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Add G02/03 arc conversion/pre-processor script and example streaming script

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Beta pre-processor script used to clean and streamline g-code for
streaming and converts G02/03 arcs into linear segments. Allows for full
acceleration support if the pre-processed g-code is then streamed to
grill, sans G02/03 arcs. Added a simple example streaming script for
Python users.
This commit is contained in:
Sonny J 2011-09-03 16:08:42 -06:00
parent 5c2150daa9
commit 75bd4c5ac3
2 changed files with 257 additions and 0 deletions
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224
script/grbl_preprocess.py Executable file
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#!/usr/bin/env python
"""\
G-code preprocessor for grbl
- Converts G02/03 arcs to G01 linear interpolations
- Removes comments, block delete characters, and line numbers
- Removes spaces and capitalizes commands
- Minor input error checking
- OPTIONAL: Remove unsupported grbl G and M commands
TODO:
- More robust error checking
- Improve interface to command line options
- Improve g-code parsing to NIST standards
- Fix problem with inverse feed rates
- Positioning updates may not be correct on grbl. Need to check.
Based on GRBL 0.7b source code by Simen Svale Skogsrud
Version: 20100825
"""
import re
from math import *
from copy import *
# -= SETTINGS =-
filein = 'test.gcode' # Input file name
fileout = 'grbl.gcode' # Output file name
ndigits_in = 4 # inch significant digits after '.'
ndigits_mm = 2 # mm significant digits after '.'
mm_per_arc_segment = 0.1 # mm per arc segment
inch2mm = 25.4 # inch to mm conversion scalar
verbose = False # Verbose flag to show all progress
remove_unsupported = True # Removal flag for all unsupported statements
# Initialize parser state
gc = { 'current_xyz' : [0,0,0],
'feed_rate' : 0, # F0
'motion_mode' : 'SEEK', # G00
'plane_axis' : [0,1,2], # G17
'inches_mode' : False, # G21
'inverse_feedrate_mode' : False, # G94
'absolute_mode' : True} # G90
def unit_conv(val) : # Converts value to mm
if gc['inches_mode'] : val *= inch2mm
return(val)
def fout_conv(val) : # Returns converted value as rounded string for output file.
if gc['inches_mode'] : return( str(round(val/inch2mm,ndigits_in)) )
else : return( str(round(val,ndigits_mm)) )
# Open g-code file
fin = open(filein,'r');
fout = open(fileout,'w');
# Iterate through g-code file
l_count = 0
for line in fin:
l_count += 1 # Iterate line counter
# Strip comments/spaces/tabs/new line and capitalize. Comment MSG not supported.
block = re.sub('\s|\(.*?\)','',line).upper()
block = re.sub('\\\\','',block) # Strip \ block delete character
block = re.sub('%','',block) # Strip % program start/stop character
if len(block) == 0 : # Ignore empty blocks
print "Skipping: " + line.strip()
else : # Process valid g-code clean block. Assumes no block delete characters or comments
g_cmd = re.findall(r'[^0-9\.\-]+',block) # Extract block command characters
g_num = re.findall(r'[0-9\.\-]+',block) # Extract block numbers
# G-code block error checks
# if len(g_cmd) != len(g_num) : print block; raise Exception('Invalid block. Unbalanced word and values.')
if 'N' in g_cmd :
if g_cmd[0]!='N': raise Exception('Line number must be first command in line.')
if g_cmd.count('N') > 1: raise Exception('More than one line number in block.')
