Make SCC Vision curve pacing smooth and bounded

Use model curvature to lower cruise speed smoothly while bounding slowdown, preserving launch response, and avoiding acceleration and braking oscillation.

sunnypilot/selfdrive/controls/lib/smart_cruise_control/tests/test_vision_controller.py

@@ -4,6 +4,8 @@ Copyright (c) 2021-, Haibin Wen, sunnypilot, and a number of other contributors.
 This file is part of sunnypilot and is licensed under the MIT License.
 See the LICENSE.md file in the root directory for more details.
 """
+from types import SimpleNamespace
+
 import numpy as np
 import pytest
 
@@ -13,8 +15,12 @@ from openpilot.common.params import Params
 from openpilot.common.realtime import DT_MDL
 from openpilot.selfdrive.car.cruise import V_CRUISE_UNSET
 from openpilot.selfdrive.modeld.constants import ModelConstants
+from openpilot.sunnypilot.selfdrive.controls.lib.longitudinal_planner import LongitudinalPlannerSP, LongitudinalPlanSource
 from openpilot.sunnypilot.selfdrive.controls.lib.smart_cruise_control import MIN_V
-from openpilot.sunnypilot.selfdrive.controls.lib.smart_cruise_control.vision_controller import SmartCruiseControlVision, _ENTERING_PRED_LAT_ACC_TH
+from openpilot.sunnypilot.selfdrive.controls.lib.smart_cruise_control.vision_controller import (
+  _A_LAT_REG_MAX, _BELOW_EGO_TARGET_RELEASE_RATE, _ENTERING_PRED_LAT_ACC_TH, _MIN_ACTIVATION_SPEED,
+  _RELIEF_CONFIRMATION_FRAMES, _TARGET_RELEASE_RATE, SmartCruiseControlVision,
+)
 
 VisionState = custom.LongitudinalPlanSP.SmartCruiseControl.VisionState
 
@@ -118,6 +124,21 @@ class TestSmartCruiseControlVision:
   def reset_params(self):
     self.params.put_bool("SmartCruiseControlVision", True, block=True)
 
+  def set_lat_accels(self, current: float, predicted: float, v_ego: float = 20., model_speed: float = 20.) -> None:
+    self.sm['controlsState'].curvature = current / v_ego**2
+    self.sm['modelV2'].velocity.x = [model_speed] * len(ModelConstants.T_IDXS)
+    self.sm['modelV2'].orientationRate.z = [predicted / model_speed] * len(ModelConstants.T_IDXS)
+
+  def update_lat_accels(self, current: float, predicted: float, cruise: float = 30., a_ego: float = 0.,
+                        v_ego: float = 20., model_speed: float = 20.) -> None:
+    self.set_lat_accels(current, predicted, v_ego, model_speed)
+    self.scc_v.update(self.sm, True, False, v_ego, a_ego, cruise)
+
+  def enter_curve(self, predicted: float = 2.2) -> None:
+    self.update_lat_accels(0.5, predicted)
+    self.update_lat_accels(0.5, predicted)
+    assert self.scc_v.state == VisionState.entering
+
   def test_initial_state(self):
     assert self.scc_v.state == VisionState.disabled
     assert not self.scc_v.is_active
@@ -143,6 +164,253 @@ class TestSmartCruiseControlVision:
       self.scc_v.update(self.sm, True, False, 0., 0., 0.)
     assert self.scc_v.state == VisionState.enabled
 
