path: root/klippy/kinematics/rotary_delta.py

# Code for handling the kinematics of rotary delta robots
#
# Copyright (C) 2019-2021  Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
import math, logging
import stepper, mathutil, chelper


class RotaryDeltaKinematics:
    def __init__(self, toolhead, config):
        # Setup tower rails
        stepper_configs = [config.getsection("stepper_" + a) for a in "abc"]
        rail_a = stepper.LookupRail(
            stepper_configs[0], need_position_minmax=False, units_in_radians=True
        )
        a_endstop = rail_a.get_homing_info().position_endstop
        rail_b = stepper.LookupRail(
            stepper_configs[1],
            need_position_minmax=False,
            default_position_endstop=a_endstop,
            units_in_radians=True,
        )
        rail_c = stepper.LookupRail(
            stepper_configs[2],
            need_position_minmax=False,
            default_position_endstop=a_endstop,
            units_in_radians=True,
        )
        self.rails = [rail_a, rail_b, rail_c]
        # Read config
        max_velocity, max_accel = toolhead.get_max_velocity()
        self.max_z_velocity = config.getfloat(
            "max_z_velocity", max_velocity, above=0.0, maxval=max_velocity
        )
        shoulder_radius = config.getfloat("shoulder_radius", above=0.0)
        shoulder_height = config.getfloat("shoulder_height", above=0.0)
        a_upper_arm = stepper_configs[0].getfloat("upper_arm_length", above=0.0)
        upper_arms = [
            sconfig.getfloat("upper_arm_length", a_upper_arm, above=0.0)
            for sconfig in stepper_configs
        ]
        a_lower_arm = stepper_configs[0].getfloat("lower_arm_length", above=0.0)
        lower_arms = [
            sconfig.getfloat("lower_arm_length", a_lower_arm, above=0.0)
            for sconfig in stepper_configs
        ]
        angles = [
            sconfig.getfloat("angle", angle)
            for sconfig, angle in zip(stepper_configs, [30.0, 150.0, 270.0])
        ]
        # Setup rotary delta calibration helper
        endstops = [rail.get_homing_info().position_endstop for rail in self.rails]
        stepdists = [rail.get_steppers()[0].get_step_dist() for rail in self.rails]
        self.calibration = RotaryDeltaCalibration(
            shoulder_radius,
            shoulder_height,
            angles,
            upper_arms,
            lower_arms,
            endstops,
            stepdists,
        )
        # Setup iterative solver
        for r, a, ua, la in zip(self.rails, angles, upper_arms, lower_arms):
            r.setup_itersolve(
                "rotary_delta_stepper_alloc",
                shoulder_radius,
                shoulder_height,
                math.radians(a),
                ua,
                la,
            )
        for s in self.get_steppers():
            s.set_trapq(toolhead.get_trapq())
            toolhead.register_step_generator(s.generate_steps)
        # Setup boundary checks
        self.need_home = True
        self.limit_xy2 = -1.0
        eangles = [
            r.calc_position_from_coord([0.0, 0.0, ep])
            for r, ep in zip(self.rails, endstops)
        ]
        self.home_position = tuple(self.calibration.actuator_to_cartesian(eangles))
        self.max_z = min(endstops)
        self.min_z = config.getfloat("minimum_z_position", 0, maxval=self.max_z)
        min_ua = min([shoulder_radius + ua for ua in upper_arms])
        min_la = min([la - shoulder_radius for la in lower_arms])
        self.max_xy2 = min(min_ua, min_la) ** 2
        arm_z = [self.calibration.elbow_coord(i, ea)[2] for i, ea in enumerate(eangles)]
        self.limit_z = min([az - la for az, la in zip(arm_z, lower_arms)])
        logging.info(
            "Delta max build height %.2fmm (radius tapered above %.2fmm)"
            % (self.max_z, self.limit_z)
        )
        max_xy = math.sqrt(self.max_xy2)
        self.axes_min = toolhead.Coord(-max_xy, -max_xy, self.min_z, 0.0)
        self.axes_max = toolhead.Coord(max_xy, max_xy, self.max_z, 0.0)
        self.set_position([0.0, 0.0, 0.0], "")

