Pneumatic systems are mechanical systems that use compressed gasses. They are similar to hydraulic systems, which are mechanical systems that use liquids in the transfer of forces. Pneumatic systems are almost everywhere in the modern world. Dentists use pneumatics to operate drills, carpenters use pneumatics to power air hammers, truckers use pneumatic brakes and NASA uses pneumatics to control the operation of satellite launch vehicles.
Pneumatics is basically a method to turn electricity into mechanical motion using compressed gasses instead of motors or electromagnets. For many applications, this is much more efficient and practical. Systems typically include an air compressor, which stores compressed air in a cylinder and release it under electric control. The compressed gas is almost always ordinary air because it is free and non- toxic. Often the air is slightly modified by taking out some of the water vapor and adding a small amount of atomized oil to make the gas more machine friendly.