Chun Feng Huang / ATTITUDE_ESTIMATION_WIPV

Attitude estimation using IMU (3-DoF ver.)

Fork of ATTITUDE_ESTIMATION by LDSC_Robotics_TAs

ATTITUDE_ESTIMATION.cpp@8:3882cb4be9d3, 2016-12-27 (annotated)

Committer:
benson516
Date:
Tue Dec 27 11:28:49 2016 +0000
Revision:
8:3882cb4be9d3
Parent:
7:6fc812e342e6
Child:
9:84fad91d3587
Add the magnetic field estimation capability

Who changed what in which revision?

UserRevisionLine numberNew contents of line
benson516 0:8126c86bac2a 1 #include "ATTITUDE_ESTIMATION.h"
benson516 0:8126c86bac2a 2
benson516 6:c362ed165c39 3 //=====================LPF ====================//
benson516 6:c362ed165c39 4 LPF_vector::LPF_vector(size_t dimension, float samplingTime, float cutOff_freq_Hz_in)
benson516 6:c362ed165c39 5 {
benson516 6:c362ed165c39 6 n = dimension;
benson516 6:c362ed165c39 7 Ts = samplingTime;
benson516 6:c362ed165c39 8 cutOff_freq_Hz = cutOff_freq_Hz_in;
benson516 6:c362ed165c39 9 alpha_Ts = (2*3.1415926)*cutOff_freq_Hz*Ts;
benson516 6:c362ed165c39 10 One_alpha_Ts = 1.0 - alpha_Ts;
benson516 6:c362ed165c39 11
benson516 6:c362ed165c39 12 zeros.assign(n, 0.0);
benson516 6:c362ed165c39 13
benson516 6:c362ed165c39 14 output = zeros;
benson516 6:c362ed165c39 15
benson516 6:c362ed165c39 16 //
benson516 6:c362ed165c39 17 Flag_Init = false;
benson516 6:c362ed165c39 18 }
benson516 6:c362ed165c39 19
benson516 6:c362ed165c39 20 vector<float> LPF_vector::filter(const vector<float> &input)
benson516 6:c362ed165c39 21 {
benson516 6:c362ed165c39 22 // Initialization
benson516 6:c362ed165c39 23 if (!Flag_Init){
benson516 6:c362ed165c39 24 reset(input);
benson516 6:c362ed165c39 25 Flag_Init = true;
benson516 6:c362ed165c39 26 return output;
benson516 6:c362ed165c39 27 }
benson516 6:c362ed165c39 28
benson516 6:c362ed165c39 29 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 30 // output = One_alpha_Ts*output + alpha_Ts*input;
benson516 6:c362ed165c39 31 output[i] += alpha_Ts*(input[i] - output[i]);
benson516 6:c362ed165c39 32 }
benson516 6:c362ed165c39 33
benson516 6:c362ed165c39 34 return output;
benson516 6:c362ed165c39 35 }
benson516 6:c362ed165c39 36 void LPF_vector::reset(const vector<float> &input)
benson516 6:c362ed165c39 37 {
benson516 6:c362ed165c39 38 // output = (1.0 - alpha_Ts)*output + alpha_Ts*input;
benson516 6:c362ed165c39 39 output = input;
benson516 6:c362ed165c39 40 return;
benson516 6:c362ed165c39 41 }
benson516 6:c362ed165c39 42
benson516 6:c362ed165c39 43 //-------------------------------------------------------//
benson516 6:c362ed165c39 44 ATTITUDE::ATTITUDE(float alpha_in, float one_over_gamma_in, float Ts_in):
benson516 6:c362ed165c39 45 alpha(alpha_in),
benson516 6:c362ed165c39 46 one_over_gamma(one_over_gamma_in),
benson516 6:c362ed165c39 47 Ts(Ts_in),
benson516 8:3882cb4be9d3 48 lpfv_y_acce(3, Ts_in, 10.0), // Input filter for accelerometers
benson516 8:3882cb4be9d3 49 lpfv_y_mag(3, Ts_in, 200.0), // Input filter for magenetometers
