Things to Explore

Technical Technical Discussion
1

Hello, users of ChiefDelphi. I’d like to seek some advice.

In recent years, team 840 has been facing difficulties with faculty, fundraising, and member turnover that have been gradually chipping away at our capabilities as a team. This has led us to decide to skip competing in FRC this year, feeling that we’re simply not ready at this point. While this makes me very sad (especially being a senior this year), this is also an opportunity for our team for focus training and look into technical aspects of robotics that we haven’t had a chance to touch recently.

I’ve been compiling a list of possible things for us to explore (reproduced below), and I was wondering if any of you could offer additions to this list. This does not mean we’re definitely going to attempt every single item, but just to give us things to consider and a sense of direction for the coming semester.

Thank you.

Things to Explore:

  • six wheel drive
  • alternative drive (mecanum, swerve)
  • conveyors and ball magnets
  • pneumatics implementations
  • linear gears/rack and pinion system
  • arms/manipulators
  • alternative steering (971-style)
  • line tracking
  • target tracking (camera)
2

I would say a major emphasis on programming. Like just programming even if it has nothing to do with robotics. I always had the mentality of software first, analogous to the brains over brawn. Just keep them programming to solve more and more complex problems. An omni directional drive shall keep your programmers thinking, somehow make it true omnidirectional so there is no “front”. Now that is a mind blower, I haven’t achieved it when my mentor assigned that for me.

3

You can pick which side your front shall be. A robot has no front, and is only limited by its directions of travel, usually this lends to having two directions of motion which are labeled “front” and “back”, but really it makes no difference.

For example, we have a robot (from 2006) which has two “fronts”. You use one “front” to collect the balls, then press a button to change the “front” and shoot out of a different direction (Which one might call the “back” while collecting), but really it has two fronts. It does not matter in code.

But seriously, if you’ve never built a 6wd, it is a start.
If you seriously want to, a swerve can be advantageous (if you can learn to drive it, something most teams overlook), but it is very hard to build so I would not recommend it to a team who has not yet mastered a 6wd.

Conveyors and such: We generally use orange belts (I have no idea where they come from), and drive them with rollers. Sometimes we use flat, sometimes we use round. Ball manipulation is sometimes important to the game (09 and 06, for example), and it might be helpful to prototype, but it isn’t very complex (Mostly spinning drums, not much complex motion).

Linear racks and pinions: I haven’t seen these used a whole lot. Most linear systems use a drum and cable system, and those can be very tricky. If you like using linear elevator systems, this could be prototyped.

Manipulators: History has shown that classic roller claws work very well. Other options include pneumatic claws. These two are the most generic manipulators for handling odd game pieces.

Arms: These are fun. You get to do all kind of load and gear ratio calculations, then program it to not kill itself, be as fast as possible, have a little error as possible, and be awesome. These each require specific implementations in software, such as a basic PD/PID loop (You will almost certainly need D, and probably I too), and if you have multiple segments you can correct for error on a joint by compensating in the successive joints. Since the cRio has a lot of power, you can do realtime trig to determine the angle for each segment, then recalculate based on where the joints actually end up, correcting for error while keeping the target end point, for example, above a certain height. If you want to, you can also slide the end effector in and out while keeping it at a fixed height, and determine all of the angles on the fly.
See if you can design it to be as light as possible, remembering material selection and thickness (For example, .030 aluminum tube is a lot lighter than 1/8" aluminum box, and a whole lot lighter than 80/20).

I don’t think line tracking is useful. I have never seen it used successfully, and generally encoders and gyros can get you close enough.

Target tracking: See if you can do it without overloading the processor. Anyone can do it. It’s the great that can do it, while doing something else at the same time.

Pneumatics: Use them like any other actuator. They have two positions, if you need something in two positions (like an AndyMark shifter, for example), use pneumatics.

Things to add to the list:
New chassis designs. Do something you haven’t done before. Learn something. Build stuff. Have fun.

