05/10/12 - Scoring / De-Scoring Prototypes

The team talked about various scoring and de-scoring strategies last night and began prototyping an intake that can both pick up sacks from the floor and de-score or steal sacks from the trough goals. Below are our test videos, all tests were ran with two 269 motors direct driving the wheels:

Test 1: Using a 5 inch wheel for de-scoring from the trough goals.

Result: 5 inch wheel does not grip the sacks well and does not de-score them easily from the trough.

Test 2: Using the 30 tooth sprocket with small tread flaps wrapped around the outside.

Result: Small flaps worked better than the 5 inch wheel and could de-score some sacks. Decided to try larger flaps to see if that worked better.

Test 3: Using the 30 tooth sprocket with some small and some large flaps wrapped around the outside.

Result: De-scored fairly well. We are going to experiment with using a piece of extendable polycarbonate to support underneath the sacks for sack stealing purposes.

05/05/12 - New 6 Wheel West Coast Drive

We have created a 'West Coast' style drive using 5 inch wheels that are cantilevered on the outside of the frame. The drive uses four 393 motors geared for torque. The overall gear ratio uses 60:84 tooth gears for a 1.4 ratio to increase our speed. See the images and video below -

Week one Sack Attack

2012-2013 VEX Sack Attack

Initial tests and notes:

            Current "Vexter Drive":  Mecanum drive 1:1.6 ratio, HS motors set to speed setting.
            Back drive pods are on a joint for movement over obstacles
            Current "Vexter Drive" height:  0.8 in

            Spacing between the front and back pods:  3.3 in

            Sack Specs:
                     Sack not fully flattened: about 2 in
                     Sack on Side:  about 3 in

Tests

                                     Driving over one sack:

                                  Overall success, sack caught on back drive pod.

                                  Trying to push 5 sacks:

                                   Result: Failure 2.5 lbs of sacks cannot be pushed by this drive (yet)

                                 Trying to Drive over 5 sacks:

                        

                                  Overall success, able to move around sacks it was stuck on.

Final Thoughts

Drive has great maneuverability

Able to drive over some sacks 

Able to translate over sacks in the center of drive

Unable to push more than 2 sacks

May need to lower wheels in drive pods to increase clearance

Sacks are definitely a field obstacle