    def get_steppers(self):
        return [s for rail in self.rails for s in rail.get_steppers()]

    def calc_position(self, stepper_positions):
        spos = [stepper_positions[rail.get_name()] for rail in self.rails]
        return self.calibration.actuator_to_cartesian(spos)

    def set_position(self, newpos, homing_axes):
        for rail in self.rails:
            rail.set_position(newpos)
        self.limit_xy2 = -1.0
        if homing_axes == "xyz":
            self.need_home = False

    def clear_homing_state(self, clear_axes):
        # Clearing homing state for each axis individually is not implemented
        if clear_axes:
            self.limit_xy2 = -1
            self.need_home = True

    def home(self, homing_state):
        # All axes are homed simultaneously
        homing_state.set_axes([0, 1, 2])
        forcepos = list(self.home_position)
        # min_angles = [-.5 * math.pi] * 3
        # forcepos[2] = self.calibration.actuator_to_cartesian(min_angles)[2]
        forcepos[2] = -1.0
        homing_state.home_rails(self.rails, forcepos, self.home_position)

    def check_move(self, move):
        end_pos = move.end_pos
        end_xy2 = end_pos[0] ** 2 + end_pos[1] ** 2
        if end_xy2 <= self.limit_xy2 and not move.axes_d[2]:
            # Normal XY move
            return
        if self.need_home:
            raise move.move_error("Must home first")
        end_z = end_pos[2]
        limit_xy2 = self.max_xy2
        if end_z > self.limit_z:
            limit_xy2 = min(limit_xy2, (self.max_z - end_z) ** 2)
        if end_xy2 > limit_xy2 or end_z > self.max_z or end_z < self.min_z:
            # Move out of range - verify not a homing move
            if (
                end_pos[:2] != self.home_position[:2]
                or end_z < self.min_z
                or end_z > self.home_position[2]
            ):
                raise move.move_error()
            limit_xy2 = -1.0
        if move.axes_d[2]:
            move.limit_speed(self.max_z_velocity, move.accel)
            limit_xy2 = -1.0
        self.limit_xy2 = limit_xy2

    def get_status(self, eventtime):
        return {
            "homed_axes": "" if self.need_home else "xyz",
            "axis_minimum": self.axes_min,
            "axis_maximum": self.axes_max,
        }

    def get_calibration(self):
        return self.calibration


# Rotary delta parameter calibration for DELTA_CALIBRATE tool
class RotaryDeltaCalibration:
    def __init__(
        self,
        shoulder_radius,
        shoulder_height,
        angles,
        upper_arms,
        lower_arms,
        endstops,
        stepdists,
    ):
        self.shoulder_radius = shoulder_radius
        self.shoulder_height = shoulder_height
        self.angles = angles
        self.upper_arms = upper_arms
        self.lower_arms = lower_arms
        self.endstops = endstops
        self.stepdists = stepdists
        # Calculate the absolute angle of each endstop
        ffi_main, self.ffi_lib = chelper.get_ffi()
        self.sks = [
            ffi_main.gc(
                self.ffi_lib.rotary_delta_stepper_alloc(
                    shoulder_radius, shoulder_height, math.radians(a), ua, la
                ),
                self.ffi_lib.free,
            )
            for a, ua, la in zip(angles, upper_arms, lower_arms)
        ]
        self.abs_endstops = [
            self.ffi_lib.itersolve_calc_position_from_coord(sk, 0.0, 0.0, es)
            for sk, es in zip(self.sks, endstops)
        ]

