wbc::LowPassFilter Class Reference

#include <filter.hpp>

Public Member Functions
	LowPassFilter (double cutoff_freq, double sample_time)
const Eigen::VectorXd &	apply (const Eigen::VectorXd &new_value)
void	reset ()

Protected Attributes
double	alpha_
bool	initialized_
Eigen::VectorXd	y_

Detailed Description

First order (exponential) low-pass filter for vector-valued signals:

\[ y_k = \alpha x_k + (1 - \alpha) y_{k-1}, \qquad \alpha = \frac{\Delta t}{\Delta t + \frac{1}{2\pi f_c}} \]

The filter state is initialized with the first input sample, so there is no transient from zero.

Constructor & Destructor Documentation

LowPassFilter()

wbc::LowPassFilter::LowPassFilter	(	double	cutoff_freq,
		double	sample_time )

Parameters

cutoff_freq	Cutoff frequency \(f_c\) in Hz. Has to be > 0.
sample_time	Time \(\Delta t\) in seconds between two consecutive calls of apply(). Has to be > 0.

Member Function Documentation

apply()

const Eigen::VectorXd & wbc::LowPassFilter::apply

(

const Eigen::VectorXd &

new_value

)

Add a new sample and return the filtered signal

reset()

void wbc::LowPassFilter::reset ( )

inline

Re-initialize the filter state with the next input sample

Member Data Documentation

alpha_

double wbc::LowPassFilter::alpha_

protected

initialized_

bool wbc::LowPassFilter::initialized_

protected

y_

Eigen::VectorXd wbc::LowPassFilter::y_

protected

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The documentation for this class was generated from the following files:

• src/tools/filter.hpp
• src/tools/filter.cpp