klipper/klippy/cartesian.py

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# Code for handling the kinematics of cartesian robots
#
# Copyright (C) 2016 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import logging
import stepper, homing
StepList = (0, 1, 2)
class CartKinematics:
def __init__(self, printer, config):
steppers = ['stepper_x', 'stepper_y', 'stepper_z']
self.steppers = [stepper.PrinterStepper(printer, config.getsection(n))
for n in steppers]
self.stepper_pos = [0, 0, 0]
def build_config(self):
for stepper in self.steppers[:2]:
stepper.set_max_jerk(0.005 * stepper.max_accel) # XXX
for stepper in self.steppers:
stepper.build_config()
def set_position(self, newpos):
self.stepper_pos = [int(newpos[i]*self.steppers[i].inv_step_dist + 0.5)
for i in StepList]
def get_max_xy_speed(self):
max_xy_speed = min(s.max_velocity for s in self.steppers[:2])
max_xy_accel = min(s.max_accel for s in self.steppers[:2])
return max_xy_speed, max_xy_accel
def get_max_speed(self, axes_d, move_d):
# Calculate max speed and accel for a given move
velocity_factor = min([self.steppers[i].max_velocity / abs(axes_d[i])
for i in StepList if axes_d[i]])
accel_factor = min([self.steppers[i].max_accel / abs(axes_d[i])
for i in StepList if axes_d[i]])
return velocity_factor * move_d, accel_factor * move_d
def get_homed_position(self):
return [s.get_homed_position() for s in self.steppers]
def home(self, toolhead, axes):
# Each axis is homed independently and in order
homing_state = homing.Homing(toolhead, axes)
for axis in axes:
s = self.steppers[axis]
# Determine moves
if s.homing_positive_dir:
pos = s.position_endstop + 1.5*(
s.position_min - s.position_endstop)
rpos = s.position_endstop - s.homing_retract_dist
r2pos = rpos - s.homing_retract_dist
else:
pos = s.position_endstop + 1.5*(
s.position_max - s.position_endstop)
rpos = s.position_endstop + s.homing_retract_dist
r2pos = rpos + s.homing_retract_dist
# Initial homing
homepos = [None, None, None, None]
homepos[axis] = s.position_endstop
coord = [None, None, None, None]
coord[axis] = pos
homing_state.plan_home(list(coord), homepos, [s], s.homing_speed)
# Retract
coord[axis] = rpos
homing_state.plan_move(list(coord), s.homing_speed)
# Home again
coord[axis] = r2pos
homing_state.plan_home(list(coord), homepos, [s], s.homing_speed/2.0)
return homing_state
def motor_off(self, move_time):
for stepper in self.steppers:
stepper.motor_enable(move_time, 0)
def move(self, move_time, move):
inv_accel = 1. / move.accel
inv_cruise_v = 1. / move.cruise_v
for i in StepList:
new_step_pos = int(move.pos[i]*self.steppers[i].inv_step_dist + 0.5)
steps = new_step_pos - self.stepper_pos[i]
if not steps:
continue
self.stepper_pos[i] = new_step_pos
sdir = 0
if steps < 0:
sdir = 1
steps = -steps
clock_offset, clock_freq, so = self.steppers[i].prep_move(
sdir, move_time)
step_dist = move.move_d / steps
step_offset = 0.5
# Acceleration steps
#t = sqrt(2*pos/accel + (start_v/accel)**2) - start_v/accel
accel_clock_offset = move.start_v * inv_accel * clock_freq
accel_sqrt_offset = accel_clock_offset**2
accel_multiplier = 2.0 * step_dist * inv_accel * clock_freq**2
accel_steps = move.accel_r * steps
step_offset = so.step_sqrt(
accel_steps, step_offset, clock_offset - accel_clock_offset
, accel_sqrt_offset, accel_multiplier)
clock_offset += move.accel_t * clock_freq
# Cruising steps
#t = pos/cruise_v
cruise_multiplier = step_dist * inv_cruise_v * clock_freq
cruise_steps = move.cruise_r * steps
step_offset = so.step_factor(
cruise_steps, step_offset, clock_offset, cruise_multiplier)
clock_offset += move.cruise_t * clock_freq
# Deceleration steps
#t = cruise_v/accel - sqrt((cruise_v/accel)**2 - 2*pos/accel)
decel_clock_offset = move.cruise_v * inv_accel * clock_freq
decel_sqrt_offset = decel_clock_offset**2
decel_steps = move.decel_r * steps
so.step_sqrt(
decel_steps, step_offset, clock_offset + decel_clock_offset
, decel_sqrt_offset, -accel_multiplier)