ steering mode according to the embodiment of the present application, as shown in fig. 4, after a switch of the in-situ steering function (that is, a switch of the in-situ steering function) is turned on, that is, after the switch is set from 0 to 1, it needs to be judged whether a safety condition is satisfied, and under the condition that no associated fault flag bit is 1, and the safety condition flag bit is 1 and the in-situ steering switch is also 1, the state of the vehicle is determined, the in-situ steering activation condition is satisfied, the in-situ steering function of the vehicle is determined to be activated after the driver releases the brake pedal, and in-situ steering control is performed according to a subsequent process. When the safety condition is not met, or the driver actively presses the brake pedal, or the driver does not release the brake pedal, or the driver turns off the switch of the in-situ turning function, namely the in-situ turning switch is set to 0, or the condition that the related fault exists, the in-situ turning switch belongs to the condition that the in-situ turning activation condition is not met, and the driver needs to wait to turn off.

In one specific implementation, a vehicle's unassociated fault flag, safety condition flag, and brake pedal status are obtained. If the position of the unassociated fault mark is 1, the safety condition mark is also set to be 1, and the brake pedal is in a released state, the vehicle is determined to meet the preset steering activation condition.

In the specific implementation of this step, mainly the following implementation phases are included:

Waiting for activation: no associated fault flag = 1, safety condition flag = 1, turn around switch in place = 1, and driver depresses brake pedal

Confirmation of activation: in the in-situ turning activation condition, when the safety condition zone bit=1 and the unassociated fault signal=1 and the in-situ turning switch zone bit=1, the activation condition is determined to be met, the in-situ turning function is waited to be activated, and when a driver releases a brake pedal, the in-situ turning function is started to be activated. That is, while in the waiting-for-activation phase, the driver releases the brake pedal, and starts to activate the in-situ turning function, while in the confirmation-for-activation phase.

Waiting for shutdown:

Some safety conditions based on safety considerations are not met (such as vehicle speed, lateral acceleration, longitudinal acceleration, yaw rate, etc.).

Or the driver actively steps on the brake pedal;

or the driver actively turns off the switch with the in-situ turning function;

Or there is an associated failure.

At least one of the above cases is not in accordance with the condition of in-situ turning, and the activation phase is confirmed to be changed into the waiting closing phase

Closed state:

the absolute value of the actual yaw rate is smaller than a threshold value, which is a set value, and the waiting closing phase is changed to the closing phase.

The vehicle controller determines whether the current state of the vehicle satisfies the activation condition to wait for activation of the in-situ steering process or to wait for turning off of the in-situ steering function by the foregoing determination.

S32, if the vehicle meets the in-situ steering activation condition, determining the in-situ steering direction of the vehicle according to the turning angle of the steering wheel.

In this step, when the driver needs to turn in place, the steering wheel can be operated to turn in the direction in which the driver needs to turn around. The whole vehicle controller can acquire the rotation angle of the steering wheel, and then determines the in-situ steering direction required by the driver based on the degree or the size of the rotation angle.

In one particular implementation, a threshold value for the turn angle may be set, and when the turn angle of the steering wheel is greater than the absolute value of the threshold value, then a left turn is determined, that is, the direction of the in-situ turn is left turn. When the steering wheel angle is smaller than the negative threshold absolute value, then a right turn is determined, that is, the in-situ steering direction is right-hand.

S33, calculating the target rotation speed difference of each wheel according to the opening degree of the accelerator pedal and the actual wheel speed of each wheel.

In this step, when the vehicle is controlled to perform in-situ steering, different rotational speed differences are generated between the inner and outer wheels due to the power distribution of the vehicle and the limitation of the adhesion between the tires and the ground, and the target rotational speed difference is the ratio of the rotational speed difference between the inner and outer wheels to the rotational speed of the wheels themselves. By adjusting the target rotational speed difference, steering characteristics and stability control of the vehicle can be achieved. Therefore, it is also necessary to determine a target rotational speed difference of the vehicle before controlling the steering of the vehicle so that the steering stability of the vehicle is controlled in accordance therewith at the time of steering.

In one possible implementation, a plurality of lookup tables are pre-stored in the vehicle, each lookup table being used to characterize the mapping relationship between different parameters. The yaw rate map is used for representing a map between the accelerator pedal opening and the target yaw rate, and the target speed map is used for representing a map between the target yaw rate and the target speed. Thus, parameters required for controlling the steering of the vehicle can be queried in a table look-up mode. And inquiring a preset yaw rate comparison table according to the opening of the accelerator pedal to obtain a corresponding target yaw rate. And then, according to the target yaw rate, acquiring a target rotating speed corresponding to the motor of each wheel. And calculating the target rotating speed difference of each wheel according to the target rotating speed and the actual rotating speed of each wheel.

