A Distributed Finite-Time Adaptive Fault-Tolerant Control Method and System for Vehicle Queues

Abstract

The present invention relates to a distributed finite-time adaptive fault-tolerant control method and system based on a vehicle queue, comprising: constructing a vehicle longitudinal kinematic equation to obtain a vehicle queue consistency error dynamic equation; designing a sliding surface based on the vehicle queue consistency error, and calculating the sliding surface approach law; setting an adaptive parameter estimation law based on the vehicle team collaborative braking consistency error equation and the error sliding surface, estimating the vehicle fault degree online based on the optimal parameter adaptive gain, and obtaining an online vehicle fault estimation value according to different vehicle fault degrees; combining the sliding surface approach law, the vehicle queue consistency error dynamic equation and the online vehicle fault estimation value to obtain a queue distributed finite-time adaptive fault-tolerant controller to achieve fault-tolerant control of the fleet in the event of a fault. The present invention achieves fleet fault-tolerant control by designing a finite-time active fault-tolerant control strategy based on online fault estimation.

Description

Technical Field

[0001] The present invention relates to a distributed finite-time adaptive fault-tolerant control method and system based on a vehicle queue, and relates to the technical field of vehicle team collaborative control. Background Art

[0002] With the increase in the popularity of vehicles, road traffic conditions have deteriorated sharply. At present, the traffic environment faces problems such as air pollution, traffic congestion and long travel time. Vehicle platooning is an effective way to relieve traffic pressure, improve traffic efficiency and reduce pollutant emissions. Vehicle platoons are connected through vehicle-to-vehicle mobile communication equipment (V2V). Vehicles connected through the network share necessary information such as speed and position with each other to achieve the goal of coordinated movement of vehicles according to a preset strategy. In the current research on vehicle platooning, most of the work assumes that the vehicles are operating under normal conditions, and does not consider how the vehicle platoon can maintain consistency or degrade operation after a failure. The vehicle braking process is the most dangerous process and the process where failures are most likely to occur.

[0003] In the technology for fault-tolerant control of vehicle platoons, the prior art proposes a heterogeneous fleet fault-tolerant control method based on a variable time spacing strategy, which introduces a neural network to fit the vehicle fault function and designs an adaptive sliding mode control law to maintain vehicle synchronous braking. However, this technology fits the fault function through a neural network. Since a single-layer network cannot completely fit any nonlinear term, it must have a fitting error, which means that it cannot obtain the exact value of the fault, but only processes the fault into a system nonlinear term, and designs a distributed robust controller to compensate for the performance degradation caused by the fault. This will result in a lack of fault information, and the vehicle itself cannot clearly know the severity of the fault at this time.

[0004] Therefore, the failure of the fleet braking system puts higher requirements on the design of distributed fault-tolerant controllers. When a vehicle power system fails, how to balance the consistency of the fleet status, the smoothness of the single vehicle braking, and the fleet fault-tolerant transition time and other performance indicators is an urgent problem to be solved. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a distributed finite-time adaptive fault-tolerant control method, system, device and medium based on vehicle queues, which can estimate the degree of brake system failure online and provide more accurate fault information, so as to achieve state synchronization within a limited time when a failure occurs in the fleet and realize collaborative braking tasks.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a distributed finite-time adaptive fault-tolerant control method based on a vehicle queue, comprising:

[0008] Construct the longitudinal kinematic equation of the vehicle and obtain the dynamic equation of the vehicle platoon consistency error;

[0009] Design the sliding surface and sliding surface reaching law based on the vehicle platoon consistency error;

[0010] Based on the platoon cooperative braking consistency error equation and error sliding surface, an adaptive parameter estimation law is set, and the vehicle fault degree is estimated online based on the optimal parameter adaptive gain, and the online vehicle fault estimation value is obtained according to the different fault degrees of the vehicle;

[0011] By combining the sliding surface reaching law, the vehicle platoon consistency error dynamics equation and the online vehicle fault estimation value, a distributed finite-time adaptive fault-tolerant controller for the platoon is obtained to achieve fault-tolerant control of the platoon when a fault occurs.

[0012] Furthermore, the longitudinal kinematic equation of the i-th vehicle in the platoon cooperative braking is:

[0013]

[0014] In the formula, m i is the mass of the i-th vehicle, v i is the speed of the ith vehicle, θ i Indicates the degree of vehicle brake system failure, u i is the braking force input of the i-th vehicle, ρ is the air density, C A is the air resistance coefficient, A i is the frontal area of ​​the vehicle, g is the acceleration due to gravity, and f is the rolling damping coefficient.

