From 815c8d2b5562115932783c9b3b93372df157f30b Mon Sep 17 00:00:00 2001
From: Eyal <109809+eyal0@users.noreply.github.com>
Date: Sat, 30 May 2020 23:26:15 -0600
Subject: [PATCH] Improve G2 / G3 motion accuracy (#18144)
---
Marlin/src/gcode/motion/G2_G3.cpp | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/Marlin/src/gcode/motion/G2_G3.cpp b/Marlin/src/gcode/motion/G2_G3.cpp
index 91923121c58..5255db23b1e 100644
--- a/Marlin/src/gcode/motion/G2_G3.cpp
+++ b/Marlin/src/gcode/motion/G2_G3.cpp
@@ -117,8 +117,8 @@ void plan_arc(
uint16_t segments = FLOOR(mm_of_travel / seg_length);
if (segments < min_segments) { // Too few segments?
segments = min_segments; // More segments
- seg_length = mm_of_travel / segments; // but also shorter
}
+ seg_length = mm_of_travel / segments;
/**
* Vector rotation by transformation matrix: r is the original vector, r_T is the rotated vector,
@@ -151,8 +151,9 @@ void plan_arc(
const float theta_per_segment = angular_travel / segments,
linear_per_segment = linear_travel / segments,
extruder_per_segment = extruder_travel / segments,
- sin_T = theta_per_segment,
- cos_T = 1 - 0.5f * sq(theta_per_segment); // Small angle approximation
+ sq_theta_per_segment = sq(theta_per_segment),
+ sin_T = theta_per_segment - sq_theta_per_segment*theta_per_segment/6,
+ cos_T = 1 - 0.5f * sq_theta_per_segment; // Small angle approximation
// Initialize the linear axis
raw[l_axis] = current_position[l_axis];
@@ -218,7 +219,7 @@ void plan_arc(
planner.apply_leveling(raw);
#endif
- if (!planner.buffer_line(raw, scaled_fr_mm_s, active_extruder, seg_length
+ if (!planner.buffer_line(raw, scaled_fr_mm_s, active_extruder, 0
#if ENABLED(SCARA_FEEDRATE_SCALING)
, inv_duration
#endif