AVR449: pid.h File Reference

#define FALSE 0

Definition at line 58 of file pid.h.

Referenced by ActualDirectionUpdate(), CommutationTicksUpdate(), HallChangeISR(), main(), MotorSynchronizedUpdate(), and Timer1OverflowISR().

#define MAX_I_TERM (MAX_LONG / 2)

Definition at line 55 of file pid.h.

Referenced by pid_Controller(), and pid_Init().

#define MAX_INT INT16_MAX

Maximum values.

Needed to avoid sign/overflow problems

Definition at line 53 of file pid.h.

Referenced by pid_Controller(), and pid_Init().

#define MAX_LONG INT32_MAX

Definition at line 54 of file pid.h.

#define SCALING_FACTOR 256

Definition at line 25 of file pid.h.

Referenced by pid_Controller().

#define TRUE (!FALSE)

Definition at line 59 of file pid.h.

Referenced by CommutationTicksUpdate(), and MotorSynchronizedUpdate().

typedef struct PID_DATA pidData_t

PID Status.

Setpoints and data used by the PID control algorithm

int16_t pid_Controller	(	int16_t	setPoint,
		int16_t	processValue,
		struct PID_DATA *	pid_st
	)

PID control algorithm.

Calculates output from setpoint, process value and PID status.

Parameters:

	setPoint	Desired value.
	processValue	Measured value.
	pid_st	PID status struct.

Definition at line 64 of file pid.c.

References PID_DATA::D_Factor, PID_DATA::I_Factor, PID_DATA::lastProcessValue, MAX_I_TERM, MAX_INT, PID_DATA::maxError, PID_DATA::maxSumError, PID_DATA::P_Factor, SCALING_FACTOR, and PID_DATA::sumError.

Referenced by SpeedController().

00065 {
00066   int16_t error, p_term, d_term;
00067   int32_t i_term, ret, temp;
00068 
00069   error = setPoint - processValue;
00070 
00071   // Calculate Pterm and limit error overflow
00072   if (error > pid_st->maxError){
00073     p_term = MAX_INT;
00074   }
00075   else if (error < -pid_st->maxError){
00076     p_term = -MAX_INT;
00077   }
00078   else{
00079     p_term = pid_st->P_Factor * error;
00080   }
00081 
00082   // Calculate Iterm and limit integral runaway
00083   temp = pid_st->sumError + error;
00084   if(temp > pid_st->maxSumError){
00085     i_term = MAX_I_TERM;
00086     pid_st->sumError = pid_st->maxSumError;
00087   }
00088   else if(temp < -pid_st->maxSumError){
00089     i_term = -MAX_I_TERM;
00090     pid_st->sumError = -pid_st->maxSumError;
00091   }
00092   else{
00093     pid_st->sumError = temp;
00094     i_term = pid_st->I_Factor * pid_st->sumError;
00095   }
00096 
00097   // Calculate Dterm
00098   d_term = pid_st->D_Factor * (pid_st->lastProcessValue - processValue);
00099 
00100   pid_st->lastProcessValue = processValue;
00101 
00102   ret = (p_term + i_term + d_term) / SCALING_FACTOR;
00103   if(ret > MAX_INT){
00104     ret = MAX_INT;
00105   }
00106   else if(ret < -MAX_INT){
00107     ret = -MAX_INT;
00108   }
00109 
00110   return((int16_t)ret);
00111 }

void pid_Init	(	int16_t	p_factor,
		int16_t	i_factor,
		int16_t	d_factor,
		struct PID_DATA *	pid
	)

Initialisation of PID controller parameters.

Initialise the variables used by the PID algorithm.

Parameters:

	p_factor	Proportional term.
	i_factor	Integral term.
	d_factor	Derivate term.
	pid	Struct with PID status.

Definition at line 40 of file pid.c.

References PID_DATA::D_Factor, PID_DATA::I_Factor, PID_DATA::lastProcessValue, MAX_I_TERM, MAX_INT, PID_DATA::maxError, PID_DATA::maxSumError, PID_DATA::P_Factor, and PID_DATA::sumError.

Referenced by main().

00042 {
00043   // Start values for PID controller
00044   pid->sumError = 0;
00045   pid->lastProcessValue = 0;
00046   // Tuning constants for PID loop
00047   pid->P_Factor = p_factor;
00048   pid->I_Factor = i_factor;
00049   pid->D_Factor = d_factor;
00050   // Limits to avoid overflow
00051   pid->maxError = MAX_INT / (pid->P_Factor + 1);
00052   pid->maxSumError = MAX_I_TERM / (pid->I_Factor + 1);
00053 }

void pid_Reset_Integrator ( pidData_t * pid_st )

Resets the integrator.

Calling this function will reset the integrator in the PID controller.

Definition at line 117 of file pid.c.

References PID_DATA::sumError.

Referenced by CommutationTicksUpdate(), and FaultProtectionISR().

00118 {
00119   pid_st->sumError = 0;
00120 }

pid.h File Reference

Detailed Description

Data Structures

Defines

Typedefs

Functions

Define Documentation

Typedef Documentation

Function Documentation


Data Structures
struct	PID_DATA
	PID Status. More...
Defines
#define	FALSE 0
#define	MAX_I_TERM (MAX_LONG / 2)
#define	MAX_INT INT16_MAX
	Maximum values.
#define	MAX_LONG INT32_MAX
#define	SCALING_FACTOR 256
#define	TRUE (!FALSE)
Typedefs
typedef PID_DATA	pidData_t
	PID Status.
Functions
int16_t	pid_Controller (int16_t setPoint, int16_t processValue, struct PID_DATA *pid_st)
	PID control algorithm.
void	pid_Init (int16_t p_factor, int16_t i_factor, int16_t d_factor, struct PID_DATA *pid)
	Initialisation of PID controller parameters.
void	pid_Reset_Integrator (pidData_t *pid_st)
	Resets the integrator.