Posts Tagged ‘Robot

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.

20
Dec
10

The FRC 2011 season kickoff is near!! January 8th will begin “Robot Season”. In case anyone doesn’t know, January 8th is when FIRST will unveil the 2011 Robot Competition Game. As most of us know, this is a worldwide event.

For the rookie teams who haven’t experienced the fun and exhaustion of an FRC season, this may be just an announcement of the game and time to get the kit of parts. For those of us veterans of the FRC robot games, it’s the kickoff of Robot Season. Six weeks to design, prototype, build, test, fix, and re-test your robot. The engineers at Lockheed Martin could not get this done, but thousands of high school students do this every year.

My goal is to help the rookie teams to have a fun and successful season. I would also like to see all teams move in autonomous mode, even if they don’t really do anything. Last year I talked with some rookie teams who weren’t sure what needed to be done for the 6 week robot build. They took a long time to plan, a short time to build, and a lot of last minute building/fixes at the event. I’d like to layout a simple time line to follow to allow for a successful season.

I also would like for people to e-mail (frc704mentor@qweztech.com) me during the season if they have questions, need some help, or are stuck. However, one of the best resources for teams is some of the more experienced teams. Most veteran teams are more than willing to help rookie teams. Go to the events list on www.usfirst.org, find the event you’re entered in, and go to see what teams are registered. Find teams with lower team numbers (possibly those under 2000, they’ve been around longest) and see which ones are in your area. Contact them and talk to them, see what they’re doing, if they’ll let you. I know Team 704 in the DFW (Texas) metroplex is willing to let people come out and see our Robot room.

Here’s my suggested time line.
Prior to season start – Learn about sensor’s, learn to program, learn about the mechanical aspects of robots. Build a create that can handle the maximum robot from the earlier seasons. If you don’t use all the weight or size, you can ship extra stuff like tools.

Jan 8th – Go to the kickoff and if they have a quick build session (where you put the robot together with the help of experienced people), go to that.
Jan 9th (Sunday) Each person should think about the game, the scoring aspects, the field elements, and the possible strategies.

Week 1, day 1: BRAINSTORM! Talk about scoring, the field, and possible strategies with the entire team, the mentors. Make sure everyone understands the each aspect.

Week 1, rest of the week: Design the robot. Figure out what you want the robot to look like, what apparatus’ should be on the robot (i.e. kicker, blocker, etc) You shouldn’t decide HOW everything should work, but WHAT should be on the robot. Also think about sensor’s that might help get the job done. Like light sensor for following lines or touch sensor to decide when you touch something.

Week 2: Prototype. For whatever apparatus that will be on the robot, figure out how they’re going to work. You may need pneumatics or electronics, or mechanical actions. Also the programmers should be putting together the program structure. What buttons are going to control what and adding code to deal with sensors and actuators. Also, start putting together the robot, the structure, electronics, pieces that are static. The drive train should be one thing that is being put together.

Week 3 and 4: Keep prototyping and continue building and continue programming. As you are figuring out how the apparatus work, they should be built. Also the programming should be coming along to control them.

Week 5: hopefully, by now, you should have something at least partially put together. So now, Test!! Even if it’s not 100%, test it, see what’s working and what’s not working. Put it under some stress and see what breaks. Imagine what might happen in the game and test it under those conditions or possibly even tougher conditions.

Week 6: fine tune. Do some more testing but the goal of fine tuning. Of course, anything that breaks, fix it and make it stronger. However, you should be fine tuning the connection between the programming, the electronics, and the mechanics. Also, you should take pictures and measurements of your robot.

End of week 6: Either bag and tag or create up and ship your robot. Hold back your cRio and electronics if possible. You can keep programming and trying little things.
This is only a suggested time line. Every robot is different, every team is different, and every game is different.

Remember, your design will change over the 6 weeks, your ideas will change over the 6 weeks, your strategy will change over the 6 weeks so be flexible. Stay focused on the game and the robot for 6 weeks; then relax until the event. And over all, have fun.

07
Nov
10

FRC Touch Sensor

Sensor’s come in handy in Robots. Sensors can be used when the robot is autonomous or when the driver needs some help. In the breakaway game, to help the driver we used the camera to see the ball on the far end of the field and to line up on the target from the middle area. Touch sensors could have been used to sense when the ball was in place and ready to be kicked or distance sensors on each side to help go through the tunnel. And I’ve already talked about encoders to move specific distances.
For next year’s FRC game who knows what sensors can be used. So you need to be ready and understand how sensors work and how you get information from them.
I’ve put in these links before but they are important learning about sensors. National Instruments has some good papers on sensors and their effective use. They have some basic sensor information and their basic paradigm is ”Sense Think Act”.
Digital I/O (DIO) is one of the simplest Sensor inputs. This can be used for touch sensor to tell when you’re against a wall or when something is in place. To get to the Digital IO go to the WPI Robotics Library >> IO >> Digital IO >> DigitalInput pallet.
> IO >> DIO” />
In the DIO example it show’s on the blue digital sidecar that there’s a signal diagram showing three connections, a positive, power, and a signal. For a simple touch sensor, electronics store have some touch sensor switches. Or a simple switch for touch can be built with some stiff wire going through a loop as shown below.

The resistor should be a 2.5 Kohm. The 5Volts will make the value hi when the wire through the loop is not touching. When the ground wire touches the loop it will ground the signal to a 0.

The LabVIEW code from the example is shown below.

The block diagram shows the Digital IO is opened according to the slot the DIO module is in and the DIO line. This example will simply show the value coming in from the digital IO line on the front panel. However, this can be used to sense when something is being touched, a wall, a ball is in the right place, or you’re in contact with a tower. It’s simple but very useful.
More about sensor’s next week.