polar: Experimental support for polar kinematics

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

config/example-polar.cfg

@@ -0,0 +1,86 @@
+# This file serves as documentation for config parameters of "polar"
+# style printers. One may copy and edit this file to configure a new
+# polar printer.
+
+# POLAR KINEMATICS ARE A WORK IN PROGRESS. Moves around the 0,0
+# position are known to not work properly. Moves to a negative Y
+# coordinate from a positive Y coordinate (and vice-versa) when the
+# head is at a negative X coordinate also do not work properly.
+
+# Only parameters unique to polar printers are described here - see
+# the "example.cfg" file for description of common config parameters.
+
+# The stepper_bed section is used to describe the stepper controlling
+# the bed.
+[stepper_bed]
+step_pin: ar54
+dir_pin: ar55
+enable_pin: !ar38
+step_distance: 0.000981748
+#   On a polar printer the step_distance is the amount each step pulse
+#   moves the bed in radians (for example, a 1.8 degree stepper with
+#   16 micro-steps would be 1.8 / 360 * pi / 16 == 0.000981748). This
+#   parameter must be provided.
+
+# The stepper_arm section is used to describe the stepper controlling
+# the carriage on the arm.
+[stepper_arm]
+step_pin: ar60
+dir_pin: ar61
+enable_pin: !ar56
+step_distance: .01
+endstop_pin: ^ar14
+position_endstop: 300
+position_max: 300
+homing_speed: 50
+
+# The stepper_z section is used to describe the stepper controlling
+# the Z axis.
+[stepper_z]
+step_pin: ar46
+dir_pin: ar48
+enable_pin: !ar62
+step_distance: .0025
+endstop_pin: ^ar18
+position_endstop: 0.5
+position_max: 200
+
+[extruder]
+step_pin: ar26
+dir_pin: ar28
+enable_pin: !ar24
+step_distance: .0022
+nozzle_diameter: 0.400
+filament_diameter: 1.750
+heater_pin: ar10
+sensor_type: ATC Semitec 104GT-2
+sensor_pin: analog13
+control: pid
+pid_Kp: 22.2
+pid_Ki: 1.08
+pid_Kd: 114
+min_temp: 0
+max_temp: 250
+
+[heater_bed]
+heater_pin: ar8
+sensor_type: EPCOS 100K B57560G104F
+sensor_pin: analog14
+control: watermark
+min_temp: 0
+max_temp: 130
+
+[fan]
+pin: ar9
+
+[mcu]
+serial: /dev/ttyACM0
+pin_map: arduino
+
+[printer]
+kinematics: polar
+#   This option must be "polar" for polar printers.
+max_velocity: 300
+max_accel: 3000
+max_z_velocity: 25
+max_z_accel: 30

klippy/chelper/__init__.py

@@ -16,7 +16,8 @@
                " -o %s %s")
 SOURCE_FILES = [
     'pyhelper.c', 'serialqueue.c', 'stepcompress.c', 'itersolve.c',
-    'kin_cartesian.c', 'kin_corexy.c', 'kin_delta.c', 'kin_extruder.c'
+    'kin_cartesian.c', 'kin_corexy.c', 'kin_delta.c', 'kin_polar.c',
+    'kin_extruder.c',
 ]
 DEST_LIB = "c_helper.so"
 OTHER_FILES = [
@@ -70,6 +71,10 @@
         , double tower_x, double tower_y);
 """
 
+defs_kin_polar = """
+    struct stepper_kinematics *polar_stepper_alloc(char type);
+"""
+
 defs_kin_extruder = """
     struct stepper_kinematics *extruder_stepper_alloc(void);
     void extruder_move_fill(struct move *m, double print_time
@@ -116,7 +121,8 @@
 
 defs_all = [
     defs_pyhelper, defs_serialqueue, defs_std, defs_stepcompress, defs_itersolve,
-    defs_kin_cartesian, defs_kin_corexy, defs_kin_delta, defs_kin_extruder
+    defs_kin_cartesian, defs_kin_corexy, defs_kin_delta, defs_kin_polar,
+    defs_kin_extruder
 ]
 
 # Return the list of file modification times

klippy/chelper/kin_polar.c

@@ -0,0 +1,41 @@
+// Polar kinematics stepper pulse time generation
+//
+// Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include <math.h> // sqrt
+#include <stdlib.h> // malloc
+#include <string.h> // memset
+#include "compiler.h" // __visible
+#include "itersolve.h" // struct stepper_kinematics
+
+static double
+polar_stepper_radius_calc_position(struct stepper_kinematics *sk, struct move *m
+                                   , double move_time)
+{
+    struct coord c = move_get_coord(m, move_time);
+    return sqrt(c.x*c.x + c.y*c.y);
+}
+
+static double
+polar_stepper_angle_calc_position(struct stepper_kinematics *sk, struct move *m
+                                  , double move_time)
+{
+    struct coord c = move_get_coord(m, move_time);
+    // XXX - handle x==y==0
+    // XXX - handle angle wrapping
+    return atan2(c.y, c.x);
+}
+
+struct stepper_kinematics * __visible
+polar_stepper_alloc(char type)
+{
+    struct stepper_kinematics *sk = malloc(sizeof(*sk));
+    memset(sk, 0, sizeof(*sk));
+    if (type == 'r')
+        sk->calc_position = polar_stepper_radius_calc_position;
+    else if (type == 'a')
+        sk->calc_position = polar_stepper_angle_calc_position;
+    return sk;
+}

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)

test/klippy/polar.test

@@ -0,0 +1,32 @@
+# Test case for basic movement on polar printers
+CONFIG ../../config/example-polar.cfg
+DICTIONARY atmega2560-16mhz.dict
+
+; Start by homing the printer.
+G28
+G90
+G1 F6000
+
+; Z / X / Y moves
+G1 Z1
+G1 X1
+G1 Y1
+
+; Delayed moves
+G1 Y2
+G4 P100
+G1 Y1.5
+M400
+G1 Y1
+
+; diagonal moves
+G1 X10 Y0
+G1 X1 Z2
+G1 X0 Y1 Z1
+
+; extrude only moves
+G1 E1
+G1 E0
+
+; regular extrude move
+G1 X10 Y0 E.01