Talk:DEWBOT VII Drive Train
From DEW Robotics
This is a space to capture Drive-Train observation, problems and ideas. Please feel free to post here.
Finger Lakes
- Pivot drive repeatedly jammed (drive jam, not steering). Problem appears to originate with the wheel axle collar, some of which cannot be tightened securely. When the collar moves, the wheel shifts on the axle. The wheel shift causes the chain to jam on the 9T sprocket, which is not chamfered. Sometimes the jam is momentary. Sometimes not. One such jam led us to change a pivot on Thursday, another unfixed one effectively disabled us in the semifinals. A few more likely froze us at different times in qualifications, once getting us stuck in an opponent's lane causing a penalty. Since the jam stalls a CIM motor, these jams run down our batteries extremely quickly.
- The semifinal collar may well have been suffering from the same issue duex's LF pivot was: it slipped off the shim entirely and thus was tight but still larger than the shaft OD. (Seems more likely than stripping, as I think you would have noticed that when you tightened it.) We should check that before sizing the spacer in Philly, because with a high enough axial load it'll probably push back over the shim. - Siri
- Post-FLR, problem resolved by fitting removable spacers into the gap between the collar and the jam nut.
Post-FLR
- We killed two steering motors (Banebots RS-540s), one each on Tuesday 15-March and Thursday 17-March. In each case, the physically arrested: on 3/15 by a broken encoder standoff; on 3/17 by a loose #10-32 x 2.5" spacer bolt, which jammed the pivot rotation. Lesson: stopping the steering toasts an RS-540. Repairs made. Replacement motors & pinion gears ordered.
- We killed our first Vishay sensor on Saturday, 19-March. The 10-32 stud connecting the Banebots steering shaft from the Vishay coupling unscrewed in service. It appears that this was not loctited. This drove out the Vishay, bending the shaft. Replacements ordered. As of Sunday, 20-March, the arm encoder has been moved to replace it (duex's RF), and the arm motor is unplugged.
