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stepper: Calculate step_distance from rotation_distance 

Add support for automatically calculating the internal step_distance
from new config parameters - rotation_distance, microsteps,
full_steps_per_rotation, and gear_ratio.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2020-01-05 20:19:43 -05:00
parent 4a41d228eb
commit 7dcc778b6c
11 changed files with 128 additions and 60 deletions
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3
config/example-polar.cfg
View File

@ -10,7 +10,8 @@
step_pin: ar54
dir_pin: ar55
enable_pin: !ar38
step_distance: 0.001963495
microsteps: 16
gear_ratio: 80:16
[stepper_arm]
step_pin: ar60

9
config/example-rotary-delta.cfg
View File

@ -10,7 +10,8 @@
step_pin: ar54
dir_pin: ar55
enable_pin: !ar38
step_distance: 0.001963495
microsteps: 16
gear_ratio: 107.000:16, 60:16
endstop_pin: ^ar2
homing_speed: 50
position_endstop: 252
@ -21,14 +22,16 @@ lower_arm_length: 320.000
step_pin: ar60
dir_pin: ar61
enable_pin: !ar56
step_distance: 0.001963495
microsteps: 16
gear_ratio: 107.000:16, 60:16
endstop_pin: ^ar15
[stepper_c]
step_pin: ar46
dir_pin: ar48
enable_pin: !ar62
step_distance: 0.001963495
microsteps: 16
gear_ratio: 107.000:16, 60:16
endstop_pin: ^ar19
[extruder]

6
docs/Config_Changes.md
View File

@ -6,6 +6,12 @@ All dates in this document are approximate.
# Changes
20201218: Rotary delta and polar printers must now specify a
`gear_ratio` for their rotary steppers, and they may no longer specify
a `step_distance` parameter. See the
[config reference](Config_Reference.md#stepper) for the format of the
new gear_ratio paramter.
20201213: It is not valid to specify a Z "position_endstop" when using
"probe:z_virtual_endstop". An error will now be raised if a Z
"position_endstop" is specified with "probe:z_virtual_endstop".

