摘要 |
Four actuators are instructed to move to a condition indicated by a demand line 81 . Their actual conditions are indicated by four arrows. The method determines if the range 84 of actual conditions exceeds a threshold value, representing an unacceptable mismatch of actuator positions. This comparison is used to establish further demand instructions. For example, if the range is too great, and the average 82 is below the demand line 81 , the devices are instructed to move to the upper extreme position at 88 . If the average position 82 is above the demand line 81 , the devices are instructed to move to the lower end of the range, at 90. This results in the actuator positions moving together, as they also move toward the demand line 81 , reducing risks associated with actuator mismatches.
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