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Checkpoint: Working, but non-verified full mag calibration
This commit is contained in:
Lorenz Meier
@@ -0,0 +1,175 @@
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#include <math.h>
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#include "calibration_routines.h"
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int sphere_fit_least_squares(const float x[], const float y[], const float z[],
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unsigned int size, unsigned int max_iterations, float delta, float *sphere_x, float *sphere_y, float *sphere_z, float *sphere_radius) {
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float x_sumplain = 0.0f;
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float x_sumsq = 0.0f;
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float x_sumcube = 0.0f;
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float y_sumplain = 0.0f;
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float y_sumsq = 0.0f;
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float y_sumcube = 0.0f;
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float z_sumplain = 0.0f;
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float z_sumsq = 0.0f;
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float z_sumcube = 0.0f;
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float xy_sum = 0.0f;
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float xz_sum = 0.0f;
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float yz_sum = 0.0f;
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float x2y_sum = 0.0f;
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float x2z_sum = 0.0f;
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float y2x_sum = 0.0f;
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float y2z_sum = 0.0f;
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float z2x_sum = 0.0f;
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float z2y_sum = 0.0f;
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for (unsigned int i = 0; i < size; i++) {
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float x2 = x[i] * x[i];
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float y2 = y[i] * y[i];
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float z2 = z[i] * z[i];
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x_sumplain += x[i];
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x_sumsq += x2;
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x_sumcube += x2 * x[i];
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y_sumplain += y[i];
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y_sumsq += y2;
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y_sumcube += y2 * y[i];
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z_sumplain += z[i];
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z_sumsq += z2;
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z_sumcube += z2 * z[i];
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xy_sum += x[i] * y[i];
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xz_sum += x[i] * z[i];
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yz_sum += y[i] * z[i];
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x2y_sum += x2 * y[i];
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x2z_sum += x2 * z[i];
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y2x_sum += y2 * x[i];
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y2z_sum += y2 * z[i];
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z2x_sum += z2 * x[i];
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z2y_sum += z2 * y[i];
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}
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//
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//Least Squares Fit a sphere A,B,C with radius squared Rsq to 3D data
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//
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// P is a structure that has been computed with the data earlier.
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// P.npoints is the number of elements; the length of X,Y,Z are identical.
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// P's members are logically named.
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//
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// X[n] is the x component of point n
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// Y[n] is the y component of point n
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// Z[n] is the z component of point n
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//
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// A is the x coordiante of the sphere
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// B is the y coordiante of the sphere
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// C is the z coordiante of the sphere
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// Rsq is the radius squared of the sphere.
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//
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//This method should converge; maybe 5-100 iterations or more.
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//
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float x_sum = x_sumplain / size; //sum( X[n] )
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float x_sum2 = x_sumsq / size; //sum( X[n]^2 )
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float x_sum3 = x_sumcube / size; //sum( X[n]^3 )
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float y_sum = y_sumplain / size; //sum( Y[n] )
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float y_sum2 = y_sumsq / size; //sum( Y[n]^2 )
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float y_sum3 = y_sumcube / size; //sum( Y[n]^3 )
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float z_sum = z_sumplain / size; //sum( Z[n] )
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float z_sum2 = z_sumsq / size; //sum( Z[n]^2 )
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float z_sum3 = z_sumcube / size; //sum( Z[n]^3 )
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float XY = xy_sum / size; //sum( X[n] * Y[n] )
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float XZ = xz_sum / size; //sum( X[n] * Z[n] )
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float YZ = yz_sum / size; //sum( Y[n] * Z[n] )
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float X2Y = x2y_sum / size; //sum( X[n]^2 * Y[n] )
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float X2Z = x2z_sum / size; //sum( X[n]^2 * Z[n] )
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float Y2X = y2x_sum / size; //sum( Y[n]^2 * X[n] )
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float Y2Z = y2z_sum / size; //sum( Y[n]^2 * Z[n] )
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float Z2X = z2x_sum / size; //sum( Z[n]^2 * X[n] )
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float Z2Y = z2y_sum / size; //sum( Z[n]^2 * Y[n] )
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//Reduction of multiplications
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float F0 = x_sum2 + y_sum2 + z_sum2;
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float F1 = 0.5f * F0;
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float F2 = -8.0f * (x_sum3 + Y2X + Z2X);
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float F3 = -8.0f * (X2Y + y_sum3 + Z2Y);
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float F4 = -8.0f * (X2Z + Y2Z + z_sum3);
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//Set initial conditions:
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float A = x_sum;
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float B = y_sum;
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float C = z_sum;
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//First iteration computation:
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float A2 = A*A;
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float B2 = B*B;
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float C2 = C*C;
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float QS = A2 + B2 + C2;
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float QB = -2.0f * (A*x_sum + B*y_sum + C*z_sum);
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//Set initial conditions:
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float Rsq = F0 + QB + QS;
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//First iteration computation:
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float Q0 = 0.5f * (QS - Rsq);
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float Q1 = F1 + Q0;
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float Q2 = 8.0f * ( QS - Rsq + QB + F0 );
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float aA,aB,aC,nA,nB,nC,dA,dB,dC;
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//Iterate N times, ignore stop condition.
