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
){
213 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();
238 // TODO I'm not sure if the following is safe to do here, or should it go on the block queue?
239 // case 204: // M204 Snnn - set acceleration to nnn, NB only Snnn is currently supported
240 // gcode->mark_as_taken();
241 // if (gcode->has_letter('S'))
243 // double acc= gcode->get_value('S') * 60 * 60; // mm/min^2
244 // // enforce minimum
247 // this->kernel->planner->acceleration= acc;
251 case 220: // M220 - speed override percentage
252 gcode
->mark_as_taken();
253 if (gcode
->has_letter('S'))
255 double factor
= gcode
->get_value('S');
256 // enforce minimum 10% speed
259 seconds_per_minute
= factor
* 0.6;
263 case 400: // wait until all moves are done up to this point
264 gcode
->mark_as_taken();
265 this->kernel
->conveyor
->wait_for_empty_queue();
268 case 500: // M500 saves some volatile settings to config override file
269 case 503: // M503 just prints the settings
270 this->arm_solution
->get_steps_per_millimeter(steps
);
271 gcode
->stream
->printf(";Steps per unit:\nM92 X%1.5f Y%1.5f Z%1.5f\n", steps
[0], steps
[1], steps
[2]);
272 gcode
->mark_as_taken();
275 case 665: // M665 set optional arm solution variables based on arm solution
276 gcode
->mark_as_taken();
277 // the parameter args could be any letter so try each one
278 for(char c
='A';c
<='Z';c
++) {
280 bool supported
= arm_solution
->get_optional(c
, &v
); // retrieve current value if supported
282 if(supported
&& gcode
->has_letter(c
)) { // set new value if supported
283 v
= gcode
->get_value(c
);
284 arm_solution
->set_optional(c
, v
);
286 if(supported
) { // print all current values of supported options
287 gcode
->stream
->printf("%c %8.3f ", c
, v
);
288 gcode
->add_nl
= true;
296 if( this->motion_mode
< 0)
300 double target
[3], offset
[3];
301 clear_vector(target
); clear_vector(offset
);
303 memcpy(target
, this->current_position
, sizeof(target
)); //default to last target
305 for(char letter
= 'I'; letter
<= 'K'; letter
++){ if( gcode
->has_letter(letter
) ){ offset
[letter
-'I'] = this->to_millimeters(gcode
->get_value(letter
)); } }
306 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']); } }
308 if( gcode
->has_letter('F') )
310 if( this->motion_mode
== MOTION_MODE_SEEK
)
311 this->seek_rate
= this->to_millimeters( gcode
->get_value('F') ) / 60.0;
313 this->feed_rate
= this->to_millimeters( gcode
->get_value('F') ) / 60.0;
316 //Perform any physical actions
317 switch( next_action
){
318 case NEXT_ACTION_DEFAULT
:
319 switch(this->motion_mode
){
320 case MOTION_MODE_CANCEL
: break;
321 case MOTION_MODE_SEEK
: this->append_line(gcode
, target
, this->seek_rate
); break;
322 case MOTION_MODE_LINEAR
: this->append_line(gcode
, target
, this->feed_rate
); break;
323 case MOTION_MODE_CW_ARC
: case MOTION_MODE_CCW_ARC
: this->compute_arc(gcode
, offset
, target
); break;
328 // As far as the parser is concerned, the position is now == target. In reality the
329 // motion control system might still be processing the action and the real tool position
330 // in any intermediate location.
