2 This file is part of Smoothie (http://smoothieware.org/). The motion control part is heavily based on Grbl (https://github.com/simen/grbl) with additions from Sungeun K. Jeon (https://github.com/chamnit/grbl)
3 Smoothie 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.
4 Smoothie 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.
5 You should have received a copy of the GNU General Public License along with Smoothie. If not, see <http://www.gnu.org/licenses/>.
8 #include "libs/Module.h"
9 #include "libs/Kernel.h"
16 #include "libs/nuts_bolts.h"
18 #include "libs/StepperMotor.h"
19 #include "../communication/utils/Gcode.h"
20 #include "PublicDataRequest.h"
21 #include "arm_solutions/BaseSolution.h"
22 #include "arm_solutions/CartesianSolution.h"
23 #include "arm_solutions/RotatableCartesianSolution.h"
24 #include "arm_solutions/RostockSolution.h"
25 #include "arm_solutions/JohannKosselSolution.h"
26 #include "arm_solutions/HBotSolution.h"
28 #define default_seek_rate_checksum CHECKSUM("default_seek_rate")
29 #define default_feed_rate_checksum CHECKSUM("default_feed_rate")
30 #define mm_per_line_segment_checksum CHECKSUM("mm_per_line_segment")
31 #define delta_segments_per_second_checksum CHECKSUM("delta_segments_per_second")
32 #define mm_per_arc_segment_checksum CHECKSUM("mm_per_arc_segment")
33 #define arc_correction_checksum CHECKSUM("arc_correction")
34 #define x_axis_max_speed_checksum CHECKSUM("x_axis_max_speed")
35 #define y_axis_max_speed_checksum CHECKSUM("y_axis_max_speed")
36 #define z_axis_max_speed_checksum CHECKSUM("z_axis_max_speed")
39 #define arm_solution_checksum CHECKSUM("arm_solution")
40 #define cartesian_checksum CHECKSUM("cartesian")
41 #define rotatable_cartesian_checksum CHECKSUM("rotatable_cartesian")
42 #define rostock_checksum CHECKSUM("rostock")
43 #define delta_checksum CHECKSUM("delta")
44 #define hbot_checksum CHECKSUM("hbot")
45 #define corexy_checksum CHECKSUM("corexy")
46 #define kossel_checksum CHECKSUM("kossel")
48 // The Robot converts GCodes into actual movements, and then adds them to the Planner, which passes them to the Conveyor so they can be added to the queue
49 // It takes care of cutting arcs into segments, same thing for line that are too long
50 #define max(a,b) (((a) > (b)) ? (a) : (b))
53 this->inch_mode
= false;
54 this->absolute_mode
= true;
55 this->motion_mode
= MOTION_MODE_SEEK
;
56 this->select_plane(X_AXIS
, Y_AXIS
, Z_AXIS
);
57 clear_vector(this->current_position
);
58 clear_vector(this->last_milestone
);
59 this->arm_solution
= NULL
;
60 seconds_per_minute
= 60.0;
63 //Called when the module has just been loaded
64 void Robot::on_module_loaded() {
65 register_for_event(ON_CONFIG_RELOAD
);
66 this->register_for_event(ON_GCODE_RECEIVED
);
67 this->register_for_event(ON_GET_PUBLIC_DATA
);
68 this->register_for_event(ON_SET_PUBLIC_DATA
);
71 this->on_config_reload(this);
73 // Make our 3 StepperMotors
74 this->alpha_stepper_motor
= this->kernel
->step_ticker
->add_stepper_motor( new StepperMotor(&alpha_step_pin
,&alpha_dir_pin
,&alpha_en_pin
) );
75 this->beta_stepper_motor
= this->kernel
->step_ticker
->add_stepper_motor( new StepperMotor(&beta_step_pin
, &beta_dir_pin
, &beta_en_pin
) );
76 this->gamma_stepper_motor
= this->kernel
->step_ticker
->add_stepper_motor( new StepperMotor(&gamma_step_pin
,&gamma_dir_pin
,&gamma_en_pin
) );
80 void Robot::on_config_reload(void* argument
){
82 // Arm solutions are used to convert positions in millimeters into position in steps for each stepper motor.
