| 摘要 |
The actuation system of the present invention is based upon sensing relatively small delta errors over relative short strokes as opposed to absolute travel error. An actuation system in accordance with the invention includes an actuator (30, 40, 50, 60, 70, 80, 90 and 100) attached to a structure (C) and an element (20, 21, 22, 23, 24 and 25) to be moved relative to the structure, the actuator causing movement of the element along a path of travel between travel limits (A and B) relative to the structure and having a failure mode when the actuator has moved more than a fixed distance relative to a reference position on the path of travel; a position transducer (34, 44, 54, 65, 74, 84, 94 and 104), coupled to the structure and to the element, for producing an output signal representing a position of the element along the path of travel, the position transducer having a position resolution error along the path of travel greater than the fixed distance; a processor (200), coupled to the output signal, for sampling the output signal periodically a plurality of times during the movement of the element along the path of travel and in response to samples producing a signal indicating if a failure mode has occurred and wherein a sampling rate of the periodic samples is chosen so that a distance that the actuator travels between successive samples times the position resolution error is less than the fixed distance.
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