Spreadsheet: 22495525-8082-44b6-9f0e-4593ab2ab45d
Sheet: Sheet1

Unnamed: 0 | Unnamed: 1 | Unnamed: 2 | Unnamed: 3 | Unnamed: 4 | Unnamed: 5 | Unnamed: 6 | Failure Mode, Effects, and Criticality Analysis (FMECA) of Tracks Sub-System | Unnamed: 8 | Unnamed: 9 | Unnamed: 10 | Unnamed: 11 | Unnamed: 12 | Unnamed: 13 | Unnamed: 14 | Unnamed: 15 | Unnamed: 16 | Unnamed: 17 | Unnamed: 18 | Unnamed: 19 | Unnamed: 20 | Unnamed: 21 | Unnamed: 22 | Unnamed: 23 | Unnamed: 24
 |  |  |  |  |  |  |  |  | FMEA No. |  |  |  |  |  | ME-DR-1
 |  |  | Sub-system: | Tracks |  |  | P = Probability of Occurrence |  | Final Design Deadline: |  |  |  |  |  | 2010-05-03 00:00:00
 |  |  | System: | A.R.T.E.M.I.S. PRIME Lunar Excavator |  |  | S = Severity of Failure Effect |  | Prepared by: |  |  |  |  |  | [NAME]
 |  |  | Design Responsibility: | ME Sub-Team: C. Gries, [NAME], [NAME] |  |  | D = Probability of Detection |  | FMEA Date (Orig.) |  |  |  |  |  | 2010-05-18 00:00:00
 |  |  |  |  |  |  | RPN = Risk Priority Number |  | FMEA Date (Rev.) |  |  |  |  |  | 2010-07-24 00:00:00
Assessment Number |  |  | Component / Subsystem Name | Function | Potential Failure Mode(s) | Potential Effect(s) of Failure | Potential Cause(s) / Mechanisms of Failure | Current Controls (Prevention) | Current Controls (Detection) | Risk Assessment |  |  |  |  | Recommended Action(s) | Responsibility | Action(s) Taken | Revised Risk Assessment
 |  |  |  |  |  |  |  |  |  | P | S | D | RPN | PV |  |  |  | P | S | D | RPN | % RPN Reduction | PV | % PV Reduction
DR - | 1 | a.1 | Control System (Wiring) | Control track motors | Device not actuated | Failure to lift | No power due to faulty electrical connections | Supervision / review by advisor proir to implementation of electrical control system | Device testing | 4 | 7 | 4 | 112 | 16 | Repair Connections | EE sub-team | Connections repaired prior to competition | 2 | 7 | 4 | 56 | 0.5 | 8 | 0.5
DR - | 1 | a.2 | (Wiring) |  |  |  | Failure to execute desired function due to faulty electrical connections |  |  | 5 | 7 | 5 | 175 | 25 | Repair Connections | EE sub-team | Connections repaired prior to competition | 2 | 7 | 5 | 70 | 0.6 | 10 | 0.6
DR - | 1 | a |  |  |  |  |  |  |  | Item RPN & PV |  |  | 287 | 41 |  |  |  | Item RPN & PV |  |  | 126 | 0.5609756097560976 | 18 | 0.5609756097560976
DR - | 1 | b | (Battery) | Control track motors |  |  | No power due to battery charger malfunction |  | Monitor charging battery | 2 | 7 | 5 | 70 | 10 | Rectify charger issue; charge battery | EE sub-team |  | 2 | 7 | 5 | 70 | 0 | 10 | 0
DR - | 1 | c | (Code) |  |  |  | Failure to execute desired function due to incorrect code (progamming issue) | Supervision / review by advisor proir to implementation of electrical control system | Device testing | 5 | 7 | 5 | 175 | 25 | Revise Code | EE sub-team | Code revised prior to competition | 1 | 7 | 5 | 35 | 0.8 | 5 | 0.8
DR - | 1 | d | (Interface) |  |  |  | Mistake by operator at human-machine interface (HMI) | Practice under competition-simulated conditions | Observaton (during device testing / practice) | 6 | 1 | 1 | 6 | 6 | Continued Practice | C. Gries | Gries practiced both at WKU and at [NAME] as able | 2 | 1 | 1 | 2 | 0.6666666666666666 | 2 | 0.6666666666666666
DR - | 1 | e.1 | (Robot-Solutions RS80D Motor Controller) |  | Correct commands not sent to motor | Failure to drive | Motor controller fault | Supervision / care taken during operation | Device testing | 3 | 7 | 1 | 21 | 3 | Replace / repair controller. Determine cause of fault and take action to prevent recurrence | EE sub-team |  | 3 | 7 | 1 | 21 | 0 | 3 | 0