331 memcpy(this->current_position
, target
, sizeof(double)*3); // this->position[] = target[];
335 // We received a new gcode, and one of the functions
336 // determined the distance for that given gcode. So now we can attach this gcode to the right block
338 void Robot::distance_in_gcode_is_known(Gcode
* gcode
){
340 //If the queue is empty, execute immediatly, otherwise attach to the last added block
341 if( this->kernel
->conveyor
->queue
.size() == 0 ){
342 this->kernel
->call_event(ON_GCODE_EXECUTE
, gcode
);
344 Block
* block
= this->kernel
->conveyor
->queue
.get_ref( this->kernel
->conveyor
->queue
.size() - 1 );
345 block
->append_gcode(gcode
);
350 // Reset the position for all axes ( used in homing and G92 stuff )
351 void Robot::reset_axis_position(double position
, int axis
) {
352 this->last_milestone
[axis
] = this->current_position
[axis
] = position
;
353 this->arm_solution
->millimeters_to_steps(this->current_position
, this->kernel
->planner
->position
);
357 // Convert target from millimeters to steps, and append this to the planner
358 void Robot::append_milestone( double target
[], double rate
){
359 int steps
[3]; //Holds the result of the conversion
361 // We use an arm solution object so exotic arm solutions can be used and neatly abstracted
362 this->arm_solution
->millimeters_to_steps( target
, steps
);
365 for(int axis
=X_AXIS
;axis
<=Z_AXIS
;axis
++){deltas
[axis
]=target
[axis
]-this->last_milestone
[axis
];}
367 // Compute how long this move moves, so we can attach it to the block for later use
368 double millimeters_of_travel
= sqrt( pow( deltas
[X_AXIS
], 2 ) + pow( deltas
[Y_AXIS
], 2 ) + pow( deltas
[Z_AXIS
], 2 ) );
370 // Do not move faster than the configured limits
371 for(int axis
=X_AXIS
;axis
<=Z_AXIS
;axis
++){
372 if( this->max_speeds
[axis
] > 0 ){
373 double axis_speed
= ( fabs(deltas
[axis
]) / ( millimeters_of_travel
/ rate
)) * seconds_per_minute
;
374 if( axis_speed
> this->max_speeds
[axis
] ){
375 rate
= rate
* ( this->max_speeds
[axis
] / axis_speed
);
380 // Append the block to the planner
381 this->kernel
->planner
->append_block( steps
, rate
* seconds_per_minute
, millimeters_of_travel
, deltas
);
383 // Update the last_milestone to the current target for the next time we use last_milestone
384 memcpy(this->last_milestone
, target
, sizeof(double)*3); // this->last_milestone[] = target[];
388 // Append a move to the queue ( cutting it into segments if needed )
389 void Robot::append_line(Gcode
* gcode
, double target
[], double rate
){
391 // Find out the distance for this gcode
392 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 ) );
394 // We ignore non-moves ( for example, extruder moves are not XYZ moves )
395 if( gcode
->millimeters_of_travel
< 0.0001 ){ return; }
397 // Mark the gcode as having a known distance
398 this->distance_in_gcode_is_known( gcode
);
400 // We cut the line into smaller segments. This is not usefull in a cartesian robot, but necessary for robots with rotational axes.
401 // In cartesian robot, a high "mm_per_line_segment" setting will prevent waste.
402 // 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
405 if(this->delta_segments_per_second
> 1.0) {
406 // enabled if set to something > 1, it is set to 0.0 by default
407 // segment based on current speed and requested segments per second
408 // the faster the travel speed the fewer segments needed
409 // NOTE rate is mm/sec and we take into account any speed override
410 float seconds
= 60.0/seconds_per_minute
* gcode
->millimeters_of_travel
/ rate
;
411 segments
= max(1, ceil(this->delta_segments_per_second
* seconds
));
412 // TODO if we are only moving in Z on a delta we don't really need to segment at all
415 if(this->mm_per_line_segment
== 0.0){
416 segments
= 1; // don't split it up
418 segments
= ceil( gcode
->millimeters_of_travel
/ this->mm_per_line_segment
);
422 // A vector to keep track of the endpoint of each segment
423 double temp_target
[3];
425 memcpy( temp_target
, this->current_position
, sizeof(double)*3); // temp_target[] = this->current_position[];
428 for( int i
=0; i
<segments
-1; i
++ ){
429 for(int axis
=X_AXIS
; axis
<= Z_AXIS
; axis
++ ){ temp_target
[axis
] += ( target
[axis
]-this->current_position
[axis
] )/segments
; }
430 // Append the end of this segment to the queue
431 this->append_milestone(temp_target
, rate
);
434 // Append the end of this full move to the queue
435 this->append_milestone(target
, rate
);
439 // Append an arc to the queue ( cutting it into segments as needed )
440 void Robot::append_arc(Gcode
* gcode
, double target
[], double offset
[], double radius
, bool is_clockwise
){
443 double center_axis0
= this->current_position
[this->plane_axis_0
] + offset
[this->plane_axis_0
];
444 double center_axis1
= this->current_position
[this->plane_axis_1
] + offset
[this->plane_axis_1
];
445 double linear_travel
= target
[this->plane_axis_2
] - this->current_position
[this->plane_axis_2
];
446 double r_axis0
= -offset
[this->plane_axis_0
]; // Radius vector from center to current location
447 double r_axis1
= -offset
[this->plane_axis_1
];
448 double rt_axis0
= target
[this->plane_axis_0
] - center_axis0
;
449 double rt_axis1
= target
[this->plane_axis_1
] - center_axis1
;
451 // CCW angle between position and target from circle center. Only one atan2() trig computation required.