[0015] Furthermore, based on the longitudinal kinematic equation of the vehicle, the braking safety distance constraint is introduced, and according to the vehicle-to-vehicle communication topology, the vehicle platoon consistency error dynamic equation is obtained, including:

[0016]

[0017] In the formula, Represents the derivative of position and speed synchronization error, l ij and b i It is related to the topology of the fleet communication. i = 0 indicates complete failure. f(t) is a function of vehicle wind resistance, rolling resistance, and nonlinear disturbance of the road surface. is the derivative of the velocity of the jth vehicle, u0 is the braking deceleration input of the leading vehicle, and u i is the braking deceleration input of the i-th vehicle and n is the number of vehicles following in the queue.

[0018] Furthermore, a sliding surface based on the vehicle queue consistency error and a sliding surface reaching law are designed, including:

[0019] The sliding surface s based on the vehicle queue consistency error is:

[0020] s=e i2 +k1e i1 +k2|e i1 | γ sgn(e i1 )

[0021] The reaching law of the sliding surface is:

[0022]

[0023] In the formula, e i1 , e i2 They represent the vehicle position synchronization error and speed synchronization error respectively, k1, k2, k3, k4 are the adjustable gains of the controller, all of which are real numbers greater than zero, and α, γ∈[0,1) are power exponential terms.

[0024] Furthermore, the queue distributed finite-time adaptive fault-tolerant controller is designed as follows:

[0025]

[0026] Among them, M i is the generalized mass parameter of the vehicle, variable ε i is the disturbance error of the following vehicle i, and the parameter is the online adaptive estimate of the actual fault severity θ.

[0027] Furthermore, based on the platoon cooperative braking consistency error equation and the error sliding surface, an adaptive parameter estimation law is set, the vehicle fault degree is estimated online based on the optimal parameter adaptive gain, and the online vehicle fault estimation value is obtained according to the different fault degrees of the vehicle, including:

[0028] Based on the platoon cooperative braking consistency error equation and error sliding surface, the adaptive parameter estimation law is set:

[0029]

[0030] In the formula, P and Q are intermediate variables, H is the combined error variable of variables P and Q and the online estimated value of the fault degree θ, r is the integral variable, and l(t) is the dynamic gain coefficient, which is used to adjust the filtering effect of variables P and Q, and its lower limit is l L , the upper limit is l U , tanh(·) is the hyperbolic tangent function;

[0031] An integral quadratic cost function with a discount factor is designed. By solving the minimum cost function, the optimal parameter adaptive gain is obtained to improve the online estimation response performance of the braking system fault degree.

[0032] Furthermore, an integral quadratic cost function with a discount factor is designed, and the optimal parameter adaptive gain is obtained by solving the minimum cost function, including:

[0033] Design an integral quadratic cost function with a discount factor:

[0034]

[0035] In the formula, the operator exp(·) is the exponential operator, ν is the integral variable, R0 is the quadratic coefficient, whose value is greater than 0, and η is the normalization coefficient, whose value is η 2 =1+||P 2 ||;

[0036] By solving the optimal integral quadratic cost function with discount factor, the optimal parameter adaptive gain is obtained, which satisfies the following dynamic equation:

[0037]

[0038] By minimizing the above integral cost function to obtain the optimal parameter adaptive gain, the fault parameter adaptive law can be optimized online to obtain the optimal parameter estimation dynamic response performance.

[0039] In a second aspect, the present invention further provides a distributed finite-time adaptive fault-tolerant control system based on a vehicle queue, the system comprising:

[0040] A first processing unit is configured to construct a longitudinal kinematic equation of the vehicle and obtain a vehicle platoon consistency error dynamic equation;

[0041] The second processing unit is configured to design a sliding surface based on the vehicle queue consistency error and calculate a sliding surface reaching law;

[0042] The third processing unit is configured to set an adaptive parameter estimation law based on the fleet cooperative braking consistency error equation and the error sliding surface, estimate the vehicle fault degree online based on the optimal parameter adaptive gain, and obtain an online vehicle fault estimation value according to different fault degrees of the vehicle;

[0043] The fourth processing unit is configured to combine the sliding surface reaching law, the vehicle queue consistency error dynamic equation and the online vehicle fault estimation value to obtain a queue distributed finite time adaptive fault-tolerant controller to achieve fault-tolerant control of the fleet when a fault occurs.

