Chun Feng Huang / ATTITUDE_ESTIMATION_WIPV

Attitude estimation using IMU (3-DoF ver.)

Fork of ATTITUDE_ESTIMATION by LDSC_Robotics_TAs

ATTITUDE_ESTIMATION.cpp@9:84fad91d3587, 2016-12-28 (annotated)

Committer:
benson516
Date:
Wed Dec 28 16:53:58 2016 +0000
Revision:
9:84fad91d3587
Parent:
8:3882cb4be9d3
Child:
10:166006e89252
Remove the one-over-gamma from constructor's argument list

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 9:84fad91d3587 44 ATTITUDE::ATTITUDE(float alpha_in, float Ts_in):
benson516 6:c362ed165c39 45 alpha(alpha_in),
benson516 6:c362ed165c39 46 Ts(Ts_in),
benson516 8:3882cb4be9d3 47 lpfv_y_acce(3, Ts_in, 10.0), // Input filter for accelerometers
benson516 8:3882cb4be9d3 48 lpfv_y_mag(3, Ts_in, 200.0), // Input filter for magenetometers
benson516 8:3882cb4be9d3 49 lpfv_w(3, Ts_in, 200.0) // Input filter for gyroscope
benson516 0:8126c86bac2a 50 {
benson516 6:c362ed165c39 51 // Dimension
benson516 6:c362ed165c39 52 n = 3;
benson516 6:c362ed165c39 53 //
benson516 6:c362ed165c39 54 init_flag = 0; // Uninitialized
benson516 6:c362ed165c39 55
benson516 6:c362ed165c39 56 // Default: close the gyro-bias estimation
benson516 6:c362ed165c39 57 enable_biasEst = false;
benson516 9:84fad91d3587 58 one_over_gamma = 0.0;
benson516 9:84fad91d3587 59 // Default: close the estimation for magenetic field
benson516 8:3882cb4be9d3 60 enable_magEst = false;
benson516 6:c362ed165c39 61
benson516 6:c362ed165c39 62 // Unit transformation
benson516 6:c362ed165c39 63 pi = 3.1415926;
benson516 6:c362ed165c39 64 deg2rad = pi/180.0;
benson516 6:c362ed165c39 65 rad2deg = 180.0/pi;
benson516 7:6fc812e342e6 66 gravity = 9.81; // m/s^2
benson516 6:c362ed165c39 67
benson516 6:c362ed165c39 68 // The map from "real" coordinate to "here" coordinate
benson516 6:c362ed165c39 69 // eg. accMap_real2here = [3,-1,-2];
benson516 6:c362ed165c39 70 // means: real -> here
benson516 6:c362ed165c39 71 // 1 x z 3
benson516 6:c362ed165c39 72 // 2 y -x -1
benson516 6:c362ed165c39 73 // 3 z -y -2
benson516 6:c362ed165c39 74 // int accmap_temp[] = {3,-1,-2};
benson516 6:c362ed165c39 75 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 76 // int accmap_temp[] = {1, 2, 3};
benson516 6:c362ed165c39 77 //
benson516 8:3882cb4be9d3 78 int magMap_temp[] = {3,-1, 2}; // real z-axis is in the reverse direction
benson516 6:c362ed165c39 79 int gyroMap_temp[] = {3,-1,-2};
benson516 6:c362ed165c39 80 accMap_real2here.assign(accmap_temp, accmap_temp+n);
benson516 8:3882cb4be9d3 81 magMap_real2here.assign(magMap_temp, magMap_temp+n);
benson516 6:c362ed165c39 82 gyroMap_real2here.assign(gyroMap_temp, gyroMap_temp+n);
benson516 6:c362ed165c39 83
benson516 6:c362ed165c39 84 // zeros
benson516 6:c362ed165c39 85 zeros.assign(n,0.0);
benson516 6:c362ed165c39 86 // unit_nz
benson516 6:c362ed165c39 87 unit_nx = zeros;
benson516 6:c362ed165c39 88 unit_ny = zeros;
benson516 6:c362ed165c39 89 unit_nz = zeros;
benson516 6:c362ed165c39 90 unit_nx[0] = -1; // negative x
benson516 6:c362ed165c39 91 unit_ny[1] = -1; // negative y
benson516 6:c362ed165c39 92 unit_nz[2] = -1; // negative z
