A position controlled drive mechanism and a control method for positioning a drive mechanism are introduced. A sensor generates a displacement signal indicative of a displacement of a movable stop driven by an electric motor. A controller controls rotation of the electric motor. The controller also calculates a position of the movable stop based on the displacement signal. The controller includes at least two modes of operation in which the controller controls the electric motor to rotate its shaft to reach a selected position of the movable stop; controls a voltage or current supplied to the electric motor to maintain a current position of the movable stop; controls the electric motor to rotate the rotatable shaft in a selected direction until an external object hinders the rotation of the rotatable shaft; and controls the electric motor to assist an externally initiated rotation movement detected by the sensor.