Revert "exp stop"

This reverts commit e383507ca6.

openpilot/selfdrive/controls/lib/longcontrol.py

@@ -9,8 +9,6 @@ CONTROL_N_T_IDX = ModelConstants.T_IDXS[:CONTROL_N]
 
 LongCtrlState = car.CarControl.Actuators.LongControlState
 
-STOP_JERK = 1.0
-
 
 def long_control_state_trans(CP_SP, active, long_control_state,
                              should_stop, brake_pressed, cruise_standstill):
@@ -55,7 +53,7 @@ class LongControl:
 
   def update(self, active, CS, a_target, should_stop, accel_limits):
     """Update longitudinal control. This updates the state machine and runs a PID loop"""
-    self.pid.neg_limit = max(accel_limits[0], -np.sqrt(2.0 * STOP_JERK * max(CS.vEgo, 0.0)))
+    self.pid.neg_limit = accel_limits[0]
     self.pid.pos_limit = accel_limits[1]
 
     self.long_control_state = long_control_state_trans(self.CP_SP, active, self.long_control_state,
@@ -66,9 +64,11 @@ class LongControl:
       output_accel = 0.
 
     elif self.long_control_state == LongCtrlState.stopping:
-      output_accel = min(self.last_output_accel, 0.0)
-      stop_target = np.interp(CS.vEgo, [0.0, 1.0], [-0.5, self.CP.stopAccel])
-      output_accel = np.clip(stop_target, output_accel - STOP_JERK * DT_CTRL, output_accel + STOP_JERK * DT_CTRL)
+      output_accel = self.last_output_accel
+      if output_accel > self.CP.stopAccel:
+        output_accel = min(output_accel, 0.0)
+        # TODO: can we just go straight to stopAccel?
+        output_accel -= 1.0 * DT_CTRL  # m/s^2/s while trying to stop
       self.reset()
 
     else:  # LongCtrlState.pid