How much planning goes into your robot?
 

I was thinking about how many factors can affect the performance of a robot in another thread, and I began to wonder how much planning other teams actually do in the creation of the robot. By planning I actually mean two categories: Calculations and Drafting.

Drafting: Whether it be hand-drawn or computer-aided, accuracy is key in creating a robot that operates efficiently. How many teams just "wing it" and do barely any drawings? How many teams only draft key features such as drive components? How many teams draw their entire robot up before a single component is built?

If you just draw pictures of your robot without any specific numbers to them, you'd fall under "No Drawings". Drafting involves dimensions. Every team most likely draws pictures of how their robot should look.

Bottom Line: Say if your robot spontaneously blew up at regionals (Hey - It could happen). If you could send the CAD drawing to a professional machine shop, and they could build your robot (before any "tweaking") without you telling them a thing, then it's extreme.



Calculations: A lot of equations fall into the design of a robot. Not matter what, you will use them. However, how many of them you use is up to you. How many teams calculate very little (teams that used FIRSTs stock drivetrain would most likely fall here) and just wing it based on personal knowledge? How many teams factor a moderate amount of calculations in designing their robot? How many teams have done extensive calculations in their robot design?

For example, if you are creating a shifting robot and you want, on a low end, a high-torque robot, and, on a high end, the fastest robot you can get without tripping breakers, what do you gear the high speed to? Well, if we look at the breaker spec sheets, you can draw 4 times the rated current for 1 second before they trip. You can draw 2 times the rated current for 5-8 seconds before they trip. Now, if you're pessimistic, and you say your robot is 70kg (~140lb), you can calculate how long it will take your robot to accelerate using the equation:
Torque = (Moment of Inertia) * (Angular Acceleration)
where
Moment of Inertia = robot weight * (overall gear ratio * motor shaft radius)^2
Now, you can generally say that current consumption for a torque at 120A should decrease to 80A within 1 second, and that the torque for 80A to 40A should decrease within 5 seconds. I've skipped a lot of steps here, but eventually you'll end up with a differential equation that's equal to the minimum gear ratio you could use.

I would consider this the "extensive calculations" category. I guess this goes hand-in-hand with robot complexity. A standard drivetrain doesn't require very many. All you need to do is decide whether you want high-torque or high-speed and qualitatively analyze the motor-torque curve. Then just pick out a good gear ratio.

Bottom Line: If your calculations could be performed (or were) by a standard high school Physics student, then you'd fall under the moderate category (High School level math). If your calculations required special knowledge in Calculus (such as my example), Materials Science, Thermodynamics, Electrical Engineering (College-Level Stuff), then I'd consider it extreme.

Check all that apply. If you weren't responsible for designing AND/OR you weren't responsible for calculations, please don't vote (or vote for #7) so you don't mess up the results.


As for my old team, 93, we had a rule that "everything must be drafted before it is built". On the calculations side of things, we'd fall under "moderate". Overall, the gear ratio was done right, according to current constraints, but not to the level of optimizations in my example.

TechnoKats 45
 

If I could have voted for two items it would have definetly have been extreme for both of them. Andy Baker (who is the MAN at doing CAD) draws everything in UG and prints it off to be made. You may have even seen our print book at some of the events in previous years. Another cool thing that Andy does is print off full scale or 1/2 scale prints of assemblies on the robot. I can remember in 2002 when we had an full size print of the drive base and I used it to align the gearboxes. For calculations I'de also have to say we are extreme. Everyone is always doing calculations, and there are 3 engineers on our team that do an extreme amount of it (Andy, Mark, Steve).

I did post-production drafting of the entire robot (as it was being built). We didn't have any CAD models to work off, we had hand sketches. Being that we used extruded aluminum, we safeguarded just about everything by making sure it's function could be slid a few inches an whatever direction to work right. Our only problem? Our Tape Measure said 36".. FIRST's said "36 1/4".. Answer: Portable bandsaw.

Calculations were done mostly for our gearbox and finding a desired Torque vs Speed since we did not shift gears. Past that, finding the correct point to mount our pnuematics for our 15lb downward dropping wings to fall to a horizontal and still be able to come back up.

