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
= THEKERNEL
->step_ticker
->add_stepper_motor( new StepperMotor(&alpha_step_pin
,&alpha_dir_pin
,&alpha_en_pin
) );
75 this->beta_stepper_motor
= THEKERNEL
->step_ticker
->add_stepper_motor( new StepperMotor(&beta_step_pin
, &beta_dir_pin
, &beta_en_pin
) );
76 this->gamma_stepper_motor
= THEKERNEL
->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(THEKERNEL
->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(THEKERNEL
->config
);
92 }else if(solution_checksum
== rostock_checksum
) {
93 this->arm_solution
= new RostockSolution(THEKERNEL
->config
);
95 }else if(solution_checksum
== kossel_checksum
) {
96 this->arm_solution
= new JohannKosselSolution(THEKERNEL
->config
);
98 }else if(solution_checksum
== delta_checksum
) {
99 // place holder for now
100 this->arm_solution
= new RostockSolution(THEKERNEL
->config
);
102 }else if(solution_checksum
== rotatable_cartesian_checksum
) {
103 this->arm_solution
= new RotatableCartesianSolution(THEKERNEL
->config
);
105 }else if(solution_checksum
== cartesian_checksum
) {
106 this->arm_solution
= new CartesianSolution(THEKERNEL
->config
);
109 this->arm_solution
= new CartesianSolution(THEKERNEL
->config
);
113 this->feed_rate
= THEKERNEL
->config
->value(default_feed_rate_checksum
)->by_default(100 )->as_number() / 60;
114 this->seek_rate
= THEKERNEL
->config
->value(default_seek_rate_checksum
)->by_default(100 )->as_number() / 60;
115 this->mm_per_line_segment
= THEKERNEL
->config
->value(mm_per_line_segment_checksum
)->by_default(0.0f
)->as_number();
116 this->delta_segments_per_second
= THEKERNEL
->config
->value(delta_segments_per_second_checksum
)->by_default(0.0f
)->as_number();
117 this->mm_per_arc_segment
= THEKERNEL
->config
->value(mm_per_arc_segment_checksum
)->by_default(0.5f
)->as_number();
118 this->arc_correction
= THEKERNEL
->config
->value(arc_correction_checksum
)->by_default(5 )->as_number();
119 this->max_speeds
[X_AXIS
] = THEKERNEL
->config
->value(x_axis_max_speed_checksum
)->by_default(60000 )->as_number();
120 this->max_speeds
[Y_AXIS
] = THEKERNEL
->config
->value(y_axis_max_speed_checksum
)->by_default(60000 )->as_number();
121 this->max_speeds
[Z_AXIS
] = THEKERNEL
->config
->value(z_axis_max_speed_checksum
)->by_default(300 )->as_number();
122 this->alpha_step_pin
.from_string( THEKERNEL
->config
->value(alpha_step_pin_checksum
)->by_default("2.0" )->as_string())->as_output();
123 this->alpha_dir_pin
.from_string( THEKERNEL
->config
->value(alpha_dir_pin_checksum
)->by_default("0.5" )->as_string())->as_output();
124 this->alpha_en_pin
.from_string( THEKERNEL
->config
->value(alpha_en_pin_checksum
)->by_default("0.4" )->as_string())->as_output();
125 this->beta_step_pin
.from_string( THEKERNEL
->config
->value(beta_step_pin_checksum
)->by_default("2.1" )->as_string())->as_output();
126 this->gamma_step_pin
.from_string( THEKERNEL
->config
->value(gamma_step_pin_checksum
)->by_default("2.2" )->as_string())->as_output();
127 this->gamma_dir_pin
.from_string( THEKERNEL
->config
->value(gamma_dir_pin_checksum
)->by_default("0.20" )->as_string())->as_output();
128 this->gamma_en_pin
.from_string( THEKERNEL
->config
->value(gamma_en_pin_checksum
)->by_default("0.19" )->as_string())->as_output();
129 this->beta_dir_pin
.from_string( THEKERNEL
->config
->value(beta_dir_pin_checksum
)->by_default("0.11" )->as_string())->as_output();
130 this->beta_en_pin
.from_string( THEKERNEL
->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 float 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 float 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 float t
= *static_cast<float*>(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(float)*3); // current_position[] = last_milestone[];
205 this->arm_solution
->millimeters_to_steps(this->current_position
, THEKERNEL
->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
, THEKERNEL
->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 float acc
= gcode
->get_value('S') * 60 * 60; // mm/min^2
247 THEKERNEL
->planner
->acceleration
= acc
;
251 case 205: // M205 Xnnn - set junction deviation
252 gcode
->mark_as_taken();
253 if (gcode
->has_letter('X'))
255 float jd
= gcode
->get_value('X');
259 THEKERNEL
->planner
->junction_deviation
= jd
;
263 case 220: // M220 - speed override percentage
264 gcode
->mark_as_taken();
265 if (gcode
->has_letter('S'))
267 float factor
= gcode
->get_value('S');
268 // enforce minimum 10% speed
271 seconds_per_minute
= factor
* 0.6;
