mirror of
https://github.com/PX4/PX4-Autopilot.git
synced 2026-05-22 06:14:14 +08:00
Mathieu Bresciani
549fb0d5de
* ekf2: Add FirstOrderLpf and InnovationLpf classes for innovation lowpass filtering * ekf2: use InnovLpf filter class in preflight checks * ekf2: move selection of yaw test limit for pre-flight check in function * ekf2: Move pre-flight checks into separate function * ekf2: use static constexpr insetead of inline for sq (square) function * ekf2: Split pre-flight checks in separate functions Also use the same check for all the innovations: innov_lpf < test and innov < 2xtest * ekf2: Add optical flow pre-flight check * ekf2: Combine FirstOrderLpf and InnovationLpf in single class * ekf2: check vel_pos_innov when ev_pos is active as well * ekf2: transform InnovationLpf into a header only library and pass the spike limit during the update call to avoid storing it here * ekf2: Static and const cleanup - set spike_lim constants as static constexpr, set innovation - set checker helper functions as static - rename the mix of heading and yaw as heading to avoid confusion * ekf2: use ternary operator in selectHeadingTestLimit instead of if-else * ekf2: store intermediate redults in const bool flags. Those will be used for logging * ekf2: set variable const whenever possible * ekf2: create PreFlightChecker class that handle all the innovation pre-flight checks. Add simple unit testing Use bitmask instead of general flag to have more granularity * PreFlightChecker: use setter for the innovations to check instead of sending booleans in the update function This makes it more scalable as more checks will be added * ekf: Use booleans instead of bitmask for ekf preflt checks Rename "down" to "vert"
80 lines
2.9 KiB
C++
80 lines
2.9 KiB
C++
/****************************************************************************
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*
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* Copyright (c) 2019 PX4 Development Team. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name PX4 nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/**
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* First order "alpha" IIR digital filter with input saturation
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*/
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#include <mathlib/mathlib.h>
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class InnovationLpf final
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{
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public:
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InnovationLpf() = default;
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~InnovationLpf() = default;
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void reset(float val = 0.f) { _x = val; }
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/**
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* Update the filter with a new value and returns the filtered state
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* The new value is constained by the limit set in setSpikeLimit
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* @param val new input
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* @param alpha normalized weight of the new input
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* @param spike_limit the amplitude of the saturation at the input of the filter
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* @return filtered output
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*/
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float update(float val, float alpha, float spike_limit)
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{
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float val_constrained = math::constrain(val, -spike_limit, spike_limit);
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float beta = 1.f - alpha;
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_x = beta * _x + alpha * val_constrained;
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return _x;
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}
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/**
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* Helper function to compute alpha from dt and the inverse of tau
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* @param dt sampling time in seconds
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* @param tau_inv inverse of the time constant of the filter
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* @return alpha, the normalized weight of a new measurement
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*/
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static float computeAlphaFromDtAndTauInv(float dt, float tau_inv)
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{
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return dt * tau_inv;
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}
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private:
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float _x; ///< current state of the filter
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};
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