2018:Robot Design Details
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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 PER TOM C. THIS MAY NEED TO BE UPSIZED AND IS NOT FINAL |
Yes | Yes | Yes | Yes | 60 PSI | ? | |
| Arm Brake | Extend = engage brake - spring actuated Retract = Disengage brake |
Bimba M-041-D. Magnetic 3/4" bore 1" stroke | No | Yes | Yes | Yes | 60 PSI | ? | |
| Hand on Arm | Extend = "close" hand, tighten on cube Retract = "open" hand, loosen grip on cube |
Bimba 042-DP. 3/4" bore 2" stroke | Yes | 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 | ||
| Arm | Potentiometer | Absolute rotation position of arm. Mounted on actual pivot/shaft. | ||
| Hand on Arm | Retro-reflective beam sensor | Sense cube all the way into hand | Mounting is important! Must "sideways" at the cube at the back; do NOT mount so it looks direct at back of cube | |
| Ramp | Integrated Versa Planetary Encoder | Sense travel and speed of lead screw on lift jacks One phase Sensor should be at output stage |
4 total, 1 on each jack | |
| Drive | Shaft encoders | Travel of robot drive base. Mount on center (traction) wheel shaft. One phase | ||
| Whole robot | Gyro | Sense rotation | Must be in center of robot away from excessive vibration sources |
