Transcript WIRELESS CONTROLLER FOR DC MOTOR

By:
Supervisor:
Khalid Hawari
Dr. Jamal Kharousheh
Muath Nijim
Dr. Nasser Hamad
Thaer shaikh Ibrahim
27 December 2010
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Introduction
Applications
Block Diagram
Full Schematic
Hardware Layout and Design Specs
User Interface
Tests
Challenges
Successes
Results
Next Step
Motivation:
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Wireless becoming more and more available and
widely used.
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Wireless control technology is effective in the world.
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It is general project so it is can be installed for any
devices in many places.
Features:
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Wireless Controller for DC Motor
Offset QPSK Wireless Standard
Windows based GUI
12 V DC Motor
Battery powered
Variable speed
Benefits:
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Practical
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Provides Flexibility
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Economical
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User-friendly
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Can be ran from any PC running Windows
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Robotics
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Remote control car
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Industrial Uses
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Household Uses
Microcontroller:
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PIC16F877 40 pin.
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1 kHz internal clock used for timers.
Programmed in PIC C using PIC C Compiler.
Receives control signal from user software.
Translates desired speed to necessary duty
cycle.
Sends duty cycle to H-bridge inputs using
onboard PWMs.
H-Bridge:
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L298N Dual H-Bridge Driver.
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Motor direction can be controlled.
Duty cycle determines speed by controlling
how long switches are active.
IN1 and IN2 fed from PWM.
Adjusted voltage is output to motor
terminals.
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GUI developed in Visual C-sharp.
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It can detect the active port automatically.
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User can accelerate, decelerate, start and stop
motor.
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Motor direction can be chosen.
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Speed is output to serial port (RS232) by
software.
Functional Tests:
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Used HyperTerminal to get initial connection
between XBee Modules and another XBee with
their implemented receiver and transmitter
circuits.
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Sent serial input to PIC, tested basic outputs
(oscilloscope, serial text echo).
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Tested H-Bridge using function generator.
Operation Tests:
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For a given duty cycle, the resulting speed was
measured.
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Using a collection of these points, a linear
translation from duty cycle to speed was
calculated.
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At 10 RPM: Duty cycle = 110
At 120 RPM: Duty cycle = 950
Y = mx + b  Duty = 7.93(speed) + 30.87
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Replaced Voltage Divider consisting of resistors
with Voltage Regulators.
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H-Bridge suffer from little maximum current.
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ASCII Translation Issues.
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Motor ran in both directions.
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0-120 RPM range.
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Maximum continuous load = 30 W
Motor Operations:
No-Load Motor Current vs. Terminal Voltage
no load output voltage Vs input
current
1.8
1.6
1.2
1
0.8
0.6
0.4
0.2
0
14
12
10
8
6
output voltage
4
2
0
input current
1.4
Motor Operations
Max Load Motor Current vs. Terminal Voltage
With load output voltage Vs input current
1.6
1.4
1
0.8
0.6
0.4
0.2
0
12
10
8
6
output voltage
4
2
0
input current
1.2
Duty Cycle to H-Bridge:
PIC To H-Bridge Control Signal
@ 42 RPM
PIC To H-Bridge Control Signal
@ 90 RPM
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Designed feedback loop for closed system
control.
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Designed optical encoder wheel on motor shaft
with one notch to read RPM.
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Directed signal to PIC, began programming.
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Install the system in a practical application as a
car control.
Modified the interface program to display the real
and active RPM.