Revision 1:4b0e8441f099, committed 2011-02-07

Comitter:

nimbusgb

Date:

Mon Feb 07 22:02:32 2011 +0000

Parent:

0:6a5296aa7dbf

Child:

2:202906c5fadd

Commit message:

added ability to adjust gyro errors for tuning purposes

Changed in this revision

--- a/IMUfilter.cpp	Sat Feb 05 18:57:55 2011 +0000
+++ b/IMUfilter.cpp	Mon Feb 07 22:02:32 2011 +0000
@@ -173,7 +173,7 @@
     double ASq_1, ASq_2, ASq_3, ASq_4;    
                               
     //Compute the quaternion conjugate.
-    ESq_1 = SEq_1;
+    ESq_1 =  SEq_1;
     ESq_2 = -SEq_2;
     ESq_3 = -SEq_3;
     ESq_4 = -SEq_4;
@@ -185,9 +185,9 @@
     ASq_4 = ESq_1 * AEq_4 + ESq_2 * AEq_3 - ESq_3 * AEq_2 + ESq_4 * AEq_1;
 
     //Compute the Euler angles from the quaternion.
-    phi = atan2(2 * ASq_3 * ASq_4 - 2 * ASq_1 * ASq_2, 2 * ASq_1 * ASq_1 + 2 * ASq_4 * ASq_4 - 1);
-    theta = asin(2 * ASq_2 * ASq_3 - 2 * ASq_1 * ASq_3);
-    psi = atan2(2 * ASq_2 * ASq_3 - 2 * ASq_1 * ASq_4, 2 * ASq_1 * ASq_1 + 2 * ASq_2 * ASq_2 - 1);
+    phi   = atan2(2 * ASq_3 * ASq_4 - 2 * ASq_1 * ASq_2, 2 * ASq_1 * ASq_1 + 2 * ASq_4 * ASq_4 - 1);
+    theta = asin (2 * ASq_2 * ASq_3 - 2 * ASq_1 * ASq_3);
+    psi   = atan2(2 * ASq_2 * ASq_3 - 2 * ASq_1 * ASq_4, 2 * ASq_1 * ASq_1 + 2 * ASq_2 * ASq_2 - 1);
 
 }
 
@@ -209,6 +209,17 @@
 
 }
 
+void IMUfilter::setGyroError(double gyroscopeMeasurementError)
+    {
+    gyroMeasError = gyroscopeMeasurementError;
+    reset();
+    }
+    
+double IMUfilter::getGyroError(void)
+    {
+    return gyroMeasError;
+    }
+    
 void IMUfilter::reset(void) {
 
     firstUpdate = 0;
@@ -224,5 +235,7 @@
     SEq_2 = 0;
     SEq_3 = 0;
     SEq_4 = 0;
-
+    
+    //Compute beta.
+    beta = sqrt(3.0 / 4.0) * (PI * (gyroMeasError / 180.0));
 }

