kinematics: Add deltesian printers (#5743)

Initial push of the working deltesian kinematics after some successful tests.

Signed-off-by: Fabrice GALLET <tircown@gmail.com>

config/example-deltesian.cfg

@@ -0,0 +1,73 @@
+# This file is an example config file for deltesian style printers.
+# One may copy and edit this file to configure a new deltesian
+# printer.
+
+# DO NOT COPY THIS FILE WITHOUT CAREFULLY READING AND UPDATING IT
+# FIRST. Incorrectly configured parameters may cause damage.
+
+# See docs/Config_Reference.md for a description of parameters.
+
+[stepper_left]
+step_pin: PF0
+dir_pin: PF1
+enable_pin: !PD7
+microsteps: 16
+rotation_distance: 40
+endstop_pin: ^PE5
+homing_speed: 50
+position_endstop: 268
+arm_length: 217
+arm_x_length: 160
+
+[stepper_right]
+step_pin: PL3
+dir_pin: PL1
+enable_pin: !PK0
+microsteps: 16
+rotation_distance: 40
+endstop_pin: ^PD3
+
+[stepper_y]
+step_pin: PF6
+dir_pin: !PF7
+enable_pin: !PF2
+microsteps: 16
+rotation_distance: 40
+endstop_pin: ^PJ1
+position_endstop: 0
+position_max: 200
+
+[extruder]
+step_pin: PA4
+dir_pin: PA6
+enable_pin: !PA2
+microsteps: 16
+rotation_distance: 33.500
+nozzle_diameter: 0.500
+filament_diameter: 3.500
+heater_pin: PB4
+sensor_type: EPCOS 100K B57560G104F
+sensor_pin: PK5
+control: pid
+pid_Kp: 22.2
+pid_Ki: 1.08
+pid_Kd: 114
+min_temp: 0
+max_temp: 210
+
+[heater_bed]
+heater_pin: PH5
+sensor_type: EPCOS 100K B57560G104F
+sensor_pin: PK6
+control: watermark
+min_temp: 0
+max_temp: 110
+
+[mcu]
+serial: /dev/ttyACM0
+
+[printer]
+kinematics: deltesian
+max_velocity: 500
+max_accel: 3000
+max_z_velocity: 150

docs/Config_Reference.md

@@ -85,8 +85,7 @@ The printer section controls high level printer settings.
 kinematics:
 #   The type of printer in use. This option may be one of: cartesian,
 #   corexy, corexz, hybrid_corexy, hybrid_corexz, rotary_delta, delta,
-#   polar, winch, or none. This
+#   deltesian, polar, winch, or none. This parameter must be specified.
-#   parameter must be specified.
 max_velocity:
 #   Maximum velocity (in mm/s) of the toolhead (relative to the
 #   print). This parameter must be specified.
@@ -318,6 +317,81 @@ radius:
 #   just prior to starting a probe operation. The default is 5.
 ```
 
+### Deltesian Kinematics
+
+See [example-deltesian.cfg](../config/example-deltesian.cfg) for an
+example deltesian kinematics config file.
+
+Only parameters specific to deltesian printers are described here - see
+[common kinematic settings](#common-kinematic-settings) for available
+ parameters.
+
+```
+[printer]
+kinematics: deltesian
+max_z_velocity:
+#   For deltesian printers, this limits the maximum velocity (in mm/s) of
+#   moves with z axis movement. This setting can be used to reduce the
+#   maximum speed of up/down moves (which require a higher step rate
+#   than other moves on a deltesian printer). The default is to use
+#   max_velocity for max_z_velocity.
+#max_z_accel:
+#   This sets the maximum acceleration (in mm/s^2) of movement along
+#   the z axis. Setting this may be useful if the printer can reach higher
+#   acceleration on XY moves than Z moves (eg, when using input shaper).
+#   The default is to use max_accel for max_z_accel.
+#minimum_z_position: 0
+#   The minimum Z position that the user may command the head to move
+#   to. The default is 0.
