Posts Tagged ‘ nasa lab

Day 2: Drivetrain Design & Manufacturing

Today, at the lab, a group of team members met to continue designing the robot drivetrain and continue manufacturing bearing blocks.

Networking & Lab Improvements

We started by networking all of the upstairs computers at the lab together.  This will allow us to share printers before the computers.  We were able to connect all of these using a switch generously donated by our sponsor, Vivid-Hosting.  The networking will be completed tomorrow.

We also procured two power strips which were wired under the floor to provide power to two upstairs tables for laptops.  Previously, the lab did not have a good place for laptops to work.

Manufacturing

Manufacturing on the bearing blocks continued today.  Progress is being made and the manufacturing will continue into the next few days.

Design

Today, we discussed and decided on several key aspects of the drivetrain.

The first topic of discussion was wheel size.  Several team members brought up the idea that with such a flat game field, we could potentially go to wheels even smaller than 4″.  Although we quickly ruled out 3″ wheels due to lack of ground clearance (~1/4″ clearance), we were interested by the prospect of 3.5″ wheels which would lower our center of gravity slightly and could decrease drivetrain weight by more than one pound.  Furthermore, because less gear reduction is needed with smaller wheels, the weight of the spinning components could be decreased by up to 20%, leading to a potential significant increase in robot acceleration.  However, some team members had reservations due to the decreased ground clearance in the move from 4″ to 3.5″ wheels.

To come to a consensus, we created a weighted objective table to weight some of the pros and cons of each design.  After much deliberation, the table resulted in almost a tie so we continued to discuss.  In the end, it was decided that any problems caused by the decreased ground clearance (1/4″ lower) of the 3.5″ wheel system could be avoided so we decided to move forward with the lighter 3.5″ wheel design.  This caused the outer bearing blocks to need edits so that they would not interfere with the newer, smaller wheels.

Benefits of 3.5″ Wheels

  • Lower Center of Mass
  • Less Weight
  • Increased Acceleration
  • Smaller Gear Reduction Needed
  • Less material means less cost
Benefits of 4″ Wheels

  • More familiarity with the design
  • More ground clearance
  • Less Tread Wear

The second topic of discussion was robot speed.  After yesterday’s strategy session, the whole team was in agreement that having a fast and maneuverable robot would be key to successful performance in Logomotion.  After deciding on small, 3.5″ diameter wheels, we also knew that these smaller wheels would not require as large of a gear reduction as has been present in past robots.

With the ability for a smaller gear reduction, we started with our gear ratios from last year and worked with them to both speed up the robot and minimize the use of large gears to decrease robot mass and increase acceleration.  In the end, we found a set of ratios that we liked that will both allow for the fastest 254 robot ever built and for smaller and lighter gears while still maintaining a slower low gear.

Finalized gear ratios for the 2011 robot. Robot speeds are estimated for 3.5" wheels in ft/sec at 100% and 80% efficiency. The first line represents the common reduction. The second and third lines correspond to the secondary reductions for High and Low Gear.

Finally, today was our deadline to finalize the gearbox shafts to be sent out for manufacturing by sponsor Pacific Precision.  All four of the shafts were updated and finalized by a team of students.  All drawings were checked by team leaders and mentors and were sent to manufacturing.

The Day Before Kickoff

It’s the night before kickoff and what  a productive day it’s been.

The day started out with us ordering over 250lbs of Aluminum from Coast Aluminum in Hayward.  The metal will be used to construct the robots for Team 254 and Team 1868.  Although we don’t yet know the game and don’t know what the robots will look at, we are predicting that they will have metal frames, so we bought the material to build frames.  After it was ordered, EJ and Sunshine drove up to Hayward in a NASA truck to pick up the material.

At the lab, other team members worked to put together a final list of consumable lab supplies that NASA will purchase.  Most of the items on the list were ordered today and the remainder will be ordered over the weekend.

Also at NASA, several programmers from both the simulator group and the robot group were working on various tasks in preparation for the busy robot build period.

Finally, several students worked hard to put the finishing touches on the NASA lab to prepare it for build.  The couches were cleaned and brought back upstairs and the welding table was polished to remove rust.  The field was vacuumed and shelves were organized.

9 Hours Till Kickoff
Go Poofs!

Cleaning up the Lab

Today at the NASA lab, several students and mentors were working together to clean up the workspace and prepare for the build season.

The computer workstations upstairs were put together after the painting.  All of the wires were nicely ziptied and the process of software updates began.  In the next few days, we need to update all of the computers with current versions of SolidWorks and other crucial software.  Furthermore, we need to build a wired network at the lab so that we can share printers between the computers.  On the white boards, vinyl stickers were cut to label each teams’ white board.

Downstairs, Devastator was prepared to be removed from the NASA lab for semi-permanent storage at Bellarmine so that it can be used for team outreach events and demonstrations.  This freed up space under the south stairwell so that we were able to move the vertical bandsaw into its own cavity, improving the safety of the workspace.  We also spread out the sanding and grinding area and moved a wall-mounted shop vac out of the sheet metal area into the sanding and grinding area so dust and debris can be vaccumed up.

In the sheet metal and welding corner of the lab, work continued to prepare the area.  We re-arranged the extremely heavy equipment, putting the welder in a position so that its cord could reach the outlet and so that it is easily accessible.  To accommodate these changes, we had to slightly adjust the positioning of the sheet metal shear and break and move the large arbor press into the machine shop.

In the general work area, we continued cleaning and organization and also began resurfacing the workbenches so that they have nice, smooth surfaces to work on.

Everything is coming along great and we are very excited for the Saturday FRC kickoff.

Lab Floor Painting & Cleaning

Today, more team members met at the NASA lab to apply a second coat of paint to the floor on the upstairs mezzanine.  The newly painted surface looks great and we will move the furniture upstairs tomorrow once the paint dries.  Furthermore, we mopped and vacuumed the floor downstairs and organized the tool chest, the white shelves and the cabinet in the machine shop.

Lab Floor Painting

Today, several team members met at the NASA lab to paint the floor of the upstairs mezzanine.  Two weeks ago, we sanded the floor to remove the chipping paint and last week new paint was able to be purchased.  To prevent chipping, we are using a urethane-based industrial paint.  Tomorrow, we will meet again to apply a second coat of paint.