--- a/IMUfilter.h	Sat Feb 05 18:57:55 2011 +0000
+++ b/IMUfilter.h	Mon Feb 07 22:02:32 2011 +0000
@@ -1,143 +1,156 @@
-/**
- * @author Aaron Berk
- *
- * @section LICENSE
- *
- * Copyright (c) 2010 ARM Limited
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- *
- * @section DESCRIPTION
- *
- * IMU orientation filter developed by Sebastian Madgwick.
- *
- * Find more details about his paper here:
- *
- * http://code.google.com/p/imumargalgorithm30042010sohm/
- */
-
-#ifndef IMU_FILTER_H
-#define IMU_FILTER_H
-
-/**
- * Includes
- */
-#include "mbed.h"
-
-/**
- * Defines
- */
-#define PI 3.1415926536
-
-/**
- * IMU orientation filter.
- */
-class IMUfilter {
-
-public:
-
-    /**
-     * Constructor.
-     *
-     * Initializes filter variables.
-     *
-     * @param rate The rate at which the filter should be updated.
-     * @param gyroscopeMeasurementError The error of the gyroscope in degrees
-     *  per second. This used to calculate a tuning constant for the filter.
-     *  Try changing this value if there are jittery readings, or they change
-     *  too much or too fast when rotating the IMU.
-     */
-    IMUfilter(double rate, double gyroscopeMeasurementError);
-
-    /**
-     * Update the filter variables.
-     *
-     * @param w_x X-axis gyroscope reading in rad/s.
-     * @param w_y Y-axis gyroscope reading in rad/s.
-     * @param w_z Z-axis gyroscope reading in rad/s.
-     * @param a_x X-axis accelerometer reading in m/s/s.
-     * @param a_y Y-axis accelerometer reading in m/s/s.
-     * @param a_z Z-axis accelerometer reading in m/s/s.
-     */
-    void updateFilter(double w_x, double w_y, double w_z,
-                      double a_x, double a_y, double a_z);
-
-    /**
-     * Compute the Euler angles based on the current filter data.
-     */
-    void computeEuler(void);
-
-    /**
-     * Get the current roll.
-     *
-     * @return The current roll angle in radians.
-     */
-    double getRoll(void);
-
-    /**
-     * Get the current pitch.
-     *
-     * @return The current pitch angle in radians.
-     */
-    double getPitch(void);
-
-    /**
-     * Get the current yaw.
-     *
-     * @return The current yaw angle in radians.
-     */
-    double getYaw(void);
-
-    /**
-     * Reset the filter.
-     */
-    void reset(void);
-
-private:
-
-    int firstUpdate;
-
-    //Quaternion orientation of earth frame relative to auxiliary frame.
-    double AEq_1;
-    double AEq_2;
-    double AEq_3;
-    double AEq_4;
-
-    //Estimated orientation quaternion elements with initial conditions.
-    double SEq_1;
-    double SEq_2;
-    double SEq_3;
-    double SEq_4;
-
-    //Sampling period
-    double deltat;
-
-    //Gyroscope measurement error (in degrees per second).
-    double gyroMeasError;
-
-    //Compute beta (filter tuning constant..
-    double beta;
-
-    double phi;
-    double theta;
-    double psi;
-
-};
-
-#endif /* IMU_FILTER_H */
+/**
+ * @author Aaron Berk
+ *
+ * @section LICENSE
+ *
+ * Copyright (c) 2010 ARM Limited
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @section DESCRIPTION
+ *
+ * IMU orientation filter developed by Sebastian Madgwick.
+ *
+ * Find more details about his paper here:
+ *
+ * http://code.google.com/p/imumargalgorithm30042010sohm/
+ */
+
+#ifndef IMU_FILTER_H
+#define IMU_FILTER_H
+
+/**
+ * Includes
+ */
+#include "mbed.h"
+
+/**
+ * Defines
+ */
+#define PI 3.1415926536
+
+/**
+ * IMU orientation filter.
+ */
+class IMUfilter {
+
+public:
+
+    /**
+     * Constructor.
+     *
+     * Initializes filter variables.
+     *
+     * @param rate The rate at which the filter should be updated.
+     * @param gyroscopeMeasurementError The error of the gyroscope in degrees
+     *  per second. This used to calculate a tuning constant for the filter.
+     *  Try changing this value if there are jittery readings, or they change
+     *  too much or too fast when rotating the IMU.
+     */
+    IMUfilter(double rate, double gyroscopeMeasurementError);
+
+    /**
+     * Update the filter variables.
+     *
+     * @param w_x X-axis gyroscope reading in rad/s.
+     * @param w_y Y-axis gyroscope reading in rad/s.
+     * @param w_z Z-axis gyroscope reading in rad/s.
+     * @param a_x X-axis accelerometer reading in m/s/s.
+     * @param a_y Y-axis accelerometer reading in m/s/s.
+     * @param a_z Z-axis accelerometer reading in m/s/s.
+     */
+    void updateFilter(double w_x, double w_y, double w_z,
+                      double a_x, double a_y, double a_z);
+
+    /**
+     * Compute the Euler angles based on the current filter data.
+     */
+    void computeEuler(void);
+
+    /**
+     * Get the current roll.
+     *
+     * @return The current roll angle in radians.
+     */
+    double getRoll(void);
+
+    /**
+     * Get the current pitch.
+     *
+     * @return The current pitch angle in radians.
+     */
+    double getPitch(void);
+
+    /**
+     * Get the current yaw.
+     *
+     * @return The current yaw angle in radians.
+     */
+    double getYaw(void);
+    
+    /**
+     * Get the current Gyro error rate.
+     *
+     * @return The Gyro error rate setting.
+     */
+    double getGyroError(void);
+    
+    /**
+     * Set the Gyro error rate. 
+     * The filter resets during calling this routine.
+     */
+    void setGyroError(double gyroscopeMeasurementError);
+
+    /**
+     * Reset the filter.
+     */
+    void reset(void);
+
+private:
+
+    int firstUpdate;
+
+    //Quaternion orientation of earth frame relative to auxiliary frame.
+    double AEq_1;
+    double AEq_2;
+    double AEq_3;
+    double AEq_4;
+
+    //Estimated orientation quaternion elements with initial conditions.
+    double SEq_1;
+    double SEq_2;
+    double SEq_3;
+    double SEq_4;
+
+    //Sampling period
+    double deltat;
+
+    //Gyroscope measurement error (in degrees per second).
+    double gyroMeasError;
+
+    //Compute beta (filter tuning constant..
+    double beta;
+
+    double phi;
+    double theta;
+    double psi;
+
+};
+
+#endif /* IMU_FILTER_H */