pid control c code
universal PIDD2 controller
uses Takahashi PID form http://bestune.50megs.com/typeABC.htm : u(n) = u(n-1) + b0e(n) + b1e(n-1) + b2e(n-2) + b3e(n-3)
where b0 = kp + ki + kd + kd2; b1 = -kp -2kd -3kd2; b2 = kd + 3*kd2; b3 = -kd2;
antiwindup is implemented as u(n) limiter there is also exponential error filter option
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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Author : Kenshin - Michal Chovanec, 5 February 2015
use fixed point math, where one is represented as PID_FRACTION value
#define PID_FIXED_POINT 1
use floating point math
#define PID_FLOATING_POINT 1
enable error filtering
#define PID_ERROR_FILTER_ENABLE 1