Cooperative control method, device and equipment for vehicle steering

Abstract

The invention discloses a cooperative control method, device and equipment for vehicle steering, and the method comprises the steps: firstly carrying out the linearization processing of a vehicle dynamics model constructed through the physical parameters of a target vehicle through the real-time operation parameters of the target vehicle, and obtaining a linearized model; carrying out discretization and differentiation treatment on the model to obtain a differentiated model; according to the driving intention of a target driver on the target vehicle, the real-time state target value of steering of the target vehicle is calculated, and the steady-state feedforward control quantity of the target vehicle is calculated through the real-time state target value and the linearized model. And the feedback control quantity of the target vehicle is calculated based on the LQR by using the real-time state target value and the differentiated model, and then the accumulated sum of the steady-state feed-forward control quantity and the feedback control quantity is used as the output control quantity of an actuator corresponding to the target vehicle to perform cooperative control on steering of the target vehicle so as to realize the driving intention of a target driver. The control effect and the driving experience are improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a coordinated control method, device and equipment for vehicle steering. Background Art

[0002] With the improvement of people's living standards and the rapid development of social economy, the use rate of cars has gradually increased, and more and more cars have entered people's lives, bringing great convenience to all aspects of people's lives. Among them, how to improve the user's driving and riding experience and ensure the safety and stability of vehicle driving is particularly important.

[0003] At present, vehicles often experience understeer or oversteer when turning, and cannot fully track the user's driving intention. In this regard, the existing control method is to activate the Vehicle Dynamic Control (VDC) function, by adding braking force to one of the vehicle's wheels, thereby changing the vehicle's yaw rate to improve the problem of inaccurate vehicle steering. However, this control method can only complete the vehicle's stability control by applying braking force to a single wheel of the vehicle, and during the activation of VDC, the longitudinal speed of the vehicle cannot be guaranteed, which violates the user's driving intention and reduces the user's driving experience. Summary of the invention

[0004] The main purpose of the embodiments of the present application is to provide a method, device and equipment for collaborative control of vehicle steering, which can achieve collaborative control of vehicle steering, thereby minimizing the driver's subjective perception of active intervention while ensuring following the driver's driving intention, thereby improving the vehicle's steering control effect and the driver's driving experience.

[0005] The embodiment of the present application provides a coordinated control method for vehicle steering, including:

[0006] Acquiring vehicle physical parameters of a target vehicle to be controlled, and constructing a vehicle dynamics model using the vehicle physical parameters of the target vehicle;

[0007] Acquiring real-time operating parameters of the target vehicle, and using the real-time operating parameters of the target vehicle to linearize the vehicle dynamics model to obtain a linearized vehicle dynamics model;

[0008] Discretizing the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and performing differentiation processing on the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model;

[0009] Calculating a real-time state target value of the target vehicle's steering according to the driving intention of the target driver on the target vehicle, and calculating a steady-state feedforward control amount of the target vehicle using the real-time state target value of the target vehicle's steering and the linearized vehicle dynamics model;

[0010] Calculating the feedback control amount of the target vehicle based on a linear quadratic regulator LQR using the real-time state target value of the target vehicle steering and the vehicle dynamics model after differentiation;

[0011] The cumulative sum of the steady-state feedforward control amount and the feedback control amount is used as the output control amount of the actuator corresponding to the target vehicle, and the output control amount is used to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

[0012] In an optional implementation, the vehicle physical parameters of the target vehicle include the front half wheelbase, rear half wheelbase, track width, vehicle mass, yaw moment of inertia, and front and rear wheel cornering stiffness of the target vehicle.

[0013] In an optional implementation, constructing a vehicle dynamics model using vehicle physical parameters of the target vehicle includes:

[0014] Ignoring the change in the moment arm of the longitudinal force caused by the front wheel turning angle, the vehicle dynamics model is constructed using the front half wheelbase, rear half wheelbase, track, vehicle mass, yaw moment of inertia and front and rear wheel cornering stiffness of the target vehicle.

[0015] In an optional implementation, the real-time operating parameters of the target vehicle include the vehicle yaw rate, center of mass sideslip angle and longitudinal speed of the target vehicle in the current operating state; the vehicle dynamics model is linearized by using the real-time operating parameters of the target vehicle to obtain the linearized vehicle dynamics model, including:

[0016] The vehicle dynamics model is linearized using the vehicle yaw angular velocity, center of mass sideslip angle and longitudinal velocity of the target vehicle in the current running state to obtain a linearized vehicle dynamics model.

[0017] In an optional implementation, the real-time state target value of the target vehicle's steering includes a vehicle yaw angular velocity target value and a longitudinal vehicle speed target value under a current operating state of the target vehicle.

[0018] In an optional implementation, the using the real-time state target value of the target vehicle steering and the differentiated vehicle dynamics model to calculate the feedback control amount of the target vehicle based on a linear quadratic regulator LQR includes:

[0019] The vehicle yaw rate target value and longitudinal speed target value under the current running state of the target vehicle are taken as control targets, and based on the differentiated vehicle dynamics model, LQR is used to calculate the feedback control amount of the front wheel steering angle and the left and right wheel tire forces of the target vehicle.

