RP1: P08205 & P08208
Meeting Purpose
This is the first review of the RP1 Senior Design projects P08205: Wireless PWM Motor Control Focus Group and P08208: Mechanical Design Focus Group, which will collaborate in development of a set of wireless controlled motor modules to transport a 1kg payload. The intent is the introduction of project preparation, planning, and subsystem concepts which have been evaluated via the Pugh method.
Guests have been invited to reflect on the progress of the project, to steer towards better solutions.
Materials Reviewed
CDR_Pre-read.doc (Rev. 02)
Attendees:
Professor Slack (EE / EE Advisor)
Emilien Barrault (ME / French Collaboration Lead)
Ryan Hellems (ME / P08002 member)
Jessica Stalker (ME / P08002 member)
Jeffery Ozbourne (ME / P08002 member)
Recorded by (names and roles of person recording meeting notes):
Art Ponikiewski / Matt Benedict / Phil Edwards / Reid Williamson (Team members)
Meeting Date:
01.18.08
2:00PM – 4:00PM
Mobil Conference Room
Previous Open Action Items Reviewed
N/A – First Review
Discussion (describe any relevant discussions not captured in actions / issues / decisions tables):
- “What do You want to get out of this review?” (E.H.)
- Long-term Outlook - Packaging Science Collaboration
- Can they provide rudimentary recommendations?
- Could table top drop test requirement spin off to be a packaging science project?
- Scope of Performance (E.H.)
- Reliability / “It works”
- Rudimentary Controls from base
- Rudimentary Health Statements from MM
- Advanced Health Commands from MM
- Report Health wirelessly to user (not expected)
- Functionality of Wireless
- Commands & Data
- 802.11 has a lot of software overhead
- Zigby is not trivial
- Adaptability to increased signal traffic
- Wireless RS-232
- Individually addressable?
- Easier to develop
- Distribution Requirements (range)
- Function of visual operating range
- Integrate subsystems (E.H.)
- (Open Source or Open Architecture) ≠ COTS
- Processor Type Screening Stage Matrix
- Microcontroller Only lacked a specified board design
- What if the control commands are not from a human?
- Expandable to autonomous control…?
- Be sensitive to wheel slip
- Joystick = higher resolution while keyboard = lower resolution
Action Items
Item # / Description / Responsible / Due Date / Close Date / Comments
A001 / Edit grammar of “Wireless PWM Communications” to read “PWM controlled motors to be controlled by wireless communication”
(Slack) / Wendy / 01.24.08 / Updated to Rev 3
A002 / Req’t: Edit “remote controlled” to read “Wireless control” / Reid / 01.22.08 / QFD updated
A003 / Contact Packaging Science Students
-Simple suggestions
-Continued project potential / Reid / 01.24.08 / 4 students contacted
A004 / Req’t: Backward compatible with prior generation command sets
[I015] / Phil / 01.28.08 / QFD updated so Backwards compatibility is a requirement
A005 / EM: Edit to be “Cost of Product per Project Team” / Reid / 01.22.08 / QFD updated
A006 / EM: Clarify target spec to be “HxWxD” / Reid / 01.22.08 / QFD updated
A007 / EM: Evaluate target of < 100 unique components
- Count/Estimate # of unique components on RP10
- “high”
A008 / Review P07201’s concerns about bevel gears
[I007] / Andrew
Matt / 01.25.08
A009 / Review P07201’s “future work” / ALL / 01.25.08
A010 / Review RP10 Customer Req’ts / Reid / 01.28.08
A011 / Needs: Estimate operational range of wireless communication / Brendan / 01.28.08 / QFD updated
A012 / EM: Correct to read “Weight of platform and platform components” / Reid / 01.22.08 / QFD updated
A013 / EM: Evaluate accuracy target, 2 in/12in
(E.H)
[I016] / Andrew
Matt
A014 / If there is drift in the linear drive, and some slop, Quantify overall accuracy of system [%]
(E.H.) / End of MSD II
A015 / EM: Correct to be “time to attach each MM” / Reid / 01.22.08 / QFD updated
A016 / Req’t: Make safety a yes/no user requirement / Reid / 01.22.08 / QFD updated
A017 / Develop functional diagram for user inputs
(Slack) / Phil / 01.30.08
A018 / Fix MS Project Schedule Errors
- Add Wk 10 – Proj Presentations
- Correct items lacking date
A019 / Evaluate use of C-channels in Yoke Design
(WWW) / Eric / 01.25.08 / Costly material & more complex
A020 / Evaluate “Everything on MM” Option
- Project cost
- Project weight
- Evaluate on cost, weight, and user value, and complexity
Brendan / 01.25.08 / Increase cost, difficulty to assemble, complexity of wireless, and identification.
A021 / Determine I/O location limits of microcontroller
(E.H.) / Brendan / 01.29.08 / 8 PWM channels
40 I/O pins
A022 / Feasibility study of regenerative braking
(E.H)
[I003] / Bryan
Jon / 01.29.08 / Micro Controller would have to be changed. Costly
A023 / Determine wireless functionality requirements
- Data rate
- # of nodes
- Range
Phil / 01.28.08 / Reference QFD.xls
A024 / Evaluate method of achieving “Health” feedback
(E.H.)
