Files
TIR_PROJ/herding/control/active_scan.py
Johnny Fernandes 7ab69ab0f3 Rename multi-segment functions to two-concept names; polish docstrings
Naming pass: rename functions whose third+ segment is redundant or
implementation-detail, sticking to the codebase's preferred
``noun_verb`` / ``verb_noun`` two-concept idiom. Renames are atomic
across definitions, callers, and tests.

  is_penned_position        →  is_penned
  modulate_speed_near_sheep →  modulate_speed
  mecanum_kinematics_step   →  mecanum_step
  policy_forward_mean       →  forward_mean

Two-concept patterns like ``velocity_to_wheels`` / ``detections_from_scan``
/ ``make_strombom_predictor`` are left alone — they're idiomatic
converters / factories that read as a single concept, and the longer
form aids grep-ability.

Docstring polish:
* ``herding/config.py`` header drops the "previously lived as a
  module-level literal" historical framing — we ship as a single
  thing, so the refactor anecdote no longer earns its keep. The
  usage examples now mention both ``HERDING_WEBOTS`` and
  ``HERDING_MEC_WEBOTS`` presets.

126 pytest cases still pass.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-17 01:58:15 +00:00

123 lines
4.4 KiB
Python

"""Active-perception wrapper for the analytic shepherd teachers.
Under partial-observability LiDAR perception the tracker starts empty
— a naive analytic teacher returns ``(0, 0, "idle")`` and the dog
stops. This wrapper interleaves the underlying teacher with two
exploration behaviours:
* opening in-place rotation for the first ``INITIAL_SCAN_STEPS``,
guaranteeing the LiDAR sweeps a full circle before driving;
* walk-to-centre when the tracker has been empty for at least
``EMPTY_DEBOUNCE_STEPS`` consecutive frames (corners can sit
beyond the 12 m LiDAR range).
When the tracker has detections the base teacher's action is used,
post-processed by ``modulate_speed`` so the dog doesn't
charge the flock.
"""
from __future__ import annotations
import math
from herding.control.modulation import modulate_speed
INITIAL_SCAN_STEPS = 80 # ≈1.3 s — covers one full rotation
EXPLORE_SPEED = 0.7 # action norm while walking blind
EMPTY_DEBOUNCE_STEPS = 8 # consecutive empty frames before exploring
class ActiveScanTeacher:
"""Stateful wrapper. Construct one per episode (or call ``reset``).
Call signature::
vx, vy, omega, mode = teacher(dog_xy, dog_heading, sheep_positions,
pen_target, drive_mode="differential")
``omega`` is the yaw-rate intent (mecanum only); 0.0 for differential
drive and during blind exploration phases.
"""
def __init__(self, base_action_fn, initial_scan_steps: int = INITIAL_SCAN_STEPS):
self.base = base_action_fn
self.initial_scan = int(initial_scan_steps)
self.reset()
def reset(self) -> None:
self.step = 0
self.empty_streak = 0
self.last_action: tuple[float, float] = (0.0, 0.0)
@staticmethod
def _scan_action(dog_heading: float) -> tuple[float, float]:
# Target opposite to current heading; velocity_to_wheels'
# cos(err) clamp drives forward speed to ~0 → in-place rotation.
target = dog_heading + math.pi
return math.cos(target), math.sin(target)
@staticmethod
def _explore_action(dog_xy) -> tuple[float, float]:
"""Walk toward (0, 0) while the LiDAR keeps sweeping."""
dx, dy = -dog_xy[0], -dog_xy[1]
d = math.hypot(dx, dy)
if d < 0.5:
return 0.0, 0.0
return EXPLORE_SPEED * dx / d, EXPLORE_SPEED * dy / d
def __call__(self, dog_xy, dog_heading, sheep_positions, pen_target,
drive_mode="differential"):
self.step += 1
n_visible = len(sheep_positions)
if n_visible == 0:
self.empty_streak += 1
else:
self.empty_streak = 0
# Phase 1: opening rotation.
if self.step <= self.initial_scan:
vx, vy = self._scan_action(dog_heading)
self.last_action = (vx, vy)
return vx, vy, 0.0, "scan_initial"
# Phase 2: walk-to-centre after a sustained empty tracker.
if self.empty_streak >= EMPTY_DEBOUNCE_STEPS:
ex, ey = self._explore_action(dog_xy)
if ex == 0.0 and ey == 0.0:
vx, vy = self._scan_action(dog_heading)
mode = "scan_at_centre"
else:
vx, vy = ex, ey
mode = "explore"
self.last_action = (vx, vy)
return vx, vy, 0.0, mode
# Phase 2b: brief tracker blink — hold the previous action.
if n_visible == 0:
vx, vy = self.last_action
return vx, vy, 0.0, "hold"
# Phase 3: hand off to the underlying analytic teacher, then
# apply the shared near-sheep speed modulation.
# Handle both old-style (dog_xy, sheep, pen) and new-style
# (dog_xy, heading, sheep, pen, drive_mode) teachers.
try:
result = self.base(dog_xy, dog_heading, sheep_positions,
pen_target, drive_mode)
except TypeError:
try:
result = self.base(dog_xy, dog_heading, sheep_positions,
pen_target)
except TypeError:
result = self.base(dog_xy, sheep_positions, pen_target)
if len(result) == 4:
vx, vy, omega, mode = result
else:
vx, vy, mode = result
omega = 0.0
vx, vy = modulate_speed(vx, vy, dog_xy, sheep_positions)
self.last_action = (vx, vy)
return vx, vy, omega, mode