| 摘要 |
A positioning device for a critical aircraft surface, such as a stabilizing elevator in a helicopter, includes a pair of reversible electric jack-screw type actuators acting in series, each being controlled in a closed-loop fashion by separate electronic hardware, the position of each as well as the rate of change thereof being compared with the other, against limits which, according to the invention, are relatively broader at low speeds and are tightened at higher speeds. If either of the positions or the rate of change of positions of the two actuators fail to track within the variable threshold disparity, an alarm condition is manifested and the actuators are disconnected from automatic control and rendered operable by manual control. |
