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.
This is preliminary and subject to change!
|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||15"1 gear ratio - 5:1 and 3:1 in versa planetary gearbox|
|Arm||Pivots arm to robot/front back||30A||775 pro||1||50:1 gear ratio: 5:1, 5:1 in versa planetary, 18T timing pulley on motor, 36T timing pulley on axle. If belt fails, wil chane to 15T sprocket on motor, 32T sprocket on axle.|
|Hand||holds the cube as it moves around the robot and deploys the cube||30A||775 pro||1||Starting ration will be16:1 - (2) 4:1 in the versa panetary gearbox.|
Lifts the ramp/platform with another team's robots on top
|30A||775 pro||4, 2 per lift||2 Lift systems (jacks) per ramp, 1 motor on each|
|Drive Base||Moves the robot||40A||CIM||6 (dropped to 4)||Gear ratio 14:64|
|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!)
|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||40||
Assumes a defensive game (retract to prevent damage)
RB1 on order
RB2 on shelf
Extend (spring loaded extension) = disengage brake
Retract = Engage brake
|Bimba 041-D. 3/4" bore 1" stroke||No||Yes||Yes||Yes||60 PSI||
(Review comment: Would expect this to be greater than # of intake firings even under severe defense due to uncertainty of how to use cube and putting in "up" position for any substantial movement)
2 cubes auto, 8 cubes vault, 8-10 cubes switch @ 2 x per cube
Rb1 & RB2 on shelf
|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||
(Review comment: Thought the plan was this does not fire at all and acts as an "air spring"?)
2 cubes auto, 8 cubes vault, 8-10 cubes switch
RB1 & RB2 on shelf
(One cylinder per platform/ramp but they are plumbed together on same solenoid)
Hold/Release ramp system. Extend = hold ramps up
Retract = release ramps to ground level
Bimba 061.5-DXDE 7/8" bore, 1.5" stroke
Double acting, double ended
Starts match under pressure
Modifying mounting to use 3/4" bore, 2" stroke double acting on hand. Will cut off 1/4" pf threaded end and grind down remaining threads.
RB1 & RB2 on shelf.
Consider we may not need to start match under pressure - all loads lateral.
|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||Limit Switch||Tripped at end of travel/at hard stop on front of robot||Left side A-frame top front|
|Arm||Limit Switch||Tripped at end of travel/at hard stop on back of robot||Left side A-frame top back|
|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
|4 total, 1 on each jack - Sensor should be at output stage of each gearbox|
|Ramp||To be Determined||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|
Visual feedback for lining up with exchange?
MS LifeCam HD USB camera
|On the back left corner of the robot in the area set aside in cad|