2018:Robot Design Details

Overall design decisions, notes, specifications, and integration items here! Integration Task List (needs link)

Overall Robot Dimensional Restraints

Last updated 1/11/2018

After a coordination session with mechanical subteams we reached the following dimensional guidelines for all subteams to keep in mind.  Sketches (hopefully) to be added Thursday:

• Drive Base: 
  • We will be a narrow bot with our CUBE intake side(s) being 27.75" and our ramp deploy side(s) being 32.75".
  • We may be a "U" or "H" or solid rectangular drive base frame.  We will have a decision on this by Saturday night.  In the meantime, drive base is focusing on the side rail design.
  • The battery will be located in the back of the drive base. 
  • Bottom Clearance is 1.25 inches, 
  • Top of Drive Base is at 4.25 inches with total gear clearance at 4.83 inches.
• CUBE Mechanism:  Please note, this section breaks the CUBE mechanism into FOUR parts: Intake ("touch it own it"), Stabilizer (holds the CUBE firmly in an orthogonal orientation), and Arm (moves the CUBE), and Outtake (CUBE exits the mechanism). 
  • Following bumper rules, we have 15.75" of width for all parts of the CUBE mechanism that rests against the drive base frame.  All other parts must deploy over the bumpers.
  • CUBE mechanism must comply with 16" extension rule (be careful with pivots!).
  • "Going Thru the Robot" with the CUBE creates three possible pinch points:
    • A CUBE mechanism with a fixed Arm (that has the Intake/Outake/Stabilizer attached) rotating 180 degrees from robot front to robot back creates an arched ceiling underneath it that the ramp storage must fit under for the width of the Arm/Intake/Outake/Stabilizer.
    • A CUBE mechanism with any Arm design rotating 180 degrees from robot front to robot back creates a path through the center that nothing else can occupy.
    • A CUBE mechanism with any parts that extend outside the drive base require space to store those parts in the Start Configuration that could impact ramp storage.
  • If the CUBE Arm has 1 pivot point (at the base), in order to rotate 180 degrees with Intake and Outtake of the CUBE at the floor (13" CUBE orientation is min on the floor front and back, 11" CUBE orientation is min on the floor front and min. 1" off the floor back) then the centerline of the Arm is approximately 6.5" off the ground.
    • If the Arm has 2 pivot points (at the base and one creating two segments) this constraint may not apply.
    • If the Arm has 2 pivot points and the Intake/Outtake/stabilizer articulates at the end of the Arm, this constraint may not apply.
    • If the Arm has 1 pivot point and the Intake/Outtake/Stabilizer articulates at the end of the Arm, this constraint may not apply.
    • If the Intake/Outtake is attached only to the drive base and the Stabilizer is on the Arm, this constraint does apply. Please note in this instance the ability to Outtake into the SWITCH may be compromised.  It also implys that we are duplicating the Outtake or designing a second Outtake to deploy the CUBE at the front and back of the robot.

Actuators

This is preliminary and subject to change!

Motors

Mechanism	Action	Minimum Breaker Size	Motor Model #	Quantity	Notes
Intake	Grabs the cube and puts it in the hand	?? 30A ??	775 Pro	2 - one left, one right
Arm	Pivots arm to robot/front back	?? 30A ??	775 pro	1
Hand	holds the cube as it moves around the robot and deploys the cube	?? 30A ??	775 pro	1
Ramp	Lifts the ramps with robots on top	?? 30A ??	775 pro	4, 2 per ramp	2 Lift systems (jacks) per ramp, 1 motor on each
Drive Base	Moves the robot	?? 40A ??	CIM	6

Pneumatics

Mechanism	Action - Say what extend and retract do!	Cylinder	Extend Powered?	Extend Exhaust to Atmosphere?	Retract Powered?	Retract Exhaust to Atmosphere?	Working Pressure	Estimated Firings per Match (Sum of all powered directions!)	Notes
Intake	Extend = raise intake into robot Retract = lower intake to retrieve cubes	Bimba M-044-DP. Magnetic 3/4" bore 4" stroke, pivot mount	Yes	Yes	Yes	Yes	60 PSI	?
Arm Brake	Extend (spring loaded extension) = disengage brake Retract = Engage brake	Bimba 041-D. 3/4" bore 1" stroke	No	Yes	Yes	Yes	60 PSI	?
Hand on Arm	Retract = "close" hand, tighten on cube Extend = "open" hand, loosen grip on cube	Bimba 042-D. 3/4" bore 2" stroke	No	Yes	Yes	Yes	?? PSI - 60 may be too high	?
Ramp	Hold/Release ramp system. Extend = ? Retract = ?	?	?	?	?	?	?	?	?

 

 

Sensor Chart

Mechanism	Sensor Type	Function	Attachment Point	Notes
Intake	Magnetic reed switches (2) on pivot cylinder	Senses when cylinder has completed up and down motion	On cylinder
Arm	Potentiometer	Absolute rotation position of arm.	On actual pivot/shaft.
Arm	???	Tripped at end of travel/at hard stop on front of robot	???
Arm	???	Tripped at end of travel/at hard stop on back of robot	???
Hand on Arm	Retro-reflective beam sensor	Sense cube all the way into hand	Mounting is important! Must look "sideways" at the cube where it hits the backstop.
Ramp	Integrated Versa Planetary Encoder	Sense travel and speed of lead screw on lift jacks One phase	4 total, 1 on each jack - Sensor should be at output stage of each gearbox
Ramp	????	Sense when ramp jacks are fully reset (not used during match)	4 total, 1 on each jack - ADD MOUNTING DETAILS ONCE SENSOR IS KNOWN
Drive	Shaft encoders	Travel of robot drive base. One phase	On center (traction) wheel shaft.
Whole robot	Gyro	Sense rotation	Must be center of rotation of robot away from excessive vibration sources
Whole robot	Camera	??Visual feedback for lining up with exchange??	???

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