part 5b - lateral autopilot
DESCRIPTION
Lateral AutopilotsTRANSCRIPT
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Lateral Autopilots
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Introduction
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Autopilot uses:
For safety reasons
Lowers pilot workload (especially for long flights)
Types
Control or Hold certain flight parameter(s)
Perform navigational tasks
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Introduction
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Introduction
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Lateral Autopilots Bank/Roll Angle Hold Coordinated Roll Angle hold
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Bank Hold Autopilot
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Bank Angle Hold Prevents pilot having to constantly control roll angle.
Autopilot mode analysis/design, 2 important questions: Which type of control device do we use?
Ailerons
What type of feedback loop structure (sensor)? Roll Angle gyro
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Bank Angle Hold In simplest form it is a wing leveler An Attitude Sensor, roll gyro, is used to sense deviation Bank Angle feedback gives positive stiffness in roll and
stabilize the spiral mode. If the aircraft is held at some other attitude other than
wing level, additional control systems must be used to control sideslip and pitch rate, so that a coordinated turning motion is produced.
This control system can provide the inner loop for other autopilots, e.g. to maintain Fixed Heading etc.
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Bank Angle Hold Block Diagram
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Bank Angle Hold Block Diagram
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Bank Angle Hold
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Spiral Mode (𝑇𝑇 < 10) Roll Mode (𝑇𝑇 < 0.2) Dutch Roll Mode (𝜁𝜁 > 0.1)
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Coordinated Roll Angle hold Autopilot
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Coordinated Roll Angle hold
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Coordinated Roll Angle hold
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Heading Angle hold Autopilot
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Heading Angle hold Prevents pilot having to constantly control altitude during
the flight
Autopilot mode analysis/design, 2 important questions: Which type of control device do we use?
Rudder/Aileron
What type of feedback loop structure (sensor)? Sideslip Sensor, Gyro
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Heading Angle hold
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Heading Angle Hold
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Heading Angle Hold
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Heading Angle Hold
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Heading Angle Hold
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Heading Angle Hold
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Summary For each Hold autopilot there are two important
questions: Which type of control device? Which type of feedback? loop structure? sensors?
Keep controller as simple as possible Proportional only (if acceptable) PD, PI, Lead/Lag, etc…
The closed loop system must comply with the airworthiness requirements
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Summary Take into account the inner loop, when constructing the
outer loop. Keep in mind the possible effects on the closed loop
system of: Servo break frequency Flight condition (airspeed, altitude) etc...
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