[0044] In a third aspect, the present invention provides an electronic device, which includes at least a processor and a memory, wherein a computer program is stored in the memory, and when the processor runs the computer program, it is executed to implement any one of the methods.

[0045] In a fourth aspect, the present invention provides a computer storage medium having computer-readable instructions stored thereon, and the computer-readable instructions can be executed by a processor to implement any one of the methods.

[0046] The present invention adopts the above technical solution, and has the following characteristics:

[0047] 1. The finite-time adaptive fault-tolerant control method for a vehicle platoon under cooperative braking conditions when a brake system failure occurs is proposed in the present invention. By designing a finite-time active fault-tolerant control strategy based on online fault estimation, the platoon fault-tolerant control is realized. This not only improves the safety of platoon cooperative braking, but also improves the robustness of the vehicle platoon to brake system failures. While providing fault-tolerant control, it provides information on the precise value of the degree of system failure, effectively reducing the occurrence of accidents.

[0048] 2. The present invention uses an integral quadratic cost function with a discount factor to optimize the parameter adaptive law. The online fault parameter adaptive law estimates the degree of fault of the vehicle braking system online through the vehicle longitudinal kinematic equation. The integral quadratic function is the optimization cost function. By solving the minimum value of the integral quadratic function, the optimal parameter adaptive gain is obtained to improve the adaptive response performance.

[0049] 3. The finite-time adaptive sliding mode fault-tolerant controller proposed in the present invention introduces a finite-time sliding surface and realizes state synchronization and coordinated braking tasks within a finite time when a fault occurs based on the consistency error equation.

[0050] 4. The present invention estimates the degree of vehicle failure online through an adaptive law and combines a distributed finite-time sliding mode controller to ensure the synchronization and consistency of multiple following vehicles during vehicle cooperative control.

[0051] In summary, the distributed finite-time adaptive fault-tolerant control of the present invention can not only compensate for the nonlinearity caused by faults during the coordinated braking process of vehicle queues, but also estimate the degree of brake system faults online and provide more accurate fault information. The present invention is not targeted at special vehicle models and special working conditions, has high practicality, and all expressions are analytical solutions with low computational cost, and has broad prospects for application in real vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings:

[0053] Figure 1 This is a flow chart of a distributed finite-time adaptive fault-tolerant control method for a vehicle queue according to an embodiment of the present invention;

[0054] Figure 2 A schematic diagram of coordinated braking of a vehicle queue according to an embodiment of the present invention;

[0055] Figure 3 The figure is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0056] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0057] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside", "outside", "inner side", "outer side", "below", "above", etc. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0058] The present invention provides a method, system, device and medium for distributed finite-time adaptive fault-tolerant control based on vehicle queues. The method includes: constructing a longitudinal kinematic equation of the vehicle to obtain a dynamic equation of the consistency error of the vehicle queue; designing a sliding surface and a sliding surface approaching law based on the consistency error of the vehicle queue; setting an adaptive parameter estimation law based on the consistency error equation of the coordinated braking of the fleet and the error sliding surface, estimating the degree of vehicle fault online based on the optimal parameter adaptive gain, and obtaining an online vehicle fault estimation value according to different degrees of vehicle fault; combining the sliding surface approaching law, the dynamic equation of the consistency error of the vehicle queue and the online vehicle fault estimation value to obtain a distributed finite-time adaptive fault-tolerant controller for the queue, and realizing fault-tolerant control of the fleet in the event of a fault. Therefore, the present invention realizes fleet fault-tolerant control by designing a finite-time active fault-tolerant control strategy based on online fault estimation.

[0059] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0060] like Figure 1 As shown, the distributed finite-time adaptive fault-tolerant control method based on vehicle queues provided in this embodiment constructs a consistency error equation by combining the vehicle state equation with the vehicle-to-vehicle communication topology, designs an active fault-tolerant controller based on the consistency error equation, and completes the queue collaborative fault-tolerant control. The specific implementation steps are as follows:

[0061] S1. Construct the longitudinal kinematic equation of the vehicle and obtain the dynamic equation of the vehicle queue consistency error.