benson516 8:3882cb4be9d3 50 lpfv_w(3, Ts_in, 200.0) // Input filter for gyroscope
benson516 0:8126c86bac2a 51 {
benson516 6:c362ed165c39 52 // Dimension
benson516 6:c362ed165c39 53 n = 3;
benson516 6:c362ed165c39 54 //
benson516 6:c362ed165c39 55 init_flag = 0; // Uninitialized
benson516 6:c362ed165c39 56
benson516 6:c362ed165c39 57 // Default: close the gyro-bias estimation
benson516 6:c362ed165c39 58 enable_biasEst = false;
benson516 8:3882cb4be9d3 59 enable_magEst = false;
benson516 6:c362ed165c39 60
benson516 6:c362ed165c39 61 // Unit transformation
benson516 6:c362ed165c39 62 pi = 3.1415926;
benson516 6:c362ed165c39 63 deg2rad = pi/180.0;
benson516 6:c362ed165c39 64 rad2deg = 180.0/pi;
benson516 7:6fc812e342e6 65 gravity = 9.81; // m/s^2
benson516 6:c362ed165c39 66
benson516 6:c362ed165c39 67 // The map from "real" coordinate to "here" coordinate
benson516 6:c362ed165c39 68 // eg. accMap_real2here = [3,-1,-2];
benson516 6:c362ed165c39 69 // means: real -> here
benson516 6:c362ed165c39 70 // 1 x z 3
benson516 6:c362ed165c39 71 // 2 y -x -1
benson516 6:c362ed165c39 72 // 3 z -y -2
benson516 6:c362ed165c39 73 // int accmap_temp[] = {3,-1,-2};
benson516 6:c362ed165c39 74 int accmap_temp[] = {-3,1,2}; // Reverse: The direction of accelerometer is defined based on the direction of the acceleration of the sensor, not the g-direction
benson516 6:c362ed165c39 75 // int accmap_temp[] = {1, 2, 3};
benson516 6:c362ed165c39 76 //
benson516 8:3882cb4be9d3 77 int magMap_temp[] = {3,-1, 2}; // real z-axis is in the reverse direction
benson516 6:c362ed165c39 78 int gyroMap_temp[] = {3,-1,-2};
benson516 6:c362ed165c39 79 accMap_real2here.assign(accmap_temp, accmap_temp+n);
benson516 8:3882cb4be9d3 80 magMap_real2here.assign(magMap_temp, magMap_temp+n);
benson516 6:c362ed165c39 81 gyroMap_real2here.assign(gyroMap_temp, gyroMap_temp+n);
benson516 6:c362ed165c39 82
benson516 6:c362ed165c39 83 // zeros
benson516 6:c362ed165c39 84 zeros.assign(n,0.0);
benson516 6:c362ed165c39 85 // unit_nz
benson516 6:c362ed165c39 86 unit_nx = zeros;
benson516 6:c362ed165c39 87 unit_ny = zeros;
benson516 6:c362ed165c39 88 unit_nz = zeros;
benson516 6:c362ed165c39 89 unit_nx[0] = -1; // negative x
benson516 6:c362ed165c39 90 unit_ny[1] = -1; // negative y
benson516 6:c362ed165c39 91 unit_nz[2] = -1; // negative z
benson516 6:c362ed165c39 92
benson516 6:c362ed165c39 93 // States
benson516 8:3882cb4be9d3 94 xg_est = unit_nx; // g is pointing downward
benson516 8:3882cb4be9d3 95 xm_est = Get_VectorScalarMultiply(unit_nz, -1.0); // m is pointing forward
benson516 6:c362ed165c39 96 gyroBias_est = zeros;
benson516 6:c362ed165c39 97 omega = zeros;
benson516 8:3882cb4be9d3 98 //
benson516 8:3882cb4be9d3 99 y_acce = zeros; // Accelerometer outputs
benson516 8:3882cb4be9d3 100 y_mag = zeros; // Magnetometer outputs
benson516 8:3882cb4be9d3 101 //
benson516 8:3882cb4be9d3 102 // w_cross_ys = zeros; // omega X ys
