Apollo: Question about control conf

[silverland79]

hi:
I have some question about module of control,lincoln.pb.txt.
What are the preview_window's parameters like cf,cr,mass_fl... ?
Please explain the meaning of these parameters,thank you very much.
lat_controller_conf {
ts: 0.01
preview_window: 0
cf: 155494.663
cr: 155494.663
wheelbase: 2.85
mass_fl: 520
mass_fr: 520
mass_rl: 520
mass_rr: 520
eps: 0.01
matrix_q: 0.05
matrix_q: 0.0
matrix_q: 1.0
matrix_q: 0.0
cutoff_freq: 10
mean_filter_window_size: 10
steer_transmission_ratio: 16
steer_single_direction_max_degree: 470
max_iteration: 150
}
lon_controller_conf {
ts: 0.01
brake_deadzone: 15.5
throttle_deadzone: 18.0
speed_controller_input_limit: 2.0
station_error_limit: 2.0
preview_window: 20.0
standstill_acceleration: -3.0
station_pid_conf {
integrator_enable: false
integrator_saturation_level: 0.3
kp: 0.2
ki: 0.0
kd: 0.0
}

[berthu]

These are parameters for the bicycle model of lateral vehicle dynamics, a common dynamic model used for lateral vehicle control. You can learn more about it in "Vehicle Dynamics and Control" by Rajesh Rajamani. The parameters cf and cr are cornering stiffness parameter estimates for the front and rear axle tires. The mass parameters are vehicle mass estimates on each tire. They are separated in order to estimate the inertia moment of the vehicle. Preview window is a more complicated parameter; I believe it is for adjusting an overshooting problem in LQR controllers, using a technique called "Optimal Preview Control".

[silverland79]

Thank you very much.