[0062] S11. Constructing the longitudinal kinematic equations of the vehicle

[0063] The kinematic equation of the i-th vehicle in the platoon cooperative braking can be expressed as:

[0064]

[0065] In the formula, m i is the mass of the ith vehicle, v i is the speed of the ith vehicle, θ i Indicates the degree of vehicle brake system failure, u i is the braking force input of the i-th vehicle, ρ is the air density, C A is the air resistance coefficient, A i is the frontal area of ​​the vehicle, g is the acceleration due to gravity, and f is the rolling damping coefficient.

[0066] S12. Based on the longitudinal kinematic equation of the vehicle, a braking safety distance constraint is introduced, and according to the vehicle-to-vehicle communication topology, the vehicle queue consistency error dynamics equation is obtained.

[0067] Specifically, the vehicle dynamics equation of the i-th vehicle can be expressed as:

[0068]

[0069] In the formula, e i1 , e i2 They represent the vehicle position synchronization error and speed synchronization error, ΔP ij is the safe braking distance between vehicle i and vehicle j, ΔP i0 The distance constraint between vehicle i and the leading vehicle, l ij and b i It is related to the communication topology of the convoy. v0 is the speed of the leading vehicle, v j represents the speed of the jth vehicle, x i represents the position of the i-th vehicle, x j represents the position of the jth vehicle, and x represents the position of the leading vehicle.

[0070] Derivative the above equation and substitute the longitudinal kinematics equation of the vehicle into the derivative result to obtain the dynamics equation of vehicle platoon consistency error, as follows:

[0071]

[0072] In the formula, when θ i = 0 indicates complete failure. f(t) is a function of vehicle wind resistance, rolling resistance, and nonlinear disturbance of the road surface. is the derivative of the velocity of the jth vehicle, u0 is the braking deceleration input of the leading vehicle, It represents the derivative of the position and speed synchronization error, and n is the number of vehicles following the queue.

[0073] S2. Design of sliding surface and sliding surface reaching law based on vehicle platoon consistency error

[0074] The sliding surface s based on the vehicle queue consistency error is:

[0075] s=e i2 +k1e i1 +k2|e i1 | γ sgn(e i1 )

[0076] The reaching law of the sliding surface is:

[0077]

[0078] Where k1, k2, k3, k4 are the adjustable gains of the controller, all of which are real numbers greater than zero, and α, γ∈[0,1) are power exponential terms.

[0079] S3. Based on the fleet collaborative braking consistency error equation and the error sliding surface, an adaptive parameter estimation law is set, and the vehicle fault degree is estimated online based on the optimal parameter adaptive gain, and the online vehicle fault estimation value is obtained according to the different fault degrees of the vehicle.

[0080] S31. Based on the fleet cooperative braking consistency error equation, this embodiment designs the following parameter adaptive law:

[0081]

[0082] In the formula, P and Q are intermediate variables, H is a variable, P, Q and the combined error variable of the online estimated value of the fault degree θ, Γ is the system adaptive gain, and its size is closely related to the performance of the adaptive parameter estimation law. It is worth noting that the variable H contains the error information of the fault parameter θ estimation, and the adaptive law designed for it can ensure that the online estimated value approaches the true value. Parameter η 2 =1+||P T P|| 2 is the regularization coefficient, s is the sliding mode control quantity, α∈[0,1) is the power exponential term, κ1 is the gain coefficient, l(t) is the forgetting factor function, and its parameter l U , l L are the upper and lower limits of l(t), and the parameter is a sensitivity factor, which indicates the sensitivity of the forgetting factor function to parameter estimation errors. is the online estimation value of the actuator fault degree θ, x2 is the vehicle speed information, x 2f , G f , F f The expression is:

[0083]

[0084] In the formula, x 2f , G f , F f They are the variables obtained after filtering of x2, G, and F, and the parameter k>0 is an adjustable parameter;

[0085] S32. Design an integral quadratic cost function with a discount factor, obtain the optimal parameter adaptive gain by solving the minimum cost function, optimize the fault parameter estimation performance, and improve the transient response performance of online estimation of vehicle fault degree.