benson516 6:c362ed165c39 103 ys_cross_x_ys = zeros; // ys X (x_est - ys)
benson516 6:c362ed165c39 104
benson516 6:c362ed165c39 105 // Eular angles, in rad/s
benson516 6:c362ed165c39 106 pitch = 0.0;
benson516 6:c362ed165c39 107 roll = 0.0;
benson516 6:c362ed165c39 108 yaw = 0.0;
benson516 6:c362ed165c39 109
benson516 6:c362ed165c39 110
benson516 6:c362ed165c39 111 // Gain matrix
benson516 1:edc7ccfc5562 112 Set_L1_diag(alpha);
benson516 6:c362ed165c39 113
benson516 6:c362ed165c39 114 }
benson516 7:6fc812e342e6 115 // Public methods
benson516 8:3882cb4be9d3 116 void ATTITUDE::Vectors_to_EulerAngle(const vector<float> &vg_in, const vector<float> &vm_in){
benson516 7:6fc812e342e6 117 //
benson516 7:6fc812e342e6 118 // This function should be customized according to the definition of coordinate system
benson516 7:6fc812e342e6 119 //
benson516 6:c362ed165c39 120
benson516 7:6fc812e342e6 121 /*
benson516 7:6fc812e342e6 122 // Here we follow the definition in bicycle paper
benson516 7:6fc812e342e6 123 yaw = 0.0; // phi, yaw
benson516 8:3882cb4be9d3 124 roll = atan2(-vg_in[1],vg_in[0]); // theta, roll
benson516 8:3882cb4be9d3 125 pitch = atan2(cos(roll)*vg_in[2],vg_in[0]); // psi, pitch
benson516 7:6fc812e342e6 126 */
benson516 7:6fc812e342e6 127
benson516 7:6fc812e342e6 128 // Eular angle: 1-3-2, zs is pointing forwasd
benson516 8:3882cb4be9d3 129 // yaw = 0.0; // phi, yaw
benson516 8:3882cb4be9d3 130 pitch = atan2(-vg_in[2],-vg_in[0]); // psi, pitch
benson516 7:6fc812e342e6 131 if (abs(pitch) < 0.7854){ // pi/4
benson516 8:3882cb4be9d3 132 roll = atan2(cos(pitch)*vg_in[1],-vg_in[0]); // theta, roll
benson516 7:6fc812e342e6 133 }else{
benson516 7:6fc812e342e6 134 if (pitch >= 0.0)
benson516 8:3882cb4be9d3 135 roll = atan2(sin(pitch)*vg_in[1],-vg_in[2]); // theta, roll
benson516 7:6fc812e342e6 136 else
benson516 8:3882cb4be9d3 137 roll = atan2(-sin(pitch)*vg_in[1],vg_in[2]); // theta, roll
benson516 7:6fc812e342e6 138 }
benson516 7:6fc812e342e6 139
benson516 8:3882cb4be9d3 140 // Calculate the yaw angle
benson516 8:3882cb4be9d3 141 if (enable_magEst){
benson516 8:3882cb4be9d3 142 float num = vm_in[1]*cos(pitch);
benson516 8:3882cb4be9d3 143 float den = (vm_in[2]*cos(roll) - vm_in[1]*sin(pitch)*sin(roll));
benson516 8:3882cb4be9d3 144 yaw = atan2(num, den);
benson516 8:3882cb4be9d3 145 }else{
benson516 8:3882cb4be9d3 146 yaw = 0.0; // phi, yaw
benson516 8:3882cb4be9d3 147 }
benson516 7:6fc812e342e6 148
benson516 7:6fc812e342e6 149 }
benson516 7:6fc812e342e6 150 // Setting parameters
benson516 7:6fc812e342e6 151 // Set L1, the diagonal matrix
benson516 7:6fc812e342e6 152 void ATTITUDE::Set_L1_diag(float alpha_in) // set diagnal element of gain matrix
benson516 7:6fc812e342e6 153 {
benson516 7:6fc812e342e6 154 alpha = alpha_in;
benson516 7:6fc812e342e6 155 L1_diag.assign(n,alpha_in);
benson516 7:6fc812e342e6 156 }
benson516 7:6fc812e342e6 157 //
benson516 8:3882cb4be9d3 158 void ATTITUDE::Init(void) // Let x_est = ys
benson516 7:6fc812e342e6 159 {