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int n = 0;
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while( n < max_iterations ){
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n++;
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//Compute denominator:
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aA = Q2 + 16.0f * (A2 - 2.0f * A*x_sum + x_sum2);
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aB = Q2 + 16.0f *(B2 - 2.0f * B*y_sum + y_sum2);
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aC = Q2 + 16.0f *(C2 - 2.0f * C*z_sum + z_sum2);
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aA = (aA == 0.0f) ? 1.0f : aA;
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aB = (aB == 0.0f) ? 1.0f : aB;
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aC = (aC == 0.0f) ? 1.0f : aC;
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//Compute next iteration
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nA = A - ((F2 + 16.0f * ( B*XY + C*XZ + x_sum*(-A2 - Q0) + A*(x_sum2 + Q1 - C*z_sum - B*y_sum) ) )/aA);
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nB = B - ((F3 + 16.0f * ( A*XY + C*YZ + y_sum*(-B2 - Q0) + B*(y_sum2 + Q1 - A*x_sum - C*z_sum) ) )/aB);
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nC = C - ((F4 + 16.0f * ( A*XZ + B*YZ + z_sum*(-C2 - Q0) + C*(z_sum2 + Q1 - A*x_sum - B*y_sum) ) )/aC);
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//Check for stop condition
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dA = (nA - A);
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dB = (nB - B);
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dC = (nC - C);
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if( (dA*dA + dB*dB + dC*dC) <= delta ){ break; }
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//Compute next iteration's values
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A = nA;
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B = nB;
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C = nC;
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A2 = A*A;
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B2 = B*B;
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C2 = C*C;
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QS = A2 + B2 + C2;
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QB = -2.0f * (A*x_sum + B*y_sum + C*z_sum);
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Rsq = F0 + QB + QS;
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Q0 = 0.5f * (QS - Rsq);
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Q1 = F1 + Q0;
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Q2 = 8.0f * ( QS - Rsq + QB + F0 );
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}
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*sphere_x = A;
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*sphere_y = B;
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*sphere_z = C;
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*sphere_radius = sqrtf(Rsq);
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return 0;
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}
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@@ -0,0 +1,21 @@
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/**
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* Least-squares fit of a sphere to a set of points.
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*
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* Fits a sphere to a set of points on the sphere surface.
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*
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* @param x point coordinates on the X axis
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* @param y point coordinates on the Y axis
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* @param z point coordinates on the Z axis
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* @param size number of points
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* @param max_iterations abort if maximum number of iterations have been reached. If unsure, set to 100.
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* @param delta abort if error is below delta. If unsure, set to 0 to run max_iterations times.