[0086] Specifically, if the vehicle has not failed, the value of the adaptive parameter θ will remain at 1. When designing a fault-tolerant controller, in order to ensure that the controller automatically makes adaptive changes according to the vehicle fault, a parameter adaptive law about the degree of fault is designed according to the longitudinal kinematic equation of the single vehicle. Since the adaptive law introduces parameter estimation error, it can converge to the true value of the parameter and provide true value information of the degree of fault online. At the same time, in order to optimize the response performance of parameter estimation and obtain the optimal adaptive gain, this embodiment designs an integral cost function with a discount factor, which includes but is not limited to the real-time parameter estimation error and the initial error of parameter estimation. By solving the minimum cost function, the dynamic gain of the optimal parameter estimation of the above adaptive law can be obtained, thereby improving the transient performance of system parameter estimation.

[0087] In order to improve the online estimation response performance of the brake system fault degree θ and obtain the optimal parameter adaptive gain, the present embodiment designs the following integral quadratic cost function with a discount factor:

[0088]

[0089] Wherein, the operator exp(·) is the exponential operator, ν is the integral variable, and R0 is the coefficient of the quadratic form, whose value is greater than.

[0090] By solving the optimal integral quadratic cost function with discount factor, the optimal parameter adaptive gain can be derived, which satisfies the following dynamic equation:

[0091]

[0092] By minimizing the above integral cost function to obtain the optimal parameter adaptive gain, the fault parameter adaptive law can be optimized online to obtain the optimal parameter estimation dynamic response performance.

[0093] S4. Combining the sliding surface reaching law, the vehicle queue consistency error dynamics equation and the online vehicle fault estimation value, a queue distributed finite-time adaptive fault-tolerant controller is obtained to achieve fault-tolerant control of the fleet in the event of a fault.

[0094] Specifically, according to the above results, the queue distributed finite-time adaptive fault-tolerant controller can be designed as:

[0095]

[0096] Where k1, k2, k3, k4 are the adjustable gains of the controller, all of which are real numbers greater than zero. α,γ∈[0,1) are power terms, and the parameter M i Defined as the generalized mass parameter of the vehicle, the variable ε i is the disturbance error of following vehicle i.

[0097] The above fault-tolerant controller is installed in the on-board controller of each following vehicle. Through the adaptive law of parameter θ, the fault degree of the vehicle is estimated and fitted online, which can ensure the synchronization performance of the vehicle platoon under fault conditions. Figure 2 The design of the vehicle platoon cooperative braking scenario is shown in Figure 2. The typical platoon cooperative control scenario is the braking scenario, which includes a leading vehicle and N following vehicles. N,N-1 , ΔP N-1,N-2 ... represents a preset braking safety distance between two vehicles. Without loss of generality, this embodiment adopts a non-time-varying braking safety distance strategy.

[0098] u N ,u N-1 ...represents the control input of each following vehicle, that is, the total braking force required by each following vehicle.

[0099] S N,N-1 , S N-1,N-2 ...represents the distance tracking error between two adjacent vehicles.

[0100] Through the fault-tolerant control strategy of this embodiment for the control of the fault occurrence scenario, the fleet can complete the fault-tolerant control task within a limited time, ensuring that the vehicle queue can still maintain a consistent state and stop at the desired location smoothly and quickly in the critical scenario of a fault.

[0101] Embodiment 2: The above-mentioned embodiment 1 provides a distributed finite-time adaptive fault-tolerant control method based on a vehicle queue. Correspondingly, this embodiment provides a distributed finite-time adaptive fault-tolerant control system based on a vehicle queue. The system provided in this embodiment can implement the distributed finite-time adaptive fault-tolerant control method based on a vehicle queue of embodiment 1, and the system can be implemented by software, hardware, or a combination of software and hardware. For the convenience of description, the present embodiment is described in various units according to their functions. Of course, the functions of each unit can be implemented in the same or multiple software and / or hardware during implementation. For example, the system may include integrated or separate functional modules or functional units to perform the corresponding steps in each method of embodiment 1. Since the system of this embodiment is basically similar to the method embodiment, the description process of this embodiment is relatively simple. For relevant parts, please refer to the partial description of embodiment 1. The embodiment of the distributed finite-time adaptive fault-tolerant control system based on a vehicle queue provided by the present invention is only illustrative.

