Technical Communication Skills

Practicum (TCSP)

Presented by Nuhairi & Azad

Team 10: “Hazard Rover”

2/21/2007

HAZARD ROVERHAZARD ROVER

At-A-Glance:At-A-Glance:– Web-based Wi-Fi control interfaceWeb-based Wi-Fi control interface– Wireless webcam streams video to Wireless webcam streams video to

websitewebsite– Capabilities:Capabilities:

MovementMovement Light sensor/LEDLight sensor/LED Robotic ArmRobotic Arm

– Model, designed for use in hazardous Model, designed for use in hazardous areasareas

HAZARD ROVERHAZARD ROVER

SCHEMATICSCHEMATIC

six different subsystems: Power Supply (P), Sensors (S), Motor Control (D), Microcontroller (M), Wi-Fi Interface (F), and Webcam (W)

OVERALL SCHMEMATICOVERALL SCHMEMATIC

ARM MOTORARM MOTOR

POWERPOWER

CAMERA SERVOCAMERA SERVO

STEERING MOTORSTEERING MOTOR

STEERING SENSORSTEERING SENSOR

LEVELS OF CRITICALITYLEVELS OF CRITICALITY

– NegligibleNegligible Rover can continue to function close to Rover can continue to function close to

normallynormally

– Potentially HazardousPotentially Hazardous Rover may be able to function partially Rover may be able to function partially

depending on severity of failuredepending on severity of failure

– HazardousHazardous Failure will result in the rover’s inability to Failure will result in the rover’s inability to

complete its taskcomplete its task

– DangerousDangerous Failure could possibly cause the rover to Failure could possibly cause the rover to

become a destructive force.become a destructive force.

FMECA Analysis: Power FMECA Analysis: Power SupplySupply

Failure No.

Failure Mode Possible Causes Failure Effects Method of Detection Criticality

P1 Battery Voltage too low

Chemical defect in battery, overuse, needs

recharging

Possible inoperation of other components

Dim LED, voltmeter, lack of functionality of some components, battery life

readings on microcontroller incorrect

Potentially Hazardous

P2 Voltage Regulator output

too high

Input too high, short within regulator

Damage to any components supplied by

regulator, overheating

Regulator or other components heating up, not functioning properly

Hazardous

P3 Voltage Regulator output

too low

Faulty/shorted bypass capacitor (C8), Input too low, short within

regulator

Possible inoperation of components supplied by

regulator

Dim LED, voltmeter, lack of functionality of some

components

Potentially Hazardous

FMECA Analysis: SensorsFMECA Analysis: SensorsFailure

No.Failure Mode Possible Causes Failure Effects Method of Detection Criticality

S1 Light sensor readings inaccurate

Obstruction of sensor, parts of sensor faulty

Inaccurate readings, improper LED function

LED does not light up in the dark, or lights up

in the light

Negligible

S2 LED always on Improper readings, short in connections

More power consumption, possible

damage to microcontroller

LED is always on Negligible

S3 LED always off LED burned out, short in connections

Possible lack of night vision, possible damage

to microcontroller

LED is always off Negligible

FMECA Analysis: Motor FMECA Analysis: Motor ControlControl

Failure No.

Failure Mode Possible Causes Failure Effects Method of Detection Criticality

D1 Pan/Tilt servos not moving

properly

Damage to motor, input signal is too fast for AND gate tolerance (U17A,B)

Inablility to move camera, possible

damage to AND gates

Camera movement not operational, motors

heating up

Hazardous

D2 Pan/Tilt servos not

moving/stuck

Faulty AND gate, short in motor

Inability to move camera, possible

damage to AND gates

Camera movement not operational, motors

heating up

Hazardous

D3 Arm/steering motors always

off

Faulty bypass capacitor, faulty DC Motor Driver,

short in motor

Damage to driver chip, motors, or

microcontroller

Inability to move robotic arm or steer, motors getting hot

Hazardous

D4 Arm/steering motors always

on

Short in Driver chip, connections from microcontroller

Damage to driver chip, motors, or

microcontroller

Steering always in the same direction, robotic

arm stuck in one position

Hazardous

D5 Drive motor always off

Short in H-Bridge chip, connections to microcontroller

Damage to driver chip, motor, or

microcontroller

Inability to move Hazardous

D6 Drive motor always on

Short in H-Bridge chip, connections to microcontroller

Damage to driver chip, motor, or

microcontroller

Inability to stop or control rover

Dangerous

FMECA Analysis: FMECA Analysis: MicrocontrollerMicrocontroller

Failure No.

Failure Mode Possible Causes Failure Effects Method of Detection Criticality

M1 Output not correct

Possible corruption of assembly code in memory, shorts within or near ports

Incorrect operation of components connected

to microcontroller

Incorrect operation of various components

Potentially Hazardous

M2 Output not present

Microcontroller not receiving power, damaged

microcontroller

Inoperation of all components

Inoperation of all components

Hazardous

FMECA Analysis: Wi-Fi FMECA Analysis: Wi-Fi InterfaceInterface

Failure No.

Failure Mode Possible Causes Failure Effects Method of Detection Criticality

F1 Data received from Wi-Fi link

incorrect

Possible short in connection, signal interference, faulty

wireless bridge

Damage to microcontroller, wireless bridge

Operation of components not to user’s specification

Potentially Hazardous

F2 No data received from Wi-Fi link

Broken connection, damage to wireless bridge

Microcontroller software detection

should stop all rover movement

All movement on rover stops

Hazardous

FMECA Analysis: WebcamFMECA Analysis: Webcam

Failure No.

Failure Mode

Possible Causes Failure Effects Method of Detection Criticality Remarks

W1 Webcam video data corrupted

Possible short in connection, signal interference, faulty wireless webcam link, weak signal

Possible damage to webcam/receiver

Video data not present or

distorted/corrupted

Potentially Hazardous

W2 Webcam video data not present

Broken connection, damage to

webcam/receiver

No video feed to user, possible

damage to webcam/receiver

No video feed to user Hazardous In this case, the user should stop moving all motors to prevent any

further dangerous situations