This is an interesting thread, because i have the same questions. I know that many teams do very little drawings, and I have noticed that sometimes there success rate is lower then the teams that do many drawings and calculations. I have also seen that if you spend to much times on calculations you sometimes do not have enough time to get the robot done. There was a team that i met at the national event that had a very well desiged plan, but when they tried to implement the plan, it did not wuite work the way they wanted it to. It turned out that at this teams first regional they did rather poorly, and made many changes before the second regional event. In the end they were a low rider, which everyone knows was an important factor in this game this year. I believe that sometimes teams need to look at the big picture before they build. I also think that brainstorming is important. FIRST wants you to figure out how to play the game, and how to play it more effectivly then the other teams. I always say that the more ideas you have the more effective you're chances of winning are. I hope to see you all again next year.

Our level of detail depends largely on the criticallity of the system.

We did do calculations to determine the gear ratios for the drive, but didn't do extremely detailed drawings of the skyway wheels or the drive sprockets. These items were roughed in on the overall assembly, but we didn't figure out exactly where everything was going before starting to build. There were "keep out" zones on our overall assebly drawing to cover this. Besides you don't want anything important in the drive bay near the chain anyway. To much risk it will get damaged by the chain if something bad happens.

On the other hand, our ramp gripping arms were completely modeled, including the motion, before we built anything. In fact we used the CAD drawings as patterns for the linkage parts when we built them. Our box gripper and lifting arm were also modeled and checked using FEA before being built.

Our drive motor mounts and the gearbox for our arm were mostly done in CAD before we built them. I say mostly because Rick Varnum, our machinist, (who is probably lurking out there somewhere) decided we needed to lighten up the sides of the gear box so he used a CAM program to generate an NC program for that. It took less time than adding the pockets in Inventor. Besides the pockets were not critical to the function of the gearbox or any mating features.

On the other hand, our "light lifter" which kept our light from being bashed on the bar, was built on-the-fly and never has been documented.

Over all, I think we did more layout and planning this year than ever before. We also placed higher than ever before.

A coincidence?

Hand Sketches are still considered drafting if they have numbers on them. Just as long as you include dimensions of how long a part is supposed to be, it doesn't matter how it looks freehand. If you have a circle cut out of an aluminum plate, you should have the length, width, distance of the circle center from the corner (x,y), and the radius of the circle. If you had those 4 things, a machine shop could replicate that part. I'd consider that extreme, but only if the entire robot was drawn up.

I think that every tobot needs some planning. I really don't think it would even be possible without some planning. There are so many parts of a robot, and the drive train must be carefully planned before construction can begin. I have gotten the chance to talk to a lot of rookie teams this year, and many of them plan more then even championship teams do.

Good Luck to everyone this year at the invatationals. See you guys next year.

Well of course everyone has some planning.. nobody just starts building without telling others what is about to be cut and why with reasons.

Some teams just don't have the resources to make CAD/Inventor mockups of parts in the time needed. Sometimes a little trial and error can be faster than Calculate, Dimension, ReCalculate, Assemble.

Now, a question for the teams who voted extreme:

If you voted extreme for drafting, why did you feel the need to create accurate drawings of all robot components? Did it make the build process easier?

If you voted extreme for calculations, what did you use the equations on/from? If you voted here because of a custom circuit, no need to answer (although you're in the correct category).


I'm trying to get a survey of how competitive it has become. In general it seems that teams are sticking to High School level stuff. I'd venture that a few teams would fall under extreme for both categories, such as 45 and 111, who may have used differential equations in calculating gear ratios, or used special knowledge to create a custom circuit.

We spent two weeks brainstorming and cadding our ideas. We made every nut and bolt on the robot and had everything just as it would be on the bot. It helped oh so much when we had to send out parts to be made b/c the ppl could look at the sketch and know what they were doing. It may be tedious work, but it is definitely worth it to spend the time making every part--it saves a lot of time and chaos in the end. We even had our bot finished like five days BEFORE we shipped this year!! That never happens. We were able to practice with it, which definitely helped.

Re: How much planning goes into your robot?
 

I'd Assume a lot of planning goes into every teams robot. Its kind of like the famous saying...measure twice cut once. You've got to go over and over on everything to make sure you're on the right track, then you put all your ideas into the actualy building of the bot.

Re: How much planning goes into your robot?
 

