+double RobomonAtlantis::distanceToCircularObstacleHokuyo(int beamnum, Point center, double diameter)
+{
+ struct robot_pos_type e = orte.est_pos_best;
+ double sensor_a;
+ struct sharp_pos s;
+
+ s.x = HOKUYO_CENTER_OFFSET_M;
+ s.y = 0.0;
+ s.ang = HOKUYO_INDEX_TO_RAD(beamnum);
+
+ Point sensor(e.x + s.x*cos(e.phi) - s.y*sin(e.phi),
+ e.y + s.x*sin(e.phi) + s.y*cos(e.phi));
+ sensor_a = e.phi + s.ang;
+
+ const double sensorRange = 4.0; /*[meters]*/
+
+ double distance = sensorRange;
+ double angle;
+
+ angle = sensor.angleTo(center) - sensor_a;
+ angle = fmod(angle, 2.0*M_PI);
+ if (angle > +M_PI) angle -= 2.0*M_PI;
+ if (angle < -M_PI) angle += 2.0*M_PI;
+ angle = fabs(angle);
+
+ double k = tan(sensor_a);
+ double r = diameter / 2.0;
+
+ double A = 1 + k*k;
+ double B = 2 * (sensor.y*k - center.x - k*k*sensor.x - center.y*k);
+ double C = center.x*center.x + center.y*center.y +
+ k*k*sensor.x*sensor.x - 2*sensor.y*k*sensor.x +
+ sensor.y*sensor.y + 2*k*sensor.x*center.y -
+ 2*sensor.y*center.y - r*r;
+
+ double D = B*B - 4*A*C;
+
+ if (D > 0) {
+ Point ob1, ob2;
+
+ ob1.x = (-B + sqrt(D)) / (2*A);
+ ob2.x = (-B - sqrt(D)) / (2*A);
+ ob1.y = k * (ob1.x - sensor.x) + sensor.y;
+ ob2.y = k * (ob2.x - sensor.x) + sensor.y;
+
+ double distance1 = sensor.distanceTo(ob1);
+ double distance2 = sensor.distanceTo(ob2);
+ distance = (distance1 < distance2) ? distance1 : distance2;
+ } else if (D == 0) {
+ Point ob;
+ ob.x = -B / (2*A);
+ ob.y = k * (ob.x - sensor.x) + sensor.y;
+ distance = sensor.distanceTo(ob);
+ }
+ distance = distance + (drand48()-0.5)*3.0e-2;
+ if (D < 0 || angle > atan(r / distance))
+ distance = sensorRange;
+ if (distance > sensorRange)
+ distance = sensorRange;
+
+ return distance;
+}
+
+/**