ManuelW/grbl-LPC-CoreXY
1
0
Fork 0
Code Issues Pull Requests Releases 1 Wiki Activity

Updated README. Max step rate back at 30kHz. Acceleration minor bug fix.

Browse Source 
- Returned the max step rate to 30kHz. The new arc algorithm works uses
so much less CPU overhead, because the segments are longer, that the
planner has no problem computing through them.

- Fixed an issue with the acceleration independence scaling. Should now
work with accelerations above 400mm/sec^2 or so.

- Updated README
This commit is contained in:
Sonny Jeon
2012-12-21 08:51:36 -07:00
parent 3dfffa622d
commit 5e7c25d480
4 changed files with 15 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
motion_control.c
View File

@ -70,7 +70,7 @@ void mc_line(float x, float y, float z, float feed_rate, uint8_t invert_feed_rat
if (sys.abort) { return; } // Bail, if system abort.
} while ( plan_check_full_buffer() );
plan_buffer_line(x, y, z, feed_rate, invert_feed_rate);
// If idle, indicate to the system there is now a planned block in the buffer ready to cycle
// start. Otherwise ignore and continue on.
if (!sys.state) { sys.state = STATE_QUEUED; }
@ -146,8 +146,8 @@ void mc_arc(float *position, float *target, float *offset, uint8_t axis_0, uint8
(second order sin() has too much error) holds for nearly all CNC applications, except for possibly very
small radii (~0.5mm). In other words, theta_per_segment would need to be greater than 0.25 rad(14 deg)
and N_ARC_CORRECTION would need to be large to cause an appreciable drift error (>5% of radius, for very
small radii this is very, very small). N_ARC_CORRECTION~=20 should be more than small enough to correct
for numerical drift error.
small radii, 5% of 0.5mm is very, very small). N_ARC_CORRECTION~=20 should be more than small enough to
correct for numerical drift error. Also decreasing the tolerance will improve the approximation too.
This approximation also allows mc_arc to immediately insert a line segment into the planner
without the initial overhead of computing cos() or sin(). By the time the arc needs to be applied
@ -156,7 +156,7 @@ void mc_arc(float *position, float *target, float *offset, uint8_t axis_0, uint8
*/
// Computes: cos_T = 1 - theta_per_segment^2/2, sin_T = theta_per_segment - theta_per_segment^3/6) in ~52usec
float cos_T = 2 - theta_per_segment*theta_per_segment;
float sin_T = theta_per_segment*0.1666667*(cos_T + 4);
float sin_T = theta_per_segment*0.16666667*(cos_T + 4);
cos_T *= 0.5;
float arc_target[N_AXIS];
@ -164,7 +164,7 @@ void mc_arc(float *position, float *target, float *offset, uint8_t axis_0, uint8
float cos_Ti;
float r_axisi;
uint16_t i;
int8_t count = 0;
uint8_t count = 0;
// Initialize the linear axis
arc_target[axis_linear] = position[axis_linear];