Hydraulics And Automation have a very deep connection with each other. In automation, hydraulics refers to the use of a liquid to apply a force to a component to produce an effect, usually motion. The definition of hydraulics is operated, moved, or affected by the means of water or other liquid. In hydraulics-based systems, confined, pumped liquid moves pistons, often through hydraulic cylinders, to create mechanical movement. Moving components of mechanical systems that need to lift or push large things frequently use hydraulics. The landing gear in aircraft uses several hydraulic cylinders to position the wheels and cushion the landing.