We don't usually spend a lot of time drafting, but we model with cardboard. After the robot is built with cardboard, we draw up dimesioned drawings and go from there.

Re: How much planning goes into your robot?
 

We CADed the frame, the Gearboxes, and I have at least 30 pages of notes(typed, CADed, written, or scribbled) detailing our autonomous system. We did calculations for the drivetrain, and manipulators. Everythign has at least a sketch. There are probably manipulator CAD drawings, but that's not really my part of the robot. I guess our team would fall under moderate calculations, and moderate draftings category. We don't have a cad model down to the last bolt of our robot, but we are doing ok.

Re: How much planning goes into your robot?
 

Our team in the past has had sketches and ideas, with a FEW drawing with numbers that disapeared somewhere after the design decision making was over with. This year, we handled things a bit different, making cardboard models of the robot, and I've been marking everythign about the drive train out on paper, running whatever math I can (trig) and using a pencil and calculator like a madman making sure everything works and all that.

Re: How much planning goes into your robot?
 

Planning?!! Boy our team went from one end of the spectrum to the other from 03 to 04. in 03, every piece of our bot was drafted before it was built. In 04, we were working off napkin sketches and our imaginations. If something dont work right you redo it. As for calculations, we did some but they went largely ignored until we found out we had problems. The main problem there was switching from drill motors with stock gearbox to chippewa motors with no gearbox. wild guesses don't cover that very well

Re: How much planning goes into your robot?
 

This year, 45 had like 4 or 5 sub-groups. They all stayed apart for a week and we presented a prototype made of like cardboard at the end of the first week. Then, Andy combined all of em' into one basically, he also added his own ideas in. This year that method worked out really great for us. :D

-Kyle

Re: How much planning goes into your robot?
 

Well, this is somewhat correct.

We do split into 4 different design teams for 5 days. At the end of this time, we get together and each team presents their concept and how to play the game. We highlight the ideas we, as a team, like the most. Then, we sleep on these ideas for a day. The next day, we get together and choose an overall design, as a team.

We took one design team's idea (Austin and Steve Butler's group), and then added a "funnel" idea from the group I was on. We knew that if the funnel design did not work, the fall-back plan was a ball-collecting robot with a great arm.

(it was definitely not my idea... it was a team decision this year)

Andy B.

Re: How much planning goes into your robot?
 

We do everything for our robot from the second kickoff ends to the final day of shipoff's :D

And we do it moderately-extremely (no inbetween, all well).

Re: How much planning goes into your robot?
 

We also split up into design sub-groups for about a week after kickoff. About a week and a half in, we present prototypes to the combined group, make adjustments to calculations for a few days after that so that each part fits. We attempt to CAD it out, but most times we just have really specific drawings on paper of each system. Then build begins (trumpets sounding in the background)!

Re: How much planning goes into your robot?
 

Our team drafts and calculates everything to the smallest hole. It is definitely why our robots are usually good every year. Even if we make design changes, or anything, we CAD draw it first, do the calculations and then make changes. The main people behind this is our Bristol Myers tradesmen, we learn a huge load from them. They are truly unique people.

Re: How much planning goes into your robot?
 

we created a lego model, agreed it was a good design, and built... built= measure...cut...fit...(if it doesnt fit, cut again or file)...get next piece...repeat...overweight? ..drill....drill....drill.....drill.... :D

Re: How much planning goes into your robot?
 

a good amount goes into the planning of our bots-- we just sit for about the first few days and decided what we want to our bot to do-- we take in the consideration of what he have available-- i believe that's a key thing-- then students come up ideas along w/ our mentors-- from there we just vote on designs and concepts--and eventually the engineers draw out the simple designs the students have come up with on the blackboard or the overhead sheets

plannning is somethign that all teams should do-- good luck with all the planning next season

Re: How much planning goes into your robot?
 

as much time as in takes. most a week.

Re: How much planning goes into your robot?
 

We spent the first week and a half building the playing field and coming up with different designs for the robot. Then we came up with a final idea and drew it out and wrote in the different measurements we would need to make everything work their best. We then dry-fitted peices and measured and cut. I put medium for drafting, but minimal for the calculations.

Re: How much planning goes into your robot?
 

We make solid models and detailed drawings of every part on the robot, including kit parts. This makes our assembly actually assemble without having to widen holes, remake parts when interferences are discovered.

