wall_clean: default arc_omega 0.1, drive the first leg straight

Two cleaning tweaks:

- Bump the default cruise arc rate from 0.05 to 0.1 rad/s (launch built-in
  default and the node's declared default, kept in sync).

- Skip the arc on the very first cruise leg. The workflow is to aim the
  robot at the target wall with teleop and then launch wall_clean; arcing
  during that approach forces you to pre-aim off-axis to compensate.
  A new _first_leg flag makes the initial approach dead straight and clears
  on the first bump, so the wall-hugging arc engages only once we're
  actually following a wall.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: kaiaai

src/oomwoo_clean/launch/wall_clean.launch.py

@@ -33,7 +33,7 @@
 # name -> built-in default; each is overridable by kaia (clean.<name>) then :=
 CLEAN_PARAMS = {
     'v_cruise': 0.15,       # forward cleaning speed (m/s)
-    'arc_omega': 0.05,       # gentle right-arc rate while cruising (rad/s)
+    'arc_omega': 0.1,        # gentle right-arc rate while cruising (rad/s)
     'v_back': 0.10,         # backoff reverse speed (m/s)
     'backoff_s': 0.5,       # backoff duration (s)
     'turn_speed': 0.7,      # angular speed while turning left (rad/s)

src/oomwoo_clean/oomwoo_clean/wall_clean_node.py

@@ -74,7 +74,7 @@ class WallClean(Node):
     def __init__(self) -> None:
         super().__init__('wall_clean')
         self.v_cruise = self.declare_parameter('v_cruise', 0.15).value
-        self.arc_omega = self.declare_parameter('arc_omega', 0.05).value
+        self.arc_omega = self.declare_parameter('arc_omega', 0.1).value
         self.v_back = self.declare_parameter('v_back', 0.10).value
         self.backoff_s = self.declare_parameter('backoff_s', 0.5).value
         self.turn_speed = self.declare_parameter('turn_speed', 0.7).value
@@ -98,6 +98,10 @@ def __init__(self) -> None:
         self._bump_left_t = None
         self._bump_right_t = None
         self._side = 'both'
+        # First leg: I aim the robot at the wall with teleop and launch this, so
+        # the approach should be a STRAIGHT line (no arc to compensate for). The
+        # arc kicks in only after the first bump, once we're following the wall.
+        self._first_leg = True
         self.state = CRUISE
         self.until = self.get_clock().now()
         self.create_timer(1.0 / hz, self._tick)
@@ -149,11 +153,14 @@ def _drive(self, lin, ang) -> None:
     def _tick(self) -> None:
         now = self.get_clock().now()
         if self.state == CRUISE:
-            # forward + gentle RIGHT arc, drifting toward the wall on the right
-            self._drive(self.v_cruise, -self.arc_omega)
+            # forward + gentle RIGHT arc, drifting toward the wall on the right;
+            # the very first leg (teleop-aimed approach) drives dead straight
+            arc = 0.0 if self._first_leg else -self.arc_omega
+            self._drive(self.v_cruise, arc)
             left = self._pressed(self._bump_left_t, now)
             right = self._pressed(self._bump_right_t, now)
             if left or right:
+                self._first_leg = False   # from here on, arc toward the wall
                 self._side = 'both' if left and right else (
                     'left' if left else 'right')
                 self.state = BACKOFF