@davidthefat:
No matter how much brains you have, it doesn’t matter if you can’t move.

4

Stephen Hawking: Nuff’ Said.

Haha, dark humor aside, you do bring up a good point.

I also would suggest getting kids addicted to robotics, not too addicted that they are failing their classes, but to a certain degree. People do a better job in something they like than on what they don’t like. Yes its pretty obvious, but it does make a huge difference in anything. Emotions affect a human dramatically, passion is contagious, so it the lack of passion. People perform better when they are in a better mood and a little disappointment can cause a chain reaction in the team. I would say get the mentality and team work down first before getting into any technical stuff. You can have all the resources in the world but if your team is lacking fervor, teamwork or any motivation what so ever, nothing would be accomplished. Get all your goals written down on paper and how you as a team would reach those goals and start working towards them. Also keep in mind that Winning is not the only purpose of being in a team like this. Remember to have fun above all else, because I rather have fun and do mediocre than have lots of internal team problems and do fantastic in the competitions. Its a character and memory builder, not about winning trophies.

5

I’m remembering a quote along the lines of

"three most important things on a robot:

  1. drivetrain
  2. drivetrain
  3. drivetrain"

Mr. Bill Beatty

(not exact quote)

so drivetrain development should be at the top of your list IMHO

6

Mr. Bill speaks truth.

Also, if you have an army of drivetrains to play with, tweak, refine, program, and practice, you’ve got yourself a set of “showbots” to take to events. People get a kick out of just driving around a chassis. Have races, obstacle courses, get lots of hands on the controls. The more “laypeople” you have giving input on your design, the more you can refine them to make them driver-friendly an intuitive.
Later on down the line you can put a camera on one, a t-shirt shooter on another, a series of different manipulators. A good project to explore would be making your chasses in such a way that you can swap out manipulators - all with identical mounting systems, and an easy way to inform the robot what kind of manipulator it has.

One manipulator digs a small hole. Robot does this 10x in a line.
Another manipulator plants a seed. Robot does this 10x in a line.
The third manipulator fills the hole back in. Robot does this 10x in a line.
Finally, a manipulator waters the newly-planted seed. Robot does this 10x in a line.
Each time you swap out a manipulator, press a button to let the robot know what’s on it, and let it do its job.

7

Anthony,
There is nothing worse than an idle mind or hands. Have you considered something more in line with you current situation like FTC or Vex? It will keep what team you have together, working in a smaller, student oriented event. You need to keep the team up front in your school’s mind for travel, and room to work, advisors, etc. It will also give you a more formal meeting arena to keep discussing plans for next year.

Might I add, that I think you are ready to compete. You have had the experience of competing in the past which gives you a leg up on rookie teams just starting. You have built good robots in the past, don’t lose the momentum. You are facing some challenging obstacles but the rewards are great.

8

Al is wise. I know many in FRC that look down at these “little cheep” robots but having been involved in both FRC and VRC I have learned the experience students get in VRC is no less fulfilling.

If fact with VRC not limiting design and construction time I have found that young designers get more out of VRC than FRC.

9

First, given that FIRST competition is not life-or-death, Darwinian survival of the fittest competition, I would rather compete poorly than not at all (lord knows I’ve done enough of the former). Nuff said about that.

3 years ago, we initiated a summer program to explore technology arenas which we believed would benefit the team. Each summer, we select one or two areas to explore. We do half-scale designs and build using VEX parts. We test them. We develop software. We make observations. We do the math. In the end, we take the concept to a hypothetical FRC-scale design in Inventor®.

So, first summer we worked on drivetrains (6wd & “twitch”). Second summer, we worked on drivetrains (Pivot Drive). In both cases we were able to exploit the knowledge developed in the following year. Working on drivetrain is easy. There are a lot of options. Executing the more challenging options during build season alone is very difficult. You know that the robot will need to move and a particularly effective drivetrain can provide a significant competitive advantage.