A vehicle queue sliding mode control method, device, system and storage medium

Abstract

The present invention discloses a vehicle queue sliding mode control method and device, system, and storage medium, including: obtaining the space state of the vehicle queue according to the position error, speed error and the longitudinal nonlinear dynamic model of the vehicle when there is external interference between vehicles; obtaining the state switching function according to the position error and speed error between vehicles; obtaining the queue state control law according to the space state of the vehicle queue state and the state switching function; obtaining the exponential approach law according to the state switching function; obtaining the sliding mode control law according to the exponential approach law, the state switching function and the space state of the vehicle queue during sliding mode control; obtaining the fleet control law according to the sliding mode control law and the queue state control law. The technical solution of the present invention is adopted to realize the disturbance suppression and smoothness control of the vehicle queue, and at the same time ensure the overall stability of the vehicle queue when the communication of the vehicle queue is interrupted, and ensure that the stability of the vehicle queue is restored to stability in a short time.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle control, and in particular relates to a vehicle queue sliding mode control method and device, system, and storage medium. Background Art

[0002] In recent years, connected autonomous vehicles have attracted more and more attention. V2V communication technology allows real-time transmission of status information such as position, acceleration and speed. Subsequent vehicles can use on-board sensors to receive and interpret this information, thereby achieving cooperative control. However, in complex traffic environments and severe weather conditions, unforeseen electrical or electromagnetic interference may interfere with communication equipment or signal transmission, or even interrupt vehicle queue communication. As scholars have conducted in-depth research on this issue, sliding mode control has emerged as a powerful solution, providing strong resilience and rapid response characteristics in complex and uncertain environments. By introducing the sliding surface, precise control of the system is achieved, the overall control effect is improved, and the impact of interference on the communication system is reduced. Y. Zhu et al. designed a joint distributed adaptive sliding mode controller to avoid the disturbance effect of adjacent vehicles. G. Feng et al. used sliding mode control theory to handle different disturbances and minimize their convergence, thereby proposing a new coordinated control scheme to achieve queue stability. At present, commonly used sliding mode control methods include constant speed reaching law, quasi-sliding mode reaching law and exponential reaching law. Many scholars have shown that the constant speed reaching law exhibits a slower control speed and obvious acceleration oscillation, resulting in poor sliding mode stability. On the other hand, the quasi-sliding mode control law has better stability and faster control speed. However, its acceleration and smoothness of control input are not as good as the exponential reaching law. The exponential reaching law allows the sliding mode to reach the desired state in a non-finite time, and the transfer function eventually converges to zero. This method provides faster control speed and more stable control input.

[0003] However, another important component of vehicle platooning is the vehicle spacing strategy, which has an important impact on the control of the platoon. The spacing strategy determines the rationality of the preset vehicle distance, which affects traffic safety and road capacity. At present, the commonly used spacing strategies include constant spacing strategy and constant time spacing strategy. In the case of vehicle communication interruption, the connected vehicle will transition to a non-connected vehicle, hindering information reception and transmission, making the vehicle platoon unstable and possibly leading to rear-end collisions. In order to solve these problems, scholars from home and abroad have conducted extensive research. H. Chehardoli et al. introduced a constant spacing dynamic strategy based on the constant spacing strategy and proposed a new decentralized robust adaptive consensus protocol. Ge Guo et al. proposed an adaptive sliding mode platoon control scheme to adjust the vehicle spacing through a constant spacing strategy. Based on the constant time spacing strategy, Y. Bian et al. studied the multi-leader tracking strategy using vehicle-to-vehicle (V2V) communication technology and introduced a constant time spacing strategy to ensure interference attenuation capability. The constant spacing strategy (CS) can only achieve string stability on spacing error when there is at least one leader-follower communication topology. In addition, since vehicles using the constant spacing strategy are difficult to cope with the changing following conditions, the application of pure constant spacing strategy vehicle platoons in practice has been greatly affected. The constant time strategy (CTH) can improve the stability of the vehicle platoon to a certain extent, but the pure constant time strategy (CTH) lacks flexibility under rapidly changing speed conditions. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a vehicle queue sliding mode control method and device, system, and storage medium to achieve disturbance suppression and smoothness control of the vehicle queue, while ensuring the overall stability of the vehicle queue when the vehicle queue communication is interrupted, and ensuring that the stability of the vehicle queue is restored in a short time.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A vehicle platoon sliding mode control method, comprising:

[0007] Step S1, obtaining the position error and speed error between vehicles according to the expected distance between vehicles;

[0008] Step S2, obtaining a longitudinal nonlinear dynamic model of the vehicle when there is external interference according to the position error and speed error between the vehicles;

[0009] Step S3, obtaining the spatial state of the vehicle queue according to the position error, speed error and the longitudinal nonlinear dynamic model of the vehicle when there is external interference between the vehicles;

[0010] Step S4, obtaining a state switching function according to the position error and speed error between vehicles;

[0011] Step S5, obtaining a queue state control law according to the vehicle queue state space state and the state switching function;

[0012] Step S6, obtaining an exponential approach law according to the state switching function;

[0013] Step S7, obtaining a sliding mode control law according to the exponential reaching law, the state switching function and the spatial state of the vehicle queue during sliding mode control;

[0014] Step S8: Obtain a convoy control law based on the sliding mode control law and the queue state control law.

[0015] As a preferred method, the queue state control law for:

[0016]

[0017] Among them, q1 is the coefficient of vehicle position error, q2 is the coefficient of vehicle speed error, g i is the communication delay time, a i-1 and v i-1 is the acceleration and speed of vehicle i-1, v i is the speed of vehicle i, c i is the drag coefficient, f is the vehicle drag coefficient, M i is the vehicle mass, ω i (t) is the concentrated interference of the external environment on the vehicle platoon communication, a i-1 (t) is the acceleration of vehicle i-1.

[0018] As a preferred method, the sliding mode control law for:

[0019]

[0020] Among them, S i It is the state switching function.

[0021] The present invention also provides a vehicle queue sliding mode control device, comprising:

[0022] A first calculation module is used to obtain a position error and a speed error between vehicles according to an expected distance between the vehicles;

[0023] The second calculation module is used to obtain a longitudinal nonlinear dynamic model of the vehicle when there is external interference based on the position error and speed error between the vehicles;

[0024] The third calculation module is used to obtain the spatial state of the vehicle queue according to the position error, speed error and longitudinal nonlinear dynamic model of the vehicle when there is external interference between the vehicles;

[0025] A fourth calculation module, used for obtaining a state switching function according to a position error and a speed error between vehicles;

[0026] A fifth calculation module, used for obtaining a queue state control law according to the state space state of the vehicle queue and the state switching function;

[0027] A sixth calculation module, used for obtaining an exponential approach law according to the state switching function;

[0028] a seventh calculation module, for obtaining a sliding mode control law according to an exponential reaching law, a state switching function and a space state of a vehicle queue during sliding mode control;

[0029] The eighth calculation module is used to obtain the fleet control law according to the sliding mode control law and the queue state control law.

[0030] As a preferred method, the queue state control law u i n (t) is:

[0031]

[0032] Among them, q1 is the coefficient of vehicle position error, q2 is the coefficient of vehicle speed error, g i is the communication delay time, a i-1 and v i-1 is the acceleration and speed of vehicle i-1, v i is the speed of vehicle i, c i is the drag coefficient, f is the vehicle drag coefficient, M i is the vehicle mass, ω i (t) is the concentrated interference of the external environment on the vehicle platoon communication, a i-1 (t) is the acceleration of vehicle i-1.

[0033] As a preferred method, the sliding mode control law for:

[0034]

[0035] Among them, S i It is the state switching function.

[0036] The present invention also provides a vehicle queue sliding mode control system, comprising: a memory and a processor, wherein the memory stores a computer program executed by the processor, and the computer program executes a vehicle queue sliding mode control method when executed by the processor.

[0037] The present invention also provides a storage medium, on which a computer program is stored, and the computer program executes the vehicle queue sliding mode control method when running.

