Freeway traffic flows can be controlled by lumped parameter system approach owing to the space discretized system models. Such a control model incorporating a coordinated ramp metering mechanism is proposed in this study. The nonlinear state equations representing the traffic system dynamics are derived from the conservation law in difference equations form. The control model is obtained by a feedback linearization approach, so that the target density of the controller is chosen as the critical density of the traffic system. Simulation based test studies have been done in a VISSIM simulation environment in order to compare the data obtained by the shock wave modified feedback linearization method to the non-modified type, with respect to the uncontrolled system performance. Test results show that the main-link flow performance is increased sufficiently by the proposed control model.

Traditional signal control systems use prestored timing plans that have been developed offline using historic data. These systems are not responsive to dynamical demand changes of traffic and may deteriorate in performance over time. Dynamic traffic signal control systems can adapt to actual traffic conditions, coping with complex flow patterns and unpredictable variations. They seek continuous optimal system performance. The main goal of this paper is to design a methodology for control of arterial traffic flows. To fulfill this goal, the nonlinear coupled oscillators model is adapted to the traffic signal system of a two-way arterial road. The control methodology is based on measurements of the microscopic occupancy parameters for incoming flows at intersections that have a four-way geometrical structure with four-green splits. The desired signal parameters such as cycle times, green splits, and offsets are adjusted dynamically according to local traffic data. Thus, the desired signal patterns are self-organized through the mutual interactions among the signals. The numerical and case study simulation results demonstrate the effectiveness of the control methodology under the dynamical demand changes of traffic. Key words: traffic control, control systems, nonlinear coupled oscillators, signal control.

The Fuzzy Logic Signal Controller for 4-leg intersection, representing the urban road network is designed for this study. The input information of Fuzzy Signal Controller for each approaches in the intersection are the average saturation degree of flow that evaluated from microscopic flow data of the through. The microscopic flow data are measured by detectors located on the middle of the lines. These data are the information of green times for each signal plan. This controller evaluates the average saturation degree of each flow on the legs then calculates and decides the next green times after the previous green times for each cycle. After that signal times become more familiar with the dynamic of intersection flows. Finally, the performance developments by new Fuzzy Signal Controller are tested with VISSIM simulation space at the 4-leg intersection. Test results shows that there is an improvement about capacity usage and average delay times, when it is compared with the fixed time signal control systems.

The steadily increasing traffic jam on urban freeways have led to the use of several control mechanisms. Basically, these are formed by using ramp metering and variable speed control actions. In the variable speed control, the control mechanism is maintained by limiting the free flow speed of the vehicles between the specified freeway sections. The first and second Bosphorus Bridge Crossing are playing an important role in the city traffic of Istanbul. The first and second Bosphorus Bridge Crossing are very congested peak hours of day. The traffic jam may be reduced by variable speed control actions. To alleviate the jam due the lane drops in upstream flow on the first Bosphorus Bridge during the evening peak, the simulation based tests are applied. The result of these test shows that the delay per vehicle and the stops per vehicle on the first Bosphorus Bridge are decreased satisfactorily, but there is little bit change in the capacity usage.

Some type of electromechanical actuator related driving systems, such as stepper motor driving systems, have various types of implementations in the mechatronic systems. Besides the implementation variety, rapid changes in the actuator and driver technologies make it a costly and difficult task training about the type of mechatronic systems. It is most acute for undergraduate programs, specially. However, with the introduction of computers and flexible programming techniques, it is now possible to simulate these systems easily. Systems can also be emulated economically, in this way. Therefore, electromechanical actuator related mechatronic systems could be leached and/or trained, by computer simulations and/or emulations. This paper describes such a teaching and training tool study on stepper motor driving systems, including full-step, half-step and micro-step driving implementations. System emulations are fulfilled by using a microcontroller based system interface in the study.