Alternatively, the accelerator pedal opening may be obtained by an in-vehicle electronic terminal (IHU soft switch) or a mechanical device (accelerator pedal).

By way of example, the yaw rate map may be represented by table 1.

TABLE 1

	1	2	3	4	5	6	7	8	9	10	11
												Throttle pedal opening	0	10	20	30	40	50	60	70	80	90	100
Target yaw rate	0	0.2	0.4	0.6	0.8	1	1.2	1.4	1.6	1.8	2

In one specific implementation, the target speed difference for each wheel may be calculated according to the following equation.

N_{dif_FL}＝N_{Tgt_FL}-N_{Act_FL}

N_{dif_FR}＝N_{Tgt_FR}-N_{Act_FR}

N_{dif_RL}＝N_{Tgt_RL}-N_{Act_RL}

N_{dif_RR}＝N_{Tgt_RR}-N_{Act_RR}

In the above formula, N _{dif_FL},N_{Tgt_FL},N_{Act_FL} is the target rotation speed difference, the target rotation speed and the actual rotation speed of the front left motor respectively; n _{dif_FR},N_{Tgt_FR},N_{Act_FR} are respectively the target rotation speed difference, the target rotation speed and the actual rotation speed of the right front motor; n _{dif_RL},N_{Tgt_RL},N_{Act_RL} are respectively the target rotation speed difference, the target rotation speed and the actual rotation speed of the left rear motor; n _{dif_RR},N_{Tgt_RR},N_{Act_RR} are respectively the target rotation speed difference, the target rotation speed and the actual rotation speed of the right rear motor.

S34, controlling the vehicle to steer in situ according to the steering direction in situ, the target rotation speed difference of each wheel, the attachment coefficient of each wheel and the preset system capacity limit.

In this step, the vehicle may be controlled to steer in situ according to the steering in situ direction, and in the steering in situ process, the steering process of the vehicle may be controlled according to the target rotational speed difference of the wheels, the attachment coefficient of each wheel, and the preset system capacity limit. The system capacity limits include, among other things, torque limits, rotational speed limits, and available power limits.

It should be understood that the specific control process of the vehicle during the in-situ steering in this step may refer to the embodiment shown in fig. 5, and will not be described in detail herein.

According to the in-situ steering control method for the distributed driving vehicle, after the in-situ steering function is detected to be started, whether a preset in-situ steering activation condition is met is judged according to the state of the vehicle, if the in-situ steering activation condition is met, the in-situ steering direction of the vehicle is determined according to the rotation angle of the steering wheel, the target rotation speed difference of each wheel is calculated according to the opening degree of the accelerator pedal and the actual wheel speed of each wheel, and the in-situ steering is controlled according to the in-situ steering direction, the target rotation speed difference of each wheel, the attachment coefficient of each wheel and the preset system capacity limit. The system capacity limits include, among other things, torque limits, rotational speed limits, and available power limits. In the technical scheme, the torque, the rotating speed and the available power of each wheel are controlled according to the preset system capacity limitation when the vehicle turns in situ, whether each wheel slips or not is monitored in real time, unexpected shaking or deviation of the rotating center of the motor at one wheel end or sudden torque is avoided, and therefore the problems that the turning radius and the vehicle body shake are overlarge and the driving feeling is poor in the prior art are effectively solved.

Fig. 5 is a schematic flow chart of a second embodiment of a method for controlling in-situ steering of a distributed driving vehicle according to an embodiment of the present application. As shown in fig. 5, S34 may be implemented by:

S51, controlling the vehicle to perform in-situ steering according to the in-situ steering direction.

S52, acquiring a corrected first target torque according to the attachment coefficient of each wheel, the target yaw rate of the wheel and the target rotation speed difference of the wheel in the steering process of the vehicle.

In this step, the target driving torque also needs to be corrected in accordance with the attachment coefficient of the wheels, considering that the driving torque required for the low road surface is small.

In one specific implementation, a target torque feedforward coefficient map is stored in the vehicle, the target torque feedforward coefficient map representing a map between the attachment coefficient, the target yaw rate, and the target torque feedforward coefficient. And according to the attachment coefficient of the wheel, the target yaw rate of the wheel, and inquiring and acquiring the target torque feedforward coefficient of the motor of the wheel. PID adjustment is carried out according to the target rotating speed difference of the wheels, and a target torque original value of the motor of the wheels is obtained. And correcting the original value of the target torque according to the feedforward coefficient of the target torque to obtain a corrected first target torque.

