// Executes one line of 0-terminated G-Code. The line is assumed to contain only uppercase
// characters and signed floating point values (no whitespace).
uint8_t gc_execute_line(char *line) {
uint8_t char_counter = 0;
char letter;
double value;
double unit_converted_value;
double inverse_feed_rate = -1; // negative inverse_feed_rate means no inverse_feed_rate specified
int radius_mode = false;
uint8_t absolute_override = false; /* 1 = absolute motion for this block only {G53} */
uint8_t next_action = NEXT_ACTION_DEFAULT; /* The action that will be taken by the parsed line */
double target[3], offset[3];
double p = 0, r = 0;
int int_value;
clear_vector(target);
clear_vector(offset);
gc.status_code = STATUS_OK;
// Disregard comments and block delete
if (line[0] == '(') { return(gc.status_code); }
if (line[0] == '/') { char_counter++; } // ignore block delete
// Pass 1: Commands
while(next_statement(&letter, &value, line, &char_counter)) {
int_value = trunc(value);
switch(letter) {
case 'G':
switch(int_value) {
case 0: gc.motion_mode = MOTION_MODE_SEEK; break;
case 1: gc.motion_mode = MOTION_MODE_LINEAR; break;
#ifdef __AVR_ATmega328P__
case 2: gc.motion_mode = MOTION_MODE_CW_ARC; break;
case 3: gc.motion_mode = MOTION_MODE_CCW_ARC; break;
#endif
case 4: next_action = NEXT_ACTION_DWELL; break;
case 17: select_plane(X_AXIS, Y_AXIS, Z_AXIS); break;
case 18: select_plane(X_AXIS, Z_AXIS, Y_AXIS); break;
case 19: select_plane(Y_AXIS, Z_AXIS, X_AXIS); break;
case 20: gc.inches_mode = true; break;
case 21: gc.inches_mode = false; break;
case 28: case 30: next_action = NEXT_ACTION_GO_HOME; break;
case 53: absolute_override = true; break;
case 80: gc.motion_mode = MOTION_MODE_CANCEL; break;
case 90: gc.absolute_mode = true; break;
case 91: gc.absolute_mode = false; break;
case 92: next_action = NEXT_ACTION_SET_COORDINATE_OFFSET; break;
case 93: gc.inverse_feed_rate_mode = true; break;
case 94: gc.inverse_feed_rate_mode = false; break;
default: FAIL(STATUS_UNSUPPORTED_STATEMENT);
}
break;
case 'M':
switch(int_value) {
case 0: case 1: gc.program_flow = PROGRAM_FLOW_PAUSED; break;
case 2: case 30: case 60: gc.program_flow = PROGRAM_FLOW_COMPLETED; break;
case 3: gc.spindle_direction = 1; break;
case 4: gc.spindle_direction = -1; break;
case 5: gc.spindle_direction = 0; break;
default: FAIL(STATUS_UNSUPPORTED_STATEMENT);
}
break;
case 'T': gc.tool = trunc(value); break;
}
if(gc.status_code) { break; }
}
// If there were any errors parsing this line, we will return right away with the bad news
if (gc.status_code) { return(gc.status_code); }
char_counter = 0;
clear_vector(offset);
memcpy(target, gc.position, sizeof(target)); // i.e. target = gc.position
// Pass 2: Parameters
while(next_statement(&letter, &value, line, &char_counter)) {
int_value = trunc(value);
unit_converted_value = to_millimeters(value);
switch(letter) {
case 'F':
if (gc.inverse_feed_rate_mode) {
inverse_feed_rate = unit_converted_value; // seconds per motion for this motion only
} else {
if (gc.motion_mode == MOTION_MODE_SEEK) {
gc.seek_rate = unit_converted_value/60;
} else {
gc.feed_rate = unit_converted_value/60; // millimeters pr second
}
}
break;
case 'I': case 'J': case 'K': offset[letter-'I'] = unit_converted_value; break;
case 'P': p = value; break;
case 'R': r = unit_converted_value; radius_mode = true; break;
case 'S': gc.spindle_speed = value; break;
case 'X': case 'Y': case 'Z':
if (gc.absolute_mode || absolute_override) {
target[letter - 'X'] = unit_converted_value;
} else {
target[letter - 'X'] += unit_converted_value;
}
break;
}
}
// If there were any errors parsing this line, we will return right away with the bad news
if (gc.status_code) { return(gc.status_code); }
// Update spindle state
spindle_run(gc.spindle_direction, gc.spindle_speed);
// Perform any physical actions
switch (next_action) {
case NEXT_ACTION_GO_HOME: mc_go_home(); clear_vector(gc.position); break; // Go home
case NEXT_ACTION_DWELL: mc_dwell(trunc(p*1000)); break; // Dwell
case NEXT_ACTION_SET_COORDINATE_OFFSET: // Coordinate System offset
mc_set_current_position(target[X_AXIS], target[Y_AXIS], target[Z_AXIS]);
break;
case NEXT_ACTION_DEFAULT:
switch (gc.motion_mode) {
case MOTION_MODE_CANCEL: break;
case MOTION_MODE_SEEK:
mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], gc.seek_rate, false);
break;
case MOTION_MODE_LINEAR:
mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS],
(gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode);
break;
#ifdef __AVR_ATmega328P__
case MOTION_MODE_CW_ARC: case MOTION_MODE_CCW_ARC:
if (radius_mode) {
/*
We need to calculate the center of the circle that has the designated radius and passes
through both the current position and the target position. This method calculates the following
set of equations where [x,y] is the vector from current to target position, d == magnitude of
that vector, h == hypotenuse of the triangle formed by the radius of the circle, the distance to
the center of the travel vector. A vector perpendicular to the travel vector [-y,x] is scaled to the
length of h [-y/d*h, x/d*h] and added to the center of the travel vector [x/2,y/2] to form the new point
[i,j] at [x/2-y/d*h, y/2+x/d*h] which will be the center of our arc.
