Firmware2/Marlin/src/gcode/motion/G2_G3.cpp

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/**
* Marlin 3D Printer Firmware
* Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
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#include "../../inc/MarlinConfig.h"
#if ENABLED(ARC_SUPPORT)
#include "../gcode.h"
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#include "../../module/motion.h"
#include "../../module/planner.h"
#include "../../module/temperature.h"
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#if ENABLED(DELTA)
#include "../../module/delta.h"
#elif ENABLED(SCARA)
#include "../../module/scara.h"
#endif
#if N_ARC_CORRECTION < 1
#undef N_ARC_CORRECTION
#define N_ARC_CORRECTION 1
#endif
/**
* Plan an arc in 2 dimensions
*
* The arc is approximated by generating many small linear segments.
* The length of each segment is configured in MM_PER_ARC_SEGMENT (Default 1mm)
* Arcs should only be made relatively large (over 5mm), as larger arcs with
* larger segments will tend to be more efficient. Your slicer should have
* options for G2/G3 arc generation. In future these options may be GCode tunable.
*/
void plan_arc(
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const float (&cart)[XYZE], // Destination position
const float (&offset)[2], // Center of rotation relative to current_position
const uint8_t clockwise // Clockwise?
) {
#if ENABLED(CNC_WORKSPACE_PLANES)
AxisEnum p_axis, q_axis, l_axis;
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switch (gcode.workspace_plane) {
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default:
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case GcodeSuite::PLANE_XY: p_axis = X_AXIS; q_axis = Y_AXIS; l_axis = Z_AXIS; break;
case GcodeSuite::PLANE_ZX: p_axis = Z_AXIS; q_axis = X_AXIS; l_axis = Y_AXIS; break;
case GcodeSuite::PLANE_YZ: p_axis = Y_AXIS; q_axis = Z_AXIS; l_axis = X_AXIS; break;
}
#else
constexpr AxisEnum p_axis = X_AXIS, q_axis = Y_AXIS, l_axis = Z_AXIS;
#endif
// Radius vector from center to current location
float r_P = -offset[0], r_Q = -offset[1];
const float radius = HYPOT(r_P, r_Q),
center_P = current_position[p_axis] - r_P,
center_Q = current_position[q_axis] - r_Q,
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rt_X = cart[p_axis] - center_P,
rt_Y = cart[q_axis] - center_Q,
linear_travel = cart[l_axis] - current_position[l_axis],
extruder_travel = cart[E_AXIS] - current_position[E_AXIS];
// CCW angle of rotation between position and target from the circle center. Only one atan2() trig computation required.
float angular_travel = ATAN2(r_P * rt_Y - r_Q * rt_X, r_P * rt_X + r_Q * rt_Y);
if (angular_travel < 0) angular_travel += RADIANS(360);
if (clockwise) angular_travel -= RADIANS(360);
// Make a circle if the angular rotation is 0 and the target is current position
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if (angular_travel == 0 && current_position[p_axis] == cart[p_axis] && current_position[q_axis] == cart[q_axis])
angular_travel = RADIANS(360);
const float flat_mm = radius * angular_travel,
mm_of_travel = linear_travel ? HYPOT(flat_mm, linear_travel) : flat_mm;
if (mm_of_travel < 0.001) return;
uint16_t segments = FLOOR(mm_of_travel / (MM_PER_ARC_SEGMENT));
if (segments == 0) segments = 1;
/**
* Vector rotation by transformation matrix: r is the original vector, r_T is the rotated vector,
* and phi is the angle of rotation. Based on the solution approach by Jens Geisler.
* r_T = [cos(phi) -sin(phi);
* sin(phi) cos(phi)] * r ;
*
* For arc generation, the center of the circle is the axis of rotation and the radius vector is
* defined from the circle center to the initial position. Each line segment is formed by successive
* vector rotations. This requires only two cos() and sin() computations to form the rotation
* matrix for the duration of the entire arc. Error may accumulate from numerical round-off, since
* all double numbers are single precision on the Arduino. (True double precision will not have
* round off issues for CNC applications.) Single precision error can accumulate to be greater than
* tool precision in some cases. Therefore, arc path correction is implemented.