Illustratively, the target torque feedforward coefficient map may be represented by table 2.

TABLE 2

	0	0.1	0.2	0.3	0.4	0.5	0.6	0.7	0.8	0.9	1
												-5	0.32	0.32	0.32	0.48	0.64	0.81	0.95	1.09	1.23	1.37	1.51
-4	0.32	0.32	0.32	0.48	0.64	0.81	0.95	1.09	1.23	1.37	1.51
												-3.2	0.32	0.32	0.32	0.48	0.64	0.81	0.95	1.09	1.23	1.37	1.51
-2.4	0.32	0.32	0.32	0.48	0.64	0.81	0.95	1.09	1.23	1.37	1.51
												-1.6	0.31	0.31	0.31	0.47	0.63	0.8	0.94	1.08	1.22	1.36	1.5
-0.8	0.31	0.31	0.31	0.47	0.63	0.8	0.94	1.08	1.22	1.36	1.5
												0	0.25	0.25	0.25	0.41	0.57	0.73	0.87	1.01	1.15	1.29	1.43
0.8	0.31	0.31	0.31	0.47	0.63	0.8	0.94	1.08	1.22	1.36	1.5
												1.6	0.31	0.31	0.31	0.47	0.63	0.8	0.94	1.08	1.22	1.36	1.5
2.4	0.32	0.32	0.32	0.48	0.64	0.81	0.95	1.09	1.23	1.37	1.51
												3.2	0.32	0.32	0.32	0.48	0.64	0.81	0.95	1.09	1.23	1.37	1.51
4	0.32	0.32	0.32	0.48	0.64	0.81	0.95	1.09\|	1.23	1.37	1.51
												5	0.32	0.32	0.32	0.48	0.64	0.81	0.95	1.09	1.23	1.37	1.51

In table 2, the first column is the target yaw rate, and the first column is the attachment coefficient.

And S53, aiming at the wheels with the slip in real time, determining a second target torque of the wheel slip rate according to the slip quantity of the wheels and the actual wheel speed.

In this step, the vehicle is required to reverse rotation at low speed due to the in-situ steering, which reduces the friction of the wheels on the ground. Therefore, in the steering process, particularly in the case of low-speed running or low road friction, the wheels are easy to slip, the second target torque of the wheel slip rate is determined according to the slip condition of the wheels, the problem that the rotation speed or torque of a motor at one wheel end suddenly changes, unexpected shaking is generated or the rotation center is deviated is avoided,

In one possible implementation, each wheel is monitored in real time for slip during vehicle steering. And triggering a target torque reducing request according to the slip quantity of each wheel with the monitored slip. And calculating the control deviation according to the target wheel speed and the actual wheel speed of the wheel. And PID adjustment is carried out according to the control deviation, and a second target torque of the wheel slip rate is output.

Where control deviation = target wheel speed-actual wheel speed (CtrlDif = WHLSPDTAR _mps-WHLSPDACT _mps).

The PID adjustment is performed according to the control deviation, and the second target torque of the slip rate of the output wheel can be realized through the following formula:

In the above formula, T _{slip_Max} is the maximum target torque request of the wheel slip control limitation, T _{slip_Min} is the minimum target torque request of the wheel slip control limitation, K _p is the first scale factor, ctrlDif is the control deviation, K _i is the first integral factor, K _d is the first differential factor, P is the first scale factor, I is the second integral factor, and D is the second differential factor.

And S54, determining the maximum rotation speed limiting torque of the motor corresponding to the wheel according to the rotation speed limit, calculating a real-time torque limiting value of the motor corresponding to the wheel according to the torque limit, the external characteristics of the motor and the current state, and determining the maximum available torque and the minimum available torque of the motor corresponding to the wheel limited by the power according to the available power limit, the charge and discharge protection power of the battery and the charge and discharge efficiency of the battery.

In this step, the power-limited wheels are referred to as inboard rear wheels (or inboard front wheels in a reverse-steered vehicle) during in-situ steering of the vehicle. Power-limited wheels are prone to slip because of their low friction with the ground and limited adhesion. Slip may cause wheels to rotate but may not effectively transmit driving force or braking force, thereby affecting the steering ability and stability of the vehicle. To ensure that the torque distribution can be adjusted within a reasonable range to provide stable handling performance and to ensure safe and good steering operation, it is necessary to determine the maximum available torque and the minimum available torque of the power-limited wheel-corresponding motor.

The system capacity limiting function is to protect the driving motor and the power battery from damage caused by the limit conditions such as overload of the system conditions, including torque limitation, rotation speed limitation and available power limitation. Next, these three aspects will be described in detail.

