Thursday, August 14, 2014

FLL - World Class: To Tire or To Track, That is the Qestion...


The FIRST LEGO League 2014-2015 World Class Learning Unleashed challenge is upon us and some teams will be using the Mindstorms EV3 kit. With the Mindstorms EV3 Educational kit comes Tracks and you can also purchase from LEGO Education Rubber Studs that can be inserted into the tracks. If you have Retail Mindstorms EV3 kit you can purchase both Tracks and the Rubber Studs at  legoeducation.com . Now, the question may arise, what is best to use on this year’s smooth field mat – Tires, Tracks, or Tracks with Rubber Studs????

Well, with the help of my student assistant Brandon, we ran a number of tests on the field mat, using an EV3 robot with 2.125 Balloon Tires and another robot with Tracks & Tracks with Track Rubber Studs. The tests and his observations are as follows:

Balloon Tires (2.125) 
The first three tests were with a robot with 2.125 balloon tires (we used the Pivot Ball as the third wheel). The robot was programmed to move forward 4 rotations with the Move Steering block and with powers at 50, 75, and 100; the performance was excellent. The moving backwards with Move Steering and the results are powers at 50 and 75 the tires are excellent. however, at 100 power it was very good; there seem to be a little friction. We tested turning forward and with powers 50, 75, and 100; turning was excellent. The second three tests with the 2.125 balloon tires using the Move Tank block, the results were exactly the same.

Tracks 
In the first three tests using tracks; moving forward with Move Steering at a power of 50; the tracks the performance of the robot was very good on this power. Then we ran the test again with power, 75; the result was also very good. The last power was 100 and the result was poor, indicating slight slippage and reduce speed.  The moving backward with Move Steering results at 50 and 75 power were very good, but again 100 power was poor. Turning with the Move Steering block, with 50, 75, 100 power gave a fair performance. The second three tests using the tracks and programming with the Move Tank block and turning produced the same results as with the Move Steering block with tracks.

Tracks with Rubber Studs 
Next we added Rubber Studs to the Tracks. The first three tests using Tracks with Rubber Studs, moving forward with the Move Steering block, at the power of 50; although the traction is good, the performance was fair in relation to the speed of the robot. We then ran the test again with next power of 75; the result was also fair. The last power was 100 and the result was fair too. Moving backwards with Move Steering, the results at speeds of 50, 75, and 100 was fair. Turning using the Move Steering block, at 50, 75, and 100 were also fair. The  second series of tests with Tracks  and Rubber Studs; moving forward, backwards, and turning revealed the same results as with the Move Steering block. Note: traction was “bumpy,” but very good using Tracks with Rubber Studs, but very slow even at 100 power.

Conclusions:
With this year’s World Class: Learning Unleashed field mat, it seems that wheels with tire treads work the best as far as traction and speed is concerned. It is recommended that teams try out different tire types and sizes. However, teams should not dismiss the use of Tracks because they do give a pretty good performance at 75 or less power. As for the Tracks withe Rubber Studs attached (experiment with different configurations of Rubber Studs attached to the Tracks - less, different patterns, etc.); the traction is good, although  bumpy and  bit slow, but if you have to go over an obstacle its excellent - “Look out! Tank coming through!”


Move Steering Moving Forward

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