149 lines
4.8 KiB
Python
Executable File
149 lines
4.8 KiB
Python
Executable File
#!/usr/bin/env python2
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# Generate extruder pressure advance motion graphs
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#
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# Copyright (C) 2019 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import math, optparse, datetime
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import matplotlib
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SEG_TIME = .000100
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INV_SEG_TIME = 1. / SEG_TIME
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######################################################################
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# Basic trapezoid motion
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######################################################################
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# List of moves: [(start_v, end_v, move_t), ...]
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Moves = [
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(0., 0., .200),
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(0., 100., None), (100., 100., .200), (100., 60., None),
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(60., 100., None), (100., 100., .200), (100., 0., None),
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(0., 0., .300)
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]
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EXTRUDE_R = (.4 * .4 * .75) / (math.pi * (1.75 / 2.)**2)
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ACCEL = 3000. * EXTRUDE_R
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def gen_positions():
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out = []
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start_d = start_t = t = 0.
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for start_v, end_v, move_t in Moves:
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start_v *= EXTRUDE_R
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end_v *= EXTRUDE_R
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if move_t is None:
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move_t = abs(end_v - start_v) / ACCEL
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half_accel = 0.
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if end_v > start_v:
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half_accel = .5 * ACCEL
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elif start_v > end_v:
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half_accel = -.5 * ACCEL
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end_t = start_t + move_t
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while t <= end_t:
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rel_t = t - start_t
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out.append(start_d + (start_v + half_accel * rel_t) * rel_t)
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t += SEG_TIME
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start_d += (start_v + half_accel * move_t) * move_t
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start_t = end_t
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return out
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def gen_deriv(data):
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return [0.] + [(data[i+1] - data[i]) * INV_SEG_TIME
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for i in range(len(data)-1)]
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def time_to_index(t):
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return int(t * INV_SEG_TIME + .5)
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######################################################################
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# Pressure advance
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######################################################################
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PA_HALF_SMOOTH_T = .040 / 2.
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PRESSURE_ADVANCE = .045
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def calc_pa_raw(t, positions):
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pa = PRESSURE_ADVANCE * INV_SEG_TIME
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i = time_to_index(t)
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return positions[i] + pa * (positions[i+1] - positions[i])
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def calc_pa_weighted(t, positions):
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base_index = time_to_index(t)
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start_index = time_to_index(t - PA_HALF_SMOOTH_T) + 1
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end_index = time_to_index(t + PA_HALF_SMOOTH_T)
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diff = .5 * (end_index - start_index)
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pa = PRESSURE_ADVANCE * INV_SEG_TIME
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pa_data = [(positions[i] + pa * (positions[i+1] - positions[i]))
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* (diff - abs(i-base_index))
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for i in range(start_index, end_index)]
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return sum(pa_data) / diff**2
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######################################################################
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# Plotting and startup
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######################################################################
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MARGIN_TIME = 0.100
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def plot_motion():
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# Nominal motion
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positions = gen_positions()
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drop = int(MARGIN_TIME * INV_SEG_TIME)
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times = [SEG_TIME * t for t in range(len(positions))][drop:-drop]
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velocities = gen_deriv(positions[drop:-drop])
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# Motion with pressure advance
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pa_positions = [calc_pa_raw(t, positions) for t in times]
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pa_velocities = gen_deriv(pa_positions)
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# Smoothed motion
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sm_positions = [calc_pa_weighted(t, positions) for t in times]
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sm_velocities = gen_deriv(sm_positions)
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# Build plot
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shift_times = [t - MARGIN_TIME for t in times]
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fig, ax1 = matplotlib.pyplot.subplots(nrows=1, sharex=True)
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ax1.set_title("Extruder Velocity")
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ax1.set_ylabel('Velocity (mm/s)')
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pa_plot, = ax1.plot(shift_times, pa_velocities, 'r',
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label='Pressure Advance', alpha=0.3)
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nom_plot, = ax1.plot(shift_times, velocities, 'black', label='Nominal')
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sm_plot, = ax1.plot(shift_times, sm_velocities, 'g', label='Smooth PA',
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alpha=0.9)
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fontP = matplotlib.font_manager.FontProperties()
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fontP.set_size('x-small')
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ax1.legend(handles=[nom_plot, pa_plot, sm_plot], loc='best', prop=fontP)
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ax1.set_xlabel('Time (s)')
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ax1.grid(True)
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fig.tight_layout()
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return fig
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def setup_matplotlib(output_to_file):
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global matplotlib
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if output_to_file:
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matplotlib.rcParams.update({'figure.autolayout': True})
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matplotlib.use('Agg')
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import matplotlib.pyplot, matplotlib.dates, matplotlib.font_manager
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import matplotlib.ticker
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def main():
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# Parse command-line arguments
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usage = "%prog [options]"
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opts = optparse.OptionParser(usage)
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opts.add_option("-o", "--output", type="string", dest="output",
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default=None, help="filename of output graph")
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options, args = opts.parse_args()
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if len(args) != 0:
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opts.error("Incorrect number of arguments")
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# Draw graph
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setup_matplotlib(options.output is not None)
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fig = plot_motion()
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# Show graph
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if options.output is None:
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matplotlib.pyplot.show()
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else:
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fig.set_size_inches(6, 2.5)
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fig.savefig(options.output)
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if __name__ == '__main__':
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main()
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