SlewRate.hpp
2.96 KB
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/****************************************************************************
*
* Copyright (c) 2020 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file SlewRate.hpp
*
* Library limit the rate of change of a value with a maximum slew rate.
*
* @author Matthias Grob <maetugr@gmail.com>
*/
#pragma once
#include <mathlib/mathlib.h>
#include <matrix/math.hpp>
template<typename Type>
class SlewRate
{
public:
SlewRate() = default;
~SlewRate() = default;
/**
* Set maximum rate of change for the value
* @param slew_rate maximum rate of change
*/
void setSlewRate(const Type slew_rate) { _slew_rate = slew_rate; }
/**
* Set value ignoring slew rate for initialization purpose
* @param value new applied value
*/
void setForcedValue(const Type value) { _value = value; }
/**
* Update slewrate
* @param new_value desired new value
* @param deltatime time in seconds since last update
* @return actual value that complies with the slew rate
*/
Type update(const Type new_value, const float deltatime)
{
// Limit the rate of change of the value
const Type dvalue_desired = new_value - _value;
const Type dvalue_max = _slew_rate * deltatime;
const Type dvalue = math::constrain(dvalue_desired, -dvalue_max, dvalue_max);
_value += dvalue;
return _value;
}
protected:
Type _slew_rate{}; ///< maximum rate of change for the value
Type _value{}; ///< state to keep last value of the slew rate
};