83 // While for a cartesian arm solution, this is a simple multiplication, in other, less simple cases, there is some serious math to be done.
84 // To make adding those solution easier, they have their own, separate object.
85 // Here we read the config to find out which arm solution to use
86 if (this->arm_solution
) delete this->arm_solution
;
87 int solution_checksum
= get_checksum(this->kernel
->config
->value(arm_solution_checksum
)->by_default("cartesian")->as_string());
88 // Note checksums are not const expressions when in debug mode, so don't use switch
89 if(solution_checksum
== hbot_checksum
|| solution_checksum
== corexy_checksum
) {
90 this->arm_solution
= new HBotSolution(this->kernel
->config
);
92 }else if(solution_checksum
== rostock_checksum
) {
93 this->arm_solution
= new RostockSolution(this->kernel
->config
);
95 }else if(solution_checksum
== kossel_checksum
) {
96 this->arm_solution
= new JohannKosselSolution(this->kernel
->config
);
98 }else if(solution_checksum
== delta_checksum
) {
99 // place holder for now
100 this->arm_solution
= new RostockSolution(this->kernel
->config
);
102 }else if(solution_checksum
== rotatable_cartesian_checksum
) {
103 this->arm_solution
= new RotatableCartesianSolution(this->kernel
->config
);
105 }else if(solution_checksum
== cartesian_checksum
) {
106 this->arm_solution
= new CartesianSolution(this->kernel
->config
);
109 this->arm_solution
= new CartesianSolution(this->kernel
->config
);
113 this->feed_rate
= this->kernel
->config
->value(default_feed_rate_checksum
)->by_default(100 )->as_number() / 60;
114 this->seek_rate
= this->kernel
->config
->value(default_seek_rate_checksum
)->by_default(100 )->as_number() / 60;
115 this->mm_per_line_segment
= this->kernel
->config
->value(mm_per_line_segment_checksum
)->by_default(0.0 )->as_number();
116 this->delta_segments_per_second
= this->kernel
->config
->value(delta_segments_per_second_checksum
)->by_default(0.0 )->as_number();
117 this->mm_per_arc_segment
= this->kernel
->config
->value(mm_per_arc_segment_checksum
)->by_default(0.5 )->as_number();
118 this->arc_correction
= this->kernel
->config
->value(arc_correction_checksum
)->by_default(5 )->as_number();
119 this->max_speeds
[X_AXIS
] = this->kernel
->config
->value(x_axis_max_speed_checksum
)->by_default(60000 )->as_number();
120 this->max_speeds
[Y_AXIS
] = this->kernel
->config
->value(y_axis_max_speed_checksum
)->by_default(60000 )->as_number();
121 this->max_speeds
[Z_AXIS
] = this->kernel
->config
->value(z_axis_max_speed_checksum
)->by_default(300 )->as_number();
122 this->alpha_step_pin
.from_string( this->kernel
->config
->value(alpha_step_pin_checksum
)->by_default("2.0" )->as_string())->as_output();
123 this->alpha_dir_pin
.from_string( this->kernel
->config
->value(alpha_dir_pin_checksum
)->by_default("0.5" )->as_string())->as_output();
124 this->alpha_en_pin
.from_string( this->kernel
->config
->value(alpha_en_pin_checksum
)->by_default("0.4" )->as_string())->as_output();
125 this->beta_step_pin
.from_string( this->kernel
->config
->value(beta_step_pin_checksum
)->by_default("2.1" )->as_string())->as_output();
126 this->gamma_step_pin
.from_string( this->kernel
->config
->value(gamma_step_pin_checksum
)->by_default("2.2" )->as_string())->as_output();
127 this->gamma_dir_pin
.from_string( this->kernel
->config
->value(gamma_dir_pin_checksum
)->by_default("0.20" )->as_string())->as_output();
128 this->gamma_en_pin
.from_string( this->kernel
->config
->value(gamma_en_pin_checksum
)->by_default("0.19" )->as_string())->as_output();
129 this->beta_dir_pin
.from_string( this->kernel
->config
->value(beta_dir_pin_checksum