In 2003, the came in very useful when the drive key ways in our primary drive shaft started to fail. We got some material, printed out the drawings and submitted them to the shop. We had replacement parts ready before the key ways actually failed.

This past year, one of our high school students learned enough to be able to make our engineering drawings based on the models which we uploaded on our message board. He prepared a design notebook with every part on the robot, material, how much it cost, etc. It was an impressive piece of work, and he really knew how to make engineering drawings by the end.

Since we have something like 400 different parts on our robots, that's a lot of drawings.

Re: How much planning goes into your robot?
 

Hey, I feel slighted. There's nothing in the thread so far about software. :p

This year was different for the TechnoKats in a couple of ways. First, the programming language changed, so none of the previous code was usable. Second, the usual programming mentor was called away on business just when things needed to get started, and I got asked to try to take charge.

With no prior experience with FIRST robotics, and no idea how programming the InnovationFirst system worked, I said yes anyway. I started by planning what I thought was a reasonable software architecture, with the control algorithms decoupled from the actual I/O, having separate bits of code dedicated to mediating between internal program states and the sensors and actuators. It turned out to match what was possible with the system very well. A couple of weeks later, everything was mapped out and most of it looked like it was going to be easy to make work. By the time the robot's motors were wired up, the software was ready to run.

The advance planning paid off again when it came time to implement the autonomous code. The architecture had been designed to make it easy to deal with both manual control and programmed sequences, and it turned out to work that way in practice.

Now that I know my way around the IDE and this year's default code better, I intend to make use of separate source code files better next year. I've already begun sketching out a more easily configurable PID control routine, and I'll probably be working with a couple of students this fall to prototype a motor/feedback package so we can experiment with it.

Re: How much planning goes into your robot?
 

I tried doing the same thing, but didn't start early enough and didn't get it tweaked enough.

Inside Sparky 384
 

Here at the Sparky 384 HQ, we have learned one thing well: planning helps prevent frustration, prevents relationships from breaking up, and also prevents those late night runs to Walgreen's for PeptoBismo.

At Sparky, we use a highly evolved form of decision making that not only makes the leaders lives easier, but also prevents one person from being targeted for an idea that didn't pan out at the competition. It's called a "survey". This "survey" helps us discover what our team wants in a robot.

After the patent pending "survey", we then go to the drawing boards (aka Clark's Office) to draw up plans. We are never done. As long as the robot isn't in the crate and off to FedEx, there is still time for changes. While this is a blessing, we have limited it's curse part by freezing certain parts of the design, such as the drive system and others.

Re: How much planning goes into your robot?
 

Is there a book/web site/white paper that you know of that discusses in more detail on how "eventually you'll end up with a differential equation", something that I can use to explain these complex calculations in lame terms for my team?

Thanks
Adrian

Re: How much planning goes into your robot?
 

we normally draw up the essentials of the drive train and just go hacking away at the end effect. setup an end effect test it out, works - keep it, doesn't work - throw it out....start again.....make for a very proficient end effect, but gives little time for the drive train to be developed so we need to have the final drive train on the floor in very little time....

We normally know where we want to end up with our machine right after the kickoff weekend, but getting there is a little more tricky....

Re: How much planning goes into your robot?
 

I would say we've done a great deal of drawings for arm design concepts. Some have tentative measurements some have none and some are competely to scale.
As for calculations they exist to make us change our arm design.

Our design process has gone something like this:

Draw a concept design of the arm
Redraw it with angle and length measurements
calculate torque etc.
redesign arm
repeat

Re: How much planning goes into your robot?
 

A lot of our planning includes breaking into smaller teams and each creating a different prototype, then all getting together and putting all our ideas together to make one great robot. But we really try hard to do lots of calculations to get it all as accurate as possible.

Re: How much planning goes into your robot?
 

a lot

Re: How much planning goes into your robot?
 

We were supposed to plan a robot???! aw man, we were building a time machne!!!!!! ;-)

Re: How much planning goes into your robot?
 

We work with NASA programmers, engineers, and machinists out at the KSC Prototype Lab, so even though our students do a lot of the calculations and drafting, i'd consider them both to be at the Extreme level.