275 case 400: // wait until all moves are done up to this point
276 gcode
->mark_as_taken();
277 THEKERNEL
->conveyor
->wait_for_empty_queue();
280 case 500: // M500 saves some volatile settings to config override file
281 case 503: // M503 just prints the settings
282 this->arm_solution
->get_steps_per_millimeter(steps
);
283 gcode
->stream
->printf(";Steps per unit:\nM92 X%1.5f Y%1.5f Z%1.5f\n", steps
[0], steps
[1], steps
[2]);
284 gcode
->stream
->printf(";Acceleration mm/sec^2:\nM204 S%1.5f\n", THEKERNEL
->planner
->acceleration
/3600);
285 gcode
->stream
->printf(";Junction Deviation:\nM205 X%1.5f\n", THEKERNEL
->planner
->junction_deviation
);
286 gcode
->mark_as_taken();
289 case 665: // M665 set optional arm solution variables based on arm solution
290 gcode
->mark_as_taken();
291 // the parameter args could be any letter so try each one
292 for(char c
='A';c
<='Z';c
++) {
294 bool supported
= arm_solution
->get_optional(c
, &v
); // retrieve current value if supported
296 if(supported
&& gcode
->has_letter(c
)) { // set new value if supported
297 v
= gcode
->get_value(c
);
298 arm_solution
->set_optional(c
, v
);
300 if(supported
) { // print all current values of supported options
301 gcode
->stream
->printf("%c %8.3f ", c
, v
);
302 gcode
->add_nl
= true;
310 if( this->motion_mode
< 0)
314 float target
[3], offset
[3];
315 clear_vector(target
); clear_vector(offset
);
317 memcpy(target
, this->current_position
, sizeof(target
)); //default to last target
319 for(char letter
= 'I'; letter
<= 'K'; letter
++){ if( gcode
->has_letter(letter
) ){ offset
[letter
-'I'] = this->to_millimeters(gcode
->get_value(letter
)); } }
320 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']); } }
322 if( gcode
->has_letter('F') )
324 if( this->motion_mode
== MOTION_MODE_SEEK
)
325 this->seek_rate
= this->to_millimeters( gcode
->get_value('F') ) / 60.0;
327 this->feed_rate
= this->to_millimeters( gcode
->get_value('F') ) / 60.0;
330 //Perform any physical actions
331 switch( next_action
){
332 case NEXT_ACTION_DEFAULT
:
333 switch(this->motion_mode
){
334 case MOTION_MODE_CANCEL
: break;
335 case MOTION_MODE_SEEK
: this->append_line(gcode
, target
, this->seek_rate
); break;
336 case MOTION_MODE_LINEAR
: this->append_line(gcode
, target
, this->feed_rate
); break;
337 case MOTION_MODE_CW_ARC
: case MOTION_MODE_CCW_ARC
: this->compute_arc(gcode
, offset
, target
); break;
342 // As far as the parser is concerned, the position is now == target. In reality the
343 // motion control system might still be processing the action and the real tool position
344 // in any intermediate location.
345 memcpy(this->current_position
, target
, sizeof(float)*3); // this->position[] = target[];
349 // We received a new gcode, and one of the functions
350 // determined the distance for that given gcode. So now we can attach this gcode to the right block
352 void Robot::distance_in_gcode_is_known(Gcode
* gcode
){
354 //If the queue is empty, execute immediatly, otherwise attach to the last added block
355 if( THEKERNEL
->conveyor
->queue
.size() == 0 ){
356 THEKERNEL
->call_event(ON_GCODE_EXECUTE
, gcode
);
358 Block
* block
= THEKERNEL
->conveyor
->queue
.get_ref( THEKERNEL
->conveyor
->queue
.size() - 1 );
359 block
->append_gcode(gcode
);
364 // Reset the position for all axes ( used in homing and G92 stuff )
365 void Robot::reset_axis_position(float position
, int axis
) {
366 this->last_milestone
[axis
] = this->current_position
[axis
] = position
;
367 this->arm_solution
->millimeters_to_steps(this->current_position
, THEKERNEL
->planner
->position
);
371 // Convert target from millimeters to steps, and append this to the planner
372 void Robot::append_milestone( float target
[], float rate
){
373 int steps
[3]; //Holds the result of the conversion
375 // We use an arm solution object so exotic arm solutions can be used and neatly abstracted
376 this->arm_solution
->millimeters_to_steps( target
, steps
);
379 for(int axis
=X_AXIS
;axis
<=Z_AXIS
;axis
++){deltas
[axis
]=target
[axis
]-this->last_milestone
[axis
];}
381 // Compute how long this move moves, so we can attach it to the block for later use
382 float millimeters_of_travel
= sqrtf( pow( deltas
[X_AXIS
], 2 ) + pow( deltas
[Y_AXIS
], 2 ) + pow( deltas
[Z_AXIS
], 2 ) );
384 // Do not move faster than the configured limits
385 for(int axis
=X_AXIS
;axis
<=Z_AXIS
;axis
++){
386 if( this->max_speeds
[axis
] > 0 ){
387 float axis_speed
= ( fabs(deltas
[axis
]) / ( millimeters_of_travel
/ rate
)) * seconds_per_minute
