Full velocity difference and acceleration model for a car-following theory

In order to describe the car-following behavior more actually in real traffic, a full velocity difference and acceleration model (for short, FVDAM) is proposed by synthetically taking into account headway, velocity difference and acceleration of the leading car on the basis of full velocity difference model. The analytical method and numerical simulation results show that the proposed model can describe the phase transition of traffic flow and estimate the evolution of traffic congestion, that incorporating the acceleration of the leading car into car-following model can stabilize traffic flow, suppress the traffic jam and increase capacity, and that the following car in FVDAM can accelerate more quickly than in FVDM.     

A discrete time car following model and the bi-parameter logistic map

A discrete time model for car following behaviour is investigated. It is found that the model can be expressed in the form of a logistic map with multiple control parameter values. The case where the logistic map has a bi-value control parameter is investigated and relevant Feigenbaum diagrams are presented and the behaviour of the Lyapunov exponent is investigated. Divergent behaviour in the chain of vehicles is also considered.     

Classroom note: Inattentive drivers: making the solution method the model

A simple car following model based on the solution of coupled ordinary differential equations is considered. The model is solved using Euler's method and this method of solution is itself interpreted as a mathematical model for car following. Examples of possible classroom use are given.     

A novel GCM chaotic neural network for information processing

A new chaotic neural network named “globally coupled map using sine map(SI-GCM)”, which is a modified Kaneko’s globally coupled map model, is proposed. With the introduction of sine map and chaotic neurons’ different way of coupling, it exhibits rich dynamic behaviors. By adopting a variable threshold parameter control method, it can be controlled to specified-period orbit. Furthermore, the controlled SI-GCM has excellent associative memory performance. It can not only output unique fixed pattern, but also output periodic patterns which contain the stored pattern closest to the initial pattern. Simulation results suggest that SI-GCM is fit for information processing.     

Trajectory stabilization of a model car via fuzzy control

This paper deals with trajectory stabilization of a computer simulated model car via fuzzy control. Stability conditions of fuzzy systems are given in accordance with the definition of stability in the sense of Lyapunov. First, we approximate a computer simulated model car, whose dynamics is nonlinear, by T-S (Takagi and Sugeno) fuzzy model. Fuzzy control rules, which guarantee stability of the control system under a condition, are derived from the approximated fuzzy model. The simulation results show that the fuzzy control rules effectively realize trajectory stabilization of the model car along a given reference trajectory from all initial positions under a condition and the dynamics of the approximated fuzzy model agrees well with that of the model car.     

Stabilization of traffic flow in optimal velocity model via delayed-feedback control

Traffic jams may occur due to various reasons, such as traffic accidents, lane reductions and on-ramps. In order to suppress the traffic congestion in an optimal velocity traffic model without any driver’s delay taken into account, a delayed-feedback control of both displacement and velocity differences is proposed in this study. By using the delay-independent stability criteria and the H_∞-norm, the delayed-feedback control can be determined to stabilize the unstable traffic flow and suppress the traffic jam. The numerical case studies are given to demonstrate and verify the new control method. Furthermore, a comparison is made between the new control method and the method proposed by Konishi et al. [K. Konishi, M. Hirai, H. Kokame, Decentralized delayed-feedback control of an optimal velocity traffic model, Eur. Phys. J. B 15 (2000) 715–722]. The results show that the new control method makes the traffic flow more stable and improves the control performance.     

Investigation of a traffic modelling inspired two dimensional map

Commencing with a class of differential equation based car following models for traffic flow a simplified discrete time model on a closed loop is found. A two dimensional map, containing two free parameters, and corresponding to the behaviour of two vehicles on the loop is investigated. Bounds on the prisoner set of the map are determined, and a number of strange attractors are presented. The variation of largest Lyapunov exponent over a range of parameter space is considered. The resulting behaviour of the map is considered within a traffic flow context.     

