source/bimanual/yam/tasks/bell_coaster.py

"""Slide the desk bell onto its coaster, without grasping it.

RoboTwin has "Click Bell"; this is deliberately not that. The bell here is a plain rigid mesh
with no plunger joint, so a "press" cannot register anything -- a rigid body on a rigid table
does not move under a downward push, and the check would be measuring nothing (it read 0.0 mm).
What IS measurable is sliding it: the bell is dome-shaped and top-heavy, so it tips easily, and
the task is to get it onto the coaster while leaving it standing.
"""
from ..registry import register_task
from ..envs import YamTaskEnv
from ..solvers import push
from .. import conditions as C


@register_task("bell_coaster")
class BellCoasterTask(YamTaskEnv):
    title = "SLIDE THE BELL ONTO ITS COASTER"
    tags = ["push", "no-grasp", "contact-rich", "robotwin-asset"]
    instruction = {"default": "Push the bell onto the coaster."}

    # 0.075 made a 14 cm desk bell; this is a believable 8.5 cm one. Mass 0.40 kg because a
    # desk bell IS heavy metal, and at 0.12 kg the dome tipped instead of sliding.
    rw_objects = {"rw_bell": "050_bell/base0.usd:0.045:0.40"}
    # Pushing toward -y means standing on the bell's +y side, and that stance sat 0.43 m from
    # the right shoulder -- out of reach, so nothing moved. The arm can only push AWAY from its
    # own shoulder at (-0.2,-0.2), so the route runs +x/+y instead.
    bell_spawn = (-0.02, -0.02)
    spawn_jitter = (0.018, 0.015)
    coaster_xy = (0.10, 0.02)
    coaster_size = 0.12

    def _load_scene(self):
        self.scene.build_marker({"name": "coaster", "xy": self.coaster_xy,
                                 "size": self.coaster_size, "color": (0.30, 0.26, 0.22),
                                 "xy_jitter": (0.015, 0.015)})
        self._placed = [self.scene.place_object(
            {"name": "rw_bell", "xy": self.bell_spawn, "xy_jitter": self.spawn_jitter})]

    def solve(self):
        e = self.scene.object_size("rw_bell")
        print(f"[task] bell {e.round(3)} m", flush=True)
        # a dome tips if shoved high up, so push low and slowly
        # push LOW on the dome: at 45% of its height it tipped over and rolled 15 cm past
        return push.solve(self, obj="rw_bell", target="coaster", advance=0.005,
                          steps=300, push_z_frac=0.10,
                          stop_dist=self.coaster_size*0.5)

    # NOT YET PASSING, and the remaining cause is the object, not the parameters. Three changes
    # each helped and none fixed it:
    #   push_z_frac 0.45 -> 0.18 -> 0.10 (contact at the skirt)   overshoot 0.154 -> 0.079 m
    #   stop the push early and let it coast in                    overshoot -> 0.055 m
    #   mass 0.12 -> 0.40 kg (a desk bell is heavy metal)          overshoot 0.059 m
    # Position is now inside tolerance, but "still standing" keeps failing: a DOME rotates under
    # any horizontal contact, so it rolls rather than slides. The honest options are to push it
    # with a flat tool (a swept plate rather than a fingertip), or to replace the bell with an
    # object that has a flat side. Do not simply relax object_level to make it pass.
    def evaluate(self):
        return self.check(
            C.labelled("bell on the coaster", C.object_moved_to("rw_bell", "coaster", tol=0.06)),
            C.labelled("bell still standing", C.object_level("rw_bell", 25.0)))