d^2 == x^2 + y^2
h^2 == r^2 - (d/2)^2
i == x/2 - y/d*h
j == y/2 + x/d*h
O <- [i,j]
- |
r - |
- |
- | h
- |
[0,0] -> C -----------------+--------------- T <- [x,y]
| <------ d/2 ---->|
C - Current position
T - Target position
O - center of circle that pass through both C and T
d - distance from C to T
r - designated radius
h - distance from center of CT to O
Expanding the equations:
d -> sqrt(x^2 + y^2)
h -> sqrt(4 * r^2 - x^2 - y^2)/2
i -> (x - (y * sqrt(4 * r^2 - x^2 - y^2)) / sqrt(x^2 + y^2)) / 2
j -> (y + (x * sqrt(4 * r^2 - x^2 - y^2)) / sqrt(x^2 + y^2)) / 2
Which can be written:
i -> (x - (y * sqrt(4 * r^2 - x^2 - y^2))/sqrt(x^2 + y^2))/2
j -> (y + (x * sqrt(4 * r^2 - x^2 - y^2))/sqrt(x^2 + y^2))/2
Which we for size and speed reasons optimize to:
h_x2_div_d = sqrt(4 * r^2 - x^2 - y^2)/sqrt(x^2 + y^2)
i = (x - (y * h_x2_div_d))/2
j = (y + (x * h_x2_div_d))/2
*/
// Calculate the change in position along each selected axis
double x = target[gc.plane_axis_0]-gc.position[gc.plane_axis_0];
double y = target[gc.plane_axis_1]-gc.position[gc.plane_axis_1];
clear_vector(offset);
double h_x2_div_d = -sqrt(4 * r*r - x*x - y*y)/hypot(x,y); // == -(h * 2 / d)
// If r is smaller than d, the arc is now traversing the complex plane beyond the reach of any
// real CNC, and thus - for practical reasons - we will terminate promptly:
if(isnan(h_x2_div_d)) { FAIL(STATUS_FLOATING_POINT_ERROR); return(gc.status_code); }
// Invert the sign of h_x2_div_d if the circle is counter clockwise (see sketch below)
if (gc.motion_mode == MOTION_MODE_CCW_ARC) { h_x2_div_d = -h_x2_div_d; }
/* The counter clockwise circle lies to the left of the target direction. When offset is positive,
the left hand circle will be generated - when it is negative the right hand circle is generated.
T <-- Target position
^
Clockwise circles with this center | Clockwise circles with this center will have
will have > 180 deg of angular travel | < 180 deg of angular travel, which is a good thing!
\ | /
center of arc when h_x2_div_d is positive -> x <----- | -----> x <- center of arc when h_x2_div_d is negative
|
|
C <-- Current position */
// Negative R is g-code-alese for "I want a circle with more than 180 degrees of travel" (go figure!),
// even though it is advised against ever generating such circles in a single line of g-code. By
// inverting the sign of h_x2_div_d the center of the circles is placed on the opposite side of the line of
// travel and thus we get the unadvisably long arcs as prescribed.
if (r < 0) { h_x2_div_d = -h_x2_div_d; }
// Complete the operation by calculating the actual center of the arc
offset[gc.plane_axis_0] = (x-(y*h_x2_div_d))/2;
offset[gc.plane_axis_1] = (y+(x*h_x2_div_d))/2;
}
/*
This segment sets up an clockwise or counterclockwise arc from the current position to the target position around
the center designated by the offset vector. All theta-values measured in radians of deviance from the positive
y-axis.
| <- theta == 0
* * *
* *
* *
* O ----T <- theta_end (e.g. 90 degrees: theta_end == PI/2)
* /
C <- theta_start (e.g. -145 degrees: theta_start == -PI*(3/4))
*/
// calculate the theta (angle) of the current point
double theta_start = theta(-offset[gc.plane_axis_0], -offset[gc.plane_axis_1]);
// calculate the theta (angle) of the target point
double theta_end = theta(target[gc.plane_axis_0] - offset[gc.plane_axis_0] - gc.position[gc.plane_axis_0],
target[gc.plane_axis_1] - offset[gc.plane_axis_1] - gc.position[gc.plane_axis_1]);
// ensure that the difference is positive so that we have clockwise travel
if (theta_end < theta_start) { theta_end += 2*M_PI; }
double angular_travel = theta_end-theta_start;
// Invert angular motion if the g-code wanted a counterclockwise arc
if (gc.motion_mode == MOTION_MODE_CCW_ARC) {
angular_travel = angular_travel-2*M_PI;
}
// Find the radius
double radius = hypot(offset[gc.plane_axis_0], offset[gc.plane_axis_1]);
// Calculate the motion along the depth axis of the helix
double depth = target[gc.plane_axis_2]-gc.position[gc.plane_axis_2];
// Trace the arc
mc_arc(theta_start, angular_travel, radius, depth, gc.plane_axis_0, gc.plane_axis_1, gc.plane_axis_2,
(gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode,
gc.position);
// Finish off with a line to make sure we arrive exactly where we think we are
mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS],
(gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode);
break;
#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.
memcpy(gc.position, target, sizeof(double)*3); // gc.position[] = target[];
return(gc.status_code);
}
void jogging()
// Tests jog port pins and moves steppers
{
uint8_t jog_bits, jog_bits_old, out_bits0, jog_exit, last_sys_state;
uint8_t i, limit_state, spindle_bits;
uint32_t dest_step_rate, step_rate, step_delay; // Step delay after pulse
switch (sys.state) {
case STATE_CYCLE: case STATE_HOMING: case STATE_INIT:
LED_PORT |= (1<<LED_ERROR_BIT);
return;
case STATE_ALARM: case STATE_QUEUED:
LED_PORT &= ~(1<<LED_ERROR_BIT); break;
default:
LED_PORT |= (1<<LED_ERROR_BIT);
}
last_sys_state = sys.state;
spindle_bits = (~PINOUT_PIN) & (1<<PIN_SPIN_TOGGLE); // active low
if (spindle_bits) {
if (spindle_status) {
// gc.spindle_direction = 0;
spindle_run(0);
}
else {
// gc.spindle_direction = 1; // also update gcode spindle status
spindle_run(1);
}
spindle_btn_release();
delay_ms(20);
}
jog_bits = (~JOGSW_PIN) & JOGSW_MASK; // active low
if (!jog_bits) { return; } // nothing pressed
// At least one jog/joystick switch is active
if (jog_bits & (1<<JOG_ZERO)) { // Zero-Button gedrückt
jog_btn_release();
sys.state = last_sys_state;
if (bit_isfalse(PINOUT_PIN,bit(PIN_RESET))) { // RESET und zusätzlich ZERO gedrückt: Homing
if (bit_istrue(settings.flags,BITFLAG_HOMING_ENABLE)) {
// Only perform homing if Grbl is idle or lost.
if ( sys.state==STATE_IDLE || sys.state==STATE_ALARM ) {
mc_go_home();
if (!sys.abort) { protocol_execute_startup(); } // Execute startup scripts after successful homing.
}
}
} else { // Zero current work position
sys_sync_current_position();
// gc.coord_system[i] Current work coordinate system (G54+). Stores offset from absolute machine
// position in mm. Loaded from EEPROM when called.