A car-following collision prevention control device based on the cascaded fuzzy inference system

A car-following collision prevention control device based on the cascaded fuzzy inference system (CFIS), consisting of a velocity fuzzy controller and an acceleration fuzzy controller, to nonlinearly control car acceleration or deceleration rate is proposed. The distance and speed relative to the car in front are measured using spread spectrum radar and applied to the collision prevention control device. The output acceleration or deceleration rate obtained from the CFIS car-following collision prevention system is based on the characteristics of the vehicle. The simulation results demonstrate that the presented CFIS control device can solve the oscillation problems for final relative distance between the lead vehicle (LV) and following vehicle (FV) and relative speed. When the LV applies the brake suddenly or a stationary obstacle appears in front of vehicle moving at high speed on the roadway, the CFIS control device can safely avoid a collision. The CFIS car-following collision prevention control device proposed in this paper can provide a safe, reasonable and comfortable drive.     

Optimal Control of an Elastic Tyre-Damper System with Road Contact

We study an elastic tyre with a wheel rim that is suspended at the chassis of a car by means of a spring-damper element. This quarter car model may be controlled by varying the damping constant of the electrorheological damper. Our mathematical model yields a coupled ODE-PDE problem with a free boundary at the tyre-road contact. In this study we approximate the tyre by the Hertz contact stress formula. The resulting optimal control problem with control constraints is solved numerically. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Microscopic modeling and control logic for incident-responsive automatic vehicle movements in single-automated-lane highway systems

Automatic response to lane-blocking incidents is a critical issue in the field of automated highway systems (AHS). Accordingly, this paper presents a microscopic vehicular control methodology for automatic-control (AC) vehicular movements in response to lane-blocking incidents in the AHS environment. The embedded traffic control logic is based on the basic safety requirements for automatic-control lane traffic maneuvers responding to lane-blocking incidents in the single-automated-lane AHS environment. Accordingly, respective automated vehicular control models are proposed to deal with AC vehicles moving in three corresponding sequential phases, i.e., (1) AC platoon approaching the incident site from the blocked lane, (2) mandatory lane changing and mixed car following in the adjacent lane, and (3) AC platoon reforming downstream from the incident site in the blocked automated lane. Using a microscopic simulation model which embeds these proposed models, preliminary tests are conducted to investigate the relative performance of the proposed method in various traffic flow and control scenarios. The resulting numerical results, including simplified sensitivity analyses, indicate that the proposed microscopic traffic control logic permits regulating automatic-control vehicular movements in response to the effects of lane-blocking incidents on traffic flows either in control-free lanes or in the automatic-control lanes. Implications of the results and some findings are discussed for further research.     

Optimal control of a slot car racer

In this contribution, we present a simulation method for the optimal control of a mechatronic system that is based on discrete variational calculus and apply it to compute the time-minimal path of a slot car racer. Here, the DMOC (Discrete Mechanics and Optimal Control [4]) method is used to generate offline optimal trajectories for the electro-mechanically coupled system, i.e. sequences of discrete configurations and sequences of driving voltages. The time-minimal path is achieved by the choice of different cost functions, the sum of time steps, the negative sum of the quadratic momenta and the negative sum of the quadratic velocities. Simulation results show that the momentum formulation yields the lowest number of iterations. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

CML模型和湍流的非线性

本文在现有耦合映射格点(CML)动力系统模型的基础上,提出了能够同时模拟对流项和扩散项的强弱耦合系统的CML模型,分析了这类模型的特点和结构.数值试验表明,这类CML模型能够有效地研究时空复杂性,利用数值模拟的结果对湍流的物理机制作了初步的阐释.     

A graph‐theoretic method to stabilize the delayed coupled systems on networks based on periodically intermittent control

This paper mainly focus on the exponential stabilization problem of coupled systems on networks with mixed time‐varying delays. Periodically intermittent control is used to control the coupled systems on networks with mixed time‐varying delays. Moreover, based on the graph theory and Lyapunov method, two different kinds of stabilization criteria are derived, which are in the form of Lyapunov‐type theorem and coefficients‐type criterion, respectively. These laws reveal that the stability has a close relationship with the topology structure of the networks. In addition, as a subsequent result, a decision theorem is also presented. It is straightforward to show the stability of original system can be determined by that of modified system with added absolute value into the coupling weighted‐value matrix. Finally, the feasibility and validity of the obtained results are demonstrated by several numerical simulation figures.     

