angle: Initial support for angle sensor calibration

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2021-08-21 22:05:53 -04:00
parent 74937326d3
commit aec742ece4
4 changed files with 286 additions and 3 deletions

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@ -354,7 +354,8 @@ A request may look like:
and might return:
`{"id": 123,"result":{"header":["time","angle"]}}`
and might later produce asynchronous messages such as:
`{"params":{"errors":0,"data":[[1290.951905,-5063],[1290.952321,-5065]]}}`
`{"params":{"position_offset":3.151562,"errors":0,
"data":[[1290.951905,-5063],[1290.952321,-5065]]}}`
The "header" field in the initial query response is used to describe
the fields found in later "data" responses.

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@ -4007,6 +4007,7 @@ Magnetic hall angle sensor support for reading stepper motor angle
shaft measurements using a1333, as5047d, or tle5012b SPI chips. The
measurements are available via the [API Server](API_Server.md) and
[motion analysis tool](Debugging.md#motion-analysis-and-data-logging).
See the [G-Code reference](G-Codes.md#angle) for available commands.
```
[angle my_angle_sensor]
@ -4017,6 +4018,12 @@ sensor_type:
#sample_period: 0.000400
# The query period (in seconds) to use during measurements. The
# default is 0.000400 (which is 2500 samples per second).
#stepper:
# The name of the stepper that the angle sensor is attached to (eg,
# "stepper_x"). Setting this value enables an angle calibration
# tool. To use this feature, the Python "numpy" package must be
# installed. The default is to not enable angle calibration for the
# angle sensor.
cs_pin:
# The SPI enable pin for the sensor. This parameter must be provided.
#spi_speed:

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@ -106,6 +106,27 @@ VAL=<value>`: Writes raw "value" into a register "register". Both
"value" and "register" can be a decimal or a hexadecimal integer. Use
with care, and refer to ADXL345 data sheet for the reference.
### [angle]
The following commands are available when an
[angle config section](Config_Reference.md#angle) is enabled.
#### ANGLE_CALIBRATE
`ANGLE_CALIBRATE CHIP=<chip_name>`: Perform angle calibration on the
given sensor (there must be an `[angle chip_name]` config section that
has specified a `stepper` parameter). IMPORTANT - this tool will
command the stepper motor to move without checking the normal
kinematic boundary limits. Ideally the motor should be disconnected
from any printer carriage before performing calibration. If the
stepper can not be disconnected from the printer, make sure the
carriage is near the center of its rail before starting calibration.
(The stepper motor may move forwards or backwards two full rotations
during this test.) After completing this test use the `SAVE_CONFIG`
command to save the calibration data to the config file. In order to
use this tool the Python "numpy" package must be installed (see the
[measuring resonance document](Measuring_Resonances.md#software-installation)
for more information).
### [bed_mesh]
The following commands are available when the

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@ -3,12 +3,261 @@
# Copyright (C) 2021,2022 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import logging, threading
import logging, math, threading
from . import bus, motion_report
MIN_MSG_TIME = 0.100
TCODE_ERROR = 0xff
TRINAMIC_DRIVERS = ["tmc2130", "tmc2208", "tmc2209", "tmc2660", "tmc5160"]
CALIBRATION_BITS = 6 # 64 entries
ANGLE_BITS = 16 # angles range from 0..65535
class AngleCalibration:
def __init__(self, config):
self.printer = config.get_printer()
self.name = config.get_name()
self.stepper_name = config.get('stepper', None)
if self.stepper_name is None:
# No calibration
return
try:
import numpy
except:
raise config.error("Angle calibration requires numpy module")
sconfig = config.getsection(self.stepper_name)
sconfig.getint('microsteps', note_valid=False)
self.tmc_module = self.mcu_stepper = None
# Current calibration data
self.mcu_pos_offset = None
self.angle_phase_offset = 0.