*
* Small angle approximation may be used to reduce computation overhead further. This approximation
* holds for everything, but very small circles and large MM_PER_ARC_SEGMENT values. In other words,
* theta_per_segment would need to be greater than 0.1 rad and N_ARC_CORRECTION would need to be large
* to cause an appreciable drift error. N_ARC_CORRECTION~=25 is more than small enough to correct for
* numerical drift error. N_ARC_CORRECTION may be on the order a hundred(s) before error becomes an
* issue for CNC machines with the single precision Arduino calculations.
*
* This approximation also allows plan_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
* a correction, the planner should have caught up to the lag caused by the initial plan_arc overhead.
* This is important when there are successive arc motions.
*/
// Vector rotation matrix values
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float raw[XYZE];
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 - 0.5 * sq(theta_per_segment); // Small angle approximation
// Initialize the linear axis
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raw[l_axis] = current_position[l_axis];
// Initialize the extruder axis
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raw[E_AXIS] = current_position[E_AXIS];
const float fr_mm_s = MMS_SCALED(feedrate_mm_s);
millis_t next_idle_ms = millis() + 200UL;
#if N_ARC_CORRECTION > 1
int8_t arc_recalc_count = N_ARC_CORRECTION;
#endif
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#if ENABLED(SCARA_FEEDRATE_SCALING)
// SCARA needs to scale the feed rate from mm/s to degrees/s
const float inv_segment_length = 1.0 / (MM_PER_ARC_SEGMENT),
inverse_secs = inv_segment_length * fr_mm_s;
float oldA = stepper.get_axis_position_degrees(A_AXIS),
oldB = stepper.get_axis_position_degrees(B_AXIS);
#endif
for (uint16_t i = 1; i < segments; i++) { // Iterate (segments-1) times
thermalManager.manage_heater();
if (ELAPSED(millis(), next_idle_ms)) {
next_idle_ms = millis() + 200UL;
idle();
}
#if N_ARC_CORRECTION > 1
if (--arc_recalc_count) {
// Apply vector rotation matrix to previous r_P / 1
const float r_new_Y = r_P * sin_T + r_Q * cos_T;
r_P = r_P * cos_T - r_Q * sin_T;
r_Q = r_new_Y;
}
else
#endif
{
#if N_ARC_CORRECTION > 1
arc_recalc_count = N_ARC_CORRECTION;
#endif
// Arc correction to radius vector. Computed only every N_ARC_CORRECTION increments.
// Compute exact location by applying transformation matrix from initial radius vector(=-offset).
// To reduce stuttering, the sin and cos could be computed at different times.
// For now, compute both at the same time.
const float cos_Ti = cos(i * theta_per_segment), sin_Ti = sin(i * theta_per_segment);
r_P = -offset[0] * cos_Ti + offset[1] * sin_Ti;
r_Q = -offset[0] * sin_Ti - offset[1] * cos_Ti;
}
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// Update raw location
raw[p_axis] = center_P + r_P;
raw[q_axis] = center_Q + r_Q;
raw[l_axis] += linear_per_segment;
raw[E_AXIS] += extruder_per_segment;
clamp_to_software_endstops(raw);
#if ENABLED(SCARA_FEEDRATE_SCALING)
// For SCARA scale the feed rate from mm/s to degrees/s.
// i.e., Complete the angular vector in the given time.
inverse_kinematics(raw);
ADJUST_DELTA(raw);
planner.buffer_segment(delta[A_AXIS], delta[B_AXIS], raw[Z_AXIS], raw[E_AXIS], HYPOT(delta[A_AXIS] - oldA, delta[B_AXIS] - oldB) * inverse_secs, active_extruder);
oldA = delta[A_AXIS]; oldB = delta[B_AXIS];
#else
planner.buffer_line_kinematic(raw, fr_mm_s, active_extruder);
#endif
}
// Ensure last segment arrives at target location.
