Unmanned vehicle speed regulation control method and system based on sideslip warning

Abstract

The present invention discloses a speed regulation control method and system for an unmanned vehicle based on side slip warning, the method comprising: using the combined force of the vehicle centrifugal force and the tire lateral force as the influencing factor affecting the vehicle side slip, constructing an unmanned vehicle side slip angle prediction model to calculate the unmanned vehicle side slip angle in the prediction time domain; designing an unmanned vehicle side slip warning optimization objective function based on the side slip angle prediction model; solving the optimization objective function to obtain the optimal longitudinal speed, using the optimal longitudinal speed as the actual control input, and realizing the unmanned vehicle speed regulation control. The scheme of the present invention can solve the technical problem that the existing speed regulation control method is too conservative, resulting in a low average longitudinal speed of the vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of motion control of unmanned vehicles, and in particular to a speed regulation control method and system of an unmanned vehicle based on sideslip warning. Background Art

[0002] The motion control of unmanned vehicles can usually be divided into longitudinal control and lateral control. Longitudinal control is longitudinal speed control, and lateral control is path tracking control. In existing unmanned vehicle motion control systems, longitudinal speed control and path tracking control are usually performed separately. Control technology that actively adjusts the longitudinal speed to reduce sideslip and thus improves the accuracy of path tracking control is relatively rare.

[0003] In the existing control technology of reducing sideslip by actively adjusting the longitudinal speed (CN110085057A, CN114023080A), a maximum speed limit is usually set to prevent sideslip. The maximum speed limit is usually calculated by the curve radius, gravity acceleration, ground adhesion coefficient and road inclination. The core idea is to make the centrifugal force of the vehicle smaller than the ground adhesion. However, since sideslip is caused by the lateral speed formed by the integral of the lateral acceleration caused by the combined force of the centrifugal force and the lateral force of the tire, if the centrifugal force is greater than the ground adhesion for a short time, it will not cause sideslip.

[0004] In summary, the prior art usually adopts a lower longitudinal speed as the maximum vehicle speed limit to prevent skidding, but there is a problem that the technical solution is too conservative, resulting in a lower average longitudinal speed of the vehicle. Summary of the invention

[0005] The present invention provides a speed regulation control method and system for an unmanned vehicle based on side slip warning, so as to solve the technical problem that the prior art is too conservative, resulting in a low average longitudinal speed of the vehicle.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] On the one hand, the present invention provides a method for adjusting and controlling the speed of an unmanned vehicle based on a sideslip warning, the method for adjusting and controlling the speed of an unmanned vehicle based on a sideslip warning comprising:

[0008] Taking the combined force of vehicle centrifugal force and tire lateral force as the influencing factor of vehicle sideslip, a side slip angle prediction model of unmanned vehicle is constructed to calculate the side slip angle of unmanned vehicle in the prediction time domain;

[0009] Based on the sideslip angle prediction model, an optimization objective function for the sideslip warning of unmanned vehicles is designed;

[0010] The optimization objective function is solved to obtain an optimal longitudinal speed, and the optimal longitudinal speed is used as an actual control input to achieve speed regulation control of the unmanned vehicle.

[0011] Furthermore, the method of using the combined force of the vehicle centrifugal force and the tire lateral force as the influencing factor affecting the vehicle sideslip to construct an unmanned vehicle side slip angle prediction model to calculate the unmanned vehicle side slip angle in the prediction time domain includes:

[0012] Construct a two-DOF single-track model for the vehicle:

[0013]

[0014] Among them, v x is the longitudinal velocity, v y is the lateral velocity, ω is the yaw angular velocity, F yf 、F yr are the lateral forces of the front and rear axle wheels, δ is the equivalent turning angle of the front wheel of the vehicle, L f , L r are the distances between the front and rear axles and the center of mass of the vehicle, m is the mass of the vehicle, I z is the moment of inertia of the vehicle around the vertical direction;

[0015] The front and rear axle tire slip angles are calculated using the longitudinal velocity, lateral velocity and yaw rate using the formula:

[0016]

[0017] Combining equations (1) and (2), considering that the equivalent steering angle of the vehicle's front wheels is provided by the path tracking controller and is a known quantity, the model input only includes the longitudinal velocity, and the following abstract model is obtained:

[0018] x=f(x,u) (3)

[0019] in:

[0020]

[0021] According to the principle of nonlinear model predictive control, the model is discretized to obtain the state quantity in the prediction time domain: x(t+i|t), i=1,2,…,N p ; The calculation formula of the sideslip angle in the prediction time domain is obtained as follows:

[0022]

[0023] Among them, t represents the time, i represents the i-th predicted state, and N p Represents the prediction time domain.