self.calibration_reversed = False
self.calibration = []
cal = config.get('calibrate', None)
if cal is not None:
data = [d.strip() for d in cal.split(',')]
angles = [float(d) for d in data if d]
self.load_calibration(angles)
# Register commands
self.printer.register_event_handler("stepper:sync_mcu_position",
self.handle_sync_mcu_pos)
self.printer.register_event_handler("klippy:connect", self.connect)
cname = self.name.split()[-1]
gcode = self.printer.lookup_object('gcode')
gcode.register_mux_command("ANGLE_CALIBRATE", "CHIP",
cname, self.cmd_ANGLE_CALIBRATE,
desc=self.cmd_ANGLE_CALIBRATE_help)
def handle_sync_mcu_pos(self, mcu_stepper):
if mcu_stepper.get_name() == self.stepper_name:
self.mcu_pos_offset = None
def calc_mcu_pos_offset(self, sample):
# Lookup phase information
mcu_phase_offset, phases = self.tmc_module.get_phase_offset()
if mcu_phase_offset is None:
return
# Find mcu position at time of sample
angle_time, angle_pos = sample
mcu_pos = self.mcu_stepper.get_past_mcu_position(angle_time)
# Convert angle_pos to mcu_pos units
microsteps, full_steps = self.get_microsteps()
angle_to_mcu_pos = full_steps * microsteps / float(1<<ANGLE_BITS)
angle_mpos = angle_pos * angle_to_mcu_pos
# Calculate adjustment for stepper phases
phase_diff = ((angle_mpos + self.angle_phase_offset * angle_to_mcu_pos)
- (mcu_pos + mcu_phase_offset)) % phases
if phase_diff > phases//2:
phase_diff -= phases
# Store final offset
self.mcu_pos_offset = mcu_pos - (angle_mpos - phase_diff)
def apply_calibration(self, samples):
calibration = self.calibration
if not calibration:
return None
calibration_reversed = self.calibration_reversed
interp_bits = ANGLE_BITS - CALIBRATION_BITS
interp_mask = (1 << interp_bits) - 1
interp_round = 1 << (interp_bits - 1)
for i, (samp_time, angle) in enumerate(samples):
bucket = (angle & 0xffff) >> interp_bits
cal1 = calibration[bucket]
cal2 = calibration[bucket + 1]
adj = (angle & interp_mask) * (cal2 - cal1)
adj = cal1 + ((adj + interp_round) >> interp_bits)
angle_diff = (angle - adj) & 0xffff
angle_diff -= (angle_diff & 0x8000) << 1
new_angle = angle - angle_diff
if calibration_reversed:
new_angle = -new_angle
samples[i] = (samp_time, new_angle)
if self.mcu_pos_offset is None:
self.calc_mcu_pos_offset(samples[0])
if self.mcu_pos_offset is None:
return None
return self.mcu_stepper.mcu_to_commanded_position(self.mcu_pos_offset)
def load_calibration(self, angles):
# Calculate linear intepolation calibration buckets by solving
# linear equations
angle_max = 1 << ANGLE_BITS
calibration_count = 1 << CALIBRATION_BITS
bucket_size = angle_max // calibration_count
full_steps = len(angles)
nominal_step = float(angle_max) / full_steps
self.angle_phase_offset = (angles.index(min(angles)) & 3) * nominal_step
self.calibration_reversed = angles[-2] > angles[-1]
if self.calibration_reversed:
angles = list(reversed(angles))
first_step = angles.index(min(angles))
angles = angles[first_step:] + angles[:first_step]
import numpy
eqs = numpy.zeros((full_steps, calibration_count))
ans = numpy.zeros((full_steps,))
for step, angle in enumerate(angles):
int_angle = int(angle + .5) % angle_max
bucket = int(int_angle / bucket_size)
bucket_start = bucket * bucket_size
ang_diff = angle - bucket_start
ang_diff_per = ang_diff / bucket_size
eq = eqs[step]
eq[bucket] = 1. - ang_diff_per
eq[(bucket + 1) % calibration_count] = ang_diff_per
ans[step] = float(step * nominal_step)
if bucket + 1 >= calibration_count:
ans[step] -= ang_diff_per * angle_max
sol = numpy.linalg.lstsq(eqs, ans, rcond=None)[0]
isol = [int(s + .5) for s in sol]
self.calibration = isol + [isol[0] + angle_max]
def lookup_tmc(self):
for driver in TRINAMIC_DRIVERS:
driver_name = "%s %s" % (driver, self.stepper_name)
module = self.printer.lookup_object(driver_name, None)
if module is not None:
return module
raise self.printer.command_error("Unable to find TMC driver for %s"
% (self.stepper_name,))
def connect(self):
self.tmc_module = self.lookup_tmc()
fmove = self.printer.lookup_object('force_move')
self.mcu_stepper = fmove.lookup_stepper(self.stepper_name)
def get_microsteps(self):
configfile = self.printer.lookup_object('configfile')
sconfig = configfile.get_status(None)['settings']
stconfig = sconfig.get(self.stepper_name, {})
microsteps = stconfig['microsteps']
full_steps = stconfig['full_steps_per_rotation']
return microsteps, full_steps
def get_stepper_phase(self):
mcu_phase_offset, phases = self.tmc_module.get_phase_offset()
if mcu_phase_offset is None:
raise self.printer.command_error("Driver phase not known for %s"
% (self.stepper_name,))
mcu_pos = self.mcu_stepper.get_mcu_position()
return (mcu_pos + mcu_phase_offset) % phases
def do_calibration_moves(self):
move = self.printer.lookup_object('force_move').manual_move
# Start data collection
angle_sensor = self.printer.lookup_object(self.name)