81
docs/Config_Reference.md
View File

@ -127,9 +127,24 @@ enable_pin:
# Enable pin (default is enable high; use ! to indicate enable
# low). If this parameter is not provided then the stepper motor
# driver must always be enabled.
step_distance:
# Distance in mm that each step causes the axis to travel. This
rotation_distance:
# Distance (in mm) that the axis travels with one full rotation of
# the stepper motor. This parameter must be provided.
microsteps:
# The number of microsteps the stepper motor driver uses. This
# parameter must be provided.
#full_steps_per_rotation: 200
# The number of full steps for one rotation of the stepper motor.
# Set this to 200 for a 1.8 degree stepper motor or set to 400 for a
# 0.9 degree motor. The default is 200.
#gear_ratio:
# The gear ratio if the stepper motor is connected to the axis via a
# gearbox. For example, one may specify "5:1" if a 5 to 1 gearbox is
# in use. If the axis has multiple gearboxes one may specify a comma
# separated list of gear ratios (for example, "57:11, 2:1"). If a
# gear_ratio is specified then rotation_distance specifies the
# distance the axis travels for one full rotation of the final gear.
# The default is to not use a gear ratio.
endstop_pin:
# Endstop switch detection pin. This parameter must be provided for
# the X, Y, and Z steppers on cartesian style printers.
@ -367,11 +382,11 @@ kinematics: polar
# The stepper_bed section is used to describe the stepper controlling
# the bed.
[stepper_bed]
step_distance:
# On a polar printer the step_distance is the amount each step pulse
# moves the bed in radians (for example, a 1.8 degree stepper with
# 16 micro-steps would be 2 * pi * (1.8 / 360) / 16 == 0.001963495).
# This parameter must be provided.
gear_ratio:
# A gear_ratio must be specified and rotation_distance may not be
# specified. For example, if the bed has an 80 toothed pulley driven
# by a stepper with a 16 toothed pulley then one would specify a
# gear ratio of "80:16". This parameter must be provided.
max_z_velocity:
# This sets the maximum velocity (in mm/s) of movement along the z
# axis. This setting can be used to restrict the maximum speed of
@ -429,11 +444,13 @@ shoulder_height:
# right arm (at 30 degrees). This section also controls the homing
# parameters (homing_speed, homing_retract_dist) for all arms.
[stepper_a]
step_distance:
# On a rotary delta printer the step_distance is the amount each
# step pulse moves the upper arm in radians (for example, a directly
# connected 1.8 degree stepper with 16 micro-steps would be 2 * pi *
# (1.8 / 360) / 16 == 0.001963495). This parameter must be provided.
gear_ratio:
# A gear_ratio must be specified and rotation_distance may not be
# specified. For example, if the arm has an 80 toothed pulley driven
# by a pulley with 16 teeth, which is in turn connected to a 60
# toothed pulley driven by a stepper with a 16 toothed pulley, then
# one would specify a gear ratio of "80:16, 60:16". This parameter
# must be provided.
position_endstop:
# Distance (in mm) between the nozzle and the bed when the nozzle is
# in the center of the build area and the endstop triggers. This
@ -501,10 +518,10 @@ kinematics: winch
# cable winch. A minimum of 3 and a maximum of 26 cable winches may be
# defined (stepper_a to stepper_z) though it is common to define 4.
[stepper_a]
step_distance:
# The step_distance is the nominal distance (in mm) the toolhead
# moves towards the cable winch on each step pulse. This parameter
# must be provided.
rotation_distance:
# The rotation_distance is the nominal distance (in mm) the toolhead
# moves towards the cable winch for each full rotation of the
# stepper motor. This parameter must be provided.
anchor_x:
anchor_y:
anchor_z:
@ -541,7 +558,8 @@ tuning pressure advance.
step_pin:
dir_pin:
enable_pin:
step_distance:
microsteps:
rotation_distance:
# See the "stepper" section for a description of the above parameters.
nozzle_diameter:
# Diameter of the nozzle orifice (in mm). This parameter must be
@ -1613,7 +1631,8 @@ at 1 (for example, "stepper_z1", "stepper_z2", etc.).
#step_pin:
#dir_pin:
#enable_pin:
#step_distance:
#microsteps:
#rotation_distance:
# See the "stepper" section for the definition of the above parameters.
#endstop_pin:
# If an endstop_pin is defined for the additional stepper then the
@ -1670,7 +1689,8 @@ axis:
#step_pin:
#dir_pin:
#enable_pin:
#step_distance:
#microsteps:
#rotation_distance:
#endstop_pin:
#position_endstop:
#position_min:
@ -1695,7 +1715,8 @@ more information.
#step_pin:
#dir_pin:
#enable_pin:
#step_distance:
#microsteps:
#rotation_distance:
# See the "stepper" section for the definition of the above
# parameters.
```
@ -1715,7 +1736,8 @@ normal printer kinematics.
#step_pin:
#dir_pin:
#enable_pin:
#step_distance:
#microsteps:
#rotation_distance:
# See the "stepper" section for a description of these parameters.
#velocity:
