1 /* 2 * Copyright (c) 2015, Freescale Semiconductor, Inc. 3 * Copyright 2016-2017 NXP 4 * All rights reserved. 5 * 6 * SPDX-License-Identifier: BSD-3-Clause 7 */ 8 9 /*! \file precisionAccelerometer.h 10 \brief Implements accelerometer calibration routines 11 */ 12 13 #ifndef PRECISIONACCELEROMETER_H 14 #define PRECISIONACCELEROMETER_H 15 16 /// calibration constants 17 #define ACCEL_CAL_AVERAGING_SECS 2 ///< calibration measurement averaging period (s) 18 #define MAX_ACCEL_CAL_ORIENTATIONS 12 ///< number of stored precision accelerometer measurements 19 20 /// accelerometer measurement buffer 21 typedef struct AccelBuffer 22 { 23 float fGsStored[MAX_ACCEL_CAL_ORIENTATIONS][3]; ///< uncalibrated accelerometer measurements (g) 24 float fSumGs[3]; ///< averaging sum for current storage location 25 int16_t iStoreCounter; ///< number of remaining iterations at FUSION_HZ to average measurement 26 int16_t iStoreLocation; ///< -1 for none, 0 to 11 for the 12 storage locations 27 int16_t iStoreFlags; ///< denotes which measurements are present 28 } AccelBuffer; 29 30 /// precision accelerometer calibration structure 31 typedef struct AccelCalibration 32 { 33 // start of elements stored in flash memory 34 float fV[3]; ///< offset vector (g) 35 float finvW[3][3]; ///< inverse gain matrix 36 float fR0[3][3]; ///< forward rotation matrix for measurement 0 37 // end of elements stored in flash memory 38 float fmatA[10][10]; ///< scratch 10x10 matrix used by calibration algorithms 39 float fmatB[10][10]; ///< scratch 10x10 matrix used by calibration algorithms 40 float fvecA[10]; ///< scratch 10x1 vector used by calibration algorithms 41 float fvecB[4]; ///< scratch 4x1 vector used by calibration algorithms 42 float fA[3][3]; ///< ellipsoid matrix A 43 float finvA[3][3]; ///< inverse of the ellipsoid matrix A 44 } AccelCalibration; 45 46 struct AccelSensor; // actual typedef is located in sensor_fusion_types.h 47 48 // function prototypes for functions in precisionAcclerometer.c 49 /// Initialize the accelerometer calibration functions 50 void fInitializeAccelCalibration( 51 struct AccelCalibration *pthisAccelCal, ///< Accelerometer calibration parameter structure 52 struct AccelBuffer *pthisAccelBuffer, ///< Buffer of measurements used as input to the accel calibration functions 53 volatile int8_t *AccelCalPacketOn ///< Used to coordinate calibration sample storage and communications 54 ); 55 /// Update the buffer used to store samples used for accelerometer calibration. 56 void fUpdateAccelBuffer( 57 struct AccelCalibration *pthisAccelCal, ///< Accelerometer calibration parameter structure 58 struct AccelBuffer *pthisAccelBuffer, ///< Buffer of measurements used as input to the accel calibration functions 59 struct AccelSensor* pthisAccel, ///< Pointer to the accelerometer input/state structure 60 volatile int8_t *AccelCalPacketOn ///< Used to coordinate calibration sample storage and communications 61 ); 62 /// function maps the accelerometer data fGs (g) onto precision calibrated and de-rotated data fGc (g), iGc (counts) 63 void fInvertAccelCal( 64 struct AccelSensor *pthisAccel, ///< Pointer to the accelerometer input/state structure 65 struct AccelCalibration *pthisAccelCal ///< Accelerometer calibration parameter structure 66 ); 67 /// function runs the precision accelerometer calibration 68 void fRunAccelCalibration( 69 struct AccelCalibration *pthisAccelCal, ///< Accelerometer calibration parameter structure 70 struct AccelBuffer *pthisAccelBuffer, ///< Buffer of measurements used as input to the accel calibration functions 71 struct AccelSensor* pthisAccel ///< Pointer to the accelerometer input/state structure 72 ); 73 /// calculate the 4 element calibration from the available measurements 74 void fComputeAccelCalibration4( 75 struct AccelBuffer *pthisAccelBuffer, ///< Buffer of measurements used as input to the accel calibration functions 76 struct AccelCalibration *pthisAccelCal, ///< Accelerometer calibration parameter structure 77 struct AccelSensor* pthisAccel ///< Pointer to the accelerometer input/state structure 78 ); 79 /// calculate the 7 element calibration from the available measurements 80 void fComputeAccelCalibration7( 81 struct AccelBuffer *pthisAccelBuffer, ///< Buffer of measurements used as input to the accel calibration functions 82 struct AccelCalibration *pthisAccelCal, ///< Accelerometer calibration parameter structure 83 struct AccelSensor* pthisAccel ///< Pointer to the accelerometer input/state structure 84 ); 85 /// calculate the 10 element calibration from the available measurements 86 void fComputeAccelCalibration10( 87 struct AccelBuffer *pthisAccelBuffer, ///< Buffer of measurements used as input to the accel calibration functions 88 struct AccelCalibration *pthisAccelCal, ///< Accelerometer calibration parameter structure 89 struct AccelSensor* pthisAccel ///< Pointer to the accelerometer input/state structure 90 ); 91 92 #endif // PRECISIONACCELEROMETER_H 93
