carla::traffic_manager::PID Namespace Reference

Functions
float	RelativeVelocityDeviation (const float reference_velocity, const float vehicle_speed, const float target_velocity)
	The target is exactly zero behind a stopped vehicle; the floor avoids a 0/0 NaN that the derivative term would turn into a NaN steering command.
ActuationSignal	RunStep (StateEntry present_state, StateEntry previous_state, const std::vector< float > &longitudinal_parameters, const std::vector< float > &lateral_parameters, const float vehicle_speed, const float control_dt=DT, const float lateral_pursuit_steer=0.0f, const float lateral_damping_scale=1.0f, const float steer_authority_correction=1.0f)
	This function calculates the actuation signals based on the resent state change of the vehicle to minimize PID error.
float	ShapeReferenceVelocity (const float previous_reference, const float vehicle_speed, const float target_velocity, const float control_dt, const bool emergency_stop)
	Reference speed that closes on target_velocity at COMFORT_ACCELERATION instead of stepping to it.
void	SmoothActuation (const StateEntry &previous_state, const float control_dt, const float vehicle_speed, ActuationSignal &actuation_signal)
	A zero pedal demand bypasses the deadband, so pedals rest exactly at zero and nothing here delays a deceleration.

Function Documentation

RelativeVelocityDeviation()

float carla::traffic_manager::PID::RelativeVelocityDeviation ( const float  reference_velocity, const float  vehicle_speed, const float  target_velocity  )

inline

The target is exactly zero behind a stopped vehicle; the floor avoids a 0/0 NaN that the derivative term would turn into a NaN steering command.

Definition at line 50 of file trafficmanager/PIDController.h.

References carla::traffic_manager::constants::MotionPlan::EPSILON_RELATIVE_SPEED.

Referenced by carla::traffic_manager::MotionPlanStage::Update().

RunStep()

ActuationSignal carla::traffic_manager::PID::RunStep ( StateEntry  present_state, StateEntry  previous_state, const std::vector< float > &  longitudinal_parameters, const std::vector< float > &  lateral_parameters, const float  vehicle_speed, const float  control_dt = DT, const float  lateral_pursuit_steer = 0.0f, const float  lateral_damping_scale = 1.0f, const float  steer_authority_correction = 1.0f  )

inline

This function calculates the actuation signals based on the resent state change of the vehicle to minimize PID error.

control_dt is the measured simulation-time period between the two states. The gains are tuned at the nominal DT (sync-mode 0.05 s); in asynchronous mode the real period is one server frame, which under render load (e.g. a path-traced rt_lens sensor) stretches to 2-4x nominal. Left uncompensated that halves the loop's phase margin and the lateral PID goes from damped to divergent weaving (measured on Town12: steer_std 0.11 at 19 fps -> 0.71 with full-lock swings at 11 fps), which then trips the stuck/K-turn recovery into alternating full-lock "jerking". lateral_pursuit_steer replaces the linearized proportional term of the lateral loop: the caller computes the geometric pure-pursuit command atan(wheelbase * margin * 2 sin(alpha) / d) / wheel_lock from the vehicle's own steering geometry, which is exact for every wheelbase and lock where a fixed linear gain is only correct for the car-class fleet it was tuned on. The integral term keeps its original form and units. lateral_damping_scale rescales the derivative term with the loop bandwidth (pursuit-distance schedule x steering-authority correction). steer_authority_correction (>= 1) scales the STEER_LIMIT_GAIN envelope: the envelope is a physical curvature/lateral-acceleration guard, so it must cap curvature, not raw normalized command.

Definition at line 113 of file trafficmanager/PIDController.h.

References carla::traffic_manager::StateEntry::angular_deviation, carla::traffic_manager::constants::PID::MAX_BRAKE, carla::traffic_manager::constants::PID::MAX_CONTROL_DT, carla::traffic_manager::constants::PID::MAX_DEVIATION_RATE, carla::traffic_manager::constants::PID::MAX_STEERING, carla::traffic_manager::constants::PID::MAX_STEERING_RATE, carla::traffic_manager::constants::PID::MAX_THROTTLE, carla::traffic_manager::constants::PID::MIN_CONTROL_DT, carla::traffic_manager::StateEntry::steer, carla::traffic_manager::constants::PID::STEER_LIMIT_GAIN, and carla::traffic_manager::StateEntry::velocity_deviation.

Referenced by carla::traffic_manager::MotionPlanStage::Update().

ShapeReferenceVelocity()

float carla::traffic_manager::PID::ShapeReferenceVelocity ( const float  previous_reference, const float  vehicle_speed, const float  target_velocity, const float  control_dt, const bool  emergency_stop  )

inline

Reference speed that closes on target_velocity at COMFORT_ACCELERATION instead of stepping to it.

After an emergency stop the previous reference is meaningless, so it restarts from the vehicle speed.

Definition at line 29 of file trafficmanager/PIDController.h.

References carla::traffic_manager::constants::PID::COMFORT_ACCELERATION, carla::traffic_manager::constants::PID::MAX_CONTROL_DT, carla::traffic_manager::constants::PID::MIN_CONTROL_DT, and carla::traffic_manager::constants::PID::REFERENCE_LEAD_FRACTION.

Referenced by carla::traffic_manager::MotionPlanStage::Update().

SmoothActuation()

void carla::traffic_manager::PID::SmoothActuation ( const StateEntry &  previous_state, const float  control_dt, const float  vehicle_speed, ActuationSignal &  actuation_signal  )

inline

A zero pedal demand bypasses the deadband, so pedals rest exactly at zero and nothing here delays a deceleration.

Definition at line 61 of file trafficmanager/PIDController.h.

References carla::traffic_manager::ActuationSignal::brake, carla::traffic_manager::StateEntry::brake, carla::traffic_manager::constants::PID::BRAKE_DEADBAND, carla::traffic_manager::constants::PID::LAUNCH_RAMP_SPEED, carla::traffic_manager::constants::PID::MAX_CONTROL_DT, carla::traffic_manager::constants::PID::MAX_LAUNCH_THROTTLE_RISE_RATE, carla::traffic_manager::constants::PID::MIN_CONTROL_DT, carla::traffic_manager::ActuationSignal::steer, carla::traffic_manager::StateEntry::steer, carla::traffic_manager::constants::PID::STEER_DEADBAND, carla::traffic_manager::constants::PID::STEER_DEADBAND_REF_SPEED, carla::traffic_manager::ActuationSignal::throttle, carla::traffic_manager::StateEntry::throttle, and carla::traffic_manager::constants::PID::THROTTLE_DEADBAND.

Referenced by carla::traffic_manager::MotionPlanStage::Update().