/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

 Header:       FGPID.h
 Author:       Jon Berndt
 Date started: 6/17/2006

 ------------- Copyright (C) 2006 by Jon S. Berndt, jsb@hal-pc.org -------------

 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by the Free Software
 Foundation; either version 2 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 Lesser General Public License for more
 details.

 You should have received a copy of the GNU Lesser General Public License along with
 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 Place - Suite 330, Boston, MA  02111-1307, USA.

 Further information about the GNU Lesser General Public License can also be found on
 the world wide web at http://www.gnu.org.

HISTORY
--------------------------------------------------------------------------------
Initial Code 6/17/2006 JSB

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SENTRY
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

#ifndef FGPID_H
#define FGPID_H

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

#include "FGFCSComponent.h"
#include <input_output/FGXMLElement.h>
#include <string>

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
DEFINITIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

#define ID_PID "$Id: FGPID.h,v 1.4 2008/07/22 08:49:16 ehofman Exp $"

using std::string;

using std::string;

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FORWARD DECLARATIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

namespace JSBSim {

class FGFCS;

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DOCUMENTATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

/** Encapsulates a PID control component for the flight control system.

<h3>Configuration Format:</h3>

@code
<pid name="{string}">
  <kp> {number} </kp>
  <ki> {number} </ki>
  <kd> {number} </kd>
  <trigger> {string} </trigger>
</pid>
@endcode

<h3>Configuration Parameters:</h3>
<pre>

  kp      - Proportional constant, default value 0.
  ki      - Integrative constant, default value 0.
  kd      - Derivative constant, default value 0.
  trigger - Property which is used to sense wind-up, optional.

</pre>

    @author Jon S. Berndt
    @version $Revision: 1.4 $
*/

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DECLARATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

class FGPID  : public FGFCSComponent
{
public:
  FGPID(FGFCS* fcs, Element* element);
  ~FGPID();

  bool Run (void);

private:
  double dt;
  FGPropertyManager *Trigger;
  double Kp, Ki, Kd;
  double I_out_total;
  double Input_prev, Input_prev2;
  double KpPropertySign;
  double KiPropertySign;
  double KdPropertySign;
  FGPropertyManager* KpPropertyNode;
  FGPropertyManager* KiPropertyNode;
  FGPropertyManager* KdPropertyNode;

  void Debug(int from);
};
}
#endif