[0020] In an optional implementation, the calculating of the steady-state feedforward control amount of the target vehicle by using the real-time state target value of the steering of the target vehicle and the linearized vehicle dynamics model includes:

[0021] The center of mass sideslip angle of the target vehicle is set to zero, and the vehicle yaw rate target value and the longitudinal speed target value of the target vehicle in the current operating state are used as control targets. Based on the linearized vehicle dynamics model, the steady-state feedforward control amount of the target vehicle is calculated.

[0022] Corresponding to the above-mentioned coordinated control method for vehicle steering, the present application proposes a coordinated control device for vehicle steering, comprising:

[0023] A construction unit, used to obtain vehicle physical parameters of a target vehicle to be controlled, and to construct a vehicle dynamics model using the vehicle physical parameters of the target vehicle;

[0024] A linearization unit, used to obtain the real-time operating parameters of the target vehicle, and use the real-time operating parameters of the target vehicle to perform linearization processing on the vehicle dynamics model to obtain a linearized vehicle dynamics model;

[0025] A discretization unit is used to discretize the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and to perform a differentiation process on the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model;

[0026] A first calculation unit is used to calculate a real-time state target value of the steering of the target vehicle according to the driving intention of the target driver on the target vehicle, and calculate a steady-state feedforward control amount of the target vehicle by using the real-time state target value of the steering of the target vehicle and the linearized vehicle dynamics model;

[0027] A second calculation unit is used to calculate the feedback control amount of the target vehicle based on a linear quadratic regulator LQR by using the real-time state target value of the steering of the target vehicle and the vehicle dynamics model after differentiation;

[0028] A control unit is used to use the cumulative sum of the steady-state feedforward control amount and the feedback control amount as the output control amount of the actuator corresponding to the target vehicle, and use the output control amount to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

[0029] In an optional implementation, the vehicle physical parameters of the target vehicle include the front half wheelbase, rear half wheelbase, track width, vehicle mass, yaw moment of inertia, and front and rear wheel cornering stiffness of the target vehicle.

[0030] In an optional implementation, the construction unit is specifically used to:

[0031] Ignoring the change in the moment arm of the longitudinal force caused by the front wheel turning angle, the vehicle dynamics model is constructed using the front half wheelbase, rear half wheelbase, track, vehicle mass, yaw moment of inertia and front and rear wheel cornering stiffness of the target vehicle.

[0032] In an optional implementation, the real-time operating parameters of the target vehicle include the vehicle yaw rate, center of mass sideslip angle and longitudinal speed in the current operating state of the target vehicle; the linearization unit is specifically used for:

[0033] The vehicle dynamics model is linearized using the vehicle yaw angular velocity, center of mass sideslip angle and longitudinal velocity of the target vehicle in the current running state to obtain a linearized vehicle dynamics model.

[0034] In an optional implementation, the real-time state target value of the target vehicle's steering includes a vehicle yaw angular velocity target value and a longitudinal vehicle speed target value under a current operating state of the target vehicle.

[0035] In an optional implementation manner, the second computing unit is specifically configured to:

[0036] The vehicle yaw rate target value and longitudinal speed target value under the current running state of the target vehicle are taken as control targets, and based on the differentiated vehicle dynamics model, LQR is used to calculate the feedback control amount of the front wheel steering angle and the left and right wheel tire forces of the target vehicle.

[0037] In an optional implementation manner, the first computing unit is specifically configured to:

[0038] The center of mass sideslip angle of the target vehicle is set to zero, and the vehicle yaw rate target value and the longitudinal speed target value of the target vehicle in the current operating state are used as control targets. Based on the linearized vehicle dynamics model, the steady-state feedforward control amount of the target vehicle is calculated.

[0039] The embodiment of the present application also provides a coordinated control device for vehicle steering, including: a processor, a memory, and a system bus;

[0040] The processor and the memory are connected via the system bus;

[0041] The memory is used to store one or more programs, and the one or more programs include instructions, which, when executed by the processor, enable the processor to execute any one of the implementation methods of the above-mentioned vehicle steering cooperative control method.

[0042] An embodiment of the present application also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a terminal device, the terminal device executes any one of the implementation methods of the above-mentioned vehicle steering collaborative control method.

[0043] It can be seen that the embodiments of the present application have the following beneficial effects:

[0044] The embodiments of the present application provide a coordinated control method, device and equipment for vehicle steering, which first obtains vehicle physical parameters of a target vehicle to be controlled, and uses the vehicle physical parameters of the target vehicle to construct a vehicle dynamics model, then obtains real-time operating parameters of the target vehicle, and uses the real-time operating parameters of the target vehicle to linearize the vehicle dynamics model to obtain a linearized vehicle dynamics model; then discretizes the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and differentiates the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model; then, according to the driving intention of a target driver on the target vehicle, calculates the real-time state target value of the steering of the target vehicle, and uses the real-time state target value of the steering of the target vehicle and the linearized vehicle dynamics model to calculate the steady-state feedforward control amount of the target vehicle. The real-time state target value of the target vehicle's steering and the differentiated vehicle dynamics model are used to calculate the feedback control quantity of the target vehicle based on the linear quadratic regulator LQR. Finally, the cumulative sum of the steady-state feedforward control quantity and the feedback control quantity is used as the output control quantity of the actuator corresponding to the target vehicle, and the output control quantity is used to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

