Method for controlling an actuator

A method of controlling a pneumatic actuator for actuation of a pneumatically actuated device, the actuator comprising a piston and a pneumatic cylinder, the piston being arranged to move axially in the pneumatic cylinder, the piston moving as a function of a pressure in a pressure chamber of the pneumatic cylinder, the method comprising the steps of:

• determining, via a path sensor, a present position and movement of the piston within the pneumatic cylinder to a desired position;
• determining at least one pilot control component comprising an amount of force required to move the piston within the pneumatic cylinder from the present position to the desired position, with the at least one pilot control component being determined as a function of at least one of a first sliding friction force and a first static friction force of the piston moving within the pneumatic actuator cylinder from the present position to the desired position;
• and
• adjusting the pressure in the pressure chamber, as a function of the at least one pilot control component, via a control unit which controls at least one of a valve, a pressure regulating means, and a pressure generating device;
• wherein at least one of the first sliding friction force and the first static friction force are position dependent forces that need to be overcome by the pressure in the pressure chamber for moving the piston in the pneumatic cylinder, and the first sliding friction force and the first static friction force are dependent on a movement direction of the piston and the present position of the piston within the pneumatic cylinder.