+  def test_unconfirmed_leaving_and_reentry_only_shape_speed(self):
+    self.enter_curve()
+    targets = [self.scc_v.output_v_target]
+
+    self.update_lat_accels(2., 2.2, a_ego=-0.8)
+    assert self.scc_v.state == VisionState.turning
+    assert self.scc_v.output_a_target == -0.8
+    targets.append(self.scc_v.output_v_target)
+
+    self.update_lat_accels(1.2, 1.2, a_ego=0.3)
+    assert self.scc_v.state == VisionState.leaving
+    assert self.scc_v.output_a_target == 0.3
+    targets.append(self.scc_v.output_v_target)
+
+    self.update_lat_accels(1., 3., a_ego=-1.2)
+    assert self.scc_v.state == VisionState.entering
+    assert self.scc_v.output_a_target == -1.2
+    targets.append(self.scc_v.output_v_target)
+
+    entering, turning, leaving, reentering = targets
+    assert turning == pytest.approx(entering)
+    assert 0. < leaving - turning <= _BELOW_EGO_TARGET_RELEASE_RATE * DT_MDL + 1e-9
+    assert reentering < leaving
+
+  def test_new_curve_interrupts_confirmed_release_immediately(self):
+    self.enter_curve()
+    for _ in range(_RELIEF_CONFIRMATION_FRAMES + 1):
+      self.update_lat_accels(0.8, 0.8)
+    releasing_v_target = self.scc_v.output_v_target
+    assert self.scc_v.state == VisionState.leaving
+
+    self.update_lat_accels(0.8, 3., a_ego=-0.7)
+    assert self.scc_v.state == VisionState.entering
+    assert self.scc_v.output_v_target < releasing_v_target
+    assert self.scc_v.output_a_target == -0.7
+
+  @pytest.mark.parametrize("planner_accel", (-2., -0.5, 0., 0.8))
+  def test_planner_acceleration_passes_through_exactly(self, planner_accel):
+    self.enter_curve()
+    self.update_lat_accels(0.5, 2.2, a_ego=planner_accel)
+    assert self.scc_v.output_a_target == planner_accel
+
+  def test_planner_acceleration_passes_through_all_states(self):
+    cases = (
+      (False, False, 0.5, 2.2, -0.2, VisionState.disabled),
+      (True, False, 0.5, 0.8, 0.1, VisionState.enabled),
+      (True, False, 0.5, 2.2, -0.4, VisionState.entering),
+      (True, False, 2., 2.2, -0.8, VisionState.turning),
+      (True, False, 1.2, 1.2, 0.3, VisionState.leaving),
+      (True, True, 1.2, 1.2, 0.6, VisionState.overriding),
+    )
+    for long_enabled, override, current, predicted, planner_accel, state in cases:
+      self.set_lat_accels(current, predicted)
+      self.scc_v.update(self.sm, long_enabled, override, 20., planner_accel, 30.)
+      assert self.scc_v.state == state
+      assert self.scc_v.output_a_target == planner_accel
+
+  def test_jitter_requires_confirmed_relief_then_releases_smoothly(self):
+    self.enter_curve()
+    previous_v_target = self.scc_v.output_v_target
+
+    for frame in range(_RELIEF_CONFIRMATION_FRAMES * 2):
+      self.update_lat_accels(1., 1.05 if frame % 2 == 0 else 1.15)
+      assert self.scc_v.state == VisionState.entering
+      assert self.scc_v.output_v_target >= previous_v_target
+      assert self.scc_v.output_v_target - previous_v_target <= _BELOW_EGO_TARGET_RELEASE_RATE * DT_MDL + 1e-9
+      previous_v_target = self.scc_v.output_v_target
+
+    for _ in range(_RELIEF_CONFIRMATION_FRAMES):
+      self.update_lat_accels(1.15, 0.8)
+      assert self.scc_v.state == VisionState.entering
+      assert 0. <= self.scc_v.output_v_target - previous_v_target <= _BELOW_EGO_TARGET_RELEASE_RATE * DT_MDL + 1e-9
+      previous_v_target = self.scc_v.output_v_target
+
+    release_cruise = 30.
+    for _ in range(_RELIEF_CONFIRMATION_FRAMES - 1):
+      self.update_lat_accels(0.8, 0.8, release_cruise)
+      assert self.scc_v.state == VisionState.entering
+      assert 0. <= self.scc_v.output_v_target - previous_v_target <= _BELOW_EGO_TARGET_RELEASE_RATE * DT_MDL + 1e-9
+      previous_v_target = self.scc_v.output_v_target
+
