Actuator, fluid drive system and method for determining a position of a working piston

The invention relates to an actuator for providing a driving motion, with an actuator housing (31; 68) and a movable in the actuator housing (31; 68) recorded working piston (47; 69) coupled to the actuator housing (31; 68) has a size variable workspace ( 50, 51; limited 70) and wherein the actuator housing (31; 68) a fluid connection (32, 33; formed 67) into the working space (50, 51; opens and 70) of the for providing a fluid flow for moving the is formed; the working piston (69 47). The invention is characterized in that at one end portion of the actuator housing (31; 68) a the actuator housing (31; 68) and the working piston (47; 69) limited measurement space (56, 58; 74) is formed, which upon arrival of the working piston (47 ; 71) is configured for providing a pressure pulse, whereby the measuring chamber (56, 58;; 69) in an end region of the movement path (48 74), a fluid measuring connection (38, 39; is associated with 75) at least temporarily communicating in fluidly connection with the measuring chamber (56, 58; 74).