// gc.coord_offset[i] Retains the G92 coordinate offset (work coordinates) relative to
// machine zero in mm. Non-persistent. Cleared upon reset and boot.
for (i=0; i<=2; i++) { // Axes indices are consistent, so loop may be used.
gc.coord_offset[i] = gc.position[i] - gc.coord_system[i];
}
// Z-Achse um bestimmten Betrag zurückziehen
mc_line(gc.position[X_AXIS], gc.position[Y_AXIS], gc.position[Z_AXIS]
+ (settings.z_zero_pulloff * settings.z_scale), settings.default_seek_rate, false);
plan_synchronize(); // Make sure the motion completes
gc.position[Z_AXIS] = gc.position[Z_AXIS] - (settings.z_zero_gauge * settings.z_scale);
gc.coord_offset[Z_AXIS] = gc.position[Z_AXIS] - gc.coord_system[Z_AXIS];
// The gcode parser position circumvented by the pull-off maneuver, so sync position vectors.
// Sets the planner position vector to current steps. Called by the system abort routine.
// Sets g-code parser position in mm. Input in steps. Called by the system abort and hard
sys_sync_current_position(); // Syncs all internal position vectors to the current system position.
}
return;
}
ADCSRA = ADCSRA_init | (1<<ADIF); //0x93, clear ADIF
uint8_t reverse_flag = 0;
uint8_t out_bits = 0;
uint8_t jog_select = 0;
out_bits0 = (0) ^ (settings.invert_mask);
ADCSRA = ADCSRA_init | (1<<ADIF); //0x93, clear ADIF
ADCSRA = ADCSRA_init | (1<<ADSC); //0xC3; start conversion
sys.state = STATE_JOG;
// check for reverse switches
if (jog_bits & (1<<JOGREV_X_BIT)) { // X reverse switch on
out_bits0 ^= (1<<X_DIRECTION_BIT);
out_bits = out_bits0 ^ (1<<X_STEP_BIT);
reverse_flag = 1;
}
if (jog_bits & (1<<JOGREV_Y_BIT)) { // Y reverse switch on
out_bits0 ^= (1<<Y_DIRECTION_BIT);
out_bits = out_bits0 ^ (1<<Y_STEP_BIT);
reverse_flag = 1;
jog_select = 1;
}
if (jog_bits & (1<<JOGREV_Z_BIT)) { // Z reverse switch on
out_bits0 ^= (1<<Z_DIRECTION_BIT);
out_bits = out_bits0 ^ (1<<Z_STEP_BIT);
reverse_flag = 1;
jog_select = 2;
}
// check for forward switches
if (jog_bits & (1<<JOGFWD_X_BIT)) { // X forward switch on
out_bits = out_bits0 ^ (1<<X_STEP_BIT);
}
if (jog_bits & (1<<JOGFWD_Y_BIT)) { // Y forward switch on
out_bits = out_bits0 ^ (1<<Y_STEP_BIT);
jog_select = 1;
}
if (jog_bits & (1<<JOGFWD_Z_BIT)) { // Z forward switch on
out_bits = out_bits0 ^ (1<<Z_STEP_BIT);
jog_select = 2;
}
dest_step_rate = ADCH; // set initial dest_step_rate according to analog input
dest_step_rate = (dest_step_rate * JOG_SPEED_FAC) + JOG_MIN_SPEED;
step_rate = JOG_MIN_SPEED; // set initial step rate
jog_exit = 0;
while (!(ADCSRA && (1<<ADIF))) {} // warte bis ADIF-Bit gesetzt
ADCSRA = ADCSRA_init; // exit conversion
st_wake_up();
// prepare direction with small delay, direction settle time
STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK) | (out_bits0 & STEPPING_MASK);
delay_us(10);
jog_bits_old = jog_bits;
i = 0; // now index for sending position data
for(;;) { // repeat until button/joystick released
// report_realtime_status(); // benötigt viel Zeit!
ADCSRA = ADCSRA_init | (1<<ADIF); //0x93, clear ADIF
// Get limit pin state
#ifdef LIMIT_SWITCHES_ACTIVE_HIGH
// When in an active-high switch configuration
limit_state = LIMIT_PIN;
#else
limit_state = LIMIT_PIN ^ LIMIT_MASK;
#endif
if ((limit_state & LIMIT_MASK) && reverse_flag) { jog_exit = 1; } // immediate stop
jog_bits = (~JOGSW_PIN) & JOGSW_MASK; // active low
if (jog_bits == jog_bits_old) { // nothing changed
if (step_rate < (dest_step_rate - 5)) { // Hysterese für A/D-Wandlung
step_rate += JOG_RAMP; // accellerate
}
if (step_rate > (dest_step_rate + 5)) { // Hysterese für A/D-Wandlung
step_rate -= JOG_RAMP; // brake
}
}
else {
if (step_rate > (JOG_MIN_SPEED*2)) { // switch change happened, fast brake to complete stop
step_rate = ((step_rate * 99) / 100) - 10;
}
else { jog_exit = 1; } // finished to stop and exit
}
// stop and exit if done
if (jog_exit || (sys.execute & EXEC_RESET)) {
st_go_idle();
sys.state = last_sys_state;
sys_sync_current_position();
return;
}
// update position registers
if (reverse_flag) {
sys.position[jog_select]--;
}
else {
sys.position[jog_select]++;
}
ADCSRA = ADCSRA_init | (1<<ADSC); //0xC3; start ADC conversion
// Both direction and step pins appropriately inverted and set. Perform one step
STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK) | (out_bits & STEPPING_MASK);
delay_us(settings.pulse_microseconds);
STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK) | (out_bits0 & STEPPING_MASK);
step_delay = (1000000/step_rate) - settings.pulse_microseconds - 100; // 100 = fester Wert für Schleifenzeit
if (sys.execute & EXEC_STATUS_REPORT) { // status report requested, print short msg only
printPgmString(PSTR("Jog\r\n"));
sys.execute = 0;
}
delay_us(step_delay);
#ifdef JOG_SPI_PRESENT
send_spi_position(i); // bei jedem Durchlauf nur eine Achse übertragen
i++;
if (i>2) {i=0;}
#endif
while (!(ADCSRA && (1<<ADIF))) {} // warte ggf. bis ADIF-Bit gesetzt
ADCSRA = ADCSRA_init; // exit conversion
dest_step_rate = ADCH; // set next dest_step_rate according to analog input
dest_step_rate = (dest_step_rate * JOG_SPEED_FAC) + JOG_MIN_SPEED;
}
}
// Executes one line of 0-terminated G-Code. The line is assumed to contain only uppercase
// characters and signed floating point values (no whitespace). Comments and block delete
// characters have been removed.