[0038] The present invention obtains the space state of the vehicle queue according to the position error, speed error and the longitudinal nonlinear dynamic model of the vehicle when there is external interference between vehicles; obtains the state switching function according to the position error and speed error between vehicles; obtains the queue state control law according to the space state of the vehicle queue state and the state switching function; obtains the exponential approach law according to the state switching function; obtains the sliding mode control law according to the exponential approach law, the state switching function and the space state of the vehicle queue under sliding mode control; obtains the fleet control law according to the sliding mode control law and the queue state control law. The technical solution of the present invention is adopted to realize the disturbance suppression and smoothness control of the vehicle queue, and at the same time ensure the overall stability of the vehicle queue when the communication of the vehicle queue is interrupted, and ensure that the stability of the vehicle queue is restored in a short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention 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 only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0040] Figure 1 It is a flow chart of the vehicle platoon sliding mode control method based on the exponential reaching law of the present invention;

[0041] Figure 2 A schematic diagram of a fleet of vehicles according to the present invention;

[0042] Figure 3 It is a schematic diagram of switching the spacing strategy of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Embodiment 1:

[0046] like Figure 1 As shown, an embodiment of the present invention provides a vehicle queue sliding mode control method, comprising:

[0047] Step S1, obtaining the position error and speed error between vehicles according to the expected distance between vehicles;

[0048] Step S2, obtaining a longitudinal nonlinear dynamic model of the vehicle when there is external interference according to the position error and speed error between the vehicles;

[0049] Step S3, obtaining the spatial state of the vehicle queue according to the position error, speed error and the longitudinal nonlinear dynamic model of the vehicle when there is external interference between the vehicles;

[0050] Step S4, obtaining a state switching function according to the position error and speed error between vehicles;

[0051] Step S5, obtaining a queue state control law according to the vehicle queue state space state and the state switching function;

[0052] Step S6, obtaining an exponential approach law according to the state switching function;

[0053] Step S7, obtaining a sliding mode control law according to the exponential reaching law, the state switching function and the spatial state of the vehicle queue during sliding mode control;

[0054] Step S8: Obtain a convoy control law based on the sliding mode control law and the queue state control law.

[0055] As an implementation method of the embodiment of the present invention, Figure 2 and 3 As shown, in step 1,

[0056] In the constant time-to-head strategy (CTH), the expected distance between vehicles is as follows:

[0057] d i =hv i-1 (t)+D

[0058] Among them, d i is the expected distance between vehicle i (following vehicle) and vehicle i-1 (leading vehicle); D is the ideal intermediate vehicle distance between the front bumper of vehicle i and the front bumper of vehicle i-1 at rest; h is the headway; v i-1 (t) is the speed of vehicle i-1.

[0059] The constant spacing strategy (CS) is introduced to design the headway into a selection matrix, which is expressed as follows:

[0060] h=[h CS ,h CTH ] T

[0061] Among them, h CS represents the headway time of vehicles using the constant spacing strategy; hCTH Represents the headway time of vehicles using a constant headway strategy.

[0062] When h = 0, d i =D; when h≠0, d i Determined using a constant time interval strategy.

[0063] The position error and speed error between vehicles are:

[0064] Δp i (t) = p i (t)-p i-1 (t)+d i

[0065] Δv i (t) = v i (t)-v i-1 (t)

[0066] Among them, Δp i (t), Δv i (t) are the position error and speed error of vehicle i, respectively, i (t), v i (t) are the position and speed of vehicle i, p i-1 (t), v i-1 (t) are the position and speed of vehicle i-1 respectively.

[0067] As an implementation of the embodiment of the present invention, in step S2, the longitudinal nonlinear dynamic model of the vehicle when there is external interference:

[0068]

[0069] in, is the differential of the position and velocity of vehicle i, is the queue state control law, c i is the drag coefficient, f is the vehicle drag coefficient, M i is the vehicle mass, ω i (t) is the concentrated interference of the external environment on the vehicle platoon communication, a i-1 (t) is the acceleration of vehicle i-1.

[0070] As an implementation of an embodiment of the present invention, in step S3, the vehicle queue space state is:

[0071]

[0072] in, is the differential of the position error of the fleet at time t; is the differential of the velocity error at time t.

[0073] As an implementation method of the present invention, in step S4, a state switching function is designed based on the idea of ​​sliding mode control, and the state switching function S i for:

[0074] S i =q1Δp i (t)+q2Δv i (t)q1>0,q2>0

[0075] Among them, q1 is the coefficient of vehicle position error, and q2 is the coefficient of vehicle speed error.

