| 摘要 |
An automatic pitch trim system responds to the output of a torque detector (34) to provide an input signal to a gain normalization circuit (36). A limiter (38) responds to the gain normalization circuit (36) to produce a limited authority trim signal to a summing amplifier (48). Also connected to the normalization circuit (36) is a window generator (42) that responds to the input signal to activate a time delay (46). The time delay (46) generates a control signal to a signal gate (40) having an input connected to the normalization circuit (36). Under the control of the time delay (46), the output of the mormalization circuit (36) is gated through to the summing amplifier (48) to be combined with the output of the limiter (38) into a signal that is applied to a trim servo amplifier (50). The servo amplifier (50) generates an energizing voltage for driving a trim servo motor (44) coupled to trim tabs (52). To detect a malfunction in the automatic trim system, voltages applied to a pitch servo motor (28) and the trim servo motor (44) are input to respective amplifiers (56) and (58) that generate first and second comparison signals to comparison logic (64). When the difference between the first and second comparison signals exceeds a preset limit, the comparison logic (64) drives an output stage (66) to generate a "trim fail" signal to disable the trim servo motor (44).
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