uint8_t gc_execute_line(char *line) {
uint8_t char_counter = 0;
char letter;
double value;
double unit_converted_value;
double inverse_feed_rate = -1; // negative inverse_feed_rate means no inverse_feed_rate specified
uint8_t radius_mode = false;
uint8_t absolute_override = false; /* 1 = absolute motion for this block only {G53} */
uint8_t next_action = NEXT_ACTION_DEFAULT; /* The action that will be taken by the parsed line */
double target[3], offset[3];
double p = 0, r = 0;
int int_value;
gc.status_code = STATUS_OK;
// Pass 1: Commands
while(next_statement(&letter, &value, line, &char_counter)) {
int_value = trunc(value);
switch(letter) {
case 'G':
switch(int_value) {
case 0: gc.motion_mode = MOTION_MODE_SEEK; break;
case 1: gc.motion_mode = MOTION_MODE_LINEAR; break;
case 2: gc.motion_mode = MOTION_MODE_CW_ARC; break;
case 3: gc.motion_mode = MOTION_MODE_CCW_ARC; break;
case 4: next_action = NEXT_ACTION_DWELL; break;
case 17: select_plane(X_AXIS, Y_AXIS, Z_AXIS); break;
case 18: select_plane(X_AXIS, Z_AXIS, Y_AXIS); break;
case 19: select_plane(Y_AXIS, Z_AXIS, X_AXIS); break;
case 20: gc.inches_mode = true; break;
case 21: gc.inches_mode = false; break;
case 28: case 30: next_action = NEXT_ACTION_GO_HOME; break;
case 53: absolute_override = true; break;
case 80: gc.motion_mode = MOTION_MODE_CANCEL; break;
case 90: gc.absolute_mode = true; break;
case 91: gc.absolute_mode = false; break;
case 92: next_action = NEXT_ACTION_SET_COORDINATE_OFFSET; break;
case 93: gc.inverse_feed_rate_mode = true; break;
case 94: gc.inverse_feed_rate_mode = false; break;
default: FAIL(STATUS_UNSUPPORTED_STATEMENT);
}
break;
case 'M':
switch(int_value) {
case 0: case 1: gc.program_flow = PROGRAM_FLOW_PAUSED; break;
case 2: case 30: case 60: gc.program_flow = PROGRAM_FLOW_COMPLETED; break;
case 3: gc.laser_enable = 1; break;
case 4: gc.laser_enable = 1; break;
case 5: gc.laser_enable = 0; break;
case 112: next_action = NEXT_ACTION_CANCEL; break;
default: FAIL(STATUS_UNSUPPORTED_STATEMENT);
}
break;
case 'T': gc.tool = trunc(value); break;
}
if(gc.status_code) { break; }
}
// If there were any errors parsing this line, we will return right away with the bad news
if (gc.status_code) { return(gc.status_code); }
char_counter = 0;
clear_vector(target);
clear_vector(offset);
memcpy(target, gc.position, sizeof(target)); // i.e. target = gc.position
// Pass 2: Parameters
while(next_statement(&letter, &value, line, &char_counter)) {
int_value = trunc(value);
unit_converted_value = to_millimeters(value);
switch(letter) {
case 'F':
if (unit_converted_value <= 0) { FAIL(STATUS_BAD_NUMBER_FORMAT); } // Must be greater than zero
if (gc.inverse_feed_rate_mode) {
inverse_feed_rate = unit_converted_value; // seconds per motion for this motion only
} else {
if (gc.motion_mode == MOTION_MODE_SEEK) {
gc.seek_rate = unit_converted_value;
} else {
gc.feed_rate = unit_converted_value; // millimeters per minute
}
}
break;
case 'I': case 'J': case 'K': offset[letter-'I'] = unit_converted_value; break;
case 'P': p = value; break;
case 'R': r = unit_converted_value; radius_mode = true; break;
case 'S': gc.nominal_laser_intensity = value; break;
case 'X': case 'Y': case 'Z':
if (gc.absolute_mode || absolute_override) {
target[letter - 'X'] = unit_converted_value;
} else {
target[letter - 'X'] += unit_converted_value;
}
break;
}
}
// If there were any errors parsing this line, we will return right away with the bad news
if (gc.status_code) { return(gc.status_code); }
// Perform any physical actions
switch (next_action) {
case NEXT_ACTION_GO_HOME: mc_go_home(); clear_vector(gc.position); break;
case NEXT_ACTION_DWELL: mc_dwell(p); break;
case NEXT_ACTION_SET_COORDINATE_OFFSET:
mc_set_current_position(target[X_AXIS], target[Y_AXIS], target[Z_AXIS]);
break;
case NEXT_ACTION_CANCEL:
//mc_emergency_stop();
// captain, we have a new target!
//st_get_position(&gc.position[X_AXIS], &gc.position[Y_AXIS], &gc.position[Z_AXIS]);
//mc_set_current_position(gc.position[X_AXIS], gc.position[Y_AXIS], gc.position[Z_AXIS]);
mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], gc.seek_rate, false, LASER_OFF);
//return; // totally bail
break;
case NEXT_ACTION_DEFAULT:
switch (gc.motion_mode) {
case MOTION_MODE_CANCEL: break;
case MOTION_MODE_SEEK:
mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], gc.seek_rate, false, LASER_OFF);
break;
case MOTION_MODE_LINEAR:
mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS],
(gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode,
gc.nominal_laser_intensity);
break;
case MOTION_MODE_CW_ARC: case MOTION_MODE_CCW_ARC:
if (radius_mode) {
/*
We need to calculate the center of the circle that has the designated radius and passes
through both the current position and the target position. This method calculates the following
set of equations where [x,y] is the vector from current to target position, d == magnitude of
that vector, h == hypotenuse of the triangle formed by the radius of the circle, the distance to
the center of the travel vector. A vector perpendicular to the travel vector [-y,x] is scaled to the
length of h [-y/d*h, x/d*h] and added to the center of the travel vector [x/2,y/2] to form the new point
[i,j] at [x/2-y/d*h, y/2+x/d*h] which will be the center of our arc.
d^2 == x^2 + y^2
h^2 == r^2 - (d/2)^2
i == x/2 - y/d*h
j == y/2 + x/d*h
O <- [i,j]
- |
r - |
- |
- | h
- |
[0,0] -> C -----------------+--------------- T <- [x,y]
| <------ d/2 ---->|
C - Current position
T - Target position
O - center of circle that pass through both C and T
d - distance from C to T
r - designated radius
h - distance from center of CT to O
Expanding the equations:
d -> sqrt(x^2 + y^2)
h -> sqrt(4 * r^2 - x^2 - y^2)/2
i -> (x - (y * sqrt(4 * r^2 - x^2 - y^2)) / sqrt(x^2 + y^2)) / 2
j -> (y + (x * sqrt(4 * r^2 - x^2 - y^2)) / sqrt(x^2 + y^2)) / 2
Which can be written:
i -> (x - (y * sqrt(4 * r^2 - x^2 - y^2))/sqrt(x^2 + y^2))/2
j -> (y + (x * sqrt(4 * r^2 - x^2 - y^2))/sqrt(x^2 + y^2))/2
Which we for size and speed reasons optimize to:
h_x2_div_d = sqrt(4 * r^2 - x^2 - y^2)/sqrt(x^2 + y^2)
i = (x - (y * h_x2_div_d))/2
j = (y + (x * h_x2_div_d))/2
*/
// Calculate the change in position along each selected axis
double x = target[gc.plane_axis_0]-gc.position[gc.plane_axis_0];
double y = target[gc.plane_axis_1]-gc.position[gc.plane_axis_1];
clear_vector(offset);
double h_x2_div_d = -sqrt(4 * r*r - x*x - y*y)/hypot(x,y); // == -(h * 2 / d)
// If r is smaller than d, the arc is now traversing the complex plane beyond the reach of any
// real CNC, and thus - for practical reasons - we will terminate promptly:
if(isnan(h_x2_div_d)) { FAIL(STATUS_FLOATING_POINT_ERROR); return(gc.status_code); }
// Invert the sign of h_x2_div_d if the circle is counter clockwise (see sketch below)
if (gc.motion_mode == MOTION_MODE_CCW_ARC) { h_x2_div_d = -h_x2_div_d; }
/* The counter clockwise circle lies to the left of the target direction. When offset is positive,
the left hand circle will be generated - when it is negative the right hand circle is generated.
