FCW: less false positives (#26366)

* Less FP for FCW

* enable fcw for e2e long
old-commit-hash: 253e5d7f9d7741e61f010f2ffd6b82a2e908019a

selfdrive/controls/lib/longitudinal_mpc_lib/long_mpc.py

@@ -36,7 +36,7 @@ A_EGO_COST = 0.
 J_EGO_COST = 5.0
 A_CHANGE_COST = 200.
 DANGER_ZONE_COST = 100.
-CRASH_DISTANCE = .5
+CRASH_DISTANCE = .25
 LEAD_DANGER_FACTOR = 0.75
 LIMIT_COST = 1e6
 ACADOS_SOLVER_TYPE = 'SQP_RTI'
@@ -49,6 +49,7 @@ MAX_T = 10.0
 T_IDXS_LST = [index_function(idx, max_val=MAX_T, max_idx=N) for idx in range(N+1)]
 
 T_IDXS = np.array(T_IDXS_LST)
+FCW_IDXS = T_IDXS < 5.0
 T_DIFFS = np.diff(T_IDXS, prepend=[0.])
 MIN_ACCEL = -3.5
 MAX_ACCEL = 2.0
@@ -369,7 +370,7 @@ class LongitudinalMpc:
     self.params[:,4] = T_FOLLOW
 
     self.run()
-    if (np.any(lead_xv_0[:,0] - self.x_sol[:,0] < CRASH_DISTANCE) and
+    if (np.any(lead_xv_0[FCW_IDXS,0] - self.x_sol[FCW_IDXS,0] < CRASH_DISTANCE) and
             radarstate.leadOne.modelProb > 0.9):
       self.crash_cnt += 1
     else:

selfdrive/controls/lib/longitudinal_planner.py

@@ -132,8 +132,7 @@ class LongitudinalPlanner:
     self.j_desired_trajectory = np.interp(T_IDXS[:CONTROL_N], T_IDXS_MPC[:-1], self.mpc.j_solution)
 
     # TODO counter is only needed because radar is glitchy, remove once radar is gone
-    # TODO write fcw in e2e_long mode
-    self.fcw = self.mpc.mode == 'acc' and self.mpc.crash_cnt > 5 and not sm['carState'].standstill
+    self.fcw = self.mpc.crash_cnt > 2 and not sm['carState'].standstill
     if self.fcw:
       cloudlog.info("FCW triggered")