+    active_v_targets = [previous_v_target]
+    for _ in range(int((release_cruise - previous_v_target) / (_TARGET_RELEASE_RATE * DT_MDL)) + 10):
+      self.update_lat_accels(0.8, 0.8, release_cruise)
+      if not self.scc_v.is_active:
+        break
+      assert self.scc_v.state == VisionState.leaving
+      assert self.scc_v.output_v_target != V_CRUISE_UNSET
+      active_v_targets.append(self.scc_v.output_v_target)
+
+    assert self.scc_v.state == VisionState.enabled
+    assert self.scc_v.output_v_target == V_CRUISE_UNSET
+    assert active_v_targets[-1] == pytest.approx(release_cruise)
+    assert np.all((np.diff(active_v_targets) >= 0.) &
+                  (np.diff(active_v_targets) <= _BELOW_EGO_TARGET_RELEASE_RATE * DT_MDL + 1e-9))
+
+  def test_target_release_slows_after_reaching_ego_speed(self):
+    self.enter_curve()
+
+    for _ in range(100):
+      previous_v_target = self.scc_v.output_v_target
+      self.update_lat_accels(0.8, 0.8)
+      if previous_v_target >= self.scc_v.v_ego:
+        rise = self.scc_v.output_v_target - previous_v_target
+        assert 0. < rise <= _TARGET_RELEASE_RATE * DT_MDL + 1e-9
+        break
+    else:
+      pytest.fail("curve target did not release to ego speed")
+
+  def test_curve_target_is_independent_of_ego_speed(self):
+    model_speed = 24.
+    predicted_yaw_rate = 0.12
+    predicted_lat_accel = model_speed * predicted_yaw_rate
+    expected_v_target = (_A_LAT_REG_MAX / (predicted_yaw_rate / model_speed)) ** 0.5
+    targets = []
+
+    for v_ego in (18., 28.):
+      controller = SmartCruiseControlVision()
+      self.set_lat_accels(0.5, predicted_lat_accel, v_ego, model_speed)
+      controller.update(self.sm, True, False, v_ego, 0., 30.)
+      controller.update(self.sm, True, False, v_ego, 0., 30.)
+      assert controller.state == VisionState.entering
+      targets.append(controller.v_target)
+
+    assert targets[0] == pytest.approx(expected_v_target)
+    assert targets[1] == pytest.approx(expected_v_target)
+
+  def test_curve_target_respects_minimum_speed_floor(self):
+    model_speed = 10.
+    predicted_yaw_rate = 2.
+    self.set_lat_accels(0.5, model_speed * predicted_yaw_rate, model_speed=model_speed)
+    self.scc_v.update(self.sm, True, False, 20., 0., 30.)
+    self.scc_v.update(self.sm, True, False, 20., 0., 30.)
+
+    assert self.scc_v.state == VisionState.entering
+    assert self.scc_v.v_target < MIN_V
+    assert self.scc_v.output_v_target == pytest.approx(MIN_V)
+
+  @pytest.mark.parametrize(
+    ("velocities", "yaw_rates"),
+    [([], []), ([np.nan] * len(ModelConstants.T_IDXS), [np.nan] * len(ModelConstants.T_IDXS)), ([20.] * 5, [0.1] * 3)],
+    ids=("empty", "nonfinite", "mismatched"),
+  )
+  def test_model_vector_edges_remain_finite(self, velocities, yaw_rates):
+    self.sm['modelV2'].velocity.x = velocities
+    self.sm['modelV2'].orientationRate.z = yaw_rates
+    self.scc_v.update(self.sm, True, False, 20., 0., 30.)
+    self.scc_v.update(self.sm, True, False, 20., 0., 30.)
+
+    assert all(np.isfinite(value) for value in (
+      self.scc_v.current_lat_acc, self.scc_v.max_pred_lat_acc, self.scc_v.v_target,
+      self.scc_v.output_v_target, self.scc_v.output_a_target,
+    ))
+
+  @pytest.mark.parametrize("launch_speed", (5.75, 9.9, _MIN_ACTIVATION_SPEED))
+  def test_vision_control_does_not_steal_launch(self, launch_speed):
+    self.set_lat_accels(0.5, 3., launch_speed)
+    self.scc_v.update(self.sm, True, False, launch_speed, 0., 30.)
+    self.scc_v.update(self.sm, True, False, launch_speed, 0., 30.)
+
+    assert launch_speed <= _MIN_ACTIVATION_SPEED
+    assert self.scc_v.state == VisionState.enabled
+    assert not self.scc_v.is_active
+    assert self.scc_v.output_v_target == V_CRUISE_UNSET
