corexz: Add CoreXZ kinematics (#3129)

Add a CoreXZ kinematics

Signed-off-by: Maks Zolin <mzolin@vorondesign.com>

klippy/kinematics/corexz.py

@@ -0,0 +1,101 @@
+# Code for handling the kinematics of corexz robots
+#
+# Copyright (C) 2020  Maks Zolin <mzolin@vorondesign.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import logging, math
+import stepper, homing
+
+class CoreXZKinematics:
+    def __init__(self, toolhead, config):
+        # Setup axis rails
+        self.rails = [ stepper.PrinterRail(config.getsection('stepper_x')),
+                       stepper.PrinterRail(config.getsection('stepper_y')),
+                       stepper.PrinterRail(config.getsection('stepper_z')) ]
+        self.rails[0].get_endstops()[0][0].add_stepper(
+            self.rails[2].get_steppers()[0])
+        self.rails[2].get_endstops()[0][0].add_stepper(
+            self.rails[0].get_steppers()[0])
+        self.rails[0].setup_itersolve('corexz_stepper_alloc', '+')
+        self.rails[1].setup_itersolve('cartesian_stepper_alloc', 'y')
+        self.rails[2].setup_itersolve('corexz_stepper_alloc', '-')
+        for s in self.get_steppers():
+            s.set_trapq(toolhead.get_trapq())
+            toolhead.register_step_generator(s.generate_steps)
+        config.get_printer().register_event_handler("stepper_enable:motor_off",
+                                                    self._motor_off)
+        # 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.limits = [(1.0, -1.0)] * 3
+        # Setup stepper max halt velocity
+        max_halt_velocity = toolhead.get_max_axis_halt()
+        max_xy_halt_velocity = max_halt_velocity * math.sqrt(2.)
+        max_xy_accel = max_accel * math.sqrt(2.)
+        self.rails[0].set_max_jerk(max_xy_halt_velocity, max_xy_accel)
+        self.rails[1].set_max_jerk(max_xy_halt_velocity, max_xy_accel)
+        self.rails[2].set_max_jerk(max_xy_halt_velocity, max_xy_accel)
+    def get_steppers(self):
+        return [s for rail in self.rails for s in rail.get_steppers()]
+    def calc_tag_position(self):
+        pos = [rail.get_tag_position() for rail in self.rails]
+        return [0.5 * (pos[0] + pos[2]), pos[1], 0.5 * (pos[0] - pos[2])]
+    def set_position(self, newpos, homing_axes):
+        for i, rail in enumerate(self.rails):
+            rail.set_position(newpos)
+            if i in homing_axes:
+                self.limits[i] = rail.get_range()
+    def note_z_not_homed(self):
+        # Helper for Safe Z Home
+        self.limits[2] = (1.0, -1.0)
+    def home(self, homing_state):
+        # Each axis is homed independently and in order
+        for axis in homing_state.get_axes():
+            rail = self.rails[axis]
+            # Determine movement
+            position_min, position_max = rail.get_range()
+            hi = rail.get_homing_info()
+            homepos = [None, None, None, None]
+            homepos[axis] = hi.position_endstop
+            forcepos = list(homepos)
+            if hi.positive_dir:
+                forcepos[axis] -= 1.5 * (hi.position_endstop - position_min)
+            else:
+                forcepos[axis] += 1.5 * (position_max - hi.position_endstop)
+            # Perform homing
+            homing_state.home_rails([rail], forcepos, homepos)
+    def _motor_off(self, print_time):
+        self.limits = [(1.0, -1.0)] * 3
+    def _check_endstops(self, move):
+        end_pos = move.end_pos
+        for i in (0, 1, 2):
+            if (move.axes_d[i]
+                and (end_pos[i] < self.limits[i][0]
+                     or end_pos[i] > self.limits[i][1])):
+                if self.limits[i][0] > self.limits[i][1]:
+                    raise homing.EndstopMoveError(
+                        end_pos, "Must home axis first")
+                raise homing.EndstopMoveError(end_pos)
+    def check_move(self, move):
+        limits = self.limits
+        xpos, ypos = move.end_pos[:2]
+        if (xpos < limits[0][0] or xpos > limits[0][1]
+            or ypos < limits[1][0] or ypos > limits[1][1]):
+            self._check_endstops(move)
+        if not move.axes_d[2]:
+            # Normal XY move - use defaults
+            return
+        # Move with Z - update velocity and accel for slower Z axis
+        self._check_endstops(move)
+        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 get_status(self, eventtime):
+        axes = [a for a, (l, h) in zip("xyz", self.limits) if l <= h]
+        return {'homed_axes': "".join(axes)}
+
+def load_kinematics(toolhead, config):
+    return CoreXZKinematics(toolhead, config)