Roccobot is completely designed from top to bottom and everything inbetween in a program called Pro-Engineering, or Pro-E for short. (its kind of like CADD for those of you who know what that is... essentially, we build a complete three-dimensional model to an extremely accurate scale on this program before we even think of going to the machine shop) We know exactly how the robot looks and pretty much how it will work before we even think of taking a sheet of aluminum to the watercutter.

Just because we arent allowed to use the machinery out at NASA (due to liability issues) does not mean that our mentors build our robots for us. Although techinically they machine each unique part for us, we students are the ones who work on Pro-E and actually design the robot first. Then a mentor will look over what we've done, and together both the students and mentors will work to achieve perfection. If we machine something and it doesnt work, we go back to the drawing board and try again, but our goal is to never have to do something all over again. [Six weeks is not long enough, and we do not want to waste time by having to rework calculations just because something was off by five millimeters. We want to ensure that we conserve as much time as possible, so that our drivers can at least get a little practice time in before we ship the robot.] After each part is made, the members of our pit crew actually assemble to robot themselves, with very little if any aid from mentors, only using the Pro-E blueprints that we've printed out. This way, everyone on the pit crew knows exactly what goes where and how it all works, just in case something stops functioning after a match.

It's a lot of work, but its worth it. :yikes:

Re: How much planning goes into your robot?
 

We're hoping to get electricity run to our build shop before next season starts...

Re: How much planning goes into your robot?
 

Going into the 4th week we are still planning things and trying to cooperate with our one sponsoir that dropped us and wont make parts, and one company that said they could make our parts is not going to be able to. So I think we are about at the standar time we are usually at. Not being able to start working on the robot till the staart of the fourth week.

Re: How much planning goes into your robot?
 

not enough

Re: How much planning goes into your robot?
 

We're 3 weeks in... and still designing! They say we'll finish CADing tonight...

probibly...

hopefully...

maybe?...

Ah screw it, it ain't happening! :D

Re: How much planning goes into your robot?
 

oh, we've drawn up several designs of different parts, debated pros and cons of everything. We have a couple of really good drawings that sprang from thin air at 2:00AM. But so far, all we've done is planning. :ahh: :ahh: :ahh:

Re: How much planning goes into your robot?
 

Well... It all depends on which team I've worked with that we're talking about.

Some of my old teams have sponsors that have their own methods,
that range from a mix of student/sponsor design to students
stating WHAT they want the robot to do, and the sponsors then
fully design a machine for them to manufacture. I'll let them
speak for themselves.

Now as for "my teams" (the few I'm working with the most), I've
provided a "Formal Game Analysis" method to help the *students*
mathematically figure out what designs will work, and what probably
won't. It looks at a game and *suggests* a range of *possible*
tactics and bot designs. (BTW, what it suggested for THIS year
blew even ME away!). I could talk about that method, but that's
a whole separate thread, and not relevant at this point of the season.

Anyway, one way or another we're left with a set of PRIORITIZED GOALS
for the machine, AND the overall machine's concept.

Next, **THE BIG RULE: "Machine Goals will be accomplished in PRIORITY
ORDER". Resources ($$, people, matl's, weight allowance, etc.) shall
be shunted from lower goals to achieve higher, as needed."** No
sense building something that won't accomplish your #1 goal!

Ex: A few years ago, we had: #1 as "Grab Small Balls", and #4 as
"Handle Big Ball".Well, during design the Big Ball Arm got in the
way of the small ball collector, so it was dropped!

We next make the goals CONCRETE, and PRIORITIZE them.
Ex: We don't say "It'll score a lot". Instead, concrete actions,
speeds, and times within the round are all defined. For example:
"In Auto Mode, the machine shall take no longer than <xx> seconds
to <move to this position> <do THAT> (or whatever)."
That's pretty specific! Of course with a 10 sec auto mode
this THEN suggests that "In Auto Mode, the PAYLOAD must
require no longer than (10-xx) sec to <do ITS specific thing>", etc.
We then do this for ALL actions, at ALL points throughout the game.

This yields a VERY specific set of performance specs for the machine,
but does NOT say HOW they should be accomplished.


At this point, my teams diverge again...


