Chun Feng Huang / PID

New PID library with digital anti-windup and process control

Fork of PID_modified by Chun Feng Huang

PID.h@7:6f0e5de35b48, 2017-03-30 (annotated)

Committer:
benson516
Date:
Thu Mar 30 07:52:35 2017 +0000
Revision:
7:6f0e5de35b48
Parent:
5:016c99bb877f 
New PID library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
weisnail 0:7f9b4ca968ae 1 #ifndef PID_H
weisnail 0:7f9b4ca968ae 2 #define PID_H
benson516 7:6f0e5de35b48 3 //
benson516 7:6f0e5de35b48 4 #include "FILTER_LIB.h"
weisnail 0:7f9b4ca968ae 5
weisnail 0:7f9b4ca968ae 6 class PID{
benson516 7:6f0e5de35b48 7 public:
benson516 7:6f0e5de35b48 8
benson516 7:6f0e5de35b48 9 // Sampling time
benson516 7:6f0e5de35b48 10 float Ts;
benson516 7:6f0e5de35b48 11 //
benson516 7:6f0e5de35b48 12 bool enable;
benson516 7:6f0e5de35b48 13
benson516 7:6f0e5de35b48 14 // Flags
benson516 7:6f0e5de35b48 15 bool is_limiting_command;
benson516 7:6f0e5de35b48 16 bool is_limiting_output;
benson516 7:6f0e5de35b48 17 //
benson516 7:6f0e5de35b48 18 bool is_using_integral; // Determine if the integral control is going to be used.
benson516 7:6f0e5de35b48 19 bool is_using_derivative; // Determine if the derivative control is going to be used.
benson516 7:6f0e5de35b48 20 //
benson516 7:6f0e5de35b48 21 bool is_using_outSource_d_error; // Determine whether using the signal for d_error or using numerical derivative to derive d_error from error.
benson516 7:6f0e5de35b48 22 //
benson516 7:6f0e5de35b48 23 bool is_antiWindUp;
benson516 7:6f0e5de35b48 24
benson516 7:6f0e5de35b48 25 // Parameters
benson516 7:6f0e5de35b48 26 // Feedback gain
benson516 7:6f0e5de35b48 27 float Kp;
benson516 7:6f0e5de35b48 28 float Ki;
benson516 7:6f0e5de35b48 29 float Kd;
benson516 7:6f0e5de35b48 30 //
benson516 7:6f0e5de35b48 31 // float Ka;
benson516 7:6f0e5de35b48 32
benson516 7:6f0e5de35b48 33 // States
benson516 7:6f0e5de35b48 34 float error;
benson516 7:6f0e5de35b48 35 float d_error;
benson516 7:6f0e5de35b48 36 float error_int;
benson516 7:6f0e5de35b48 37 //
benson516 7:6f0e5de35b48 38 float error_int_increment; // error_int += error_int_increment;
weisnail 0:7f9b4ca968ae 39
benson516 7:6f0e5de35b48 40 // Input signal
benson516 7:6f0e5de35b48 41 float command;
benson516 7:6f0e5de35b48 42 float feedbackValue;
benson516 7:6f0e5de35b48 43 // Output signal
benson516 7:6f0e5de35b48 44 float output;
benson516 7:6f0e5de35b48 45 // Error by saturation
benson516 7:6f0e5de35b48 46 float delta_output; // Error by saturation
benson516 7:6f0e5de35b48 47
benson516 7:6f0e5de35b48 48
benson516 7:6f0e5de35b48 49 PID(float Kp_in, float Ki_in, float Kd_in, float Sampletime_in);
benson516 7:6f0e5de35b48 50 // Process controller
benson516 7:6f0e5de35b48 51 void start(); // Run
benson516 7:6f0e5de35b48 52 void pause(); // Stop updating but no reset
benson516 7:6f0e5de35b48 53 void stop(); // Stop and reset
benson516 7:6f0e5de35b48 54 void reset(); // Reset all the states to initial values.
benson516 7:6f0e5de35b48 55 //
benson516 7:6f0e5de35b48 56 void EnableAntiWindUp(float Ka_in);
benson516 7:6f0e5de35b48 57 //
benson516 7:6f0e5de35b48 58 void set_PID_gains(float Kp_in, float Ki_in, float Kd_in); // Setting Kp, Ki, and Kd
benson516 7:6f0e5de35b48 59 void SetInputLimits(float inputLimits_H_in, float inputLimits_L_in);
benson516 7:6f0e5de35b48 60 void SetOutputLimits(float outputLimits_H_in, float outputLimits_L_in);
weisnail 0:7f9b4ca968ae 61
benson516 7:6f0e5de35b48 62 // Main function for computing the PID
benson516 7:6f0e5de35b48 63 void set_d_error(float d_error_in); // Insert d_error before iteration.
benson516 7:6f0e5de35b48 64 void iterateOnce(float command_in, float feedbackValue_in);
benson516 7:6f0e5de35b48 65 void iterateOnce_noAntiWindUP(float command_in, float feedbackValue_in);
benson516 7:6f0e5de35b48 66
benson516 7:6f0e5de35b48 67 // Anti-windup method
benson516 7:6f0e5de35b48 68 // Method 1: Separated operation for anti-windup
benson516 7:6f0e5de35b48 69 void Saturation_output();
benson516 7:6f0e5de35b48 70 void AntiWindUp(float delta); // delta_V = V - V_sat
benson516 7:6f0e5de35b48 71 // Method 2: Single anti-windup operation
benson516 7:6f0e5de35b48 72 void Saturation_AntiWindUp();
benson516 7:6f0e5de35b48 73 //
benson516 7:6f0e5de35b48 74
benson516 7:6f0e5de35b48 75 private:
benson516 7:6f0e5de35b48 76
benson516 7:6f0e5de35b48 77 // Derivative
benson516 7:6f0e5de35b48 78 Derivative_appr derivative_error;
benson516 7:6f0e5de35b48 79
benson516 7:6f0e5de35b48 80 // Saturation
benson516 7:6f0e5de35b48 81 Saturation SAT_command;
benson516 7:6f0e5de35b48 82 Saturation SAT_output;
benson516 7:6f0e5de35b48 83
benson516 7:6f0e5de35b48 84 // Small over-bound value for numerical stability
benson516 7:6f0e5de35b48 85 float overBound_value; // Small positive value
weisnail 0:7f9b4ca968ae 86
weisnail 0:7f9b4ca968ae 87 };
weisnail 0:7f9b4ca968ae 88
benson516 7:6f0e5de35b48 89 #endif /* PID_H*/