+
+  def test_vision_control_can_activate_above_launch_range(self):
+    speed = _MIN_ACTIVATION_SPEED + 0.01
+    self.set_lat_accels(0.5, 3., speed)
+    self.scc_v.update(self.sm, True, False, speed, 0., 30.)
+    self.scc_v.update(self.sm, True, False, speed, 0., 30.)
+
+    assert self.scc_v.state == VisionState.entering
+    assert self.scc_v.is_active
+
+  def test_sequential_curve_tightens_immediately_and_releases_bounded(self):
+    self.enter_curve(3.)
+    for _ in range(20):
+      self.update_lat_accels(0.5, 3.)
+    restrictive_v_target = self.scc_v.output_v_target
+
+    self.update_lat_accels(0.5, 1.4, a_ego=0.4)
+    first_relief_v_target = self.scc_v.output_v_target
+    assert self.scc_v.state == VisionState.entering
+    assert 0. < first_relief_v_target - restrictive_v_target <= _BELOW_EGO_TARGET_RELEASE_RATE * DT_MDL + 1e-9
+    assert self.scc_v.output_a_target == 0.4
+
+    self.update_lat_accels(0.5, 1.4)
+    assert 0. <= self.scc_v.output_v_target - first_relief_v_target <= _BELOW_EGO_TARGET_RELEASE_RATE * DT_MDL + 1e-9
+
+    self.update_lat_accels(0.5, 3., a_ego=-0.6)
+    assert self.scc_v.state == VisionState.entering
+    assert self.scc_v.output_v_target == pytest.approx(restrictive_v_target)
+    assert self.scc_v.output_a_target == -0.6
+
+    for _ in range(4):
+      self.update_lat_accels(0.5, 1.4)
+      assert 0. < self.scc_v.output_v_target - restrictive_v_target <= _BELOW_EGO_TARGET_RELEASE_RATE * DT_MDL + 1e-9
+      self.update_lat_accels(0.5, 3.)
+      assert self.scc_v.output_v_target == pytest.approx(restrictive_v_target)
+
+  def test_acceleration_is_continuous_through_planner_arbitration(self):
+    car_control = messaging.new_message('carControl')
+    car_control.carControl.enabled = True
+    car_control.carControl.cruiseControl.override = False
+    self.sm['carControl'] = car_control.carControl
+    self.sm['carState'].vCruiseCluster = 108.
+
+    planner = LongitudinalPlannerSP.__new__(LongitudinalPlannerSP)
+    planner.scc = SimpleNamespace(
+      vision=self.scc_v,
+      map=SimpleNamespace(output_v_target=V_CRUISE_UNSET, output_a_target=0.),
+      update=lambda sm, enabled, override, v_ego, a_ego, v_cruise: self.scc_v.update(
+        sm, enabled, override, v_ego, a_ego, v_cruise),
+    )
+    planner.resolver = SimpleNamespace(
+      speed_limit_valid=False, speed_limit_last_valid=False, speed_limit=0., speed_limit_final_last=0., distance=0.,
+      update=lambda _v_ego, _sm: None,
+    )
+    planner.sla = SimpleNamespace(
+      output_v_target=V_CRUISE_UNSET, output_a_target=0., update=lambda *_args: None,
+    )
+    planner.events_sp = SimpleNamespace()
+
+    self.set_lat_accels(0.5, 2.2)
+    planner.update_targets(self.sm, 20., -0.8, 30.)
+    planner.update_targets(self.sm, 20., -0.8, 30.)
+    assert planner.source == LongitudinalPlanSource.sccVision
+    assert planner.output_a_target == -0.8
+
+    for planner_accel in (-2., 0.5, -0.2):
+      planner.update_targets(self.sm, 20., planner_accel, 30.)
+      assert planner.source == LongitudinalPlanSource.sccVision
+      assert planner.output_a_target == planner_accel
+
+    self.set_lat_accels(0.8, 0.8)
+    for _ in range(int(30. / (_TARGET_RELEASE_RATE * DT_MDL)) + 10):
+      planner.update_targets(self.sm, 20., 0.4, 30.)
+      assert planner.output_a_target == 0.4
+      if planner.source == LongitudinalPlanSource.cruise:
+        break
+    else:
+      pytest.fail("SCC Vision did not release to cruise")
+
+    planner.update_targets(self.sm, 20., 0.4, 30.)
+    assert self.scc_v.state == VisionState.enabled
+    assert planner.source == LongitudinalPlanSource.cruise
+
   @pytest.mark.parametrize(
     "case, should_enter",
     [