g_cmd = g_cmd[1:] # Remove line number word
g_num = g_num[1:]
# Block item repeat checks? (0<=n'M'<5, G/M modal groups)
# Initialize block state
blk = { 'next_action' : 'DEFAULT',
'absolute_override' : False,
'target_xyz' : deepcopy(gc['current_xyz']),
'offset_ijk' : [0,0,0],
'radius_mode' : False,
'unsupported': [] }
# Pass 1
for cmd,num in zip(g_cmd,g_num) :
fnum = float(num)
inum = int(fnum)
if cmd is 'G' :
if inum is 0 : gc['motion_mode'] = 'SEEK'
elif inum is 1 : gc['motion_mode'] = 'LINEAR'
elif inum is 2 : gc['motion_mode'] = 'CW_ARC'
elif inum is 3 : gc['motion_mode'] = 'CCW_ARC'
elif inum is 4 : blk['next_action'] = 'DWELL'
elif inum is 17 : gc['plane_axis'] = [0,1,2] # Select XY Plane
elif inum is 18 : gc['plane_axis'] = [0,2,1] # Select XZ Plane
elif inum is 19 : gc['plane_axis'] = [1,2,0] # Select YZ Plane
elif inum is 20 : gc['inches_mode'] = True
elif inum is 21 : gc['inches_mode'] = False
elif inum in [28,30] : blk['next_action'] = 'GO_HOME'
elif inum is 53 : blk['absolute_override'] = True
elif inum is 80 : gc['motion_mode'] = 'MOTION_CANCEL'
elif inum is 90 : gc['absolute_mode'] = True
elif inum is 91 : gc['absolute_mode'] = False
elif inum is 92 : blk['next_action'] = 'SET_OFFSET'
elif inum is 93 : gc['inverse_feedrate_mode'] = True
elif inum is 94 : gc['inverse_feedrate_mode'] = False
else :
print 'Unsupported command ' + cmd + num + ' on line ' + str(l_count)
if remove_unsupported : blk['unsupported'].append(zip(g_cmd,g_num).index((cmd,num)))
elif cmd is 'M' :
if inum in [0,1] : pass # Program Pause
elif inum in [2,30,60] : pass # Program Completed
elif inum is 3 : pass # Spindle Direction 1
elif inum is 4 : pass # Spindle Direction -1
elif inum is 5 : pass # Spindle Direction 0
else :
print 'Unsupported command ' + cmd + num + ' on line ' + str(l_count)
if remove_unsupported : blk['unsupported'].append(zip(g_cmd,g_num).index((cmd,num)))
elif cmd is 'T' : pass # Tool Number
# Pass 2
for cmd,num in zip(g_cmd,g_num) :
fnum = float(num)
if cmd is 'F' : gc['feed_rate'] = unit_conv(fnum) # Feed Rate
elif cmd in ['I','J','K'] : blk['offset_ijk'][ord(cmd)-ord('I')] = unit_conv(fnum) # Arc Center Offset
elif cmd is 'P' : p = fnum # Misc value parameter
elif cmd is 'R' : r = unit_conv(fnum); blk['radius_mode'] = True # Arc Radius Mode
elif cmd is 'S' : pass # Spindle Speed
elif cmd in ['X','Y','Z'] : # Target Coordinates
if (gc['absolute_mode'] | blk['absolute_override']) :
blk['target_xyz'][ord(cmd)-ord('X')] = unit_conv(fnum)
else :
blk['target_xyz'][ord(cmd)-ord('X')] += unit_conv(fnum)
# Execute actions
if blk['next_action'] is 'GO_HOME' :
gc['current_xyz'] = deepcopy(blk['target_xyz']) # Update position
elif blk['next_action'] is 'SET_OFFSET' :
pass
elif blk['next_action'] is 'DWELL' :
if p < 0 : raise Exception('Dwell time negative.')
else : # 'DEFAULT'
if gc['motion_mode'] is 'SEEK' :
gc['current_xyz'] = deepcopy(blk['target_xyz']) # Update position
elif gc['motion_mode'] is 'LINEAR' :
gc['current_xyz'] = deepcopy(blk['target_xyz']) # Update position
elif gc['motion_mode'] in ['CW_ARC','CCW_ARC'] :
axis = gc['plane_axis']
# Convert radius mode to ijk mode
if blk['radius_mode'] :
x = blk['target_xyz'][axis[0]]-gc['current_xyz'][axis[0]]
y = blk['target_xyz'][axis[1]]-gc['current_xyz'][axis[1]]
if not (x==0 and y==0) : raise Exception('Same target and current XYZ not allowed in arc radius mode.')