[0024] Furthermore, based on the sideslip angle prediction model, the optimization objective function of the unmanned vehicle sideslip warning is designed, including:

[0025] Design the following penalty items:

[0026]

[0027] Among them, k is the proportionality coefficient, α lim is the sideslip angle limit;

[0028] Based on the penalty term, the following unmanned vehicle sideslip warning optimization objective function is designed:

[0029]

[0030] Among them, Q1 and Q2 represent weight coefficients, N c Indicates the number of control steps.

[0031] Furthermore, solving the optimization objective function to obtain an optimal longitudinal speed, and using the optimal longitudinal speed as an actual control input to implement speed regulation control of the unmanned vehicle includes:

[0032] The optimization objective function is solved to obtain a longitudinal velocity sequence, and the first value in the longitudinal velocity sequence obtained is used as an actual control input to implement speed regulation control of the unmanned vehicle.

[0033] On the other hand, the present invention also provides an unmanned vehicle speed adjustment control system based on sideslip warning, the unmanned vehicle speed adjustment control system based on sideslip warning comprises:

[0034] The unmanned vehicle side slip angle prediction model building module is used to build an unmanned vehicle side slip angle prediction model using the combined force of the vehicle centrifugal force and the tire lateral force as the influencing factor affecting the vehicle side slip, so as to calculate the unmanned vehicle side slip angle in the prediction time domain;

[0035] An unmanned vehicle sideslip warning optimization objective function design module is used to design an unmanned vehicle sideslip warning optimization objective function based on the sideslip angle prediction model;

[0036] The solution control module is used to solve the optimization objective function to obtain the optimal longitudinal speed, and use the optimal longitudinal speed as the actual control input to achieve speed regulation control of the unmanned vehicle.

[0037] Furthermore, the unmanned vehicle sideslip angle prediction model building module is specifically used for:

[0038] Construct a two-DOF single-track model for the vehicle:

[0039]

[0040] Among them, v x is the longitudinal velocity, v y is the lateral velocity, ω is the yaw angular velocity, F yf 、F yr are the lateral forces of the front and rear axle wheels, δ is the equivalent turning angle of the front wheel of the vehicle, L f , L r are the distances between the front and rear axles and the center of mass of the vehicle, m is the mass of the vehicle, I z is the moment of inertia of the vehicle around the vertical direction;

[0041] The front and rear axle tire slip angles are calculated using the longitudinal velocity, lateral velocity and yaw rate using the formula:

[0042]

[0043] Combining equations (1) and (2), considering that the equivalent steering angle of the vehicle's front wheels is provided by the path tracking controller and is a known quantity, the model input only includes the longitudinal velocity, and the following abstract model is obtained:

[0044] x=f(x,u) (3)

[0045] in:

[0046]

[0047] According to the principle of nonlinear model predictive control, the model is discretized to obtain the state quantity in the prediction time domain: x(t+i|t), i=1,2,…,N p ; The calculation formula of the sideslip angle in the prediction time domain is obtained as follows:

[0048]

[0049] Among them, t represents the time, i represents the i-th predicted state, and N p Represents the prediction time domain.

[0050] Furthermore, the unmanned vehicle sideslip warning optimization objective function design module is specifically used for:

[0051] Design the following penalty items:

[0052]

[0053] Among them, k is the proportionality coefficient, α lim is the sideslip angle limit;

[0054] Based on the penalty term, the following unmanned vehicle sideslip warning optimization objective function is designed:

[0055]

[0056] Among them, Q1 and Q2 represent weight coefficients, N c Indicates the number of control steps.

[0057] Furthermore, the solution control module is specifically used for:

[0058] The optimization objective function is solved to obtain a longitudinal velocity sequence, and the first value in the longitudinal velocity sequence obtained is used as an actual control input to implement speed regulation control of the unmanned vehicle.

[0059] On the other hand, the present invention further provides an electronic device, comprising a processor and a memory; wherein the memory stores at least one instruction, and the instruction is loaded and executed by the processor to implement the above method.