And (5) rotation speed limitation: determining the maximum rotation speed limit torque of the motor corresponding to the wheel according to the rotation speed limit

The in-situ steering process needs to ensure the stability of the vehicle body and avoid eccentricity, and does not need an excessively high rotating speed, so that the rotating speed of the wheel end needs to be limited. And the closed loop control of the actual rotating speed absolute value of the motor and the maximum rotating speed threshold of the in-situ steering mode is considered, so that torque abrupt change caused by too fast change of the rotating speed of the motor is prevented. And when the maximum value of the absolute values of the four motor speeds exceeds the threshold value, PID control is carried out on the deviation part exceeding the threshold value, so that the motor speed is prevented from exceeding the limit value.

Calculating the maximum limit rotation speed deviation of each motor according to the following formula:

In the above formula, N _{Mot_limit} is the maximum rotation speed limit value of the motor; n _err is the deviation of the over-limit rotating speed, For the torque actually output by the left front wheel,/>For the torque actually output by the right front wheel,/>For the torque actually output by the left rear wheel,/>Which is the torque actually output by the right rear wheel.

And carrying out third PID adjustment according to the overrun speed deviation, and outputting the maximum speed limit torque of each motor:

in the above formula, T _{N_lim_Max} is the maximum available torque of each motor limited by the rotating speed, T _{N_lim_Min} is the minimum available torque of each motor limited by the rotating speed, and K _i is the integral gain coefficient;

Torque limitation: and calculating a real-time torque limit value of the corresponding motor of the wheel according to the torque limit, the external characteristics of the motor and the current state.

Available power limit: and determining the maximum available torque and the minimum available torque of the motor corresponding to the wheels limited by the power according to the available power limit, the charge and discharge protection power of the battery and the charge and discharge efficiency of the battery.

The maximum available torque and the minimum available torque of the corresponding motor of the wheels limited by power are calculated according to the following formula:

In the above formula, T _{P_Max} is the maximum available torque of the wheel corresponding motor limited by power, and T _{P_Min} is the minimum available torque of the wheel corresponding motor limited by power; p _{bat_dischg} is the charge-discharge protection power of the battery, and P _{bat_charg} is the charge-discharge efficiency of the battery; n _{Act_mot} is the actual rotation speed of the motor; η _dischg is the discharge efficiency of the motor, and η _charg is the charge efficiency of the motor.

S55, aiming at the motor of each wheel, determining the target request torque after the motor limitation according to the first target torque, the second target torque, the maximum rotation speed limiting torque, the real-time torque limiting value, the maximum available torque limited by power and the minimum available torque corresponding to the wheels.

In this step, for each wheel motor, the target requested torque after motor limitation is arbitrated based on the calculated motor system capacities (first target torque, second target torque, maximum rotational speed limitation torque, real-time torque limitation value, maximum available torque limited by power, and minimum available torque) described above.

In practical applications, the in-situ steering process needs to ensure that the actual yaw torque is 0, and when a single motor torque limit occurs, torque limiting and transfer strategies need to be implemented in order to avoid the occurrence of unintended yaw torque.

Illustratively, taking the left front wheel motor activation slip limit as an example, each motor torque limit, transfer and arbitration calculations are as follows:

and step 1, torque transfer and distribution are carried out on the basis of motor request torque controlled by the slip of the left front wheel. Next, an example of one torque transfer is described, but it should be understood that the transfer is not limited to one.

Wherein the target requested torque for each of the motors after transfer may be determined by:

T_{Tsf_FL}＝T_{Raw_FL}-T_{SlipMax_FL}

T_{01_FL}＝T_{SlipMax_FL}

T_{01_FR}＝T_{Raw_FR}-|T_{SlipMax_FL}|

T_{01_RL}＝T_{Raw_RL}+|T_{SlipMax_FL}|

T_{01_RR}＝-T_{SlipMax_FL}

In the above formula, T _{Tsf_FL} is the torque to be transferred after the motor of the left front wheel is limited; t _{Raw_FL} is the first target torque for the left front wheel motor, T _{SlipMax_FL} is the maximum target torque for the left front wheel limited by the wheel slip control, T _{01_FL} is the target torque for the motor for the left front wheel after the first transfer, T _{01_FR} is the target torque for the motor for the right front wheel after the first transfer, T _{01_RL} is the target torque for the motor for the left rear wheel after the first transfer, and T _{01_RR} is the target torque for the motor for the right rear wheel after the first transfer.

And 2, calculating the target request torque after limiting each motor according to the calculated motor system capacity.

