Graduation Design (Thesis) Opening Report

First, the purpose and significance of the topic:

In modern society, elevators have become an indispensable means of transportation. The existence of elevators makes the transportation of each tall building more convenient. The development of elevator control technology has mainly gone through three stages: relay control stage, microcomputer control stage and field bus control stage. At present, the elevator design adopts PLC, which requires flexible function change, simple programming, less faults and low noise. Convenient maintenance, energy saving and labor saving, strong anti-interference ability and small control box area. When passengers enter the elevator, press the floor button and the elevator door will close automatically. The control system carries out the following operations: according to the position of the car and the number of floors where passengers are located, determine the running direction of the car to ensure that the car slows down when lying flat. Park the car on the selected floor; At the same time, according to the call of the floor, stop halfway and automatically open and close the door. In addition, there should be signal lights inside and outside the car to show the running direction of the elevator and the number of floors. With the rapid development of economy, microelectronics technology, computer technology and automatic control technology have also developed rapidly. AC variable frequency speed regulation technology has entered a new era, and its application is more and more extensive. Elevator is a vertical means of transportation in modern high-rise buildings, and its design requires stability, safety and high quality. With the continuous improvement of people's living standards, the requirements for elevators have also increased accordingly, and elevators have developed rapidly. At present, the general development trend of elevators is mainly reflected in the following aspects.

First, the elevator drive technology

(1) AC variable frequency speed control technology has been widely developed and applied, and its control type has gradually developed from GTR to GTR and IGBT, which makes its control performance more perfect and improved.

(2) The elevator is driven by linear motor, which fundamentally breaks through the elevator driving mode.

Second, the high-speed elevator with DC SCR gearless drive control system is gradually developing to VVVF gearless drive control system, because the latter has the characteristics and advantages of energy saving and system miniaturization. Elevator control technology

The application of (1) microcomputer network control technology makes the system more reliable and the function processing more flexible.

(2) Surface mount technology and large-scale ASIC circuits are adopted to reduce the printed board area and improve the reliability of electronic circuits.

(3) Fuzzy logic and expert system are applied to the distribution of elevator group control system, which improves the efficiency and accuracy of the group control system.

(4) The intelligent power module is used to form the elevator intelligent control system.

(5) Using high-digit CPU to enhance the elevator signal processing function and speed up the signal processing.

(6) Constantly increase and expand various selection functions of elevators. At present, there are more than 60 to 70 kinds of elevator functions available, which constitute the diversification, artistry and personalization of elevator car modeling tone, and are in harmony with the building.

Third, the elevator speed.

With the development of high-rise buildings and elevator basic technology, the running speed of elevators is gradually developing to high speed. At present, the highest speed of elevators in the world has reached 12.5m/s, which was developed and put into market by Mitsubishi Corporation of Japan and put into use in Japan.

Four, the technical aspects of the traction machine

The gear traction machine is gradually developing from the traditional worm gear transmission to planetary gear rotation, which is beneficial to reduce the size of the traction machine, improve the bearing capacity and transmission efficiency, and make it develop at a high speed.

Most elevators made in China are controlled by relays and PLC. PLC is a special computer for industrial automation control, which belongs to computer control mode in essence. Like ordinary microcomputer, PLC uses general or special CPU as word processor to realize channel (word) operation and data storage, and bit processor (Boolean processor) performs point (bit) operation and control. PLC control generally has the characteristics of high reliability, easy operation, easy maintenance, simple programming and strong flexibility. This design is realized by PLC control, and the logical relationship of elevator is studied and analyzed, so as to realize control. Because of the complexity of elevator control system, we adopt four-person division of labor and modular design. The modules I want to design are main drag control and automatic door opening and closing control.