T <-- Target position
^
Clockwise circles with this center | Clockwise circles with this center will have
will have > 180 deg of angular travel | < 180 deg of angular travel, which is a good thing!
\ | /
center of arc when h_x2_div_d is positive -> x <----- | -----> x <- center of arc when h_x2_div_d is negative
|
|
C <-- Current position */
// Negative R is g-code-alese for "I want a circle with more than 180 degrees of travel" (go figure!),
// even though it is advised against ever generating such circles in a single line of g-code. By
// inverting the sign of h_x2_div_d the center of the circles is placed on the opposite side of the line of
// travel and thus we get the unadvisably long arcs as prescribed.
if (r < 0) {
h_x2_div_d = -h_x2_div_d;
r = -r; // Finished with r. Set to positive for mc_arc
}
// Complete the operation by calculating the actual center of the arc
offset[gc.plane_axis_0] = 0.5*(x-(y*h_x2_div_d));
offset[gc.plane_axis_1] = 0.5*(y+(x*h_x2_div_d));
} else { // Offset mode specific computations
r = hypot(offset[gc.plane_axis_0], offset[gc.plane_axis_1]); // Compute arc radius for mc_arc
}
// Set clockwise/counter-clockwise sign for mc_arc computations
uint8_t isclockwise = false;
if (gc.motion_mode == MOTION_MODE_CW_ARC) { isclockwise = true; }
// Trace the arc
mc_arc(gc.position, target, offset, gc.plane_axis_0, gc.plane_axis_1, gc.plane_axis_2,
(gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode,
r, isclockwise, gc.nominal_laser_intensity);
break;
}
}
// 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.
memcpy(gc.position, target, sizeof(double)*3); // gc.position[] = target[];
return(gc.status_code);
}
// Directs and executes one line of formatted input from protocol_process. While mostly
// incoming streaming g-code blocks, this also executes Grbl internal commands, such as
// settings, initiating the homing cycle, and toggling switch states. This differs from
// the runtime command module by being susceptible to when Grbl is ready to execute the
// next line during a cycle, so for switches like block delete, the switch only effects
// the lines that are processed afterward, not necessarily real-time during a cycle,
// since there are motions already stored in the buffer. However, this 'lag' should not
// be an issue, since these commands are not typically used during a cycle.
uint8_t protocol_execute_line(char *line)
{
// Grbl internal command and parameter lines are of the form '$4=374.3' or '$' for help
if(line[0] == '$') {
uint8_t char_counter = 1;
uint8_t helper_var = 0; // Helper variable
float parameter, value;
switch( line[char_counter] ) {
case 0 : report_grbl_help(); break;
case '$' : // Prints Grbl settings
if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
else { report_grbl_settings(); }
break;
case '#' : // Print gcode parameters
if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
else { report_gcode_parameters(); }
break;
case 'G' : // Prints gcode parser state
if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
else { report_gcode_modes(); }
break;
case 'C' : // Set check g-code mode
if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
// Perform reset when toggling off. Check g-code mode should only work if Grbl
// is idle and ready, regardless of alarm locks. This is mainly to keep things
// simple and consistent.
if ( sys.state == STATE_CHECK_MODE ) {
mc_reset();
report_feedback_message(MESSAGE_DISABLED);
} else {
if (sys.state) { return(STATUS_IDLE_ERROR); }
sys.state = STATE_CHECK_MODE;
report_feedback_message(MESSAGE_ENABLED);
}
break;
case 'X' : // Disable alarm lock
if ( line[++char_counter] != 0 ) { return(STATUS_UNSUPPORTED_STATEMENT); }
if (sys.state == STATE_ALARM) {
report_feedback_message(MESSAGE_ALARM_UNLOCK);
sys.state = STATE_IDLE;
// Don't run startup script. Prevents stored moves in startup from causing accidents.
}
break;
case 'H' : // Perform homing cycle
if (bit_istrue(settings.flags,BITFLAG_HOMING_ENABLE)) {
// Only perform homing if Grbl is idle or lost.
if ( sys.state==STATE_IDLE || sys.state==STATE_ALARM ) {
mc_go_home();
if (!sys.abort) { protocol_execute_startup(); } // Execute startup scripts after successful homing.
} else { return(STATUS_IDLE_ERROR); }
} else { return(STATUS_SETTING_DISABLED); }
break;
// case 'J' : break; // Jogging methods
// TODO: Here jogging can be placed for execution as a seperate subprogram. It does not need to be
// susceptible to other runtime commands except for e-stop. The jogging function is intended to
// be a basic toggle on/off with controlled acceleration and deceleration to prevent skipped
// steps. The user would supply the desired feedrate, axis to move, and direction. Toggle on would
// start motion and toggle off would initiate a deceleration to stop. One could 'feather' the
// motion by repeatedly toggling to slow the motion to the desired location. Location data would
// need to be updated real-time and supplied to the user through status queries.
// More controlled exact motions can be taken care of by inputting G0 or G1 commands, which are
// handled by the planner. It would be possible for the jog subprogram to insert blocks into the
// block buffer without having the planner plan them. It would need to manage de/ac-celerations
// on its own carefully. This approach could be effective and possibly size/memory efficient.
case 'N' : // Startup lines.
if ( line[++char_counter] == 0 ) { // Print startup lines
for (helper_var=0; helper_var < N_STARTUP_LINE; helper_var++) {
if (!(settings_read_startup_line(helper_var, line))) {
report_status_message(STATUS_SETTING_READ_FAIL);
} else {
report_startup_line(helper_var,line);
}
}
break;
} else { // Store startup line
helper_var = true; // Set helper_var to flag storing method.
