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How I can define time limit for a control surface deflection

Designing a stable autopilot is one of the hardest things. Need help?

How I can define time limit for a control surface deflection

Postby mrostami » Thu May 31, 2018 8:50 pm

Is there anyway to simulate the slow movements of the control surfaces as they react rapidly. I mean defining time limit. I know it is possible to do this for the case o an autopilot but I don't know how to set this for the case of a regular action of the control surface without turning on the autopilot.
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Re: How to define time limit for a control surface deflectio

Postby Necolatis » Thu May 31, 2018 8:56 pm

For Yasim you just use the property rules. (same syntax as autopilot)
For JSBSim there is several components that does that. (actuator/kinematic)
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Re: How I can define time limit for a control surface deflec

Postby enrogue » Fri Jun 01, 2018 12:35 pm

For basic definition of how long a given control surface takes to move to full deflection, yasim has this built in (from wiki.flightgear.org/YASim):

control-speed
Some controls (most notably flaps and hydraulics) have maximum slew rates and cannot respond instantly to pilot input. This can be implemented with a control-speed tag, which defines a "transition time" required to slew through the full input range. Note that this tag is semi-deprecated, complicated control input filtering can be done much more robustly from a Nasal script.

control: Name of the control axis. See above.
transition-time: Time in seconds to slew through input range.

in practise this looks something like:

Code: Select all

         <flap0 start="0" end="1" lift="1.50" drag="1.3" />
         <control-input axis="/controls/flight/elevator" control="FLAP0" square="false"/>
         <control-input axis="/controls/flight/elevator-trim" control="FLAP0"/>
         <control-output control="FLAP0" prop="surface-positions/elevator-pos-norm"/>
         <control-speed control="FLAP0" transition-time="2"/>



As Necolatis says, if you want something more robust than this then property rules or nasal is the way to go
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