DESIGN AND IMPLEMENTATION OF ELECTRONIC LIFT

CHAPTER ONE

1.0       INTRODUCTION   

Lift is a type of vertical transport equipment that efficiently moves people or goods between floors (levels, decks) of a building, vessel or other structures. Elevators are generally powered by electric motors that either drive traction cables or counterweight s like a hoist, or pump hydraulic fluid to raise a cylindrical piston like a jack.

In agriculture and manufacturing, an elevator is any type of conveyor device used to lift materials in a continuous stream into bins or silos. Several types exist, such as the chain and bucket elevator, grain auger screw conveyor using the principle of Archimedes’ screw, or the chain and paddles/forks of hay elevators. The elevator was a key invention in the development of skyscrapers. Up to that point, it was considered that no building should be higher than 10 storeys because of the effort of climbing and descending the stairs. The elevator is also a means which reduces time to transfer the things very quickly from one stairs to another. With the population growing the need for housing is increasing with the lack of livable area, housing as increased into multi level units, thus the need for elevators. They provide access for those who are handicapped. Having an apartment on the 12th floor, walking the stairs can be a challenge, making an elevator is a bonus because you don’t have to walk up and down the stairs. It allowed the people to travel up and down the building so much easier that it allowed for taller and taller buildings to be made, which allowed more square feet of office space, business space, etc.

The elevator system is a vertical transport vehicle that efficiently moves people or goods between floors of a building. They are generally powered by electric motors. The most popular elevator is the rope elevator. In the rope elevator, the car is raised and lowered by transaction with steel rope. Elevators also have electromagnetic brakes that engage, when the car comes to a stop. The electromagnetic actually keeps the brakes in the open position. Instead of closing them with the design, the brakes will automatically clamp shut if the elevator loses power. Elevators also have Automatic braking systems near the top and the bottom of the elevator shaft.

The elevator control system is one of the most important aspects in electronics control system in automotive applications in the world today due to level of the introduction of high rising building in architectural constructions worldwide. In this investigation elevator control system is designed with different control strategies. First the elevator control system is implemented for multi-storey building with five storeys rising. This implementation is based on Fuzzy logic controller for intelligent control of elevator group system. This proposed approach is based on algorithm which is developed to reduce the amount of computation required by focusing only on relevant rules and ignoring those which are irrelevant to the condition for better performance of the group of elevator system. Here only two inputs are considered i.e. the elevator switches and number of stops. Based on these data, fuzzy controller can calculate the Performance Index (PI) of each elevator car, the car which has maximum PI gives the answer to the hall calls (Varun Dubey p.221, 2005).

The elevator control system that is implemented in this project is designed around the 8051 microcontroller unit which performs all the necessary calculations that are required for the operation of the elevator in the building that it is installed. The control also provides a seven segment display system with which the position of the lift is noticed. The project also provides a motor control system that controls the movement of the elevator up and down the building.

In the operation of the system, When a User presses an elevator button; the elevator button sensor sends the elevator button request to the system MCU (microcontroller unit) of the project, identifying the destination floor the user wishes to visit. When any new request comes, this new request is added to the list of floors to visit. If the elevator is stationary, the system determines in which direction the system should move in order to service the next request. The system commands the elevator door to close, when user presses the elevator door closed button. When the door has closed, the system commands the motor to start moving the elevator, either in up and down direction, based on switch pressed. When the elevator moves between floors, the arrival sensor detects that the elevator is approaching a floor and notifies the system to stop the elevator and open the door of the elevator system. The movement of the elevator is controlled by the motor control (Maxda.F p56, 1984).

The project implementation is achieved through the use of the 8051 microcontroller unit which is used to perform all the necessary calculations that is required for the system operation. The project also makes use of a seven segment display unit for the display of the various positions of the lift in the building. Also present, is the motor driver unit which simply controls the movement of the motor in order to lift the elevator up and down the building.

