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CN-121979223-A - Safety constraint vehicle formation distributed sliding mode control method based on preset performance function

CN121979223ACN 121979223 ACN121979223 ACN 121979223ACN-121979223-A

Abstract

The invention relates to a safety constraint vehicle formation distributed sliding mode control method based on a preset performance function, which solves the defect that the vehicle formation control is difficult to simultaneously meet the safety constraint, the preset performance and the distributed cooperative control compared with the prior art. The method comprises the following steps of establishing a three-step state space model of vehicle formation, generating a smooth reference track of the following vehicle, designing preset performance constraint of the following vehicle, calculating expected speed of the following vehicle, calculating expected torque of the following vehicle, controlling a driving system of the following vehicle and realizing formation cooperative control. According to the invention, through a constraint-aware reference generation mechanism, a preset performance function with a self-adaptive boundary and a topological structure approach law, high-performance tracking of the pilot vehicle track is realized on the premise that all following vehicles meet a time-varying safety boundary.

Inventors

  • CAO DEWEN
  • ZHAN YULIN
  • WU JIAN

Assignees

  • 安庆师范大学

Dates

Publication Date
20260505
Application Date
20260209

Claims (10)

  1. 1. The distributed sliding mode control method for the formation of the safety constraint vehicles based on the preset performance function is characterized by comprising the following steps of: 11 Building a three-order state space model of vehicle formation; 12 Generating a smooth reference track of the follower vehicle; 13 Designing preset performance constraints of the following vehicle; 14 Calculating the expected speed of the following vehicle; 15 Calculating a desired torque of the follower; 16 Controlling the follower drive system; 17 A team cooperative control is realized.
  2. 2. The method for controlling a distributed sliding mode of a safety restraint vehicle formation based on a preset performance function according to claim 1, wherein the step of establishing a three-step state space model of the vehicle formation comprises the following steps: 21 Describing a formation communication structure comprising 1 pilot vehicle and N following vehicles by adopting a directed graph, defining an adjacency matrix, a Laplace matrix and a pilot vehicle connection matrix, and describing communication relations and topological characteristics among vehicles; 22 Building a longitudinal dynamics model of the following vehicle A third-order dynamics model of the longitudinal position, speed and driving torque of the vehicle following vehicle describes the longitudinal movement characteristics of the vehicle; 23 (ii) converting to a relative deviation state space model, defining a first The position deviation, the speed deviation and the torque deviation of the vehicle following vehicle relative to the pilot vehicle convert the absolute dynamics of the vehicle into a three-order deviation state space model relative to the pilot vehicle, and the pilot vehicle is taken as a reference standard, so that the design of a distributed cooperative control law is facilitated.
  3. 3. The distributed sliding mode control method for forming safety constraint vehicles based on a preset performance function according to claim 1, wherein the step of generating a smooth reference track of a following vehicle is to design a constraint perception reference generation mechanism of a time-varying safety margin based on a pilot vehicle position and a formation expected vehicle distance, and generate a smooth reference signal meeting a time-varying safety boundary through dynamic adjustment of the safety margin and track smoothing processing, and comprises the following steps: 31 Setting a formation configuration and designing a time-varying safety margin, namely setting a desired inter-vehicle distance and a time-varying safety constraint boundary as a first vehicle distance Vehicle following vehicle design time varying safety margin: , Wherein: Is the first A time-varying safety margin of the vehicle describing a buffer distance between the reference trajectory and the safety boundary; providing a larger safety margin for the initial safety margin value in the formation starting stage; Forming a minimum safety margin which is maintained after the formation is stable as a final safety margin value; controlling the amplitude of margin attenuation as a margin gain coefficient; Controlling the rate at which the margin decays from the initial value to the final value for the margin decay coefficient; Is run time; The margin design is used for gradually tightening the safe buffer distance to a compact steady state value from an initial conservative value along with the formation state, and starting safety and steady state tracking precision are considered; 32 Generating a constraint-aware reference signal based on a time-varying safety margin, generating a reference signal satisfying a boundary constraint: , Wherein: Is the first A constraint reference signal of the vehicle; Is an initial position reference; 、 the method comprises the steps of changing a lower boundary and an upper boundary respectively, setting a reference signal as the lower boundary margin when an initial reference is lower than the lower boundary margin, keeping an original value when the initial reference is within a safety range, and setting the reference signal as the upper boundary margin when the initial reference is higher than the upper boundary margin; 33 Smoothing and defining tracking error by Hermite interpolation for discontinuous time of constraint reference signal to generate final smooth safe reference track And define the first Position tracking error of a vehicle follower , The actual position of the ith following vehicle is used as a control object for the design of a subsequent control law.
