BlockDerivative.cpp

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/**
 * @file blocks.cpp
 *
 * Controller library code
 */

#include <math.h>
#include <float.h>

#include "blocks.hpp"

namespace control
{

float BlockDerivative::update(float input)
{
    float output;

    if (_initialized) {
        output = _lowPass.update((input - getU()) / getDt());

    } else {
        // if this is the first call to update
        // we have no valid derivative
        // and so we use the assumption the
        // input value is not changing much,
        // which is the best we can do here.
        _lowPass.update(0.0f);
        output = 0.0f;
        _initialized = true;
    }

    setU(input);
    return output;
}

} // namespace control