benson516 6:c362ed165c39 93
benson516 6:c362ed165c39 94 // States
benson516 8:3882cb4be9d3 95 xg_est = unit_nx; // g is pointing downward
benson516 8:3882cb4be9d3 96 xm_est = Get_VectorScalarMultiply(unit_nz, -1.0); // m is pointing forward
benson516 6:c362ed165c39 97 gyroBias_est = zeros;
benson516 6:c362ed165c39 98 omega = zeros;
benson516 8:3882cb4be9d3 99 //
benson516 8:3882cb4be9d3 100 y_acce = zeros; // Accelerometer outputs
benson516 8:3882cb4be9d3 101 y_mag = zeros; // Magnetometer outputs
benson516 8:3882cb4be9d3 102 //
benson516 8:3882cb4be9d3 103 // w_cross_ys = zeros; // omega X ys
benson516 6:c362ed165c39 104 ys_cross_x_ys = zeros; // ys X (x_est - ys)
benson516 6:c362ed165c39 105
benson516 6:c362ed165c39 106 // Eular angles, in rad/s
benson516 6:c362ed165c39 107 pitch = 0.0;
benson516 6:c362ed165c39 108 roll = 0.0;
benson516 6:c362ed165c39 109 yaw = 0.0;
benson516 6:c362ed165c39 110
benson516 6:c362ed165c39 111
benson516 6:c362ed165c39 112 // Gain matrix
benson516 1:edc7ccfc5562 113 Set_L1_diag(alpha);
benson516 6:c362ed165c39 114
benson516 6:c362ed165c39 115 }
benson516 7:6fc812e342e6 116 // Public methods
benson516 8:3882cb4be9d3 117 void ATTITUDE::Vectors_to_EulerAngle(const vector<float> &vg_in, const vector<float> &vm_in){
benson516 7:6fc812e342e6 118 //
benson516 7:6fc812e342e6 119 // This function should be customized according to the definition of coordinate system
benson516 7:6fc812e342e6 120 //
benson516 6:c362ed165c39 121
benson516 7:6fc812e342e6 122 /*
benson516 7:6fc812e342e6 123 // Here we follow the definition in bicycle paper
benson516 7:6fc812e342e6 124 yaw = 0.0; // phi, yaw
benson516 8:3882cb4be9d3 125 roll = atan2(-vg_in[1],vg_in[0]); // theta, roll
benson516 8:3882cb4be9d3 126 pitch = atan2(cos(roll)*vg_in[2],vg_in[0]); // psi, pitch
benson516 7:6fc812e342e6 127 */
benson516 7:6fc812e342e6 128
benson516 9:84fad91d3587 129 // Eular angle: 1-3-2, zs is pointing forward
benson516 8:3882cb4be9d3 130 // yaw = 0.0; // phi, yaw
benson516 8:3882cb4be9d3 131 pitch = atan2(-vg_in[2],-vg_in[0]); // psi, pitch
benson516 7:6fc812e342e6 132 if (abs(pitch) < 0.7854){ // pi/4
benson516 8:3882cb4be9d3 133 roll = atan2(cos(pitch)*vg_in[1],-vg_in[0]); // theta, roll
benson516 7:6fc812e342e6 134 }else{
benson516 7:6fc812e342e6 135 if (pitch >= 0.0)
benson516 8:3882cb4be9d3 136 roll = atan2(sin(pitch)*vg_in[1],-vg_in[2]); // theta, roll
benson516 7:6fc812e342e6 137 else
benson516 8:3882cb4be9d3 138 roll = atan2(-sin(pitch)*vg_in[1],vg_in[2]); // theta, roll
benson516 7:6fc812e342e6 139 }
benson516 7:6fc812e342e6 140
benson516 8:3882cb4be9d3 141 // Calculate the yaw angle
benson516 8:3882cb4be9d3 142 if (enable_magEst){
benson516 8:3882cb4be9d3 143 float num = vm_in[1]*cos(pitch);
benson516 8:3882cb4be9d3 144 float den = (vm_in[2]*cos(roll) - vm_in[1]*sin(pitch)*sin(roll));
benson516 8:3882cb4be9d3 145 yaw = atan2(num, den);
benson516 8:3882cb4be9d3 146 }else{
benson516 8:3882cb4be9d3 147 yaw = 0.0; // phi, yaw
benson516 8:3882cb4be9d3 148 }
benson516 7:6fc812e342e6 149
