#include <FGGain.h>
Inherits FGFCSComponent.
<pure_gain name="name"> <input> {[-]property} </input> <gain> {property name | value} </gain> [<clipto> <min> {property name | value} </min> <max> {property name | value} </max> </clipto>] [<output> {property} </output>] </pure_gain>
Example:
<pure_gain name="Roll AP Wing Leveler">
<input>fcs/attitude/sensor/phi-rad</input>
<gain>2.0</gain>
<clipto>
<min>-0.255</min>
<max>0.255</max>
</clipto>
</pure_gain>
Note: the input property name may be immediately preceded by a minus sign to invert that signal.
The scheduled gain component multiplies the input by a variable gain that is dependent on another property (such as qbar, altitude, etc.). The lookup mapping is in the form of a table. This kind of component might be used, for example, in a case where aerosurface deflection must only be commanded to acceptable settings - i.e at higher qbar the commanded elevator setting might be attenuated. The form of the scheduled gain component specification is:
<scheduled_gain name="name"> <input> {[-]property} </input> <table> <tableData> ... </tableData> </table> [<clipto> <min> {[-]property name | value} </min> <max> {[-]property name | value} </max> </clipto>] [<gain> {property name | value} </gain>] [<output> {property} </output>] </scheduled_gain>
Example:
<scheduled_gain name="Scheduled Steer Pos Deg">
<input>fcs/steer-cmd-norm</input>
<table>
<independentVar>velocities/vg-fps</independentVar>
<tableData>
10.0 80.0
50.0 15.0
150.0 2.0
</tableData>
</table>
<gain>0.017</gain>
<output>fcs/steer-pos-rad</output>
</scheduled_gain>
An overall GAIN may be supplied that is multiplicative with the scheduled gain.
Note: the input property name may be immediately preceded by a minus sign to invert that signal.
In the example above, we see the utility of the overall gain value in effecting a degrees-to-radians conversion.
The aerosurface scale component is a modified version of the simple gain component. The purpose for this component is to take control inputs from the domain minimum and maximum, as specified (or from -1 to +1 by default) and scale them to map to a specified range. This can be done, for instance, to match the component outputs to the expected inputs to a flight control system.
The zero_centered element dictates whether the domain-to-range mapping is linear or centered about zero. For example, if zero_centered is false, and if the domain or range is not symmetric about zero, and an input value is zero, the output will not be zero. Let's say that the domain is min=-2 and max=+4, with a range of -1 to +1. If the input is 0.0, then the "normalized" input is calculated to be 33% of the way from the minimum to the maximum. That input would be mapped to an output of -0.33, which is 33% of the way from the range minimum to maximum. If zero_centered is set to true (or 1) then an input of 0.0 will be mapped to an output of 0.0, although if either the domain or range are unsymmetric about 0.0, then the scales for the positive and negative portions of the input domain (above and below 0.0) will be different. The zero_centered element is true by default. Note that this feature may be important for some control surface mappings, where the maximum upper and lower deflections may be different, but where a zero setting is desired to be the "undeflected" value, and where full travel of the stick is desired to cause a full deflection of the control surface.
The form of the aerosurface scaling component specification is:
<aerosurface_scale name="name"> <input> {[-]property name} </input> <domain> <min> {value} </min> <!-- If omitted, default is -1.0 -> <max> {value} </max> <!-- If omitted, default is 1.0 -> </domain> <range> <min> {value} </min> <!-- If omitted, default is 0 -> <max> {value} </max> <!-- If omitted, default is 0 -> </range> <zero_centered< value </zero_centered> [<clipto> <min> {[-]property name | value} </min> <max> {[-]property name | value} </max> </clipto>] [<gain> {property name | value} </gain>] [<output> {property} </output>] </aerosurface_scale>
Note: the input property name may be immediately preceded by a minus sign to invert that signal.
For instance, the normal and expected ability of a pilot to push or pull on a control stick is about 50 pounds. The input to the pitch channel block diagram of a flight control system is often in units of pounds. Yet, the joystick control input usually defines a span from -1 to +1. The aerosurface_scale form of the gain component maps the inputs to the desired output range. The example below shoes a simple aerosurface_scale component that maps the joystick input to a range of +/- 50, which represents pilot stick force in pounds for the F-16.
<aerosurface_scale name="Pilot input"> <input>fcs/elevator-cmd-norm</input> <range> <min> -50 </min> <!-- If omitted, default is 0 -> <max> 50 </max> <!-- If omitted, default is 0 -> </range> </aerosurface_scale>
Definition at line 221 of file FGGain.h.
Public Member Functions | |
| FGGain (FGFCS *fcs, Element *element) | |
| bool | Run (void) |
1.5.5