Design & Manufacturing an Inclined Elevator

cuckootrainMechanics

Oct 31, 2013 (3 years and 5 months ago)

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Design & Manufacturing an Inclined
Elevator

Ali Hussain



200000240

Mohammed Obaid

200000297

Habib Al
-
Saffar


200000318

United Arab Emirates University

College of Engineering

Project Advisor : Prof. Kamal Moustafa

Second Semester 2005/2006

Outline


Introduction


Objectives


Mechanical system


Control system


Results and discussion


Conclusion

Introduction


An elevator is a transporting device used to move
goods or people vertically, horizontally or inclined.



Inclined elevators are used in such places that can
not use vertical space or used by disabled persons
that can not use an escalator.



Objectives


GPI


Carrying out complete dynamic force analysis.


Applying engineering sciences.


Designing elevator components such as brakes,
roping system, buffers … etc.



GPII


Selecting proper components according to the
design analysis.


Building a prototype with control devices.

Inclined Elevator

Project

Mechanical

System

Control

System

Mechanical System


Counterweight


Selection of suspension
rope


Traction drive


Elevator machine





Car


Door


Guiding rails



Real Design Layout

Scaling


Scaling can be defined as the determination of the
interdependency of variables in a physical system.



Advantage


Used in solving cost effective problems.



A model was made with same geometric,
kinematics and dynamic similarities as the real
design.



The selected scaling factor was
1000:88
.




2D AutoCAD drawings

Cont.

Cont. (Cabin)

Cabin mass= 1.13 Kg

Cont. (Counter
-
weight)

3D AutoCAD drawing

Prototype pictures

Motor recalculation



Control System


Objectives:


Controlling DC motor (Up, Down).


Controlling motor acceleration & deceleration.


Controlling level stops.


Operating system accessories (fan, light and
door
-
lock).



Closed
-
loop control diagram

Sensor


Rotary optical encoder


It is a digital electronic device used to convert
the angular position of a shaft to a number of
pulses
.



256 pulses
.




The input voltage is 5 volts.

Cont.

Coupling

Sensor

Control

device


Microcontroller unit (MCU):


Defined as a computer on a chip which is used to
control electronic devices.



Advantages:


A microcontroller unit can be a powerful tool when
building electro
-
mechanical systems.



It interacts with both hardware and user.

Atmega
8
(MCU
(


8
-
Kbyte self
-
programming Flash.


Two timers.


28
Input and Output Pins.


Input voltage between
4.5
to
5.5
V.


Output current is equal to
40
mA.


Operating at
4
MHz frequency.





Atmega
8
(MCU
(

Pins Diagram

Actuator


Motor speed control:


A PWM technique works by making a
pulsating DC square wave with a variable on
-
to
-
off ratio.


Duty cycle


The duty cycle of the pulses exiting the
MCU was calculated as following:

Motor direction controller

How does a motor turn in two directions ?


By two ways:


1)
Manually.

2)
Automatically by a computer or a
microprocessor.


Bipolar junction circuit


H
-
bridge technique has four switching elements at
its corners and the motor forms the cross bar.

Cont.

Relay H
-
Bridge

Relay operation


A
current flows through the coil, the resulting
magnetic field attracts the armature.


The movement either makes or breaks a
connection with a fixed contact.


When the current to the coil is switched off, the
armature is returned to the first position.


At the switching off action, the collapsing
magnetic field will generate a spike of current that
could damage the rest of the circuit.



Single Pole Double Throw (SPDT)


Used to reduce the number of relays from four to
two.


Two relays with
20
A current each were used.




Circuit components

Opto
-
coupler


An opto
-
coupler is an optical link and it connects two
circuits via this link.


Used as insulation and a switch for any circuit.




Cont.

Transistor array



Used to increase the current level in order to
operate the relays (amplifier).



MOSFET power transistor


Supplies 110 A current to the motor.


Cont.

Crystal filter


It provides a very exactly defined centre frequency which
leads to stabilize the input frequency.


Supply frequency equals to
4
MHz.



Voltage regulator


Automatically maintains a constant voltage level


Supplies
5
V after changing it from
12
V.

Cont.

And Gate



A logic gate is an arrangement
of controlled switches used to
calculate operations in digital
circuits.


It is a multiplication operation
between the three input
variables (A,B and D).

Input
1

Input 2

Input 3

Output

0

0

0

0

0

0

1

0

0

1

0

0

0

1

1

0

1

0

0

0

1

0

1

0

1

1

0

0

1

1

1

1

Cont.

Diode


It allows an electrical current to flow in one
direction.


Seven
-
segment display


A method of displaying decimal numeric feedback
on the internal operations of devices.


Printed circuit board (PCB)


Used to mechanically support and electrically
connect electronic components using conductive
pathways made from copper sheets on a non
-
coductive material.



PCBs are inexpensive, fast, and consistent in high
volume production.

Power supplying and direction schematic


Power supplying and direction circuit



MCU schematic


MCU circuit



Complete control system circuit


BASIC

COMPILER

Cont

Cont

Results & Discussion





Cycle period:

Cont.

Acceleration operation

Cont.


The obtained frequency from the oscilloscope was
equal to 1.9 KHz.




The percentage error between the theoretical and
experimental values was equal to 5%.

Cont.


The velocity of the cabin was measured
experimentally after the acceleration and before
the deceleration operation periods
.

Cont.


The percentage error of velocity was equal to
13
%.



This error was formed by two factors;


The slip between the rope and the sheave
groove.


Random error.

Conclusion


All objectives of the project were met.


Modifying the project can be done by two ways:


Adding limit
-
switch at each floor.


Enhancing the sheave contact area with the
rope (V
-
groove).