Merge pull request #5 from aburt2/pr-add-calibration-parameters

Add calibration parameters for IMU data

puara_gestures.cpp

@@ -151,11 +151,28 @@ void PuaraGestures::updateOrientation() {
   orientation.update(0.01); // Weight of 0.01 towards previous orientation
 }
 
+void PuaraGestures::setCalibrationParameters(calibrationParameters calParams) {
+  // Save calibration parameters to class
+  // Magnetometer Cal
+  std::copy(std::begin(sx), std::end(sx), std::begin(calParams.sx));
+  std::copy(std::begin(sy), std::end(sy), std::begin(calParams.sy));
+  std::copy(std::begin(sz), std::end(sz), std::begin(calParams.sz));
+  std::copy(std::begin(h), std::end(h), std::begin(calParams.h));
+  // Accel Cal
+  std::copy(std::begin(accel_zerog), std::end(accel_zerog), std::begin(calParams.accel_zerog));
+  // Gyro Cal
+  std::copy(std::begin(gyro_zerorate), std::end(gyro_zerorate), std::begin(calParams.gyro_zerorate));
+}
+
 void PuaraGestures::setAccelerometerValues(float accelX, float accelY, float accelZ) {
-  orientation.setAccelerometerValues(accelX, accelY, accelZ);
-  this->accelX = accelX;
-  this->accelY = accelY;
-  this->accelZ = accelZ;
+  // Calibrate accelerometer
+  calibrateAccelerometer(accelX, accelY, accelZ);
+
+  // Save calibrate values for sensor fusion and puara gestures
+  orientation.setAccelerometerValues(accelCal[0], accelCal[1], accelCal[2]);
+  this->accelX = accelCal[0];
+  this->accelY = accelCal[1];
+  this->accelZ = accelCal[2];
 
   // Add accl data
   acclBuffers[0].push_back(accelX);
@@ -173,28 +190,59 @@ void PuaraGestures::setAccelerometerValues(float accelX, float accelY, float acc
 void PuaraGestures::setGyroscopeValues(float gyroX, float gyroY, float gyroZ) {   
   static long then = esp_timer_get_time();
   long now = esp_timer_get_time();
-  orientation.setGyroscopeDegreeValues(gyroX, gyroY, gyroZ, (now - then) * 0.000001);
+  // Calibrate Gyroscope
+  calibrateGyroscope(gyroX, gyroY, gyroZ);
+
+  orientation.setGyroscopeDegreeValues(gyroCal[0], gyroCal[1], gyroCal[2], (now - then) * 0.000001);
   then = now;     
-  gyroBuffers[0].push_back(gyroX);
-  gyroBuffers[1].push_back(gyroY);
-  gyroBuffers[2].push_back(gyroZ);
+  gyroBuffers[0].push_back(gyroCal[0]);
+  gyroBuffers[1].push_back(gyroCal[1]);
+  gyroBuffers[2].push_back(gyroCal[2]);
   if (gyroBuffers[0].size() > PuaraGestures::BUFFER_SIZE) {
     gyroBuffers[0].pop_front();
     gyroBuffers[1].pop_front();
     gyroBuffers[2].pop_front();
   }
-  this->gyroX = gyroX;
-  this->gyroY = gyroY;
-  this->gyroZ = gyroZ;
+  this->gyroX = gyroCal[0];
+  this->gyroY = gyroCal[1];
+  this->gyroZ = gyroCal[2];
 }
 
 void PuaraGestures::setMagnetometerValues(float magX, float magY, float magZ) {
-  orientation.setMagnetometerValues(magX, magY, magZ);
-  this->magX = magX;
-  this->magY = magY;
-  this->magZ = magZ;
+  // Calibrate magnetometer, sensor fusion code already assumes calibrate magnetometer, hence calibration occurs here
+  calibrateMagnetometer(magX, magY, magZ);
+
+  // Set magnetometer values for sensor fusion
+  orientation.setMagnetometerValues(magCal[0], magCal[1], magCal[2]);
+
+  // Save to puara gestures
+  this->magX = magCal[0];
+  this->magY = magCal[1];
+  this->magZ = magCal[2];
 }
 
+void PuaraGestures::calibrateMagnetometer(float magX, float magY, float magZ) {
+  // Calibrate magnetometer
+  magCal[0] = sx[0]*(magX-h[0]) + sx[1]*(magX-h[0]) + sx[2]*(magX-h[0]);
+  magCal[1] = sy[0]*(magY-h[1]) + sy[1]*(magY-h[1]) + sy[2]*(magY-h[1]);
+  magCal[2] = sz[0]*(magZ-h[2]) + sz[1]*(magZ-h[2]) + sz[2]*(magZ-h[2]);
+}
+
+void PuaraGestures::calibrateAccelerometer(float accelX, float accelY, float accelZ) {
+  // Calibrate accelerometer
+  accelCal[0] = accelX - accel_zerog[0];
+  accelCal[1] = accelY - accel_zerog[1];
+  accelCal[2] = accelZ - accel_zerog[2];
+}
+
+void PuaraGestures::calibrateGyroscope(float gyroX, float gyroY, float gyroZ) {
+  // Calibrate magnetometer
+  gyroCal[0] = gyroX - gyro_zerorate[0];
+  gyroCal[1] = gyroY - gyro_zerorate[1];
+  gyroCal[2] = gyroZ - gyro_zerorate[2];
+}
+
+
 // Simple leaky integrator implementation
 // Create a unsigned long global variable for time counter for each leak implementation (timer)
 float PuaraGestures::leakyIntegrator (float reading, float old_value, float leak, int frequency, unsigned long& timer) {

puara_gestures.h

@@ -15,6 +15,21 @@
 #include "esp_timer.h"
 #include "IMU_Sensor_Fusion/imu_orientation.h"
 
+// Calibration parameter input structure
+struct calibrationParameters {
+    // Accelerometer Parameters
+    float accel_zerog[3];
+
+    // Gyroscope Parameters
+    float gyro_zerorate[3];
+
+    // Magnetometer Parameters
+    float sx[3];
+    float sy[3];
+    float sz[3];
+    float h[3];
+};
+
 class PuaraGestures {
 
     private:
@@ -133,7 +148,28 @@ class PuaraGestures {
         // Orientation quaternion and euler values
         IMU_Orientation::Quaternion getOrientationQuaternion();
         IMU_Orientation::Euler getOrientationEuler();
-
+
+        // Calibration Methods
+        void calibrateMagnetometer(float magX, float magY, float magZ);
+        void calibrateAccelerometer(float accelX, float accelY, float accelZ);
+        void calibrateGyroscope(float gyroX, float gyroY, float gyroZ);
+        void setCalibrationParameters(calibrationParameters calParams);
+
+        // Magnetometer Calibration Variables
+        float sx[3] = {0.333, 0.333, 0.333};
+        float sy[3] = {0.333, 0.333, 0.333};
+        float sz[3] = {0.333, 0.333, 0.333};
+        float h[3] = {0,0,0};
+        float magCal[3];
+
+        // Accelerometer Calibration variables
+        float accel_zerog[3] = {0,0,0};
+        float accelCal[3];
+
+        /// Gyroscope Calibration variables
+        float gyro_zerorate[3] = {0,0,0};
+        float gyroCal[3];
+
         // touch array
         void updateTouchArray (int *discrete_touch, int touchSize);
         float touchAll;         // f, 0--1