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Autopilot configuration reference: Difference between revisions
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pid-controller and pi-simple-controller
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(pid-controller and pi-simple-controller) |
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This page serves as a reference for the elements of FlightGear xml autopilot configuration files. It describes all elements available within the autopilot configuration file supported in the bleeding edge CVS sources. Some of the elements may not be available in the current release version of FlightGear. | This page serves as a reference for the elements of FlightGear xml autopilot configuration files. It describes all elements available within the autopilot configuration file supported in the bleeding edge CVS sources. Some of the elements may not be available in the current release version of FlightGear. | ||
Refer to [[Howto: | Refer to [[Howto: Design an autopilot]] as a guide how to use these elements. | ||
== Structure Of a Configuration File == | == Structure Of a Configuration File == | ||
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* <predict-simple> | * <predict-simple> | ||
== | == Common Elements Used By All Filters == | ||
== | === Input Values === | ||
=== filter | === Output Values === | ||
== filter == | |||
==== gain ==== | ==== gain ==== | ||
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=== pid-controller === | === pid-controller === | ||
The [[http://en.wikipedia.org/wiki/PID_controller PID controller]] is the swiss army knife of automation and this implementation is suitable for most situations. It has a builtin anti-windup logic, usage of <max> and <min> elements for output clamp is mandatory. Most important thing to know is that this controller does not compute absolute output values but an offset from the current value of the output property. This can lead to unexpected behavior if the current value of the output property is unknown when the controller is enabled. This behavior is different to that of the pi-simple-controller. | |||
The xml element creating a pid controller is '''<pid-controller>'''. | |||
Legal elements are (FIXME: this should appear as a table) | |||
Kp - the overall gain for the proportional, integral and derivative part | |||
Ti - integrator time | |||
Td - derivator time | |||
Ts - sampling interval (default: sample at frame rate) | |||
alpha - scaling factor for Td (defaults to 0.1) | |||
beta - reference weighing factor for the proportional component (defaults to 1.0) | |||
gamma - reference weighing factor for the derivate component (defaults to 0.0) | |||
=== pi-simple-controller === | === pi-simple-controller === | ||
This controller implements a PI controller. Other than the PID controller, it computes absolute output values, regardless of the value of the output property. It can by configured as an I-only, P-only or PI-controller. It has anti windup logic if <min> and <max> elements are present. | |||
The xml element creating a PI controller is '''<pi-simple-controller>''' | |||
Legal elements are (FIXME: this should appear as a table) | |||
Kp - gain of the proportional compoment | |||
Ki - gain of the integrator component | |||
=== predict-simple === | === predict-simple === | ||
=== logic === | |||