+#min_angle: 5
+#   This represents the minimum angle (in degrees) relative to horizontal
+#   that the deltesian arms are allowed to achieve. This parameter is
+#   intended to restrict the arms from becomming completely horizontal,
+#   which would risk accidental inversion of the XZ axis. The default is 5.
+#print_width:
+#   The distance (in mm) of valid toolhead X coordinates. One may use
+#   this setting to customize the range checking of toolhead moves. If
+#   a large value is specified here then it may be possible to command
+#   the toolhead into a collision with a tower. This setting usually
+#   corresponds to bed width (in mm).
+#slow_ratio: 3
+#   The ratio used to limit velocity and acceleration on moves near the
+#   extremes of the X axis. If vertical distance divided by horizontal
+#   distance exceeds the value of slow_ratio, then velocity and
+#   acceleration are limited to half their nominal values. If vertical
+#   distance divided by horizontal distance exceeds twice the value of
+#   the slow_ratio, then velocity and acceleration are limited to one
+#   quarter of their nominal values. The default is 3.
+
+# The stepper_left section is used to describe the stepper controlling
+# the left tower. This section also controls the homing parameters
+# (homing_speed, homing_retract_dist) for all towers.
+[stepper_left]
+position_endstop:
+#   Distance (in mm) between the nozzle and the bed when the nozzle is
+#   in the center of the build area and the endstops are triggered. This
+#   parameter must be provided for stepper_left; for stepper_right this
+#   parameter defaults to the value specified for stepper_left.
+arm_length:
+#   Length (in mm) of the diagonal rod that connects the tower carriage to
+#   the print head. This parameter must be provided for stepper_left; for
+#   stepper_right, this parameter defaults to the value specified for
+#   stepper_left.
+arm_x_length:
+#   Horizontal distance between the print head and the tower when the
+#   printers is homed. This parameter must be provided for stepper_left;
+#   for stepper_right, this parameter defaults to the value specified for
+#   stepper_left.
+
+# The stepper_right section is used to desribe the stepper controlling the
+# right tower.
+[stepper_right]
+
+# The stepper_y section is used to describe the stepper controlling
+# the Y axis in a deltesian robot.
+[stepper_y]
+```
+
 ### CoreXY Kinematics
 
 See [example-corexy.cfg](../config/example-corexy.cfg) for an example

klippy/chelper/__init__.py

@@ -20,8 +20,8 @@ SOURCE_FILES = [
     'pyhelper.c', 'serialqueue.c', 'stepcompress.c', 'itersolve.c', 'trapq.c',
     'pollreactor.c', 'msgblock.c', 'trdispatch.c',
     'kin_cartesian.c', 'kin_corexy.c', 'kin_corexz.c', 'kin_delta.c',
-    'kin_polar.c', 'kin_rotary_delta.c', 'kin_winch.c', 'kin_extruder.c',
+    'kin_deltesian.c', 'kin_polar.c', 'kin_rotary_delta.c', 'kin_winch.c',
-    'kin_shaper.c',
+    'kin_extruder.c', 'kin_shaper.c',
 ]
 DEST_LIB = "c_helper.so"
 OTHER_FILES = [
@@ -117,6 +117,11 @@ defs_kin_delta = """
         , double tower_x, double tower_y);
 """
 
+defs_kin_deltesian = """
+    struct stepper_kinematics *deltesian_stepper_alloc(double arm2
+        , double arm_x);
+"""
+
 defs_kin_polar = """
     struct stepper_kinematics *polar_stepper_alloc(char type);
 """
@@ -205,8 +210,8 @@ defs_all = [
     defs_pyhelper, defs_serialqueue, defs_std, defs_stepcompress,
     defs_itersolve, defs_trapq, defs_trdispatch,
     defs_kin_cartesian, defs_kin_corexy, defs_kin_corexz, defs_kin_delta,
-    defs_kin_polar, defs_kin_rotary_delta, defs_kin_winch, defs_kin_extruder,
