polar: Experimental support for polar kinematics

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 131 insertions, 0 deletions

diff --git a/klippy/kinematics/polar.py b/klippy/kinematics/polar.py
new file mode 100644
index 00000000..2930152c
--- /dev/null
+++ b/klippy/kinematics/polar.py
@@ -0,0 +1,131 @@
+# Code for handling the kinematics of polar robots
+#
+# Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import logging, math
+import stepper, homing
+
+class PolarKinematics:
+    def __init__(self, toolhead, config):
+        # Setup axis steppers
+        stepper_bed = stepper.PrinterStepper(config.getsection('stepper_bed'))
+        rail_arm = stepper.PrinterRail(config.getsection('stepper_arm'))
+        rail_z = stepper.LookupMultiRail(config.getsection('stepper_z'))
+        stepper_bed.setup_itersolve('polar_stepper_alloc', 'a')
+        rail_arm.setup_itersolve('polar_stepper_alloc', 'r')
+        rail_z.setup_itersolve('cartesian_stepper_alloc', 'z')
+        self.rails = [rail_arm, rail_z]
+        self.steppers = [stepper_bed] + [ s for r in self.rails
+                                          for s in r.get_steppers() ]
+        # Setup boundary checks
+        max_velocity, max_accel = toolhead.get_max_velocity()
+        self.max_z_velocity = config.getfloat(
+            'max_z_velocity', max_velocity, above=0., maxval=max_velocity)
+        self.max_z_accel = config.getfloat(
+            'max_z_accel', max_accel, above=0., maxval=max_accel)
+        self.need_motor_enable = True
+        self.limit_z = [(1.0, -1.0)]
+        self.limit_xy2 = -1.
+        # Setup stepper max halt velocity
+        max_halt_velocity = toolhead.get_max_axis_halt()
+        stepper_bed.set_max_jerk(max_halt_velocity, max_accel)
+        rail_arm.set_max_jerk(max_halt_velocity, max_accel)
+        rail_z.set_max_jerk(max_halt_velocity, max_accel)
+    def get_steppers(self, flags=""):
+        if flags == "Z":
+            return self.rails[1].get_steppers()
+        return list(self.steppers)
+    def calc_position(self):
+        bed_angle = self.steppers[0].get_commanded_position()
+        arm_pos = self.rails[0].get_commanded_position()
+        z_pos = self.rails[1].get_commanded_position()
+        return [math.cos(bed_angle) * arm_pos, math.sin(bed_angle) * arm_pos,
+                z_pos]
+    def set_position(self, newpos, homing_axes):
+        for s in self.steppers:
+            s.set_position(newpos)
+        if 2 in homing_axes:
+            self.limit_z = self.rails[1].get_range()
+        if 0 in homing_axes and 1 in homing_axes:
+            self.limit_xy2 = self.rails[0].get_range()[1]**2
+    def _home_axis(self, homing_state, axis, rail):
+        # Determine movement
+        position_min, position_max = rail.get_range()
+        hi = rail.get_homing_info()
+        homepos = [None, None, None, None]
+        homepos[axis] = hi.position_endstop
+        if axis == 0:
+            homepos[1] = 0.
+        forcepos = list(homepos)
+        if hi.positive_dir:
+            forcepos[axis] -= hi.position_endstop - position_min
+        else:
+            forcepos[axis] += position_max - hi.position_endstop
+        # Perform homing
+        limit_speed = None
+        if axis == 2:
+            limit_speed = self.max_z_velocity
+        homing_state.home_rails([rail], forcepos, homepos, limit_speed)
+    def home(self, homing_state):
+        # Always home XY together
+        homing_axes = homing_state.get_axes()
+        home_xy = 0 in homing_axes or 1 in homing_axes
+        home_z = 2 in homing_axes
+        updated_axes = []
+        if home_xy:
+            updated_axes = [0, 1]
+        if home_z:
+            updated_axes.append(2)
+        homing_state.set_axes(updated_axes)
+        # Do actual homing
+        if home_xy:
+            self._home_axis(homing_state, 0, self.rails[0])
+        if home_z:
+            self._home_axis(homing_state, 2, self.rails[1])
+    def motor_off(self, print_time):
+        self.limit_z = [(1.0, -1.0)]
+        self.limit_xy2 = -1.
+        for s in self.steppers:
+            s.motor_enable(print_time, 0)
+        self.need_motor_enable = True
+    def _check_motor_enable(self, print_time, move):
+        if move.axes_d[0] or move.axes_d[1]:
+            self.steppers[0].motor_enable(print_time, 1)
+            self.rails[0].motor_enable(print_time, 1)
+        if move.axes_d[2]:
+            self.rails[1].motor_enable(print_time, 1)
+        need_motor_enable = not self.steppers[0].is_motor_enabled()
+        for rail in self.rails:
+            need_motor_enable |= not rail.is_motor_enabled()
+        self.need_motor_enable = need_motor_enable
+    def check_move(self, move):
+        end_pos = move.end_pos
+        xy2 = end_pos[0]**2 + end_pos[1]**2
+        if xy2 > self.limit_xy2:
+            if self.limit_xy2 < 0.:
+                raise homing.EndstopMoveError(end_pos, "Must home axis first")
+            raise homing.EndstopMoveError(end_pos)
+        if move.axes_d[2]:
+            if end_pos[2] < self.limit_z[0] or end_pos[2] > self.limit_z[1]:
+                if self.limit_z[0] > self.limit_z[1]:
+                    raise homing.EndstopMoveError(
+                        end_pos, "Must home axis first")
+                raise homing.EndstopMoveError(end_pos)
+            # Move with Z - update velocity and accel for slower Z axis
+            z_ratio = move.move_d / abs(move.axes_d[2])
+            move.limit_speed(
+                self.max_z_velocity * z_ratio, self.max_z_accel * z_ratio)
+    def move(self, print_time, move):
+        if self.need_motor_enable:
+            self._check_motor_enable(print_time, move)
+        axes_d = move.axes_d
+        cmove = move.cmove
+        if axes_d[0] or axes_d[1]:
+            self.steppers[0].step_itersolve(cmove)
+            self.rails[0].step_itersolve(cmove)
+        if axes_d[2]:
+            self.rails[1].step_itersolve(cmove)
+
+def load_kinematics(toolhead, config):
+    return PolarKinematics(toolhead, config)