1. Autonomous Rescue Vehicle (Team 10)
Safety & Reliability Presentation
By Ruiyang Lin

2. Project Overview
A robot that can detect the location of a lost person and navigate towards him/her by itself
- Location detection with a GPS receiver
- Six-wheel chassis to frugged terrain
- Communication between the lost person and the robot with RF module

3. Criticality Definition
High: system not operable (unable to find the lost person, permanent damage to the device)
Medium: unable to retrieve the device (can find the person but unable to come back)
Low: system functional but inconvenient for users (takes longer to find the lost person, battery dies half way)

4. Components selected Microcontroller: PIC32MX120F032B - Most complex IC
- Most critical component
H-bridge: TLE5206
- Under stress because of heat and switching
- Highest failure rate
Voltage Regulator: LM1117
- Temperature might get high when all components are operating

5. MOS digital microprocessor devices (Mil-Hdbk-217F)
Microcontroller:
MOS digital microprocessor devices (Mil-Hdbk-217F)
Parameter
Description
Value
Comment
Die complexity failure rate
0.56
32-bit microcontroller
Temperature factor
0.31
TJ = 125 °C
Package failure rate
0.013
28-pin SMT
Environment factor
4.0
Mobile ground environment
Quality factor 10
Commercial level
Learning factor 1
> 2 yrs in production
2.256
MTTF
50 yrs

6. Linear Gate/Logic Array (Mil-Hdbk-217F)
H-bridge:
Linear Gate/Logic Array (Mil-Hdbk-217F)
Parameter
Description
Value
Comment
Die complexity failure rate
0.01
<100 transistors
Temperature factor
180
TJ = 150 °C
Package failure rate
0.0031
7-pin TO220
Environment factor
4.0
Mobile ground environment
Quality factor 10
Commercial level
Learning factor 1
> 2 yrs in production
18.124
MTTF
6.3 yrs

7. Linear Gate/Logic Array (Mil-Hdbk-217F)
Voltage Regulator:
Linear Gate/Logic Array (Mil-Hdbk-217F)
Parameter
Description
Value
Comment
Die complexity failure rate
0.01
11+ transistors
Temperature factor
180
TJ = 150 °C
Package failure rate
3-pin TO220
Environment factor
4.0
Mobile ground environment
Quality factor 10
Commercial level
Learning factor 1
> 2 yrs in production
18.01
MTTF
6.34 yrs

8. FMECA Chart (Microcontroller failure)
No.
mode
Possible Cause
Failure Effects
Detection
Method
Criticality A1
Overcurrent
C1, C4 shorted
Damage micro
Observation
High A2
Micro can’t be
Programmed
C1, C3 or C4 open
Micro not functioning
ICD3 debugger A3
ATD not functioning
R4 shorted
Cannot dodge obstacle A4
PWM not functioning
Oscillator failure
Vehicle not moving A5
UART not functioning
RF module failure
Cannot receive GPS coordinates

9. Microcontroller Schematics

10. FMECA Chart (H-bridge failure)
No.
mode
Possible Cause
Failure Effects
Detection
Method
Criticality B1
H-bridge overheat
Motor overcurrent
Vehicle stops
Observation
Low B2
H-bridge undervoltage
Battery depleted
Vehicle stops halfway
Wheels slowing down
Medium B3
H-bridge
overcurrent
Motor or power supply shorted,
High B4
Motor full-speed backwards
IN1 shorted to GND
Vehicle not moving forward

11. H-bridge schematics

12. FMECA Chart (Regulator failure)
No.
mode
Possible Cause
Failure Effects
Detection
Method
Criticality C1
Regulator overheat
C5 or C6 shorted
Power supply burns out
Observation
High C2
Switch failure
Toggle shorted
Unable to turn off power
LED D1 always on
Low C3
Output voltage noisy
C6 open
Micro not function properly C4
Vout < 3.3 V
Battery depleted
Circuit not functioning properly

13. Power supply schematics

14. Questions?