[0076] As an implementation of the embodiment of the present invention, in step S5,

[0077] Let S i =0, the state switching function is:

[0078] q1Δp i (t)+q2Δv i (t) = 0

[0079] And take the derivative of the left and right sides of the state switching function equation to get:

[0080]

[0081] Combined with the formula of the vehicle queue space state, we get

[0082]

[0083] Queue State Control Law for:

[0084]

[0085] As an implementation method of the present invention, in step S6, the exponential approach law for:

[0086]

[0087] Among them, λ is the convergence coefficient.

[0088] As an implementation of the embodiment of the present invention, in step S7, the vehicle queue space state during sliding mode control is:

[0089]

[0090] By taking the derivative of the state switching function, we can get:

[0091]

[0092] Combining the exponential reaching law and the formula for the spatial state of the vehicle queue under sliding mode control, we get

[0093]

[0094] Sliding Mode Control Law

[0095]

[0096] As an implementation of the present invention, in step S8, the fleet control law u i (t) is:

[0097]

[0098] The embodiment of the present invention adopts spacing strategy switching, queue state control law and sliding mode control law. The spacing strategy switching is a spacing strategy selection. In the case of communication interruption, the spacing strategy can be dynamically adjusted, and a dynamic control problem is obtained in the fleet error function, so that the control target can be flexibly switched according to the actual communication situation of the fleet, thereby improving the stability of the fleet; the queue state control law introduces an interference function according to the actual interference of the fleet communication, and controls the actual state of the fleet through the state space state of the vehicle queue, the longitudinal nonlinear dynamic model of the vehicle when there is external interference, and the speed error under communication interference; the sliding mode control law introduces an exponential approach law, combines the space state of the vehicle queue during sliding mode control and the state switching function, and performs sliding mode control on the trajectory when the communication is abnormal. The embodiment of the present invention adopts a spacing strategy flexible switching framework, thereby improving the flexibility and stability of the fleet in the face of interference; the sliding mode control can allow the sliding mode to reach the desired state in a non-finite time, so that the fleet control can be faster and more stable; effectively solve the communication interference caused by complex environment, prevent the deterioration of vehicle queue performance, and ensure that the stability of the vehicle queue is restored in a short time.

[0099] Embodiment 2:

[0100] The embodiment of the present invention further provides a vehicle queue sliding mode control device, comprising:

[0101] A first calculation module is used to obtain a position error and a speed error between vehicles according to an expected distance between the vehicles;

[0102] The second calculation module is used to obtain a longitudinal nonlinear dynamic model of the vehicle when there is external interference based on the position error and speed error between the vehicles;

[0103] The third calculation module is used to obtain the spatial state of the vehicle queue according to the position error, speed error and longitudinal nonlinear dynamic model of the vehicle when there is external interference between the vehicles;

[0104] A fourth calculation module, used for obtaining a state switching function according to a position error and a speed error between vehicles;

[0105] A fifth calculation module, used for obtaining a queue state control law according to the state space state of the vehicle queue and the state switching function;

[0106] A sixth calculation module, used for obtaining an exponential approach law according to the state switching function;

[0107] a seventh calculation module, for obtaining a sliding mode control law according to an exponential reaching law, a state switching function and a space state of a vehicle queue during sliding mode control;

[0108] The eighth calculation module is used to obtain the fleet control law according to the sliding mode control law and the queue state control law.

[0109] As an implementation method of the embodiment of the present invention, the queue state control law u i n (t) is:

[0110]

[0111] Among them, q1 is the coefficient of vehicle position error, q2 is the coefficient of vehicle speed error, g i is the communication delay time, a i-1 and v i-1 is the acceleration and speed of vehicle i-1, v i is the speed of vehicle i, c i is the drag coefficient, f is the vehicle drag coefficient, M i is the vehicle mass, ω i (t) is the concentrated interference of the external environment on the vehicle platoon communication, a i-1 (t) is the acceleration of vehicle i-1.

[0112] As an implementation method of the present invention, the sliding mode control law for:

[0113]

[0114] Among them, S i It is the state switching function.