;
388 if( axis_speed
> this->max_speeds
[axis
] ){
389 rate
= rate
* ( this->max_speeds
[axis
] / axis_speed
);
394 // Append the block to the planner
395 THEKERNEL
->planner
->append_block( steps
, rate
* seconds_per_minute
, millimeters_of_travel
, deltas
);
397 // Update the last_milestone to the current target for the next time we use last_milestone
398 memcpy(this->last_milestone
, target
, sizeof(float)*3); // this->last_milestone[] = target[];
402 // Append a move to the queue ( cutting it into segments if needed )
403 void Robot::append_line(Gcode
* gcode
, float target
[], float rate
){
405 // Find out the distance for this gcode
406 gcode
->millimeters_of_travel
= sqrtf( 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 ) );
408 // We ignore non-moves ( for example, extruder moves are not XYZ moves )
409 if( gcode
->millimeters_of_travel
< 0.0001 ){ return; }
411 // Mark the gcode as having a known distance
412 this->distance_in_gcode_is_known( gcode
);
414 // We cut the line into smaller segments. This is not usefull in a cartesian robot, but necessary for robots with rotational axes.
415 // In cartesian robot, a high "mm_per_line_segment" setting will prevent waste.
416 // 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
419 if(this->delta_segments_per_second
> 1.0) {
420 // enabled if set to something > 1, it is set to 0.0 by default
421 // segment based on current speed and requested segments per second
422 // the faster the travel speed the fewer segments needed
423 // NOTE rate is mm/sec and we take into account any speed override
424 float seconds
= 60.0/seconds_per_minute
* gcode
->millimeters_of_travel
/ rate
;
425 segments
= max(1, ceil(this->delta_segments_per_second
* seconds
));
426 // TODO if we are only moving in Z on a delta we don't really need to segment at all
429 if(this->mm_per_line_segment
== 0.0){
430 segments
= 1; // don't split it up
432 segments
= ceil( gcode
->millimeters_of_travel
/ this->mm_per_line_segment
);
436 // A vector to keep track of the endpoint of each segment
437 float temp_target
[3];
439 memcpy( temp_target
, this->current_position
, sizeof(float)*3); // temp_target[] = this->current_position[];
442 for( int i
=0; i
<segments
-1; i
++ ){
443 for(int axis
=X_AXIS
; axis
<= Z_AXIS
; axis
++ ){ temp_target
[axis
] += ( target
[axis
]-this->current_position
[axis
] )/segments
; }
444 // Append the end of this segment to the queue
445 this->append_milestone(temp_target
, rate
);
448 // Append the end of this full move to the queue
449 this->append_milestone(target
, rate
);
453 // Append an arc to the queue ( cutting it into segments as needed )
454 void Robot::append_arc(Gcode
* gcode
, float target
[], float offset
[], float radius
, bool is_clockwise
){
457 float center_axis0
= this->current_position
[this->plane_axis_0
] + offset
[this->plane_axis_0
];
458 float center_axis1
= this->current_position
[this->plane_axis_1
] + offset
[this->plane_axis_1
];
459 float linear_travel
= target
[this->plane_axis_2
] - this->current_position
[this->plane_axis_2
];
460 float r_axis0
= -offset
[this->plane_axis_0
]; // Radius vector from center to current location
461 float r_axis1
= -offset
[this->plane_axis_1
];
462 float rt_axis0
= target
[this->plane_axis_0
] - center_axis0
;
463 float rt_axis1
= target
[this->plane_axis_1
] - center_axis1
;
465 // CCW angle between position and target from circle center. Only one atan2() trig computation required.
466 float angular_travel
= atan2(r_axis0
*rt_axis1
-r_axis1
*rt_axis0
, r_axis0
*rt_axis0
+r_axis1
*rt_axis1
);
467 if (angular_travel
< 0) { angular_travel
+= 2*M_PI
; }
468 if (is_clockwise
) { angular_travel
-= 2*M_PI
; }
470 // Find the distance for this gcode
471 gcode
->millimeters_of_travel
= hypotf(angular_travel
*radius
, fabs(linear_travel
));
473 // We don't care about non-XYZ moves ( for example the extruder produces some of those )
474 if( gcode
->millimeters_of_travel
< 0.0001 ){ return; }
476 // Mark the gcode as having a known distance
477 this->distance_in_gcode_is_known( gcode
);
479 // Figure out how many segments for this gcode
480 uint16_t segments
= floor(gcode
->millimeters_of_travel
/this->mm_per_arc_segment
);
482 float theta_per_segment
= angular_travel
/segments
;
483 float linear_per_segment
= linear_travel
/segments
;
485 /* Vector rotation by transformation matrix: r is the original vector, r_T is the rotated vector,
486 and phi is the angle of rotation. Based on the solution approach by Jens Geisler.
