FLL and the EV3

Lego Education has started shipping the next Evolution of Lego Mindstorms Brick, the EV3. I’m excited to say that I got mine and I’m spending way to much time playing with it. Well, I also wanted to learn more about it so I started digging into various on-line resources. Some are obvious, some may not be.

Lego Education: Lego Education information (Obviously)
Links to information on the EV3: The Next Step
EV3 Programming Videos (Thanks to 4476, the Waffles: EV3 Programming Video

There’s many more sites that have information on the EV3. I’m going to try not to repeat much of the information in the sites, but I do want to give some of my opinions. Below is my EV3 in it’s default configuration as built out of the box.

EV3_default_resized

 

One of the things I really like the EV3 sensors is that it comes with a gyro sensor. That means it can be used with FIRST Lego League (FLL). For those who don’t know, a gyro sensor can be used to determine how many degrees the robot has turned. That means teams don’t have to guess at turns, they can make their turns exact. Robots can now use degrees for driving distance and then degrees to do an exact turn.

It’s advertised that the old Lego sensor’s will work with the EV3. For the most part this is true. Most of the sensor’s I tried (i.e. touch, color, light, etc sensors) However, my distance sensor from my NXT kit didn’t seem to work as well, the distances were slow to change and would get stuck at 22cm. It could be a bad sensor on my part.

Another feature that was in NXT-G as well as EV3-G programming languages is that you can make an exact copy of a block by clicking on the block, hold the <ctrl> key left click on the block and drag. This will make a copy of the block. Quick and easy.

So far, this is what I’ve found. I’m going to be playing with it and with the 2013 field to see how it all works.

Good Luck, Have Fun, and Work Hard

 

FLL Stratagy – some easy targets

Easier missions are the missions that are closest to the base and with the larger targets. Attachments can make the hard targets easy as well as well as using sensors and lines or the wall to make missions close. For instance bowling, the robot can move all the way down the field, hit the wall with a touch sensor and then you know you’re near the bowling lanes.

The large video screen is the closest to base should be a fairly easy task to do. The easiest way to manipulate this is to push down the handle but to do that the robot needs to move out of the base, turn, and use some type of manipulator that pushes down the arm as it moves over it. Some other ways to manipulate the arm are:

  • reach over the screen and push the arm down
  • push up the flag
  • Or probably the easiest, go around the screen and pull the handle down.

Another fairly easy target is the blue quilts. All the robot needs to do is to push the two blue quilt squares from the base to the other two blue squares. It’s not quite a straight shot so the robot would have to push the squares out, turn slightly and push the squares to touch the black scoring area’s next to the other blue squares. Something will need to keep the squares from sliding to the side when a turn is made.

The “chair back to the base” portion of the wood working mission. should be somewhat easy. The goal is to move out grab the chair and bring it back to base. The trick is to have an attachment to grab the chair. One way may be to have a latch go across the where it would pull the chair back. Another way would be to have a hook of some type loop the chair and pull it back.

These are just a few of the strategies to get you started. You still need to do the programming and build the attachments.

Good Luck. If you have any questions, please e-mail me.

FLL – The Chassis

The chassis is the base of the Robot on which all missions are completed. The motor, the wheels, the brick are typically all built onto the chassis to become the chassis of the FLL robot. Everything here is my opinion and should not limit any design. Kids can come up with designs that over come any limitations.

There are lots of different chassis, some good and some not good for FLL. There are a lot of things to consider. Some things to consider are:

  • Number of drive motors
  • Tracks or wheels
  • How, where, number, and size of wheels for the robot
  • Caster vs. 3rd wheel, vs. slider
  • Chassis size
  • How to attach attachments
  • Make the robot go straight

Number of Drive Motors

Typically there are 2 drive motors so 2 wheels driving the robot. Another design could be one drive motor and one motor to steer the robot sort of like a car. A motor driving two wheels and a motor to turn the robot left or right. With 2 drive motors, the 3rd motor is available for attachments.

Wheels or Tracks

When thinking tracks or wheels, the missions need to be considered. Tracks typically make for a slower robot and the turn can be inconsistent because the point on the tracks that make the turn may be inconsistent. However, for traction and going over small obstacles, tracks are great.

For wheels, they are move consistent on turning, wheels are typically faster, smoother, and more accurate. Wheels can have trouble getting over obstacles.

How, Where, and Size of wheels for the Robot.

The placement of the wheels are restricted by the placement and size of the motors. With ingenuity, there isn’t a lot of restriction because of the placement of motors.