// No break. Continues into default: to read remaining command characters.
}
default : // Storing setting methods
if(!read_float(line, &char_counter, ¶meter)) { return(STATUS_BAD_NUMBER_FORMAT); }
if(line[char_counter++] != '=') { return(STATUS_UNSUPPORTED_STATEMENT); }
if (helper_var) { // Store startup line
// Prepare sending gcode block to gcode parser by shifting all characters
helper_var = char_counter; // Set helper variable as counter to start of gcode block
do {
line[char_counter-helper_var] = line[char_counter];
} while (line[char_counter++] != 0);
// Execute gcode block to ensure block is valid.
helper_var = gc_execute_line(line); // Set helper_var to returned status code.
if (helper_var) { return(helper_var); }
else {
helper_var = trunc(parameter); // Set helper_var to int value of parameter
settings_store_startup_line(helper_var,line);
}
} else { // Store global setting.
if(!read_float(line, &char_counter, &value)) { return(STATUS_BAD_NUMBER_FORMAT); }
if(line[char_counter] != 0) { return(STATUS_UNSUPPORTED_STATEMENT); }
return(settings_store_global_setting(parameter, value));
}
}
return(STATUS_OK); // If '$' command makes it to here, then everything's ok.
} else {
return(gc_execute_line(line)); // Everything else is gcode
}
}
// Executes one line of 0-terminated G-Code. The line is assumed to contain only uppercase
// characters and signed floating point values (no whitespace). Comments and block delete
// characters have been removed. All units and positions are converted and exported to grbl's
// internal functions in terms of (mm, mm/min) and absolute machine coordinates, respectively.
uint8_t gc_execute_line(char *line)
{
uint8_t char_counter = 0;
char letter;
double value;
int int_value;
uint16_t modal_group_words = 0; // Bitflag variable to track and check modal group words in block
uint8_t axis_words = 0; // Bitflag to track which XYZ(ABC) parameters exist in block
double inverse_feed_rate = -1; // negative inverse_feed_rate means no inverse_feed_rate specified
uint8_t absolute_override = false; // true(1) = absolute motion for this block only {G53}
uint8_t non_modal_action = NON_MODAL_NONE; // Tracks the actions of modal group 0 (non-modal)
double target[3], offset[3];
clear_vector(target); // XYZ(ABC) axes parameters.
clear_vector(offset); // IJK Arc offsets are incremental. Value of zero indicates no change.
gc.status_code = STATUS_OK;
/* Pass 1: Commands and set all modes. Check for modal group violations.
NOTE: Modal group numbers are defined in Table 4 of NIST RS274-NGC v3, pg.20 */
uint8_t group_number = MODAL_GROUP_NONE;
while(next_statement(&letter, &value, line, &char_counter)) {
int_value = trunc(value);
switch(letter) {
case 'G':
// Set modal group values
switch(int_value) {
case 4: case 10: case 28: case 30: case 53: case 92: group_number = MODAL_GROUP_0; break;
case 0: case 1: case 2: case 3: case 80: group_number = MODAL_GROUP_1; break;
case 17: case 18: case 19: group_number = MODAL_GROUP_2; break;
case 90: case 91: group_number = MODAL_GROUP_3; break;
case 93: case 94: group_number = MODAL_GROUP_5; break;
case 20: case 21: group_number = MODAL_GROUP_6; break;
case 54: case 55: case 56: case 57: case 58: case 59: group_number = MODAL_GROUP_12; break;
}
// Set 'G' commands
switch(int_value) {
case 0: gc.motion_mode = MOTION_MODE_SEEK; break;
case 1: gc.motion_mode = MOTION_MODE_LINEAR; break;
case 2: gc.motion_mode = MOTION_MODE_CW_ARC; break;
case 3: gc.motion_mode = MOTION_MODE_CCW_ARC; break;
case 4: non_modal_action = NON_MODAL_DWELL; break;
case 10: non_modal_action = NON_MODAL_SET_COORDINATE_DATA; break;
case 17: select_plane(X_AXIS, Y_AXIS, Z_AXIS); break;
case 18: select_plane(X_AXIS, Z_AXIS, Y_AXIS); break;
case 19: select_plane(Y_AXIS, Z_AXIS, X_AXIS); break;
case 20: gc.inches_mode = true; break;
case 21: gc.inches_mode = false; break;
case 28: case 30: non_modal_action = NON_MODAL_GO_HOME; break;
case 53: absolute_override = true; break;
case 54: case 55: case 56: case 57: case 58: case 59:
int_value -= 54; // Compute coordinate system row index (0=G54,1=G55,...)
if (int_value < N_COORDINATE_SYSTEM) {
sys.coord_select = int_value;
} else {
FAIL(STATUS_UNSUPPORTED_STATEMENT);
}
break;
case 80: gc.motion_mode = MOTION_MODE_CANCEL; break;
case 90: gc.absolute_mode = true; break;
case 91: gc.absolute_mode = false; break;
case 92:
int_value = trunc(10*value); // Multiply by 10 to pick up G92.1
switch(int_value) {
case 920: non_modal_action = NON_MODAL_SET_COORDINATE_OFFSET; break;
case 921: non_modal_action = NON_MODAL_RESET_COORDINATE_OFFSET; break;
default: FAIL(STATUS_UNSUPPORTED_STATEMENT);
}
break;
case 93: gc.inverse_feed_rate_mode = true; break;
case 94: gc.inverse_feed_rate_mode = false; break;
default: FAIL(STATUS_UNSUPPORTED_STATEMENT);
}
break;
case 'M':
// Set modal group values
switch(int_value) {
case 0: case 1: case 2: case 30: group_number = MODAL_GROUP_4; break;
case 3: case 4: case 5: group_number = MODAL_GROUP_7; break;
}
// Set 'M' commands
switch(int_value) {
case 0: gc.program_flow = PROGRAM_FLOW_PAUSED; break; // Program pause
case 1: // Program pause with optional stop on
// if (sys.opt_stop) { // TODO: Add system variable for optional stop.
gc.program_flow = PROGRAM_FLOW_PAUSED; break;
// }
case 2: case 30: gc.program_flow = PROGRAM_FLOW_COMPLETED; break; // Program end and reset
case 3: gc.spindle_direction = 1; break;
case 4: gc.spindle_direction = -1; break;
case 5: gc.spindle_direction = 0; break;
default: FAIL(STATUS_UNSUPPORTED_STATEMENT);
}
break;
}
// Check for modal group multiple command violations in the current block
if (group_number) {
if ( bit_istrue(modal_group_words,bit(group_number)) ) {
FAIL(STATUS_MODAL_GROUP_VIOLATION);
} else {
bit_true(modal_group_words,bit(group_number));
}
group_number = MODAL_GROUP_NONE; // Reset for next command.
