Non-identical Vehicles Research Articles

Cooperative distance control of groups with non-identical vehicles over unknown time delay and directed network

Cooperative distance control of groups with non-identical vehicles over unknown time delay and directed network

Adaptive Centralized/Decentralized Control and Identification of 1-D Heterogeneous Vehicular Platoons Based on Constant Time Headway Policy

This paper deals with the adaptive control and identification of 1-D platoon of non-identical vehicles. Three common different topologies, such as predecessor following, bi-directional leader following, and two predecessors following are considered as the communication structures of platoon. For each topology, a new neighbor-based adaptive control law is introduced to estimate the parameter uncertainties, such as rolling resistance and air drag force coefficients. By presenting a new theorem, we prove that the estimates of unknown parameters converge to the actual values. Constant time headway policy is used to adjust the inter-vehicle spacing. For each topology, it is shown that the closed-loop dynamics of platoon is asymptotically stable. Afterward, the necessary conditions on control parameters assuring the string stability for each topology are derived by presenting further theorems. Moreover, the proposed methods are generalized for the heterogeneous platoons with time-varying network topology. Simulation results with different scenarios are provided to show the effectiveness of the presented approaches.

Third-order safe consensus of heterogeneous vehicular platoons with MPF network topology: Constant time headway strategy

In this paper the problem of centralized control of a platoon of non-identical vehicles under constant time headway strategy (CTHS) is investigated for multi predecessors following (MPF) topology. A centralized neighbor based linear control law using relative position and velocity is considered for each vehicle. Due to communication and parasitic delays and time-varying network topology, the closed-loop dynamics of platoon is in the form of a multiple delayed switched linear system. New approaches are developed to perform the internal stability analysis of one-dimensional heterogeneous vehicular platoons. Afterwards, sufficient conditions assuring the string stability of a platoon under MPF topology are obtained by presenting a new theorem. In continuance of the paper, some conditions on control parameters guaranteeing safety of the platoon in an emergency braking maneuver are presented through a new theorem. Several simulation results are provided to show the effectiveness of the proposed methods.

Design, analysis and performance evaluation of a third order distributed protocol for platooning in the presence of time-varying delays and switching topologies

This paper is concerned with the problem of designing a decentralized consensus protocol for platooning of non-identical vehicles in the presence of heterogeneous time-varying communication delays. The proposed control protocol makes use of a state feedback and to this aim drivetrain dynamics are modeled as third-order linear systems. Necessary and sufficient conditions for convergence and exponential stability, derived by using an appropriate Krasovskii functional, demonstrate the ability of the platoon in reaching the required regime with an exponentially bounded behavior. The proposed LMI-based approach allows to estimate both delay margin and decay rate. Moreover, convergence is proven under switching communication network topologies by means of a Lyapunov-Razumikhin function, and the assessment of a string stable behavior has been also theoretically investigated. High-fidelity simulations with Plexe show the effectiveness of the theoretical results in different driving conditions and in the presence of external disturbances and communication impairment. Different communication channel models are used in the validation stage to further prove robustness of the proposed methodology with respect hard delay and packets losses.

Aircraft Ground Service Scheduling Problems and Their Genetic Algorithm With Hybrid Assignment and Sequence Encoding Scheme

The aircraft ground service is a key ring to guarantee flight safety and normal operation. In the case of the traveling time of service crew from one aircraft parking place to another to be nonignorable, the scheduling optimization problem of ground service can be described as a vehicle routing problem with time windows of multiply nonidentical vehicles. To solve the problem, we propose a genetic algorithm with a hybrid encoding scheme. The encoding scheme describes the bit of a chromosome as a positive real number. Its integer part stands for the assigned crew of a flight and its decimal part for the position in job sequence by percent. The encoding scheme integrates assignment and sequence information in one number. Thus, it can be conveniently processed by all genetic operations of crossover, mutation, selection, and reproduction. A greedy heuristic is embedded as the sequencing initialization and reinitialization tool in the genetic algorithm procedure. The genetic algorithm is used to solve a lot of examples from a practical aircraft service company. The achieved results show that the algorithm is efficient.

Design and Implementation of a Robust Controller for Lateral and Longitudinal Dynamics of an Autonomous Vehicle

In this paper a robust controller design task for longitudinal and lateral dynamic of non-identical autonomous road vehicles is considered. In order to use identical controllers for different vehicles the varying parameters are regarded as unstructured model uncertainties. How unstructured model uncertainties are described and how they are taken into account during the controller design process is shortly presented.The used control concept for plants with model uncertainties in form of a standard H_control task is described. The resulting longitudinal and lateral control laws for nonidentical vehicles are discussed concerning the varying vehicle parameters. The first practical results with respectively one control law for longitudinal and lateral dynamic of non-identical autonomous vehicles are presented. It is shown that through the appropriate choice of design parameters, varying vehicle dynamics can be taken into account without substantial losses regarding accuracy and dynamics.

A systematic antiwindup strategy and the longitudinal control of a platoon of vehicles with control saturations

Current methodologies for designing control systems usually ignore the effects of control saturations. For vehicle platooning, this can be especially disastrous since the performance of a platoon of nonidentical vehicles is, in general, severely limited by saturating control signals. This paper presents a systematic design procedure for adapting a nominal controller, designed without regard to control saturation, to a higher performance nonlinear controller that explicitly accounts for the saturating nonlinearities while preserving stability. In particular, the error governor (EG) scheme proposed by P. Kapasouris et al. (1988) is extended and applied to the IVHS problem found by S. Sheikholeslam (1990). This extension is a less conservative strategy that explicitly accounts for an important class of controller designs, including proportional control and a class of nonlinear feedback designs. Results of the study demonstrate that severe windup found in nominal platooning applications can systematically be eliminated without loss of steady-state performance. This significantly increases the range of maneuvers open to the lead vehicle, thus enhancing the utility of a proposed design. An extensive simulation of a 15-car platoon of nonidentical vehicles with nonlinear vehicle models illustrates these results.

A System Level Study of the Longitudinal Control of a Platoon of Vehicles

This paper presents a preliminary system study of a longitudinal control law for a platoon of nonidentical vehicles using a simplified nonlinear model for the vehicle dynamics. This study advances the art of automatic longitudinal control for a platoon of vehicles in the sense that it considers longer platoons composed of nonidentical vehicles; furthermore, the longitudinal control laws presented in this study take advantage of communication possibilities not available in the recent past. We assume that for i = 1, 2, . . . vehicle i knows at all times vl and al (the velocity and acceleration of the lead vehicle) in addition to the distance between vehicle i and the preceding vehicle, i − 1. A control law is developed and is tested on a simulation of a platoon of 16 vehicles where the lead vehicle increases its velocity at a rate of 3 m.s−2; it is shown that the distance between successive vehicles does not change by more than 0.12 m in spite of variations in the masses of the vehicles (from the nominal), of communication delay and of noise in measurements.