[0045] This achieves coordinated control of the target vehicle's steering, which not only ensures that the target driver's driving intention is followed, but also minimizes the target driver's subjective perception of the active intervention of the control function, thereby improving the steering control effect of the target vehicle and the driving experience of the target driver. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 A flowchart of a coordinated control method for vehicle steering provided in an embodiment of the present application;

[0048] Figure 2 An example diagram of the meaning of each parameter variable in the vehicle dynamics model provided in the embodiment of the present application;

[0049] Figure 3 A simulation example diagram of a coordinated control method for vehicle steering provided in an embodiment of the present application;

[0050] Figure 4 A schematic diagram of the composition of a coordinated control device for vehicle steering provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] As we all know, with the continuous advancement of high-tech technologies such as cloud computing, artificial intelligence, modern sensing, information fusion, and communication, the future development speed of vehicles will also accelerate, and people's perception and driving needs for vehicles are also gradually increasing. At present, driven by the platformization of vehicle motion domain computing control and the standardization of wire control execution system, the vehicle motion domain can coordinate the control of vehicle drive, braking and steering systems. For example, in the process of turning a car, in order to accurately realize the driving steering intention and improve the understeering / oversteering situation, it can be achieved by actively intervening the front wheel angle through the wire control steering system, or by intervening the longitudinal force through the wire control drive and wire control brake system. Therefore, how to coordinate the allocation of the control amount of the horizontal and vertical to achieve the optimal control effect is a problem that must be solved. However, the current vehicle control algorithm is basically a control method of decoupling the horizontal and vertical directions, and the stability correction strategy adopts a large number of empirical control rules and simple allocation methods, which makes it difficult to achieve the optimal control effect.

[0053] For example, when the vehicle understeers or oversteers when turning, the existing control method is to activate the VDC function, increase the braking force on one of the vehicle's wheels, and thus change the vehicle's yaw rate to improve the problem of inaccurate vehicle steering. However, this control method can only complete the vehicle's stability control by applying braking force to a single wheel of the vehicle, and during the activation of VDC, the longitudinal speed of the vehicle cannot be guaranteed, which violates the user's driving intention. In addition, this control method cannot improve the vehicle's steering performance by the technical means of collaboratively changing the front wheel angle, and may require the driver to constantly correct the steering wheel angle to ensure the correctness of the steering, which adds a burden to the driver's control of the vehicle, and also enhances his perception of VDC intervention, reducing the user's driving experience.

[0054] Based on this, the present application proposes a collaborative control method, device and equipment for vehicle steering, which can realize collaborative control of the steering of a target vehicle, not only ensuring the following of the driver's driving intention, but also minimizing the subjective perception caused by the driver's active intervention in the control function, thereby improving the steering control effect of the target vehicle and the driver's driving experience.

[0055] The coordinated control method for vehicle steering provided by the embodiment of the present application will be described in detail below with reference to the accompanying drawings. Figure 1 As shown, it shows a flow chart of an embodiment of a coordinated control method for vehicle steering provided in an embodiment of the present application. This embodiment may include the following steps:

[0056] S101: Acquire vehicle physical parameters of a target vehicle to be controlled, and construct a vehicle dynamics model using the vehicle physical parameters of the target vehicle.

[0057] In this embodiment, any vehicle that realizes the coordinated control of steering by the method of the embodiment of the present application is defined as the target vehicle to be controlled. In order to realize the coordinated control of the steering of the target vehicle, so as to improve the steering control effect of the target vehicle and the driving experience of the driver, the control scheme proposed in this application is: when the target vehicle turns, the linear quadratic regulator (Linear Quadratic Regulator, LQR) algorithm is used to solve the optimal control method to balance the front wheel angle of the target vehicle and the size of the braking / driving force of the wheels on both sides. And by actively correcting the front wheel angle of the vehicle, or applying different braking / driving force corrections on the left and right wheels, the yaw moment of the vehicle is changed, so that the requirements of the yaw angular velocity of the vehicle and the longitudinal speed of the vehicle can be met at the same time. At this time, due to the characteristics of the wire control system, the steering wheel angle will not be changed, and the travel of the brake / driving pedal will not be changed, so that the subjective perception of the driver's active intervention in the control function can be minimized while ensuring the following driving intention, thereby improving the steering control effect of the target vehicle and the driving experience of the driver.

[0058] Specifically, it is first necessary to obtain the vehicle physical parameters of the target vehicle to be controlled, and then use the vehicle physical parameters of the target vehicle to construct a vehicle dynamics model to execute the subsequent step S102.

[0059] The vehicle physical parameters of the target vehicle may include but are not limited to the front half wheelbase (defined as a here), the rear half wheelbase (defined as b here), the wheelbase (defined as t here), the vehicle mass (defined as m here), the yaw moment of inertia (defined as I here), and the z ) and the front and rear wheel cornering stiffness (here they are defined as C f ,C r ).