[I006] / Brendan
Phil
Jon / 01.28.08 / Wireless. Microprocessor does not have enough memory
A025 / Needs: Estimate battery life / Jon / 01.25.08
A026 / Evaluate RS-232 / Brendan
Phil / 01.25.08 / Now preferred over Crossbow
Issues
Item # / Description / Responsible / Open Date / Close Date / Comments
I001 / Customer Requirements:
Is remote control = wireless?
(Slack) / Reid / 01.25.08
I002 / H-bridge =?= Motor controller
(see functional diagram) / Controls / 01.25.08
I003 / Is regenerative braking achievable? Desirable for future teams
(E.H.)
[A022] / Bryan
Jon / 01.25.08 / Micro Controller would have to be changed. Costly
I004 / “Are Pugh Matrix rankings on engineer’s opinion or quantifiable facts”
(Drive)
(E.H.) / Andrew / 01.25.08
I005 / Does MM need to be individually addressable?
-Addressable with own receiver?
-Controllable via single mote? / Electronics / 01.25.08 / Yes, ID needs to be required.
Yes, controllable by single mote.
I006 / How to communicate Motor Module “Health?”
-Store for post-run
-Transmit wirelessly
- Data transfer limitations of wireless network
[A024] / Brendan
Phil / 01.25.08 / Microprocessor does not have necessary memory for data logging; therefore wireless transfer of data is preferred.
I007 / Susceptible design of bevel gears
(E.H.)
[A008] / Mechanical Design
Andrew
Matt / 01.30.08 / Implement bracket to ensure good mesh
I008 / Drive System:
-Time to replace belt?
-Time to replace bevel gear?
-Time to replace wheel?
-Gear ratio?
(E.H.) / Andrew / To be evaluated
I009 / Critical Design Point:
-Teeth mating
-Miter gear misalignment
-“Cantilevered shaft off of bearing is not a robust design”
-Axels
(E.H.) / Mechanical Design
Andrew
Matt / 01.30.08 / Implement bracket to ensure good mesh
I010 / “How do you even know that your drive system will work?”
-motor curve
-electrical constraints on motor
- PWM signal
- Excess heat
Jon
Bryan / 01.30.08 / Motor curves have been analyzed to find RPM with max efficiency. MC uses a fuse.
Steering motor is most concerning.
I011 / Is duty cycle proportional to linear speed?
(Slack) / Controls / 01.30.08 / Close to proportional.
I012 / In-rush current @ high duty cycles
(Slack) / Jon / 01.30.08 / MC uses a fuse.
Steering motor is most concerning.
I013 / Correct speed requirement
- Is 10 in/s too much? / Andrew / 01.25.08 / “Sweet Spot” Speed ~ 29 in/s at 4:1 gear ratio
I014 / Architecture of application level
(Slack) / Phil / 01.30.08 / See Sys DR material
I015 / Backwards compatible software command sets
- Software used?
- Functionality?
- Weaknesses
- Improvements
- P08201 approach
I016 / EM: Accuracy of Movement EM
- “linear variation over transverse movement”
- “tighten up target specs”
[A013] / Andrew
Matt / 01.30.08 / One spec to ensure both functions and their impact on the system. Linear variation will be evaluated at 0, 15, 30, and 45 degrees from path of forward motion
I017 / Wireless Pugh: Products cannot be compared to platforms which are not hardware. / Brendan / 01.25.08 / QFD updated
I018 / What are the wireless functionality specs?
- Commands & Data
- Software overhead
- Capacity with multiple products operating at once
- Distribution (range)
Phil / 01.25.08 / 200 B/s < Data rate <2000 B/s
~ 128 Nodes
Wireless protocol required to manage network
Networking is easier with Crossbow
I019 / Is a current limiting device needed prior to the MC? / Jon / 01.25.08 / MC has fused sensor and additional senor not likely
I020 / What pre-fab circuit?
- If Freescale chip, support choice (yes, a faculty supported chip is a smart choice)
- Disadvantages to Freescale?
Jon / 01.25.08 / Freescale board chosen.
Circuit required if Zigby
I021 / What export controls might limit the shipping of a RP1 MM to INSA, in France?
- ex. encryption software
I022 / Robotics Club inability to maintain members / N/A / Collaboration has been pursued. Out of the scope of the project.
I023
I024
I025
I026
I027
I028
I029
I030
I031
I032
Decisions
Item # / Description / Responsible / Decision Date / Comments
D001 / On-board battery re-store not required / Dr. Hensel / 01.18.08
D002 / Design for integration of P08201 MC / Dr. Hensel / 01.18.08 / Should be swappable
D003 / Prototype by the end of SDI – Customer wants a good end product, not necessarily a prototype. A prototype would be hands on time. / Dr. Hensel / 01.18.08 / Hands-on-time will be pursued with baseline kit, ordering electronic components to prove feasibility, and prototyping of yoke for rigorous drop testing
D004 / End goal of RP family is idiot proof “plug-and-play” / Dr. Hensel / 01.18.08
D005 / Design Review Format should be changed to allow more break-out time and less listening / Dr. Hensel / 01.18.08
D006
D007
D008
D009
D010
D011
D012
D013
D014
D015
KGCOE MSDPage 1 of 9Concept Design Review