IMU filter
Fork of IMUfilter by
IMUfilter.h@1:8a920397b510, 2010-09-06 (annotated)
- Committer:
- aberk
- Date:
- Mon Sep 06 14:18:33 2010 +0000
- Revision:
- 1:8a920397b510
- Parent:
- 0:976ab2e4e4bd
- Child:
- 2:fae851819c43
Added method to reset the filter.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
aberk | 0:976ab2e4e4bd | 1 | /** |
aberk | 0:976ab2e4e4bd | 2 | * @author Aaron Berk |
aberk | 0:976ab2e4e4bd | 3 | * |
aberk | 0:976ab2e4e4bd | 4 | * @section LICENSE |
aberk | 0:976ab2e4e4bd | 5 | * |
aberk | 0:976ab2e4e4bd | 6 | * Copyright (c) 2010 ARM Limited |
aberk | 0:976ab2e4e4bd | 7 | * |
aberk | 0:976ab2e4e4bd | 8 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
aberk | 0:976ab2e4e4bd | 9 | * of this software and associated documentation files (the "Software"), to deal |
aberk | 0:976ab2e4e4bd | 10 | * in the Software without restriction, including without limitation the rights |
aberk | 0:976ab2e4e4bd | 11 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
aberk | 0:976ab2e4e4bd | 12 | * copies of the Software, and to permit persons to whom the Software is |
aberk | 0:976ab2e4e4bd | 13 | * furnished to do so, subject to the following conditions: |
aberk | 0:976ab2e4e4bd | 14 | * |
aberk | 0:976ab2e4e4bd | 15 | * The above copyright notice and this permission notice shall be included in |
aberk | 0:976ab2e4e4bd | 16 | * all copies or substantial portions of the Software. |
aberk | 0:976ab2e4e4bd | 17 | * |
aberk | 0:976ab2e4e4bd | 18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
aberk | 0:976ab2e4e4bd | 19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
aberk | 0:976ab2e4e4bd | 20 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
aberk | 0:976ab2e4e4bd | 21 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
aberk | 0:976ab2e4e4bd | 22 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
aberk | 0:976ab2e4e4bd | 23 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
aberk | 0:976ab2e4e4bd | 24 | * THE SOFTWARE. |
aberk | 0:976ab2e4e4bd | 25 | * |
aberk | 0:976ab2e4e4bd | 26 | * @section DESCRIPTION |
aberk | 0:976ab2e4e4bd | 27 | * |
aberk | 0:976ab2e4e4bd | 28 | * IMU orientation filter developed by Sebastian Madgwick. |
aberk | 0:976ab2e4e4bd | 29 | * |
aberk | 0:976ab2e4e4bd | 30 | * Find more details about his paper here: |
aberk | 0:976ab2e4e4bd | 31 | * |
aberk | 0:976ab2e4e4bd | 32 | * http://code.google.com/p/imumargalgorithm30042010sohm/ |
aberk | 0:976ab2e4e4bd | 33 | */ |
aberk | 0:976ab2e4e4bd | 34 | |
aberk | 0:976ab2e4e4bd | 35 | #ifndef IMU_FILTER_H |
aberk | 0:976ab2e4e4bd | 36 | #define IMU_FILTER_H |
aberk | 0:976ab2e4e4bd | 37 | |
aberk | 0:976ab2e4e4bd | 38 | /** |
aberk | 0:976ab2e4e4bd | 39 | * Includes |
aberk | 0:976ab2e4e4bd | 40 | */ |
aberk | 0:976ab2e4e4bd | 41 | #include "mbed.h" |
aberk | 0:976ab2e4e4bd | 42 | |
aberk | 0:976ab2e4e4bd | 43 | /** |
aberk | 0:976ab2e4e4bd | 44 | * Defines |
aberk | 0:976ab2e4e4bd | 45 | */ |
aberk | 0:976ab2e4e4bd | 46 | #define PI 3.1415926536 |
aberk | 0:976ab2e4e4bd | 47 | |
aberk | 0:976ab2e4e4bd | 48 | /** |
aberk | 0:976ab2e4e4bd | 49 | * IMU orientation filter. |
aberk | 0:976ab2e4e4bd | 50 | */ |
aberk | 0:976ab2e4e4bd | 51 | class IMUfilter { |
aberk | 0:976ab2e4e4bd | 52 | |
aberk | 0:976ab2e4e4bd | 53 | public: |
aberk | 0:976ab2e4e4bd | 54 | |
aberk | 0:976ab2e4e4bd | 55 | /** |
aberk | 0:976ab2e4e4bd | 56 | * Constructor. |
aberk | 0:976ab2e4e4bd | 57 | * |
aberk | 0:976ab2e4e4bd | 58 | * Initializes filter variables. |
aberk | 0:976ab2e4e4bd | 59 | * |
aberk | 0:976ab2e4e4bd | 60 | * @param rate The rate at which the filter should be updated. |
aberk | 0:976ab2e4e4bd | 61 | * @param gyroscopeMeasurementError The error of the gyroscope in degrees |
aberk | 0:976ab2e4e4bd | 62 | * per second. This used to calculate a tuning constant for the filter. |
aberk | 0:976ab2e4e4bd | 63 | * Try changing this value if there are jittery readings, or they change |
aberk | 0:976ab2e4e4bd | 64 | * too much or too fast when rotating the IMU. |
