discrete-lib.c File Reference

Discrete Control Law Implementation Library. More...

#include <stdlib.h>
#include "discrete-lib.h"

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Macros
#define	SATURATE(val, lo, hi)   val < lo ? lo : (val > hi ? hi : val)
	Saturates a value.

Functions
static double	EvaluateBiquad (Biquad *sys, double input)
void	IntegratorInit (Proportional gain, double timestep, Integrator *result)
void	DifferentiatorInit (Proportional gain, double timestep, Differentiator *result)
double	Cascade (double input, Biquad sys[], int size, double lower_lim, double upper_lim)
double	Integrate (double input, Integrator *term, double lower_lim, double upper_lim)
double	Differentiate (double input, Differentiator *term, double lower_lim, double upper_lim)
double	PID (double input, Proportional *p, Integrator *i, Differentiator *d, double lower_lim, double upper_lim)

Detailed Description

Discrete Control Law Implementation Library.

Author

Anti-Sway Team: Nguyen, Tri; Espinola, Malachi; Tevy, Vattanary; Hokenstad, Ethan; Neff, Callen)

Version

0.1

Date

2024-06-03

Copyright

Copyright (c) 2024

Macro Definition Documentation

SATURATE

#define SATURATE	(		val,
			lo,
			hi )   val < lo ? lo : (val > hi ? hi : val)

Saturates a value.

Saturates a value to be between some low and high value

Parameters

val	The numerical value to saturate
lo	The numerical lower limit
hi	The numerical upper limit

Evaluates to val iff lo <= val <= hi, lo iff val < lo and hi iff val > hi

Function Documentation

Cascade()

double Cascade ( double input, Biquad sys[], int size, double lower_lim, double upper_lim )

inline

Executes a dynamic, discrete time system by using its biquad decomposition.

Parameters

input	The input to the system
sys	The system, as an array of biquads
size	The size of sys
lower_lim	The lower saturation limit of the system
upper_lim	The upper saturation limit of the system

Returns

The output of the system given the input

Precondition

The input is the next sampled value of the input to the system

Postcondition

The system is updated with current/past calculated values

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Differentiate()

double Differentiate ( double input, Differentiator * term, double lower_lim, double upper_lim )

inline

Timesteps a Differentiation

Parameters

input	The input to the differentiator
term	A pointer to an differentiator term
lower_lim	The lower saturation limit of the system
upper_lim	The upper saturation limit of the system

Returns

The output of the differentiator given the input

Precondition

The input is the next sampled value of the input to the system

Postcondition

term is updated with current/past calculated values

DifferentiatorInit()

void DifferentiatorInit	(	Proportional	gain,
		double	timestep,
		Differentiator *	result )

Initializes a Differentiator

Parameters

gain	The gain to assign the differentiator
timestep	The timestep to approximate the differentiator
result	A return parameter, which becomes the differentiator with the gain and timestep

Returns

result, which will be an differentiator with a gain gain, and the timestep

EvaluateBiquad()

static double EvaluateBiquad ( Biquad * sys, double input )

inlinestatic

Evaluates a singular dynamic distrete time biquad within a system, which itself is a system.

Parameters

sys	The system
input	The system's input

Returns

The output of the system

Precondition

The input is the next sampled value of the input to the system

Postcondition

The system is updated with current/past calculated values

Integrate()

double Integrate ( double input, Integrator * term, double lower_lim, double upper_lim )

inline

Timesteps an Integration

Parameters

input	The input to the integrator
term	A pointer to an integrator term
lower_lim	The lower saturation limit of the system
upper_lim	The upper saturation limit of the system

Returns

The output of the integrator given the input

Precondition

The input is the next sampled value of the input to the system

Postcondition

term is updated with current/past calculated values

IntegratorInit()

void IntegratorInit	(	Proportional	gain,
		double	timestep,
		Integrator *	result )

Initializes an Integrator

Parameters

gain	The gain to assign the integrator
timestep	The timestep to approximate the integrator
result	A return parameter, which becomes the integrator with the gain and timestep

Returns

result, which will be an integrator with a gain gain, and the timestep

PID()

double PID ( double input, Proportional * p, Integrator * i, Differentiator * d, double lower_lim, double upper_lim )

inline

Timesteps a PID Controller

Parameters

input	The input to the PID Controller
p	A pointer to the proportional term
i	A pointer to the integrator term
d	A pointer to the differentiator term
lower_lim	The lower saturation limit of the system
upper_lim	The upper saturation limit of the system

Returns

The output of the PID Controller given the input

Precondition

The input is the next sampled value of the input to all non-NULL Control Blocks

If p, i or d is NULL, then those NULL terms don't contribute

if p, i and d are all NULL, then the output is 0.0

Postcondition

i and d are updated with current/past calculated values

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