  4. 4. The method for controlling the distributed sliding mode of the safety constraint vehicle formation based on the preset performance function according to claim 1, wherein the preset performance constraint of the design follower vehicle is that a preset performance function with a self-adaptive boundary is built for each follower vehicle, and a finite position tracking error is mapped to an unbounded space by adopting an unskilled error transformation, so that control singularity is avoided and transient error peaks are restrained in the control process, and the method comprises the following steps: 41 Design of a preset performance boundary function design of a preset performance function with an adaptive boundary , Wherein As a basis for the performance boundary of the device, Is an adaptive boundary component, a basic performance boundary The design is as follows: , Wherein: for the initial performance boundary, satisfy Allowing a larger tracking error in the start-up phase of the formation; as a final performance boundary, tracking accuracy required to be achieved after formation is stable; for a preset convergence time, controlling a time scale of decay from an initial boundary to a final boundary; is the current run time; 42 Design adaptive boundary dynamics: adaptive boundary components are generated by differential equations: , Wherein: time derivatives that are adaptive boundary components; Controlling the attenuation rate of the self-adaptive boundary for the self-adaptive boundary attenuation coefficient; controlling the influence intensity of errors on the boundary for the self-adaptive gain coefficient; Controlling the sensitivity of the adaptive boundary to error changes for the sensitivity index parameter; tracking error for time delay position; Is a time delay parameter for avoiding high frequency oscillations; 43 Applying performance constraints and performing an error transformation that requires the position tracking error to satisfy the performance constraints: , The initial conditions are as follows: , Defining a normalization error: , The singular error free transformation is adopted: , Wherein: Is the first The position of the vehicle following the vehicle tracks the error, In order to preset the performance constraints of the device, Indicating that it is true for all non-negative moments, ensuring that the position tracking error is always within a prescribed range, initial conditions ensuring that the initial error meets performance requirements and does not violate security constraints, wherein 、 Respectively time-varying upper and lower boundaries at the initial time; to normalize the error, have no dimension, take the range of values Normalizing the bounded error; Is free of singular transformation error, dimensionless and value range Wherein As a natural logarithmic function, the transformation ensures that when Time of day The bounded normalized error is mapped to an unbounded space.
  5. 5. The method for controlling the distributed sliding mode of the safe restraint vehicle formation based on the preset performance function, which is disclosed by claim 1, is characterized in that the calculation of the expected speed of the following vehicles is that a position tracking layer virtual control law is designed based on singular error free transformation, and an expected speed instruction is deduced for each following vehicle through a Lyapunov method, and the method comprises the following steps: 51 A position error dynamic equation is constructed, namely, the transformation derivative without singular errors of the following vehicle is obtained, and the relation between the time derivative of the transformation error and the position tracking error derivative and the preset performance boundary change rate is obtained; 52 Design position tracking control law based on Lyapunov stability theory, the first Vehicle following design position layer expected dynamic : , Wherein: Gain is controlled for the position layer; The control law ensures that the transformation error decays to zero at an exponential rate, thereby ensuring that the original position tracking error converges to within a preset performance boundary; 53 Generating the desired speed command by the feedback of the position tracking control law as the first The vehicle follower generates a desired speed command including a reference trajectory feedforward term, a position error feedback term, a performance boundary compensation term, and a transformation error compensation term.
  6. 6. The method for controlling the distributed sliding mode of the safety restraint vehicle formation based on the preset performance function according to claim 1, wherein the calculation of the expected torque of the following vehicles is to design a virtual control law of a speed tracking layer based on an expected speed command and an actual speed deviation, and deduce the expected driving torque for each following vehicle through a Lyapunov method, and the method comprises the following steps: 61 Definition of speed tracking error, definition of the first The difference between the actual speed deviation of the vehicle following vehicle and the expected speed command is the speed tracking error ; 62 Design speed tracking control law based on Lyapunov stability theory, the first Vehicle following design speed layer desired dynamics : , Wherein: Gain is controlled for the velocity layer; The control law ensures that the velocity tracking error converges to zero at an exponential rate; 63 Generating a desired driving torque instruction for the ith following vehicle by combining a longitudinal dynamics model of the following vehicle and performing reverse thrust through a speed tracking control law The method comprises a desired acceleration feedforward term, a speed error feedback term, an air resistance compensation term and a pilot vehicle acceleration compensation term.