In the above formula, T _{Req_FL} is the target torque after motor limitation of the left front wheel, T _{Req_FR} is the target torque after motor limitation of the right front wheel, T _{Req_RL} is the target torque after motor limitation of the left rear wheel, and T _{Req_RR} is the target torque after motor limitation of the right rear wheel.

And S56, transmitting the target request torque to the motor of the wheel.

In the above embodiment, the in-situ steering function is implemented according to the motor rotation speed control closed-loop principle by taking strategies such as vehicle state monitoring, parameter estimation, vehicle dynamics model, energy management and the like as control theoretical bases, specifically, the target rotation speeds of the motors are obtained according to the target yaw angular speeds of the vehicles, and the target torque original values of the motors are obtained by PID control according to the target rotation speeds of the motors and a feedforward algorithm. Meanwhile, wheel slip rate control is added in the process of controlling the vehicle to perform in-situ steering, so that vehicle shaking or unexpected offset caused by motor speed galloping or torque abrupt change due to slip of low attached wheels is avoided. In addition, after a wheel has a motor capability limit, the same limit is applied to the opposite wheel, so that additional yaw torque around the limited wheel is avoided, and the in-situ steering center position of the vehicle is offset. And meanwhile, the limited motor capacity is transferred to the wheel on the other side of the coaxial shaft, so that the in-situ steering driving force required by a driver can be continuously output.

Next, calculation of the adhesion coefficient of the wheel will be explained.

Fig. 6 is a schematic flow chart of a third embodiment of a method for controlling in-situ steering of a distributed driving vehicle according to an embodiment of the present application. As shown in fig. 6, the slip ratio of each wheel can be calculated by:

S61, calculating a slip ratio of the wheel from the acquired vehicle speed and wheel speed of the wheel for each wheel of the vehicle.

In this step, since it is necessary to correct the utilization adhesion coefficient of each wheel of the vehicle based on the slip ratio of that wheel later, the corresponding adhesion coefficient is obtained. Therefore, it is necessary to calculate the slip ratio of each wheel of the vehicle first.

In one possible implementation, the wheel speed of each wheel may be collected by a wheel speed sensor. For each wheel of the vehicle, a converted wheel speed of the wheel is calculated according to a reference vehicle speed, and then a slip ratio of the wheel is calculated based on the converted wheel speed of the wheel and the collected wheel speed of the wheel. The reference vehicle speed is the acquired vehicle speed.

In the above-described implementation, the converted wheel speed and slip ratio of each wheel may be calculated by the following formulas.

/>

In the above formula, V _{Wl_FL} represents the wheel speed of the left front wheel, V _{Wl_FR} represents the wheel speed of the right front wheel, V _{Wl_RL} represents the wheel speed of the left rear wheel, and V _{Wl_RR} represents the wheel speed of the right rear wheel; v _x is centroid speed; d _f represents the front wheel track, d _r represents the rear wheel track; l _f is the distance from the centroid to the front axis; delta is the tire rotation angle.

In the above, S _FL is the slip rate of the left front wheel, and V _FL is the wheel speed of the left front wheel collected by the wheel speed sensor; s _FR is the slip rate of the right front wheel, and V _FR is the wheel speed of the right front wheel acquired by the wheel speed sensor; s _RL is the slip rate of the left rear wheel, and V _RL is the wheel speed of the left rear wheel acquired by the wheel speed sensor; s _RR is the slip rate of the right rear wheel, and V _RR is the wheel speed of the right rear wheel acquired by the wheel speed sensor.

S62, calculating the utilization adhesion coefficient of the wheel according to the driving force of the wheel and the vertical load of the wheel.

In this step, the utilization attachment coefficient of each wheel may be obtained by dividing the driving force of each wheel by the vertical load of each wheel, and the specific calculation formula is as follows:

Mu _FL is the utilization adhesion coefficient of the left front wheel, F _x,FL is the driving force of the left front wheel, F _z,FL is the vertical load of the left front wheel, mu _FR is the utilization adhesion coefficient of the right front wheel, F _x,FR is the driving force of the right front wheel, F _z,FR is the vertical load of the right front wheel, mu _RL is the utilization adhesion coefficient of the left rear wheel, F _x,RL is the driving force of the left rear wheel, F _z,RL is the vertical load of the left rear wheel, mu _RR is the utilization adhesion coefficient of the right rear wheel, F _x,RR is the driving force of the right rear wheel, F _z,RR is the vertical load of the right rear wheel.

S63, determining the attachment coefficient of the wheel according to the utilization attachment coefficient of the wheel and the slip rate of the wheel.