# Set the default velocity (in mm/s) for the stepper. This value
@ -2531,10 +2553,6 @@ cs_pin:
#spi_software_miso_pin:
# See the "common SPI settings" section for a description of the
# above parameters.
microsteps:
# The number of microsteps to configure the driver to use. Valid
# values are 1, 2, 4, 8, 16, 32, 64, 128, 256. This parameter must
# be provided.
#interpolate: True
# If true, enable step interpolation (the driver will internally
# step at a rate of 256 micro-steps). The default is True.
@ -2601,10 +2619,6 @@ uart_pin:
# A comma separated list of pins to set prior to accessing the
# tmc2208 UART. This may be useful for configuring an analog mux for
# UART communication. The default is to not configure any pins.
microsteps:
# The number of microsteps to configure the driver to use. Valid
# values are 1, 2, 4, 8, 16, 32, 64, 128, 256. This parameter must
# be provided.
#interpolate: True
# If true, enable step interpolation (the driver will internally
# step at a rate of 256 micro-steps). The default is True.
@ -2654,7 +2668,6 @@ by the name of the corresponding stepper config section (for example,
uart_pin:
#tx_pin:
#select_pins:
#microsteps:
#interpolate: True
run_current:
#hold_current:
@ -2715,10 +2728,6 @@ cs_pin:
#spi_software_miso_pin:
# See the "common SPI settings" section for a description of the
# above parameters.
microsteps:
# The number of microsteps to configure the driver to use. Valid
# values are 1, 2, 4, 8, 16, 32, 64, 128, 256. This parameter must
# be provided.
#interpolate: True
# If true, enable step interpolation (the driver will internally
# step at a rate of 256 micro-steps). This only works if microsteps
@ -2786,10 +2795,6 @@ cs_pin:
#spi_software_miso_pin:
# See the "common SPI settings" section for a description of the
# above parameters.
microsteps:
# The number of microsteps to configure the driver to use. Valid
# values are 1, 2, 4, 8, 16, 32, 64, 128, 256. This parameter must
# be provided.
#interpolate: True
# If true, enable step interpolation (the driver will internally
# step at a rate of 256 micro-steps). The default is True.

2
docs/Config_checks.md
View File

@ -100,7 +100,7 @@ then it generally indicates that the "dir_pin" for the axis needs to
be inverted. This is done by adding a '!' to the "dir_pin" in the
printer config file (or removing it if one is already there). If the
motor moves significantly more or significantly less than one
millimeter then verify the "step_distance" setting.
millimeter then verify the "rotation_distance" setting.
Run the above test for each stepper motor defined in the config
file. (Set the STEPPER parameter of the STEPPER_BUZZ command to the

6
docs/FAQ.md
View File

@ -262,9 +262,9 @@ around 10000 steps per second. If it is requested to move at a speed
that would require a higher step rate then Marlin will generally just
step as fast as it can. Klipper is able to achieve much higher step
rates, but the stepper motor may not have sufficient torque to move at
a higher speed. So, for a Z axis with a very precise step_distance the
actual obtainable max_z_velocity may be smaller than what is
configured in Marlin.
a higher speed. So, for a Z axis with a high gearing ratio or high
microsteps setting the actual obtainable max_z_velocity may be smaller
than what is configured in Marlin.
### My TMC motor driver turns off in the middle of a print

6
docs/G-Codes.md
View File

@ -172,8 +172,10 @@ The following standard commands are supported:
[SMOOTH_TIME=<pressure_advance_smooth_time>]`: Set pressure advance
parameters. If EXTRUDER is not specified, it defaults to the active
extruder.
- `SET_EXTRUDER_STEP_DISTANCE [EXTRUDER=<config_name>] [DISTANCE=<distance>]`:
Set a new value for the provided extruder's step_distance. Value is
- `SET_EXTRUDER_STEP_DISTANCE [EXTRUDER=<config_name>]
[DISTANCE=<distance>]`: Set a new value for the provided extruder's
"step distance". The "step distance" is
`rotation_distance/(full_steps_per_rotation*microsteps)`. Value is
not retained on Klipper reset. Use with caution, small changes can
result in excessive pressure between extruder and hot end. Do proper
calibration steps with filament before use. If 'DISTANCE' value is

11
docs/Probe_Calibrate.md
View File

@ -114,11 +114,12 @@ Recv: // probe accuracy results: maximum 2.519448, minimum 2.506948, range 0.012
Ideally the tool will report an identical maximum and minimum value.
(That is, ideally the probe obtains an identical result on all ten
probes.) However, it's normal for the minimum and maximum values to
differ by one Z step_distance or up to 5 microns (.005mm). The
distance between the minimum and the maximum value is called the
range. So, in the above example, since the printer uses a Z
step_distance of .0125, a range of 0.012500 would be considered
normal.
differ by one Z "step distance" or up to 5 microns (.005mm). A "step
