Saturday, January 12th, Week 1
We split everyone up based on the three main mechanisms: Arm, Intake (including hatch and cargo), and Climb. The drivetrain still has a subgroup but does not have any official members.
Drivetrain
The bellypan and 1″x0.5″ support bars were added to mount the battery box. An electrical panel was put together and pneumatics were all hooked up. We actually got it driving today!
Here is a link to it driving around: https://photos.app.goo.gl/92petM7EvKDq8dkN7
Still needs to be tested on drivetrain:
- Center drop – Is current 3/16th-inch center drop good or is it too aggressive for driving? Would 1/16th or 1/8th be better?
- Pushing power- test pushing other robots/ other robots pushing us.
- Automatic (program a button) to switch between high and low gear.
Arm
Preliminary design steps: determine ideal gear ratios, choose best gearbox(es) for the job, figure out mounting and space in robot.
Based on the approximate weight and length of our arm (20 lbs, 25 inches) we found that a 140:1 gear ratio, or around that, would be ideal.
Though a custom gearbox was our favorite, and probably would end up being the best option, we realistically took into consideration how we would fabricate it, and our lack of experience (and everything that entails – cost, time, etc). After all of the pros and cons, we decided on this VexPro gearbox: https://www.vexrobotics.com/vexpro/motion/gearboxes/single-speed-single-reduction.html#CAD_Files with a 7:1 (single stage) ratio.
We will use 3 mini cims to decrease current draw.
Combining this COTS gearbox with a 7:1 Versa Planetary stage, and a stage of 38:12 sprockets, we can get a 155.17:1 ratio but also have the option to play around a little by changing sprocket sizes.
Next, we concept sketched, a lot.
Next steps are:
- Designing the super structure
- Designing mounting brackets (shoulders and plates)
- Making gearbox modifications in CAD (plates and VP additions)
- Mounting gearbox in robot (spacing)
Intake
We decided to continue working towards two designs:
- A top and bottom roller intake in which the rollers flip back to pick up hatches. Much more complicated design.
- A top intake that only works on one side of the robot, but can outtake on both sides. Much less complicated design.
We came up with the crazy idea to put velcro on our wheels to see if it would be possible to use our wheels to pick up a hatch panel. It did not affect how the ball is picked up from the floor (see in videos) so we will continue messing around with the idea.
Link to proof of concept testing: https://photos.app.goo.gl/3KEnWvkBm7FFFRoQA
Next steps are: CAD both prototypes
Climb
Our climbing group tested out their pistons today, which worked really well. They also made some delrin blocks to act as skis under our robot.
Link to Pistons Lifting Front of Robot Testing: https://photos.app.goo.gl/cVoC5rJJS1tcmqSt6
Next Steps: Find space in robot for pistons, determine which pistons would be best, testing different “ski” prototypes, OR testing/ designing different ways to get onto the second platform level.
Metrobots Build Blog 2019 
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