[0102] The distributed finite-time adaptive fault-tolerant control system based on vehicle queues provided in this embodiment includes:

[0103] A first processing unit is configured to construct a longitudinal kinematic equation of the vehicle and obtain a vehicle platoon consistency error dynamic equation;

[0104] The second processing unit is configured to design a sliding surface based on the vehicle queue consistency error and a sliding surface reaching law;

[0105] The third processing unit is configured to set an adaptive parameter estimation law based on the fleet cooperative braking consistency error equation and the error sliding surface, estimate the vehicle fault degree online based on the optimal parameter adaptive gain, and obtain an online vehicle fault estimation value according to different fault degrees of the vehicle;

[0106] The fourth processing unit is configured to combine the sliding surface reaching law, the vehicle queue consistency error dynamic equation and the online vehicle fault estimation value to obtain a queue distributed finite time adaptive fault-tolerant controller to achieve fault-tolerant control of the fleet when a fault occurs.

[0107] Furthermore, the longitudinal kinematic equation of the i-th vehicle in the platoon cooperative braking is configured as:

[0108]

[0109] Furthermore, based on the longitudinal kinematic equation of the vehicle, the braking safety distance constraint is introduced, and according to the vehicle-to-vehicle communication topology, the vehicle platoon consistency error dynamics equation is obtained:

[0110]

[0111] Furthermore, a sliding surface based on the vehicle queue consistency error and a sliding surface reaching law are designed, including:

[0112] Based on the vehicle queue consistency error sliding surface s:

[0113] s=e i2 +k1e i1 +k2|e i1 | γ sgn(e i1 )

[0114] The reaching law of the sliding surface is:

[0115]

[0116] Furthermore, based on the convoy coordinated braking consistency error equation and the error sliding surface, an adaptive parameter estimation law is set, the vehicle fault degree is estimated online based on the optimal parameter adaptive gain, and the online vehicle fault estimation value is obtained according to the different fault degrees of the vehicle, which is configured as follows:

[0117] Based on the platoon cooperative braking consistency error equation and error sliding surface, the adaptive parameter estimation law is set:

[0118]

[0119] An integral quadratic cost function with a discount factor is designed. By solving the minimum cost function, the optimal parameter adaptive gain is obtained to improve the online estimation response performance of the braking system fault degree.

[0120] Furthermore, an integral quadratic cost function with a discount factor is designed. By solving the minimum cost function, the optimal parameter adaptive gain is obtained and configured as:

[0121] Design an integral quadratic cost function with a discount factor:

[0122]

[0123] By solving the optimal integral quadratic cost function with discount factor, the optimal parameter adaptive gain is obtained, which satisfies the following dynamic equation:

[0124]

[0125] By minimizing the above integral cost function to obtain the optimal parameter adaptive gain, the fault parameter adaptive law can be optimized online to obtain the optimal parameter estimation dynamic response performance.

[0126] Furthermore, the queue distributed finite time adaptive fault-tolerant controller is configured as follows:

[0127]

[0128] Embodiment 3: This embodiment provides an electronic device corresponding to the distributed finite-time adaptive fault-tolerant control method based on vehicle queues provided in Embodiment 1. The electronic device may be an electronic device for a client, such as a mobile phone, a laptop computer, a tablet computer, a desktop computer, etc., to execute the method of Embodiment 1.

[0129] like Figure 3 As shown, the electronic device includes a processor, a memory, a communication interface and a bus, and the processor, the memory and the communication interface are connected through the bus to complete the communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Component (EISA) bus, etc. The memory stores a computer program that can be run on the processor, and when the processor runs the computer program, it executes the distributed finite-time adaptive fault-tolerant control method based on vehicle queues provided in the first embodiment. Those skilled in the art can understand that Figure 3The structure shown in the figure is only a block diagram of a part of the structure related to the scheme of the present application, and does not constitute a limitation on the computing device to which the scheme of the present application is applied. The specific computing device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0130] In some implementations, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), optical disk and other media that can store program codes.

[0131] In some other implementations, the processor may be a central processing unit (CPU), a digital signal processor (DSP), or other general-purpose processors of various types, which are not limited herein.

[0132] Embodiment 4: The distributed finite-time adaptive fault-tolerant control method based on a vehicle queue of the first embodiment may be specifically implemented as a computer program product. The computer program product may include a computer-readable storage medium on which computer-readable program instructions for executing the distributed finite-time adaptive fault-tolerant control method based on a vehicle queue of the first embodiment are loaded.

[0133] Computer readable storage media can be tangible devices that hold and store instructions used by instruction execution devices. Computer readable storage media can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any combination thereof.