  7. 7. The method for controlling a distributed sliding mode of a safety restraint vehicle formation based on a preset performance function according to claim 1, wherein the method for controlling a driving system of a following vehicle is characterized in that a distributed sliding mode surface is constructed based on torque errors weighted by vehicle communication topology, a distributed sliding mode controller is designed by adopting a topological structure approach law, and a driving system control input of each following vehicle is generated, and the method comprises the following steps: 71 Defining torque tracking error, defining the first The difference between the actual driving torque deviation of the vehicle following vehicle and the expected driving torque deviation is the torque tracking error ; 72 Constructing a distributed sliding mode surface based on a vehicle formation communication topological structure, for the first Building a distributed sliding mode surface by a vehicle following vehicle: , Wherein: Is the first The individual sliding mode surface of the vehicle following vehicle reflects the torque tracking state of the vehicle and the communication neighbors of the vehicle; Is the total number of following vehicles; Describing communication connection relation among vehicles as adjacent matrix elements; Is the first Torque tracking error of the vehicle following vehicle; the connection coefficient is the pilot vehicle connection coefficient; the collective sliding surfaces of all follower vehicles are represented in vector form , Wherein the method comprises the steps of As a collective slip-plane vector, In order to be a laplace matrix, In order to connect the matrix to the pilot vehicle, Is a torque error vector; 73 Design topological structure approach law, namely design topological structure approach law for suppressing sliding mode control buffeting and ensuring limited time to arrive: , Wherein: Is the first Time derivative of the vehicle slip plane; to get the gain of the approach law proportion, the speed of approaching the sliding mode surface is controlled; Switching gain for an approach law; is a boundary layer function and is used for inhibiting high-frequency buffeting; is a boundary layer thickness parameter; 74 Generating a distributed control input by approach law and torque error dynamics, no Vehicle following vehicle generated drive system control input The inclusion of a feedback control term based on the slip plane and a feedforward compensation term for the desired torque ensures that the system reaches the slip plane and gradually converges steadily along the slip plane in a finite time.
  8. 8. The distributed sliding mode control method for forming safety constraint vehicles based on a preset performance function according to claim 1, wherein the implementation of the cooperative control of forming is to verify the finite time accessibility of a sliding mode surface and the asymptotic stability of tracking errors based on Lyapunov theory, and issue control instructions through a vehicle-mounted controller to enable all following vehicles to cooperatively follow a pilot vehicle track on the premise of meeting safety constraint and preset performance, and the method comprises the following steps: 81 Verifying limited time accessibility of the slip plane drive system control input Based on Lyapunov theory, the arrival phase performance of the distributed sliding mode control system is verified, and the upper limit of the arrival time of the sliding mode surface is proved to be: , Wherein: The sliding mode surface reaches the upper limit of time; 2-norm for the initial collective die face; Switching gain for an approach law; Is a matrix Representing the connectivity strength of the communication topology; 82 Verifying the asymptotic stability of the tracking error based on Lyapunov theory, when the control gain satisfies And is also provided with At this time, the position and velocity tracking errors of all the following vehicles asymptotically converge to zero: , Wherein: Is the first Position tracking error of vehicle follower, Is a velocity tracking error; 、 The control gains of the position layer and the speed layer are respectively controlled, and the conditions ensure that the following vehicle finally accurately tracks the expected track; 83 The multi-performance constraint collaborative following is realized, namely, a control command is issued through a vehicle-mounted controller, so that all following vehicles simultaneously meet the following three performance constraints: (1) The preset performance constraint that the position tracking error always meets , Ensures that the transient and steady state performance of the tracking error meets the preset index, Is the first Preset performance boundaries of the vehicle following vehicle; (2) Safety boundary constraint that the following vehicle position always meets , Ensuring the running safety of the vehicle, For the time-varying lower boundary of the band, For the i-th actual position of the following vehicle, As the time-varying upper boundary of the band, Time is; (3) Asymptotically convergence performance, namely asymptotically converging the position and speed tracking errors of all the following vehicles to zero, and ensuring the final stability of formation.
  9. 9. A computer readable storage medium, wherein a computer program is stored on the storage medium, and when the computer program is executed by a processor, the method for controlling the formation of a distributed sliding mode of a safety restraint vehicle based on a preset performance function according to any one of claims 1 to 8 can be implemented.
  10. 10. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the method for distributed sliding mode control of a safety restraint vehicle formation based on a preset performance function as claimed in any one of claims 1 to 8.