sunnypilot/selfdrive/controls/lib/smart_cruise_control/tests/test_vision_controller_closed_loop.py

@@ -0,0 +1,82 @@
+"""
+Copyright (c) 2021-, Haibin Wen, sunnypilot, and a number of other contributors.
+
+This file is part of sunnypilot and is licensed under the MIT License.
+See the LICENSE.md file in the root directory for more details.
+"""
+import gc
+
+import numpy as np
+
+from openpilot.selfdrive.test.longitudinal_maneuvers.plant import Plant
+from openpilot.sunnypilot.selfdrive.controls.lib.longitudinal_planner import LongitudinalPlanSource
+from openpilot.sunnypilot.selfdrive.controls.lib.smart_cruise_control.vision_controller import _A_LAT_REG_MAX
+
+
+def _run_constant_curve(*, scc_enabled: bool, cruise: float, duration: float = 70.) -> dict[str, np.ndarray]:
+  gc.collect()
+  curvature = 0.005
+  plant = Plant(lead_relevancy=False, speed=30., actuator_delay=0.15, actuator_lag=0.20)
+  planner = plant.planner
+  planner.accel_controller.enabled = False
+  planner.accel_controller.update_params = lambda: None
+  planner.dec._enabled = False
+  planner.dec._read_params = lambda: None
+  planner.scc.map.enabled = False
+  planner.scc.map.update_params = lambda: None
+  planner.scc.vision.enabled = scc_enabled
+  planner.scc.vision._update_params = lambda: None
+
+  if scc_enabled:
+    original_update_calculations = planner.scc.vision._update_calculations
+
+    def inject_constant_curvature(sm):
+      velocities = np.asarray(sm['modelV2'].velocity.x, dtype=float)
+      sm['modelV2'].orientationRate.z = (curvature * velocities).tolist()
+      sm['controlsState'].curvature = curvature
+      original_update_calculations(sm)
+
+    planner.scc.vision._update_calculations = inject_constant_curvature
+
+  original_update = planner.update
+
+  def enable_longitudinal(sm):
+    sm['carControl'].enabled = True
+    sm['carControl'].longActive = True
+    original_update(sm)
+
+  planner.update = enable_longitudinal
+  rows = []
+  while plant.current_time < duration:
+    output = plant.step(v_cruise=cruise)
+    rows.append((
+      plant.current_time, output['speed'], planner.mpc.last_solution_status, output['should_stop'],
+      planner.scc.vision.is_active, planner.source == LongitudinalPlanSource.sccVision,
+      planner.scc.vision.output_v_target,
+    ))
+
+  data = np.asarray(rows, dtype=float)
+  gc.collect()
+  return {
+    'time': data[:, 0], 'speed': data[:, 1], 'solver_status': data[:, 2], 'should_stop': data[:, 3],
+    'active': data[:, 4], 'scc_source': data[:, 5], 'target': data[:, 6],
+  }
+
+
+def test_constant_curve_recovers_like_stock_speed_cap():
+  target = (_A_LAT_REG_MAX / 0.005) ** 0.5
+  scc = _run_constant_curve(scc_enabled=True, cruise=30.)
+  stock = _run_constant_curve(scc_enabled=False, cruise=target)
+  scc_final = scc['speed'][scc['time'] >= 60.]
+  stock_final = stock['speed'][stock['time'] >= 60.]
+
+  assert not scc['solver_status'].any()
+  assert not stock['solver_status'].any()
+  assert not scc['should_stop'].any()
+  assert np.all(scc['active'][scc['time'] >= 60.])
+  assert np.all(scc['scc_source'][scc['time'] >= 60.])
+  assert np.allclose(scc['target'][scc['time'] >= 60.], target)
+  assert scc_final.min() >= target - 1.
+  assert abs(scc_final.mean() - stock_final.mean()) < 0.5
+  assert abs(scc_final.min() - stock_final.min()) < 1.
+  assert abs(scc_final.max() - stock_final.max()) < 1.

