Pid.h

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//
// Copyright (c) 2009, Markus Rickert
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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//
 
#ifndef RL_MATH_PID_H
#define RL_MATH_PID_H
 
#include "Real.h"
 
namespace rl
{
    namespace math
    {
        template<typename T>
        class Pid
        {
        public:
            Pid() :
                e(0),
                kd(0),
                ki(0),
                kp(0),
                i(0)
            {
                
            }
            
            virtual ~Pid()
            {
                
            }
            
            T operator()(const T& x, const Real& dt)
            {
                T e = this->x - x;
                T p = this->kp * e;
                this->i += this->ki * e * dt;
                T d = this->kd * (e - this->e) / dt;
                this->e = e;
                return x + p + this->i + d;
            }
            
            void reset()
            {
                this->e = 0;
                this->i = 0;
            }
            
            T kd;
            
            T ki;
            
            T kp;
            
            T x;
            
        protected:
            
        private:
            T e;
            
            T i;
        };
    }
}
 
#endif // RL_MATH_PID_H