)->by_default("0.11" )->as_string())->as_output();
130 this->beta_en_pin
.from_string( this->kernel
->config
->value(beta_en_pin_checksum
)->by_default("0.10" )->as_string())->as_output();
134 void Robot::on_get_public_data(void* argument
){
135 PublicDataRequest
* pdr
= static_cast<PublicDataRequest
*>(argument
);
137 if(!pdr
->starts_with(robot_checksum
)) return;
139 if(pdr
->second_element_is(speed_override_percent_checksum
)) {
140 static double return_data
;
141 return_data
= 100*this->seconds_per_minute
/60;
142 pdr
->set_data_ptr(&return_data
);
145 }else if(pdr
->second_element_is(current_position_checksum
)) {
146 static double return_data
[3];
147 return_data
[0]= from_millimeters(this->current_position
[0]);
148 return_data
[1]= from_millimeters(this->current_position
[1]);
149 return_data
[2]= from_millimeters(this->current_position
[2]);
151 pdr
->set_data_ptr(&return_data
);
156 void Robot::on_set_public_data(void* argument
){
157 PublicDataRequest
* pdr
= static_cast<PublicDataRequest
*>(argument
);
159 if(!pdr
->starts_with(robot_checksum
)) return;
161 if(pdr
->second_element_is(speed_override_percent_checksum
)) {
162 // NOTE do not use this while printing!
163 double t
= *static_cast<double*>(pdr
->get_data_ptr());
164 // enforce minimum 10% speed
165 if (t
< 10.0) t
= 10.0;
167 this->seconds_per_minute
= t
* 0.6;
172 //A GCode has been received
173 //See if the current Gcode line has some orders for us
174 void Robot::on_gcode_received(void * argument
){
175 Gcode
* gcode
= static_cast<Gcode
*>(argument
);
177 //Temp variables, constant properties are stored in the object
178 uint8_t next_action
= NEXT_ACTION_DEFAULT
;
179 this->motion_mode
= -1;
181 //G-letter Gcodes are mostly what the Robot module is interrested in, other modules also catch the gcode event and do stuff accordingly
184 case 0: this->motion_mode
= MOTION_MODE_SEEK
; gcode
->mark_as_taken(); break;
185 case 1: this->motion_mode
= MOTION_MODE_LINEAR
; gcode
->mark_as_taken(); break;
186 case 2: this->motion_mode
= MOTION_MODE_CW_ARC
; gcode
->mark_as_taken(); break;
187 case 3: this->motion_mode
= MOTION_MODE_CCW_ARC
; gcode
->mark_as_taken(); break;
188 case 17: this->select_plane(X_AXIS
, Y_AXIS
, Z_AXIS
); gcode
->mark_as_taken(); break;
189 case 18: this->select_plane(X_AXIS
, Z_AXIS
, Y_AXIS
); gcode
->mark_as_taken(); break;
190 case 19: this->select_plane(Y_AXIS
, Z_AXIS
, X_AXIS
); gcode
->mark_as_taken(); break;
191 case 20: this->inch_mode
= true; gcode
->mark_as_taken(); break;
192 case 21: this->inch_mode
= false; gcode
->mark_as_taken(); break;
193 case 90: this->absolute_mode
= true; gcode
->mark_as_taken(); break;
194 case 91: this->absolute_mode
= false; gcode
->mark_as_taken(); break;
196 if(gcode
->get_num_args() == 0){
197 clear_vector(this->last_milestone
);
199 for (char letter
= 'X'; letter
<= 'Z'; letter
++){
200 if ( gcode
->has_letter(letter
) )
201 this->last_milestone
[letter
-'X'] = this->to_millimeters(gcode
->get_value(letter
));
204 memcpy(this->current_position
, this->last_milestone
, sizeof(double)*3); // current_position[] = last_milestone[];
205 this->arm_solution
->millimeters_to_steps(this->current_position
, this->kernel
->planner
->position
);
206 gcode
->mark_as_taken();
207 return; // TODO: Wait until queue empty
210 }else if( gcode
->has_m
){
212 case 92: // M92 - set steps per mm
214 this->arm_solution
->get_steps_per_millimeter(steps
);
215 if (gcode
->has_letter('X'))
216 steps
[0] = this->to_millimeters(gcode
->get_value('X'));
217 if (gcode
->has_letter('Y'))
218 steps
[1] = this->to_millimeters(gcode
->get_value('Y'));
219 if (gcode
->has_letter('Z'))