[0060] When constructing the vehicle dynamics model, this application takes into account that the vehicle moves on a horizontal plane, ignores the vertical degrees of freedom of the vehicle, and ignores the change in the arm of the longitudinal force caused by the front wheel turning angle. The vehicle dynamics model established using the target vehicle's front half wheelbase, rear half wheelbase, wheelbase, vehicle mass, yaw moment of inertia, and front and rear wheel cornering stiffness and other vehicle physical parameters is as follows:

[0061]

[0062] Where a is the front wheelbase; b is the rear wheelbase; t is the wheelbase; m is the vehicle mass; I z represents the yaw moment of inertia; δ represents the front wheel turning angle; Indicates the rate of change of the vehicle's yaw rate; Indicates the rate of change of the vehicle's center of mass sideslip angle; Indicates the rate of change of the vehicle's longitudinal velocity (i.e., the vehicle's longitudinal acceleration); F xfl ,F xfr ,F xrl ,F xrr Respectively represent the longitudinal forces of the left front, right front, left rear and right rear wheels of the vehicle; F yfl ,F yfr ,F yrl ,F yrr They represent the lateral forces of the left front, right front, left rear and right rear wheels of the vehicle respectively. The meaning of each variable is shown in the following examples: Figure 2 shown.

[0063] Furthermore, when it is assumed that the front wheel steering angle δ is small (such as δ is 5 degrees), it can be approximately obtained that sinδ=δ, cosδ=1. At this time, the above vehicle dynamics model can be converted into the following formula:

[0064]

[0065] Where a is the front wheelbase; b is the rear wheelbase; t is the wheelbase; m is the vehicle mass; I z represents the yaw moment of inertia; Indicates the rate of change of the vehicle's yaw rate; Indicates the rate of change of the vehicle's center of mass sideslip angle; Indicates the rate of change of the vehicle's longitudinal velocity (i.e. longitudinal acceleration); F yf Indicates the total lateral force on the front axle of the vehicle, that is, F yf =F yfl +F yfr ; F yr Indicates the total lateral force on the rear axle of the vehicle, that is, F yr =F yrl +F yrr ; F xl Indicates the total longitudinal force on the left side of the vehicle, that is, F xl =F xfl +F xrl ; F xr Indicates the total longitudinal force on the right side of the vehicle, i.e. F xr =F xfr +F xrr .

[0066] According to the existing lateral force definition

[0067]

[0068]

[0069] Where γ represents the vehicle's yaw rate; β represents the vehicle's center of mass sideslip angle; v x Indicates the longitudinal velocity of the vehicle.

[0070] The above vehicle dynamics model formula can be converted into the form of a nonlinear model as follows:

[0071]

[0072] Where x represents the state vector value of the vehicle, which can be x=[γ β v x ] T ; u represents the output control quantity of the corresponding actuator of the vehicle, and its value can be u=[δ F xl F xr ] T .

[0073] S102: Acquire real-time operating parameters of the target vehicle, and use the real-time operating parameters of the target vehicle to linearize the vehicle dynamics model to obtain a linearized vehicle dynamics model.

[0074] In this embodiment, in order to achieve coordinated control of the steering of the target vehicle to improve the steering control effect of the target vehicle and the driving experience of the driver, after constructing the vehicle dynamics model using the vehicle physical parameters of the target vehicle in step S101, the real-time operating parameters of the target vehicle can be further obtained, and the vehicle dynamics model can be linearized using the real-time operating parameters to obtain the linearized vehicle dynamics model for executing the subsequent step S103.

[0075] Among them, the real-time operating parameters of the target vehicle (using x * The yaw rate of the target vehicle in the current operating state (using γ * ), center of mass side slip angle (using β * ) and longitudinal speed (using Indicates), such as x * It can be expressed as:

[0076] Specifically, after obtaining the real-time operating parameters x of the target vehicle * After that, the current longitudinal speed of the target vehicle can be used Current yaw rate γ * 、Current vehicle center of mass sideslip angle β * , calculate the front wheel turning angle δ that satisfies the following formula * :

[0077]

[0078] The meaning of each letter is as described above and will not be repeated here.

[0079] Furthermore, at the current working point (i.e., the real-time operating parameter of the target vehicle is x * , the front wheel turning angle is δ * ), the vehicle dynamics model is linearized to obtain the linearized vehicle dynamics model. The specific processing formula is as follows:

[0080]

[0081] in, Indicates the rate of change of the real-time state vector value (i.e., real-time operating parameters) of the vehicle; the values ​​of matrix A and matrix B are as follows:

[0082]

[0083]

[0084] The meaning of each letter is as described above and will not be repeated here.

[0085] S103: discretizing the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and performing differentiation processing on the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model.

[0086] In this embodiment, after the linearized vehicle dynamics model is obtained through step S102, since the model is a continuous system model, in order to meet the actual application of the vehicle controller, the linearized vehicle dynamics model can be further discretized to obtain a discretized vehicle dynamics model, and the discretized vehicle dynamics model can be differentiated to obtain a differentiated vehicle dynamics model for executing the subsequent step S104.