sunnypilot/selfdrive/controls/lib/smart_cruise_control/vision_controller.py

@@ -29,19 +29,11 @@ _FINISH_LAT_ACC_TH = 1.1  # Lat Acc threshold to trigger the end of the turn cyc
 
 _A_LAT_REG_MAX = 2.  # Maximum lateral acceleration
 
-_NO_OVERSHOOT_TIME_HORIZON = 4.  # s. Time to use for velocity desired based on a_target when not overshooting.
-
-# Lookup table for the minimum smooth deceleration during the ENTERING state
-# depending on the actual maximum absolute lateral acceleration predicted on the turn ahead.
-_ENTERING_SMOOTH_DECEL_V = [-0.2, -1.]  # min decel value allowed on ENTERING state
-_ENTERING_SMOOTH_DECEL_BP = [1.3, 3.]  # absolute value of lat acc ahead
-
-# Lookup table for the acceleration for the TURNING state
-# depending on the current lateral acceleration of the vehicle.
-_TURNING_ACC_V = [0.5, 0., -0.4]  # acc value
-_TURNING_ACC_BP = [1.5, 2.3, 3.]  # absolute value of current lat acc
-
-_LEAVING_ACC = 0.5  # Conformable acceleration to regain speed while leaving a turn.
+_RELIEF_CONFIRMATION_FRAMES = max(1, int(round(0.5 / DT_MDL)))
+_TARGET_RELEASE_RATE = 1.  # m/s^2
+_BELOW_EGO_TARGET_RELEASE_RATE = 3.  # m/s^2
+_MIN_PRED_SPEED = 1.  # m/s
+_MIN_ACTIVATION_SPEED = 10.  # m/s
 
 
 class SmartCruiseControlVision:
@@ -65,13 +57,26 @@ class SmartCruiseControlVision:
     self.state = VisionState.disabled
     self.current_lat_acc = 0.
     self.max_pred_lat_acc = 0.
+    self.relief_frames = 0
+
+  def _v_demand(self) -> float:
+    return max(MIN_V, min(self.v_target, self.v_cruise_setpoint))
+
+  def _released_v_target(self) -> float:
+    demand = self._v_demand()
+    if demand < self.output_v_target:
+      return demand
+    release_rate = _BELOW_EGO_TARGET_RELEASE_RATE if self.output_v_target < min(self.v_ego, demand) else _TARGET_RELEASE_RATE
+    return min(demand, self.output_v_target + release_rate * DT_MDL)
 
