freneticlib.executors.bicycle.controller

This module contains PID controllers to perform lateral and longitudinal control.

Module Contents

Classes

VehiclePIDController	VehiclePIDController is the combination of two PID controllers
PIDLongitudinalController	PIDLongitudinalController implements longitudinal control using a PID.
PIDLateralController	PIDLateralController implements lateral control using a PID.

class freneticlib.executors.bicycle.controller.VehiclePIDController(vehicle, args_lateral, args_longitudinal, offset=0, max_throttle=0.75, max_brake=0.3, max_steering=0.8)

VehiclePIDController is the combination of two PID controllers (lateral and longitudinal) to perform the low level control a vehicle from client side

Constructor method.

Parameters:

• vehicle – actor to apply to local planner logic onto

• args_lateral – dictionary of arguments to set the lateral PID controller

using the following semantics:

K_P – Proportional term K_D – Differential term K_I – Integral term

Parameters:

args_longitudinal – dictionary of arguments to set the longitudinal

PID controller using the following semantics:

K_P – Proportional term K_D – Differential term K_I – Integral term

Parameters:

offset – If different than zero, the vehicle will drive displaced from the center line.

Positive values imply a right offset while negative ones mean a left one. Numbers high enough to cause the vehicle to drive through other lanes might break the controller.

run_step(target_speed, waypoint)

Execute one step of control invoking both lateral and longitudinal PID controllers to reach a target waypoint at a given target_speed.

param target_speed:

desired vehicle speed

param waypoint:

target location encoded as a waypoint

return:

distance (in meters) to the waypoint

change_longitudinal_PID(args_longitudinal)

Changes the parameters of the PIDLongitudinalController

change_lateral_PID(args_lateral)

Changes the parameters of the PIDLongitudinalController

class freneticlib.executors.bicycle.controller.PIDLongitudinalController(vehicle, K_P=1.0, K_I=0.0, K_D=0.0, dt=0.03)

PIDLongitudinalController implements longitudinal control using a PID.

Constructor method.

param vehicle:

actor to apply to local planner logic onto

param K_P:

Proportional term

param K_D:

Differential term

param K_I:

Integral term

param dt:

time differential in seconds

run_step(target_speed, debug=False)

Execute one step of longitudinal control to reach a given target speed.

param target_speed:

target speed in Km/h

param debug:

boolean for debugging

return:

throttle control

_pid_control(target_speed, current_speed)

Estimate the throttle/brake of the vehicle based on the PID equations

param target_speed:

target speed in Km/h

param current_speed:

current speed of the vehicle in Km/h

return:

throttle/brake control

change_parameters(K_P, K_I, K_D, dt)

Changes the PID parameters

class freneticlib.executors.bicycle.controller.PIDLateralController(vehicle, offset=0, K_P=1.0, K_I=0.0, K_D=0.0, dt=0.03)

PIDLateralController implements lateral control using a PID.

Constructor method.

param vehicle:

actor to apply to local planner logic onto

param offset:

distance to the center line. If might cause issues if the value is large enough to make the vehicle invade other lanes.

param K_P:

Proportional term

param K_D:

Differential term

param K_I:

Integral term

param dt:

time differential in seconds

run_step(waypoint)

Execute one step of lateral control to steer the vehicle towards a certain waypoin.

param waypoint:

target waypoint

return:

steering control in the range [-1, 1] where:

-1 maximum steering to left +1 maximum steering to right

_pid_control(waypoint, vehicle_transform)

Estimate the steering angle of the vehicle based on the PID equations

param waypoint:

target waypoint

param vehicle_transform:

current transform of the vehicle

return:

steering control in the range [-1, 1]

change_parameters(K_P, K_I, K_D, dt)

Changes the PID parameters