ManuelW/grbl-LPC-CoreXY
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pace calculation correct, arc algorithm correct, support for negative R

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Simen Svale Skogsrud
2009-02-08 12:24:52 +01:00
parent d012440518
commit 6c3a6a25d5
9 changed files with 45 additions and 7211 deletions
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39
gcode.c
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@ -244,7 +244,7 @@ uint8_t gc_execute_line(char *line) {
switch (gc.motion_mode) {
case MOTION_MODE_CANCEL: break;
case MOTION_MODE_RAPID_LINEAR: case MOTION_MODE_LINEAR:
if (inverse_feed_rate) {
if (gc.inverse_feed_rate_mode) {
mc_linear_motion(target[X_AXIS], target[Y_AXIS], target[Z_AXIS],
inverse_feed_rate, true);
} else {
@ -309,37 +309,40 @@ uint8_t gc_execute_line(char *line) {
double x = target[gc.plane_axis_0]-gc.position[gc.plane_axis_0];
double y = target[gc.plane_axis_1]-gc.position[gc.plane_axis_1];
clear_vector(&offset);
double h_x2_div_d = sqrt(4 * r*r - x*x - y*y)/hypot(x,y); // == h * 2 / d
double h_x2_div_d = -sqrt(4 * r*r - x*x - y*y)/hypot(x,y); // == -(h * 2 / d)
// If r is smaller than d, the arc is now traversing the complex plane beyond the reach of any
// earthly CNC, and thus - for practical reasons - we will terminate promptly:
// real CNC, and thus - for practical reasons - we will terminate promptly:
if(isnan(h_x2_div_d)) { FAIL(GCSTATUS_FLOATING_POINT_ERROR); return(gc.status_code); }
/* The anti-clockwise circle lies to the right of the target direction. When offset is positive,
// Invert the sign of h_x2_div_d if the circle is counter clockwise (see sketch below)
if (gc.motion_mode == MOTION_MODE_CCW_ARC) { h_x2_div_d = -h_x2_div_d; }
/* The counter clockwise circle lies to the left of the target direction. When offset is positive,
the left hand circle will be generated - when it is negative the right hand circle is generated.
T
T <-- Target position
^
|
|
^
Clockwise circles with this center | Clockwise circles with this center will have
will have > 180 deg of angular travel | < 180 deg of angular travel, which is a good thing!
\ | /
center of arc when h_x2_div_d is positive -> x <----- | -----> x <- center of arc when h_x2_div_d is negative
|
|
C */
if (gc.motion_mode == MOTION_MODE_CCW_ARC) { h_x2_div_d = -h_x2_div_d; }
C <-- Current position */
// Negative R is g-code-alese for "I want a circle with more than 180 degrees of travel" (go figure!),
// even though it is advised against ever generating such circles in a single line of g-code. By
// inverting the sign of h_x2_div_d the center of the circles is placed on the opposide side of the line of
// travel and thus we get the unadvisably long circles as prescribed.
if (r < 0) { h_x2_div_d = -h_x2_div_d; }
// Complete the operation by calculating the actual center of the arc
offset[gc.plane_axis_0] = (x-(y*h_x2_div_d))/2;
offset[gc.plane_axis_1] = (y+(x*h_x2_div_d))/2;
// printByte('(');
// printInteger(trunc(offset[gc.plane_axis_0])); printByte(',');
// printInteger(trunc(offset[gc.plane_axis_1]));
// printByte(')');
}
/*
@ -376,7 +379,7 @@ uint8_t gc_execute_line(char *line) {
printString("mc_arc(");
printInteger(trunc(theta_start/M_PI*180)); printByte(',');
printInteger(trunc(angular_travel/M_PI*180)); printByte(',');
printInteger(trunc(radius)); printByte('…');
printInteger(trunc(radius));
printByte(')');
mc_arc(theta_start, angular_travel, radius, gc.plane_axis_0, gc.plane_axis_1, gc.feed_rate);
break;