VW MQB: Improved longitudinal starting and stopping

[jyoung8607]

Description

Reduced minimum longitudinal control speeds, for better control at stopping and better responsiveness when starting.

vEgoStopping reduced from 1.0 to 0.5 m/s (car won't reliably slow much more without an explicit stop request) vEgoStarting reduced from 1.0 to 0.1 m/s (with some tweaks to the state machine)

I realize that vEgoStopping is now the interfaces default, but I feel like making it explicit adds clarity when reading the car port code later. I can remove it if you don't care for it.

Verification

Tested on my 2018 Golf R (DSG) and my 2020 Tiguan (Auto), also in vw-community-devel against a few other cars.

Route

d5eb604aa6ae46b7|2023-12-30--23-14-38