[0087] Specifically, the linearized vehicle dynamics model is discretized, and the calculation formula of the discretized vehicle dynamics model is as follows:

[0088] x k+1 =A d x k +B d u k

[0089] Among them, A d and B d u k The calculation method is as follows:

[0090]

[0091]

[0092] Among them, I represents the unit matrix, and its dimension is the same as that of matrix A; k represents the kth moment; ΔT represents the discrete sampling time, and its specific value is not limited and can be set according to actual conditions and experience. For example, the value can be 5 milliseconds.

[0093] Furthermore, in order to achieve coordinated control of the target vehicle steering in the subsequent steps, the output control amount of each vehicle actuator (such as δ, F xl 、F xr For example, if the value of δ is limited from 5 degrees to 6 degrees, and then gradually changes to 7 degrees, 8 degrees, 9 degrees, and 10 degrees, instead of directly changing from 5 degrees to 10 degrees, the discretized vehicle dynamics model can be differentiated to obtain the differentiated vehicle dynamics model as shown below:

[0094] x′ k+1 =A′x′ k +B′Δu k

[0095] The calculation method of each letter is as follows:

[0096]

[0097]

[0098]

[0099] Δu k =u k -u k-1

[0100] The meaning of each letter is as described above and will not be repeated here.

[0101] S104: Calculate the real-time state target value of the target vehicle's steering according to the driving intention of the target driver on the target vehicle, and calculate the steady-state feedforward control amount of the target vehicle using the real-time state target value of the target vehicle's steering and the linearized vehicle dynamics model.

[0102] In this embodiment, in order to achieve coordinated control of the steering of the target vehicle to improve the steering control effect of the target vehicle and the driving experience of the driver, it is also necessary to obtain the driving intention of the target driver on the target vehicle. For example, the driving intention can be determined by obtaining the angle at which the target driver rotates the steering wheel or the value of the accelerator pedal, and the real-time state target value of the steering of the target vehicle is calculated according to the driving intention. The real-time state target value of the steering of the target vehicle and the linearized vehicle dynamics model obtained through step S102 are used to calculate the steady-state feedforward control amount of the target vehicle to execute the subsequent step S105.

[0103] The real-time state target value of the target vehicle steering may include but is not limited to the vehicle yaw rate target value under the current running state of the target vehicle (using γ r Indicated), longitudinal vehicle speed target value (using ), and the vehicle center of mass side slip angle target value (using β r indicates) can be set to 0, that is, β r Always equal to 0.

[0104] Specifically, an optional implementation method is to obtain the real-time state target value of the target vehicle steering, and then calculate the vehicle center of mass side slip angle target value β r Set it to be equal to 0, and use the target vehicle yaw rate γ under the current running state of the target vehicle r , Longitudinal vehicle speed target value As the control target, based on the linearized vehicle dynamics model, the steady-state feedforward control quantity of the target vehicle is calculated (using u ff The specific calculation formula is as follows:

[0105] Ar+Bu ff =0

[0106] in, And the vehicle center of mass side slip angle target value β r Set it to be always equal to 0; the meanings of other letters are still as described above and will not be repeated here.

[0107] S105: Calculate the feedback control amount of the target vehicle based on the linear quadratic regulator LQR by using the real-time state target value of the target vehicle steering and the differentiated vehicle dynamics model.

[0108] In this embodiment, in order to achieve coordinated control of the target vehicle's steering and improve the steering control effect of the target vehicle and the driver's driving experience, the vehicle yaw rate target value γ is obtained in step S104. r , Longitudinal vehicle speed target value After obtaining the real-time state target value of the target vehicle steering, the real-time state target value of the target vehicle steering and the differentiated vehicle dynamics model obtained in step S103 can be further used to calculate the feedback control amount of the target vehicle based on LQR to execute the subsequent step S106.

[0109] Specifically, an optional implementation method is to obtain the real-time state target value of the target vehicle steering and use the vehicle yaw angular velocity target value γ contained therein to obtain the real-time state target value of the target vehicle steering. r , Longitudinal vehicle speed target value As the control target, and setting the vehicle center of mass sideslip angle target value β rAfter being equal to 0, LQR is used to calculate the feedback control amount of the front wheel steering angle and the left and right wheel tire forces of the target vehicle based on the vehicle dynamics model after differentiation.

[0110] In this implementation, the penalty matrix can be set as follows:

[0111]

[0112]

[0113] The values ​​of each matrix are as follows:

[0114]

[0115]

[0116] The diagonal elements q1, q2, and q3 in Q are numbers greater than or equal to zero. The specific values ​​are not limited. The example values ​​can be 800, 800, and 50, which represent the controlled state variables γ, β, and v respectively. x The greater the value, the less tolerance there is for the error of the corresponding state variable. The diagonal elements r1, r2, r3 in R are also numbers greater than or equal to zero. The specific values ​​are not limited. The example values ​​can be 0.01, 0, 0, which respectively represent the control input variables δ, F xl ,F xr The penalty degree of the absolute value of the control input variable (i.e., the lateral front wheel steering angle of the vehicle, the total longitudinal force on the left side of the vehicle, and the total longitudinal force on the right side of the vehicle). The larger the value, the smaller the corresponding control input variable value is expected to be. The diagonal elements r1′, r2′, r3′ in R′ are also numbers greater than or equal to zero. The specific values ​​are not limited. The example values ​​can be 100, 0.1, and 0.1, which respectively represent the changes in the control input variables (i.e., the changes in the lateral front wheel steering angle of the vehicle, the total longitudinal force on the left side of the vehicle, and the total longitudinal force on the right side of the vehicle) Δδ, ΔF xl ,ΔF xr The larger the penalty value, the smaller the change of the corresponding control input variable is expected to be.

