Category Archives: Team JVN

Team JVN: Turning a Setback into an Iteration

In a typical 6 week FRC build season, every team navigates ups and downs with a nearly unparalleled intensity. Saturday night (well, Sunday morning), Team JVN experienced one such roller coaster. Around 2 am, BJC and Jay finished what was thought to be the final intake roller assembly. Spirits were high – it had been a productive evening, and the prototype for this subsystem had worked flawlessly. Giddy with excitement (and sleep loss), the team mounted the intake to the prototype base, connected to a battery, and….

…the ball got stuck. Badly. “Pull it out, let’s try again.” Same result. For the past few hours, the team had been finishing up their individual portions, and were preparing to wind down for the night. Now they gathered around. “Pull it out. Try it again.” No dice. “Pull it out. Try rolling it in.” The same. A floor intake had been determined early on to be a crucial competitive feature – and an intake that doesn’t take in game objects is of little help.

The team gathered around the robot for a late night design review. After some tense back-and-forth, the decision was made to scrap it and start from scratch. It was around 3 AM, and that’s when something happened that defines and bonds competitive robotics teams. The team immediately split up and went to work, silently at first.

Randy and Charles started assembling the modular electronics panels. Aren was on a mission to finish the launcher arm and base. Jay and Carlos started disassembling the intake roller, and BJC went straight to CAD to figure out what went wrong and set up new geometry. All hands had come in for the “what do we do now” meeting, but after a direction was set, it was back to business as usual.

Getting disheartened and throwing your hands in the air amplifies the problem. Facing it head on helps productivity – if everyone tries to fix the roller, the electrical panel won’t get done. It helps morale – seeing Aren’s completed launcher assembly (that everyone had a hand in designing) was positively beautiful. But most of all, it helps retain forward momentum. When the team came back in Sunday morning, we had a completed launcher and a new design for an intake roller (that ended up being successful).

Every FRC team will experience moments such as this in their 6 week build season, many times even worse. But the teams that have the resolve to press forward, to learn from the mistake and use it as an iteration rather than a roadblock… those are the teams that will excel.

Team JVN: Aren’s “Sweet Spot”

Often, strategy is determined based off of scoring calculations, observations based on experience, or just plain gut feel. However, sometimes they come from something a bit more inspired.

One of the defining moments of Team JVN’s weekend was a calculation done by Aren Hill that we’re affectionately calling “Aren’s sweet spot.”

arenssweetspot

From the beginning, the team assumed that doing a “layup” motion from against the wall (or ~20″ back) would be the most effective way to consistently score in the high goal. It would be repeatedly testable and possible to replicate in match conditions, two things that are crucial for a basic robot design. A former robotics driver and drive coach, Aren wanted to see if there was a way he could make it even easier on the driver. A quick 2D “Crayola CAD” easily laid out the parabolic path a ball would take upon leaving the robot, and revealed something interesting. Since the goal opening is taller than the ball by one foot, the previous mentality that you need to shoot precisely to score from the field turns out to be somewhat false. The above image shows this path – the vertical line in the middle is the field wall, with an opening for the goal. As becomes apparent, if you peak your parabola just below the top of the goal, you actually have access to a very wide starting range to score from (87 inches, or 7.25 feet, in this example). Increasing the power of your shot makes the parabola shallower, widening that “sweet spot” starting range. At this point, the prototyping kicked into overdrive. We had the opportunity to go out to Greenville High School, where the Robowranglers had been building the practice field that they will use for this season. The prototype was pulled back from the wall about 7 feet, starting angle was raised, and surgical tubing was increased. In a word… success. http://www.youtube.com/watch?v=3s2Ivy6nH8k After seeing that, we never looked back. All future iteration served to refine that design and widen the applicable sweet spot. Tune in to the robot reveal at noon on Tuesday to see how we did!

Team JVN: The Power of Prototyping

Team JVN started out with a strategy session that went surprisingly quickly. Once we began analyzing the game, we realized that due to the nature of the game cycles, it is pretty easy to determine the possible flows a match can take. (Well, at least as far as we think!) We discovered that the highest scoring cycles all included some way to elevate the game balls, even if it’s only over the truss and not more complicated/difficult movement. We began talking about putting a launcher of some kind on the robot, perhaps something that can intake the balls from the floor; add in a catcher and you have an extremely robust scoring machine. It also means that you become an attractively versatile alliance partner, which is obviously desirable.

One of these all-in-one machines could truss or catch, score by launching into the high goals, pick up another ball without catching it in the air, and so on. Our team felt this was a good path and decided to move forward prototyping a launcher/catcher robot. A catapult-style launcher would fit in well with our initial intentions of planting our robot on the goal wall and doing a layup-type movement. The catcher component would help show how viable truss-catching actually is, and would give us a feel for the new 20″ outside perimeter rule for 2014.

