WPILibC++  2020.3.2
LinearDigitalFilter.h
1 /*----------------------------------------------------------------------------*/
2 /* Copyright (c) 2015-2019 FIRST. All Rights Reserved. */
3 /* Open Source Software - may be modified and shared by FRC teams. The code */
4 /* must be accompanied by the FIRST BSD license file in the root directory of */
5 /* the project. */
6 /*----------------------------------------------------------------------------*/
7 
8 #pragma once
9 
10 #include <initializer_list>
11 #include <memory>
12 #include <vector>
13 
14 #include <wpi/ArrayRef.h>
15 #include <wpi/circular_buffer.h>
16 #include <wpi/deprecated.h>
17 
18 #include "frc/filters/Filter.h"
19 
20 namespace frc {
21 
72 class LinearDigitalFilter : public Filter {
73  public:
81  WPI_DEPRECATED("Use LinearFilter class instead.")
83  wpi::ArrayRef<double> fbGains);
84 
92  WPI_DEPRECATED("Use LinearFilter class instead.")
93  LinearDigitalFilter(PIDSource& source, std::initializer_list<double> ffGains,
94  std::initializer_list<double> fbGains);
95 
103  WPI_DEPRECATED("Use LinearFilter class instead.")
104  LinearDigitalFilter(std::shared_ptr<PIDSource> source,
105  wpi::ArrayRef<double> ffGains,
106  wpi::ArrayRef<double> fbGains);
107 
115  WPI_DEPRECATED("Use LinearFilter class instead.")
116  LinearDigitalFilter(std::shared_ptr<PIDSource> source,
117  std::initializer_list<double> ffGains,
118  std::initializer_list<double> fbGains);
119 
121  LinearDigitalFilter& operator=(LinearDigitalFilter&&) = default;
122 
123  // Static methods to create commonly used filters
136  double timeConstant, double period);
137 
149  static LinearDigitalFilter HighPass(PIDSource& source, double timeConstant,
150  double period);
151 
162  static LinearDigitalFilter MovingAverage(PIDSource& source, int taps);
163 
175  static LinearDigitalFilter SinglePoleIIR(std::shared_ptr<PIDSource> source,
176  double timeConstant, double period);
177 
189  static LinearDigitalFilter HighPass(std::shared_ptr<PIDSource> source,
190  double timeConstant, double period);
191 
202  static LinearDigitalFilter MovingAverage(std::shared_ptr<PIDSource> source,
203  int taps);
204 
205  // Filter interface
206  double Get() const override;
207  void Reset() override;
208 
209  // PIDSource interface
215  double PIDGet() override;
216 
217  private:
220  std::vector<double> m_inputGains;
221  std::vector<double> m_outputGains;
222 };
223 
224 } // namespace frc
frc::PIDSource
PIDSource interface is a generic sensor source for the PID class.
Definition: PIDSource.h:20
frc::LinearDigitalFilter::LinearDigitalFilter
LinearDigitalFilter(PIDSource &source, wpi::ArrayRef< double > ffGains, wpi::ArrayRef< double > fbGains)
Create a linear FIR or IIR filter.
wpi::ArrayRef
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:42
frc::LinearDigitalFilter::Reset
void Reset() override
Reset the filter state.
frc::LinearDigitalFilter::SinglePoleIIR
static LinearDigitalFilter SinglePoleIIR(PIDSource &source, double timeConstant, double period)
Creates a one-pole IIR low-pass filter of the form: y[n] = (1 - gain) * x[n] + gain * y[n-1] where ...
frc::LinearDigitalFilter::PIDGet
double PIDGet() override
Calculates the next value of the filter.
wpi::circular_buffer< double >
frc
A class that enforces constraints on the differential drive kinematics.
Definition: SPIAccelerometerSim.h:16
frc::LinearDigitalFilter::HighPass
static LinearDigitalFilter HighPass(PIDSource &source, double timeConstant, double period)
Creates a first-order high-pass filter of the form: y[n] = gain * x[n] + (-gain) * x[n-1] + gain * y...
frc::LinearDigitalFilter::Get
double Get() const override
Returns the current filter estimate without also inserting new data as PIDGet() would do.
frc::Filter
Interface for filters.
Definition: Filter.h:21
frc::LinearDigitalFilter::MovingAverage
static LinearDigitalFilter MovingAverage(PIDSource &source, int taps)
Creates a K-tap FIR moving average filter of the form: y[n] = 1/k * (x[k] + x[k-1] + … + x[0])
frc::LinearDigitalFilter
This class implements a linear, digital filter.
Definition: LinearDigitalFilter.h:72