aberk | 0:976ab2e4e4bd | 65 | */ |
aberk | 0:976ab2e4e4bd | 66 | IMUfilter(double rate, double gyroscopeMeasurementError); |
aberk | 0:976ab2e4e4bd | 67 | |
aberk | 0:976ab2e4e4bd | 68 | /** |
aberk | 0:976ab2e4e4bd | 69 | * Update the filter variables. |
aberk | 0:976ab2e4e4bd | 70 | * |
aberk | 0:976ab2e4e4bd | 71 | * @param w_x X-axis gyroscope reading in rad/s. |
aberk | 0:976ab2e4e4bd | 72 | * @param w_y Y-axis gyroscope reading in rad/s. |
aberk | 0:976ab2e4e4bd | 73 | * @param w_z Z-axis gyroscope reading in rad/s. |
aberk | 0:976ab2e4e4bd | 74 | * @param a_x X-axis accelerometer reading in m/s/s. |
aberk | 0:976ab2e4e4bd | 75 | * @param a_y Y-axis accelerometer reading in m/s/s. |
aberk | 0:976ab2e4e4bd | 76 | * @param a_z Z-axis accelerometer reading in m/s/s. |
aberk | 0:976ab2e4e4bd | 77 | */ |
aberk | 0:976ab2e4e4bd | 78 | void updateFilter(double w_x, double w_y, double w_z, |
aberk | 0:976ab2e4e4bd | 79 | double a_x, double a_y, double a_z); |
aberk | 0:976ab2e4e4bd | 80 | |
aberk | 0:976ab2e4e4bd | 81 | /** |
aberk | 0:976ab2e4e4bd | 82 | * Compute the Euler angles based on the current filter data. |
aberk | 0:976ab2e4e4bd | 83 | */ |
aberk | 0:976ab2e4e4bd | 84 | void computeEuler(void); |
aberk | 0:976ab2e4e4bd | 85 | |
aberk | 0:976ab2e4e4bd | 86 | /** |
aberk | 0:976ab2e4e4bd | 87 | * Get the current roll. |
aberk | 0:976ab2e4e4bd | 88 | * |
aberk | 0:976ab2e4e4bd | 89 | * @return The current roll angle in radians. |
aberk | 0:976ab2e4e4bd | 90 | */ |
aberk | 0:976ab2e4e4bd | 91 | double getRoll(void); |
aberk | 0:976ab2e4e4bd | 92 | |
aberk | 0:976ab2e4e4bd | 93 | /** |
aberk | 0:976ab2e4e4bd | 94 | * Get the current pitch. |
aberk | 0:976ab2e4e4bd | 95 | * |
aberk | 0:976ab2e4e4bd | 96 | * @return The current pitch angle in radians. |
aberk | 0:976ab2e4e4bd | 97 | */ |
aberk | 0:976ab2e4e4bd | 98 | double getPitch(void); |
aberk | 0:976ab2e4e4bd | 99 | |
aberk | 0:976ab2e4e4bd | 100 | /** |
aberk | 0:976ab2e4e4bd | 101 | * Get the current yaw. |
aberk | 0:976ab2e4e4bd | 102 | * |
aberk | 0:976ab2e4e4bd | 103 | * @return The current yaw angle in radians. |
aberk | 0:976ab2e4e4bd | 104 | */ |
aberk | 0:976ab2e4e4bd | 105 | double getYaw(void); |
aberk | 0:976ab2e4e4bd | 106 | |
aberk | 1:8a920397b510 | 107 | /** |
aberk | 1:8a920397b510 | 108 | * Reset the filter. |
aberk | 1:8a920397b510 | 109 | */ |
aberk | 1:8a920397b510 | 110 | void reset(void); |
aberk | 1:8a920397b510 | 111 | |
aberk | 0:976ab2e4e4bd | 112 | private: |
aberk | 0:976ab2e4e4bd | 113 | |
aberk | 0:976ab2e4e4bd | 114 | int firstUpdate; |
aberk | 0:976ab2e4e4bd | 115 | |
aberk | 0:976ab2e4e4bd | 116 | //Quaternion orientation of earth frame relative to auxiliary frame. |
aberk | 0:976ab2e4e4bd | 117 | double AEq_1; |
aberk | 0:976ab2e4e4bd | 118 | double AEq_2; |
aberk | 0:976ab2e4e4bd | 119 | double AEq_3; |
aberk | 0:976ab2e4e4bd | 120 | double AEq_4; |
aberk | 0:976ab2e4e4bd | 121 | |
aberk | 0:976ab2e4e4bd | 122 | //Estimated orientation quaternion elements with initial conditions. |
aberk | 0:976ab2e4e4bd | 123 | double SEq_1; |
aberk | 0:976ab2e4e4bd | 124 | double SEq_2; |
aberk | 0:976ab2e4e4bd | 125 | double SEq_3; |
aberk | 0:976ab2e4e4bd | 126 | double SEq_4; |
aberk | 0:976ab2e4e4bd | 127 | |
aberk | 0:976ab2e4e4bd | 128 | //Sampling period |
aberk | 0:976ab2e4e4bd | 129 | double deltat; |
aberk | 0:976ab2e4e4bd | 130 | |
aberk | 0:976ab2e4e4bd | 131 | //Gyroscope measurement error (in degrees per second). |
aberk | 0:976ab2e4e4bd | 132 | double gyroMeasError; |
aberk | 0:976ab2e4e4bd | 133 | |
aberk | 0:976ab2e4e4bd | 134 | //Compute beta (filter tuning constant.. |
aberk | 0:976ab2e4e4bd | 135 | double beta; |
aberk | 0:976ab2e4e4bd | 136 | |
aberk | 0:976ab2e4e4bd | 137 | double phi; |
aberk | 0:976ab2e4e4bd | 138 | double theta; |
aberk | 0:976ab2e4e4bd | 139 | double psi; |
aberk | 0:976ab2e4e4bd | 140 | |
aberk | 0:976ab2e4e4bd | 141 | }; |
aberk | 0:976ab2e4e4bd | 142 | |
aberk | 0:976ab2e4e4bd | 143 | #endif /* IMU_FILTER_H */ |