87 lines
3.8 KiB
Python
87 lines
3.8 KiB
Python
# Code for handling the kinematics of cartesian robots
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#
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# Copyright (C) 2016 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 logging
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import stepper, homing
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StepList = (0, 1, 2)
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class CartKinematics:
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def __init__(self, printer, config):
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steppers = ['stepper_x', 'stepper_y', 'stepper_z']
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self.steppers = [stepper.PrinterStepper(printer, config.getsection(n))
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for n in steppers]
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self.stepper_pos = [0, 0, 0]
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def build_config(self):
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for stepper in self.steppers:
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stepper.build_config()
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def set_position(self, newpos):
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self.stepper_pos = [int(newpos[i]*self.steppers[i].inv_step_dist + 0.5)
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for i in StepList]
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def get_max_xy_speed(self):
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max_xy_speed = min(s.max_velocity for s in self.steppers[:2])
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max_xy_accel = min(s.max_accel for s in self.steppers[:2])
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return max_xy_speed, max_xy_accel
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def get_max_speed(self, axes_d, move_d):
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# Calculate max speed and accel for a given move
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velocity_factor = min([self.steppers[i].max_velocity / abs(axes_d[i])
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for i in StepList if axes_d[i]])
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accel_factor = min([self.steppers[i].max_accel / abs(axes_d[i])
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for i in StepList if axes_d[i]])
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return velocity_factor * move_d, accel_factor * move_d
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def home(self, toolhead, axis):
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# Each axis is homed independently and in order
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homing_state = homing.Homing(toolhead, self.steppers) # XXX
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for a in axis:
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homing_state.plan_home(a)
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return homing_state
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def motor_off(self, move_time):
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for stepper in self.steppers:
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stepper.motor_enable(move_time, 0)
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def move(self, move_time, move):
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inv_accel = 1. / move.accel
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inv_cruise_v = 1. / move.cruise_v
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for i in StepList:
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new_step_pos = int(move.pos[i]*self.steppers[i].inv_step_dist + 0.5)
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steps = new_step_pos - self.stepper_pos[i]
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if not steps:
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continue
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self.stepper_pos[i] = new_step_pos
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sdir = 0
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if steps < 0:
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sdir = 1
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steps = -steps
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clock_offset, clock_freq, so = self.steppers[i].prep_move(
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sdir, move_time)
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step_dist = move.move_d / steps
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step_offset = 0.5
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# Acceleration steps
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#t = sqrt(2*pos/accel + (start_v/accel)**2) - start_v/accel
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accel_clock_offset = move.start_v * inv_accel * clock_freq
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accel_sqrt_offset = accel_clock_offset**2
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accel_multiplier = 2.0 * step_dist * inv_accel * clock_freq**2
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accel_steps = move.accel_r * steps
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step_offset = so.step_sqrt(
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accel_steps, step_offset, clock_offset - accel_clock_offset
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, accel_sqrt_offset, accel_multiplier)
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clock_offset += move.accel_t * clock_freq
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# Cruising steps
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#t = pos/cruise_v
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cruise_multiplier = step_dist * inv_cruise_v * clock_freq
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cruise_steps = move.cruise_r * steps
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step_offset = so.step_factor(
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cruise_steps, step_offset, clock_offset, cruise_multiplier)
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clock_offset += move.cruise_t * clock_freq
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# Deceleration steps
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#t = cruise_v/accel - sqrt((cruise_v/accel)**2 - 2*pos/accel)
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decel_clock_offset = move.cruise_v * inv_accel * clock_freq
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decel_sqrt_offset = decel_clock_offset**2
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decel_steps = move.decel_r * steps
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so.step_sqrt(
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decel_steps, step_offset, clock_offset + decel_clock_offset
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, decel_sqrt_offset, -accel_multiplier)
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