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86 lines
4.6 KiB
86 lines
4.6 KiB
import math
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import numpy as np
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from cereal import log
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from opendbc.car import FRICTION_THRESHOLD, get_friction
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from opendbc.car.interfaces import LatControlInputs
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from opendbc.car.vehicle_model import ACCELERATION_DUE_TO_GRAVITY
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from openpilot.selfdrive.controls.lib.latcontrol import LatControl
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from openpilot.common.pid import PIDController
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# At higher speeds (25+mph) we can assume:
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# Lateral acceleration achieved by a specific car correlates to
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# torque applied to the steering rack. It does not correlate to
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# wheel slip, or to speed.
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# This controller applies torque to achieve desired lateral
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# accelerations. To compensate for the low speed effects we
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# use a LOW_SPEED_FACTOR in the error. Additionally, there is
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# friction in the steering wheel that needs to be overcome to
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# move it at all, this is compensated for too.
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LOW_SPEED_X = [0, 10, 20, 30]
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LOW_SPEED_Y = [15, 13, 10, 5]
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class LatControlTorque(LatControl):
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def __init__(self, CP, CI):
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super().__init__(CP, CI)
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self.torque_params = CP.lateralTuning.torque.as_builder()
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self.pid = PIDController(self.torque_params.kp, self.torque_params.ki,
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k_f=self.torque_params.kf, pos_limit=self.steer_max, neg_limit=-self.steer_max)
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self.torque_from_lateral_accel = CI.torque_from_lateral_accel()
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self.steering_angle_deadzone_deg = self.torque_params.steeringAngleDeadzoneDeg
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def update_live_torque_params(self, latAccelFactor, latAccelOffset, friction):
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self.torque_params.latAccelFactor = latAccelFactor
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self.torque_params.latAccelOffset = latAccelOffset
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self.torque_params.friction = friction
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def update(self, active, CS, VM, params, steer_limited_by_controls, desired_curvature, curvature_limited):
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pid_log = log.ControlsState.LateralTorqueState.new_message()
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if not active:
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output_torque = 0.0
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pid_log.active = False
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else:
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actual_curvature = -VM.calc_curvature(math.radians(CS.steeringAngleDeg - params.angleOffsetDeg), CS.vEgo, params.roll)
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roll_compensation = params.roll * ACCELERATION_DUE_TO_GRAVITY
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curvature_deadzone = abs(VM.calc_curvature(math.radians(self.steering_angle_deadzone_deg), CS.vEgo, 0.0))
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desired_lateral_accel = desired_curvature * CS.vEgo ** 2
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# desired rate is the desired rate of change in the setpoint, not the absolute desired curvature
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# desired_lateral_jerk = desired_curvature_rate * CS.vEgo ** 2
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actual_lateral_accel = actual_curvature * CS.vEgo ** 2
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lateral_accel_deadzone = curvature_deadzone * CS.vEgo ** 2
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low_speed_factor = np.interp(CS.vEgo, LOW_SPEED_X, LOW_SPEED_Y)**2
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setpoint = desired_lateral_accel + low_speed_factor * desired_curvature
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measurement = actual_lateral_accel + low_speed_factor * actual_curvature
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gravity_adjusted_lateral_accel = desired_lateral_accel - roll_compensation
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torque_from_setpoint = self.torque_from_lateral_accel(LatControlInputs(setpoint, roll_compensation, CS.vEgo, CS.aEgo), self.torque_params,
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gravity_adjusted=False)
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torque_from_measurement = self.torque_from_lateral_accel(LatControlInputs(measurement, roll_compensation, CS.vEgo, CS.aEgo), self.torque_params,
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gravity_adjusted=False)
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pid_log.error = float(torque_from_setpoint - torque_from_measurement)
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ff = self.torque_from_lateral_accel(LatControlInputs(gravity_adjusted_lateral_accel, roll_compensation, CS.vEgo, CS.aEgo), self.torque_params,
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gravity_adjusted=True)
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ff += get_friction(desired_lateral_accel - actual_lateral_accel, lateral_accel_deadzone, FRICTION_THRESHOLD, self.torque_params)
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freeze_integrator = steer_limited_by_controls or CS.steeringPressed or CS.vEgo < 5
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output_torque = self.pid.update(pid_log.error,
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feedforward=ff,
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speed=CS.vEgo,
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freeze_integrator=freeze_integrator)
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pid_log.active = True
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pid_log.p = float(self.pid.p)
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pid_log.i = float(self.pid.i)
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pid_log.d = float(self.pid.d)
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pid_log.f = float(self.pid.f)
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pid_log.output = float(-output_torque)
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pid_log.actualLateralAccel = float(actual_lateral_accel)
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pid_log.desiredLateralAccel = float(desired_lateral_accel)
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pid_log.saturated = bool(self._check_saturation(self.steer_max - abs(output_torque) < 1e-3, CS, steer_limited_by_controls, curvature_limited))
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# TODO left is positive in this convention
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return -output_torque, 0.0, pid_log
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