Position controlled drive mechanism

A control method for the position of a drive mechanism comprising, in no particular order:

• providing an electric motor provided with a rotatable shaft;
• providing a sensor for generating a displacement signal indicative of a displacement of a movable stop operably connected to the rotatable shaft;
• providing a controller so connected to the electric motor as to control the rotation of the rotatable shaft therewith;
• transferring the displacement signal to the controller;
• configuring the controller to calculate a position of the movable stop based on the displacement signal and to alternatively perform at least two of the following modes of operation:
• a) controlling the electric motor to rotate the rotatable shaft to reach a selected position of the movable stop;
• b) controlling supply of voltage or of current to the electric motor to maintain a current position of the movable stop, wherein the supply of voltage or current is cut if a large force applied to rotate the shaft prevents maintaining the current position;
• c) controlling the electric motor to rotate the rotatable shaft in a selected direction until an external object hinders the rotation of the rotatable shaft;
• and
• d) controlling the electric motor so as to assist an externally initiated rotation movement of the rotatable shaft detected by the sensor.