737NG的马赫配平在AP衔接前和衔接后工作逻辑的区别？

民航AV男 · 发表于 2015-5-17 22:12:48

看手册没看明白，

AutopilotDisengaged

When the autopilot is disengaged, the feel andcentering unit supplies an input to the elevator power control units (PCU). Thismoves the elevators. A signal from the mach trim actuator tells the FCC how muchit moves.

AutopilotEngaged

When the autopilot is engaged, the feel andcentering unit cannot supply an input to the elevator PCUs. This is because theautopilot elevator actuators lock the elevator input torque tube. This will notlet the input arms of the PCUs move. However, the mach trim actuator will turnthe neutral shift sensor. The signals from the neutral shift sensor and theelevator position sensor go to the FCC. The FCC knows that the neutral shiftposition changes and the elevator position does not move. The FCC calculates anautopilot signal which then causes the autopilot elevator actuators to move theinput to the PCUs.

是在AP衔接之前FCC→马赫配平作动筒→升降舵定中组件→PCU→控制升降舵；AP衔接之后FCC→AP作动筒→PCU→升降舵吗？
那马赫配平作动筒在AP衔接之后的作用是什么，就是从定中轴传感器和升降舵位置传感器得到升降舵位置信号来反馈给FCC的吗？那如何实现马赫配平？
求各位大神指教！