[0060] In yet another aspect, the present invention further provides a computer-readable storage medium, wherein the storage medium stores at least one instruction, and the instruction is loaded and executed by a processor to implement the above method.

[0061] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0062] The unmanned vehicle speed regulation control method based on sideslip warning of the present invention adopts the idea of ​​predictive control, firstly establishes an unmanned vehicle sideslip angle prediction model, and then designs a sideslip warning optimization objective function, so as to obtain a faster longitudinal speed that can reduce the sideslip of the unmanned vehicle, thereby solving the problem that the existing speed regulation control method is too conservative, resulting in a low average longitudinal speed of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0064] Figure 1 It is a schematic diagram of the execution flow of the unmanned vehicle speed regulation control method based on sideslip warning provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0065] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0066] First embodiment

[0067] This embodiment provides a method for controlling the speed of an unmanned vehicle based on side slip warning, which can be implemented by an electronic device. Figure 1 As shown, the following steps are included:

[0068] S1, taking the combined force of the vehicle centrifugal force and the tire lateral force as the influencing factor of the vehicle sideslip, constructing an unmanned vehicle sideslip angle prediction model to calculate the unmanned vehicle sideslip angle in the prediction time domain;

[0069] S2, designing an optimization objective function for the sideslip warning of the unmanned vehicle based on the sideslip angle prediction model;

[0070] S3, solving the optimization objective function to obtain an optimal longitudinal speed, and using the optimal longitudinal speed as an actual control input to implement speed regulation control of the unmanned vehicle.

[0071] Specifically, in this embodiment, the implementation process of the above S1 is as follows:

[0072] First, build a two-degree-of-freedom single-track model for the vehicle:

[0073]

[0074] Among them, v x is the longitudinal velocity, v y is the lateral velocity, ω is the yaw angular velocity, F yf 、F yr are the lateral forces of the front and rear axle wheels, respectively. They can be calculated using tire models such as the magic formula, with the sideslip angle as input. δ is the equivalent turning angle of the front wheel of the vehicle, and L f , L r are the distances between the front and rear axles and the center of mass of the vehicle, m is the mass of the vehicle, I z is the moment of inertia of the vehicle around the vertical direction;

[0075] The side slip angles of the front and rear axle tires can be calculated using variables such as longitudinal velocity, lateral velocity, and yaw rate:

[0076]

[0077] Combining the above models, considering that the equivalent steering angle of the front wheels of the vehicle is provided by the path tracking controller and is a known quantity, the model input only includes the longitudinal velocity, and the following abstract model can be obtained:

[0078] x=f(x,u) (3)

[0079] in:

[0080]

[0081] According to the principle of nonlinear model predictive control, the model can be discretized to obtain the state quantity in the prediction time domain: x(t+i|t), i=1,2,…,N p ; From this, the calculation formula for the sideslip angle in the prediction time domain can be obtained as:

[0082]

[0083] Among them, t represents the time, i represents the i-th predicted state, and N p Represents the prediction time domain.

[0084] Furthermore, the design method of the optimization objective function of the side slip warning of the unmanned vehicle is as follows:

[0085] Considering that a certain slip angle will be generated during normal driving of the vehicle, and the vehicle will skid only when the slip angle exceeds the adhesion limit, the following penalty items can be designed:

[0086]

[0087] Among them, k is the proportionality coefficient, α lim is the sideslip angle limit;

[0088] Based on the penalty term, the following unmanned vehicle sideslip warning optimization objective function is designed:

[0089]

[0090] Among them, Q1 and Q2 represent weight coefficients, N c Indicates the number of control steps.

[0091] Furthermore, the implementation process of the above S3 is as follows:

[0092] The optimization objective function is solved to obtain a longitudinal velocity sequence, and the first value in the longitudinal velocity sequence obtained is used as an actual control input to implement speed regulation control of the unmanned vehicle.

[0093] In summary, this embodiment provides a speed regulation control method for an unmanned vehicle based on sideslip warning. The speed regulation control method for an unmanned vehicle based on sideslip warning adopts the idea of ​​predictive control. First, a sideslip angle prediction model of an unmanned vehicle is established, and then a sideslip warning optimization objective function is designed to obtain a faster longitudinal speed that can reduce the sideslip of the unmanned vehicle, thereby solving the problem that the existing speed regulation control method is too conservative, resulting in a low average longitudinal speed of the vehicle.