487 r_T = [cos(phi) -sin(phi);
488 sin(phi) cos(phi] * r ;
489 For arc generation, the center of the circle is the axis of rotation and the radius vector is
490 defined from the circle center to the initial position. Each line segment is formed by successive
491 vector rotations. This requires only two cos() and sin() computations to form the rotation
492 matrix for the duration of the entire arc. Error may accumulate from numerical round-off, since
493 all float numbers are single precision on the Arduino. (True float precision will not have
494 round off issues for CNC applications.) Single precision error can accumulate to be greater than
495 tool precision in some cases. Therefore, arc path correction is implemented.
497 Small angle approximation may be used to reduce computation overhead further. This approximation
498 holds for everything, but very small circles and large mm_per_arc_segment values. In other words,
499 theta_per_segment would need to be greater than 0.1 rad and N_ARC_CORRECTION would need to be large
500 to cause an appreciable drift error. N_ARC_CORRECTION~=25 is more than small enough to correct for
501 numerical drift error. N_ARC_CORRECTION may be on the order a hundred(s) before error becomes an
502 issue for CNC machines with the single precision Arduino calculations.
503 This approximation also allows mc_arc to immediately insert a line segment into the planner
504 without the initial overhead of computing cos() or sin(). By the time the arc needs to be applied
505 a correction, the planner should have caught up to the lag caused by the initial mc_arc overhead.
506 This is important when there are successive arc motions.
508 // Vector rotation matrix values
509 float cos_T
= 1-0.5*theta_per_segment
*theta_per_segment
; // Small angle approximation
510 float sin_T
= theta_per_segment
;
519 // Initialize the linear axis
520 arc_target
[this->plane_axis_2
] = this->current_position
[this->plane_axis_2
];
522 for (i
= 1; i
<segments
; i
++) { // Increment (segments-1)
524 if (count
< this->arc_correction
) {
525 // Apply vector rotation matrix
526 r_axisi
= r_axis0
*sin_T
+ r_axis1
*cos_T
;
527 r_axis0
= r_axis0
*cos_T
- r_axis1
*sin_T
;
531 // Arc correction to radius vector. Computed only every N_ARC_CORRECTION increments.
532 // Compute exact location by applying transformation matrix from initial radius vector(=-offset).
533 cos_Ti
= cosf(i
*theta_per_segment
);
534 sin_Ti
= sinf(i
*theta_per_segment
);
535 r_axis0
= -offset
[this->plane_axis_0
]*cos_Ti
+ offset
[this->plane_axis_1
]*sin_Ti
;
536 r_axis1
= -offset
[this->plane_axis_0
]*sin_Ti
- offset
[this->plane_axis_1
]*cos_Ti
;
540 // Update arc_target location
541 arc_target
[this->plane_axis_0
] = center_axis0
+ r_axis0
;
542 arc_target
[this->plane_axis_1
] = center_axis1
+ r_axis1
;
543 arc_target
[this->plane_axis_2
] += linear_per_segment
;
545 // Append this segment to the queue
546 this->append_milestone(arc_target
, this->feed_rate
);
550 // Ensure last segment arrives at target location.
551 this->append_milestone(target
, this->feed_rate
);
554 // Do the math for an arc and add it to the queue
555 void Robot::compute_arc(Gcode
* gcode
, float offset
[], float target
[]){
558 float radius
= hypotf(offset
[this->plane_axis_0
], offset
[this->plane_axis_1
]);
560 // Set clockwise/counter-clockwise sign for mc_arc computations
561 bool is_clockwise
= false;
562 if( this->motion_mode
== MOTION_MODE_CW_ARC
){ is_clockwise
= true; }
565 this->append_arc(gcode
, target
, offset
, radius
, is_clockwise
);
570 float Robot::theta(float x
, float y
){
571 float t
= atanf(x
/fabs(y
));
572 if (y
>0) {return(t
);} else {if (t
>0){return(M_PI
-t
);} else {return(-M_PI
-t
);}}
575 void Robot::select_plane(uint8_t axis_0
, uint8_t axis_1
, uint8_t axis_2
){
576 this->plane_axis_0
= axis_0
;
577 this->plane_axis_1
= axis_1
;
578 this->plane_axis_2
= axis_2
;