h_x2_div_d = -sqrt(4 * r*r - x*x - y*y)/hypot(x,y)
if isnan(h_x2_div_d) : raise Exception('Floating point error in arc conversion')
if gc['motion_mode'] is 'CCW_ARC' : h_x2_div_d = -h_x2_div_d
if r < 0 : h_x2_div_d = -h_x2_div_d
blk['offset_ijk'][axis[0]] = (x-(y*h_x2_div_d))/2;
blk['offset_ijk'][axis[1]] = (y+(x*h_x2_div_d))/2;
# Compute arc center, radius, theta, and depth parameters
theta_start = atan2(-blk['offset_ijk'][axis[0]], -blk['offset_ijk'][axis[1]])
theta_end = atan2(blk['target_xyz'][axis[0]] - blk['offset_ijk'][axis[0]] - gc['current_xyz'][axis[0]], \
blk['target_xyz'][axis[1]] - blk['offset_ijk'][axis[1]] - gc['current_xyz'][axis[1]])
if theta_end < theta_start : theta_end += 2*pi
radius = hypot(blk['offset_ijk'][axis[0]], blk['offset_ijk'][axis[1]])
depth = blk['target_xyz'][axis[2]]-gc['current_xyz'][axis[2]]
center_x = gc['current_xyz'][axis[0]]-sin(theta_start)*radius
center_y = gc['current_xyz'][axis[1]]-cos(theta_start)*radius
# Compute arc incremental linear segment parameters
angular_travel = theta_end-theta_start
if gc['motion_mode'] is 'CCW_ARC' : angular_travel = angular_travel-2*pi
millimeters_of_travel = hypot(angular_travel*radius, fabs(depth))
if millimeters_of_travel is 0 : raise Exception('G02/03 arc travel is zero')
segments = int(round(millimeters_of_travel/mm_per_arc_segment))
if segments is 0 : raise Exception('G02/03 zero length arc segment')
# ??? # if gc['inverse_feedrate_mode'] : gc['feed_rate'] *= segments
theta_per_segment = angular_travel/segments
depth_per_segment = depth/segments
# Generate arc linear segments
if verbose: print 'Converting: '+ block + ' : ' + str(l_count)
fout.write('G01F'+fout_conv(gc['feed_rate']))
if not gc['absolute_mode'] : fout.write('G90')
arc_target = [0,0,0]
for i in range(1,segments+1) :
if i < segments :
arc_target[axis[0]] = center_x + radius * sin(theta_start + i*theta_per_segment)
arc_target[axis[1]] = center_y + radius * cos(theta_start + i*theta_per_segment)
arc_target[axis[2]] = gc['current_xyz'][axis[2]] + i*depth_per_segment
else :
arc_target = deepcopy(blk['target_xyz']) # Last segment at target_xyz
# Write only changed variables.
if arc_target[0] != gc['current_xyz'][0] : fout.write('X'+fout_conv(arc_target[0]))
if arc_target[1] != gc['current_xyz'][1] : fout.write('Y'+fout_conv(arc_target[1]))
if arc_target[2] != gc['current_xyz'][2] : fout.write('Z'+fout_conv(arc_target[2]))
fout.write('\n')
gc['current_xyz'] = deepcopy(arc_target) # Update position
if not gc['absolute_mode'] : fout.write('G91\n')
# Rebuild original gcode block sans line numbers, extra characters, and unsupported commands
if gc['motion_mode'] not in ['CW_ARC','CCW_ARC'] :
if remove_unsupported and len(blk['unsupported']) :
for i in blk['unsupported'][::-1] : del g_cmd[i]; del g_num[i]
out_block = "".join([i+j for (i,j) in zip(g_cmd,g_num)])
if len(out_block) :
if verbose : print "Writing: " + out_block + ' : ' + str(l_count)
fout.write(out_block + '\n')
print 'Done!'
# Close files
fin.close()
fout.close()

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script/simple_stream.py Executable file
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#!/usr/bin/env python
"""\
Simple g-code streaming script for grbl
"""
import serial
import time
# Open grbl serial port
s = serial.Serial('/dev/tty.usbmodem1811',9600)
# Open g-code file
f = open('grbl.gcode','r');
# Wake up grbl
s.write("\r\n\r\n")
time.sleep(2) # Wait for grbl to initialize
s.flushInput() # Flush startup text in serial input
# Stream g-code to grbl
for line in f:
l = line.strip() # Strip all EOL characters for consistency
print 'Sending: ' + l,
s.write(l + '\n') # Send g-code block to grbl
grbl_out = s.readline() # Wait for grbl response with carriage return
print ' : ' + grbl_out.strip()
# Wait here until grbl is finished to close serial port and file.
raw_input(" Press <Enter> to exit and disable grbl.")
# Close file and serial port
f.close()
s.close()