benson516 7:6fc812e342e6 150 }
benson516 7:6fc812e342e6 151 // Setting parameters
benson516 7:6fc812e342e6 152 // Set L1, the diagonal matrix
benson516 7:6fc812e342e6 153 void ATTITUDE::Set_L1_diag(float alpha_in) // set diagnal element of gain matrix
benson516 7:6fc812e342e6 154 {
benson516 7:6fc812e342e6 155 alpha = alpha_in;
benson516 7:6fc812e342e6 156 L1_diag.assign(n,alpha_in);
benson516 7:6fc812e342e6 157 }
benson516 9:84fad91d3587 158 void ATTITUDE::enable_gyroBiasEst(float gamma_in){ // Enable the gyro-bias estimation
benson516 9:84fad91d3587 159 enable_biasEst = true;
benson516 9:84fad91d3587 160 one_over_gamma = 1/gamma_in;
benson516 9:84fad91d3587 161 }
benson516 7:6fc812e342e6 162 //
benson516 8:3882cb4be9d3 163 void ATTITUDE::Init(void) // Let x_est = ys
benson516 7:6fc812e342e6 164 {
benson516 8:3882cb4be9d3 165 // y_acce = y_in;
benson516 8:3882cb4be9d3 166 // Normolization(xg_est,y_in); // xg_est be set as normalized y_in
benson516 8:3882cb4be9d3 167 xg_est = y_acce;
benson516 8:3882cb4be9d3 168 xm_est = y_mag;
benson516 7:6fc812e342e6 169 ++init_flag;
benson516 7:6fc812e342e6 170 }
benson516 8:3882cb4be9d3 171 void ATTITUDE::iterateOnce(const vector<float> &y_acce_in, const vector<float> &omega_in) // Main alogorithm
benson516 7:6fc812e342e6 172 {
benson516 8:3882cb4be9d3 173 enable_magEst = false; // no magenetometers input
benson516 8:3882cb4be9d3 174 // Input mapping
benson516 8:3882cb4be9d3 175 InputMapping(y_acce, y_acce_in, accMap_real2here);
benson516 8:3882cb4be9d3 176 // InputMapping(y_mag, y_mag_in, magMap_real2here);
benson516 7:6fc812e342e6 177 InputMapping(omega, omega_in, gyroMap_real2here);
benson516 7:6fc812e342e6 178
benson516 7:6fc812e342e6 179 // Input filter
benson516 8:3882cb4be9d3 180 y_acce = lpfv_y_acce.filter(y_acce);
benson516 8:3882cb4be9d3 181 // y_mag = lpfv_y_mag.filter(y_mag);
benson516 7:6fc812e342e6 182 // omega = lpfv_w.filter(omega);
benson516 7:6fc812e342e6 183
benson516 7:6fc812e342e6 184 // gyro-bias estimation
benson516 7:6fc812e342e6 185 if (enable_biasEst){
benson516 8:3882cb4be9d3 186 omega = Get_VectorPlus(omega, gyroBias_est, true); // minus, omega - gyroBias_est
benson516 7:6fc812e342e6 187 }
benson516 7:6fc812e342e6 188
benson516 7:6fc812e342e6 189 //
benson516 7:6fc812e342e6 190 if(init_flag < 3){
benson516 8:3882cb4be9d3 191 Init();
benson516 7:6fc812e342e6 192 }
benson516 7:6fc812e342e6 193 else{
benson516 8:3882cb4be9d3 194 // Estimation kernel process
benson516 8:3882cb4be9d3 195 EstimationKernel(xg_est, y_acce, omega);
benson516 8:3882cb4be9d3 196 // EstimationKernel(xm_est, y_mag, omega);
benson516 7:6fc812e342e6 197
benson516 7:6fc812e342e6 198 // gyro-bias estimation
benson516 7:6fc812e342e6 199 if (enable_biasEst){
benson516 7:6fc812e342e6 200 updateGyroBiasEst();
benson516 7:6fc812e342e6 201 }
benson516 7:6fc812e342e6 202 }
benson516 7:6fc812e342e6 203 //
benson516 8:3882cb4be9d3 204 Vectors_to_EulerAngle(xg_est,xm_est);
benson516 8:3882cb4be9d3 205 }
benson516 8:3882cb4be9d3 206 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 207 {
