Sept.9 Application Time - Robot Arm

Chose 3 robots, which use few parts, to build and use with test applications,
First Lego arm to test motor FB in applications and for something new and 
because the other 2, (a CarBot, NXTway) use motors.


New motor FB since easiest to change directions in an application via a boolean:

Test 1: Test each motor going back and forth.  Same test was used for all 3 motors.
First simple alternating test with Flip-Flop

Test 2:  Used 2 Touch sensors - 1 turned motor on and 1 reversed the motor direction (both had to be pressed at same time)

Test 3:  Should allow testing of all 3 motors in 1 test.


Lego Arm test reflections / results:
1. Discovered easiest to change motor direction with BOOL input variable, 
so new Motor FB. 
Open: How to switch between on/0/off = tri-state
This is a general problem. Ref: http://www.societyofrobots.com/member_tutorials/node/161

2. Then a good test for changing directions  is using a flip-flop.
Created a F_FLIP FB that is a flip-flop built with 2 delays and 1 SR. 

This design was chosen because it uses 2 rather than 3 types, since each 

downloaded FB type takes more or the limited space.


Using F_FLIP FB there are timing issues. Usually goes back and forth, but sometimes misses one and goes twice in the same direction. Solution is probably to use E_CYCLE even if it an extra FB Type has to be downloaded.


3. Physical results:

• Open/Close - 
• hit on bottom of the other claw
• needs short times and little power
• Up/Down 
• Down is noticably faster than Up due heavy motor on the end of the arm
• Flop-flop with 2 equal delay times allows it to wander down fast.
• Can hit on motor if goes to far over
• Left / Right - works as expected