Torque controller: refactor calculations to be in accel space (#35790)

* clean up

* little confusing but works

* clean up

* fix

* pid outputs torque again, fix windup above max torque

* clean up

* fix

* fix

* typo

* fix conflicts

* fix PID

* cleanups

* seems correct

* updte

* inverse

* whitespace

* move

* small cleanup

* more cleanup

* update ref

---------

Co-authored-by: Bruce Wayne <harald.the.engineer@gmail.com>

common/pid.py

@@ -14,8 +14,7 @@ class PIDController:
     if isinstance(self._k_d, Number):
       self._k_d = [[0], [self._k_d]]
 
-    self.pos_limit = pos_limit
-    self.neg_limit = neg_limit
+    self.set_limits(pos_limit, neg_limit)
 
     self.i_rate = 1.0 / rate
     self.speed = 0.0
@@ -41,6 +40,10 @@ class PIDController:
     self.f = 0.0
     self.control = 0
 
+  def set_limits(self, pos_limit, neg_limit):
+    self.pos_limit = pos_limit
+    self.neg_limit = neg_limit
+
   def update(self, error, error_rate=0.0, speed=0.0, feedforward=0., freeze_integrator=False):
     self.speed = speed
     self.p = float(error) * self.k_p

selfdrive/controls/lib/latcontrol_torque.py

@@ -3,7 +3,6 @@ import numpy as np
 
 from cereal import log
 from opendbc.car.lateral import FRICTION_THRESHOLD, get_friction
-from opendbc.car.interfaces import LatControlInputs
 from openpilot.common.constants import ACCELERATION_DUE_TO_GRAVITY
 from openpilot.selfdrive.controls.lib.latcontrol import LatControl
 from openpilot.common.pid import PIDController
@@ -27,15 +26,22 @@ class LatControlTorque(LatControl):
   def __init__(self, CP, CI):
     super().__init__(CP, CI)
     self.torque_params = CP.lateralTuning.torque.as_builder()
-    self.pid = PIDController(self.torque_params.kp, self.torque_params.ki,
-                             k_f=self.torque_params.kf, pos_limit=self.steer_max, neg_limit=-self.steer_max)
     self.torque_from_lateral_accel = CI.torque_from_lateral_accel()
+    self.lateral_accel_from_torque = CI.lateral_accel_from_torque()
+    self.pid = PIDController(self.torque_params.kp, self.torque_params.ki,
+                             k_f=self.torque_params.kf)
+    self.update_limits()
     self.steering_angle_deadzone_deg = self.torque_params.steeringAngleDeadzoneDeg
 
   def update_live_torque_params(self, latAccelFactor, latAccelOffset, friction):
     self.torque_params.latAccelFactor = latAccelFactor
     self.torque_params.latAccelOffset = latAccelOffset
     self.torque_params.friction = friction
+    self.update_limits()
+
+  def update_limits(self):
+    self.pid.set_limits(self.lateral_accel_from_torque(self.steer_max, self.torque_params),
+                        self.lateral_accel_from_torque(-self.steer_max, self.torque_params))
 
   def update(self, active, CS, VM, params, steer_limited_by_safety, desired_curvature, curvature_limited):
     pid_log = log.ControlsState.LateralTorqueState.new_message()
@@ -57,27 +63,25 @@ class LatControlTorque(LatControl):
       setpoint = desired_lateral_accel + low_speed_factor * desired_curvature
       measurement = actual_lateral_accel + low_speed_factor * actual_curvature
       gravity_adjusted_lateral_accel = desired_lateral_accel - roll_compensation
-      torque_from_setpoint = self.torque_from_lateral_accel(LatControlInputs(setpoint, roll_compensation, CS.vEgo, CS.aEgo), self.torque_params,
-                                                            gravity_adjusted=False)
-      torque_from_measurement = self.torque_from_lateral_accel(LatControlInputs(measurement, roll_compensation, CS.vEgo, CS.aEgo), self.torque_params,
-                                                               gravity_adjusted=False)
-      pid_log.error = float(torque_from_setpoint - torque_from_measurement)
-      ff = self.torque_from_lateral_accel(LatControlInputs(gravity_adjusted_lateral_accel, roll_compensation, CS.vEgo, CS.aEgo), self.torque_params,
-                                          gravity_adjusted=True)
+
+      # do error correction in lateral acceleration space, convert at end to handle non-linear torque responses correctly
+      pid_log.error = float(setpoint - measurement)
+      ff = gravity_adjusted_lateral_accel
       ff += get_friction(desired_lateral_accel - actual_lateral_accel, lateral_accel_deadzone, FRICTION_THRESHOLD, self.torque_params)
 
       freeze_integrator = steer_limited_by_safety or CS.steeringPressed or CS.vEgo < 5
-      output_torque = self.pid.update(pid_log.error,
+      output_lataccel = self.pid.update(pid_log.error,
                                       feedforward=ff,
                                       speed=CS.vEgo,
                                       freeze_integrator=freeze_integrator)
+      output_torque = self.torque_from_lateral_accel(output_lataccel, self.torque_params)
 
       pid_log.active = True
       pid_log.p = float(self.pid.p)
       pid_log.i = float(self.pid.i)
       pid_log.d = float(self.pid.d)
       pid_log.f = float(self.pid.f)
-      pid_log.output = float(-output_torque)
+      pid_log.output = float(-output_torque)  # TODO: log lat accel?
       pid_log.actualLateralAccel = float(actual_lateral_accel)
       pid_log.desiredLateralAccel = float(desired_lateral_accel)
       pid_log.saturated = bool(self._check_saturation(self.steer_max - abs(output_torque) < 1e-3, CS, steer_limited_by_safety, curvature_limited))

selfdrive/controls/tests/test_latcontrol.py

@@ -5,6 +5,7 @@ from opendbc.car.car_helpers import interfaces
 from opendbc.car.honda.values import CAR as HONDA
 from opendbc.car.toyota.values import CAR as TOYOTA
 from opendbc.car.nissan.values import CAR as NISSAN
+from opendbc.car.gm.values import CAR as GM
 from opendbc.car.vehicle_model import VehicleModel
 from openpilot.selfdrive.controls.lib.latcontrol_pid import LatControlPID
 from openpilot.selfdrive.controls.lib.latcontrol_torque import LatControlTorque
@@ -13,7 +14,8 @@ from openpilot.selfdrive.controls.lib.latcontrol_angle import LatControlAngle
 
 class TestLatControl:
 
-  @parameterized.expand([(HONDA.HONDA_CIVIC, LatControlPID), (TOYOTA.TOYOTA_RAV4, LatControlTorque),  (NISSAN.NISSAN_LEAF, LatControlAngle)])
+  @parameterized.expand([(HONDA.HONDA_CIVIC, LatControlPID), (TOYOTA.TOYOTA_RAV4, LatControlTorque),
+                         (NISSAN.NISSAN_LEAF, LatControlAngle), (GM.CHEVROLET_BOLT_EUV, LatControlTorque)])
   def test_saturation(self, car_name, controller):
     CarInterface = interfaces[car_name]
     CP = CarInterface.get_non_essential_params(car_name)

selfdrive/test/process_replay/ref_commit

@@ -1 +1 @@
-4536719353fc9eeb4b9c57692cd72766a2f86397
+6d3219bca9f66a229b38a5382d301a92b0147edb