Roy Vegard Ovesen wrote:
On Friday 19 August 2005 23:58, Hans-Georg Wunder wrote:
Hi all,
I try to configure a P-Controller, but I have problems with the
anti-windup logic:
The velocity form of the PID control algorithm _needs_ to have an integral
component. If you need to use a P only controller, try the
<pi-simple-controller>.
Snip! ...
I took a P only controlller to simplify the problem.
Snip! ...
I think, this is not okay. delta_u_n = 0; has to be replaced by
something like that
delta_u_n=u_max - u_n_1;
It doesn't work !!! :}}}}
But after a looooooooooot of testing I found a solution:
// Integrator anti-windup logic:
if ( delta_u_n > (u_max - u_n_1) ) {
// We have to add the maxium, which is posibble and then
// to reduce the input value for the next cylcle accordingly
ep_n = (ep_n * u_max )/(delta_u_n+ u_n_1 );
if ( Td > 0.0 ) edf_n = (edf_n * u_max ) / ( delta_u_n +
u_n_1 );
delta_u_n =u_max - u_n_1 ;
// delta_u_n = u_max - u_n_1;
// ep_n = delta_u_n / Kp;
//ep_n =- u_max/Kp;
if ( debug ) cout << "Max saturation " << " New delta_u_n
= " << delta_u_n << " New ep_n = "<< ep_n << " ew edf_n = " << edf_n <<
endl;
} else if ( delta_u_n < (u_min - u_n_1) ) {
// We have to add the maxium, which is posibble and then
// to reduce the input value for the next cylcle accordingly
ep_n = (ep_n * u_min )/( delta_u_n + u_n_1 );
if ( Td > 0.0 ) edf_n = (edf_n * u_min ) /(delta_u_n +
u_n_1 ) ;
delta_u_n =u_min - u_n_1 ;
// delta_u_n = u_min - u_n_1;
// ep_n = delta_u_n / Kp;
//ep_n =- u_min/Kp;
if ( debug ) cout << "Min saturation " << " New delta_u_n
= " << delta_u_n << " New ep_n = "<< ep_n << " New edf_n = " << edf_n <<
endl;
}
I tested it for a P and a PI-controller. I haven't tested yet the
D-part, but I hope, it will work too
Any comments are welcome
Hans-Georg
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