Spectrum 3847, the St. Agnes and Strake Jesuit engineering team, was the recipient of the prestigious Quality Award at the FIRST FRC (For Inspiration and Recognition of Science and Technology) and a Regional Finalist at the Lone Star Central Regional Tournament held at Strake Jesuit College Preparatory.
“We are honored to have received the Quality Award sponsored by Motorola Foundation. The award celebrates machine robustness in concept and fabrication. Our robot Gamma was built with a very detailed plan in mind to withstand the rigors of competition. FRC is often called the “the hardest fun you’ll ever have. ” said Spectrum 3847 Coach/Mentor Allen Gregory. “In addition, the team won the Engineering Inspiration Award at an earlier tournament and came away with a berth in the 2017 FIRST World Championship. We look forward to the global competition George R. Brown Convention Center in Houston from April 19 to 22, 2017.”
Spectrum 3847 was ranked 3 with a record of 12-5-0 and advanced to the finals in an alliance with AwtyBots #5829 and Screaming Chickens #3997. They formed a strong alliance and worked their way to the finals. They lost the finals to three award winning teams Robonauts #118, Texas Torque #1477 and TCAT #5526. All six teams will join the global competition at the Championships in April.
Spectrum 3847 won the Engineering Inspiration Award and came away with a berth in the 2017 FIRST World Championship which will be held in Houston at the George R. Brown Convention Center from April 19 to 22, 2017
In addition to the Engineering Inspiration Award, Spectrum was also Regional Finalist at the HUB City Regional in Lubbock. They were chosen by the #2 alliance captain #1477 Texas Torque from the Woodlands, TX and to be the 2nd robot on their alliance. They then picked #159 Alpine Robotics from Fort Collins, CO. They formed a strong alliance and worked their way to the finals.
So we had a bit of break but we'll try to keep things updated as we move through the competition season.
Here is the state of the competition robot that we bagged. We didn't really get to perform a full system check on it but we are confident the subsystems work.
We are very pleased with the state of the gear intake. We have the control system working on it so their automatic gear pick up routines that lower the gear intake, spin the intake wheels and pickup the intake once the driver drives it into a gear. We were looking into using an IR proximity sensor to determine when we had a gear but it was having some difficulty getting tuned to the right distance so instead we realized we could just determine when the roller starts drawing more current which means the gear is fully back to the roller so the motor become the sensor. We are also adding some protective Lexan to stop the gear intake from damaging itself. We are also adding some additional roller tube to the intake that allows us to intake the gear when it comes in further to the side of the intake.
Build doesn't end
The competition robot may be in the bag but build season isn't over. We will continue to iterate on our design for the next 8 weeks until Houston Champs.
“Engineering is a great profession. There is the satisfaction of watching a figment of the imagination emerge through the aid of science to a plan on paper. Then it moves to realization in stone or metal or energy. Then it brings homes to men or women. Then it elevates the standard of living and adds to the comforts of life. This is the engineer's high privilege.” - Herbert Hoover
We are still working on getting our parts ready for the sheet metal delivery.
We have our gears and wheel modules ready to be bolted up to the sheet metal when it arrives.
We also have powder coated Versaplanties for the competition robot ready to go as well.
“The implication of this might surprise you, though: when the tough parts come along, the rejection and the slog and the unfair bad breaks, it makes sense to welcome them. Instead of cursing or fearing the down moments, understand that they mean you've chosen reality, not some unsustainable fantasy. It means that you're doing worthwhile, difficult work, not merely amusing yourself.” - Seth Godin
Now that sheet metal has been sent out, it's finally time for us to buckle down and figure out some of the smaller parts on our robot. Among these smaller parts is the plate we plan on using to cut off individual lanes in our three-wide shooter.
CAD model for said plate
Our plan for actuating this plate was to have it driven by a REV Smart Servo mounted in the inside of our shooter tower via a rack and pinion. This seemingly simple task proved to be the cause of numerous attempts to fix open contours in Solidworks before realizing that rack teeth do not, in fact, use the same profile as gears and are simply trapezoids. With the annoying geometry problem out of the way, the question then arose of how to know what dimensions define these trapezoids. The annoyance was further exacerbated by REV's use of the metric module to define their tooth spacing instead of the diametrical pitch more commonly used in the imperial world.
After a number of google searches (including re-learning what such technical terms as "diametrical pitch" even mean), we eventually discovered a useful whitepaper on the Iowa State University website which outlines how to design gear and rack teeth given certain parameters for your tooth profile. After copying their spreadsheet maths into our Master Sheet, we were able to successfully model our rack. A copy of our spreadsheet can be downloaded here.
Sample spreadsheet outputs for REV Smart Servo pinion
The rack tooth designed from the above spreadsheet data
Closeup of rack and pinion
-Will S, Spectrum
"I must not fear.
Fear is the mind-killer.
Fear is the little-death that brings total obliteration.
I will face my fear.
I will permit it to pass over me and through me.
And when it has gone past I will turn the inner eye to see its path.
Where the fear has gone there will be nothing. Only I will remain." - Frank Herbert