中英文对照外文翻译文献
(文档含英文原文和中文翻译)
Design of traffic light control system based on MCGS Abstract: One kind of traffic light control system using programmable logic controller (PLC), via software control traffic lights run automatically. In the system, the original line is the program instead of the relay, programmable logic controller (PLC) system hardware and software resources to be fair use. Normal operation and emergency transport for a detailed description and from the East and West emergencies can be mutually linked. Traffic signal systems and two seven-segment digital display in the countdown order; also discussed in detail the wiring of the hardware and PLC ladder. Traffic lights at the crossroads of the remote monitoring system design configuration software MCGS, real-time monitoring of traffic lights, greatly improving the reliability of data transmission. At the same time, we can configure the traffic lights to change the status of photographs.
Keywords: switching power,supply protection, circuit system design
Signal control is a necessary measure to maintain the quality and safety of traffic circulation. Further development of present signal control has great potential to reduce travel times, vehicle and accident co
sts, and vehicle emissions. The development of detection and
computer technology has changed traffic signal control from fixed-time open-loop regulation to adaptive feedback control. Present adaptive control methods, like the British MOV A, Swedish SOS (isolated signals) and British SCOOT (area-wide control), use mathematical optimization and simulation techniques to adjust the signal timing to the observed fluctuations of traffic flow in real time. The optimization is done by changing the green time and cycle lengths of the signals. In area-wide control the offsets between intersections are also changed. Several methods have been developed for determining the optimal cycle length and the minimum delay at an intersection but, based on uncertainty and rigid nature of traffic signal control, the global optimum is not possible to find out.
In adaptive traffic signal control the increase in flexibility increases the number of overlapping green phases in the cycle, thus making the mathematical optimization very complicated and difficult. For that reason, the adaptive signal control in most cases is not based on precise optimization but on the green extension principle. In practice, uniformity is the principle followed in signal control for traffic safety reasons. This sets limitations to the cycle time and phase arrangements. Hence, traffic signal control in practice are based on tailor-made solutions and adjustments made by the traffic planners. The modern programmable signal controllers with a great number of adjustable parameters are well suited to this pr
ocess. For good results, an experienced planner and fine-tuning in the field is needed. Fuzzy control has proven to be successful in problems where exact mathematical modelling is hard or impossible but an experienced human can control the process operator. Thus, traffic signal control in particular is a suitable task for fuzzy control. Indeed, one of the oldest examples of the potentials of fuzzy control is a simulation of traffic signal control in an inter-section of two one-way streets. Even in this very simple case the fuzzy control was at least as good as the traditional adaptive control. In general, fuzzy control is found to be superior in complex problems with multiobjective decisions. In traffic signal control several traffic flows compete from the same time and space, and different priorities are often set to different traffic flows or vehicle groups. In addition, the optimization includes several simultaneous criteria, like the average and maximum vehicle and pedestrian delays, maximum queue lengths and percentage of stopped vehicles. So, it is very likely that fuzzy
control is very competitive in complicated real intersections where the use of traditional optimization methods is problematic.
Fuzzy logic has been introduced and successfully applied to a wide range of automatic control tasks. The main benefit of fuzzy logic is the opportunity to model the ambiguity and the uncertainty of decision-making. Moreover, fuzzy logic has the ability to comprehend linguistic instructions and to gen
erate control strategies based on priori communication. The point in utilizing fuzzy logic in control theory is to model control based on human expert knowledge, rather than to model the process itself. Indeed, fuzzy control has proven to be successful in problems where exact mathematical modelling is hard or impossible but an experienced human operator can control process. In general, fuzzy control is found to be superior in complex problems with multi-objective decisions.
At present, there is a multitude of inference systems based on fuzzy technique. Most of them, however, suffer ill-defined foundations; even if they are mostly performing better that classical mathematical method, they still contain black boxes, e.g. de fuzzification, which are very difficult to justify mathematically or logically. For example, fuzzy IF - THEN rules, which are in the core of fuzzy inference systems, are often reported to be generalizations of classical Modus Ponens rule of inference, but literally this not the case; the relation between these rules and any known many-valued logic is complicated and artificial. Moreover, the performance of an expert system should be equivalent to that of human expert: it should give the same results that the expert gives, but warn when the control situation is so vague that an expert is not sure about the right action. The existing fuzzy expert systems very seldom fulfil this latter condition.
1. Introduction
With the social development and progress, traffic flow becomes increasingly important. On the one hand, too many crossroads, more and more vehicles, which are causing serious traffic congestion. On the other hand, in the limited time it is necessary to maintain the vehicle and pedestrian fast and safe. Therefore, one kind of traffic light control system
design, can be used to display time countdown, with computer controlled real-time data. In addition, the configuration technology for real-time images that reflect the traffic lights, understand the historical crossroads of work to get traffic lights visualization. The system consists of host computer and a low computer. MCGS configuration is installed in the host computer is lower by the PLC control system.
Normal traffic signal timing diagram shown in Figure 1. But there are some urgent matters, for example. There are a number of ambulances to transport patients to the hospital or to deal with a number of fire engines and fire. Fire engines and ambulances rushed to take precedence over other traffic scene. According to urban traffic control system, under normal circumstances, two control methods and urgency traffic control factors into account. This process can show 14 segment encoder. U.S. traffic lights instant record of the monitoring process.
Emergency control signals to control traffic emergency switch. If there is no emergency lights all work,
but when an emergency open. In this case, the car is urgent priority pass. Once the emergency vehicle passes, emergency switch off immediately. The green light in the same direction of the vehicle quickly flashes three times, followed by the normal operation. If you were from the north-south and east-west two emergency vehicles, traffic control systems can respond quickly came early, and then another.
2. Traffic Control System Design
A. Hardware design
CP1H series PLC as controller, display the procedure should stop when the time series of abnormal system operation, the time will not be displayed. When the emergency procedures are completed time series, countdown display program should be reset. At 220 V AC system is used to control traffic lights, 24 V DC control segment encoder, Figure 2 shows the scheme Eastern time display. CP1H series programmable logic controller (PLC) is a simple controller, which consists of 24 inputs and sixteen outputs. Because the output to twenty In this system, an I / O module must be extended. Circuit is shown in Figure 2.
B. Control Program Design
Six timers and two special normal open pulse is used in this system, the green light flashes for all north-south and east-timer and a special pulse; eight kinds of interlockingcontroller翻译中文

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。