Our first prototype, the catcher bot, was surprisingly large. It actually inspired our confidences in the ease of making something that could both catch effectively AND toss a ball to another catcher bot. Given the potential scoring importance of assists in this year’s game, this was a particularly important discovery for us. The second prototype, our catapult launcher, had a ball airborne within the first two hours of the build. This was also particularly confidence-inspiring for the team. We utilized an old 2005 kitbot chassis that we had laying around into the base for our robot. We sent team members Charles Wensel, Carlos Perez, and Randy Larsen on our first Home Depot run for some 2×4’s and used those to create a tower. We added VersaFrame parts for the arms, added surgical tubing for tensioning, and voila – our catapult was working like a charm. But all of that was just the beginning.

After the prototypes were complete, we began JVN’s favorite part – the iteration of our designs. Those on ChiefDelphi or that have worked with John over the years have heard his “Design is Iterative” mantra many, many times. And for good reason – it’s an incredibly important part of the design process. The subteam – and later, most other team members – spent the majority of their afternoon and evening testing the launcher, recording the results, and attempting to find the correlations. For example, we noted the direction the ball was launched (e.g., “ball launches straight up”). Then we tweaked the robot in some way, such as tilting the robot forward to simulate changing the hard stop position. We then recorded the results – “ball now launches more forward” – and repeated this process over and over to understand the launcher’s behavior. As we tested the launcher, the structure itself began to change. We began to change the parts of the robot that we felt might affect these key components, and eventually ended up creating a more versatile and adjustable robot overall. Specifically: adjustable peg lengths for the ball cradle, adjustable hard stop length, adjustable pivot point for positioning, adjustable pivot height, adjustable surgical tubing strength, adjustable starting angle for release, etc. When the robot changed, our results changed as well. Now our results were more like, “Launches straight up. Adjust nylon strap to change actual hard stop position. Now launches more forward.”

To understand the robot further, we changed only one variable at a time to really nail down the correlations between each variable and the final output. We kept it simple by using basic tools (such as a tape measure) to track and record how much a nylon strap needed to move, or an angle meter to record the starting angle, etc. This isn’t complicated to do, but so many teams get this wrong by not properly dedicating the time and effort to this task. Small prototyping efforts can yield hugely important results later in the build season. By being efficient in our prototyping processes (and by utilizing some cool maths that we’re referring to as “Aren’s Sweet Spot” that we’ll bring up in a later post), we had an extremely consistent high shooter robot by the end of evening. It appears the final robot will end up looking very similar to the prototype design since we were pleased with its overall performance. There’s still a lot ahead of us, not to mention a small mountain of CAD work. We’ll keep you updated!

Team JVN: Late Start

If you tune in right at noon today, you may notice that it looks like Team JVN isn’t jumping off as quickly as Team Copioli. The truth is, they’re not. As many of you know, John V-Neun is the Lead Engineer for FRC team 148, the Greenville HS Robowranglers.

He promised the students on 148 he would finish running kickoff with them, before jumping into Build Blitz with TeamJVN. The result of this promise, is that TeamJVN will spend a few hours with the students of Greenville High School following the typical Robowrangler process before starting on their own (stupidly fast) pace. Only a few hours left!

Team JVN: Goal Mapping

One technique which JVN likes to use early in a design process is something called a Goal Map. Goal Mapping is a technique used during brainstorming in which a team builds down from an over-all goal to the details required to achieve it. Team JVN discussed their Goal Map for Build Blitz — it starts with “Beat Team Copioli” and branches down to further and further levels of detail. After the game is unveiled, Team JVN will then add additional layers of detail to the map, based on the game specific ways they’ll achieve their goals.

Goal Mapping

Team JVN: Build Plan Questions

Some Questions about our Build Plans: Team JVN has received a few of questions related to what kind of robot we’re going to build. Obviously we don’t know what the robot is going to look like, since we don’t know what the game is. However we can answer a few of the questions we’ve been asked:

Q: Is your robot going to be “fully legal” for competition?
No, not completely. Our control system won’t be FRC legal, and our robot probably won’t have bumpers. We discussed the reasons why we’re holding this event in the first place. Build Blitz is an educational effort; we’re doing it because we think there are lessons to be learned from our efforts which will benefit FRC students everywhere. We think there are more powerful lessons we can teach teams during our 72-hours. There are lots of resource out there showing how to hook up the FRC control system, we don’t need to show that. Similarly the time spent building bumpers might be better spent on other activities… like sleeping. That said, if there is some mechanism required which would be heavily impacted by the bumpers — you can bet we’ll be throwing some on there pretty quickly.

Q: What control system are you going to use?
Unless the game has some aspect which specifically precludes it, we intend to use a VEX Cortex Microcontroller with the VEXnet Joystick and VEXnet 802.11 Wireless Link as the robot’s control system. http://www.vexrobotics.com/276-1604.html If the robot is so complex it requires two drivers, we’ll use the VEX Partner Joystick. http://www.vexrobotics.com/276-1891.html

Q: Will you be developing a 2014 “Drive in a Day” during the Build Blitz, similar to the one made in 2013?
We’re not sure. This certainly depends on what the game is. There’s a chance that TeamJVN will be using the 2013 Drive in a Day, as is, or it’s possible that we’ll make some small improvements to better suit the 2014 game… or it’s possible we’ll start over completely and design the 2014 version. No matter what we do, we’re going to make sure it is heavily documented.

If you have any more questions, send a message to @TeamJVN on Twitter!