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[DPRG] Big Robot Project

Subject: [DPRG] Big Robot Project
From: paradug paradug at gmail.com
Date: Wed Jan 15 16:54:56 CST 2014

Correction: Pipe OD is 4.2” not 4.1”.

From: Doug Paradis 
Sent: Wednesday, January 15, 2014 4:09 PM
To: dprg.org 
Subject: Re: [DPRG] Big Robot Project

Here is a picture of Ron Grant's model of the Big Robot Project. 


Doug P.

On Wed, Jan 15, 2014 at 3:52 PM, Doug Paradis <paradug at gmail.com> wrote:

  At this week’s RBNO,  the Big Robot Project was a subject of a long discussion/brain storming session. RBNO was well attended and a lot of design points were settled. Also, a few to-dos were generated. Thanks to notes from Steve Edwards, I will summarize where the project is going. 

       Build a 6 foot tall pose-able robot that would be used for DPRG booth demonstrations.  
       The robot would:
              1.  Follow closely the model proposed by Ron Grant at the January monthly DPRG meeting.
                       This model includes:
                             1.  One DOF joints at shoulder and leg/waist - sleeve over shaft type.
                             2.  One DOF joints at both knees and elbows – hinge type.
                             3.  Neck joint would have pan and tilt capabilities.
                             4  Leg and Arm sections are made of 4” PVC thin-wall pipe with ID = 4.0” and OD = 4.1”.
                             5.  Head and torso sections have a generally rectangular shape. Constructed of flat panels set into frames.
              2.  Robot functions in order of priority are:
                      1.  Head able to track a human face.
                      2.  Right wrist capable of rotation at least 180 degrees – wave.
                      3.  Left arm capable of at least 90 degree rotation at elbow  -- raise forearm.

      [  ]  Make model files available to group.(ASAP)  - Ron G.
      [  ]  Explore use of worm gear vs. counter-weight based method for elbow joint (next RBNO) – John K. and David K.
      [  ]  Torso frame rough design (next RBNO) – David K.
      [  ]   Print example hinge type joint (on availability of model files) (next RBNO) – Jason H.
      [  ]  Summarize meeting results (ASAP) – Doug P. 

      1.  Motors will be bipolar stepper motors.
      2.  Motor Controllers will be Pololu stepper motor controller type (real or clone) or L298N eBay type .
      3.  Robot will use laptop for primary computation and vision system. 
      4.  Primary embedded controller will be Arudino Mega R3. 
      5.  Pre-posed arms considered as alternative for several joints (depends on outcome of demo joint).
      6.  Panel material 1/8 inch Plexiglas.
      7.  Frame material light slotted angle iron (steel or Al).
      8.  Wrist end effectors – non-functional 3-D printed stylized grippers. 
      9.  Use shear pins when possible to prevent damage.
    10.  Neck joint design proposal:  
    11. Use 4.1” circular sleeve as least 4” long as standard interface between modules to allow replacement or upgrade of joints or end effectors.

  AVAILABLE RESOURCES (Donations if needed):
      1.  Laptop  -- Jason H.
      2.  Webcam  -- Richard N.
      3.  Stepper Motors (various sizes) –  Jason H., Doug P.
      4.  Up to 10 feet of 4” thin wall PVC pipe – Ron G.
      5.  DDT500 pan and tilt adapter – Ron G.
      6.  L298N type stepper motor controllers (up to 4) – Doug P.
      7.  Batteries up to 2 (laptop / LiPo) – Jason H.
      8.  Arudino Mega controller board – ?  (If anyone has an extra, please....) 

  Finally, welcome to new DPRG member, David Kessinger. David’s area of expertise is on the mechanical side.

  Doug P.

  On Mon, Jan 13, 2014 at 11:21 AM, Ron Grant <deltagraph at aol.com> wrote:


    The pipe that would make arm / leg segments for 6' robot is 4" PVC Thin-Wall Pipe (Sewer / Drain Pipe). I have at least one spare 10 foot long piece.

    ID = 4.0"
    OD= 4.2"  (0.100" wall)

    The commonly available schedule-40 pipe is too thick and heavy.  (closer to 0.25" wall thickness)

    If the existing model was scaled you would only need 5 feet of pipe.

    (6) Upper / Lower Leg segments, upper arm at 8" long each
    (2) Lower-Arm at 6" long each

    I will get together some drawings of the model I built.


    > What size pipe did you bring to the meeting on Saturday? I remember 2 sizes but thought that a specific >size would scale properly to a 6 foot robot. Regards, Doug P. 

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