In this step, since the utilization adhesion coefficient of the wheel is lower than the adhesion coefficient of the wheel (i.e., road adhesion coefficient) under certain conditions, it is also necessary to correct the utilization adhesion coefficient of the wheel based on the slip ratio of the wheel. Wherein the attachment coefficient of the vehicle includes an attachment coefficient of each wheel.

Taking the left front wheel as an example, a description will be given of a manner in which the attachment coefficient of the left front wheel is determined based on the slip ratio of the left front wheel and the utilization attachment coefficient.

Fig. 7 is a schematic flow chart of determining an adhesion coefficient of a front left wheel according to an embodiment of the present application. As shown in fig. 7, the determination process of the attachment coefficient of the left front wheel may include the steps of:

s71: and judging whether the left front wheel slip rate is greater than a threshold value.

The threshold is the slip ratio at wheel slip.

If the left front wheel slip ratio is greater than the threshold, then S72 is executed; otherwise, S74 is performed.

S72: and updating the left front wheel attachment coefficient to the left front wheel utilization attachment coefficient.

Further, if the left front wheel slip ratio is smaller than the threshold value and the left front wheel attachment coefficient of the previous cycle is larger than the left front wheel utilization attachment coefficient, S73 is executed: if the left front wheel slip ratio is greater than the threshold value and the latched left front wheel attachment coefficient is smaller than the utilization attachment coefficient, S74 is performed.

S73, sealing and storing the left front wheel attachment coefficient.

Further, if the left front wheel slip ratio is greater than the threshold value, S72 is executed, and if the latched left front wheel attachment coefficient is smaller than the utilization attachment coefficient, S74 is executed.

S74, left front wheel attachment coefficient=left front wheel use attachment coefficient×correction coefficient.

Further, if the left front wheel slip ratio is greater than the threshold value, S72 is executed.

In the steering process, the wheel slip rate control monitors whether each wheel slips in real time, calculates a target torque reducing request according to the slip quantity of the wheels, and avoids unexpected shaking or rotation center deviation caused by abrupt change of the rotating speed or the torque of a motor at a certain wheel end. Specifically, the wheel slip rate control process refers to fig. 8.

Fig. 8 is a schematic flow chart of a wheel slip rate control process according to an embodiment of the present application. As shown in fig. 8, the wheel slip rate control process may include the steps of:

S81, judging whether the actual wheel speed of each wheel is larger than the target wheel speed or not according to each wheel.

If yes, then execution S82; if not, the wheel speed of the wheel is monitored.

S82, judging whether the first target torque is equal to the control deviation multiplied by PID control.

If yes, executing S83; if not, then control deviation = target wheel speed-actual wheel speed is determined.

S83, judging whether the actual torque is equal to the target torque.

If yes, then execution S84; if not, triggering a target torque reduction request.

S84, judging whether the control deviation is equal to 0.

If yes, the wheel slip rate control is exited, and if not, S81 is executed.

The method of controlling the in-situ steering of the distributed drive vehicle according to any one of the above embodiments will be explained below by way of a specific example.

Fig. 9 is a flowchart of a fourth embodiment of a method for controlling in-situ steering of a distributed driving vehicle according to an embodiment of the present application. As shown in fig. 9, the in-situ steering control method of the distributed drive vehicle may include the steps of:

And step 1, judging whether the in-situ steering activation condition is met according to the in-situ steering enabling condition.

And 2, determining the in-situ steering direction of the vehicle when the in-situ steering activation condition is met.

The in-situ steering direction is in-situ left steering or in-situ right steering.

And step 3, responding to the input operation of a driver, and acquiring the opening degree of an accelerator pedal and steering of a steering wheel.

And 4, calculating the target yaw rate according to the opening of the accelerator pedal and the steering of the steering wheel.

And 5, acquiring state parameters of the electric drive system.

The electric drive system state parameters comprise a motor mode, an actual rotating speed, an actual torque and a fault level.

And 6, correcting the wheel speed of the driving motor according to the state parameters of the electric drive system, and outputting the actual wheel speed of the left front wheel, the actual wheel speed of the left rear wheel, the actual wheel speed of the right front wheel and the actual wheel speed of the right rear wheel.

And 7, acquiring the state parameters of the whole vehicle.

The vehicle state parameters comprise actual vehicle speed, battery charge and discharge power, battery SOC and parameters acquired by an IMU sensor.

And 8, calculating the attachment coefficient of the left front wheel, the attachment coefficient of the left rear wheel, the attachment coefficient of the right front wheel and the attachment coefficient of the right rear wheel according to the state parameters of the whole vehicle.