benson516 8:3882cb4be9d3 160 // y_acce = y_in;
benson516 8:3882cb4be9d3 161 // Normolization(xg_est,y_in); // xg_est be set as normalized y_in
benson516 8:3882cb4be9d3 162 xg_est = y_acce;
benson516 8:3882cb4be9d3 163 xm_est = y_mag;
benson516 7:6fc812e342e6 164 ++init_flag;
benson516 7:6fc812e342e6 165 }
benson516 8:3882cb4be9d3 166 void ATTITUDE::iterateOnce(const vector<float> &y_acce_in, const vector<float> &omega_in) // Main alogorithm
benson516 7:6fc812e342e6 167 {
benson516 8:3882cb4be9d3 168 enable_magEst = false; // no magenetometers input
benson516 8:3882cb4be9d3 169 // Input mapping
benson516 8:3882cb4be9d3 170 InputMapping(y_acce, y_acce_in, accMap_real2here);
benson516 8:3882cb4be9d3 171 // InputMapping(y_mag, y_mag_in, magMap_real2here);
benson516 7:6fc812e342e6 172 InputMapping(omega, omega_in, gyroMap_real2here);
benson516 7:6fc812e342e6 173
benson516 7:6fc812e342e6 174 // Input filter
benson516 8:3882cb4be9d3 175 y_acce = lpfv_y_acce.filter(y_acce);
benson516 8:3882cb4be9d3 176 // y_mag = lpfv_y_mag.filter(y_mag);
benson516 7:6fc812e342e6 177 // omega = lpfv_w.filter(omega);
benson516 7:6fc812e342e6 178
benson516 7:6fc812e342e6 179 // gyro-bias estimation
benson516 7:6fc812e342e6 180 if (enable_biasEst){
benson516 8:3882cb4be9d3 181 omega = Get_VectorPlus(omega, gyroBias_est, true); // minus, omega - gyroBias_est
benson516 7:6fc812e342e6 182 }
benson516 7:6fc812e342e6 183
benson516 7:6fc812e342e6 184 //
benson516 7:6fc812e342e6 185 if(init_flag < 3){
benson516 8:3882cb4be9d3 186 Init();
benson516 7:6fc812e342e6 187 }
benson516 7:6fc812e342e6 188 else{
benson516 8:3882cb4be9d3 189 // Estimation kernel process
benson516 8:3882cb4be9d3 190 EstimationKernel(xg_est, y_acce, omega);
benson516 8:3882cb4be9d3 191 // EstimationKernel(xm_est, y_mag, omega);
benson516 7:6fc812e342e6 192
benson516 7:6fc812e342e6 193 // gyro-bias estimation
benson516 7:6fc812e342e6 194 if (enable_biasEst){
benson516 7:6fc812e342e6 195 updateGyroBiasEst();
benson516 7:6fc812e342e6 196 }
benson516 7:6fc812e342e6 197 }
benson516 7:6fc812e342e6 198 //
benson516 8:3882cb4be9d3 199 Vectors_to_EulerAngle(xg_est,xm_est);
benson516 8:3882cb4be9d3 200 }
benson516 8:3882cb4be9d3 201 void ATTITUDE::iterateOnce(const vector<float> &y_acce_in, const vector<float> &y_mag_in, const vector<float> &omega_in) // Main alogorithm
benson516 8:3882cb4be9d3 202 {
benson516 8:3882cb4be9d3 203 enable_magEst = true; // with magenetometers input
benson516 8:3882cb4be9d3 204 // Input mapping
benson516 8:3882cb4be9d3 205 InputMapping(y_acce, y_acce_in, accMap_real2here);
benson516 8:3882cb4be9d3 206 InputMapping(y_mag, y_mag_in, magMap_real2here);
benson516 8:3882cb4be9d3 207 InputMapping(omega, omega_in, gyroMap_real2here);
benson516 8:3882cb4be9d3 208
benson516 8:3882cb4be9d3 209 // Input filter
benson516 8:3882cb4be9d3 210 y_acce = lpfv_y_acce.filter(y_acce);
benson516 8:3882cb4be9d3 211 // y_mag = lpfv_y_mag.filter(y_mag);
