float center_axis0 = this->arc_milestone[this->plane_axis_0] + offset[this->plane_axis_0];
float center_axis1 = this->arc_milestone[this->plane_axis_1] + offset[this->plane_axis_1];
float linear_travel = target[this->plane_axis_2] - this->arc_milestone[this->plane_axis_2];
- float r_axis0 = -offset[this->plane_axis_0]; // Radius vector from center to current location
+ float r_axis0 = -offset[this->plane_axis_0]; // Radius vector from center to start position
float r_axis1 = -offset[this->plane_axis_1];
- float rt_axis0 = target[this->plane_axis_0] - this->arc_milestone[this->plane_axis_0] - offset[this->plane_axis_0];
+ float rt_axis0 = target[this->plane_axis_0] - this->arc_milestone[this->plane_axis_0] - offset[this->plane_axis_0]; // Radius vector from center to target position
float rt_axis1 = target[this->plane_axis_1] - this->arc_milestone[this->plane_axis_1] - offset[this->plane_axis_1];
float angular_travel = 0;
-
+ //check for condition where atan2 formula will fail due to everything canceling out exactly
if((this->arc_milestone[this->plane_axis_0]==target[this->plane_axis_0]) && (this->arc_milestone[this->plane_axis_1]==target[this->plane_axis_1])) {
- if (is_clockwise) {
+ if (is_clockwise) { // set angular_travel to -2pi for a clockwise full circle
angular_travel = (-2 * PI);
- } else {
+ } else { // set angular_travel to 2pi for a counterclockwise full circle
angular_travel = (2 * PI);
}
} else {
// Patch from GRBL Firmware - Christoph Baumann 04072015
// CCW angle between position and target from circle center. Only one atan2() trig computation required.
- // Only run if not a full circle
+ // Only run if not a full circle or angular travel will incorrectly result in 0.0f
angular_travel = atan2f(r_axis0 * rt_axis1 - r_axis1 * rt_axis0, r_axis0 * rt_axis0 + r_axis1 * rt_axis1);
if (plane_axis_2 == Y_AXIS) { is_clockwise = !is_clockwise; } //Math for XZ plane is reverse of other 2 planes
- if (is_clockwise) { // Correct atan2 output per direction
+ if (is_clockwise) { // adjust angular_travel to be in the range of -2pi to 0 for clockwise arcs
if (angular_travel > 0) { angular_travel -= (2 * PI); }
- } else {
+ } else { // adjust angular_travel to be in the range of 0 to 2pi for counterclockwise arcs
if (angular_travel < 0) { angular_travel += (2 * PI); }
}
}
-
+
// Find the distance for this gcode
float millimeters_of_travel = hypotf(angular_travel * radius, fabsf(linear_travel));