FlyByWireCpp/FlyByWire.cpp
2019-11-17 14:20:19 +01:00

133 lines
2.7 KiB
C++

#include "FlyByWire.hpp"
// =============================================================================
// General fly-by-wire helper functions
// =============================================================================
namespace FlyByWire
{
Real Hdg_err(Real tgt, Real hdg)
{
Real err = tgt - hdg;
if(err > Real(M_PI))
return err - Real(M_PI*Real(2.));
else if(err < Real(-M_PI))
return err + Real(M_PI*Real(2.));
else
return err;
}
Real Hdg_err_deg(Real tgt, Real hdg)
{
Real err = tgt - hdg;
if(err > Real(180.))
return err - Real(360.);
else if(err < Real(-180.))
return err + Real(360.);
else
return err;
}
Real Vote(Real a, Real b, Real c)
{
Real tmp;
if(c < a)
{
tmp = c;
c = a;
a = tmp;
}
if(b < a)
{
tmp = b;
b = a;
a = tmp;
}
if(c < b)
{
tmp = c;
c = b;
b = tmp;
}
return b;
}
Real Deadzone(Real x, Real a)
{
if(fabs(x) >= a)
return x;
else
return Real(0.);
}
Real Sat1(Real x, Real a, Real b)
{
if(x < a)
return a;
else if(x > b)
return b;
else
return x;
}
Real Ratelim(Real x_n, Real y_n_1, Real dy_dt_min, Real dy_dt_max, Real dt)
{
Real dydt = (x_n - y_n_1)/dt; // candidate derivative
if(dydt < dy_dt_min) // minimum derivative
return y_n_1 + dy_dt_min*dt;
else if(dydt > dy_dt_max) // maximum derivative
return y_n_1 + dy_dt_max*dt;
else // derivative within bounds
return x_n;
}
RateLimiter::RateLimiter(Real dy_dt_min_, Real dy_dt_max_, Real dt_, Real y_)
: dy_dt_min(dy_dt_min_),
dy_dt_max(dy_dt_max_),
dt(dt_),
y_n_1(y_)
{}
Real RateLimiter::Filter(Real x_n)
{
Real y_n = Ratelim(x_n, y_n_1, dy_dt_min, dy_dt_max, dt);
y_n_1 = y_n;
return y_n;
}
Real Heaviside(Real x)
{
return (x >= Real(0.)) ? Real(1.) : Real(0.);
}
// =============================================================================
// IRR Filters from the continuous Laplace transfer function.
// =============================================================================
Integrator1::Integrator1(Real Ts_, Real y_, Real lower_bound_, Real upper_bound_)
: Ts(Ts_),
lower_bound(lower_bound_),
upper_bound(upper_bound_)
{
SetState(y_, Real(0.));
}
void Integrator1::SetState(Real y_, Real x_)
{
y_n_1 = y_;
x_n_1 = x_;
}
Real Integrator1::Filter(Real x_n)
{
Real y_n = y_n_1 + (x_n + x_n_1)*Ts/Real(2.);
y_n = Sat1(y_n, lower_bound, upper_bound);
x_n_1 = x_n;
y_n_1 = y_n;
return y_n;
}
}// namespace FlyByWire