60 lines
2.1 KiB
C
60 lines
2.1 KiB
C
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/* Copyright (C) 2012 Kristian Lauszus, TKJ Electronics. All rights reserved.
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This software may be distributed and modified under the terms of the GNU
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General Public License version 2 (GPL2) as published by the Free Software
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Foundation and appearing in the file GPL2.TXT included in the packaging of
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this file. Please note that GPL2 Section 2[b] requires that all works based
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on this software must also be made publicly available under the terms of
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the GPL2 ("Copyleft").
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Contact information
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-------------------
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Kristian Lauszus, TKJ Electronics
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Web : http://www.tkjelectronics.com
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e-mail : kristianl@tkjelectronics.com
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*/
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#ifndef _Kalman_h_
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#define _Kalman_h_
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class Kalman {
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public:
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Kalman();
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// The angle should be in degrees and the rate should be in degrees per second and the delta time in seconds
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float getAngle(float newAngle, float newRate, float dt);
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void setAngle(float angle); // Used to set angle, this should be set as the starting angle
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float getRate(); // Return the unbiased rate
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/* These are used to tune the Kalman filter */
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void setQangle(float Q_angle);
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/**
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* setQbias(float Q_bias)
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* Default value (0.003f) is in Kalman.cpp.
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* Raise this to follow input more closely,
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* lower this to smooth result of kalman filter.
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*/
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void setQbias(float Q_bias);
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void setRmeasure(float R_measure);
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float getQangle();
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float getQbias();
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float getRmeasure();
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private:
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/* Kalman filter variables */
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float Q_angle; // Process noise variance for the accelerometer
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float Q_bias; // Process noise variance for the gyro bias
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float R_measure; // Measurement noise variance - this is actually the variance of the measurement noise
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float angle; // The angle calculated by the Kalman filter - part of the 2x1 state vector
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float bias; // The gyro bias calculated by the Kalman filter - part of the 2x1 state vector
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float rate; // Unbiased rate calculated from the rate and the calculated bias - you have to call getAngle to update the rate
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float P[2][2]; // Error covariance matrix - This is a 2x2 matrix
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};
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#endif
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