Design and Implementation of an Elevator System for Four
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Transcript of Design and Implementation of an Elevator System for Four
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Design and Implementation of an Elevator System for Four-Floor BuildingsPrepared by: NguyenThi Hoang Vy, Nguyen Ngoc Khanh Hang, Nguyen Khoa
06ECE, Electronic and Communication Department, Danang University of Technology
Instructor: M.E. Nguyen TheNghiaElectronic and Communication Department, Danang University of Technology
AbstractElevators are considered as important transportation systems for urban communities. Elevators are
installed with onboard controllers (circuit boards) and these controllers can generate a large of signals and
events. In this paper, we propose the way to design and implement the elevator for four-floor buildings.The paper first explains our approach to design the elevator. The paper then describes our system, which
consists of a central server (PIC Microcontrollers), an optical sensor algorithm for elevator door safety,keypad algorithm for choosing the floor, supply power and motor terminals and a display function withinforming what floor we choose. The paper also present the results of complete procedure in which all the
users need to do is to stand in front of the elevator on any floor, to press a button to call it. When it comes,
they enter the elevator and then press another number to choose the floor they want.Keywords: elevator, design and implementation, PIC Microcontrollers, optical sensor, system, algorithm.
1. Introduction
Today's urban life cannot be imagined without elevators. The progressive price increase in the urbancenters of the larger cities makes the necessary intensive ground exploitation by means of the construction
of high buildings. Today the installation of synchronized elevator groups in professional use buildings(offices, hospitals or hotels) is a usual practice. Elevator is vertical transport equipment that efficiently
moves people or goods between floors of a building, vessel or other structure.The elevator system research is quite recent and has followed the technology development. The late
eighties and the nineties decade can be considered as the start point of the industrial investigation,
especially in USA and Japan ([1], [2] and [3]). After that, the research is experimented the impulse of thelargest multinational companies ([4], [5], [6] and [7]). By the end of the nineties the research in verticaltransportation was a reality and the collaborations among the private companies and the research centers
were reinforced, some examples are the Systems Analysis Laboratory in the Helsinki University ofTechnology with the KONE Corporation [8]
Therefore, the elevator system for four-floor buildings can be classified as a combinatorial optimization
problem. Due to many difficulties in analysis, design, simulation, and control, the elevator problem hasbeen studied for a long time. The more general problem assumes the following hypothesis in the elevatorsystem performance. Each hall call is attended by only one cabin. The maximum number of passengers
being transported in the cabin is bounded by its capacity. The lifts can stop at a floor only if it is exists a
hall call or a cabin call in that floor. The cabin calls are sequentially served in accordance with the lift tripdirection. A lift carrying passengers cannot change the trip direction.In this article we propose a simplified elevator system, using PIC Microcontrollers. A PIC
microcontroller is a processor with built in memory and RAM and it can be used to control this elevatorsystem projects. So it saves ourbuilding a circuit that has separate external RAM, ROM and peripheral
chips.Elevators system are generally powered by electric motors that either drive traction cables or
counterweight systems like a hoist, or pump hydraulic fluid to raise a cylindrical piston like a jack..Instead of stepping tired on staircase, people just need stand in front of the elevator, choose the floor theywant and the elevator will carry them to that floor. Besides, the interrupt algorithm assigns the hall call to
the nearest lift in the adequate trip direction.
The rest of the paper follows with the second section dealing with describing the structure and theoperation of elevator model. The third section states overallalgorithms to design the complete elevator for
four-floor buildings. The fourth section shows the main results of the implementation and the evaluationof the procedures in which comparing between our optimal design and other traditional elevators. Finally,
we highlight the main conclusions in the final section
2.Elevator system
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2.1.General structureIn this section, the general structure of elevator will be discussed with two hall call (up, down) buttons on
a oor as shown in Figure 1.
Figure 1. Structure of elevator
1.Hoister 2. Centrifugal speed limitation 3.Auxiliary cable 4.Cabin 5. Vertical cable 6. Staircase pit7. Counterweight 8. Counterweight buffer 9. Slipper 10. Lifting cable 11. Machine room
2.2.Elevator operationIn this part, the general operation of the elevator will be discussion. To understand this system,
consider an example of the elevator group control process.1) A passenger who is going to the fourth oor from the second oor presses the up hall call
button.2) The hall call signal is transmitted to the sensor.
3) The sensor sends a message to the selected floor.4) The elevator moves to the second oor and the passenger boards.
