Update README.md

Author: ufechner7

README.md

@@ -9,10 +9,12 @@ This package shall (in the beginning) provide two controllers:
 
 All controllers shall come with an auto-tuning script for tuning the controller parameters for new kites. It might be necessary to run this script for different wind speeds and to create a lookup table that adapts the controller parameters to the wind speed.
 
+The auto-tuning script shall optimize the controller performance in the time domain, using a cost function similar to these [Performance Indicators](https://opensourceawe.github.io/WinchControllers.jl/dev/performance_indicators/). In addition a linearized model shall be used to quantify the stability using the [diskmargin](https://juliacontrol.github.io/RobustAndOptimalControl.jl/dev/api/#RobustAndOptimalControl.diskmargin).
+
 ## This package provides
 - the types `ParkingController` and `ParkingControllerSettings`
 - the functions `linearize`, `calc_steering`, `navigate`
 
 ## TODO
 - add examples for using the parking controller
-- implement a new path following controller for flying figures of eight, see[Fernandes_2022](https://www.mdpi.com/1996-1073/15/4/1390)
+- implement a new path following controller for flying figures of eight, see [Fernandes_2022](https://www.mdpi.com/1996-1073/15/4/1390)