The air cylinder uses the same compressed
air supply system that the bubble lifter does. Once the air system was in place it was very economical to extend the system
to include operating the claws.
The on board pneumatic system is here: The pneumatic system
These particular air cylinders are single
acting, spring return. This means that when air is applied the rod extends and when air pressure is removed and the air is
allowed to escape the rod retracts due to the spring force alone. This also means that the claws normal position will be “Open”.
With a different air cylinder this could be changed, a “spring extend” cylinder would normally have the claws
closed but would also be limited to the spring force to hold the claws closed. Other possibilities would require air cylinders
that are double acting but this would also require different solenoid valves
A great thing about using pneumatics
is that within reason the claw will grip based on force, not position. No feedback or force measurement is required. Say the
claw is gripping an irregular object and said object shifts a little. The claw will just maintain its grip on the object and
hopefully not drop it. At the moment there is a single pressure regulator that maintains the air pressure in the claw system.
It would also be simple to have 2 regulators, one for low pressure and one for high pressure. Each regulator would also have
to have its own solenoid valve. This could be set up so that normally only low pressure air was used, just enough pressure
to make the claw move. When necessary the high pressure could be used for times when “Crush, Kill, Destroy” forces
are needed...