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* @param sphere_x coordinate of the sphere center on the X axis
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* @param sphere_y coordinate of the sphere center on the Y axis
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* @param sphere_z coordinate of the sphere center on the Z axis
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* @param sphere_radius sphere radius
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*
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* @return 0 on success, 1 on failure
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*/
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int sphere_fit_least_squares(const float x[], const float y[], const float z[],
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unsigned int size, unsigned int max_iterations, float delta, float *sphere_x, float *sphere_y, float *sphere_z, float *sphere_radius);
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+117
-81
@@ -83,6 +83,8 @@
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#include <drivers/drv_mag.h>
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#include <drivers/drv_baro.h>
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#include "calibration_routines.h"
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PARAM_DEFINE_INT32(SYS_FAILSAVE_LL, 0); /**< Go into low-level failsafe after 0 ms */
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//PARAM_DEFINE_INT32(SYS_FAILSAVE_HL, 0); /**< Go into high-level failsafe after 0 ms */
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@@ -288,8 +290,9 @@ void do_mag_calibration(int status_pub, struct vehicle_status_s *status)
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status->flag_preflight_mag_calibration = true;
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state_machine_publish(status_pub, status, mavlink_fd);
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int sub_sensor_combined = orb_subscribe(ORB_ID(sensor_combined));
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struct sensor_combined_s raw;
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int sub_mag = orb_subscribe(ORB_ID(sensor_mag));
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orb_set_interval(sub_mag, 22);
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struct mag_report mag;
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/* 30 seconds */
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uint64_t calibration_interval = 45 * 1000 * 1000;
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@@ -306,8 +309,7 @@ void do_mag_calibration(int status_pub, struct vehicle_status_s *status)
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int fd = open(MAG_DEVICE_PATH, 0);
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/* erase old calibration */
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struct mag_scale mscale_null = {
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0.0f,
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1.0f,
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@@ -321,8 +323,15 @@ void do_mag_calibration(int status_pub, struct vehicle_status_s *status)
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mavlink_log_info(mavlink_fd, "[commander] failed to set scale / offsets for mag");
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}
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/* calibrate range */
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if (OK != ioctl(fd, MAGIOCCALIBRATE, fd)) {
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warnx("failed to calibrate scale");
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}
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close(fd);
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/* calibrate offsets */
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uint64_t calibration_start = hrt_absolute_time();
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uint64_t axis_deadline = hrt_absolute_time();
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@@ -331,10 +340,16 @@ void do_mag_calibration(int status_pub, struct vehicle_status_s *status)
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const char axislabels[3] = { 'Z', 'X', 'Y'};
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int axis_index = -1;
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while (hrt_absolute_time() < calibration_deadline) {
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const int calibration_maxcount = 2000;
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float *x = malloc(sizeof(float) * calibration_maxcount);
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float *y = malloc(sizeof(float) * calibration_maxcount);
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float *z = malloc(sizeof(float) * calibration_maxcount);
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while (hrt_absolute_time() < calibration_deadline &&
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calibration_counter < calibration_maxcount) {
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/* wait blocking for new data */
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struct pollfd fds[1] = { { .fd = sub_sensor_combined, .events = POLLIN } };
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struct pollfd fds[1] = { { .fd = sub_mag, .events = POLLIN } };
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/* user guidance */
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if (hrt_absolute_time() >= axis_deadline &&
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@@ -363,30 +378,34 @@ void do_mag_calibration(int status_pub, struct vehicle_status_s *status)
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// }
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if (poll(fds, 1, 1000)) {
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orb_copy(ORB_ID(sensor_combined), sub_sensor_combined, &raw);
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orb_copy(ORB_ID(sensor_mag), sub_mag, &mag);
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x[calibration_counter] = mag.x;