5) The passenger presses the car call button for the fourth oor.6) The elevator moves to the fourth oor.
7) The elevator arrives at the fourth oor and the passenger leaves.The core part of this section describes how the elevator system operates from starting to the end
of process.2.2.1.Reset cabin when close the power source: Move the cabin to the 1st floor despite of theposition or status of the elevator.
2.2.2.Principle of moving the cabin up/down and open/close door-Cabin moves only when the door closed.
-Doors open only when the cabin stops at the right floor.-Doors always open when the elevator is idle.
2.2.3.Floor detection: use sensor at each floor to determine the current floor of the elevator.When cabin stops at one floor, sensor will receive signal at that floor and send to the center
processor.2.2.4.Elevator usage:
2.2.4.1. Calling from outside of the elevator
Each floor has Hall Call Panel includes:+ Press button: one for going up one for going down. However, the bottom or top
floor just has one button.
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+ Led: use to show the current floor and direction of the cabin. When passengers wantto call the elevator, they just need to press button, Led will light to indicate the system receivethe command.
2.2.4.2. Calling from inside of the elevator:Inside the elevator, there is Car Operation Panel includes the following buttons:
Figure 2.CarOperation Panel
-Number button: represent for floor that elevator serve
-Alarm button : use to communicate to the outside of the elevator in some emergency cases such as
fire or power off.
3. Designing the Elevator systemIn Figure 2, the elevator is constructed to use for four-floor of building. This system consists of
the center processing, power, keypad, display, sensor and motor part. The control strategy(Center block) and the hall call assignment (Keypad block) are the most important parts and have
the most effect on the performance of this system.
Figure 3. Overview the system
3.1. Keypad Subsystem the keypad subsystem composed from many switches and was
divided two kinds:
-Hall call panel: includes two kinds of button, one for go up and one for go down. The secondand the third floor have both of these buttons. However, the first and fourth floors have only onebutton.
-Car operating panel: also includes two kinds of button, one is the number from 1 to 4represented for the floor that the elevator serve and one is the warning button which used to
communicate with the outside when having fire.
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3.2.Sensor Subsystem the sensor used in this system is optical sensor.
Figure 4. Infrared sensor
Transmitter circuit: contains one resister in series with one infrared LED. This LED used totransmit the current floor signal and was installed at each floor.
Receiver circuit: when received light form the infrared LED, the transistor conducts and makes
high voltage at port2 of OPAMP. Thus the OPAMP will be at negative saturation (V-> V+),output V0 = 0. When have something pass through, the transistor no longer conducts and makeszero voltage at port2 of OPAMP. The OPAMP now will be at positive saturation (V+> V-),
output = Vcc = 5V. In this case, PIC will receive signal and process.
3.3.Power subsystemThe power supply subsystem will provide the following voltages at the
specified current levels to the internal logic.3.4.Center Processing Subsystem- the center processing subsystem provides the logic and
control algorithm to execute the movement of the elevator.The movement will be implemented by opening a window for the following input
Number of floorDirection
Up DownThe elevator will receive this value and move to exact number of that Floor. The elevator will
have the ability to determine the priority command received from different Floors.
3.4. Display Subsystem- we use single LED to display the status of the elevator and LED
7segments to display the number of floor.-Single LED: Red for going down and warning and Green for going up
-LED 7segment: we can wire 7 legs of LED 7segments direct to 7 legs of any port in PIC.However, to save port and simply the program, we used IC 74 LS47.
3.5.Motor Subsystem- elevator contains two kinds of motor:-Door motor: use voltage at 5V. This motor reverses direction to open and close door.
-Cabin motor: use voltage at 12V. This motor reverses direction to move up and down.
4. Experimental Results and Evaluation4.1.Experimental resultsIn demo environment, the real hardware elevator for four-floor buildings has operated as following:First of all, the users press the RESET button on the board to start the system. When the system is on,they can press any calling-stage buttons which were marked by as up and down arrows in order to startthe motor. The motor will run and move the elevator cabin up/down depend on which button the users
pressed.
After moving to any stage as ordered, the second motor on the cabin will be activated and run so that thecabin gate will quickly open and close in 2 second.
1k
1k
5V
LED
5V
1k
-
+3
2
1
8
4
470
R
Port E
Q6
PHOTO NPN
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Press some calling-stage buttons at one time to see how the cabin moving. The cabin will come to each
stage by exact order as we pressed. If the cabin is going up, it will stop at each stage in order 1-2-3-4 bypriority. If the cabin is going down, it will stop at each stage in order 4-3-2-1 by priority.