+    defs_kin_deltesian, defs_kin_polar, defs_kin_rotary_delta, defs_kin_winch,
-    defs_kin_shaper,
+    defs_kin_extruder, defs_kin_shaper,
 ]
 
 # Update filenames to an absolute path

klippy/chelper/kin_deltesian.c

@@ -0,0 +1,41 @@
+// Deltesian kinematics stepper pulse time generation
+//
+// Copyright (C) 2022  Fabrice Gallet <tircown@gmail.com>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include <math.h> // sqrt
+#include <stddef.h> // offsetof
+#include <stdlib.h> // malloc
+#include <string.h> // memset
+#include "compiler.h" // __visible
+#include "itersolve.h" // struct stepper_kinematics
+#include "trapq.h" // move_get_coord
+
+struct deltesian_stepper {
+    struct stepper_kinematics sk;
+    double arm2, arm_x;
+};
+
+static double
+deltesian_stepper_calc_position(struct stepper_kinematics *sk, struct move *m
+                            , double move_time)
+{
+    struct deltesian_stepper *ds = container_of(
+                sk, struct deltesian_stepper, sk);
+    struct coord c = move_get_coord(m, move_time);
+    double dx = c.x - ds->arm_x;
+    return sqrt(ds->arm2 - dx*dx) + c.z;
+}
+
+struct stepper_kinematics * __visible
+deltesian_stepper_alloc(double arm2, double arm_x)
+{
+    struct deltesian_stepper *ds = malloc(sizeof(*ds));
+    memset(ds, 0, sizeof(*ds));
+    ds->arm2 = arm2;
+    ds->arm_x = arm_x;
+    ds->sk.calc_position_cb = deltesian_stepper_calc_position;
+    ds->sk.active_flags = AF_X | AF_Z;
+    return &ds->sk;
+}

klippy/kinematics/deltesian.py

@@ -0,0 +1,184 @@
+# Code for handling the kinematics of deltesian robots
+#
+# Copyright (C) 2022  Fabrice Gallet <tircown@gmail.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import math, logging
+import stepper
+
+# Slow moves once the ratio of tower to XY movement exceeds SLOW_RATIO
+SLOW_RATIO = 3.
+
+# Minimum angle with the horizontal for the arm to not exceed - in degrees
+MIN_ANGLE = 5.
+
+class DeltesianKinematics:
+    def __init__(self, toolhead, config):
+        self.rails = [None] * 3
+        stepper_configs = [config.getsection('stepper_' + s)
+                                    for s in ['left', 'right', 'y']]
+        self.rails[0] = stepper.PrinterRail(
+            stepper_configs[0], need_position_minmax = False)
+        def_pos_es = self.rails[0].get_homing_info().position_endstop
+        self.rails[1] = stepper.PrinterRail(
+            stepper_configs[1], need_position_minmax = False,
+            default_position_endstop = def_pos_es)
+        self.rails[2] = stepper.LookupMultiRail(stepper_configs[2])
+        arm_x = self.arm_x = [None] * 2
+        arm_x[0] = stepper_configs[0].getfloat('arm_x_length', above=0.)
+        arm_x[1] = stepper_configs[1].getfloat('arm_x_length', arm_x[0],
+                                                above=0.)
+        arm = [None] * 2
+        arm[0] = stepper_configs[0].getfloat('arm_length', above=arm_x[0])
+        arm[1] = stepper_configs[1].getfloat('arm_length', arm[0],
+                                              above=arm_x[1])
+        arm2 = self.arm2 = [a**2 for a in arm]
+        self.rails[0].setup_itersolve(
+            'deltesian_stepper_alloc', arm2[0], -arm_x[0])
+        self.rails[1].setup_itersolve(
+            'deltesian_stepper_alloc', arm2[1], arm_x[1])
+        self.rails[2].setup_itersolve('cartesian_stepper_alloc', b'y')
+        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)
+        self.limits = [(1.0, -1.0)] * 3
+        # X axis limits
+        min_angle = config.getfloat('min_angle', MIN_ANGLE,
+                                    minval=0., maxval=90.)