1.1       BACKGROUND OF THE STUDY

The trend to the modern types of elevators has pass through series of evolutionary changes. The first reference elevator was invented by Archimedes in 312. From some literacy source, elevators were developed as cable on a hemp rope and powered by hand or by through animals. This type of elevator was installed in the Sinai Monastery of Egypt. In the 17th century, the very small type elevators were placed in the building of England and France. In 1793, Lvan Kuliben created an elevator with the screw lifting mechanism for the winter place of Saint Petersburg. In 1816, an elevator was established in the main building of Sub-moscow village called Arkhamgelskoye. In the middle 1800’s, there was much type of curd elevators that carried freight. Most of them ran hydraulically. The first hydraulic elevators used a plunger below the car to raise or lower the elevator. A pump applied water pressure to a plunger, or steel column, inside a vertical cylinder. In 1852, Elisha Otis introduced the safety elevator, which prevented the fall of the cab, if the cable broke. In 1857 March 23rd, the first Otis passenger elevator was installed in New York City. The first Electric elevator was built by Werner Von Siemens in 1880. In 1874, J.W. Meaker patented a method which permitted elevator doors to open and close safely. In 1882, when hydraulic power was a well established technology, a company later named the London Hydraulic Power Company was formed. In 1929, Clarence Conrad Crispen, with Inclinator Company of America, created the first residential elevator (Varun Dubey p.221, 2005).

The elevator modeled in this project works with the principles of the electric motor elevators. The movement of the elevator is controlled by the movement of the electric motor that is used in the project. The control of the elevator is achieved by the use of the microcontroller unit that utilizes the principles of artificial intelligence.

1.2       AIM OF RESEARCH

The aim of this project is to design a system that will transport people and goods to different levels in a five story building. Due to technological advancements, in the world, automation of system has dominated most systems in the world utilizing the principles of artificial intelligence to enable systems behave as though they are humans and act with mimic of the human life. The concept of the elevator lift is an invention that enables the movement of people and cargo up and down a given building, enabling the movement to be facilitated with much ease. The need for such achievement is the main goal of this project. The project is aimed at implementing a reliable control system of the elevator in a given building by the use of the 8051 microcontroller unit

1.3       OBJECTIVES

The project is also designed with the following objectives;

1.     To design a lift control system by using microcontroller 8051

2.     To design the program (software) for the overall system according to the real lift traffic management algorithm

3.     To integrate the hardware and software in order to simulate the functions of a basic lift system.

4.     To build a lift model to simulate the actual system.

5.     To investigate various other existing systems and employ some improvements and modifications that makes the system more reliable.

1.4       MOTIVATION

In the recent times, the rate of construction of high rising buildings, multi-stories and sky scrapers has risen to a great extent. For this reason there is a need to provide a reliable method by which human beings and goods can be moved up and down the high rising structures. The implementation of this project is carried out with the aim of providing such system that can enable the movement of people as well as goods up and down a given structure irrespective of the height and size.

1.5       SIGNIFICANCE OF THE STUDY

The elevator was a key invention in the development of skyscrapers. Up to that point, it was considered that no building should be higher than 10 storeys because of the effort of climbing and descending the stairs. The elevator is also a means which reduces time to transfer the things very quickly from one stairs to another. With the population growing, the need for housing is increasing with the lack of livable area, housing as increased into multi level units, thus the need for elevators. They provide access for those who are handicapped. Having an apartment on the 12th floor, walking the stairs can be a challenge, making an elevator is a bonus because you don’t have to walk up and down the stairs. It allowed the people travel up and down the building so much easier that it allowed for taller and taller buildings to be made, which allowed more square feet of office space, business space, etc

1.6       SCOPE AND LIMITATIONS OF THE RESEARCH

The five storey’s elevator control system that is implemented in this project is a well reliable system that offers application for a wide range of areas including domestic buildings and industrial buildings. The project focuses its attention on the implementation of lift control for a five storeys structure. It is only actually a model that is used for the demonstration of the real time system. Thus for the proper implementation of the project, it is required that the design should be reproached for a real time application basis. The project is also limited to a number of factors and these includes;

1.     It only lays emphasis on the implementation of five storeys building structure and does not include the design for more complex building structures.

2.     The project is subject to a very high cost of installation and maintenance.

3.     The implementation of the project is quite complex to achieve.

4.     The integration of the soft ware and the hard ware is quite difficult to implement and requires an extra knowledge of the designer for its maintenance.

5.     The project is also completely dependent on power supplies and can lead to great complications if power supply failure occurs.