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y[calibration_counter] = mag.y;
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z[calibration_counter] = mag.z;
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/* get min/max values */
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/* ignore other axes */
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if (raw.magnetometer_ga[0] < mag_min[0]) {
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mag_min[0] = raw.magnetometer_ga[0];
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}
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else if (raw.magnetometer_ga[0] > mag_max[0]) {
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mag_max[0] = raw.magnetometer_ga[0];
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}
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// if (mag.x < mag_min[0]) {
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// mag_min[0] = mag.x;
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// }
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// else if (mag.x > mag_max[0]) {
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// mag_max[0] = mag.x;
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// }
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if (raw.magnetometer_ga[1] < mag_min[1]) {
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mag_min[1] = raw.magnetometer_ga[1];
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}
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else if (raw.magnetometer_ga[1] > mag_max[1]) {
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mag_max[1] = raw.magnetometer_ga[1];
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}
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// if (raw.magnetometer_ga[1] < mag_min[1]) {
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// mag_min[1] = raw.magnetometer_ga[1];
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// }
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// else if (raw.magnetometer_ga[1] > mag_max[1]) {
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// mag_max[1] = raw.magnetometer_ga[1];
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// }
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if (raw.magnetometer_ga[2] < mag_min[2]) {
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mag_min[2] = raw.magnetometer_ga[2];
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}
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else if (raw.magnetometer_ga[2] > mag_max[2]) {
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mag_max[2] = raw.magnetometer_ga[2];
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}
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// if (raw.magnetometer_ga[2] < mag_min[2]) {
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// mag_min[2] = raw.magnetometer_ga[2];
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// }
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// else if (raw.magnetometer_ga[2] > mag_max[2]) {
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// mag_max[2] = raw.magnetometer_ga[2];
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// }
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calibration_counter++;
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} else {
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@@ -396,76 +415,89 @@ void do_mag_calibration(int status_pub, struct vehicle_status_s *status)
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}
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}
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/* disable calibration mode */
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status->flag_preflight_mag_calibration = false;
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state_machine_publish(status_pub, status, mavlink_fd);
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float sphere_x;
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float sphere_y;
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float sphere_z;
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float sphere_radius;
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float mag_offset[3];
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sphere_fit_least_squares(x, y, z, calibration_counter, 100, 0.0f, &sphere_x, &sphere_y, &sphere_z, &sphere_radius);
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/**
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* The offset is subtracted from the sensor values, so the result is the
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* POSITIVE number that has to be subtracted from the sensor data
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* to shift the center to zero
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*
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* offset = max - ((max - min) / 2.0f)
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* max - max/2 + min/2
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* max/2 + min/2
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*
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* which reduces to
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*
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* offset = (max + min) / 2.0f
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*/
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free(x);
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free(y);
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free(z);
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mag_offset[0] = (mag_max[0] + mag_min[0]) / 2.0f;
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mag_offset[1] = (mag_max[1] + mag_min[1]) / 2.0f;
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mag_offset[2] = (mag_max[2] + mag_min[2]) / 2.0f;
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float mag_offset[3] = {sphere_x, sphere_y, sphere_z};
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// *
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// * The offset is subtracted from the sensor values, so the result is the
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// * POSITIVE number that has to be subtracted from the sensor data