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#if ENABLED(SCARA_FEEDRATE_SCALING)
inverse_kinematics(cart);
ADJUST_DELTA(cart);
planner.buffer_segment(delta[A_AXIS], delta[B_AXIS], cart[Z_AXIS], cart[E_AXIS], HYPOT(delta[A_AXIS] - oldA, delta[B_AXIS] - oldB) * inverse_secs, active_extruder);
#else
planner.buffer_line_kinematic(cart, fr_mm_s, active_extruder);
#endif
// As far as the parser is concerned, the position is now == target. In reality the
// motion control system might still be processing the action and the real tool position
// in any intermediate location.
set_current_from_destination();
} // plan_arc
/**
* G2: Clockwise Arc
* G3: Counterclockwise Arc
*
* This command has two forms: IJ-form and R-form.
*
* - I specifies an X offset. J specifies a Y offset.
* At least one of the IJ parameters is required.
* X and Y can be omitted to do a complete circle.
* The given XY is not error-checked. The arc ends
* based on the angle of the destination.
* Mixing I or J with R will throw an error.
*
* - R specifies the radius. X or Y is required.
* Omitting both X and Y will throw an error.
* X or Y must differ from the current XY.
* Mixing R with I or J will throw an error.
*
* - P specifies the number of full circles to do
* before the specified arc move.
*
* Examples:
*
* G2 I10 ; CW circle centered at X+10
* G3 X20 Y12 R14 ; CCW circle with r=14 ending at X20 Y12
*/
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void GcodeSuite::G2_G3(const bool clockwise) {
if (MOTION_CONDITIONS) {
#if ENABLED(SF_ARC_FIX)
const bool relative_mode_backup = relative_mode;
relative_mode = true;
#endif
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get_destination_from_command();
#if ENABLED(SF_ARC_FIX)
relative_mode = relative_mode_backup;
#endif
float arc_offset[2] = { 0.0, 0.0 };
if (parser.seenval('R')) {
const float r = parser.value_linear_units(),
p1 = current_position[X_AXIS], q1 = current_position[Y_AXIS],
p2 = destination[X_AXIS], q2 = destination[Y_AXIS];
if (r && (p2 != p1 || q2 != q1)) {
const float e = clockwise ^ (r < 0) ? -1 : 1, // clockwise -1/1, counterclockwise 1/-1
dx = p2 - p1, dy = q2 - q1, // X and Y differences
d = HYPOT(dx, dy), // Linear distance between the points
h = SQRT(sq(r) - sq(d * 0.5)), // Distance to the arc pivot-point
mx = (p1 + p2) * 0.5, my = (q1 + q2) * 0.5, // Point between the two points
sx = -dy / d, sy = dx / d, // Slope of the perpendicular bisector
cx = mx + e * h * sx, cy = my + e * h * sy; // Pivot-point of the arc
arc_offset[0] = cx - p1;
arc_offset[1] = cy - q1;
}
}
else {
if (parser.seenval('I')) arc_offset[0] = parser.value_linear_units();
if (parser.seenval('J')) arc_offset[1] = parser.value_linear_units();
}
if (arc_offset[0] || arc_offset[1]) {
#if ENABLED(ARC_P_CIRCLES)
// P indicates number of circles to do
int8_t circles_to_do = parser.byteval('P');
if (!WITHIN(circles_to_do, 0, 100)) {
SERIAL_ERROR_START();
SERIAL_ERRORLNPGM(MSG_ERR_ARC_ARGS);
}
while (circles_to_do--)
plan_arc(current_position, arc_offset, clockwise);
#endif
// Send the arc to the planner
plan_arc(destination, arc_offset, clockwise);
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refresh_cmd_timeout();
}
else {
// Bad arguments
SERIAL_ERROR_START();
SERIAL_ERRORLNPGM(MSG_ERR_ARC_ARGS);
}
}
}
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#endif // ARC_SUPPORT