[0134] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. In the description of this specification, the description of the reference terms "one embodiment", "some implementations", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0135] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes 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, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing 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.

[0136] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0137] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A distributed finite-time adaptive fault-tolerant control method based on vehicle platoons, characterized in that include: Construct the longitudinal kinematic equation of the vehicle and obtain the dynamic equation of the vehicle platoon consistency error; Design the sliding surface and sliding surface reaching law based on the vehicle platoon consistency error; Based on the vehicle platoon consistency error dynamics equation and the error sliding surface, an adaptive parameter estimation law is set, the vehicle fault degree is estimated online based on the optimal parameter adaptive gain, and an online vehicle fault estimation value is obtained according to different fault degrees of the vehicle; Combining the sliding surface approaching law, the vehicle platoon consistency error dynamics equation and the online vehicle fault estimation value, a distributed finite-time adaptive fault-tolerant controller for the platoon is obtained to achieve fault-tolerant control of the platoon in the event of a fault; wherein: Based on the vehicle platoon consistency error dynamics equation and error sliding surface, an adaptive parameter estimation law is set, and the vehicle fault degree is estimated online based on the optimal parameter adaptive gain. The online vehicle fault estimation value is obtained according to the different fault degrees of the vehicle, including: Based on the vehicle platoon consistency error dynamics equation and error sliding surface, the adaptive parameter estimation law is set: In the formula, P and Q are intermediate variables, H is the combined error variable of variables P, Q and the online estimated value of the fault degree θ; r is the integral variable, l(t) is the dynamic gain coefficient, and its lower limit is l L , the upper limit is l U ; Γ is the system adaptive gain, η 2 is the regularization coefficient, s is the sliding mode control quantity, α∈[0,1) is the power exponential term, κ1 is the gain coefficient, and the parameter is a sensitivity factor, which indicates the sensitivity of the forgetting factor function to parameter estimation errors. is the online estimation value of the actuator fault degree θ, x2 is the vehicle speed information, x 2f , G f , F f The expression is: In the formula, x 2f , G f , F f are the variables obtained after filtering of x2, G, and F, and the parameter k>0 is an adjustable parameter; m i is the mass of the i-th vehicle, u i is the braking force input of the i-th vehicle, f(t) is a function of vehicle wind resistance, rolling resistance and nonlinear disturbance of the road surface; An integral quadratic cost function with a discount factor is designed. By solving the minimum cost function, the optimal parameter adaptive gain is obtained to improve the online estimation response performance of the brake system fault degree, including: Design an integral quadratic cost function with a discount factor: In the formula, the operator exp(·) is the exponential operator, ν is the integral variable, and R0 is the coefficient of the quadratic form, whose value is greater than 0; By solving the optimal integral quadratic cost function with discount factor, the optimal parameter adaptive gain is obtained, which satisfies the following dynamic equation: By minimizing the above-mentioned integral quadratic cost function to obtain the optimal parameter adaptive gain, the fault parameter adaptive law can be optimized online to obtain the optimal parameter estimation dynamic response performance.

2. The distributed finite-time adaptive fault-tolerant control method based on vehicle platoon according to claim 1 is characterized in that: The longitudinal kinematic equation of the i-th vehicle in the platoon cooperative braking is: In the formula, x i represents the position of the i-th vehicle, v i is the speed of the ith vehicle, θ i represents the degree of failure of the vehicle's braking system, ρ is the air density, C A is the air resistance coefficient, A i is the frontal area of ​​the vehicle, g is the acceleration due to gravity, and f is the rolling damping coefficient.

3. The distributed finite-time adaptive fault-tolerant control method based on vehicle platoon according to claim 2 is characterized in that: Based on the longitudinal kinematic equation of the vehicle, the braking safety distance constraint is introduced, and according to the vehicle-to-vehicle communication topology, the vehicle platoon consistency error dynamic equation is obtained, including: In the formula, Represents the derivative of position and speed synchronization error, l ij and b i It is related to the topology of the fleet communication. i = 0 indicates complete failure. f(t) is a function of vehicle wind resistance, rolling resistance, and nonlinear disturbance of the road surface. is the derivative of the velocity of the jth vehicle, u0 is the braking deceleration input of the leading vehicle, and u i is the braking deceleration input of the i-th vehicle, and n is the number of vehicles following in the queue.

