shaper_calibrate: Estimate max_accel to avoid excessive smoothing

Signed-off-by: Dmitry Butyugin <dmbutyugin@google.com>
This commit is contained in:
Dmitry Butyugin 2021-01-29 19:21:04 +01:00 committed by KevinOConnor
parent 8c369b54ab
commit 73a39370ad
2 changed files with 37 additions and 10 deletions

View File

@ -97,10 +97,8 @@ def get_3hump_ei_shaper(shaper_freq, damping_ratio):
T = [0., .5*t_d, t_d, 1.5*t_d, 2.*t_d]
return (A, T)
def get_shaper_smoothing(shaper):
# Smoothing calculation params
HALF_ACCEL = 2500.
SCV = 5.
def get_shaper_smoothing(shaper, accel=5000, scv=5.):
half_accel = accel * .5
A, T = shaper
inv_D = 1. / sum(A)
@ -113,8 +111,8 @@ def get_shaper_smoothing(shaper):
for i in range(n):
if T[i] >= ts:
# Calculate offset for one of the axes
offset_90 += A[i] * (SCV + HALF_ACCEL * (T[i]-ts)) * (T[i]-ts)
offset_180 += A[i] * HALF_ACCEL * (T[i]-ts)**2
offset_90 += A[i] * (scv + half_accel * (T[i]-ts)) * (T[i]-ts)
offset_180 += A[i] * half_accel * (T[i]-ts)**2
offset_90 *= inv_D * math.sqrt(2.)
offset_180 *= inv_D
return max(offset_90, offset_180)
@ -164,7 +162,7 @@ class CalibrationData:
CalibrationResult = collections.namedtuple(
'CalibrationResult',
('name', 'freq', 'vals', 'vibrs', 'smoothing', 'score'))
('name', 'freq', 'vals', 'vibrs', 'smoothing', 'score', 'max_accel'))
class ShaperCalibrate:
def __init__(self, printer):
@ -333,6 +331,7 @@ class ShaperCalibrate:
shaper_vals = np.maximum(shaper_vals, vals)
if vibrations > shaper_vibrations:
shaper_vibrations = vibrations
max_accel = self.find_shaper_max_accel(shaper)
# The score trying to minimize vibrations, but also accounting
# the growth of smoothing. The formula itself does not have any
# special meaning, it simply shows good results on real user data
@ -341,7 +340,7 @@ class ShaperCalibrate:
CalibrationResult(
name=shaper_cfg.name, freq=test_freq, vals=shaper_vals,
vibrs=shaper_vibrations, smoothing=shaper_smoothing,
score=shaper_score))
score=shaper_score, max_accel=max_accel))
if best_res is None or best_res.vibrs > results[-1].vibrs:
# The current frequency is better for the shaper.
best_res = results[-1]
@ -353,6 +352,30 @@ class ShaperCalibrate:
selected = res
return selected
def _bisect(self, func):
left = right = 1.
while not func(left):
right = left
left *= .5
if right == left:
while func(right):
right *= 2.
while right - left > 1e-8:
middle = (left + right) * .5
if func(middle):
left = middle
else:
right = middle
return left
def find_shaper_max_accel(self, shaper):
# Just some empirically chosen value which produces good projections
# for max_accel without much smoothing
TARGET_SMOOTHING = 0.12
max_accel = self._bisect(lambda test_accel: get_shaper_smoothing(
shaper, test_accel) <= TARGET_SMOOTHING)
return max_accel
def find_best_shaper(self, calibration_data, max_smoothing, logger=None):
best_shaper = None
all_shapers = []
@ -364,6 +387,9 @@ class ShaperCalibrate:
"(vibrations = %.1f%%, smoothing ~= %.3f)" % (
shaper.name, shaper.freq, shaper.vibrs * 100.,
shaper.smoothing))
logger("To avoid too much smoothing with '%s', suggested "
"max_accel <= %.0f mm/sec^2" % (
shaper.name, round(shaper.max_accel / 100.) * 100.))
all_shapers.append(shaper)
if (best_shaper is None or shaper.score * 1.2 < best_shaper.score or
(shaper.score * 1.1 < best_shaper.score and

View File

@ -100,9 +100,10 @@ def plot_freq_response(lognames, calibration_data, shapers,
ax2.set_ylabel('Shaper vibration reduction (ratio)')
best_shaper_vals = None
for shaper in shapers:
label = "%s (%.1f Hz, vibr=%.1f%%, sm~=%.2f)" % (
label = "%s (%.1f Hz, vibr=%.1f%%, sm~=%.2f, accel<=%.f)" % (
shaper.name.upper(), shaper.freq,
shaper.vibrs * 100., shaper.smoothing)
shaper.vibrs * 100., shaper.smoothing,
round(shaper.max_accel / 100.) * 100.)
linestyle = 'dotted'
if shaper.name == selected_shaper:
linestyle = 'dashdot'