148 lines
6.6 KiB
Python
148 lines
6.6 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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self.steppers = [stepper.PrinterStepper(
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printer, config.getsection('stepper_' + n), n)
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for n in ['x', 'y', 'z']]
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self.max_z_velocity = config.getfloat('max_z_velocity', 9999999.9)
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self.max_z_accel = config.getfloat('max_z_accel', 9999999.9)
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self.need_motor_enable = True
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self.limits = [(1.0, -1.0)] * 3
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def set_max_jerk(self, max_xy_halt_velocity, max_velocity, max_accel):
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self.steppers[0].set_max_jerk(max_xy_halt_velocity, max_accel)
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self.steppers[1].set_max_jerk(max_xy_halt_velocity, max_accel)
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self.steppers[2].set_max_jerk(0., self.max_z_accel)
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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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for i in StepList:
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s = self.steppers[i]
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s.mcu_stepper.set_position(int(newpos[i]*s.inv_step_dist + 0.5))
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def home(self, homing_state):
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# Each axis is homed independently and in order
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for axis in homing_state.get_axes():
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s = self.steppers[axis]
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self.limits[axis] = (s.position_min, s.position_max)
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# Determine moves
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if s.homing_positive_dir:
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pos = s.position_endstop - 1.5*(
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s.position_endstop - s.position_min)
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rpos = s.position_endstop - s.homing_retract_dist
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r2pos = rpos - s.homing_retract_dist
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else:
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pos = s.position_endstop + 1.5*(
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s.position_max - s.position_endstop)
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rpos = s.position_endstop + s.homing_retract_dist
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r2pos = rpos + s.homing_retract_dist
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# Initial homing
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homepos = [None, None, None, None]
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homepos[axis] = s.position_endstop
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coord = [None, None, None, None]
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coord[axis] = pos
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homing_state.home(list(coord), homepos, [s], s.homing_speed)
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# Retract
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coord[axis] = rpos
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homing_state.retract(list(coord), s.homing_speed)
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# Home again
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coord[axis] = r2pos
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homing_state.home(
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list(coord), homepos, [s], s.homing_speed/2.0, second_home=True)
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# Set final homed position
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coord[axis] = s.position_endstop + s.get_homed_offset()*s.step_dist
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homing_state.set_homed_position(coord)
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def motor_off(self, move_time):
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self.limits = [(1.0, -1.0)] * 3
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for stepper in self.steppers:
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stepper.motor_enable(move_time, 0)
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self.need_motor_enable = True
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def _check_motor_enable(self, move_time, move):
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need_motor_enable = False
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for i in StepList:
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if move.axes_d[i]:
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self.steppers[i].motor_enable(move_time, 1)
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need_motor_enable |= self.steppers[i].need_motor_enable
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self.need_motor_enable = need_motor_enable
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def query_endstops(self, print_time):
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endstops = [(s, s.query_endstop(print_time)) for s in self.steppers]
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return [(s.name, es.query_endstop_wait()) for s, es in endstops]
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def _check_endstops(self, move):
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end_pos = move.end_pos
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for i in StepList:
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if (move.axes_d[i]
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and (end_pos[i] < self.limits[i][0]
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or end_pos[i] > self.limits[i][1])):
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if self.limits[i][0] > self.limits[i][1]:
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raise homing.EndstopMoveError(
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end_pos, "Must home axis first")
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raise homing.EndstopMoveError(end_pos)
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def check_move(self, move):
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limits = self.limits
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xpos, ypos = move.end_pos[:2]
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if (xpos < limits[0][0] or xpos > limits[0][1]
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or ypos < limits[1][0] or ypos > limits[1][1]):
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self._check_endstops(move)
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if not move.axes_d[2]:
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# Normal XY move - use defaults
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return
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# Move with Z - update velocity and accel for slower Z axis
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self._check_endstops(move)
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z_ratio = move.move_d / abs(move.axes_d[2])
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move.limit_speed(
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self.max_z_velocity * z_ratio, self.max_z_accel * z_ratio)
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def move(self, move_time, move):
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if self.need_motor_enable:
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self._check_motor_enable(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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if not move.axes_d[i]:
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continue
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mcu_stepper = self.steppers[i].mcu_stepper
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mcu_time = mcu_stepper.print_to_mcu_time(move_time)
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step_pos = mcu_stepper.commanded_position
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inv_step_dist = self.steppers[i].inv_step_dist
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step_offset = step_pos - move.start_pos[i] * inv_step_dist
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steps = move.axes_d[i] * inv_step_dist
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move_step_d = move.move_d / abs(steps)
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# Acceleration steps
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accel_multiplier = 2.0 * move_step_d * inv_accel
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if move.accel_r:
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#t = sqrt(2*pos/accel + (start_v/accel)**2) - start_v/accel
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accel_time_offset = move.start_v * inv_accel
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accel_sqrt_offset = accel_time_offset**2
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accel_steps = move.accel_r * steps
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count = mcu_stepper.step_sqrt(
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mcu_time - accel_time_offset, accel_steps, step_offset
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, accel_sqrt_offset, accel_multiplier)
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step_offset += count - accel_steps
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mcu_time += move.accel_t
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# Cruising steps
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if move.cruise_r:
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#t = pos/cruise_v
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cruise_multiplier = move_step_d * inv_cruise_v
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cruise_steps = move.cruise_r * steps
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count = mcu_stepper.step_factor(
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mcu_time, cruise_steps, step_offset, cruise_multiplier)
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step_offset += count - cruise_steps
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mcu_time += move.cruise_t
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# Deceleration steps
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if move.decel_r:
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#t = cruise_v/accel - sqrt((cruise_v/accel)**2 - 2*pos/accel)
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decel_time_offset = move.cruise_v * inv_accel
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decel_sqrt_offset = decel_time_offset**2
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decel_steps = move.decel_r * steps
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count = mcu_stepper.step_sqrt(
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mcu_time + decel_time_offset, decel_steps, step_offset
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, decel_sqrt_offset, -accel_multiplier)
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