4. The distributed finite-time adaptive fault-tolerant control method based on vehicle platoon according to claim 1 is characterized in that: The design is based on the sliding surface of the vehicle platoon consistency error and the sliding surface reaching law, including: Based on the vehicle queue consistency error sliding surface s: s=e i2 +k1e i1 +k2|e i1 | γ sgn(e i1 ) The reaching law of the sliding surface is: In the formula, e i1 , e i2 They represent the vehicle position synchronization error and speed synchronization error respectively, k1, k2, k3, k4 are the adjustable gains of the controller, all of which are real numbers greater than zero, and α, γ∈[0,1) are power exponential terms.

5. The distributed finite-time adaptive fault-tolerant control method based on vehicle platoon according to claim 4 is characterized in that: The queue distributed finite-time adaptive fault-tolerant controller is designed as follows: Among them, M i is the generalized mass parameter of the vehicle, variable ε i is the disturbance error of the following vehicle i, and the parameter is the online adaptive estimate of the actual fault severity θ.

6. A distributed finite-time adaptive fault-tolerant control system based on vehicle platoons, characterized in that: The system includes: A first processing unit is configured to construct a longitudinal kinematic equation of the vehicle and obtain a vehicle platoon consistency error dynamic equation; The second processing unit is configured to design a sliding surface based on the vehicle queue consistency error and a sliding surface reaching law; The third processing unit is configured to set an adaptive parameter estimation law based on the vehicle platoon consistency error dynamics equation and the error sliding surface, estimate the vehicle fault degree online based on the optimal parameter adaptive gain, and obtain an online vehicle fault estimation value according to different fault degrees of the vehicle; The fourth processing unit is configured to combine the sliding surface approaching law, the vehicle queue consistency error dynamic equation and the online vehicle fault estimation value to obtain a queue distributed finite time adaptive fault-tolerant controller to achieve fault-tolerant control of the fleet in the event of a fault; wherein: Based on the vehicle platoon consistency error dynamics equation and error sliding surface, an adaptive parameter estimation law is set, and the vehicle fault degree is estimated online based on the optimal parameter adaptive gain. The online vehicle fault estimation value is obtained according to the different fault degrees of the vehicle, including: Based on the vehicle platoon consistency error dynamics equation and error sliding surface, the adaptive parameter estimation law is set: In the formula, P and Q are intermediate variables, H is the combined error variable of variables P, Q and the online estimated value of the fault degree θ; r is the integral variable, l(t) is the dynamic gain coefficient, and its lower limit is l L , the upper limit is l U ; Γ is the system adaptive gain, η 2 is the regularization coefficient, s is the sliding mode control quantity, α∈[0,1) is the power exponential term, κ1 is the gain coefficient, and the parameter is a sensitivity factor, which indicates the sensitivity of the forgetting factor function to parameter estimation errors. is the online estimation value of the actuator fault degree θ, x2 is the vehicle speed information, x 2f , G f , F f The expression is: In the formula, x 2f , G f , F f are the variables obtained after filtering of x2, G, and F, and the parameter k>0 is an adjustable parameter; m i is the mass of the i-th vehicle, u i is the braking force input of the i-th vehicle, f(t) is a function of vehicle wind resistance, rolling resistance and nonlinear disturbance of the road surface; An integral quadratic cost function with a discount factor is designed. By solving the minimum cost function, the optimal parameter adaptive gain is obtained to improve the online estimation response performance of the brake system fault degree, including: Design an integral quadratic cost function with a discount factor: In the formula, the operator exp(·) is the exponential operator, ν is the integral variable, and R0 is the coefficient of the quadratic form, whose value is greater than 0; By solving the optimal integral quadratic cost function with discount factor, the optimal parameter adaptive gain is obtained, which satisfies the following dynamic equation: By minimizing the above-mentioned integral quadratic cost function to obtain the optimal parameter adaptive gain, the fault parameter adaptive law can be optimized online to obtain the optimal parameter estimation dynamic response performance.

7. An electronic device, comprising at least a processor and a memory, wherein a computer program is stored in the memory, wherein: When the processor runs the computer program, the method described in any one of claims 1 to 5 is implemented.

8. A computer storage medium, characterized in that: Computer-readable instructions are stored thereon, and the computer-readable instructions can be executed by a processor to implement the method according to any one of claims 1 to 5.

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