cconn = angle_sensor.start_internal_client()
# Move stepper several turns (to allow internal sensor calibration)
microsteps, full_steps = self.get_microsteps()
mcu_stepper = self.mcu_stepper
step_dist = mcu_stepper.get_step_dist()
full_step_dist = step_dist * microsteps
rotation_dist = full_steps * full_step_dist
align_dist = step_dist * self.get_stepper_phase()
move_time = 0.010
move_speed = full_step_dist / move_time
move(mcu_stepper, -(rotation_dist+align_dist), move_speed)
move(mcu_stepper, 2. * rotation_dist, move_speed)
move(mcu_stepper, -2. * rotation_dist, move_speed)
move(mcu_stepper, .5 * rotation_dist - full_step_dist, move_speed)
# Move to each full step position
toolhead = self.printer.lookup_object('toolhead')
times = []
samp_dist = full_step_dist
for i in range(2 * full_steps):
move(mcu_stepper, samp_dist, move_speed)
start_query_time = toolhead.get_last_move_time() + 0.050
end_query_time = start_query_time + 0.050
times.append((start_query_time, end_query_time))
toolhead.dwell(0.150)
if i == full_steps-1:
# Reverse direction and test each full step again
move(mcu_stepper, .5 * rotation_dist, move_speed)
move(mcu_stepper, -.5 * rotation_dist + samp_dist, move_speed)
samp_dist = -samp_dist
move(mcu_stepper, .5*rotation_dist + align_dist, move_speed)
toolhead.wait_moves()
# Finish data collection
cconn.finalize()
msgs = cconn.get_messages()
# Correlate query responses
cal = {}
step = 0
for msg in msgs:
for query_time, pos in msg['params']['data']:
# Add to step tracking
while step < len(times) and query_time > times[step][1]:
step += 1
if step < len(times) and query_time >= times[step][0]:
cal.setdefault(step, []).append(pos)
if len(cal) != len(times):
raise self.printer.command_error(
"Failed calibration - incomplete sensor data")
fcal = { i: cal[i] for i in range(full_steps) }
rcal = { full_steps-i-1: cal[i+full_steps] for i in range(full_steps) }
return fcal, rcal
def calc_angles(self, meas):
total_count = total_variance = 0
angles = {}
for step, data in meas.items():
count = len(data)
angle_avg = float(sum(data)) / count
angles[step] = angle_avg
total_count += count
total_variance += sum([(d - angle_avg)**2 for d in data])
return angles, math.sqrt(total_variance / total_count), total_count
cmd_ANGLE_CALIBRATE_help = "Calibrate angle sensor to stepper motor"
def cmd_ANGLE_CALIBRATE(self, gcmd):
# Perform calibration movement and capture
old_calibration = self.calibration
self.calibration = []
try:
fcal, rcal = self.do_calibration_moves()
finally:
self.calibration = old_calibration
# Calculate each step position average and variance
microsteps, full_steps = self.get_microsteps()
fangles, fstd, ftotal = self.calc_angles(fcal)
rangles, rstd, rtotal = self.calc_angles(rcal)
if (len({a: i for i, a in fangles.items()}) != len(fangles)
or len({a: i for i, a in rangles.items()}) != len(rangles)):
raise self.printer.command_error(
"Failed calibration - sensor not updating for each step")
merged = { i: fcal[i] + rcal[i] for i in range(full_steps) }
angles, std, total = self.calc_angles(merged)
gcmd.respond_info("angle: stddev=%.3f (%.3f forward / %.3f reverse)"
" in %d queries" % (std, fstd, rstd, total))
# Order data with lowest/highest magnet position first
anglist = [angles[i] % 0xffff for i in range(full_steps)]
if angles[0] > angles[1]:
first_ang = max(anglist)
else:
first_ang = min(anglist)
first_phase = anglist.index(first_ang) & ~3
anglist = anglist[first_phase:] + anglist[:first_phase]
# Save results
cal_contents = []
for i, angle in enumerate(anglist):
if not i % 8:
cal_contents.append('\n')
cal_contents.append("%.1f" % (angle,))
cal_contents.append(',')
cal_contents.pop()
configfile = self.printer.lookup_object('configfile')
configfile.remove_section(self.name)
configfile.set(self.name, 'calibrate', ''.join(cal_contents))
class HelperA1333:
SPI_MODE = 3
SPI_SPEED = 10000000
@ -51,6 +300,7 @@ class Angle:
self.printer = config.get_printer()
self.sample_period = config.getfloat('sample_period', SAMPLE_PERIOD,
above=0.)
self.calibration = AngleCalibration(config)
# Measurement conversion
self.start_clock = self.time_shift = self.sample_ticks = 0
self.last_sequence = self.last_angle = 0
@ -148,7 +398,9 @@ class Angle:
samples, error_count = self._extract_samples(raw_samples)
if not samples:
return {}
return {'data': samples, 'errors': error_count}
offset = self.calibration.apply_calibration(samples)
return {'data': samples, 'errors': error_count,
'position_offset': offset}
def _start_measurements(self):
if self.is_measuring():
return
@ -183,6 +435,8 @@ class Angle:
self.api_dump.add_client(web_request)
hdr = ('time', 'angle')
web_request.send({'header': hdr})
def start_internal_client(self):
return self.api_dump.add_internal_client()
def load_config_prefix(config):
return Angle(config)