[0117] In this way, after solving the following Ricardi equation, we can get the matrix P:

[0118] A′ T P′+P′A′-P′B′R ′-1 B ′T P′+Q′=0

[0119] Therefore, the feedback gain matrix K can be calculated as follows:

[0120] K=R′ -1 B′T P′

[0121] Then calculate the real-time state target value γ of the target vehicle steering r , and β r Always equal to 0, and the vehicle's real-time status feedback The optimal feedback control increment can be calculated as follows:

[0122]

[0123] in, represents the value of the feedback control variable at the k-1th moment, and can be defined Then the total feedback control quantity at the kth moment (using The calculation formula of (expressed) is as follows:

[0124]

[0125] S106: The cumulative sum of the steady-state feedforward control amount and the feedback control amount is used as the output control amount of the actuator corresponding to the target vehicle, and the output control amount is used to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

[0126] In this embodiment, the steady-state feedforward control quantity u of the target vehicle is calculated in step S104. ff , and the feedback control amount of the target vehicle at the kth moment is calculated by step S105 After that, the two can be further accumulated to obtain the cumulative sum at the kth moment as follows:

[0127]

[0128] It is understandable that, among them, u k It can be used as the output control quantity of the actuator corresponding to the target vehicle, such as the vehicle lateral front wheel steering angle at the kth moment (i.e., δ k ), the total longitudinal force on the left side of the vehicle (i.e. F xl,k ) and the total longitudinal force on the right side of the vehicle (i.e. F xr,k ), i.e. u k =[δ k F xl,k F xr,k ] T .

[0129] Furthermore, these output control quantities of the corresponding actuators of the vehicle can be used to coordinately control the steering of the target vehicle to realize the driving intention of the target driver and control the target vehicle to reach its real-time state target value of the steering, that is, to control the yaw angular velocity of the target vehicle to reach the target value γ r, the longitudinal speed reaches the target value wait.

[0130] It should be noted that in order to verify the accuracy of the above-mentioned coordinated control method for vehicle steering, the present application also built the operating environment of the control method proposed in the present application based on the MATLAB / Simulink platform, and performed a closed-loop simulation verification based on the controlled target vehicle model provided by CarSim. The simulation results are as follows: Figure 3 As shown. Figure 3 It can be seen that the controlled target vehicle can track the target set values ​​of yaw rate and longitudinal speed very well, and when paying more attention to the tracking of yaw rate, the tracking requirement for longitudinal speed is relatively low; the smaller the vehicle's center of mass slip angle is, the better, but due to the constraints of physical variables between the center of mass slip angle and the vehicle's yaw angle and the vehicle's rear wheel center of mass slip angle, it is basically impossible to achieve complete control of zero, but its value can be within a smaller range, such as Figure 3 As shown, it is kept within a very small range (±0.01rad), which can also meet the preset actual control needs and improve the driving experience.

[0131] In this way, by executing the above steps S101-106, relying on the vehicle motion domain computing platform, the coordinated optimal control of the target vehicle during the steering process can be completed by using distributed systems such as wire control braking, wire control steering, wire control driving, and wheel hub motors, thereby improving the steering control effect of the target vehicle. In addition, the coordinated control strategy can be used to simultaneously track the driver's lateral intention (vehicle yaw rate target value) and longitudinal intention (vehicle longitudinal velocity target value), thereby improving the driver's driving experience.

[0132] In summary, the present embodiment provides a coordinated control method for vehicle steering, which first obtains vehicle physical parameters of a target vehicle to be controlled, and uses the vehicle physical parameters of the target vehicle to construct a vehicle dynamics model, then obtains real-time operating parameters of the target vehicle, and uses the real-time operating parameters of the target vehicle to linearize the vehicle dynamics model to obtain a linearized vehicle dynamics model; then discretizes the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and differentiates the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model; and then calculates the real-time state target value of the target vehicle's steering according to the driving intention of the target driver on the target vehicle, and calculates the steady-state feedforward control amount of the target vehicle using the real-time state target value of the target vehicle's steering and the linearized vehicle dynamics model. The real-time state target value of the target vehicle's steering and the differentiated vehicle dynamics model are used to calculate the feedback control quantity of the target vehicle based on the linear quadratic regulator LQR. Finally, the cumulative sum of the steady-state feedforward control quantity and the feedback control quantity is used as the output control quantity of the actuator corresponding to the target vehicle, and the output control quantity is used to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

[0133] This achieves coordinated control of the target vehicle's steering, which not only ensures that the target driver's driving intention is followed, but also minimizes the target driver's subjective perception of the active intervention of the control function, thereby improving the steering control effect of the target vehicle and the driving experience of the target driver.