DR - | 1 | e.2 |  |  | Track motors unintentinally set at full speed | Inability to stop tracks | Controller locked in "on" mode due to inactivity of controller code | Emergency stop implemented |  | 8 | 10 | 1 | 80 | 8 | Revise to send "stop" command often enough to keep motor controller active | EE sub-team | Code revised to send "stop" command often enough to keep motor controller active | 2 | 10 | 1 | 20 | 0.75 | 2 | 0.75
DR - | 1 | e |  |  |  |  |  |  |  | Item RPN & PV |  |  | 101 | 11 |  |  |  | Item RPN & PV |  |  | 41 | 0.594059405940594 | 5 | 0.5454545454545454
DR - | 1 | f | (CSD Controller Board) | Command motor controller | Correct commands not sent to motor controller | Failure to lift | Controller board fault | Supervision / care taken during operation | Device testing | 4 | 7 | 1 | 28 | 4 | Replace / repair board. Determine cause of fault and take action to prevent recurrence | EE sub-team | Board replaced prior to competition | 6 | 7 | 1 | 42 | -0.5 | 6 | -0.5
DR - | 1 |  |  |  |  |  |  |  |  | Electrical RPN & PV |  |  | 667 | 97 |  |  |  | Electrical RPN & PV |  |  | 316 | 0.5262368815592204 | 46 | 0.5257731958762887
DR - | 2 | a | Track Motors | Move Tracks | Functional Device Failure | Failure to drive | Overload | Derating of motors | Device Testing | 5 | 8 | 2 | 80 | 10 | Repair motor(s); decrease load; if necessary purchase new motors with increased power capabilities | EE sub-team; ME sub-team |  | 5 | 8 | 2 | 80 | 0 | 10 | 0
DR - | 2 | b |  |  |  |  | Fatigue |  |  | 3 | 8 | 3 | 72 | 9 |  | EE sub-team; ME sub-team |  | 3 | 8 | 3 | 72 | 0 | 9 | 0
DR - | 2 | c |  |  | Motors running at different speeds | Curved path for tracks | Incorrect code for motor speeds |  | Device Testing | 5 | 4 | 1 | 20 | 5 | Modify code | EE sub-team | Conducted limited testing to determine appropriate PWM values (for motor speeds); modified code accordingly | 5 | 4 | 1 | 20 | 0 | 5 | 0
DR - | 2 |  |  |  |  |  |  |  |  | Item RPN & PV |  |  | 172 | 24 |  |  |  | Item RPN & PV |  |  | 172 | 0 | 24 | 0
DR - | 3 |  | Gears | Reduce speed, increase torque | Interference | Damage to gears | Misalignment | Modification to supplied mounting plate | Device testing | 4 | 1 | 9 | 36 | 36 | Additional mounting plate modification | ME sub-team |  | 4 | 1 | 9 | 36 | 0 | 36 | 0
DR - | 4 | a | Support Rods | Support Load | Yielding failure | Warping of overall track structure | Overload | Derating of tracks | Device Testing | 2 | 2 | 1 | 4 | 2 | Replace Components | ME sub-team |  | 2 | 2 | 1 | 4 | 0 | 2 | 0
DR - | 4 | b |  |  | Ultimate failure (bending) | Weakening of overall track structure |  |  |  | 1 | 4 | 1 | 4 | 1 | Replace Components | ME sub-team |  | 1 | 4 | 1 | 4 | 0 | 1 | 0
DR - | 4 |  |  |  |  |  |  |  |  | Item RPN & PV |  |  | 44 | 3 |  |  |  | Item RPN & PV |  |  | 44 | 0 | 3 | 0
DR - | 5 | a | Treads | Move Tracks | Treads separate | Failure to Drive | Loss of tread connection pins |  | Device Testing | 1 | 8 | 1 | 8 | 1 | Replace connection pins | ME sub-team |  | 1 | 8 | 1 | 8 | 0 | 1 | 0
DR - | 5 | b |  |  | Treads jammed |  | Regolith simulant inside tread joints |  |  | 4 | 8 | 3 | 96 | 12 | Clean treads | ME sub-team | Treads cleaned | 2 | 8 | 5 | 80 | 0.1666666666666667 | 10 | 0.1666666666666667
DR - | 5 | c |  |  | Skip teeth on sprockets |  | Regolith simulant inside |  |  | 4 | 8 | 3 | 96 | 12 | Clean treads | ME sub-team | Treads cleaned; treads modified; brushes implemented on inside of tracks | 5 | 8 | 5 | 200 | -1.083333333333333 | 25 | -1.083333333333333