benson516 8:3882cb4be9d3 208 enable_magEst = true; // with magenetometers input
benson516 8:3882cb4be9d3 209 // Input mapping
benson516 8:3882cb4be9d3 210 InputMapping(y_acce, y_acce_in, accMap_real2here);
benson516 8:3882cb4be9d3 211 InputMapping(y_mag, y_mag_in, magMap_real2here);
benson516 8:3882cb4be9d3 212 InputMapping(omega, omega_in, gyroMap_real2here);
benson516 8:3882cb4be9d3 213
benson516 8:3882cb4be9d3 214 // Input filter
benson516 8:3882cb4be9d3 215 y_acce = lpfv_y_acce.filter(y_acce);
benson516 8:3882cb4be9d3 216 // y_mag = lpfv_y_mag.filter(y_mag);
benson516 8:3882cb4be9d3 217 // omega = lpfv_w.filter(omega);
benson516 8:3882cb4be9d3 218
benson516 8:3882cb4be9d3 219 // gyro-bias estimation
benson516 8:3882cb4be9d3 220 if (enable_biasEst){
benson516 8:3882cb4be9d3 221 omega = Get_VectorPlus(omega, gyroBias_est, true); // minus, omega - gyroBias_est
benson516 8:3882cb4be9d3 222 }
benson516 8:3882cb4be9d3 223
benson516 8:3882cb4be9d3 224 //
benson516 8:3882cb4be9d3 225 if(init_flag < 3){
benson516 8:3882cb4be9d3 226 Init();
benson516 8:3882cb4be9d3 227 }
benson516 8:3882cb4be9d3 228 else{
benson516 8:3882cb4be9d3 229 // Estimation kernel process
benson516 8:3882cb4be9d3 230 EstimationKernel(xg_est, y_acce, omega);
benson516 8:3882cb4be9d3 231 EstimationKernel(xm_est, y_mag, omega);
benson516 8:3882cb4be9d3 232
benson516 8:3882cb4be9d3 233 // gyro-bias estimation
benson516 8:3882cb4be9d3 234 if (enable_biasEst){
benson516 8:3882cb4be9d3 235 updateGyroBiasEst();
benson516 8:3882cb4be9d3 236 }
benson516 8:3882cb4be9d3 237 }
benson516 8:3882cb4be9d3 238 //
benson516 8:3882cb4be9d3 239 Vectors_to_EulerAngle(xg_est,xm_est);
benson516 7:6fc812e342e6 240 }
benson516 7:6fc812e342e6 241 // transform the x_est into "real" coordinate
benson516 7:6fc812e342e6 242 void ATTITUDE::getEstimation_realCoordinate(vector<float> &V_out){
benson516 8:3882cb4be9d3 243 OutputMapping(V_out,xg_est,accMap_real2here);
benson516 7:6fc812e342e6 244 }
benson516 7:6fc812e342e6 245 // Get Eular angles
benson516 7:6fc812e342e6 246 float ATTITUDE::pitch_deg(void){
benson516 7:6fc812e342e6 247 return (rad2deg*pitch);
benson516 7:6fc812e342e6 248 }
benson516 7:6fc812e342e6 249 float ATTITUDE::roll_deg(void){
benson516 7:6fc812e342e6 250 return (rad2deg*roll);
benson516 7:6fc812e342e6 251 }
benson516 7:6fc812e342e6 252 float ATTITUDE::yaw_deg(void){
benson516 7:6fc812e342e6 253 return (rad2deg*yaw);
benson516 7:6fc812e342e6 254 }
benson516 7:6fc812e342e6 255
benson516 7:6fc812e342e6 256 // Private methods
benson516 7:6fc812e342e6 257 ////////////////////////////////////
benson516 7:6fc812e342e6 258 // Input/output coordinate transformations within the different definitions between the "real" one and the "here" one
benson516 6:c362ed165c39 259 // real -> here
benson516 6:c362ed165c39 260 void ATTITUDE::InputMapping(vector<float> &v_hereDef, const vector<float> &v_realDef, const vector<int> &map_real2here){
benson516 6:c362ed165c39 261 // The map from "real" coordinate to "here" coordinate
benson516 6:c362ed165c39 262 // eg. accMap_real2here = [3,-1,-2];
