Microcomputer principle traffic light control system 20

Design tasks and requirements: II. Scheme comparison and evaluation demonstration:

Traffic light control:1 Control the LED LED light emitting diode through the 8255A parallel port. 2 Port A controls the red light, Port B controls the yellow light, and Port C controls the green light.

3 If the output is 0, it will be on, and if the output is 1, it will be off. 4 Use the 8253 timing to control the transformation time. Requirements:

There is an intersection in the south direction, the north direction is east-west, and the initial state is 4 intersections with all red lights. After that, the green light at the intersection is on, the red light at the intersection is on, and the intersection direction is open to traffic. After a delay of 30 seconds, the green light at the intersection goes out, while the yellow light at the intersection 1,3 starts flashing (1Hz).

After flashing 5 times, the red light at the intersection is on, and at the same time, the green light at the intersection is on and the intersection direction starts to open to traffic. After a delay of 30 seconds, the green light at the intersection goes out and the yellow light starts flashing. After flashing 5 times, switch to the direction of the junction.

After that, repeat the above process. 2. Scheme comparison and evaluation demonstration: Analysis of the topic, red, yellow, green lights can be connected to the 8255 A port, B port and C port respectively, the light can be directly controlled by the 8086 output 0,1, 30 seconds delay and flashing by 8253.

Scheme content: The frequency of the yellow light flashing is 1hz, so think of a 1hz square wave generated by the 8253, the 8255 controls or the time when the door opens, and the 8253 will input the square wave signal or the door to make the yellow light flash. Because the maximum counting value is 65535, the value of 1MHz 65536 is much greater than 2Hz, so the way of cascading two counters is adopted, and the clock0 of 8253 channel 0 input is the 1MHz clock pulse generated by the divider, which works in mode 3, that is, the square wave generator mode, and the theoretical design output period is the square wave.

The repetition period of the clock pulse of 1MHz is t=1 1MHz=1 s, so the initial count of channel 0 is 10000=2710h. Therefore, the square wave is used as the input clock pulse of clock1 and clock2 respectively, so the input clock frequency of channel 1 and channel 2 is 100Hz, channel 1 works as a counter in mode 1, the initial value of counting is 3000=BB8H is 30s, and when the count is reached, a high level is output to the PA7 port of 8255, 8255 inputs the data of port A to 8086, and 8086 detects that the high level completes the 30s timing. Channel 2 works in mode 3 and needs to output a 1Hz square wave, through an OR gate and 8086 to jointly control the flashing of the yellow light, so it also works in the square wave generator mode, its initial counting value is 100=64h, the state of the yellow light is fed back to the port PB7 and PC7 of 8055, and the same input is to 8086, 8086 can know the state change of the yellow light by detecting the port state twice, and the state change of 9 times can complete 5 flashes.

The gating signal of the three channels is not used, and all of them can be connected to 5V.

I had forgotten about a course design in my junior year.

1. Set the traffic light signal control parameters at each intersection so that the signal control of the traffic flow in the direction of all parties at the intersection is the least delayed.

2. In the case of interlocking green wave control at multiple intersections, the above conditions are sought to be met, and the formation of two-way green wave band is ensured, and the green wave bandwidth reaches the widest.

3. Xiaoye establishes a time-sharing model of traffic flow, such as the division of daily periods, and establishes the flow matrix of each daily period.

4. Solve the optimal timing scheme table for each period.

5. Set the controller parameters according to the timing table, and ensure that it operates normally on time.

6. Seasonally reconstruct the flow model and re-solve the parameters for optimization.

Abstract:With the increase of vehicles, the traditional traffic signal Meng file mountain lamp is more and more incapable of managing traffic, so there is the invention of intelligent traffic lights, which is the product of the combination of Internet of Things technology, artificial intelligence technology and big data collection and mining technology, which can control traffic signals according to the road conditions using timing control, induction control and adaptive control. The intelligent traffic light is very intelligent, it has the function of road network linkage monitoring, vehicle information recognition, and reasonable emergency fault tolerance scheme.

Let's take a look at intelligent traffic lights. 1. How to control traffic signals in the intelligent traffic light control system.

With the development of the economic level, traffic congestion has become a major problem in urban supervision, under the requirements of building a smart city and the development of Internet of Things technology, intelligent traffic lights as an intelligent product of traditional traffic lights, gradually applied to improve traffic conditions. There are three main control methods of intelligent traffic lights:

1. Timing control.

The control system of the intelligent traffic light operates according to the pre-set timing scheme, which can only use one timing scheme a day, and also adopts several timing schemes according to the traffic volume in different periods.

2. Induction control.

A vehicle detector is set on the entrance road of the intersection, and the traffic signal timing scheme is calculated by a computer or an intelligent signal controller, which can be changed at any time with the traffic flow information detected by the detector.

3. Adaptive control.

This intelligent traffic light can continuously measure the state of the traffic system, including the traffic flow, the number of stops, the delay time, the length of the queue, etc., and use the difference to change the adjustable parameters of the system or produce a control to make the traffic control effect better.

Second, are smart traffic lights really smart?

Intelligent traffic lights are a successful solution in the intelligent transportation industry, its core is a fully intelligent traffic integrated management and control platform system, which can collect and analyze road data to develop a traffic light timing scheme, which is relatively intelligent. The intelligence of intelligent traffic lights is reflected in three aspects:

1. Road network linkage monitoring intelligence.

The smart traffic light adopts a traffic optimization algorithm based on dynamic data and machine deep learning, which can ensure that the design timing of each cycle is based on the optimal scheme under the current information, and the algorithm can take into account the interaction between the timing schemes of each intersection, and has the concept of overall thinking to reduce the overall delay time of the entire optimized area in the direction of optimization.

2. Intelligent vehicle information recognition.

Intelligent traffic lights can identify vehicle information by themselves, adjust the priority weight of roads for special vehicles such as police cars and fire trucks, so as to optimize the traffic signal timing scheme in real time and promote the improvement of road utilization.

3. Intelligent emergency fault tolerance scheme.

When there is a situation other than the lack of input data, the intelligent traffic light will generate a sub-optimal timing scheme based on historical data, and synchronously check the fault, which has a good ability to tolerate stupid errors.

System design has a complete program.

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