时空Chaos研究中的CML模型

通过对有关差分格式的稳定性分析，我们提出了一类新的格点耦合映射（ＣＭＬ）模型。数值试验表明：我们提出的ＣＭＬ模型是一类有效的研究时空复杂性的模型，特别是对于强耦合系统。     

基于交互式并行驾驶模拟实验的跟驰状态汽车驾驶倾向性动态辨识模型验证方法

驾驶倾向性的实时识别是实现汽车辅助驾驶尤其是主动安全预警系统智能化的关键理论和技术.通过交互式并行模拟驾驶实验获取跟驰状态下各倾向性类型的行车数据对建立的驾驶员倾向性的动态辨识模型进行验证,并将验证结果与心理问卷测试的结果相对比.结果表明所建辨识模型可行,能够实现对跟驰状态下驾驶员倾向性类型的实时识别,为个性化汽车主动安全系统的实现提供理论基础.     

The Simulation of Some Simple Control Policies for a Signalized Intersection

The authors present the results of some simulation studies concerned with the computer control of signalized intersections. The simplest model considered is that of two competing random streams. The transient response and delay/flow characteristics of some simple control procedures are investigated. These are based on the Dunne-Potts policy in which the traffic light is switched when the queue of the road with right of way has been dispersed.The model is then developed to consider four competing streams and the control policies are modified accordingly. Similar results to the two-stream case are presented. In the final section turning vehicles are considered by including eight competing streams in the intersection model.     

Principal Component Analysis from the Multivariate Familial Correlation Matrix

This paper considers principal component analysis (PCA) in familial models, where the number of siblings can differ among families. S. Konishi and C. R. Rao (1992, Biometrika79, 631–641) used the unified estimator of S. Konishi and C. G. Khatri (1990, Ann. Inst. Statist. Math.42, 561–580) to develop a PCA derived from the covariance matrix. However, because of the lack of invariance to componentwise change of scale, an analysis based on the correlation matrix is often preferred. The asymptotic distribution of the estimated eigenvalues and eigenvectors of the correlation matrix are derived under elliptical sampling. A Monte Carlo simulation shows the usefulness of the asymptotic expressions for samples as small as N=25 families.     

Chaos control in passive walking dynamics of a compass-gait model

The compass-gait walker is a two-degree-of-freedom biped that can walk passively and steadily down an incline without any actuation. The mathematical model of the walking dynamics is represented by an impulsive hybrid nonlinear model. It is capable of displaying cyclic motions and chaos. In this paper, we propose a new approach to controlling chaos cropped up from the passive dynamic walking of the compass-gait model. The proposed technique is to linearize the nonlinear model around a desired passive hybrid limit cycle. Then, we show that the nonlinear model is transformed to an impulsive hybrid linear model with a controlled jump. Basing on the linearized model, we derive an analytical expression of a constrained controlled Poincaré map. We present a method for the numerical simulation of this constrained map where bifurcation diagrams are plotted. Relying on these diagrams, we show that the linear model is fairly close to the nonlinear one. Using the linearized controlled Poincaré map, we design a state feedback controller in order to stabilize the fixed point of the Poincaré map. We show that this controller is very efficient for the control of chaos for the original nonlinear model.     

A keyed hash function based on the modified coupled chaotic map lattice

In this paper, we propose a dedicated keyed hash algorithm based on the modified coupled chaotic map lattice. By using the nearest and long distance couplings, both the key and the message as the parameters of the coupled map lattice, the expansion key and the nonlinear transformation, the system has enough confusion and diffusion rate between the message and the key. The structure of the system provides strong collision resistance and high performance efficiency. Simulation results show that the system has a uniform and random distribution of hash value, and fast performance.     

Planning Formula One race strategies using discrete-event simulation

A discrete-event simulation model that imitates most on-track events, including car failures, passing manoeuvres and pit stops during a Formula One race, is presented. The model is intended for use by a specific team. It will enable decision-makers to plan and evaluate their race strategy, consequently providing them with a possible competitive advantage. The simulation modelling approach presented in this paper captures the mechanical complexities and physical interactions of a race car with its environment through a time-based approach. Model verification and validation are demonstrated using three races from the 2005 season. The application of the model is illustrated by evaluating the race strategies employed by a specific team during these three races.