Some of my old teams then use "Centralized Design". The entire thing
is worked out in ALL detail. CAD drawings are made, etc. The build
now progresses like a manufacturing plant. Yea, this works well for
some teams, and their sponsor's philosophy. The design is well controlled,
Production management tools can be employed, etc.

But if you have TOO much of that, I've found it hard to get anyone to show
up to BUILD it! If for any reason they haven't felt a part of the decision
process (which often happens if you decide AGAINST their "favorite design")
they may even *abandon* the project because now they are ONLY
"labor for someone else's machine". (Hmmm...)


My current team uses a DIFFERENT philosophy. We let the SUBGROUPS
make ALL the manufacturing decisions for THEIR part of the problem,
DURING the build. After all, they are the ones that have to make it
work, they already have a very specific set of design goals in hand
it MUST accomplish, and a manufacturing timetable to meet.

So let's say for example Drivetrain decides to choose a walker bot
over a tank. Our rule: If it can meet ALL of the design specs we
laid out (including time, weight and size allocated to it) AND it can
be made to work in time, GO FOR IT!

This isn't without its own challenges... We often have some verrrrry
nervous mentors! But we HAVE "local" mentors in each subgroup to
keep an eye on it. You also don't KNOW exactly what you'll end up
with when they start!

But the advantages are many:

1) We get to building sooner. Once the spec is in place, they GO.
2) It challenges the students. All of the problems have NOT been worked
out when they begin. They have to THINK, and there are many
opportunities to teach them about how to solve something.
3) It encourages "creative problem solving" on the fly. Some VERY cool
stuff has come out of groups to cure certain problems encountered.
4) The design isn't "fixed in stone". If one thing won't work, the local
subgroup has the AUTHORITY to change things, whenever needed.
For example: If Drivetrain's "super delux 27 wheel drive" they're
attempting is overweight, won't work, or parts aren't available for it,
AND a basic two wheel two castor drive WILL, Drivetrain group is
FREE to change it in the MIDDLE of the build, as long as it won't
affect the STRATEGY of the bot.
5) We're free to EXPERIMENT. A subgroup that's ahead of schedule
may decide to try another thing, to see if that will work BETTER.
(...and if it DOES work better, use THAT instead!)

But really, HALF the fun of this method is we DON'T know what the bot
it'll LOOK like, until we're done. Yes, we know what it will DO, and
when it'll be READY, but the final form is VERY mutable during the build.
Also, we all often drop and run over to look when someone comes up with
something REALLY cool, which means you don't want to miss ANY build sessions!

But the best part is that when you're done, EVERYONE feels ownership.
You each know that YOUR decisions made during the build contributed
to <this> or <that> ability of the final robot.

Now don't get me wrong... I'm not knocking Super-CAD/CAE driven teams
at all! Testing a design on a CAE system REALLY helps! And if you
have way too large of a student/mentor ratio, having a huge work
plan predefined helps. People can just come back when they need
more work, and grab "Task #27" off the queue. VERY efficient.

But if you don't have a lot of CAD/CAE expertise on hand, giving
everyone the freedom to make LOCAL decisions DURING manufacturing
DOES work, and may even get you off the starting block a bit sooner.

Now IMO, the KEYS for ANY build method are having:
- WELL DEFINED GOALS for the robot to accomplish;
- A good work schedule defined up front that they MUST meet;
- Make sure everyone has the RESOURCES to accomplish (training,
matl, money, mentors, etc.);
- Someone in EACH group responsible for keeping an eye on the
schedule (no getting caught in trivia, we have a schedule to meet!);
- Having the GUTS to drop one line of research for another, if needed;
- GOOD COMMUNICATIONS, so everyone knows the status - between
all subgroups, students/mentors, teams and sponsor's locations,
team and school, etc.

Does that answer your question?

I hope this helps!

- Keith

Re: How much planning goes into your robot?
 

We are a very detailed oreinted team. Partially because we wnat to make sure every aspect of the robot is built right and also to make sure that our kids are involved in the process so they actually learn from the experience instead of just showing up one day and BAM!- there a completed robot sitting in the shop one day after brainstorming.
We communicate with the CAD team and the sub team contribute their design ideas to the CAD team and the robot is constantly weighed.
I can't really see how slapping the robot together really works. Wasn't there a team last year that said they showed up to a cometition at 157 lbs or something like that. Precise planning helps to avoid disaters like that.