benson516 8:3882cb4be9d3 212 // omega = lpfv_w.filter(omega);
benson516 8:3882cb4be9d3 213
benson516 8:3882cb4be9d3 214 // gyro-bias estimation
benson516 8:3882cb4be9d3 215 if (enable_biasEst){
benson516 8:3882cb4be9d3 216 omega = Get_VectorPlus(omega, gyroBias_est, true); // minus, omega - gyroBias_est
benson516 8:3882cb4be9d3 217 }
benson516 8:3882cb4be9d3 218
benson516 8:3882cb4be9d3 219 //
benson516 8:3882cb4be9d3 220 if(init_flag < 3){
benson516 8:3882cb4be9d3 221 Init();
benson516 8:3882cb4be9d3 222 }
benson516 8:3882cb4be9d3 223 else{
benson516 8:3882cb4be9d3 224 // Estimation kernel process
benson516 8:3882cb4be9d3 225 EstimationKernel(xg_est, y_acce, omega);
benson516 8:3882cb4be9d3 226 EstimationKernel(xm_est, y_mag, omega);
benson516 8:3882cb4be9d3 227
benson516 8:3882cb4be9d3 228 // gyro-bias estimation
benson516 8:3882cb4be9d3 229 if (enable_biasEst){
benson516 8:3882cb4be9d3 230 updateGyroBiasEst();
benson516 8:3882cb4be9d3 231 }
benson516 8:3882cb4be9d3 232 }
benson516 8:3882cb4be9d3 233 //
benson516 8:3882cb4be9d3 234 Vectors_to_EulerAngle(xg_est,xm_est);
benson516 7:6fc812e342e6 235 }
benson516 7:6fc812e342e6 236 // transform the x_est into "real" coordinate
benson516 7:6fc812e342e6 237 void ATTITUDE::getEstimation_realCoordinate(vector<float> &V_out){
benson516 8:3882cb4be9d3 238 OutputMapping(V_out,xg_est,accMap_real2here);
benson516 7:6fc812e342e6 239 }
benson516 7:6fc812e342e6 240 // Get Eular angles
benson516 7:6fc812e342e6 241 float ATTITUDE::pitch_deg(void){
benson516 7:6fc812e342e6 242 return (rad2deg*pitch);
benson516 7:6fc812e342e6 243 }
benson516 7:6fc812e342e6 244 float ATTITUDE::roll_deg(void){
benson516 7:6fc812e342e6 245 return (rad2deg*roll);
benson516 7:6fc812e342e6 246 }
benson516 7:6fc812e342e6 247 float ATTITUDE::yaw_deg(void){
benson516 7:6fc812e342e6 248 return (rad2deg*yaw);
benson516 7:6fc812e342e6 249 }
benson516 7:6fc812e342e6 250
benson516 7:6fc812e342e6 251 // Private methods
benson516 7:6fc812e342e6 252 ////////////////////////////////////
benson516 7:6fc812e342e6 253 // Input/output coordinate transformations within the different definitions between the "real" one and the "here" one
benson516 6:c362ed165c39 254 // real -> here
benson516 6:c362ed165c39 255 void ATTITUDE::InputMapping(vector<float> &v_hereDef, const vector<float> &v_realDef, const vector<int> &map_real2here){
benson516 6:c362ed165c39 256 // The map from "real" coordinate to "here" coordinate
benson516 6:c362ed165c39 257 // eg. accMap_real2here = [3,-1,-2];
benson516 6:c362ed165c39 258 // means: real -> here
benson516 6:c362ed165c39 259 // 1 x z 3
benson516 6:c362ed165c39 260 // 2 y -x -1
benson516 6:c362ed165c39 261 // 3 z -y -2
benson516 6:c362ed165c39 262 // vector<int> accMap_real2here = {3,-1,-2};
benson516 6:c362ed165c39 263 // vector<int> gyroMap_real2here = {3,-1,-2};
benson516 6:c362ed165c39 264
benson516 6:c362ed165c39 265 // Iterate through "real" coordinates
