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Cascade compensation mechanism was designed to improve the dynamical performance of traffic flow system. Two compensation methods were used to study unit step response in time domain and frequency characteristics with different parameters. The overshoot and phase margins are proportional to the compensation parameter in an underdamped condition. Through the comparison we choose the phase-lead compensation method as the main strategy in suppressing the traffic jam. The simulations were conducted under two boundary conditions to verify the validity of the compensator. The conclusion can be drawn that the stability of the system is strengthened with increased phase-lead compensation parameter. Moreover, the numerical simulation results are in good agreement with analytical results. [ABSTRACT FROM AUTHOR]

To study the signal control strategy for reducing traffic emission theoretically, we first presented a kind of discrete traffic flow model with relative speed term based on traditional coupled map car-following model. In the model, the relative speed difference between two successive running cars is incorporated into following vehicle’s acceleration running equation. Then we analyzed its stability condition with discrete control system stability theory. Third, we designed a delay-feedback controller to suppress traffic jam and decrease traffic emission based on modern controller theory. Last, numerical simulations are made to support our theoretical results, including the comparison of models’ stability analysis, the influence of model type and signal control on CO 2 emissions. The results show that the temporal behavior of our model is superior to other models, and the traffic signal controller has good effect on traffic jam suppression and traffic CO 2 emission, which fully supports the theoretical conclusions. [ABSTRACT FROM AUTHOR]

A speed feedback control mechanism was introduced into the system to improve the dynamical performance of the traffic flow. The modern control theory was used to analyze the stability of the system. It is found that the stability region varies with the feedback coefficient proportionally. In addition, the unit step responses in time domain and phase–frequency curves in frequency domain were given with different feedback coefficients in step response diagram and Bode diagram respectively. The overshoot and phase margins are inversely proportional to the speed feedback coefficients in an underdamped condition. The simulations were conducted to verify the validity of the improvement. The conclusion can be drawn that the analytical result and the simulation result are in good agreement with each other. [ABSTRACT FROM AUTHOR]

Abstract: Traffic flow system’s stability analysis can be seen as a typical control system problem, which has three kinds of damping ratio properties from the viewpoint of control theory. To discover the damping ratio characteristics of traffic flow system under sudden outer impulse, firstly, we proposed a new method to build the traffic flow model based on state space theory. Secondly, we deduced one form of state transfer matrix from system closed-loop transfer function reversely. Lastly, we fully investigated the proportional–differential effects in the traffic car-following model system analytically and numerically. For unsteady traffic flow system with the proportional–differential (PD) term, in order to suppress the traffic jam, we derived a kind of decoupled delay-feedback control algorithm, which used -norm and the numerical simulation method to find the feedback gain and delay time . The traffic flow system’s transient performance formula was presented with and without PD term, and we found out the important impact of PD term on traffic flow system’ stability. The numerical simulation results substantiate our theoretical and analytical results. [Copyright &y& Elsevier]