   def get_a_target_from_control(self) -> float:
-    return self.a_target
+    return self.a_ego
 
   def get_v_target_from_control(self) -> float:
     if self.is_active:
-      return max(self.v_target, MIN_V) + self.a_target * _NO_OVERSHOOT_TIME_HORIZON
+      if self.output_v_target == V_CRUISE_UNSET:
+        return self._v_demand()
+      return self._released_v_target()
 
     return V_CRUISE_UNSET
 
@@ -82,25 +87,27 @@ class SmartCruiseControlVision:
   def _update_calculations(self, sm: messaging.SubMaster) -> None:
     if not self.long_enabled:
       return
-    else:
-      rate_plan = np.array(np.abs(sm['modelV2'].orientationRate.z))
-      vel_plan = np.array(sm['modelV2'].velocity.x)
 
-      self.current_lat_acc = self.v_ego ** 2 * abs(sm['controlsState'].curvature)
+    rate_plan = np.asarray(np.abs(sm['modelV2'].orientationRate.z), dtype=float)
+    vel_plan = np.asarray(sm['modelV2'].velocity.x, dtype=float)
+    size = min(len(rate_plan), len(vel_plan))
+    rate_plan, vel_plan = rate_plan[:size], vel_plan[:size]
+    valid = np.isfinite(rate_plan) & np.isfinite(vel_plan) & (vel_plan >= _MIN_PRED_SPEED)
 
-      # get the maximum lat accel from the model
-      predicted_lat_accels = rate_plan * vel_plan
-      self.max_pred_lat_acc = np.percentile(predicted_lat_accels, 97)
-
-      # get the maximum curve based on the current velocity
-      v_ego = max(self.v_ego, 0.1)  # ensure a value greater than 0 for calculations
-      max_curve = self.max_pred_lat_acc / (v_ego**2)
-
-      # Get the target velocity for the maximum curve
-      self.v_target = (_A_LAT_REG_MAX / max_curve) ** 0.5
+    self.current_lat_acc = self.v_ego ** 2 * abs(sm['controlsState'].curvature)
+    self.max_pred_lat_acc = 0.
+    self.v_target = V_CRUISE_UNSET
+    if np.any(valid):
+      self.max_pred_lat_acc = float(np.percentile(rate_plan[valid] * vel_plan[valid], 97))
+      max_pred_curvature = float(np.percentile(rate_plan[valid] / vel_plan[valid], 97))
+      if max_pred_curvature > 0.:
+        self.v_target = min(float((_A_LAT_REG_MAX / max_pred_curvature) ** 0.5), V_CRUISE_UNSET)
 
   def _update_state_machine(self) -> tuple[bool, bool]:
     # ENABLED, ENTERING, TURNING, LEAVING, OVERRIDING
+    relief = self.current_lat_acc < _FINISH_LAT_ACC_TH and self.max_pred_lat_acc < _ABORT_ENTERING_PRED_LAT_ACC_TH
+    self.relief_frames = self.relief_frames + 1 if self.state in ACTIVE_STATES and relief else 0
+
     if self.state != VisionState.disabled:
       # longitudinal and feature disable always have priority in a non-disabled state
       if not self.long_enabled or not self.enabled:
@@ -112,7 +119,7 @@ class SmartCruiseControlVision:
         # ENABLED
         if self.state == VisionState.enabled:
           # Do not enter a turn control cycle if the speed is low.
-          if self.v_ego <= MIN_V:
+          if self.v_ego <= _MIN_ACTIVATION_SPEED:
             pass
           # If significant lateral acceleration is predicted ahead, then move to Entering turn state.
           elif self.max_pred_lat_acc >= _ENTERING_PRED_LAT_ACC_TH:
@@ -128,23 +135,26 @@ class SmartCruiseControlVision:
           # Transition to Turning if current lateral acceleration is over the threshold.
           if self.current_lat_acc >= _TURNING_LAT_ACC_TH:
             self.state = VisionState.turning
-          # Abort if the predicted lateral acceleration drops
-          elif self.max_pred_lat_acc < _ABORT_ENTERING_PRED_LAT_ACC_TH:
-            self.state = VisionState.enabled
+          # Begin releasing only after both current and predicted lateral acceleration stay clear.
+          elif self.relief_frames >= _RELIEF_CONFIRMATION_FRAMES:
+            self.state = VisionState.leaving
 
