Control apparatus for an automatic door with a minimum error in a detected door position

In a door controlling system including a door, means for driving said door to run between ends of its stroke having final movable transmission means directly coupled to said door, speed control means for controlling said driving means in such a manner that said door will be initially accelerated from one end of said stroke, then run at a high speed, then be decelerated, then run at a low speed, and finally stop at the other end of said stroke, thus completing one stroke operation of said door, the improvement comprising:

• sensing means disposed relative to said final movable transmission means for generating pulses having a pulse repetition rate in proportion to the velocity of the movement of said final transmission means;
• door position detecting means for counting said pulses from said sensing means to obtain the current position of said door;
• means for providing a deceleration point associated with said one stroke operation of said door;
• and
• means electrically coupled with said speed control means for comparing said current position of said door with said deceleration point to generate a low speed command upon the coincidence of said current position with said deceleration point so that said speed control means will decelerate said door toward said low speed in response to the generation of said low speed command.

A door controlling system, comprising:

• a door having a given stroke;
• driving means for driving said door to run between ends of its stroke, and including final movable transmission means directly coupled to said door;
• speed control means for controlling said driving means in such a manner that said door will be initially accelerated from one end of said stroke, then run at a high speed, then be decelerated, then run at a low speed, and finally stop at the other end of said stroke, thus completing one stroke operation of said door;
• sensing means disposed relative to said final movable transmission means for generating pulses having a pulse repetition rate in proportion to a velocity of movement of said final transmission means;
• door position detecting means for counting said pulses from said sensing means to obtain a current position of said door;
• means for providing a deceleration point associated with said one stroke operation of said door;
• and
• means electrically coupled with said speed control means for comparing said current position of said door with said deceleration point to generate a low speed command upon a coincidence of said current position with said deceleration point so that said speed control means will decelerate said door toward said low speed in response to generation of said low speed command.

An apparatus for controlling operation of an automatic door, comprising:

• an electric motor;
• movable driving means mechanically coupled with said motor and coupled to said door;
• sensing means positioned relative to said movable driving means for generating pulses having a pulse repetition rate in proportion to a speed of said movable driving means;
• door position detecting means coupled with said sensing means for counting said pulses to obtain a current position of the door;
• and
• control means responsive to the obtained current door position for controlling operation of said motor.