[0115] Embodiment 3:

[0116] The present invention also provides a vehicle queue sliding mode control system, comprising: a memory and a processor, wherein the memory stores a computer program executed by the processor, and the computer program executes a vehicle queue sliding mode control method when executed by the processor.

[0117] Embodiment 4:

[0118] The present invention also provides a storage medium, on which a computer program is stored, and the computer program executes the vehicle queue sliding mode control method when running.

[0119] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A vehicle platoon sliding mode control method, characterized in that: include: Step S1, obtaining the position error and speed error between vehicles according to the expected distance between vehicles; Step S2, obtaining a longitudinal nonlinear dynamic model of the vehicle when there is external interference according to the position error and speed error between the vehicles; Step S3, obtaining the spatial state of the vehicle queue according to the position error, speed error and the longitudinal nonlinear dynamic model of the vehicle when there is external interference between the vehicles; Step S4, obtaining a state switching function according to the position error and speed error between vehicles; Step S5, obtaining a queue state control law according to the vehicle queue state space state and the state switching function; Step S6, obtaining an exponential approach law according to the state switching function; Step S7, obtaining a sliding mode control law according to the exponential reaching law, the state switching function and the spatial state of the vehicle queue during sliding mode control; Step S8, obtaining a convoy control law according to the sliding mode control law and the convoy state control law; In step S2, the longitudinal nonlinear dynamic model of the vehicle in the presence of external disturbances is: in, is the differential of the position and velocity of vehicle i, is the queue state control law, c i is the drag coefficient, f is the vehicle drag coefficient, M i is the vehicle mass, ω i (t) is the concentrated interference of the external environment on the vehicle platoon communication, a i-1 (t) is the acceleration of vehicle i-1, Δv i (t) are the speed errors of vehicle i, v i (t) are the speeds of vehicle i; In step S3, the vehicle queue space state is: in, is the differential of the position error of the fleet at time t; is the differential of the velocity error at time t; In step S4, a state switching function is designed based on the idea of ​​sliding mode control. The state switching function S i for: S i =q1Δp i (t)+q2Δv i (t)q1>0,q2>0 Among them, q1 is the coefficient of vehicle position error, q2 is the coefficient of vehicle speed error; In step S5, Let S i =0, the state switching function is: q1Δp i (t)+q2Δv i (t)=0 And take the derivative of the left and right sides of the state switching function equation to get: Combined with the formula of the vehicle queue space state, we get Queue State Control Law for: In step S6, the exponential approach law S i for: Among them, λ is the convergence coefficient; In step S7, the spatial state of the vehicle queue during sliding mode control is: By taking the derivative of the state switching function, we can get: Combining the exponential reaching law and the formula for the spatial state of the vehicle queue under sliding mode control, we get Sliding Mode Control Law In step S8, the fleet control law u i (t) is:

2. A vehicle platoon sliding mode control device for implementing the vehicle platoon sliding mode control method according to claim 1, characterized in that: include: A first calculation module is used to obtain a position error and a speed error between vehicles according to an expected distance between the vehicles; The second calculation module is used to obtain a longitudinal nonlinear dynamic model of the vehicle when there is external interference based on the position error and speed error between the vehicles; The third calculation module is used to obtain the spatial state of the vehicle queue according to the position error, speed error and longitudinal nonlinear dynamic model of the vehicle when there is external interference between the vehicles; A fourth calculation module, used for obtaining a state switching function according to a position error and a speed error between vehicles; A fifth calculation module, used for obtaining a queue state control law according to the state space state of the vehicle queue and the state switching function; A sixth calculation module, used for obtaining an exponential approach law according to the state switching function; a seventh calculation module, for obtaining a sliding mode control law according to an exponential reaching law, a state switching function and a space state of a vehicle queue during sliding mode control; The eighth calculation module is used to obtain the fleet control law according to the sliding mode control law and the queue state control law.

3. A vehicle platoon sliding mode control system, comprising: A memory and a processor, wherein the memory stores a computer program executed by the processor, and when the computer program is executed by the processor, the vehicle queue sliding mode control method according to claim 1 is executed.

4. A storage medium having a computer program stored thereon, wherein the computer program executes the vehicle platoon sliding mode control method according to claim 1 when running.

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