benson516 6:c362ed165c39 263 // means: real -> here
benson516 6:c362ed165c39 264 // 1 x z 3
benson516 6:c362ed165c39 265 // 2 y -x -1
benson516 6:c362ed165c39 266 // 3 z -y -2
benson516 6:c362ed165c39 267 // vector<int> accMap_real2here = {3,-1,-2};
benson516 6:c362ed165c39 268 // vector<int> gyroMap_real2here = {3,-1,-2};
benson516 6:c362ed165c39 269
benson516 6:c362ed165c39 270 // Iterate through "real" coordinates
benson516 6:c362ed165c39 271 int idx_here = 1;
benson516 6:c362ed165c39 272 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 273 idx_here = map_real2here[i];
benson516 6:c362ed165c39 274 if (idx_here > 0){
benson516 6:c362ed165c39 275 v_hereDef[idx_here-1] = v_realDef[i];
benson516 6:c362ed165c39 276 }else{
benson516 6:c362ed165c39 277 v_hereDef[-idx_here-1] = -1*v_realDef[i];
benson516 6:c362ed165c39 278 }
benson516 6:c362ed165c39 279 }
benson516 0:8126c86bac2a 280 }
benson516 6:c362ed165c39 281 // here -> real
benson516 6:c362ed165c39 282 void ATTITUDE::OutputMapping(vector<float> &v_realDef, const vector<float> &v_hereDef, const vector<int> &map_real2here){
benson516 6:c362ed165c39 283 // This is the inverse mapping of the InputMapping
benson516 6:c362ed165c39 284
benson516 6:c362ed165c39 285 // The map from "real" coordinate to "here" coordinate
benson516 6:c362ed165c39 286 // eg. accMap_real2here = [3,-1,-2];
benson516 6:c362ed165c39 287 // means: real -> here
benson516 6:c362ed165c39 288 // 1 x z 3
benson516 6:c362ed165c39 289 // 2 y -x -1
benson516 6:c362ed165c39 290 // 3 z -y -2
benson516 6:c362ed165c39 291 // vector<int> accMap_real2here = {3,-1,-2};
benson516 6:c362ed165c39 292 // vector<int> gyroMap_real2here = {3,-1,-2};
benson516 6:c362ed165c39 293
benson516 6:c362ed165c39 294 // Iterate through "real" coordinates
benson516 6:c362ed165c39 295 int idx_here = 1;
benson516 6:c362ed165c39 296 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 297 idx_here = map_real2here[i];
benson516 6:c362ed165c39 298 if (idx_here > 0){
benson516 6:c362ed165c39 299 v_realDef[i] = v_hereDef[idx_here-1];
benson516 6:c362ed165c39 300 }else{
benson516 6:c362ed165c39 301 v_realDef[i] = -1*v_hereDef[-idx_here-1];
benson516 6:c362ed165c39 302 }
benson516 6:c362ed165c39 303 }
benson516 6:c362ed165c39 304 }
benson516 7:6fc812e342e6 305 // The kernel of the estimation process
benson516 7:6fc812e342e6 306 ////////////////////////////////////////
benson516 7:6fc812e342e6 307 void ATTITUDE::EstimationKernel(vector<float> &_x_est_, const vector<float> &_ys_, const vector<float> &_omega_){
benson516 7:6fc812e342e6 308 static vector<float> _w_cross_ys_;
benson516 7:6fc812e342e6 309 Get_CrossProduct3(_w_cross_ys_, _omega_, _ys_);
benson516 8:3882cb4be9d3 310 for(size_t i = 0; i < n; ++i){
benson516 7:6fc812e342e6 311 // x_est_plus[i] = x_est[i] + Ts*( L1_diag[i]*(ys[i] - x_est[i]) - w_cross_ys[i]);
benson516 7:6fc812e342e6 312 _x_est_[i] += Ts*( L1_diag[i]*(_ys_[i] - _x_est_[i]) - _w_cross_ys_[i]);
benson516 6:c362ed165c39 313 }
benson516 6:c362ed165c39 314
benson516 7:6fc812e342e6 315 }