DR - | 5 |  |  |  |  |  |  |  |  | Item RPN & PV |  |  | 200 | 25 |  |  |  | Item RPN & PV |  |  | 288 | -0.44 | 36 | -0.44
DR - | 6 | a | Support Plates | Support Load | Yielding failure | Warping of overall track structure | Overload |  |  | 2 | 3 | 1 | 6 | 2 | Replace Components | ME sub-team |  | 2 | 3 | 1 | 6 | 0 | 2 | 0
DR - | 6 | b |  |  | Ultimate failure (tearing) | Weakening of overall track structure |  |  |  | 1 | 5 | 1 | 5 | 1 | Replace Components | ME sub-team |  | 1 | 5 | 1 | 5 | 0 | 1 | 0
DR - | 6 | c |  |  |  | Loss of track function |  |  |  | 1 | 8 | 1 | 8 | 1 | Replace Components | ME sub-team |  | 1 | 8 | 1 | 8 | 0 | 1 | 0
DR - | 6 | d |  | Connect / support track components | Yielding failure | Warping of overall track structure |  |  |  | 2 | 3 | 1 | 6 | 2 | Replace Components | ME sub-team |  | 2 | 3 | 1 | 6 | 0 | 2 | 0
DR - | 6 | e |  |  | Ultimate failure (tearing) | Loss of track function |  |  |  | 1 | 8 | 1 | 8 | 1 | Replace Components | ME sub-team |  | 1 | 8 | 1 | 8 | 0 | 1 | 0
DR - | 6 |  |  |  |  |  |  |  |  | Item RPN & PV |  |  | 33 | 7 |  |  |  | Item RPN & PV |  |  | 33 | 0 | 7 | 0
DR - | 7 | a | Supports | Provide rigid connection between right and left tracks | Yielding failure | Tracks out of square; device does not drive straight | Bending stress due to turning | Safety factors  > 1.5 for supports | Device Testing | 3 | 5 | 2 | 30 | 6 | Replace Components | ME sub-team |  | 3 | 5 | 2 | 30 | 0 | 6 | 0
DR - | 7 | b |  |  | Ultimate failure (bending) | Reduced control of track locomotion |  |  |  | 2 | 6 | 1 | 12 | 2 | Replace Components | ME sub-team |  | 2 | 6 | 1 | 12 | 0 | 2 | 0
DR - | 7 | c |  |  |  | Loss of track locomotion |  |  |  | 2 | 8 | 1 | 16 | 2 | Replace Components | ME sub-team |  | 2 | 8 | 1 | 16 | 0 | 2 | 0
DR - | 7 |  |  |  |  |  |  |  |  | Item RPN & PV |  |  | 58 | 10 |  |  |  | Item RPN & PV |  |  | 58 | 0 | 10 | 0
DR - | 8 | a | Scoop | Move obstacles | Operator error | Damage to underside of device | Camera malfunction | Practice under competition-simulated conditions |  | 5 | 4 | 5 | 100 | 25 | Replace / repair camera(s) and/or damaged components; more practice | ME sub-team |  | 5 | 4 | 5 | 100 | 0 | 25 | 0
DR - | 8 | b |  |  |  |  | Insufficient practice |  |  | 7 | 4 | 5 | 140 | 35 | Replace / repair damaged components | ME sub-team |  | 7 | 4 | 5 | 140 | 0 | 35 | 0
DR - | 8 | c |  |  |  | Device immobilization | Camera malfunction | Practice under competition-simulated conditions |  | 5 | 7 | 1 | 35 | 5 | Replace / repair camera(s); more practice; perform maneuvers to mobilize device | ME sub-team |  | 5 | 4 | 1 | 20 | 0.4285714285714285 | 5 | 0
DR - | 8 | d |  |  |  |  | Insufficient practice |  |  | 7 | 7 | 1 | 49 | 7 | Perform maneuvers to mobilize device | ME sub-team |  | 7 | 4 | 1 | 28 | 0.4285714285714285 | 7 | 0
DR - | 8 | e |  |  | Functional subsystem failure | Damage to subsystem | Insufficient scoop component strength |  |  | 7 | 6 | 1 | 42 | 7 | Repair / replace subsystem components | ME sub-team |  | 7 | 6 | 1 | 42 | 0 | 7 | 0
DR - | 8 | f |  |  | Functional subsystem failure | Device immobilization | Insufficient motor (linear actuator) strength |  |  | 3 | 7 | 1 | 21 | 3 | Perform maneuvers to mobilize device | ME sub-team |  | 3 | 4 | 1 | 12 | 0.4285714285714285 | 3 | 0
DR - | 8 |  |  |  |  |  |  |  |  | Item RPN & PV |  |  | 387 | 82 |  |  |  | Item RPN & PV |  |  | 342 | 0.1162790697674419 | 82 | 0
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.2246938708779193 |  | 0.2040254188858664