[0094] Second embodiment

[0095] This embodiment provides an unmanned vehicle speed adjustment control system based on sideslip warning, and the unmanned vehicle speed adjustment control system based on sideslip warning includes the following modules:

[0096] The unmanned vehicle side slip angle prediction model building module is used to build an unmanned vehicle side slip angle prediction model using the combined force of the vehicle centrifugal force and the tire lateral force as the influencing factor affecting the vehicle side slip, so as to calculate the unmanned vehicle side slip angle in the prediction time domain;

[0097] An unmanned vehicle sideslip warning optimization objective function design module is used to design an unmanned vehicle sideslip warning optimization objective function based on the sideslip angle prediction model;

[0098] The solution control module is used to solve the optimization objective function to obtain the optimal longitudinal speed, and use the optimal longitudinal speed as the actual control input to achieve speed regulation control of the unmanned vehicle.

[0099] The unmanned vehicle speed regulation and control system based on sideslip warning of this embodiment corresponds to the unmanned vehicle speed regulation and control method based on sideslip warning of the above-mentioned first embodiment; wherein, the functions implemented by each functional module in the unmanned vehicle speed regulation and control system based on sideslip warning of this embodiment correspond one-to-one to each process step in the unmanned vehicle speed regulation and control method based on sideslip warning of the above-mentioned first embodiment; therefore, they will not be repeated here.

[0100] Third embodiment

[0101] This embodiment provides an electronic device, which includes a processor and a memory; wherein the memory stores at least one instruction, and the instruction is loaded and executed by the processor to implement the method of the first embodiment.

[0102] The electronic device may have relatively large differences due to different configurations or performances, and may include one or more processors (central processing units, CPU) and one or more memories, wherein the memory stores at least one instruction, and the instruction is loaded by the processor to execute the above method.

[0103] Fourth embodiment

[0104] This embodiment provides a computer-readable storage medium, which stores at least one instruction, and the instruction is loaded and executed by a processor to implement the method of the first embodiment. The computer-readable storage medium may be a ROM, a random access memory, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc. The instructions stored therein may be loaded by a processor in a terminal to execute the method.

[0105] In addition, it should be noted that the present invention can be provided as a method, an apparatus or a computer program product. Therefore, the embodiments of the present invention can take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, the embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code.

[0106] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0107] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device, so that a series of operation steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable terminal device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0108] It should also be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0109] Finally, it should be noted that the above is a preferred embodiment of the present invention. It should be pointed out that although the preferred embodiment of the present invention has been described, for those skilled in the art, once the basic creative concept of the present invention is known, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the embodiments of the present invention.

Claims

1. A speed regulation control method for an unmanned vehicle based on side slip warning, characterized in that: The unmanned vehicle speed adjustment control method based on sideslip warning includes: Taking the combined force of vehicle centrifugal force and tire lateral force as the influencing factor of vehicle sideslip, a side slip angle prediction model of unmanned vehicle is constructed to calculate the side slip angle of unmanned vehicle in the prediction time domain; Based on the sideslip angle prediction model, an optimization objective function for the sideslip warning of unmanned vehicles is designed; Solving the optimization objective function to obtain an optimal longitudinal speed, and using the optimal longitudinal speed as an actual control input to implement speed regulation control of the unmanned vehicle; Based on the sideslip angle prediction model, an optimization objective function for the sideslip warning of unmanned vehicles is designed, including: Design the following penalty items: Among them, k is the proportionality coefficient, α lim is the side slip angle limit; N p represents the prediction time domain; Based on the penalty term, the following unmanned vehicle sideslip warning optimization objective function is designed: Among them, Q1 and Q2 represent weight coefficients, N c represents the number of control steps; v x is the longitudinal velocity; t represents the time, and i represents the i-th predicted state.

