DOODLE DRIVE Presenter: Peachanok Lertkajornkitti Team 6 Reliability and Safety Analysis

PROJECT OVERVIEW  Android application as controller  Robot vehicle with microcontroller  Path will be drawn in Android application and the vehicle will follow that path  Outdoor mode with GPS, Google Maps, 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 = 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 ModePossible CauseFailure EffectsCriticality PWM Signal FailurePWM pins failure Servo and H-Bridge will not work Vehicle unable to move Unable to swing the ultrasonic sensors Low UART Signal FailureUART pins failure No GPS and Bluetooth communication. Low I2C Signal FailureI2C pins failure Compass failureLow GPIO Signal FailureGPIO pins failure Ultrasonic sensors failure Fuel Gauge failure Low - Medium

FMECA  Compass Failure ModePossible CauseFailure EffectsCriticality Compass failureR1 & R2 failure (Pulled up resistors) Incorrect reading of the compass Low

FMECA  H-Bridge Failure ModePossible CauseFailure EffectsCriticality Motor driver failsD3 – D10, C10. Unpredictable behavior of the vehicle’s movement Medium - Low

FMECA  Voltage Regulators (3.3V and 5V) Failure ModePossible CauseFailure EffectsCriticality Vout = 0VL2, C4, D2, C3 Components using the 3.3V regulators will not operate. Low Vout > 3.3V Vout > 5V C4 (3.3V) or C2 (5V) Overheating of components High –cause burn when touched Vout unpredictableL2, C4, D2, C3 Unpredictable behavior of components 5V – ultrasonic sensors and servo 3.3V – compass, GPS, Bluetooth etc. Medium –unable to control 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)

H-BRIDGE

COMPASS

VOLTAGE REGULATORS