From fc4e5007fd55784a5aaf471744f431baa11b118f Mon Sep 17 00:00:00 2001
From: felsager <76905857+felsager@users.noreply.github.com>
Date: Thu, 30 Oct 2025 13:29:38 -0700
Subject: [PATCH] latcontrol_torque: make feed-forward jerk independent of
 individual platform lag (#36334)

---
 selfdrive/controls/lib/latcontrol_torque.py | 19 ++++++++++++-------
 selfdrive/test/process_replay/ref_commit    |  2 +-
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/selfdrive/controls/lib/latcontrol_torque.py b/selfdrive/controls/lib/latcontrol_torque.py
index 443fd1851c..1e3d80c2d5 100644
--- a/selfdrive/controls/lib/latcontrol_torque.py
+++ b/selfdrive/controls/lib/latcontrol_torque.py
@@ -27,8 +27,10 @@ INTERP_SPEEDS = [1, 1.5, 2.0, 3.0, 5, 7.5, 10, 15, 30]
 KP_INTERP = [250, 120, 65, 30, 11.5, 5.5, 3.5, 2.0, KP]
 
 LP_FILTER_CUTOFF_HZ = 1.2
+JERK_LOOKAHEAD_SECONDS = 0.19
+JERK_GAIN = 0.3
 LAT_ACCEL_REQUEST_BUFFER_SECONDS = 1.0
-VERSION = 0
+VERSION = 0 # bump this when changing controller
 
 class LatControlTorque(LatControl):
   def __init__(self, CP, CI, dt):
@@ -39,10 +41,12 @@ class LatControlTorque(LatControl):
     self.pid = PIDController([INTERP_SPEEDS, KP_INTERP], KI, KD, rate=1/self.dt)
     self.update_limits()
     self.steering_angle_deadzone_deg = self.torque_params.steeringAngleDeadzoneDeg
+    self.lookahead_frames = int(JERK_LOOKAHEAD_SECONDS / self.dt)
     self.lat_accel_request_buffer_len = int(LAT_ACCEL_REQUEST_BUFFER_SECONDS / self.dt)
     self.lat_accel_request_buffer = deque([0.] * self.lat_accel_request_buffer_len , maxlen=self.lat_accel_request_buffer_len)
-    self.previous_measurement = 0.0
+    self.jerk_filter = FirstOrderFilter(0.0, 1 / (2 * np.pi * LP_FILTER_CUTOFF_HZ), self.dt)
     self.measurement_rate_filter = FirstOrderFilter(0.0, 1 / (2 * np.pi * LP_FILTER_CUTOFF_HZ), self.dt)
+    self.previous_measurement = 0.0
 
   def update_live_torque_params(self, latAccelFactor, latAccelOffset, friction):
     self.torque_params.latAccelFactor = latAccelFactor
@@ -68,25 +72,26 @@ class LatControlTorque(LatControl):
 
       delay_frames = int(np.clip(lat_delay / self.dt, 1, self.lat_accel_request_buffer_len))
       expected_lateral_accel = self.lat_accel_request_buffer[-delay_frames]
-      # TODO factor out lateral jerk from error to later replace it with delay independent alternative
+      lookahead_idx = int(np.clip(-delay_frames + self.lookahead_frames, -self.lat_accel_request_buffer_len+1, -2))
+      raw_lateral_jerk = (self.lat_accel_request_buffer[lookahead_idx+1] - self.lat_accel_request_buffer[lookahead_idx-1]) / (2 * self.dt)
+      desired_lateral_jerk = self.jerk_filter.update(raw_lateral_jerk)
       future_desired_lateral_accel = desired_curvature * CS.vEgo ** 2
       self.lat_accel_request_buffer.append(future_desired_lateral_accel)
       gravity_adjusted_future_lateral_accel = future_desired_lateral_accel - roll_compensation
-      desired_lateral_jerk = (future_desired_lateral_accel - expected_lateral_accel) / lat_delay
+      setpoint = expected_lateral_accel
 
       measurement = measured_curvature * CS.vEgo ** 2
       measurement_rate = self.measurement_rate_filter.update((measurement - self.previous_measurement) / self.dt)
       self.previous_measurement = measurement
 
-      setpoint = lat_delay * desired_lateral_jerk + expected_lateral_accel
-      error = setpoint - measurement
+      error = setpoint - measurement + JERK_GAIN * desired_lateral_jerk
 
       # do error correction in lateral acceleration space, convert at end to handle non-linear torque responses correctly
       pid_log.error = float(error)
       ff = gravity_adjusted_future_lateral_accel
       # latAccelOffset corrects roll compensation bias from device roll misalignment relative to car roll
       ff -= self.torque_params.latAccelOffset
-      # TODO jerk is weighted by lat_delay for legacy reasons, but should be made independent of it
+      # TODO remove lateral jerk from feed forward - moving it from error means jerk is not scaled by low speed factor
       ff += get_friction(error, lateral_accel_deadzone, FRICTION_THRESHOLD, self.torque_params)
 
       freeze_integrator = steer_limited_by_safety or CS.steeringPressed or CS.vEgo < 5
diff --git a/selfdrive/test/process_replay/ref_commit b/selfdrive/test/process_replay/ref_commit
index cdd4301fcf..37d1e8f8d3 100644
--- a/selfdrive/test/process_replay/ref_commit
+++ b/selfdrive/test/process_replay/ref_commit
@@ -1 +1 @@
-b508f43fb0481bce0859c9b6ab4f45ee690b8dab
\ No newline at end of file
+9a7d8dd0660ba6a344ac61be89b2e832e6756184
\ No newline at end of file