2. The unmanned vehicle speed adjustment control method based on sideslip warning according to claim 1, characterized in that: The method of using the combined force of the vehicle centrifugal force and the tire lateral force as the influencing factor affecting the vehicle sideslip to construct an unmanned vehicle side slip angle prediction model to calculate the unmanned vehicle side slip angle in the prediction time domain includes: Construct a two-degree-of-freedom single-track model of the vehicle: Among them, v x is the longitudinal velocity, v y is the lateral velocity, ω is the yaw angular velocity, F yf 、F yr are the lateral forces of the front and rear axle wheels, δ is the equivalent turning angle of the front wheel of the vehicle, L f , L r are the distances between the front and rear axles and the center of mass of the vehicle, m is the mass of the vehicle, I z is the moment of inertia of the vehicle around the vertical direction; The front and rear axle tire slip angles are calculated using the longitudinal velocity, lateral velocity and yaw rate using the formula: Combining equations (1) and (2), considering that the equivalent steering angle of the vehicle's front wheels is provided by the path tracking controller and is a known quantity, the model input only includes the longitudinal velocity, and the following abstract model is obtained: x=f(x,u) (3) in: According to the principle of nonlinear model predictive control, the model is discretized to obtain the state quantity in the prediction time domain: x(t+i|t), i=1,2,…,N p ; The calculation formula of the sideslip angle in the prediction time domain is obtained as follows: Among them, t represents the time, i represents the i-th predicted state, and N p Represents the prediction time domain.

3. The unmanned vehicle speed adjustment control method based on sideslip warning according to claim 1 is characterized in that: The step of solving the optimization objective function to obtain an optimal longitudinal speed, and using the optimal longitudinal speed as an actual control input to implement speed regulation control of the unmanned vehicle includes: The optimization objective function is solved to obtain a longitudinal velocity sequence, and the first value in the longitudinal velocity sequence obtained is used as an actual control input to implement speed regulation control of the unmanned vehicle.

4. A speed regulation and control system for an unmanned vehicle based on side slip warning, characterized in that: The unmanned vehicle speed adjustment control system based on sideslip warning includes: The unmanned vehicle side slip angle prediction model building module is used to build an unmanned vehicle side slip angle prediction model using the combined force of the vehicle centrifugal force and the tire lateral force as the influencing factor affecting the vehicle side slip, so as to calculate the unmanned vehicle side slip angle in the prediction time domain; An unmanned vehicle sideslip warning optimization objective function design module is used to design an unmanned vehicle sideslip warning optimization objective function based on the sideslip angle prediction model; A solution control module is used to solve the optimization objective function to obtain an optimal longitudinal speed, and use the optimal longitudinal speed as an actual control input to achieve speed regulation control of the unmanned vehicle; The unmanned vehicle sideslip warning optimization objective function design module is specifically used for: Design the following penalty items: Among them, k is the proportionality coefficient, α lim is the side slip angle limit; N p represents the prediction time domain; Based on the penalty term, the following unmanned vehicle sideslip warning optimization objective function is designed: Among them, Q1 and Q2 represent weight coefficients, N c represents the number of control steps; v x is the longitudinal velocity; t represents the time, and i represents the i-th predicted state.

5. The unmanned vehicle speed adjustment control system based on sideslip warning as claimed in claim 4, characterized in that: The unmanned vehicle sideslip angle prediction model building module is specifically used for: Construct a two-degree-of-freedom single-track model of the vehicle: Among them, v x is the longitudinal velocity, v y is the lateral velocity, ω is the yaw angular velocity, F yf 、F yr are the lateral forces of the front and rear axle wheels, δ is the equivalent turning angle of the front wheel of the vehicle, L f , L r are the distances between the front and rear axles and the center of mass of the vehicle, m is the mass of the vehicle, I z is the moment of inertia of the vehicle around the vertical direction; The front and rear axle tire slip angles are calculated using the longitudinal velocity, lateral velocity and yaw rate using the formula: Combining equations (1) and (2), considering that the equivalent steering angle of the vehicle's front wheels is provided by the path tracking controller and is a known quantity, the model input only includes the longitudinal velocity, and the following abstract model is obtained: x=f(x,u) (3) in: According to the principle of nonlinear model predictive control, the model is discretized to obtain the state quantity in the prediction time domain: x(t+i|t), i=1,2,…,N p ; The calculation formula of the sideslip angle in the prediction time domain is obtained as follows: Among them, t represents the time, i represents the i-th predicted state, and N p Represents the prediction time domain.

6. The unmanned vehicle speed adjustment control system based on sideslip warning as claimed in claim 4, characterized in that: The solution control module is specifically used for: The optimization objective function is solved to obtain a longitudinal velocity sequence, and the first value in the longitudinal velocity sequence obtained is used as an actual control input to implement speed regulation control of the unmanned vehicle.

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