The 7-segments LEDs will display the current position of the elevator cabin. When we press RESETbutton, it will display number 1. The cabin now should be placed at stage 1.
There are 5 buttons on the circuit board which were marked by 1, 2, 3, 4, X. These buttons are used for
calling exact stage we want the cabin move to. The button X is a WARNING button. If the button ispressed, the cabin will move down and stop at every stage until it reaches the first stage and stop.There are two LEDs attached on each stage to display the direction of the elevator. If the elevator is goingup, the Green LED will be shining. If the elevator is going down, the Red Led will be shining. If the
elevator stands still, both LEDs will stop shining.
We have performed numerous experiments to test the performance of the system and will show someexperimental results in the following.
Input
Press up
button at
floor3
At floor3,
press
button1
Press
button at
floor 4
first, then
press atfloor2
At floor 4,
press
button 1
first, then
button 3
While
cabin
moved
down,
press upbutton at
floor2
When
cabin is
moving to
floor3,
presswarning
button
When
elevator is
at warning
status,
press downbutton at
floor 4
Output
Move to
floor 3
GreenLED light
Move to
floor 1
Red LEDlight
Stop at
floor 2
first thenmove to
floor 4Green
LED light
Stop at
floor 3
first thenmove to
floor1Red LED
light.
The
elevator
move tofloor 1 and
then comeback to
floor 2
The cabin
move
down tofloor1
Red LEDlight
The cabin
still move
down anddoes not
execute thecommand
from floor
4
4.2.Overall performance evaluation:Building a model that has a high stable operation, and comparing the model input-output transformations
to corresponding input-output transformations for the real system can be seen in demo environment.Important similarities of the design elevatorwith real elevator systems have been observed by the users:Both are found to show almost the same performance (speed) when driven with simple policies. They
exhibit a characteristic instability, commonly called bunching in case of elevators.In the following we will consider input-output transformations more detailed. The model is described by
the function:
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Figure 5. Elevator control diagram
However, this design system just operates under some limitation:The voltage of devices:Pic: 5VMotor driver: 5VMotor: 20V
Sensor: 0.5VLEDs: 2V
5. ConclusionNowadays, elevator is an important device, especially in high buildings because it helps people save time
and labor. Therefore, in this paper, we describe the development of an elevator for four-floor buildings.
Our integrated system includes a central server (PIC Microcontrollers), an optical sensor algorithm forelevator door safety, keypad algorithm for choosing the floor, supply power and motor terminals and adisplay function with informing what floor we choose. The control strategy (Center block) and the hall
call assignment (Keypad block) are the most important parts and have the most effect on the performance
of this system.In the hall call assignment part, the hall calls are assigned to the suitable elevators to
service passengers. According to the demo, the performance of evaluation criteriawill be increased whenwe use a high importancedegree for thesespecial criteria (cable, material of cabin, frame). By the demoresult, it is noted that the overall performance of the elevator is increased in all time periods. The
prototype system is currently being tested for future commercial release by our industry collaborator.
References[1] MacDonald, C. Robert and E. Abrego. Coincident call optimization in a elevator dispatching system,Westinghouse Electric Corp. U.S. Patent No. 4 782 921, 1988.[2] Barkand, T.D.; US Dept. of Labor Mine Safety, Pittsburgh, PA , Safe electrical design of mine
elevator control systems, in Proceedings of Power Electronics Specialists Conference, IEEE, page 820-825, 2007.
[3] Thangavelu and Kandasamy. "Artificial intelligence", based learning system predicting "peak-period"
times for elevator dispatching, Otis Elevator Company, U.S. Patent No. 5 241 142,1993.
[4] Kameli, N. and Nader. Floor population detection for an elevator system, Otis Elevator Company.U.S.Patent No. 5 511 635,1996.
[5] J. B. Lee, A study on the development of optimal model for determining congurations of the
elevator systems, M.S. thesis, Hanyang Univ,1988.[6] R. D. Peters, The theory and practice of general analysis lift calculations, in Elevcon Proc., 1992,
pp. 197206.
[7] Siikonen, M-L.. Elevator group control with artificial intelligence, Helsinki University ofTechnology, Systems Analysis Laboratory, Research Reports A67 (1997).