+/**
+ * do a superb curve joining line1 to line2 which is composed of:
+ * - a clothoid starting from line1
+ * - a circle
+ * - another clothoid up to line2
+ *
+ * the function assumes that the initial linear speed is Vd and
+ * angular speed is 0.
+ *
+ * - alpha: total angle
+ * - beta: circular part of angle (lower than alpha)
+ * - R: the radius of the circle (must be != 0)
+ * - Vd: linear speed to use (in imp per cs period)
+ * - Amax: maximum angular acceleration
+ * - d_inter: distance in mm until the intersection of the
+ * 2 lines
+ *
+ * return 0 on success: in this case these parameters are filled:
+ * - Aa_out: the angular acceleration to configure in quadramp
+ * - remain_d_mm_out: remaining distance before start to turn
+ */
+uint8_t clitoid(double alpha_deg, double beta_deg, double R_mm,
+ double Vd, double Amax, double d_inter_mm)
+{
+ double Vd_mm_s;
+ double Va, Va_rd_s;
+ double t, d_mm, alpha_rad, beta_rad;
+ double remain_d_mm;
+ double Aa, Aa_rd_s2;
+ line_t line1, line2;
+ double x, y, a_rad;
+ point_t robot, intersect, pt2, center, proj;
+ vect_t v;
+
+ /* param check */
+ if (fabs(alpha_deg) <= fabs(beta_deg)) {
+ DEBUG(E_USER_STRAT, "alpha is smaller than beta");
+ return END_ERROR;
+ }
+
+ /* get angular speed Va */
+ Vd_mm_s = Vd * (CS_HZ/DIST_IMP_MM);
+ DEBUG(E_USER_STRAT, "Vd_mm_s=%2.2f", Vd_mm_s);
+ Va_rd_s = Vd_mm_s / R_mm;
+ Va = Va_rd_s * (DIST_IMP_MM * EXT_TRACK_MM / (2 * CS_HZ));
+ DEBUG(E_USER_STRAT, "Va_rd_s=%2.2f Va=%2.2f", Va_rd_s, Va);
+
+ /* process 't', the time in seconds that we will take to do
+ * the first clothoid */
+ alpha_rad = RAD(alpha_deg);
+ beta_rad = RAD(beta_deg);
+ t = fabs(((alpha_rad - beta_rad) * R_mm) / Vd_mm_s);
+ DEBUG(E_USER_STRAT, "R_mm=%2.2f alpha_rad=%2.2f beta_rad=%2.2f t=%2.2f",
+ R_mm, alpha_rad, beta_rad, t);
+
+ /* process the angular acceleration */
+ Aa_rd_s2 = Va_rd_s / t;
+ Aa = Aa_rd_s2 * (DIST_IMP_MM * EXT_TRACK_MM /
+ (2 * CS_HZ * CS_HZ));
+ DEBUG(E_USER_STRAT, "Aa_rd_s2=%2.2f Aa=%2.2f", Aa_rd_s2, Aa);
+
+ /* exit if the robot cannot physically do it */
+ if (Aa > Amax) {
+ DEBUG(E_USER_STRAT, "greater than max acceleration");
+ return END_ERROR;
+ }
+
+ /* the robot position */
+ x = position_get_x_double(&mainboard.pos);
+ y = position_get_y_double(&mainboard.pos);
+ a_rad = position_get_a_rad_double(&mainboard.pos);
+
+ /* define line1 and line2 */
+ robot.x = x;
+ robot.y = y;
+ intersect.x = x + cos(a_rad) * d_inter_mm;
+ intersect.y = y + sin(a_rad) * d_inter_mm;
+ pts2line(&robot, &intersect, &line1);
+ pt2.x = intersect.x + cos(a_rad + alpha_rad);
+ pt2.y = intersect.y + sin(a_rad + alpha_rad);
+ pts2line(&intersect, &pt2, &line2);
+ DEBUG(E_USER_STRAT, "intersect=(%2.2f, %2.2f)",
+ intersect.x, intersect.y);
+
+ /* the center of the circle is at (d_mm, d_mm) when we have to
+ * start the clothoid */
+ d_mm = R_mm * sqrt(fabs(alpha_rad - beta_rad)) *
+ sqrt(M_PI) / 2.;
+ DEBUG(E_USER_STRAT, "d_mm=%2.2f", d_mm);
+
+ /* translate line1 */
+ v.x = intersect.x - robot.x;
+ v.y = intersect.y - robot.y;
+ if (a_rad > 0)
+ vect_rot_trigo(&v);
+ else
+ vect_rot_retro(&v);
+ vect_resize(&v, d_mm);
+ line_translate(&line1, &v);
+
+ /* translate line2 */
+ v.x = intersect.x - pt2.x;
+ v.y = intersect.y - pt2.y;
+ if (a_rad > 0)
+ vect_rot_trigo(&v);
+ else
+ vect_rot_retro(&v);
+ vect_resize(&v, d_mm);
+ line_translate(&line2, &v);
+
+ /* find the center of the circle, at the intersection of the
+ * new translated lines */
+ if (intersect_line(&line1, &line2, ¢er) != 1) {
+ DEBUG(E_USER_STRAT, "cannot find circle center");
+ return END_ERROR;
+ }
+ DEBUG(E_USER_STRAT, "center=(%2.2f,%2.2f)", center.x, center.y);
+
+ /* project center of circle on line1 */
+ proj_pt_line(¢er, &line1, &proj);
+ DEBUG(E_USER_STRAT, "proj=(%2.2f,%2.2f)", proj.x, proj.y);
+
+ /* process remaining distance before start turning */
+ remain_d_mm = d_inter_mm - (pt_norm(&proj, &intersect) + d_mm);
+ DEBUG(E_USER_STRAT, "remain_d=%2.2f", remain_d_mm);
+ if (remain_d_mm < 0) {
+ DEBUG(E_USER_STRAT, "too late, cannot turn");
+ return END_ERROR;
+ }
+
+ return END_TRAJ;
+}
+
git.droids-corp.org / aversive.git / blobdiff