![](/media/cache/img/default_profile.jpg.50x50_q85.jpg)
follow wall 1
Diff: PID/PID.h
- Revision:
- 0:b703833f6795
diff -r 000000000000 -r b703833f6795 PID/PID.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/PID/PID.h Tue Apr 08 13:23:06 2014 +0000 @@ -0,0 +1,213 @@ +/** + * @author Aaron Berk + * + * @section LICENSE + * + * Copyright (c) 2010 ARM Limited + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + * + * @section DESCRIPTION + * + * A PID controller is a widely used feedback controller commonly found in + * industry. + * + * This library is a port of Brett Beauregard's Arduino PID library: + * + * http://www.arduino.cc/playground/Code/PIDLibrary + * + * The wikipedia article on PID controllers is a good place to start on + * understanding how they work: + * + * http://en.wikipedia.org/wiki/PID_controller + * + * For a clear and elegant explanation of how to implement and tune a + * controller, the controlguru website by Douglas J. Cooper (who also happened + * to be Brett's controls professor) is an excellent reference: + * + * http://www.controlguru.com/ + */ + +#ifndef PID_H +#define PID_H + +/** + * Includes + */ +#include "mbed.h" + +/** + * Defines + */ +#define MANUAL_MODE 0 +#define AUTO_MODE 1 + +/** + * Proportional-integral-derivative controller. + */ +class PID { + +public: + + /** + * Constructor. + * + * Sets default limits [0-3.3V], calculates tuning parameters, and sets + * manual mode with no bias. + * + * @param Kc - Tuning parameter + * @param tauI - Tuning parameter + * @param tauD - Tuning parameter + * @param interval PID calculation performed every interval seconds. + */ + PID(float Kc, float tauI, float tauD, float interval); + + /** + * Scale from inputs to 0-100%. + * + * @param InMin The real world value corresponding to 0%. + * @param InMax The real world value corresponding to 100%. + */ + void setInputLimits(float inMin , float inMax); + + /** + * Scale from outputs to 0-100%. + * + * @param outMin The real world value corresponding to 0%. + * @param outMax The real world value corresponding to 100%. + */ + void setOutputLimits(float outMin, float outMax); + + /** + * Calculate PID constants. + * + * Allows parameters to be changed on the fly without ruining calculations. + * + * @param Kc - Tuning parameter + * @param tauI - Tuning parameter + * @param tauD - Tuning parameter + */ + void setTunings(float Kc, float tauI, float tauD); + + /** + * Reinitializes controller internals. Automatically + * called on a manual to auto transition. + */ + void reset(void); + + /** + * Set PID to manual or auto mode. + * + * @param mode 0 -> Manual + * Non-zero -> Auto + */ + void setMode(int mode); + + /** + * Set how fast the PID loop is run. + * + * @param interval PID calculation peformed every interval seconds. + */ + void setInterval(float interval); + + /** + * Set the set point. + * + * @param sp The set point as a real world value. + */ + void setSetPoint(float sp); + + /** + * Set the process value. + * + * @param pv The process value as a real world value. + */ + void setProcessValue(float pv); + + /** + * Set the bias. + * + * @param bias The bias for the controller output. + */ + void setBias(float bias); + + /** + * PID calculation. + * + * @return The controller output as a float between outMin and outMax. + */ + float compute(void); + + //Getters. + float getInMin(); + float getInMax(); + float getOutMin(); + float getOutMax(); + float getInterval(); + float getPParam(); + float getIParam(); + float getDParam(); + +private: + + bool usingFeedForward; + bool inAuto; + + //Actual tuning parameters used in PID calculation. + float Kc_; + float tauR_; + float tauD_; + + //Raw tuning parameters. + float pParam_; + float iParam_; + float dParam_; + + //The point we want to reach. + float setPoint_; + //The thing we measure. + float processVariable_; + float prevProcessVariable_; + //The output that affects the process variable. + float controllerOutput_; + float prevControllerOutput_; + + //We work in % for calculations so these will scale from + //real world values to 0-100% and back again. + float inMin_; + float inMax_; + float inSpan_; + float outMin_; + float outMax_; + float outSpan_; + + //The accumulated error, i.e. integral. + float accError_; + //The controller output bias. + float bias_; + + //The interval between samples. + float tSample_; + + //Controller output as a real world value. + volatile float realOutput_; + +}; + +#endif /* PID_H */