benson516 6:c362ed165c39 266 int idx_here = 1;
benson516 6:c362ed165c39 267 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 268 idx_here = map_real2here[i];
benson516 6:c362ed165c39 269 if (idx_here > 0){
benson516 6:c362ed165c39 270 v_hereDef[idx_here-1] = v_realDef[i];
benson516 6:c362ed165c39 271 }else{
benson516 6:c362ed165c39 272 v_hereDef[-idx_here-1] = -1*v_realDef[i];
benson516 6:c362ed165c39 273 }
benson516 6:c362ed165c39 274 }
benson516 0:8126c86bac2a 275 }
benson516 6:c362ed165c39 276 // here -> real
benson516 6:c362ed165c39 277 void ATTITUDE::OutputMapping(vector<float> &v_realDef, const vector<float> &v_hereDef, const vector<int> &map_real2here){
benson516 6:c362ed165c39 278 // This is the inverse mapping of the InputMapping
benson516 6:c362ed165c39 279
benson516 6:c362ed165c39 280 // The map from "real" coordinate to "here" coordinate
benson516 6:c362ed165c39 281 // eg. accMap_real2here = [3,-1,-2];
benson516 6:c362ed165c39 282 // means: real -> here
benson516 6:c362ed165c39 283 // 1 x z 3
benson516 6:c362ed165c39 284 // 2 y -x -1
benson516 6:c362ed165c39 285 // 3 z -y -2
benson516 6:c362ed165c39 286 // vector<int> accMap_real2here = {3,-1,-2};
benson516 6:c362ed165c39 287 // vector<int> gyroMap_real2here = {3,-1,-2};
benson516 6:c362ed165c39 288
benson516 6:c362ed165c39 289 // Iterate through "real" coordinates
benson516 6:c362ed165c39 290 int idx_here = 1;
benson516 6:c362ed165c39 291 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 292 idx_here = map_real2here[i];
benson516 6:c362ed165c39 293 if (idx_here > 0){
benson516 6:c362ed165c39 294 v_realDef[i] = v_hereDef[idx_here-1];
benson516 6:c362ed165c39 295 }else{
benson516 6:c362ed165c39 296 v_realDef[i] = -1*v_hereDef[-idx_here-1];
benson516 6:c362ed165c39 297 }
benson516 6:c362ed165c39 298 }
benson516 6:c362ed165c39 299 }
benson516 7:6fc812e342e6 300 // The kernel of the estimation process
benson516 7:6fc812e342e6 301 ////////////////////////////////////////
benson516 7:6fc812e342e6 302 void ATTITUDE::EstimationKernel(vector<float> &_x_est_, const vector<float> &_ys_, const vector<float> &_omega_){
benson516 7:6fc812e342e6 303 static vector<float> _w_cross_ys_;
benson516 7:6fc812e342e6 304 Get_CrossProduct3(_w_cross_ys_, _omega_, _ys_);
benson516 8:3882cb4be9d3 305 for(size_t i = 0; i < n; ++i){
benson516 7:6fc812e342e6 306 // x_est_plus[i] = x_est[i] + Ts*( L1_diag[i]*(ys[i] - x_est[i]) - w_cross_ys[i]);
benson516 7:6fc812e342e6 307 _x_est_[i] += Ts*( L1_diag[i]*(_ys_[i] - _x_est_[i]) - _w_cross_ys_[i]);
benson516 6:c362ed165c39 308 }
benson516 6:c362ed165c39 309
benson516 7:6fc812e342e6 310 }
benson516 7:6fc812e342e6 311 void ATTITUDE::updateGyroBiasEst(void){ // Update the gyro bias estimation
benson516 7:6fc812e342e6 312 if (one_over_gamma == 0.0){
benson516 7:6fc812e342e6 313 return;
benson516 7:6fc812e342e6 314 }
benson516 7:6fc812e342e6 315 //
benson516 8:3882cb4be9d3 316 Get_CrossProduct3(ys_cross_x_ys, y_acce, Get_VectorPlus(xg_est,y_acce,true));
