Mar.26 Mechanical arm and claws

Looks like the first lab exercise is changing from the line follower to a mechanical arm because another institute deals with moving robots and automation. At the moment it seems the need for  hysteresis controller is gone.


Main Task:  Using IEC61499 and the Lego robot claw arm grab an object and drop into boxes of various heights. 
Use step-wise refinement:  
1. Motor movements (up/ down; open/close; right/left)
2. Safety shut-off: Stop with touch indicates down
3. Do something: 
    3a. Grab ball
    3b. Go up with ball
    3c. Move to right or left with ball
    3d. Release ball in a box
4.  Do all steps in 3 together:
    4a. using switches
    4b. Automatically


Advanced task: (from  NXTprograms Robot Arm)  Exchange two balls.


The NXTprograms Robot Arm is used as the base design.
It used 3 motors:

• circling (left/right)
• up/down
• open/close of a claw

A touch sensor is included as a switch.


Added for the lab:

• LED for indicator  
• Touch sensor on arm attached to the claw motor to know when the robot arm is down

claw with touch sensor for down

3 claws are being tested

1. NXTprograms Robot Arm  4 prong claw with 2 prongs fixed
• simple 
• fixed in one position on one side
2. 3 Prong Claw (not sure original author)
• NXT Claw Car with Game Controller - NXT Programs steps 25-32

• LEGO MINDSTORMS NXT Build Instructions 3-prong Claw

3. 4 Prong Claw with full motion  (land version of our team's waterbotics claw in Jan.)
• must be fixed  on the side, so doesn't move 
• uses gear train