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91 lines
4.7 KiB
91 lines
4.7 KiB
import math
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from cereal import log
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from common.numpy_fast import interp
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from selfdrive.controls.lib.latcontrol import LatControl
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from selfdrive.controls.lib.pid import PIDController
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from selfdrive.controls.lib.vehicle_model import ACCELERATION_DUE_TO_GRAVITY
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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
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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.use_steering_angle = self.torque_params.useSteeringAngle
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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, last_actuators, steer_limited, desired_curvature, desired_curvature_rate, llk):
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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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if self.use_steering_angle:
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actual_curvature = -VM.calc_curvature(math.radians(CS.steeringAngleDeg - params.angleOffsetDeg), CS.vEgo, params.roll)
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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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else:
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actual_curvature_vm = -VM.calc_curvature(math.radians(CS.steeringAngleDeg - params.angleOffsetDeg), CS.vEgo, params.roll)
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actual_curvature_llk = llk.angularVelocityCalibrated.value[2] / CS.vEgo
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actual_curvature = interp(CS.vEgo, [2.0, 5.0], [actual_curvature_vm, actual_curvature_llk])
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curvature_deadzone = 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 = 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 - params.roll * ACCELERATION_DUE_TO_GRAVITY
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torque_from_setpoint = self.torque_from_lateral_accel(setpoint, self.torque_params, setpoint,
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lateral_accel_deadzone, friction_compensation=False)
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torque_from_measurement = self.torque_from_lateral_accel(measurement, self.torque_params, measurement,
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lateral_accel_deadzone, friction_compensation=False)
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pid_log.error = torque_from_setpoint - torque_from_measurement
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ff = self.torque_from_lateral_accel(gravity_adjusted_lateral_accel, self.torque_params,
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desired_lateral_accel - actual_lateral_accel,
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lateral_accel_deadzone, friction_compensation=True)
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freeze_integrator = steer_limited 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 = self.pid.p
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pid_log.i = self.pid.i
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pid_log.d = self.pid.d
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pid_log.f = self.pid.f
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pid_log.output = -output_torque
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pid_log.actualLateralAccel = actual_lateral_accel
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pid_log.desiredLateralAccel = desired_lateral_accel
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pid_log.saturated = self._check_saturation(self.steer_max - abs(output_torque) < 1e-3, CS, steer_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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