System and related methods for sensing forces on a movable barrier

摘要

An operator system and related methods ( 10 ) for sensing forces on a movable barrier ( 12 ) includes a motor ( 52 ), a trolley ( 30 ), and a trolley arm ( 34 ) having a first end slidably supported by the trolley ( 38 ) and a second end coupled to the movable barrier. The motor moves the trolley arm which in turn moves the movable barrier. A force detection mechanism ( 68 ) is coupled to the motor to determine a first component force value applied by the motor. A controller ( 54 ) receives the first component force value and determines a detected force value by scaling the first component force value with a second component force value derived from an angular position of the trolley arm's first end with respect to the trolley. The angular position of the trolley arm may be fixed or variable. An angle potentiometer ( 72 ) is coupled to the trolley arm to generate an angle signal for use as the second component force value when the trolley arm's angular position is allowed to vary.