452 double angular_travel
= atan2(r_axis0
*rt_axis1
-r_axis1
*rt_axis0
, r_axis0
*rt_axis0
+r_axis1
*rt_axis1
);
453 if (angular_travel
< 0) { angular_travel
+= 2*M_PI
; }
454 if (is_clockwise
) { angular_travel
-= 2*M_PI
; }
456 // Find the distance for this gcode
457 gcode
->millimeters_of_travel
= hypot(angular_travel
*radius
, fabs(linear_travel
));
459 // We don't care about non-XYZ moves ( for example the extruder produces some of those )
460 if( gcode
->millimeters_of_travel
< 0.0001 ){ return; }
462 // Mark the gcode as having a known distance
463 this->distance_in_gcode_is_known( gcode
);
465 // Figure out how many segments for this gcode
466 uint16_t segments
= floor(gcode
->millimeters_of_travel
/this->mm_per_arc_segment
);
468 double theta_per_segment
= angular_travel
/segments
;
469 double linear_per_segment
= linear_travel
/segments
;
471 /* Vector rotation by transformation matrix: r is the original vector, r_T is the rotated vector,
472 and phi is the angle of rotation. Based on the solution approach by Jens Geisler.
473 r_T = [cos(phi) -sin(phi);
474 sin(phi) cos(phi] * r ;
475 For arc generation, the center of the circle is the axis of rotation and the radius vector is
476 defined from the circle center to the initial position. Each line segment is formed by successive
477 vector rotations. This requires only two cos() and sin() computations to form the rotation
478 matrix for the duration of the entire arc. Error may accumulate from numerical round-off, since
479 all double numbers are single precision on the Arduino. (True double precision will not have
480 round off issues for CNC applications.) Single precision error can accumulate to be greater than
481 tool precision in some cases. Therefore, arc path correction is implemented.
483 Small angle approximation may be used to reduce computation overhead further. This approximation
484 holds for everything, but very small circles and large mm_per_arc_segment values. In other words,
485 theta_per_segment would need to be greater than 0.1 rad and N_ARC_CORRECTION would need to be large
486 to cause an appreciable drift error. N_ARC_CORRECTION~=25 is more than small enough to correct for
487 numerical drift error. N_ARC_CORRECTION may be on the order a hundred(s) before error becomes an
488 issue for CNC machines with the single precision Arduino calculations.
489 This approximation also allows mc_arc to immediately insert a line segment into the planner
490 without the initial overhead of computing cos() or sin(). By the time the arc needs to be applied
491 a correction, the planner should have caught up to the lag caused by the initial mc_arc overhead.
492 This is important when there are successive arc motions.
494 // Vector rotation matrix values
495 double cos_T
= 1-0.5*theta_per_segment
*theta_per_segment
; // Small angle approximation
496 double sin_T
= theta_per_segment
;
498 double arc_target
[3];
505 // Initialize the linear axis
506 arc_target
[this->plane_axis_2
] = this->current_position
[this->plane_axis_2
];
508 for (i
= 1; i
<segments
; i
++) { // Increment (segments-1)
510 if (count
< this->arc_correction
) {
511 // Apply vector rotation matrix
512 r_axisi
= r_axis0
*sin_T
+ r_axis1
*cos_T
;
513 r_axis0
= r_axis0
*cos_T
- r_axis1
*sin_T
;
517 // Arc correction to radius vector. Computed only every N_ARC_CORRECTION increments.
518 // Compute exact location by applying transformation matrix from initial radius vector(=-offset).
519 cos_Ti
= cos(i
*theta_per_segment
);
520 sin_Ti
= sin(i
*theta_per_segment
);
521 r_axis0
= -offset
[this->plane_axis_0
]*cos_Ti
+ offset
[this->plane_axis_1
]*sin_Ti
;
522 r_axis1
= -offset
[this->plane_axis_0
]*sin_Ti
- offset
[this->plane_axis_1
]*cos_Ti
;
526 // Update arc_target location
527 arc_target
[this->plane_axis_0
] = center_axis0
+ r_axis0
;
528 arc_target
[this->plane_axis_1
] = center_axis1
+ r_axis1
;
529 arc_target
[this->plane_axis_2
] += linear_per_segment
;
531 // Append this segment to the queue
532 this->append_milestone(arc_target
, this->feed_rate
);
536 // Ensure last segment arrives at target location.
537 this->append_milestone(target
, this->feed_rate
);
540 // Do the math for an arc and add it to the queue
541 void Robot::compute_arc(Gcode
* gcode
, double offset
[], double target
[]){
544 double radius
= hypot(offset
[this->plane_axis_0
], offset
[this->plane_axis_1
]);
546 // Set clockwise/counter-clockwise sign for mc_arc computations
547 bool is_clockwise
= false;
548 if( this->motion_mode
== MOTION_MODE_CW_ARC
){ is_clockwise
= true; }
551 this->append_arc(gcode
, target
, offset
, radius
, is_clockwise
);
556 double Robot::theta(double x
, double y
){
557 double t
= atan(x
/fabs(y
));
558 if (y
>0) {return(t
);} else {if (t
>0){return(M_PI
-t
);} else {return(-M_PI
-t
);}}
561 void Robot::select_plane(uint8_t axis_0
, uint8_t axis_1
, uint8_t axis_2
){
562 this->plane_axis_0
= axis_0
;
563 this->plane_axis_1
= axis_1
;
564 this->plane_axis_2
= axis_2
;