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// * to shift the center to zero
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// *
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// * offset = max - ((max - min) / 2.0f)
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// * max - max/2 + min/2
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// * max/2 + min/2
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// *
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// * which reduces to
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// *
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// * offset = (max + min) / 2.0f
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// mag_offset[0] = (mag_max[0] + mag_min[0]) / 2.0f;
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// mag_offset[1] = (mag_max[1] + mag_min[1]) / 2.0f;
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// mag_offset[2] = (mag_max[2] + mag_min[2]) / 2.0f;
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if (isfinite(mag_offset[0]) && isfinite(mag_offset[1]) && isfinite(mag_offset[2])) {
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/* announce and set new offset */
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if (param_set(param_find("SENS_MAG_XOFF"), &(mag_offset[0]))) {
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fprintf(stderr, "[commander] Setting X mag offset failed!\n");
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}
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if (param_set(param_find("SENS_MAG_YOFF"), &(mag_offset[1]))) {
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fprintf(stderr, "[commander] Setting Y mag offset failed!\n");
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}
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if (param_set(param_find("SENS_MAG_ZOFF"), &(mag_offset[2]))) {
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fprintf(stderr, "[commander] Setting Z mag offset failed!\n");
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}
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if (param_set(param_find("SENS_MAG_XSCALE"), &(mag_offset[0]))) {
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fprintf(stderr, "[commander] Setting X mag offset failed!\n");
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}
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if (param_set(param_find("SENS_MAG_YSCALE"), &(mag_offset[1]))) {
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fprintf(stderr, "[commander] Setting Y mag offset failed!\n");
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}
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if (param_set(param_find("SENS_MAG_ZSCALE"), &(mag_offset[2]))) {
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fprintf(stderr, "[commander] Setting Z mag offset failed!\n");
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}
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fd = open(MAG_DEVICE_PATH, 0);
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struct mag_scale mscale = {
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mag_offset[0],
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1.0f,
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mag_offset[1],
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1.0f,
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mag_offset[2],
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1.0f,
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};
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struct mag_scale mscale;
|
||||
|
||||
if (OK != ioctl(fd, MAGIOCGSCALE, (long unsigned int)&mscale))
|
||||
warn("WARNING: failed to get scale / offsets for mag");
|
||||
|
||||
mscale.x_offset = mag_offset[0];
|
||||
mscale.y_offset = mag_offset[1];
|
||||
mscale.z_offset = mag_offset[2];
|
||||
|
||||
if (OK != ioctl(fd, MAGIOCSSCALE, (long unsigned int)&mscale))
|
||||
warn("WARNING: failed to set scale / offsets for mag");
|
||||
close(fd);
|
||||
|
||||
/* announce and set new offset */
|
||||
|
||||
if (param_set(param_find("SENS_MAG_XOFF"), &(mscale.x_offset))) {
|
||||
fprintf(stderr, "[commander] Setting X mag offset failed!\n");
|
||||
}
|
||||
|
||||
if (param_set(param_find("SENS_MAG_YOFF"), &(mscale.y_offset))) {
|
||||
fprintf(stderr, "[commander] Setting Y mag offset failed!\n");
|
||||
}
|
||||
|
||||
if (param_set(param_find("SENS_MAG_ZOFF"), &(mscale.z_offset))) {
|
||||
fprintf(stderr, "[commander] Setting Z mag offset failed!\n");
|
||||
}
|
||||
|
||||
if (param_set(param_find("SENS_MAG_XSCALE"), &(mscale.x_scale))) {
|
||||
fprintf(stderr, "[commander] Setting X mag scale failed!\n");
|
||||
}
|
||||
|
||||
if (param_set(param_find("SENS_MAG_YSCALE"), &(mscale.y_scale))) {
|
||||
fprintf(stderr, "[commander] Setting Y mag scale failed!\n");
|
||||
}
|
||||
|
||||
if (param_set(param_find("SENS_MAG_ZSCALE"), &(mscale.z_scale))) {
|
||||
fprintf(stderr, "[commander] Setting Z mag scale failed!\n");
|
||||
}
|
||||
|
||||
/* auto-save to EEPROM */
|
||||
int save_ret = pm_save_eeprom(false);
|
||||
if(save_ret != 0) {
|
||||
warn("WARNING: auto-save of params to EEPROM failed");
|
||||
}
|
||||
|
||||
printf("[mag cal] scale: %.6f %.6f %.6f\n\t\toffset: %.6f %.6f %.6f\nradius: %.6f GA\n",
|
||||
mscale.x_scale, mscale.y_scale, mscale.z_scale,
|
||||
mscale.x_offset, mscale.y_offset, mscale.z_offset, sphere_radius);
|
||||
|
||||
// char buf[50];
|
||||
// sprintf(buf, "[commander] mag cal: x:%d y:%d z:%d mGa", (int)(mag_offset[0]*1000), (int)(mag_offset[1]*1000), (int)(mag_offset[2]*1000));
|
||||
@@ -475,7 +507,11 @@ void do_mag_calibration(int status_pub, struct vehicle_status_s *status)
|
||||
mavlink_log_info(mavlink_fd, "[commander] mag calibration FAILED (NaN)");
|
||||
}
|
||||
|
||||
close(sub_sensor_combined);
|
||||
/* disable calibration mode */
|
||||
status->flag_preflight_mag_calibration = false;
|
||||
state_machine_publish(status_pub, status, mavlink_fd);
|
||||
|
||||
close(sub_mag);
|
||||
}
|
||||
|
||||
void do_gyro_calibration(int status_pub, struct vehicle_status_s *status)
|
||||
|
||||
Reference in New Issue
Block a user