[0134] See also Figure 4 As shown, the present application also provides an embodiment of a coordinated control device for vehicle steering, which may include:

[0135] A construction unit 401 is used to obtain vehicle physical parameters of a target vehicle to be controlled, and to construct a vehicle dynamics model using the vehicle physical parameters of the target vehicle;

[0136] A linearization unit 402, used to obtain the real-time operating parameters of the target vehicle, and use the real-time operating parameters of the target vehicle to linearize the vehicle dynamics model to obtain a linearized vehicle dynamics model;

[0137] The discretization unit 403 is used to discretize the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and to perform a differentiation process on the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model;

[0138] A first calculation unit 404 is used to calculate a real-time state target value of the target vehicle's steering according to the driving intention of the target driver on the target vehicle, and calculate a steady-state feedforward control amount of the target vehicle using the real-time state target value of the target vehicle's steering and the linearized vehicle dynamics model;

[0139] A second calculation unit 405 is used to calculate the feedback control amount of the target vehicle based on a linear quadratic regulator LQR by using the real-time state target value of the target vehicle steering and the vehicle dynamics model after differentiation;

[0140] A control unit is used to use the cumulative sum of the steady-state feedforward control amount and the feedback control amount as the output control amount of the actuator corresponding to the target vehicle, and use the output control amount to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

[0141] In some possible implementations of the present application, the vehicle physical parameters of the target vehicle include the front half wheelbase, rear half wheelbase, track width, vehicle mass, yaw moment of inertia and front and rear wheel cornering stiffness of the target vehicle.

[0142] In some possible implementations of the present application, the construction unit 401 is specifically used to:

[0143] Ignoring the change in the moment arm of the longitudinal force caused by the front wheel turning angle, the vehicle dynamics model is constructed using the front half wheelbase, rear half wheelbase, track, vehicle mass, yaw moment of inertia and front and rear wheel cornering stiffness of the target vehicle.

[0144] In some possible implementations of the present application, the real-time operating parameters of the target vehicle include the vehicle yaw rate, center of mass sideslip angle and longitudinal speed of the target vehicle in the current operating state; the linearization unit 402 is specifically used for:

[0145] The vehicle dynamics model is linearized using the vehicle yaw angular velocity, center of mass sideslip angle and longitudinal velocity of the target vehicle in the current running state to obtain a linearized vehicle dynamics model.

[0146] In some possible implementations of the present application, the real-time state target value of the target vehicle's steering includes a vehicle yaw angular velocity target value and a longitudinal vehicle speed target value under the current operating state of the target vehicle.

[0147] In some possible implementations of the present application, the second calculating unit 405 is specifically configured to:

[0148] The vehicle yaw rate target value and longitudinal speed target value under the current running state of the target vehicle are taken as control targets, and based on the differentiated vehicle dynamics model, LQR is used to calculate the feedback control amount of the front wheel steering angle and the left and right wheel tire forces of the target vehicle.

[0149] In some possible implementations of the present application, the first calculating unit 404 is specifically configured to:

[0150] The center of mass sideslip angle of the target vehicle is set to zero, and the vehicle yaw rate target value and the longitudinal speed target value of the target vehicle in the current operating state are used as control targets. Based on the linearized vehicle dynamics model, the steady-state feedforward control amount of the target vehicle is calculated.

[0151] It can be seen from the above embodiments that the collaborative control device for vehicle steering provided in the embodiments of the present application first obtains the vehicle physical parameters of the target vehicle to be controlled, and uses the vehicle physical parameters of the target vehicle to construct a vehicle dynamics model, then obtains the real-time operating parameters of the target vehicle, and uses the real-time operating parameters of the target vehicle to linearize the vehicle dynamics model to obtain a linearized vehicle dynamics model; then discretizes the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and differentiates the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model; and then calculates the real-time state target value of the target vehicle's steering according to the driving intention of the target driver on the target vehicle, and uses the real-time state target value of the target vehicle's steering and the linearized vehicle dynamics model to calculate the steady-state feedforward control amount of the target vehicle. The real-time state target value of the target vehicle's steering and the differentiated vehicle dynamics model are used to calculate the feedback control quantity of the target vehicle based on the linear quadratic regulator LQR. Finally, the cumulative sum of the steady-state feedforward control quantity and the feedback control quantity is used as the output control quantity of the actuator corresponding to the target vehicle, and the output control quantity is used to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

[0152] This achieves coordinated control of the target vehicle's steering, which not only ensures that the target driver's driving intention is followed, but also minimizes the target driver's subjective perception of the active intervention of the control function, thereby improving the steering control effect of the target vehicle and the driving experience of the target driver.

[0153] Furthermore, an embodiment of the present application also provides a coordinated control device for vehicle steering, comprising: a processor, a memory, and a system bus;

[0154] The processor and the memory are connected via the system bus;

[0155] The memory is used to store one or more programs, and the one or more programs include instructions, which, when executed by the processor, enable the processor to execute any implementation method of the above-mentioned vehicle steering cooperative control method.

[0156] Furthermore, an embodiment of the present application also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a terminal device, the terminal device executes any one of the implementation methods of the above-mentioned vehicle steering collaborative control method.

