There was an error in my truth table (Extended/Retracted values
were swapped). This was likely why the buttons weren't corresponding
to the correct tusk positions when tested today, 2/23/14, on the practice
chassis.
Note that there is a 'bug' in that it is impossible to move the tusks
from the "Retracted" position to the "Middle" position. This was observed
on the robot today. There wasn't enough time to debug this before the
meeting ended tonight, but the problem is quite evident upon further
review.
When in the Retracted position, C is fully pressurized. Subsequent
commands to the Middle position will not cause motion. Review of the
Middle valve positions shows A will shift from being vented to being
pressurized, and more importantly: C will continue to remain pressurized.
C being pressurized will prevent motion of the actuator that A is
attempting to extend. Hence the observed behavior.
A possible solition is to, upon reciept of the order to the Middle
position, vent C, and pressurize A. Then a short time later, pressurize
C.
Note, pressurizing C when attempting to achieve the "Middle" position is
necessary to prevent the secon stage actuator from beign easily driven
to the extend position when the B and C ports are vented. If B and C
were vented, it is likely that the tusks would shift to the extend
position when the catapult is fired.
There was an error in my truth table (Extended/Retracted values were swapped). This was likely why the buttons weren't corresponding to the correct tusk positions when tested today, 2/23/14, on the practice chassis.
Note that there is a 'bug' in that it is impossible to move the tusks from the "Retracted" position to the "Middle" position. This was observed on the robot today. There wasn't enough time to debug this before the meeting ended tonight, but the problem is quite evident upon further review.
When in the Retracted position, C is fully pressurized. Subsequent commands to the Middle position will not cause motion. Review of the Middle valve positions shows A will shift from being vented to being pressurized, and more importantly: C will continue to remain pressurized. C being pressurized will prevent motion of the actuator that A is attempting to extend. Hence the observed behavior.
A possible solition is to, upon reciept of the order to the Middle position, vent C, and pressurize A. Then a short time later, pressurize C.
Note, pressurizing C when attempting to achieve the "Middle" position is necessary to prevent the secon stage actuator from beign easily driven to the extend position when the B and C ports are vented. If B and C were vented, it is likely that the tusks would shift to the extend position when the catapult is fired.