220 steps
[2] = this->to_millimeters(gcode
->get_value('Z'));
221 if (gcode
->has_letter('F'))
222 seconds_per_minute
= gcode
->get_value('F');
223 this->arm_solution
->set_steps_per_millimeter(steps
);
224 // update current position in steps
225 this->arm_solution
->millimeters_to_steps(this->current_position
, this->kernel
->planner
->position
);
226 gcode
->stream
->printf("X:%g Y:%g Z:%g F:%g ", steps
[0], steps
[1], steps
[2], seconds_per_minute
);
227 gcode
->add_nl
= true;
228 gcode
->mark_as_taken();
230 case 114: gcode
->stream
->printf("C: X:%1.3f Y:%1.3f Z:%1.3f ",
231 from_millimeters(this->current_position
[0]),
232 from_millimeters(this->current_position
[1]),
233 from_millimeters(this->current_position
[2]));
234 gcode
->add_nl
= true;
235 gcode
->mark_as_taken();
237 // TODO I'm not sure if the following is safe to do here, or should it go on the block queue?
238 // case 204: // M204 Snnn - set acceleration to nnn, NB only Snnn is currently supported
239 // gcode->mark_as_taken();
240 // if (gcode->has_letter('S'))
242 // double acc= gcode->get_value('S') * 60 * 60; // mm/min^2
243 // // enforce minimum
246 // this->kernel->planner->acceleration= acc;
250 case 220: // M220 - speed override percentage
251 gcode
->mark_as_taken();
252 if (gcode
->has_letter('S'))
254 double factor
= gcode
->get_value('S');
255 // enforce minimum 10% speed
258 seconds_per_minute
= factor
* 0.6;
262 case 400: // wait until all moves are done up to this point
263 gcode
->mark_as_taken();
264 this->kernel
->conveyor
->wait_for_empty_queue();
267 case 665: // M665 set optional arm solution variables based on arm solution
268 gcode
->mark_as_taken();
269 // the parameter args could be any letter so try each one
270 for(char c
='A';c
<='Z';c
++) {
272 bool supported
= arm_solution
->get_optional(c
, &v
); // retrieve current value if supported
274 if(supported
&& gcode
->has_letter(c
)) { // set new value if supported
275 v
= gcode
->get_value(c
);
276 arm_solution
->set_optional(c
, v
);
278 if(supported
) { // print all current values of supported options
279 gcode
->stream
->printf("%c %8.3f ", c
, v
);
280 gcode
->add_nl
= true;
288 if( this->motion_mode
< 0)
292 double target
[3], offset
[3];
293 clear_vector(target
); clear_vector(offset
);
295 memcpy(target
, this->current_position
, sizeof(target
)); //default to last target
297 for(char letter
= 'I'; letter
<= 'K'; letter
++){ if( gcode
->has_letter(letter
) ){ offset
[letter
-'I'] = this->to_millimeters(gcode
->get_value(letter
)); } }
298 for(char letter
= 'X'; letter
<= 'Z'; letter
++){ if( gcode
->has_letter(letter
) ){ target
[letter
-'X'] = this->to_millimeters(gcode
->get_value(letter
)) + ( this->absolute_mode
? 0 : target
[letter
-'X']); } }
300 if( gcode
->has_letter('F') )
302 if( this->motion_mode
== MOTION_MODE_SEEK
)
303 this->seek_rate
= this->to_millimeters( gcode
->get_value('F') ) / 60.0;
305 this->feed_rate
= this->to_millimeters( gcode
->get_value('F') ) / 60.0;
308 //Perform any physical actions
309 switch( next_action
){
310 case NEXT_ACTION_DEFAULT
:
311 switch(this->motion_mode
){
312 case MOTION_MODE_CANCEL
: break;
313 case MOTION_MODE_SEEK
: this->append_line(gcode
, target
, this->seek_rate
); break;
314 case MOTION_MODE_LINEAR
: this->append_line(gcode
, target
, this->feed_rate
); break;
315 case MOTION_MODE_CW_ARC
: case MOTION_MODE_CCW_ARC
: this->compute_arc(gcode
, offset
, target
); break;
320 // As far as the parser is concerned, the position is now == target. In reality the
321 // motion control system might still be processing the action and the real tool position
322 // in any intermediate location.