benson516 7:6fc812e342e6 317 //
benson516 7:6fc812e342e6 318 gyroBias_est = Get_VectorPlus(gyroBias_est, Get_VectorScalarMultiply(ys_cross_x_ys, (one_over_gamma)), true);
benson516 7:6fc812e342e6 319 }
benson516 6:c362ed165c39 320
benson516 7:6fc812e342e6 321 //////////////////////////////////////// end The kernal of the estimation process
benson516 7:6fc812e342e6 322
benson516 7:6fc812e342e6 323 // Utilities
benson516 7:6fc812e342e6 324 // vector operation
benson516 6:c362ed165c39 325 void ATTITUDE::Get_CrossProduct3(vector<float> &v_c, const vector<float> &v_a, const vector<float> &v_b) // v_a X v_b
benson516 1:edc7ccfc5562 326 {
benson516 7:6fc812e342e6 327 // Check the size
benson516 7:6fc812e342e6 328 if (v_c.size() != n){
benson516 7:6fc812e342e6 329 v_c.resize(n);
benson516 7:6fc812e342e6 330 }
benson516 1:edc7ccfc5562 331 v_c[0] = (-v_a[2]*v_b[1]) + v_a[1]*v_b[2];
benson516 1:edc7ccfc5562 332 v_c[1] = v_a[2]*v_b[0] - v_a[0]*v_b[2];
benson516 6:c362ed165c39 333 v_c[2] = (-v_a[1]*v_b[0]) + v_a[0]*v_b[1];
benson516 1:edc7ccfc5562 334 }
benson516 6:c362ed165c39 335 vector<float> ATTITUDE::Get_VectorPlus(const vector<float> &v_a, const vector<float> &v_b, bool is_minus) // v_a + (or -) v_b
benson516 6:c362ed165c39 336 {
benson516 6:c362ed165c39 337 static vector<float> v_c(n);
benson516 6:c362ed165c39 338 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 339 if (is_minus){
benson516 6:c362ed165c39 340 v_c[i] = v_a[i] - v_b[i];
benson516 6:c362ed165c39 341 }else{
benson516 6:c362ed165c39 342 v_c[i] = v_a[i] + v_b[i];
benson516 6:c362ed165c39 343 }
benson516 6:c362ed165c39 344 }
benson516 6:c362ed165c39 345 return v_c;
benson516 6:c362ed165c39 346 }
benson516 6:c362ed165c39 347 vector<float> ATTITUDE::Get_VectorScalarMultiply(const vector<float> &v_a, float scale) // scale*v_a
benson516 6:c362ed165c39 348 {
benson516 6:c362ed165c39 349 static vector<float> v_c(n);
benson516 6:c362ed165c39 350 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 351 v_c[i] = scale*v_a[i];
benson516 6:c362ed165c39 352
benson516 6:c362ed165c39 353 }
benson516 6:c362ed165c39 354 return v_c;
benson516 6:c362ed165c39 355 }
benson516 6:c362ed165c39 356 float ATTITUDE::Get_Vector3Norm(const vector<float> &v_in)
benson516 1:edc7ccfc5562 357 {
benson516 1:edc7ccfc5562 358 float temp = 0.0;
benson516 6:c362ed165c39 359
benson516 6:c362ed165c39 360 for (size_t i = 0; i < n; ++i)
benson516 1:edc7ccfc5562 361 temp += v_in[i]*v_in[i];
benson516 6:c362ed165c39 362 return sqrt(temp); // <- Should check if this function is available (?)
benson516 1:edc7ccfc5562 363 }
benson516 6:c362ed165c39 364 void ATTITUDE::Normolization(vector<float> &V_out, const vector<float> &V_in){
benson516 6:c362ed165c39 365 float norm = Get_Vector3Norm(V_in);
benson516 6:c362ed165c39 366 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 367 V_out[i] = V_in[i]/norm;
benson516 6:c362ed165c39 368 }
benson516 6:c362ed165c39 369 }