control_filters::LowPassFilter< T > Class Template Reference

A Low-pass filter class. More...

#include <low_pass_filter.hpp>

Inheritance diagram for control_filters::LowPassFilter< T >:

Collaboration diagram for control_filters::LowPassFilter< T >:

Public Member Functions
bool	configure () override
	Configure the LowPassFilter (access and process params).
bool	update (const T &data_in, T &data_out) override
	Applies one iteration of the IIR filter.
bool	update (const geometry_msgs::msg::WrenchStamped &data_in, geometry_msgs::msg::WrenchStamped &data_out)

Detailed Description

template<typename T>
class control_filters::LowPassFilter< T >

A Low-pass filter class.

This class implements a low-pass filter for various data types based on an Infinite Impulse Response Filter.

In particular, this class implements a simplified version of an IIR filter equation :

\(y(n) = b x(n-1) + a y(n-1)\)

where:

• \( x(n)\) is the input signal
• \( y(n)\) is the output signal (filtered)
• \( b \) is the feedforward filter coefficient
• \( a \) is the feedback filter coefficient

and the Low-Pass coefficient equation:

• \( a = e^{\frac{-1}{sf} \frac{2\pi df}{10^{\frac{di}{-10}}}} \)
• \( b = 1 - a \)

where:

• \( sf \) is the sampling frequency
• \( df \) is the damping frequency
• \( di \) is the damping intensity (amplitude)

Usage

The LowPassFilter class is meant to be instantiated as a filter in a controller but can also be used elsewhere. For manual instantiation, you should first call configure() (in non-realtime) and then call update() at every update step.

Member Function Documentation

update()

template<typename T >

bool control_filters::LowPassFilter< T >::update ( const T &  data_in, T &  data_out  )

override

Applies one iteration of the IIR filter.

Parameters

data_in	input to the filter
data_out	filtered output

Returns

false if filter is not configured, true otherwise

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

• control_toolbox/include/control_filters/low_pass_filter.hpp