Abstract: An apparatus for use in an automatic door system. Means are provided which compares the current position of the running door with a deceleration point to generate a low speed command upon their coincidence. A speed control responds to decelerate the door to a selected low speed. A measuring device measures a variable run-length of the door which is subject to variations in the mechanical condition of the door. In one embodiment, the device measures a low speed run-length over which the door has moved at a low speed. A comparator compares the measured low speed run-length with a preselected optimal low speed run-length to obtain error or departure from the optimal value. A correction logic produces an updated deceleration point by removing the error from the former deceleration point.

Abstract: Apparatus for automatically controlling the operation of a reciprocable door between its closed and opened positions. A position sensing means is provided for sensing the position of the door during its opening and closing strokes to decelerate the speed of the door at a final portion of the door stroke, thereby preventing the door from striking an outer door frame.

Abstract: A method of driving a door of an automatic door assembly by a linear motor mounted within the automatic door assembly. The method comprises the steps of driving the door by at least a normal propulsion force of the linear motor, driving the door by a propulsion force which may range from zero to nearly the normal propulsion force, and then driving the door by the normal force again thereby reducing the speed of travel of the door during its opening and closing intervals.

Abstract: A method of driving a door of an automatic door assembly by a linear motor mounted within the automatic door assembly. The method comprises the steps of driving the door by a normal propulsion force of the linear motor and then driving the door by an added propulsion force which is greater than the normal propulsion force, at least during a final portion of the stroke of the door thereby overcoming the reaction force of cushioning devices provided near the ends of the door stroke.