Technical Communication Skills Practicum (TCSP) Presented by Nuhairi & Azad Team 10: “Hazard Rover” 2/21/2007

HAZARD ROVER At-A-Glance: At-A-Glance: –Web-based Wi-Fi control interface –Wireless webcam streams video to website –Capabilities:  Movement  Light sensor/LED  Robotic Arm –Model, designed for use in hazardous areas

HAZARD ROVER

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

OVERALL SCHMEMATIC

ARM MOTOR

POWER

CAMERA SERVO

STEERING MOTOR

STEERING SENSOR

LEVELS OF CRITICALITY –Negligible  Rover can continue to function close to normally –Potentially Hazardous  Rover may be able to function partially depending on severity of failure –Hazardous  Failure will result in the rover’s inability to complete its task –Dangerous  Failure could possibly cause the rover to become a destructive force.

FMECA Analysis: Power Supply Failure No. Failure ModePossible CausesFailure EffectsMethod of DetectionCriticality P1Battery 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 P2Voltage 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 P3Voltage 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: Sensors Failure No. Failure ModePossible CausesFailure EffectsMethod of DetectionCriticality S1Light 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 S2LED always onImproper readings, short in connections More power consumption, possible damage to microcontroller LED is always onNegligible S3LED always offLED burned out, short in connections Possible lack of night vision, possible damage to microcontroller LED is always offNegligible

FMECA Analysis: Motor Control Failure No. Failure ModePossible CausesFailure EffectsMethod of DetectionCriticality D1Pan/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 D2Pan/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 D3Arm/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 D4Arm/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 D5Drive motor always off Short in H-Bridge chip, connections to microcontroller Damage to driver chip, motor, or microcontroller Inability to moveHazardous D6Drive 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: Microcontroller Failure No. Failure ModePossible CausesFailure EffectsMethod of DetectionCriticality M1Output 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 M2Output not present Microcontroller not receiving power, damaged microcontroller Inoperation of all components Hazardous

FMECA Analysis: Wi-Fi Interface Failure No. Failure ModePossible CausesFailure EffectsMethod of DetectionCriticality F1Data 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 F2No 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: Webcam Failure No. Failure Mode Possible CausesFailure EffectsMethod of DetectionCriticalityRemarks W1Webcam 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 W2Webcam video data not present Broken connection, damage to webcam/receiver No video feed to user, possible damage to webcam/receiver No video feed to userHazardousIn this case, the user should stop moving all motors to prevent any further dangerous situations