Patent ID: 7372224
Filing Date: 2008-05-13
Classification: H02H,H02P

Abstract:
1. A barrier operator comprising: a direct current (dc) motor; a first measuring apparatus for measuring a current used by the direct current (dc) motor to move a barrier; a second measuring apparatus for measuring a generated voltage of the dc motor, the dc motor being driven by a string of voltage pulses, the string of pulses having a plurality of on intervals and off intervals and the second measuring apparatus measuring the voltage during at least one of the string of the off intervals when the motor is operating at a range of speeds during a cycle of opening and closing a barrier; a controller coupled to the first measuring apparatus and the second measuring apparatus, the controller programmed to calculate a torque of the dc motor by using the current and to determine when an obstruction exists in the path of the barrier based upon the calculated torque, the controller being programmed to determine a speed of the motor from the generated voltage, and to determine a position of the barrier using the speed; and wherein the controller is programmed to responsively adjust the speed of the motor based upon the position of the barrier anywhere over a continuous speed range and anywhere along a path of the barrier based upon the determined position of the barrier.