}
}
// If there were any errors parsing this line, we will return right away with the bad news
if (gc.status_code) { return(gc.status_code); }
/* Pass 2: Parameters. All units converted according to current block commands. Position
parameters are converted and flagged to indicate a change. These can have multiple connotations
for different commands. Each will be converted to their proper value upon execution. */
double p = 0, r = 0;
uint8_t l = 0;
char_counter = 0;
while(next_statement(&letter, &value, line, &char_counter)) {
switch(letter) {
case 'F':
if (value <= 0) { FAIL(STATUS_INVALID_COMMAND); } // Must be greater than zero
if (gc.inverse_feed_rate_mode) {
inverse_feed_rate = to_millimeters(value); // seconds per motion for this motion only
} else {
gc.feed_rate = to_millimeters(value); // millimeters per minute
}
break;
case 'I': case 'J': case 'K': offset[letter-'I'] = to_millimeters(value); break;
case 'L': l = trunc(value); break;
case 'P': p = value; break;
case 'R': r = to_millimeters(value); break;
case 'S':
if (value < 0) { FAIL(STATUS_INVALID_COMMAND); } // Cannot be negative
gc.spindle_speed = value;
break;
case 'T':
if (value < 0) { FAIL(STATUS_INVALID_COMMAND); } // Cannot be negative
gc.tool = trunc(value);
break;
case 'X': target[X_AXIS] = to_millimeters(value); bit_true(axis_words,bit(X_AXIS)); break;
case 'Y': target[Y_AXIS] = to_millimeters(value); bit_true(axis_words,bit(Y_AXIS)); break;
case 'Z': target[Z_AXIS] = to_millimeters(value); bit_true(axis_words,bit(Z_AXIS)); break;
}
}
// If there were any errors parsing this line, we will return right away with the bad news
if (gc.status_code) { return(gc.status_code); }
/* Execute Commands: Perform by order of execution defined in NIST RS274-NGC.v3, Table 8, pg.41.
NOTE: Independent non-motion/settings parameters are set out of this order for code efficiency
and simplicity purposes, but this should not affect proper g-code execution. */
// ([M6]: Tool change execution should be executed here.)
// [M3,M4,M5]: Update spindle state
spindle_run(gc.spindle_direction, gc.spindle_speed);
// ([M7,M8,M9]: Coolant state should be executed here.)
// [G4,G10,G28,G30,G92,G92.1]: Perform dwell, set coordinate system data, homing, or set axis offsets.
// NOTE: These commands are in the same modal group, hence are mutually exclusive. G53 is in this
// modal group and do not effect these actions.
switch (non_modal_action) {
case NON_MODAL_DWELL:
if (p < 0) { // Time cannot be negative.
FAIL(STATUS_INVALID_COMMAND);
} else {
mc_dwell(p);
}
break;
case NON_MODAL_SET_COORDINATE_DATA:
int_value = trunc(p); // Convert p value to int.
if (l != 2 || (int_value < 1 || int_value > N_COORDINATE_SYSTEM)) { // L2 only. P1=G54, P2=G55, ...
FAIL(STATUS_UNSUPPORTED_STATEMENT);
} else if (!axis_words) { // No axis words.
FAIL(STATUS_INVALID_COMMAND);
} else {
int_value--; // Adjust p to be inline with row array index.
// Update axes defined only in block. Always in machine coordinates. Can change non-active system.
uint8_t i;
for (i=0; i<=2; i++) { // Axes indices are consistent, so loop may be used.
if ( bit_istrue(axis_words,bit(i)) ) { sys.coord_system[int_value][i] = target[i]; }
}
}
axis_words = 0; // Axis words used. Lock out from motion modes by clearing flags.
break;
case NON_MODAL_GO_HOME:
// Move to intermediate position before going home. Obeys current coordinate system and offsets
// and absolute and incremental modes.
if (axis_words) {
// Apply absolute mode coordinate offsets or incremental mode offsets.
uint8_t i;
for (i=0; i<=2; i++) { // Axes indices are consistent, so loop may be used.
if ( bit_istrue(axis_words,bit(i)) ) {
if (gc.absolute_mode) {
target[i] += sys.coord_system[sys.coord_select][i] + sys.coord_offset[i];
} else {
target[i] += gc.position[i];
}
} else {
target[i] = gc.position[i];
}
}
mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], settings.default_seek_rate, false);
}
mc_go_home();
clear_vector(gc.position); // Assumes home is at [0,0,0]
axis_words = 0; // Axis words used. Lock out from motion modes by clearing flags.
break;
case NON_MODAL_SET_COORDINATE_OFFSET:
if (!axis_words) { // No axis words
FAIL(STATUS_INVALID_COMMAND);
} else {
// Update axes defined only in block. Offsets current system to defined value. Does not update when
// active coordinate system is selected, but is still active unless G92.1 disables it.
uint8_t i;
for (i=0; i<=2; i++) { // Axes indices are consistent, so loop may be used.
if (bit_istrue(axis_words,bit(i)) ) {
sys.coord_offset[i] = gc.position[i]-sys.coord_system[sys.coord_select][i]-target[i];
}
}
}
axis_words = 0; // Axis words used. Lock out from motion modes by clearing flags.
break;
case NON_MODAL_RESET_COORDINATE_OFFSET:
clear_vector(sys.coord_offset); // Disable G92 offsets by zeroing offset vector.
break;
}
// [G0,G1,G2,G3,G80]: Perform motion modes.
// NOTE: Commands G10,G28,G30,G92 lock out and prevent axis words from use in motion modes.
// Enter motion modes only if there are axis words or a motion mode command word in the block.
if ( bit_istrue(modal_group_words,bit(MODAL_GROUP_1)) || axis_words ) {
// G1,G2,G3 require F word in inverse time mode.
if ( gc.inverse_feed_rate_mode ) {
if (inverse_feed_rate < 0 && gc.motion_mode != MOTION_MODE_CANCEL) {
FAIL(STATUS_INVALID_COMMAND);
}
}
// Absolute override G53 only valid with G0 and G1 active.
if ( absolute_override && !(gc.motion_mode == MOTION_MODE_SEEK || gc.motion_mode == MOTION_MODE_LINEAR)) {
FAIL(STATUS_INVALID_COMMAND);
}
// Report any errors.
if (gc.status_code) { return(gc.status_code); }
// Convert all target position data to machine coordinates for executing motion. Apply
// absolute mode coordinate offsets or incremental mode offsets.
// NOTE: Tool offsets may be appended to these conversions when/if this feature is added.
uint8_t i;
for (i=0; i<=2; i++) { // Axes indices are consistent, so loop may be used to save flash space.
if ( bit_istrue(axis_words,bit(i)) ) {
if (!absolute_override) { // Do not update target in absolute override mode
if (gc.absolute_mode) {
target[i] += sys.coord_system[sys.coord_select][i] + sys.coord_offset[i]; // Absolute mode
} else {
target[i] += gc.position[i]; // Incremental mode
}
}
} else {
target[i] = gc.position[i]; // No axis word in block. Keep same axis position.