    def coordinate_descent_params(self, is_extended):
        # Determine adjustment parameters (for use with coordinate_descent)
        adj_params = ("shoulder_height", "endstop_a", "endstop_b", "endstop_c")
        if is_extended:
            adj_params += ("shoulder_radius", "angle_a", "angle_b")
        params = {
            "shoulder_radius": self.shoulder_radius,
            "shoulder_height": self.shoulder_height,
        }
        for i, axis in enumerate("abc"):
            params["angle_" + axis] = self.angles[i]
            params["upper_arm_" + axis] = self.upper_arms[i]
            params["lower_arm_" + axis] = self.lower_arms[i]
            params["endstop_" + axis] = self.endstops[i]
            params["stepdist_" + axis] = self.stepdists[i]
        return adj_params, params

    def new_calibration(self, params):
        # Create a new calibration object from coordinate_descent params
        shoulder_radius = params["shoulder_radius"]
        shoulder_height = params["shoulder_height"]
        angles = [params["angle_" + a] for a in "abc"]
        upper_arms = [params["upper_arm_" + a] for a in "abc"]
        lower_arms = [params["lower_arm_" + a] for a in "abc"]
        endstops = [params["endstop_" + a] for a in "abc"]
        stepdists = [params["stepdist_" + a] for a in "abc"]
        return RotaryDeltaCalibration(
            shoulder_radius,
            shoulder_height,
            angles,
            upper_arms,
            lower_arms,
            endstops,
            stepdists,
        )

    def elbow_coord(self, elbow_id, spos):
        # Calculate elbow position in coordinate system at shoulder joint
        sj_elbow_x = self.upper_arms[elbow_id] * math.cos(spos)
        sj_elbow_y = self.upper_arms[elbow_id] * math.sin(spos)
        # Shift and rotate to main cartesian coordinate system
        angle = math.radians(self.angles[elbow_id])
        x = (sj_elbow_x + self.shoulder_radius) * math.cos(angle)
        y = (sj_elbow_x + self.shoulder_radius) * math.sin(angle)
        z = sj_elbow_y + self.shoulder_height
        return (x, y, z)

    def actuator_to_cartesian(self, spos):
        sphere_coords = [self.elbow_coord(i, sp) for i, sp in enumerate(spos)]
        lower_arm2 = [la**2 for la in self.lower_arms]
        return mathutil.trilateration(sphere_coords, lower_arm2)

    def get_position_from_stable(self, stable_position):
        # Return cartesian coordinates for the given stable_position
        spos = [
            ea - sp * sd
            for ea, sp, sd in zip(self.abs_endstops, stable_position, self.stepdists)
        ]
        return self.actuator_to_cartesian(spos)

    def calc_stable_position(self, coord):
        # Return a stable_position from a cartesian coordinate
        pos = [
            self.ffi_lib.itersolve_calc_position_from_coord(
                sk, coord[0], coord[1], coord[2]
            )
            for sk in self.sks
        ]
        return [
            (ep - sp) / sd for sd, ep, sp in zip(self.stepdists, self.abs_endstops, pos)
        ]

    def save_state(self, configfile):
        # Save the current parameters (for use with SAVE_CONFIG)
        configfile.set("printer", "shoulder_radius", "%.6f" % (self.shoulder_radius,))
        configfile.set("printer", "shoulder_height", "%.6f" % (self.shoulder_height,))
        for i, axis in enumerate("abc"):
            configfile.set("stepper_" + axis, "angle", "%.6f" % (self.angles[i],))
            configfile.set(
                "stepper_" + axis, "position_endstop", "%.6f" % (self.endstops[i],)
            )
        gcode = configfile.get_printer().lookup_object("gcode")
        gcode.respond_info(
            "stepper_a: position_endstop: %.6f angle: %.6f\n"
            "stepper_b: position_endstop: %.6f angle: %.6f\n"
            "stepper_c: position_endstop: %.6f angle: %.6f\n"
            "shoulder_radius: %.6f shoulder_height: %.6f"
            % (
                self.endstops[0],
                self.angles[0],
                self.endstops[1],
                self.angles[1],
                self.endstops[2],
                self.angles[2],
                self.shoulder_radius,
                self.shoulder_height,
            )
        )


def load_kinematics(toolhead, config):
    return RotaryDeltaKinematics(toolhead, config)