Archive for the 'prototyping' Category

16
Jan
12

Prototyping and Trying it out

I hope everyone is doing well this second week of Robot build season. Last week and possibly early this week everyone should have a chassis planned, a way to get up and down the field, and maybe some way to get the balls to a hoop.

But first, a lot of people are having trouble setting up the cRio and LabVIEW software. I’d like to suggest to RTM (Read The Manual). Most of the information is in the document at this link (https://decibel.ni.com/content/docs/DOC-20204)

On with prototyping: You don’t necessarily need to do everything in the game. If you’re a rookie team you might think about doing one thing very well. One thing that can be helpful is getting the balls from one end of the field to the other. Or you might play defense well, keep the balls from moving or have some type of shield that moves up to 84 inches to block shots.

No matter what, by now you should understand the game and how you plan on playing it.

When you know how you want to play the game and are designing your robot to play you should brainstorm on how to get your robot to do it. Prototyping is a way of trying out thing quickly before going to the time and expense of building it on your robot.

To prototype, decide what you are trying to test to see if it would work, quickly build something out of wood or plastic that is approximately what you want and try it. Sometimes parts are C-Clamped together or tied with rope.

One example is a couple of years ago on Breakaway, we were prototyping a ball kicker. First we rigged up some pneumatics on the kitbot, held a pneumatic cylinder by hand and punched the ball. It didn’t work well. We then screwed a frame down to the floor (Our Robot room is an old trailer), took some surgical tubing, rigged up a wooden kicker on a long meddle screw. We would pull the kicker by hand and see how well it would work.  We the switched the surgical tubing to pneumatics and tried it again. We liked the pneumatics the best. It took about 5 hours to try everything, we didn’t waste time building a full robot part to see if something worked or not, and we had a pretty good robot that could score from two-thirds of the field and move the ball the full distance.

Good luck to all

08
Jan
12

Sample Schedule for FIRST 3 weeks

Hey every one, due to work, I’ve been out of pocket for a while…But it’s Robot Season and time to really get down to the most fun work you’ll ever have.

Scroll to the bottom for Woodie Flowers presentatono from the kickoff.

To all the Rookie teams: One problem I’ve seen in the past is, teams that have never been through this get over whelmed easily. Between the robot build, reading the manual, and organizing the team with kids who have never been through this before either, time gets away from people. Teams will put off building the robot until the last minute. This is a huge problem because a robot is not built in a week. Here is a sample schedule for when things need to get done.

Please try not to stress out too much and remember there are people out there who can help. Look at FIRST event at the teams that will be at the event you will be attending and contact one of the veteran teams. They’ll usually help. Or contact your regional director, or contact me and I’ll see what I can do to help. I’m Joe Varnell, Engineer at Lockheed Martin, Technical mentor for Team 704, and my e-mail is frc704mentor@qweztech.com. I don’t want the rookie teams to get stuck. Also, don’t wait until the last week of the build to get help. Ask as early as you can.

Organize your team. There needs to be programmers, electrical people, frame/gear/build people (i.e. gear heads). Unless you have a large team, everyone will probably be doing a little of each. Plus, some kids may want to try it all so they can see what they are most interested in. There should also be a student team leader who knows what’s going on in the various parts. FIRST has information on organizing teams at this link (http://www.usfirst.org/roboticsprograms/frc/mentor-resources-library).

Week 1 – Figure out “What” needs to be done (Requirements) and “How” your robot will drive

Read the manual!!! This is probably the hardest part because there is a lot of other stuff to do and people, especially kids, want to get on with the robot building.

Analyze the game and the rules for the Robot. Figure out your drive train.

Brainstorm on what how you’re going to do things. Remember when brainstorming, no idea is a bad idea. Some ideas that seem to be “out there” may start other people thinking about different ways of doing things. Once you have a bunch of ideas, start narrowing them down to idea’s that can be implemented by you. You can also refine some of the ideas that have already been brought up.

Have the programmers start testing the sensor’s, learning the language, and running the example programs.

Find someone who can help with building using whatever materials are going to be used on the robot. Some teams will use aluminum, some use carbon fiber, possibly fiber glass, and many people used wood (Last year many teams used wood). A mediocre to good machinist can really help a team.

Week 2 – Continue design and prototype

Figure out what type of appendages and apparatuses you need to do the job you want and try some stuff. Issues that should be though about are things such as, this year is a shooting game, do you just want to dump balls in the lower basket? Do you catapult like arm to throw balls? Do you want something like a baseball pitching machine?