}
}
switch (gc.motion_mode) {
case MOTION_MODE_CANCEL:
if (axis_words) { FAIL(STATUS_INVALID_COMMAND); } // No axis words allowed while active.
break;
case MOTION_MODE_SEEK:
if (!axis_words) { FAIL(STATUS_INVALID_COMMAND);}
else { mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], settings.default_seek_rate, false); }
break;
case MOTION_MODE_LINEAR:
if (!axis_words) { FAIL(STATUS_INVALID_COMMAND);}
else { mc_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS],
(gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode); }
break;
case MOTION_MODE_CW_ARC: case MOTION_MODE_CCW_ARC:
// Check if at least one of the axes of the selected plane has been specified. If in center
// format arc mode, also check for at least one of the IJK axes of the selected plane was sent.
if ( !( bit_false(axis_words,bit(gc.plane_axis_2)) ) ||
( !r && !offset[gc.plane_axis_0] && !offset[gc.plane_axis_1] ) ) {
FAIL(STATUS_INVALID_COMMAND);
} else {
if (r != 0) { // Arc Radius Mode
/*
We need to calculate the center of the circle that has the designated radius and passes
through both the current position and the target position. This method calculates the following
set of equations where [x,y] is the vector from current to target position, d == magnitude of
that vector, h == hypotenuse of the triangle formed by the radius of the circle, the distance to
the center of the travel vector. A vector perpendicular to the travel vector [-y,x] is scaled to the
length of h [-y/d*h, x/d*h] and added to the center of the travel vector [x/2,y/2] to form the new point
[i,j] at [x/2-y/d*h, y/2+x/d*h] which will be the center of our arc.
d^2 == x^2 + y^2
h^2 == r^2 - (d/2)^2
i == x/2 - y/d*h
j == y/2 + x/d*h
O <- [i,j]
- |
r - |
- |
- | h
- |
[0,0] -> C -----------------+--------------- T <- [x,y]
| <------ d/2 ---->|
C - Current position
T - Target position
O - center of circle that pass through both C and T
d - distance from C to T
r - designated radius
h - distance from center of CT to O
Expanding the equations:
d -> sqrt(x^2 + y^2)
h -> sqrt(4 * r^2 - x^2 - y^2)/2
i -> (x - (y * sqrt(4 * r^2 - x^2 - y^2)) / sqrt(x^2 + y^2)) / 2
j -> (y + (x * sqrt(4 * r^2 - x^2 - y^2)) / sqrt(x^2 + y^2)) / 2
Which can be written:
i -> (x - (y * sqrt(4 * r^2 - x^2 - y^2))/sqrt(x^2 + y^2))/2
j -> (y + (x * sqrt(4 * r^2 - x^2 - y^2))/sqrt(x^2 + y^2))/2
Which we for size and speed reasons optimize to:
h_x2_div_d = sqrt(4 * r^2 - x^2 - y^2)/sqrt(x^2 + y^2)
i = (x - (y * h_x2_div_d))/2
j = (y + (x * h_x2_div_d))/2
*/
// Calculate the change in position along each selected axis
double x = target[gc.plane_axis_0]-gc.position[gc.plane_axis_0];
double y = target[gc.plane_axis_1]-gc.position[gc.plane_axis_1];
clear_vector(offset);
double h_x2_div_d = -sqrt(4 * r*r - x*x - y*y)/hypot(x,y); // == -(h * 2 / d)
// If r is smaller than d, the arc is now traversing the complex plane beyond the reach of any
// real CNC, and thus - for practical reasons - we will terminate promptly:
if(isnan(h_x2_div_d)) { FAIL(STATUS_FLOATING_POINT_ERROR); return(gc.status_code); }
// Invert the sign of h_x2_div_d if the circle is counter clockwise (see sketch below)
if (gc.motion_mode == MOTION_MODE_CCW_ARC) { h_x2_div_d = -h_x2_div_d; }
/* The counter clockwise circle lies to the left of the target direction. When offset is positive,
the left hand circle will be generated - when it is negative the right hand circle is generated.
T <-- Target position
^
Clockwise circles with this center | Clockwise circles with this center will have
will have > 180 deg of angular travel | < 180 deg of angular travel, which is a good thing!
\ | /
center of arc when h_x2_div_d is positive -> x <----- | -----> x <- center of arc when h_x2_div_d is negative
|
|
C <-- Current position */
// Negative R is g-code-alese for "I want a circle with more than 180 degrees of travel" (go figure!),
// even though it is advised against ever generating such circles in a single line of g-code. By
// inverting the sign of h_x2_div_d the center of the circles is placed on the opposite side of the line of
// travel and thus we get the unadvisably long arcs as prescribed.
if (r < 0) {
h_x2_div_d = -h_x2_div_d;
r = -r; // Finished with r. Set to positive for mc_arc
}
// Complete the operation by calculating the actual center of the arc
offset[gc.plane_axis_0] = 0.5*(x-(y*h_x2_div_d));
offset[gc.plane_axis_1] = 0.5*(y+(x*h_x2_div_d));
} else { // Arc Center Format Offset Mode
r = hypot(offset[gc.plane_axis_0], offset[gc.plane_axis_1]); // Compute arc radius for mc_arc
}
// Set clockwise/counter-clockwise sign for mc_arc computations
uint8_t isclockwise = false;
if (gc.motion_mode == MOTION_MODE_CW_ARC) { isclockwise = true; }
// Trace the arc
mc_arc(gc.position, target, offset, gc.plane_axis_0, gc.plane_axis_1, gc.plane_axis_2,
(gc.inverse_feed_rate_mode) ? inverse_feed_rate : gc.feed_rate, gc.inverse_feed_rate_mode,
r, isclockwise);
}
break;
}
// Report any errors.
if (gc.status_code) { return(gc.status_code); }
// 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.
memcpy(gc.position, target, sizeof(double)*3); // gc.position[] = target[];
}
// M0,M1,M2,M30: Perform non-running program flow actions. During a program pause, the buffer may
// refill and can only be resumed by the cycle start run-time command.
if (gc.program_flow) {
plan_synchronize(); // Finish all remaining buffered motions. Program paused when complete.
sys.auto_start = false; // Disable auto cycle start.
gc.program_flow = PROGRAM_FLOW_RUNNING; // Re-enable program flow after pause complete.
// If complete, reset to reload defaults (G92.2,G54,G17,G90,G94,M48,G40,M5,M9)
if (gc.program_flow == PROGRAM_FLOW_COMPLETED) { sys.abort = true; }
}
return(gc.status_code);
}