The number of wheres is a big choice. With 2 wheels your robot is a teeter-toter. If you go to 3 wheel you now have a more stable robot but could have problems with turning. 4 wheels are stable but with only 2 wheels attached to motors the wheels not driven may be drug as the robot turns, and wheels to drag to well. With 4 wheels being driven by the motors (2 wheels for each motor), there still may be issues driving.

5 wheels…hmmm. I’ve never seen 5 wheel robot, but if someone has one, send me a picture. Six wheels may be OK, however there are problems turning and dragging wheels.

The size of wheels are important, too. Large wheels make the robot go faster. However, they also make the robot larch to start and stop. Going small distances may not be very easy. It may also raise the center of gravity where it may turn over easier. The smaller wheels are slower, but more powerful for going up ramps.

Caster vs. 3rd wheel, vs. slider

If you’re going with 3 or 4 wheels, the back wheel can be a wheel, a caster or a slider. A slider is simply a Lego piece that slides around the mat. It doesn’t roll so it can slow down the robot slightly and may not be able to be drug over obstacles. Below is a picture of a robot with 2 rear sliders.

Robot slidersA rear caster using a Lego ball as a 3rd wheel. It can roll any direction for turns but it is harder to build. Below is a picture of a Lego caster.

Caster RobotA 3rd caster wheel works well for going forward. However, if the robot backs up the caster wheel may push the robot to move at odd angles. And then when it moves forward again the wheel may start the robot out at an odd angle.

Caster wheel

Chassis Size

First, the chassis needs fit in the base. Also, it needs to be the right size to move around the mat, between the missions and other obstacles. It also need to be low enough that it doesn’t fall over while moving around the mat.

Chassis Attachment Attaching

The front of the robot needs a place to attach attachments. it needs to beams with holes in in places that allow other beams to be attached. It needs to allow for quick connect and quick disconnect. Below is my chassis attachment area. It’s probably not the best but it works for me. And that’s the key, it works for you.

How to make the robot go straight.

The best way to do this is by building the chassis correctly. Here is a video that helps with how to get your robot to go straight. The wheels need to be straight up and down. If they bent out at all, it could cause the robot to go crooked. Also, one thing to give the wheels more support is to put a frame around the outside of the wheels that supports them. This is shown below on my robot. The motor is on the inside of the wheels and a frame goes around the outside. The axle that goes between the frame and motor for support.

Also, just finding wheels that are the same size is really important. Sometimes, the wheels are slightly different and that can make them turn to the side.  If you choose 2 wheels, put an axle through the center of the wheels and roll them it shows if they’re the same. If the wheels roll to one side, then they are slightly different.

 

FLL – The Project

I want to start out by saying the project portion of FLL is my weakness, I haven’t worked on projects like this since my kids were in middle school, 8 years ago.

Any responses/ideas/thoughts that could help others with the project would be appreciated. Since I am a beginner at this and I’m trying to help everyone, I appreciate others help and others ideas.

Everyone needs to remember that the project is 25% of your overall score. So I want to learn, even though the coaches are dealing with the project portion. I started by reading the Rubrics and the Project FAQs. Then I went to a local FLL workshop put on by a Longtime North Texas FLL Coach, Sherry Oliver at TCU. It was really great and I learn a lot.

The project presentation takes place in front of judges. The kids have 5 minutes to present from the time they enter the door. The judges then have 5 minutes to question the team. For the team, that’s it. The judges will continue to deliberate for 5 minutes before the next team.

One suggestion that came up was a Project notebook, as well as a Robot Build note book, and a Team Notebook (for core values and team work issues).

So what should go in the Project note book.The simple answer is all information that was found while researching the project.

  • Keep the brain storming ideas for the project.
  • Information on the problem.
  • Any information found while researching the project
  • Information on the solution
  • Information on
  • Pictures of the kids meeting with experts
  • Pictures of any field trips
  • Picture of your senior partner
  • Current Technologies that could could be used, made smaller/better/faster to  solve the problem

The project notebook would be given to the project judges to review. But make sure you get it back at the end of the day.

The project needs to be a problem that could possibly lead to a solution. Basically, you need to follow the process of:

  • Find a problem
  • Come up with technologies that could solve the problem
  • Think about technologies that would can be made smaller, better, or faster to solve the problem
  • Think of things that can be done possibly in the next 5 to 50 years.