Build prototypes to test the designs. Prototyping is just rigging up something that is similar to what you want and seeing if it will work. You might use wood or PVC. Be safe while your prototyping, sometimes the apparatus need to be held together by hand while testing.

Begin building the chassis frame, put on the transmission, and figuring out where everything will go.

Week 3 – Build the drive train and continue to prototype.

Continue on with building the Chassis, putting on the motor’s, wheels and chains.

Finish up prototyping the appendages and apparatus. Once you get something decided for the apparatuses and start building it.

Good luck

PS Here is the link to the youtube video of Woodie Flowers from the 2012 kickoff. I thought it was very good.

09
May
11

Interesting FIRST

The robot’s this year varied widely as they usually do. The professional team’s robot’s looked sleek as ever and ran really well. [note: by professional teams, I just mean the teams with lot’s mentors, some may even be paid mentors for teams, and large budgets. I don’t mean the team was paid.] The robot’s built up from the kits were anywhere just the kit-bots to some pretty well put together bots on the kit-bot base.

Some of the more interesting robots used unconventional materials. I was most fascinated by the one’s that were made from wood. That’s one material that you don’t really expect to find on a robot. The robot for team 3350, the T-Bots, that I didn’t get a picture of had an elevator similar to a forklift, but built out of wood. It seemed to work well and they were picked in the alliance selection in Dallas.

This robot for team 922 had wooden gears. This is an unconventional use of wood that most probably would have never thought of. However, it seemed to work well. This is a great example of the “go with what you know” principle. If someone understands the properties of wood so that this can work and has the tools to make this, then go with what you know.
Here is a robot in which the tower is made of wood. It was built as a bridge like structure and it seemed to work pretty well. I know a lot of kids do the “bridge build” out of popsicle sticks. This is taking that principle and extending it to a stronger structure (than popsicle sticks) and putting it on a robot.

It just show’s that ingenuity and resourcefulness are a key to robot building. PVC was used a lot, however, not that effectively.

One more thing that’s not really robot related but is unuaual none the less was a ringer. I saw a lot of tubes get close but only one that made a ringer. The ringer was made at the Alamo regional and, while it could have received a penalty, since no mini-bot tried to use the tower, it didn’t seem to have been done intentionally, the refs though it was cool and so let it go.

23
Jan
11

FRC build week 2 musings

I hope everyone’s Robot planning is going well. I’m also hoping all the teams have their strategy down and have a plan to fit the Robot to the strategy. Make sure whatever strategy is chosen is done well. If it’s a defensive strategy make sure the Robot is built to push other Robots around or to be the best blocker possible. If you have a scoring robot, make sure you can score quickly and efficiently.

The Kit Of Parts (KOP) came with many sensors, everyone should try to make use of them where they can. The sensors can be used to aid the driver in Robot operation and to help in autonomous mode. Some of the sensors like the wheel encoders can let you know the distance you move. The linear encoder can help the Robot tell the distance an actuator moves. The gyro can help your robot tell which direction it is pointing. All the sensors have examples that are runnable. To get to them, open LabVIEW and in the lower right hand corner of the opening screen are the FRC examples. All examples have diagrams of how to hookup the sensor. Also, all the data sheets are located on the site http://www.usfirst.org/roboticsprograms/frc/content.aspx?id=18530. Make sure you scroll down.

Right now is a very important time in the build, some parts of the Robot are coming together well, some parts are not coming together and are in need of redesigned. Don’t get discouraged, just keep working at it. There are only four weeks left in the build season but it is plenty of time to get things together.

One thing people should think about is Prototyping. Prototyping is to build a quick and dirty model of whatever you are prototyping. One example is the kicker on last year’s robot. We (team 704) built a wooden frame, screwed it down to the floor and then used different things to kick a soccer ball. We made a kicker and tried various pneumatics, surgical tubing, and bungee cords. We made prototypes of different ways to kick a soccer ball. This year you might prototype various ways to put the game pieces on the scoring pegs. Come up with a way to score the game pieces and build something to try out your ideas.

It’s important to get your robot to a point you can test it before the ship date. Getting out there and running it through its paces is a key to success. Last year’s FRC challenge contained humps the robot had to go over. Our robot was ready somewhat early (a week early) and so we did some testing on a practice field.

During testing last year, after a couple of test runs our chains started to fall off and this bent axle is what we discovered. This along with a torn aluminum pan holding the battery. You don’t want to find out about this during the competition.

Good luck to all. Figure out what to do and do it.