And 9, calculating the target rotating speed of the left front wheel, the target rotating speed of the left rear wheel, the target rotating speed of the right front wheel and the target rotating speed of the right rear wheel according to the in-situ steering direction, the target yaw rate and the actual wheel speeds of the wheels.

And 10, correcting the target rotating speed of each wheel by the PID controller through a feedforward coefficient to obtain a first target torque of the left front wheel, a first target torque of the left rear wheel, a first target torque of the right front wheel and a first target torque of the right rear wheel.

And 11, controlling the wheel slip rate according to the attachment coefficient of each wheel, and determining a torque reducing request.

The torque reducing request can be a torque reducing request of a left front wheel, a torque reducing request of a left rear wheel, a torque reducing request of a right front wheel and a torque reducing request of a right rear wheel.

And step 12, carrying out arbitration, limitation and transfer operation on the torque of each wheel according to the torque reduction request, the first target torque of each wheel and the system capacity limitation, and obtaining the target request torque of the left front wheel, the target request torque of the left rear wheel, the target request torque of the right front wheel and the target request torque of the right rear wheel.

The system capacity limits include, among other things, torque limits, rotational speed limits, and available power limits.

The following are examples of the apparatus of the present application that may be used to perform the method embodiments of the present application. For details not disclosed in the embodiments of the apparatus of the present application, please refer to the embodiments of the method of the present application.

Fig. 10 is a schematic structural diagram of a steering control device for a distributed driving vehicle according to an embodiment of the present application. As shown in fig. 10, the in-situ steering control device 100 of the distributed drive vehicle includes:

the judging module 101 is configured to judge whether a preset in-situ steering activation condition is satisfied according to a state of the vehicle after detecting that the in-situ steering function is turned on.

A determining module 102 is configured to determine a steering-in-place direction of the vehicle based on the steering angle of the steering wheel if the vehicle satisfies the steering-in-place activation condition.

And the calculating module 103 is used for calculating the target rotating speed difference of each wheel according to the opening degree of the accelerator pedal, the steering wheel angle and the actual wheel speed of each wheel.

The control module 104 is configured to control the vehicle to steer in situ according to the steering direction, the target speed difference of each wheel, the attachment coefficient of each wheel, and a preset system capacity limit. The system capacity limits include, among other things, torque limits, rotational speed limits, and available power limits.

In one possible design, the control module 104 is specifically configured to:

and controlling the vehicle to perform in-situ steering according to the in-situ steering direction.

In the steering process of the vehicle, for each wheel, a corrected first target torque is acquired according to the attachment coefficient of the wheel, the target yaw rate of the wheel and the target rotation speed difference of the wheel.

And determining a second target torque of the wheel slip rate according to the slip quantity of the wheels and the actual wheel speed aiming at the wheels with the slip in real time.

And determining the maximum rotation speed limiting torque of the motor corresponding to the wheel according to the rotation speed limit aiming at the motor of each wheel, calculating a real-time torque limiting value of the motor corresponding to the wheel according to the torque limit, the external characteristics of the motor and the current state, and determining the maximum available torque and the minimum available torque of the motor corresponding to the wheel limited by the power according to the available power limit, the charge and discharge protection power of the battery and the charge and discharge efficiency of the battery.

And determining the target request torque after limiting the motor according to the first target torque, the maximum rotation speed limiting torque, the real-time torque limiting value, the maximum available torque limited by power and the minimum available torque corresponding to the wheels aiming at the motor of each wheel.

The target requested torque is sent to the motor of the wheel.

In one possible design, the control module 104 is specifically configured to:

And according to the attachment coefficient of the wheel, the target yaw rate of the wheel, and inquiring and acquiring the target torque feedforward coefficient of the motor of the wheel.

PID adjustment is carried out according to the target rotating speed difference of the wheels, and a target torque original value of the motor of the wheels is obtained.

And correcting the original value of the target torque according to the feedforward coefficient of the target torque to obtain a corrected first target torque.

In one possible design, the control module 104 is specifically configured to:

During the steering process of the vehicle, whether each wheel slips or not is monitored in real time.

And triggering a target torque reducing request according to the slip quantity of each wheel with the monitored slip.

And calculating the control deviation according to the target wheel speed and the actual wheel speed of the wheel.

And PID adjustment is carried out according to the control deviation, and a second target torque of the wheel slip rate is output.

In one possible design, the computing module 103 is specifically configured to:

And inquiring a preset yaw rate comparison table according to the opening of the accelerator pedal to obtain a corresponding target yaw rate.

And acquiring a target rotating speed corresponding to the motor of each wheel according to the target yaw rate.