[0157] It can be known from the description of the above implementation mode that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., including several instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0158] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0159] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0160] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coordinated control method for vehicle steering, characterized in that: include: Acquiring vehicle physical parameters of a target vehicle to be controlled, and constructing a vehicle dynamics model using the vehicle physical parameters of the target vehicle; Acquiring real-time operating parameters of the target vehicle, and using the real-time operating parameters of the target vehicle to linearize the vehicle dynamics model to obtain a linearized vehicle dynamics model; Discretizing the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and performing differentiation processing on the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model; Calculating a real-time state target value of the target vehicle's steering according to the driving intention of the target driver on the target vehicle, and calculating a steady-state feedforward control amount of the target vehicle using the real-time state target value of the target vehicle's steering and the linearized vehicle dynamics model; Calculating the feedback control amount of the target vehicle based on a linear quadratic regulator LQR using the real-time state target value of the target vehicle steering and the vehicle dynamics model after differentiation; The cumulative sum of the steady-state feedforward control amount and the feedback control amount is used as the output control amount of the actuator corresponding to the target vehicle, and the output control amount is used to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

2. The method according to claim 1, characterized in that The vehicle physical parameters of the target vehicle include the front half wheelbase, rear half wheelbase, track width, vehicle mass, yaw moment of inertia, and front and rear wheel cornering stiffness of the target vehicle.

3. The method according to claim 2, characterized in that The method of constructing a vehicle dynamics model using vehicle physical parameters of the target vehicle includes: Ignoring the change in the moment arm of the longitudinal force caused by the front wheel turning angle, the vehicle dynamics model is constructed using the front half wheelbase, rear half wheelbase, track, vehicle mass, yaw moment of inertia and front and rear wheel cornering stiffness of the target vehicle.

4. The method according to claim 1, characterized in that: The real-time operating parameters of the target vehicle include the vehicle yaw rate, center of mass sideslip angle and longitudinal speed of the target vehicle in the current operating state; the vehicle dynamics model is linearized by using the real-time operating parameters of the target vehicle to obtain the linearized vehicle dynamics model, including: The vehicle dynamics model is linearized using the vehicle yaw angular velocity, center of mass sideslip angle and longitudinal velocity of the target vehicle in the current running state to obtain a linearized vehicle dynamics model.

5. The method according to claim 1, characterized in that The real-time state target value of the target vehicle steering includes a vehicle yaw angular velocity target value and a longitudinal vehicle speed target value under the current running state of the target vehicle.

6. The method according to claim 5, characterized in that The method of calculating the feedback control amount of the target vehicle based on a linear quadratic regulator LQR by using the real-time state target value of the steering of the target vehicle and the vehicle dynamics model after differentiation includes: The vehicle yaw rate target value and longitudinal speed target value under the current running state of the target vehicle are taken as control targets, and based on the differentiated vehicle dynamics model, LQR is used to calculate the feedback control amount of the front wheel steering angle and the left and right wheel tire forces of the target vehicle.

7. The method according to claim 5, characterized in that The method of calculating the steady-state feedforward control amount of the target vehicle by using the real-time state target value of the steering of the target vehicle and the linearized vehicle dynamics model comprises: The center of mass sideslip angle of the target vehicle is set to zero, and the vehicle yaw rate target value and the longitudinal speed target value of the target vehicle in the current operating state are used as control targets. Based on the linearized vehicle dynamics model, the steady-state feedforward control amount of the target vehicle is calculated.

8. A coordinated control device for vehicle steering, characterized in that: include: A construction unit, used to obtain vehicle physical parameters of a target vehicle to be controlled, and to construct a vehicle dynamics model using the vehicle physical parameters of the target vehicle; A linearization unit, used to obtain the real-time operating parameters of the target vehicle, and use the real-time operating parameters of the target vehicle to perform linearization processing on the vehicle dynamics model to obtain a linearized vehicle dynamics model; A discretization unit is used to discretize the linearized vehicle dynamics model to obtain a discretized vehicle dynamics model; and to perform a differentiation process on the discretized vehicle dynamics model to obtain a differentiated vehicle dynamics model; A first calculation unit is used to calculate a real-time state target value of the steering of the target vehicle according to the driving intention of the target driver on the target vehicle, and calculate a steady-state feedforward control amount of the target vehicle by using the real-time state target value of the steering of the target vehicle and the linearized vehicle dynamics model; A second calculation unit is used to calculate the feedback control amount of the target vehicle based on a linear quadratic regulator LQR by using the real-time state target value of the steering of the target vehicle and the vehicle dynamics model after differentiation; A control unit is used to use the cumulative sum of the steady-state feedforward control amount and the feedback control amount as the output control amount of the actuator corresponding to the target vehicle, and use the output control amount to coordinately control the steering of the target vehicle to achieve the driving intention of the target driver.

9. A coordinated control device for vehicle steering, characterized in that: include: Processor, memory, system bus; The processor and the memory are connected via the system bus; The memory is used to store one or more programs, wherein the one or more programs include instructions, and when the instructions are executed by the processor, the processor executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a terminal device, the terminal device executes the method according to any one of claims 1 to 7.

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