H59403 H19071
Roll Control Channel Block Diagram 570
22-11-0 Figure 6 (Sheet 1) Jun 20/85
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
506 Roll Control Channel Block Diagram
Feb 1/75 Figure 6 (Sheet 2) 22-11-0
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
good, and roll control wheel steering is not out of detent, THE AIL engage
switch is engaged, and voltage through the roll calibrator is present.
2) The 28-volt dc engage interlock power is routed through the autopilot disengage switches to the pitch engage interlock circuit and to one side of an AND gate circuit. Also, 28-volt dc roll control power is applied to one side of an AND gate in the control panel.
3) When the AIL engage switch is placed in the engage position and all other inputs to the roll channel (as shown on Fig. 7) are good, the roll channel output is an interlocks logic input to an AND gate in the control panel. This causes the AND gate logic function to be HIGH or 1. With both conditions 1 to the second AND gate, an output energizes the roll engage holding coil. The AIL engage switch is locked mechanically when the holding coil is not energized. When power is applied to the roll engage holding coil, the mechanical lock is removed. By engaging the AIL engage switch, the aileron force limiter switch contacts and the roll engage holding coil contacts are switched to a ground path through the circuit interrupter. When NAV mode is selected on autopilot control panel toggle switch the A/P STEERING switch is connected into the interlock circuit. The aileron force limiter switch contacts operate when the AIL engage switch is engaged.
4) Failure of any interlock signal will cause the AIL engage switch to disengage. Also, interruption of the interlock power sources, or instrument switching (as applicable) will cause the AIL engage switch to disengage. However, CWS inputs does not cause disengagement.
(b) Roll Attitude Hold 1) The roll channel operates in the roll attitude hold mode whenever the autopilot roll axis is engaged, and the mode select switch is in HDG OFF, nav mode select switch is in center off position, and the roll CWS is in detent. Upon engagement of the roll attitude hold mode, the roll computer is clamped by a motor clamp circuit, and the bank angle existing at the time of mode engagement is maintained. The bank angle limit for this mode is 32 degrees.
2) When the roll computer is clamped, changes to the airplane bank angle are sensed by the vertical gyro which will produce an error signal in the roll computer CT. This error signal is fed to summing point 9 and to an integrator (Fig. 6). (There is no other input to the integrator
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22-11-0 Page 28 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Feb 01/76
5C8 Roll Engage Logic Circuit
Jun 20/85 Figure 7 22-11-0
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
at this time because the synchronization feedback signal is grounded by energized switch RS-9.) The effect of the integrator is to increase the low-frequency gain of the roll computer CT signal into summing point 9 to decrease system standoff errors. Roll computer CT error signals and integrated error signals are summed with roll rate gyro signals at summing point 9. The rate gyro signals provide rate damping of the autopilot roll axis.
3) The signal resulting from the summation at summing point 9 is amplified by a preamplifier in the valve amplifier circuit and fed to an air data computer (ADC) Q-potentiometer. The ADC Q-potentiometer changes the forward gain of the signal fed to summing point 10 as an inverse function of airspeed. Gain scheduling as a function of airspeed provides for uniform autopilot control over the operational range of the airplane. The output signal from the ADC Q-potentiometer is fed to summing point 10 where it serves as the aileron command signal. The aileron command signal is summed with a feedback signal from the position transducer in the aileron actuator. Therefore, there will be an output from summing point 10 whenever the aileron command is not cancelled by a position feedback signal of opposing phase. The output signal from summing point 10 is amplified and demodulated by the valve amplifier and the resulting dc signal is applied to the electrohydraulic transfer valve in the selected aileron actuator. The aileron actuator will drive the airplane ailerons until the actuator position is such that the feedback signal from the actuator position transducer cancels the aileron command at summing point 10. Aileron displacement will be in the direction which causes the airplane to roll back toward the bank angle at which the roll computer is clamped. As the reference bank angle is approached, the roll computer CT error signal diminishes and, correspondingly, the aileron displacement decreases. The net result is zero aileron displacement when the reference bank angle is restored. The preceding sequence of events occurs whenever the airplane deviates from the clamped bank angle reference with the result that a reference roll attitude is maintained. Roll attitude hold mode automatically disengages if any of the previously mentioned modes or conditions are initiated.
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