benson516 7:6fc812e342e6 316 void ATTITUDE::updateGyroBiasEst(void){ // Update the gyro bias estimation
benson516 7:6fc812e342e6 317 if (one_over_gamma == 0.0){
benson516 7:6fc812e342e6 318 return;
benson516 7:6fc812e342e6 319 }
benson516 7:6fc812e342e6 320 //
benson516 8:3882cb4be9d3 321 Get_CrossProduct3(ys_cross_x_ys, y_acce, Get_VectorPlus(xg_est,y_acce,true));
benson516 7:6fc812e342e6 322 //
benson516 7:6fc812e342e6 323 gyroBias_est = Get_VectorPlus(gyroBias_est, Get_VectorScalarMultiply(ys_cross_x_ys, (one_over_gamma)), true);
benson516 7:6fc812e342e6 324 }
benson516 6:c362ed165c39 325
benson516 7:6fc812e342e6 326 //////////////////////////////////////// end The kernal of the estimation process
benson516 7:6fc812e342e6 327
benson516 7:6fc812e342e6 328 // Utilities
benson516 7:6fc812e342e6 329 // vector operation
benson516 6:c362ed165c39 330 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 331 {
benson516 7:6fc812e342e6 332 // Check the size
benson516 7:6fc812e342e6 333 if (v_c.size() != n){
benson516 7:6fc812e342e6 334 v_c.resize(n);
benson516 7:6fc812e342e6 335 }
benson516 1:edc7ccfc5562 336 v_c[0] = (-v_a[2]*v_b[1]) + v_a[1]*v_b[2];
benson516 1:edc7ccfc5562 337 v_c[1] = v_a[2]*v_b[0] - v_a[0]*v_b[2];
benson516 6:c362ed165c39 338 v_c[2] = (-v_a[1]*v_b[0]) + v_a[0]*v_b[1];
benson516 1:edc7ccfc5562 339 }
benson516 6:c362ed165c39 340 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 341 {
benson516 6:c362ed165c39 342 static vector<float> v_c(n);
benson516 6:c362ed165c39 343 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 344 if (is_minus){
benson516 6:c362ed165c39 345 v_c[i] = v_a[i] - v_b[i];
benson516 6:c362ed165c39 346 }else{
benson516 6:c362ed165c39 347 v_c[i] = v_a[i] + v_b[i];
benson516 6:c362ed165c39 348 }
benson516 6:c362ed165c39 349 }
benson516 6:c362ed165c39 350 return v_c;
benson516 6:c362ed165c39 351 }
benson516 6:c362ed165c39 352 vector<float> ATTITUDE::Get_VectorScalarMultiply(const vector<float> &v_a, float scale) // scale*v_a
benson516 6:c362ed165c39 353 {
benson516 6:c362ed165c39 354 static vector<float> v_c(n);
benson516 6:c362ed165c39 355 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 356 v_c[i] = scale*v_a[i];
benson516 6:c362ed165c39 357
benson516 6:c362ed165c39 358 }
benson516 6:c362ed165c39 359 return v_c;
benson516 6:c362ed165c39 360 }
benson516 6:c362ed165c39 361 float ATTITUDE::Get_Vector3Norm(const vector<float> &v_in)
benson516 1:edc7ccfc5562 362 {
benson516 1:edc7ccfc5562 363 float temp = 0.0;
benson516 6:c362ed165c39 364
benson516 6:c362ed165c39 365 for (size_t i = 0; i < n; ++i)
benson516 1:edc7ccfc5562 366 temp += v_in[i]*v_in[i];
benson516 6:c362ed165c39 367 return sqrt(temp); // <- Should check if this function is available (?)
benson516 1:edc7ccfc5562 368 }
benson516 6:c362ed165c39 369 void ATTITUDE::Normolization(vector<float> &V_out, const vector<float> &V_in){
benson516 6:c362ed165c39 370 float norm = Get_Vector3Norm(V_in);
benson516 6:c362ed165c39 371 for (size_t i = 0; i < n; ++i){
benson516 6:c362ed165c39 372 V_out[i] = V_in[i]/norm;
benson516 6:c362ed165c39 373 }
benson516 6:c362ed165c39 374 }