DOODLE DRIVE
Presenter: Peachanok Lertkajornkitti
![C:\Users\curtisa\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\DMHF5W84\MC900439789[1].png](data/images/img4.png)
Team 6
Reliability and Safety Analysis
PROJECT OVERVIEW
Android application ascontroller
Robot vehicle withmicrocontroller
Path will be drawn in Androidapplication and the vehicle willfollow that path
Outdoor mode with GPS, GoogleMaps,Compass
Indoor mode with tilt control
CRITICALITY LEVELS
Low:
Minor failures that doesn’t cause any physical damage to user
Doesn’t cause any damage to the PCB
E.g. Reading errors
Medium:
Cause physical damage to the PCB or the vehicle
E.g. Damage of the components due to overheating, inability to control the vehicle
High:
Cause injury to user/people around
E.g. Burn due to touching the components that overheats
COMPONENTS FOR ANALYSIS
Microcontroller (LPC1768)
Complex
100 pins , 32-bit
Tj = 50 ºC
λ = 2.904 e -6
MTTF: 40 years
COMPONENTS FOR ANALYSIS
Voltage Regulators (LM2596)
High temperature (but with good heat sink)
Tj = 25 ºC
λ = 1.44e -7
MTTF: 792 years
COMPONENTS FOR ANALYSIS
H-Bridge
High voltage and current
High junction temperature
Tj = 75 ºC
λ = 6.6e-7
MTTF: 171 years
COMPONENTS FOR ANALYSIS
Compass
MEMS (Micro-Electro-Mechanical Systems) –less reliable than ICs
Tj = 25 ºC
λ = 5e-7
MTTF: 228 years
BLOCK DIAGRAM
PWM
FMECA
Microcontroller
Failure Mode
Possible Cause
Failure Effects
Criticality
PWM Signal Failure
PWM pins failure
• Servo and H-Bridgewill not work
• Vehicle unable tomove
• Unable to swing theultrasonic sensors
Low
UART Signal Failure
UART pins failure
• No GPS andBluetoothcommunication.
Low
I2C Signal Failure
I2C pins failure
• Compass failure
Low
GPIO Signal Failure
GPIO pins failure
• Ultrasonic sensorsfailure
• Fuel Gauge failure
Low - Medium
FMECA
Compass
Failure Mode
Possible Cause
Failure Effects
Criticality
Compass failure
R1 & R2 failure(Pulled up resistors)
Incorrect reading ofthe compass
Low
FMECA
H-Bridge
Failure Mode
Possible Cause
Failure Effects
Criticality
Motor driver fails
D3 – D10, C10.
• Unpredictablebehavior of thevehicle’s movement
Medium - Low
FMECA
Voltage Regulators (3.3V and 5V)
Failure Mode
Possible Cause
Failure Effects
Criticality
Vout = 0V
L2, C4, D2, C3
• Components usingthe 3.3V regulatorswill not operate.
Low
Vout > 3.3V
Vout > 5V
C4 (3.3V) or C2 (5V)
• Overheating ofcomponents
High –cause burnwhen touched
Vout unpredictable
L2, C4, D2, C3
• Unpredictablebehavior ofcomponents
• 5V – ultrasonicsensors and servo
• 3.3V – compass,GPS, Bluetooth etc.
Medium –unable tocontrol the vehicle
MICROCONTROLLER
1: Compass (I2C)
2: Bluetooth (UART)
3: GPS (UART)
4: H-Bridge (PWM,GPIO)
5: Ultrasonic (GPIO)
6: Optical Encoders(Input Capture, GPIO)
7: Crystal Oscillator
8: Fuel Gauge (GPIO)
9: Servo (PWM)
1
3
7
8
2
4
9
5
6
H-BRIDGE
COMPASS
VOLTAGE REGULATORS
