Eye In The SkyTCSP #8Safety and Reliability Analysis

-Team 3 Joe Katz

Upsham Dawra Samit Sura Ashwin Shankar

Project Overview

o Portable low-cost aerial drone that can be used for reconnaissance

o Relay real-time video and data, like location, heading, battery life

o Take high-resolution pictures of the ground in flight

o Store photos and some flight data in non-volatile memory, á la “blackbox” system.

o Control drone manually via a control unit

Block Diagram

Functional Blocks

Three main functional blocks: Power: LTC1174 (3.3V switching regulator)

and application circuit, FSAL200 (analog multiplexer), DS2438 (battery monitor) and application circuit, opto-isolator

Microcontroller: AT32UC3C0256 Sensors/Peripherals: XBee, MPU-6050 (IMU),

BMP085 (altimeter), HMC6352 (compass), SD card

Schematic: Power

Schematic: Microcontroller

Schematic: Sensors & Peripherals

Reliability Calculations: Part choices

LTC1174: relatively high power and complex compared to other components on our board, high criticality failures associated with failure of this device

AT32UC3C0256: high complexity, relatively high criticality failures

FSAL200: low complexity but high criticality failures

Reliability Calculation: LTC1174 Switch-mode power supply

Model: λP = (C1 πT + C2 πE)πQπL

λP = Total failure rate: 1.86x10-7 per hour

Reliability Calculation: AT32UC3C0256

Microcontroller

Model: λP = λBDπMFGπTπCD + λBPπEπQπPT + λEOS

λP = Total failure rate: 4.619x10-7 per hour

Reliability Calculation: FSAL200 Multiplexer

Model: λP = 20λBπTπQπE

λP = Total failure rate: 6x10-6 per hour

FMECA: PowerFailure No. Failure Mode Possible Causes Failure Effects Method of Detection Criticality

P-1 LTC1174Output = 0V

External short, decoupling capacitor short

Plane stops flying Observation High

P-2 LTC1174Output > 3.3V

Failure of U1 or sensors Control of plane transfers to COTS controller

Observation (controls through computer stop working)

Medium

P-3 LTC1174Output out of tolerance

Failure of L2, clamping diode, or decoupling capacitors

Possible loss of control of plane

Observation High

P-4 Opto-isolator output 0V Burnout, excess current draw from video system (short)

Loss of video streaming Software check low

P-5 FSAL200No Output

Passed too much current, transistor aging

Loss of control of plane Observation High

P-6 FSAL200Stuck at microcontroller output

GPIO failure, internal buffer failure, transistor aging

Dormant control failure Pre-flight test Low

P-7 FSAL200Stuck at COTS controller output

GPIO failure, internal buffer failure, transistor aging

Loss of control through micro

Observation Low

P-8 DS2438Incorrect data

SPI failure Invalid battery data Observation (plane may be unable to climb when it apparently has enough power)

Medium

FMECA: MicrocontrollerFailure No. Failure Mode Possible Causes Failure Effects Method of Detection Criticality

M-1 PWM failure Software error, mechanical vibration/shock, power out of tolerance, transistor aging

Plane stops flying Observation High

M-2 UART failure Software error, mechanical vibration/shock, power out of tolerance, transistor aging

Transfer of control to COTS controller, possibly only loss of GPS data

Observation (controls through computer stop working)

Medium

M-3 SPI failure Software error, mechanical vibration/shock, power out of tolerance, transistor aging

Loss of data storing capability, loss of compass data

Observation Low

M-4 I2C failure Software error, mechanical vibration/shock, power out of tolerance, transistor aging

Loss of motion sensing ability

Software check Low

M-5 GPIO failure Software error, mechanical vibration/shock, power out of tolerance, transistor aging

Loss of control of plane Observation High

FMECA: SensorsFailure No. Failure Mode Possible Causes Failure Effects Method of Detection Criticality

S-1 XBeeLoss of communication

UART failure Transfer of control to COTS controller

Observation Medium

S-2 MPU-6050IMU incorrect data

I2C failure Loss of motion data Software check Low

S-3 SD card not storing data SPI failure Loss of “Black Box” Observation after flight, possible software check

Low

S-4 Altimeter incorrect data SPI failure Loss of altitude sensing capability

Software check Low

S-5 Compass incorrect data I2C failure Loss of heading Software check Low

S-6 GPS incorrect data UART failure Loss of location data Software check Low

Summary

Relatively low reliability Even if this product were brought to

market, production volumes and amount of use would be very low

Intended for use in relatively remote areas

Software will be able to monitor for some low-criticality failures

Feedback

Questions?