323 memcpy(this->current_position
, target
, sizeof(double)*3); // this->position[] = target[];
327 // We received a new gcode, and one of the functions
328 // determined the distance for that given gcode. So now we can attach this gcode to the right block
330 void Robot::distance_in_gcode_is_known(Gcode
* gcode
){
332 //If the queue is empty, execute immediatly, otherwise attach to the last added block
333 if( this->kernel
->conveyor
->queue
.size() == 0 ){
334 this->kernel
->call_event(ON_GCODE_EXECUTE
, gcode
);
336 Block
* block
= this->kernel
->conveyor
->queue
.get_ref( this->kernel
->conveyor
->queue
.size() - 1 );
337 block
->append_gcode(gcode
);
342 // Reset the position for all axes ( used in homing and G92 stuff )
343 void Robot::reset_axis_position(double position
, int axis
) {
344 this->last_milestone
[axis
] = this->current_position
[axis
] = position
;
345 this->arm_solution
->millimeters_to_steps(this->current_position
, this->kernel
->planner
->position
);
349 // Convert target from millimeters to steps, and append this to the planner
350 void Robot::append_milestone( double target
[], double rate
){
351 int steps
[3]; //Holds the result of the conversion
353 // We use an arm solution object so exotic arm solutions can be used and neatly abstracted
354 this->arm_solution
->millimeters_to_steps( target
, steps
);
357 for(int axis
=X_AXIS
;axis
<=Z_AXIS
;axis
++){deltas
[axis
]=target
[axis
]-this->last_milestone
[axis
];}
359 // Compute how long this move moves, so we can attach it to the block for later use
360 double millimeters_of_travel
= sqrt( pow( deltas
[X_AXIS
], 2 ) + pow( deltas
[Y_AXIS
], 2 ) + pow( deltas
[Z_AXIS
], 2 ) );
362 // Do not move faster than the configured limits
363 for(int axis
=X_AXIS
;axis
<=Z_AXIS
;axis
++){
364 if( this->max_speeds
[axis
] > 0 ){
365 double axis_speed
= ( fabs(deltas
[axis
]) / ( millimeters_of_travel
/ rate
)) * seconds_per_minute
;
366 if( axis_speed
> this->max_speeds
[axis
] ){
367 rate
= rate
* ( this->max_speeds
[axis
] / axis_speed
);
372 // Append the block to the planner
373 this->kernel
->planner
->append_block( steps
, rate
* seconds_per_minute
, millimeters_of_travel
, deltas
);
375 // Update the last_milestone to the current target for the next time we use last_milestone
376 memcpy(this->last_milestone
, target
, sizeof(double)*3); // this->last_milestone[] = target[];
380 // Append a move to the queue ( cutting it into segments if needed )
381 void Robot::append_line(Gcode
* gcode
, double target
[], double rate
){
383 // Find out the distance for this gcode
384 gcode
->millimeters_of_travel
= sqrt( pow( target
[X_AXIS
]-this->current_position
[X_AXIS
], 2 ) + pow( target
[Y_AXIS
]-this->current_position
[Y_AXIS
], 2 ) + pow( target
[Z_AXIS
]-this->current_position
[Z_AXIS
], 2 ) );
386 // We ignore non-moves ( for example, extruder moves are not XYZ moves )
387 if( gcode
->millimeters_of_travel
< 0.0001 ){ return; }
389 // Mark the gcode as having a known distance
390 this->distance_in_gcode_is_known( gcode
);
392 // We cut the line into smaller segments. This is not usefull in a cartesian robot, but necessary for robots with rotational axes.