If the problem has a solution that can be done today, then have plans that could lead to the solution should be presented. Letters to people/groups/businesses asking for change. Plans for items to be created to solve the problem or plans to work with an expert to solve the problem.

Thanks to Sherry Oliver and everyone else who is and will be helping me on my quest for learning about the FLL project.

 

 

FLL – attachments

I’m doing this a bit out of order, the chassis is the first thing to build. After that comes the attachments. I’ll write later about the chassis later.

Attachments are extra Lego pieces attached to the robot to accomplish a task. Sometimes motors are used for the attachment, sometimes it’s just the Lego parts to make an attachment. Some attachments use rubber bands or string to accomplish a task.

I’m going to talk about some of the simpler attachments that are not very specialized. It’s up to the kids to take the idea’s, modify them, and make them useful for this years missions.

First is a simple horizontal pushing rod. This can be made to stick out to the side of the robot to put things as it passes them.

It can push the arm down on the video calls, turn the cardiovascular exercise wheel,push over the similarity mission, push the lever of the shared ball game as it passes by the mission item.

The next simple attachment is the plow. This is for pushing cargo to it’s destination. In the picture below the plow has sides on the plow to keep cargo corralled during movement. This would be a good attachment to push the blue quilt pieces into place or after the chair has been retrieved and fixed, it would be pushed under the table.

Another attachment is a simple latch. The latch is used to drag something back to base. To use the latch the robot moves over an object, the latch clicks into position and as the robot backs up, the object is dragged back. The key to the latch is the Lego hinge is a gray connection piece, not black. the gray is designed to allow Lego movement.

A slightly more sophisticated latch can use a cage that drops when the latch is hit. It can also use a rubber band to make a cage to drop and hold. I’ll write more later about it and give a picture.

FLL Stratagy

There are many levels of strategy for doing the various FLL missions. I’m only going to talk about some of the basic strategy to start the kids thinking about how to do the missions.

The best strategy is to read the game manual. Read it closely, brainstorm with others, and think about what the description says with not preconceived ideas. For example, the Transitions mission says “Robot gets onto the center platform…”, it doesn’t say how to get on, you can get on from either end…or possibly from the side by tilting the center platform to the side and moving onto the platform.

Take a look at the game mat. In general, look at the missions to see how “easy” they are. Typically, a mission is considered easy if they are close to base or the missions with larger target to hit.

Missions such as the video call near the base, the wood working (retrieving the broken chair), retrieving the service dog, and possibly the blue quilts are fairly easy.

Missions such as the cardiovascular exercise, similarity recognition and cooperation, ball game, the lower hoop on flexibility, the orange quilt, the gardening, the strength exercise, and transitions are medium hard.They are a bit further to get to or have a small target to hit. When something is further the robot accuracy isn’t as good. Same with small targets. The transitions has obstacles to complete the mission which makes it medium hard.

The rest of the missions…the medicine, bowling, strength exercise, stove, the far video call, and the upper flexibility hoop are all hard, they are far and small to activate.

The Cardiovascular Exercise is the “impossible” mission. This is simply because there’s not really enough time to get it done along with all the other missions. It has to be visited multiple times (6 times with no touch penalties) while having to do all the other missions.

Also, there are lines on the game mat. This lines can help with movement, they can be followed to get to a destination, used to straighten the robot, or tell where you are by moving until you hit a line . Line following or robot movement until you hit a line is a strategy. The lines are a bit different this year. There are green lines, dashed lines, lines going from light to dark. We’ll have to get into the missions to tell how this will affect the game.

We’ll talk specific mission strategy next time.

Again, if you have any question, e-mail me at frc704mentor@qweztech.com.

FLL portable walls

Note: August 28 is Robot Game release…WooHoo!!

Last year I worked with a team at a school with almost no storage space near the robot room. There was little enough room for the boxes of Robot Lego’s, much less a practice table, even a portable one. We practiced on the floor on missions that were in the center of the mat with no need for walls.

This year, I don’t want any teams to fall into the same predicament. I had heard rumors of how to build portable walls but hadn’t found the plans. So I came up with the follow plans for portable walls that fit in a small storage area and are cheap to build.

It can be used for practice on the floor, or they can be taken to qualifiers and used for your own practice area.

Here’s the link – http://www.qweztech.com/OtherRobotics/FLL Floor Practice Table.pdf

It’s at my FIRST mentoring website – http://www.qweztech.com

It costs less than $25, stores in an area about 48″ X 4″ X 12″, and weighs less than 25 lbs.

I hope this can help some people. Good Luck