+        cos_angle = math.cos(math.radians(min_angle))
+        x_kin_min = math.ceil( -min(arm_x[0], cos_angle * arm[1] - arm_x[1]))
+        x_kin_max = math.floor( min(arm_x[1], cos_angle * arm[0] - arm_x[0]))
+        x_kin_range = min(x_kin_max - x_kin_min, x_kin_max * 2, -x_kin_min * 2)
+        print_width = config.getfloat('print_width', None, minval=0.,
+                                      maxval=x_kin_range)
+        if print_width:
+            self.limits[0] = (-print_width * 0.5, print_width * 0.5)
+        else:
+            self.limits[0] = (x_kin_min, x_kin_max)
+        # Y axis limits
+        self.limits[1] = self.rails[2].get_range()
+        # Z axis limits
+        pmax = [r.get_homing_info().position_endstop for r in self.rails[:2]]
+        self._abs_endstop = [p + math.sqrt(a2 - ax**2) for p, a2, ax
+                    in zip( pmax, arm2, arm_x )]
+        self.home_z = self._actuator_to_cartesian(self._abs_endstop)[1]
+        z_max = min([self._pillars_z_max(x) for x in self.limits[0]])
+        z_min = config.getfloat('minimum_z_position', 0, maxval=z_max)
+        self.limits[2] = (z_min, z_max)
+        # Limit the speed/accel if is is at the extreme values of the x axis
+        slow_ratio = config.getfloat('slow_ratio', SLOW_RATIO, minval=0.)
+        self.slow_x2 = self.very_slow_x2 = None
+        if slow_ratio > 0.:
+            sr2 = slow_ratio ** 2
+            self.slow_x2 = min([math.sqrt((sr2 * a2) / (sr2 + 1))
+                        - axl for a2, axl in zip(arm2, arm_x)]) ** 2
+            self.very_slow_x2 = min([math.sqrt((2 * sr2 * a2) / (2 * sr2 + 1))
+                        - axl for a2, axl in zip(arm2, arm_x)]) ** 2
+            logging.info("Deltesian kinematics: moves slowed past %.2fmm"
+                         " and %.2fmm"
+                         % (math.sqrt(self.slow_x2),
+                            math.sqrt(self.very_slow_x2)))
+        # 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.axes_min = toolhead.Coord(*[l[0] for l in self.limits], e=0.)
+        self.axes_max = toolhead.Coord(*[l[1] for l in self.limits], e=0.)
+        self.homed_axis = [False] * 3
+        self.set_position([0., 0., 0.], ())
+    def get_steppers(self):
+        return [s for rail in self.rails for s in rail.get_steppers()]
+    def _actuator_to_cartesian(self, sp):
+        arm_x, arm2 = self.arm_x, self.arm2
+        dx, dz = sum(arm_x), sp[1] - sp[0]
+        pivots = math.sqrt(dx**2 + dz**2)
+        # Trilateration w/ reference frame along left to right pivots
+        xt = (pivots**2 + arm2[0] - arm2[1]) / (2 * pivots)
+        zt = math.sqrt(arm2[0] - xt**2)
+        # Rotation and translation of the reference frame
+        x = xt * dx / pivots + zt * dz / pivots - arm_x[0]
+        z = xt * dz / pivots - zt * dx / pivots + sp[0]
+        return [x, z]
+    def _pillars_z_max(self, x):
+        arm_x, arm2 = self.arm_x, self.arm2
+        dz = (math.sqrt(arm2[0] - (arm_x[0] + x)**2),
+              math.sqrt(arm2[1] - (arm_x[1] - x)**2))
+        return min([o - z for o, z in zip(self._abs_endstop, dz)])
+    def calc_position(self, stepper_positions):
+        sp = [stepper_positions[rail.get_name()] for rail in self.rails]
+        x, z = self._actuator_to_cartesian(sp[:2])
+        return [x, sp[2], z]
+    def set_position(self, newpos, homing_axes):
+        for rail in self.rails:
+            rail.set_position(newpos)
+        for n in homing_axes:
+            self.homed_axis[n] = True
+    def home(self, homing_state):
+        homing_axes = homing_state.get_axes()
+        home_xz = 0 in homing_axes or 2 in homing_axes
+        home_y = 1 in homing_axes
+        forceaxes = ([0, 1, 2] if (home_xz and home_y) else
+                     [0, 2] if home_xz else [1] if home_y else [])
+        homing_state.set_axes(forceaxes)
+        homepos = [None] * 4
+        if home_xz:
+            homing_state.set_axes([0, 1, 2] if home_y else [0, 2])
+            homepos[0], homepos[2] = 0., self.home_z
+            forcepos = list(homepos)
+            dz2 = [(a2 - ax ** 2) for a2, ax in zip(self.arm2, self.arm_x)]
+            forcepos[2] = -1.5 * math.sqrt(max(dz2))
+            homing_state.home_rails(self.rails[:2], forcepos, homepos)
+        if home_y:
+            position_min, position_max = self.rails[2].get_range()
+            hi = self.rails[2].get_homing_info()
+            homepos[1] = hi.position_endstop
+            forcepos = list(homepos)
+            if hi.positive_dir:
+                forcepos[1] -= 1.5 * (hi.position_endstop - position_min)
+            else:
+                forcepos[1] += 1.5 * (position_max - hi.position_endstop)
+            homing_state.home_rails([self.rails[2]], forcepos, homepos)
+    def _motor_off(self, print_time):
+        self.homed_axis = [False] * 3
+    def check_move(self, move):
+        limits = list(map(list, self.limits))
+        spos, epos = move.start_pos, move.end_pos
+        homing_move = False
+        if epos[0] == 0. and epos[2] == self.home_z and not move.axes_d[1]:
+            # Identify a homing move
+            homing_move = True
+        elif epos[2] > limits[2][1]:
+            # Moves at the very top - adapt limits depending on the X position
+            limits[2][1] = self._pillars_z_max(epos[0])
+        for i in (i for i, v in enumerate(move.axes_d[:3]) if v):
+            if not self.homed_axis[i]:
+                raise move.move_error("Must home axis first")
+            # Move out of range - verify not a homing move
+            if epos[i] < limits[i][0] or epos[i] > limits[i][1]:
+                if not homing_move:
+                    raise move.move_error()
+        if move.axes_d[2]:
+            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)
+        # Limit the speed/accel if is is at the extreme values of the x axis
+        if move.axes_d[0] and self.slow_x2 and self.very_slow_x2:
+            move_x2 = max(spos[0] ** 2, epos[0] ** 2)
+            if move_x2 > self.very_slow_x2:
+                move.limit_speed(self.max_velocity *0.25, self.max_accel *0.25)
+            elif move_x2 > self.slow_x2:
+                move.limit_speed(self.max_velocity *0.50, self.max_accel *0.50)
+    def get_status(self, eventtime):
+        axes = [a for a, b in zip("xyz", self.homed_axis) if b]
+        return {
+            'homed_axes': "".join(axes),
+            'axis_minimum': self.axes_min,
+            'axis_maximum': self.axes_max,
+        }
+
+def load_kinematics(toolhead, config):
+    return DeltesianKinematics(toolhead, config)

test/klippy/printers.test

@@ -9,6 +9,7 @@ CONFIG ../../config/example-corexz.cfg
 CONFIG ../../config/example-hybrid-corexy.cfg
 CONFIG ../../config/example-hybrid-corexz.cfg
 CONFIG ../../config/example-delta.cfg
+CONFIG ../../config/example-deltesian.cfg
 CONFIG ../../config/example-rotary-delta.cfg
 CONFIG ../../config/example-winch.cfg