393 // In cartesian robot, a high "mm_per_line_segment" setting will prevent waste.
394 // In delta robots either mm_per_line_segment can be used OR delta_segments_per_second The latter is more efficient and avoids splitting fast long lines into very small segments, like initial z move to 0, it is what Johanns Marlin delta port does
397 if(this->delta_segments_per_second
> 1.0) {
398 // enabled if set to something > 1, it is set to 0.0 by default
399 // segment based on current speed and requested segments per second
400 // the faster the travel speed the fewer segments needed
401 // NOTE rate is mm/sec and we take into account any speed override
402 float seconds
= 60.0/seconds_per_minute
* gcode
->millimeters_of_travel
/ rate
;
403 segments
= max(1, ceil(this->delta_segments_per_second
* seconds
));
404 // TODO if we are only moving in Z on a delta we don't really need to segment at all
407 if(this->mm_per_line_segment
== 0.0){
408 segments
= 1; // don't split it up
410 segments
= ceil( gcode
->millimeters_of_travel
/ this->mm_per_line_segment
);
414 // A vector to keep track of the endpoint of each segment
415 double temp_target
[3];
417 memcpy( temp_target
, this->current_position
, sizeof(double)*3); // temp_target[] = this->current_position[];
420 for( int i
=0; i
<segments
-1; i
++ ){
421 for(int axis
=X_AXIS
; axis
<= Z_AXIS
; axis
++ ){ temp_target
[axis
] += ( target
[axis
]-this->current_position
[axis
] )/segments
; }
422 // Append the end of this segment to the queue
423 this->append_milestone(temp_target
, rate
);
426 // Append the end of this full move to the queue
427 this->append_milestone(target
, rate
);
431 // Append an arc to the queue ( cutting it into segments as needed )
432 void Robot::append_arc(Gcode
* gcode
, double target
[], double offset
[], double radius
, bool is_clockwise
){
435 double center_axis0
= this->current_position
[this->plane_axis_0
] + offset
[this->plane_axis_0
];
436 double center_axis1
= this->current_position
[this->plane_axis_1
] + offset
[this->plane_axis_1
];
437 double linear_travel
= target
[this->plane_axis_2
] - this->current_position
[this->plane_axis_2
];
438 double r_axis0
= -offset
[this->plane_axis_0
]; // Radius vector from center to current location
439 double r_axis1
= -offset
[this->plane_axis_1
];
440 double rt_axis0
= target
[this->plane_axis_0
] - center_axis0
;
441 double rt_axis1
= target
[this->plane_axis_1
] - center_axis1
;
443 // CCW angle between position and target from circle center. Only one atan2() trig computation required.
444 double angular_travel
= atan2(r_axis0
*rt_axis1
-r_axis1
*rt_axis0
, r_axis0
*rt_axis0
+r_axis1
*rt_axis1
);
445 if (angular_travel
< 0) { angular_travel
+= 2*M_PI
; }
446 if (is_clockwise
) { angular_travel
-= 2*M_PI
; }
448 // Find the distance for this gcode
449 gcode
->millimeters_of_travel
= hypot(angular_travel
*radius
, fabs(linear_travel
));
451 // We don't care about non-XYZ moves ( for example the extruder produces some of those )
452 if( gcode
->millimeters_of_travel
< 0.0001 ){ return; }
454 // Mark the gcode as having a known distance
455 this->distance_in_gcode_is_known( gcode
);
457 // Figure out how many segments for this gcode
458 uint16_t segments
= floor(gcode
->millimeters_of_travel
/this->mm_per_arc_segment
);
460 double theta_per_segment
= angular_travel
/segments
;
461 double linear_per_segment
= linear_travel
/segments
;
463 /* Vector rotation by transformation matrix: r is the original vector, r_T is the rotated vector,
464 and phi is the angle of rotation. Based on the solution approach by Jens Geisler.