         # TURNING
         elif self.state == VisionState.turning:
-          # Transition to Leaving if current lateral acceleration drops below a threshold.
+          # Transition out of Turning if current lateral acceleration drops below a threshold.
           if self.current_lat_acc <= _LEAVING_LAT_ACC_TH:
-            self.state = VisionState.leaving
+            self.state = VisionState.entering if self.max_pred_lat_acc >= _ENTERING_PRED_LAT_ACC_TH else VisionState.leaving
 
         # LEAVING
         elif self.state == VisionState.leaving:
           # Transition back to Turning if current lateral acceleration goes back over the threshold.
           if self.current_lat_acc >= _TURNING_LAT_ACC_TH:
             self.state = VisionState.turning
-          # Finish if current lateral acceleration goes below a threshold.
-          elif self.current_lat_acc < _FINISH_LAT_ACC_TH:
+          # Start a new turn cycle immediately if another curve is predicted.
+          elif self.max_pred_lat_acc >= _ENTERING_PRED_LAT_ACC_TH:
+            self.state = VisionState.entering
+          # Finish after confirmed relief and a gradual release to the cruise setpoint.
+          elif self.relief_frames >= _RELIEF_CONFIRMATION_FRAMES and self.output_v_target >= self.v_cruise_setpoint:
             self.state = VisionState.enabled
 
     # DISABLED
@@ -157,32 +167,11 @@ class SmartCruiseControlVision:
 
     enabled = self.state in ENABLED_STATES
     active = self.state in ACTIVE_STATES
+    if not active:
+      self.relief_frames = 0
 
     return enabled, active
 
-  def _update_solution(self) -> float:
-    # DISABLED, ENABLED, OVERRIDING
-    if self.state not in ACTIVE_STATES:
-      # when not overshooting, calculate v_turn as the speed at the prediction horizon when following
-      # the smooth deceleration.
-      a_target = self.a_ego
-    # ENTERING
-    elif self.state == VisionState.entering:
-      # when not overshooting, target a smooth deceleration in preparation for a sharp turn to come.
-      a_target = np.interp(self.max_pred_lat_acc, _ENTERING_SMOOTH_DECEL_BP, _ENTERING_SMOOTH_DECEL_V)
-    # TURNING
-    elif self.state == VisionState.turning:
-      # When turning, we provide a target acceleration that is comfortable for the lateral acceleration felt.
-      a_target = np.interp(self.current_lat_acc, _TURNING_ACC_BP, _TURNING_ACC_V)
-    # LEAVING
-    elif self.state == VisionState.leaving:
-      # When leaving, we provide a comfortable acceleration to regain speed.
-      a_target = _LEAVING_ACC
-    else:
-      raise NotImplementedError(f"SCC-V state not supported: {self.state}")
-
-    return a_target
-
   def update(self, sm: messaging.SubMaster, long_enabled: bool, long_override: bool, v_ego: float, a_ego: float,
              v_cruise_setpoint: float) -> None:
     self.long_enabled = long_enabled
@@ -195,7 +184,7 @@ class SmartCruiseControlVision:
     self._update_calculations(sm)
 
     self.is_enabled, self.is_active = self._update_state_machine()
-    self.a_target = self._update_solution()
+    self.a_target = self.a_ego
 
     self.output_v_target = self.get_v_target_from_control()
     self.output_a_target = self.get_a_target_from_control()