In one possible design, the computing module 103 is further configured to:

For each wheel of the vehicle, a slip ratio of the wheel is calculated from the acquired vehicle speed and wheel speed of the wheel.

The utilization attachment coefficient of the wheel is calculated based on the driving force of the wheel and the vertical load of the wheel.

In one possible design, the determining module 101 is specifically configured to:

and acquiring the unassociated fault zone bit, the safety condition zone bit and the state of a brake pedal of the vehicle.

If the position of the unassociated fault mark is 1, the safety condition mark is also set to be 1, and the brake pedal is in a released state, the vehicle is determined to meet the preset steering activation condition. The in-situ steering control device for the distributed driving vehicle provided by the embodiment of the application can be used for executing the in-situ steering control method for the distributed driving vehicle in any embodiment, and the implementation principle and the technical effect are similar and are not repeated here.

It should be noted that, it should be understood that the division of the modules of the above apparatus is merely a division of a logic function, and may be fully or partially integrated into a physical entity or may be physically separated. And these modules may all be implemented in software in the form of calls by the processing element; or can be realized in hardware; the method can also be realized in a form of calling software by a processing element, and the method can be realized in a form of hardware by a part of modules. In addition, all or part of the modules may be integrated together or may be implemented independently. The processing element described herein may be an integrated circuit having signal processing capabilities. In implementation, each step of the above method or each module above may be implemented by an integrated logic circuit of hardware in a processor element or an instruction in a software form.

Fig. 11 is a schematic structural diagram of a vehicle according to the present application. Referring to fig. 11, the vehicle includes: a vehicle body 111 and a vehicle controller 112;

wherein the vehicle controller 112 includes a processor 1121 and a memory 1122;

Memory 1122 stores computer-executable instructions;

The processor 1121 executes computer-executable instructions stored in a memory to implement the in-situ steering control method of the distributed drive vehicle of any of the method embodiments described above.

The vehicle provided by the embodiment of the application is used for realizing the technical scheme shown in the embodiment of the method, and the implementation principle and the beneficial effects are similar, and are not repeated here.

Embodiments of the present application provide a computer-readable storage medium having stored therein computer-executable instructions that, when executed on a computer, cause the computer to perform the above-described in-situ steering control method of a distributed drive vehicle.

The computer readable storage medium described above may be implemented by any type of volatile or non-volatile memory device or combination thereof, such as static random access memory, electrically erasable programmable read-only memory, magnetic memory, flash memory, magnetic disk or optical disk. A readable storage medium can be any available medium that can be accessed by a general purpose or special purpose computer.

In the alternative, a readable storage medium is coupled to the processor such that the processor can read information from, and write information to, the readable storage medium. In the alternative, the readable storage medium may be integral to the processor. The processor and the readable storage medium may reside in an Application SPECIFIC INTEGRATED Circuits (ASIC). The processor and the readable storage medium may reside as discrete components in a device.

Embodiments of the present application also provide a computer program product comprising a computer program stored on a computer readable storage medium, from which at least one processor can read, the at least one processor executing the computer program can implement the above-described method of controlling in-situ steering of a distributed drive vehicle.

It is to be understood that the application is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

1. A method of controlling in-situ steering of a distributed drive vehicle, comprising:

2. The method of claim 1, wherein controlling the vehicle to steer in situ based on the steer-in-place direction, the target speed differential for each wheel, the attachment coefficient for each wheel, and a preset system capacity limit, comprises:

the target requested torque is sent to an electric motor of the wheel.

3. The method according to claim 2, wherein the obtaining the corrected first target torque from the target yaw rate of the wheel, the target rotational speed difference of the wheel, based on the attachment coefficient of the wheel, includes:

4. The method of claim 2, wherein determining the second target torque for the wheel slip rate based on the slip amount of the wheel and the actual wheel speed for the wheel in which slip is detected in real time comprises:

5. The method according to any one of claims 1 to 4, wherein calculating the target rotation speed difference of each wheel from the accelerator pedal opening, the steering wheel angle, and the actual wheel speed of each wheel, respectively, comprises:

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

7. The method according to any one of claims 1 to 4, wherein the determining whether a preset in-situ steering activation condition is satisfied according to the state of the vehicle itself includes:

8. A in-situ steering control device of a distributed drive vehicle, characterized by comprising:

9. A vehicle, characterized by comprising: a vehicle body and a vehicle controller;

wherein the vehicle controller includes a processor and a memory;

the memory stores computer-executable instructions;

the processor executes computer-executable instructions stored in the memory to implement the method of any one of claims 1 to 7.

10. A computer readable storage medium having stored therein computer executable instructions which when executed by a processor are adapted to carry out the method of any one of claims 1 to 7.