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

θ

a

Sheave

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)

Kg.

.).(.

riderkgX

kgXm

mm

mperkg

032

131450450

htcabin weig load rated of 45% mass weight -Counter

/5.0

)(Prototype )(4

085.0085.0

(Real) 29.080

2

2

3D AutoCAD drawing

Prototype pictures

Motor recalculation

scmV

sV

RVR

V

measuredrpm

cmR

th

th

th

/2.20

60

211075.1

)(110motorwiper

75.1

2

2

2

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.

Atmega8 (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.

Atmega8 (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:

scycleuty

scycleuty

cycleuty

s

768D

2563D

PulsesNo. increment Timer D

312/4000000

1000increment Timer

crystal in the increments of No.speed Crystal

t increment Timer

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 20A 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:

%35100256

90256

powerpersentageMinimum

KHzsperiodCycle

Frequency

speriodCycle

sscycledutyof

003.22.499

11

2.4998.268768

8.26835.0768%35

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.

scmv

v

t

/ 5.176.1

28

t

x

cm 28 x

s 1.6

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).