465 r_T = [cos(phi) -sin(phi);
466 sin(phi) cos(phi] * r ;
467 For arc generation, the center of the circle is the axis of rotation and the radius vector is
468 defined from the circle center to the initial position. Each line segment is formed by successive
469 vector rotations. This requires only two cos() and sin() computations to form the rotation
470 matrix for the duration of the entire arc. Error may accumulate from numerical round-off, since
471 all double numbers are single precision on the Arduino. (True double precision will not have
472 round off issues for CNC applications.) Single precision error can accumulate to be greater than
473 tool precision in some cases. Therefore, arc path correction is implemented.
475 Small angle approximation may be used to reduce computation overhead further. This approximation
476 holds for everything, but very small circles and large mm_per_arc_segment values. In other words,
477 theta_per_segment would need to be greater than 0.1 rad and N_ARC_CORRECTION would need to be large
478 to cause an appreciable drift error. N_ARC_CORRECTION~=25 is more than small enough to correct for
479 numerical drift error. N_ARC_CORRECTION may be on the order a hundred(s) before error becomes an
480 issue for CNC machines with the single precision Arduino calculations.
481 This approximation also allows mc_arc to immediately insert a line segment into the planner
482 without the initial overhead of computing cos() or sin(). By the time the arc needs to be applied
483 a correction, the planner should have caught up to the lag caused by the initial mc_arc overhead.
484 This is important when there are successive arc motions.
486 // Vector rotation matrix values
487 double cos_T
= 1-0.5*theta_per_segment
*theta_per_segment
; // Small angle approximation
488 double sin_T
= theta_per_segment
;
490 double arc_target
[3];
497 // Initialize the linear axis
498 arc_target
[this->plane_axis_2
] = this->current_position
[this->plane_axis_2
];
500 for (i
= 1; i
<segments
; i
++) { // Increment (segments-1)
502 if (count
< this->arc_correction
) {
503 // Apply vector rotation matrix
504 r_axisi
= r_axis0
*sin_T
+ r_axis1
*cos_T
;
505 r_axis0
= r_axis0
*cos_T
- r_axis1
*sin_T
;
509 // Arc correction to radius vector. Computed only every N_ARC_CORRECTION increments.
510 // Compute exact location by applying transformation matrix from initial radius vector(=-offset).
511 cos_Ti
= cos(i
*theta_per_segment
);
512 sin_Ti
= sin(i
*theta_per_segment
);
513 r_axis0
= -offset
[this->plane_axis_0
]*cos_Ti
+ offset
[this->plane_axis_1
]*sin_Ti
;
514 r_axis1
= -offset
[this->plane_axis_0
]*sin_Ti
- offset
[this->plane_axis_1
]*cos_Ti
;
518 // Update arc_target location
519 arc_target
[this->plane_axis_0
] = center_axis0
+ r_axis0
;
520 arc_target
[this->plane_axis_1
] = center_axis1
+ r_axis1
;
521 arc_target
[this->plane_axis_2
] += linear_per_segment
;
523 // Append this segment to the queue
524 this->append_milestone(arc_target
, this->feed_rate
);
528 // Ensure last segment arrives at target location.
529 this->append_milestone(target
, this->feed_rate
);
532 // Do the math for an arc and add it to the queue
533 void Robot::compute_arc(Gcode
* gcode
, double offset
[], double target
[]){
536 double radius
= hypot(offset
[this->plane_axis_0
], offset
[this->plane_axis_1
]);
538 // Set clockwise/counter-clockwise sign for mc_arc computations
539 bool is_clockwise
= false;
540 if( this->motion_mode
== MOTION_MODE_CW_ARC
){ is_clockwise
= true; }
543 this->append_arc(gcode
, target
, offset
, radius
, is_clockwise
);
548 double Robot::theta(double x
, double y
){
549 double t
= atan(x
/fabs(y
));
550 if (y
>0) {return(t
);} else {if (t
>0){return(M_PI
-t
);} else {return(-M_PI
-t
);}}
553 void Robot::select_plane(uint8_t axis_0
, uint8_t axis_1
, uint8_t axis_2
){
554 this->plane_axis_0
= axis_0
;
555 this->plane_axis_1
= axis_1
;
556 this->plane_axis_2
= axis_2
;