distance" is
`rotation_distance/(full_steps_per_rotation*microsteps)`. The distance
between the minimum and the maximum value is called the range. So, in
the above example, since the printer uses a Z step distance of .0125,
a range of 0.012500 would be considered normal.
If the results of the test show a range value that is greater than 25
microns (.025mm) then the probe does not have sufficient accuracy for

12
klippy/extras/tmc.py
View File

@ -1,9 +1,10 @@
# Common helper code for TMC stepper drivers
#
# Copyright (C) 2018-2019 Kevin O'Connor <kevin@koconnor.net>
# Copyright (C) 2018-2020 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import logging, collections
import stepper
######################################################################
@ -263,9 +264,14 @@ class TMCMicrostepHelper:
def __init__(self, config, mcu_tmc):
self.mcu_tmc = mcu_tmc
self.fields = mcu_tmc.get_fields()
stepper_name = " ".join(config.get_name().split()[1:])
stepper_config = ms_config = config.getsection(stepper_name)
if stepper_config.get('microsteps', None, note_valid=False) is None:
# Older config format with microsteps in tmc config section
ms_config = config
steps = {'256': 0, '128': 1, '64': 2, '32': 3, '16': 4,
'8': 5, '4': 6, '2': 7, '1': 8}
mres = config.getchoice('microsteps', steps)
mres = ms_config.getchoice('microsteps', steps)
self.fields.set_field("MRES", mres)
self.fields.set_field("intpol", config.getboolean("interpolate", True))
def get_microsteps(self):
@ -287,7 +293,7 @@ def TMCStealthchopHelper(config, mcu_tmc, tmc_freq):
if velocity:
stepper_name = " ".join(config.get_name().split()[1:])
stepper_config = config.getsection(stepper_name)
step_dist = stepper_config.getfloat('step_distance', note_valid=False)
step_dist = stepper.parse_step_distance(stepper_config)
step_dist_256 = step_dist / (1 << fields.get_field("MRES"))
threshold = int(tmc_freq * step_dist_256 / velocity + .5)
fields.set_field("TPWMTHRS", max(0, min(0xfffff, threshold)))

43
klippy/stepper.py
View File

@ -183,7 +183,7 @@ def PrinterStepper(config, units_in_radians=False):
step_pin_params = ppins.lookup_pin(step_pin, can_invert=True)
dir_pin = config.get('dir_pin')
dir_pin_params = ppins.lookup_pin(dir_pin, can_invert=True)
step_dist = config.getfloat('step_distance', above=0.)
step_dist = parse_step_distance(config, units_in_radians, True)
mcu_stepper = MCU_stepper(name, step_pin_params, dir_pin_params, step_dist,
units_in_radians)
# Support for stepper enable pin handling
@ -194,6 +194,47 @@ def PrinterStepper(config, units_in_radians=False):
force_move.register_stepper(mcu_stepper)
return mcu_stepper
# Parse stepper gear_ratio config parameter
def parse_gear_ratio(config, note_valid):
gear_ratio = config.get('gear_ratio', None, note_valid=note_valid)
if gear_ratio is None:
return 1.
result = 1.
try:
gears = gear_ratio.split(',')
for gear in gears:
g1, g2 = [float(v.strip()) for v in gear.split(':')]
result *= g1 / g2
except:
raise config.error("Unable to parse gear_ratio: %s" % (gear_ratio,))
return result
# Obtain "step distance" information from a config section
def parse_step_distance(config, units_in_radians=None, note_valid=False):
if units_in_radians is None:
# Caller doesn't know if units are in radians - infer it
rd = config.get('rotation_distance', None, note_valid=False)
gr = config.get('gear_ratio', None, note_valid=False)
units_in_radians = rd is None and gr is not None
if units_in_radians:
rotation_dist = 2. * math.pi
config.get('gear_ratio', note_valid=note_valid)
else:
rotation_dist = config.getfloat('rotation_distance', None,
above=0., note_valid=note_valid)
if rotation_dist is None:
# Older config format with step_distance
return config.getfloat('step_distance', above=0., note_valid=note_valid)
# Newer config format with rotation_distance
microsteps = config.getint('microsteps', minval=1, note_valid=note_valid)
full_steps = config.getint('full_steps_per_rotation', 200, minval=1,
note_valid=note_valid)
if full_steps % 4:
raise config.error("full_steps_per_rotation invalid in section '%s'"
% (config.get_name(),))
gearing = parse_gear_ratio(config, note_valid)
return rotation_dist / (full_steps * microsteps * gearing)
######################################################################
# Stepper controlled rails

9
test/klippy/rotary_delta_calibrate.cfg
View File

@ -3,7 +3,8 @@
step_pin: ar54
dir_pin: ar55
enable_pin: !ar38
step_distance: 0.000010
microsteps: 16
gear_ratio: 107.000:16, 60:16
endstop_pin: ^ar2
homing_speed: 50
#position_endstop: 252
@ -14,14 +15,16 @@ lower_arm_length: 320.000
step_pin: ar60
dir_pin: ar61
enable_pin: !ar56
step_distance: 0.000010
microsteps: 16
gear_ratio: 107.000:16, 60:16
endstop_pin: ^ar15
[stepper_c]
step_pin: ar46
dir_pin: ar48
enable_pin: !ar62
step_distance: 0.000010
microsteps: 16
gear_ratio: 107.000:16, 60:16
endstop_pin: ^ar19
[mcu]