Description

Safety constraint vehicle formation distributed sliding mode control method based on preset performance function Technical Field The invention relates to the technical field of multi-agent system control, in particular to a safety constraint vehicle formation distributed sliding mode control method based on a preset performance function. Background Currently, there are numerous branches in the study of control problems of a vehicle formation system, including consistency control, formation control, cluster control, etc., wherein consistency control is the basis and core of other study branches. The consistency control of the vehicle formation system means that by designing a proper control protocol for each agent, the agent can interact with the neighbor only, and finally, all agents can reach the same target state. Through development of the last twenty years, the consistency research of the vehicle formation system gradually tends to be mature, and important directions such as average consistency, limited time consistency and the like are derived. In actual vehicle platoon operation, each vehicle needs to meet time-varying safety constraints due to road environmental complexity, traffic regulatory constraints, and vehicle physical performance limitations. For example, the vehicle needs to stay within the lane boundary, avoid collisions, meet space constraints, and the like. These safety constraints typically vary dynamically with road conditions, weather conditions, and traffic flow. Conventional formation control methods tend to ignore these security constraints, which may lead to violation of traffic rules or occurrence of security incidents. Meanwhile, the control performance requirements of the vehicle formation system are increasingly strict. Besides the requirement that the system reaches the expected formation configuration, transient performance indexes such as overshoot, convergence speed, steady state error and the like are also required to be restrained. The preset performance control method can pre-designate transient and steady state performance boundaries of the system by designing a performance function. However, the conventional preset performance function adopts a fixed boundary, so that the reference signal abrupt change is difficult to adapt, and transient error peaks can be caused to exceed expectations. In addition, the vehicle queuing system is a typical distributed multi-agent system, and each vehicle can only acquire limited information of own states and neighboring vehicles through on-board sensors and communication devices. The centralized control method requires global information, increases communication burden and reduces system reliability and scalability. Therefore, the distributed controller is designed, so that each vehicle can realize cooperative control only by means of local information, and the distributed controller has important theoretical significance and practical application value. Therefore, there is a need to implement a distributed sliding mode control method for formation of safety restraint vehicles based on a preset performance function, so as to solve the above technical problems. Disclosure of Invention The invention aims to solve the defect that the vehicle formation control in the prior art is difficult to simultaneously meet safety constraint, preset performance and distributed cooperative control, and provides a safety constraint vehicle formation distributed sliding mode control method based on a preset performance function to solve the problems. In order to achieve the above object, the technical scheme of the present invention is as follows: a safety constraint vehicle formation distributed sliding mode control method based on a preset performance function comprises the following steps: establishing a three-order state space model of vehicle formation; Generating a smooth reference track of the following vehicle; designing preset performance constraints of the following vehicle; calculating the expected speed of the following vehicle; calculating the expected torque of the following vehicle; Controlling a follower driving system; and realizing formation cooperative control. The method for establishing the three-order state space model of the vehicle formation comprises the following steps of: constructing a vehicle formation communication topology, namely describing a formation communication structure comprising 1 pilot vehicle and N following vehicles by adopting a directed graph, defining an adjacency matrix, a Laplace matrix and a pilot vehicle connection matrix, and describing communication relations and topological characteristics among vehicles; establishing a longitudinal dynamics model of the following vehicle A third-order dynamics model of the longitudinal position, speed and driving torque of the vehicle following vehicle describes the longitudinal movement characteristics of the vehicle; conversion to a relative deviation State space mo