WinchControllers

Discrete controllers for Winches.

This package is part of Julia Kite Power Tools, which consists of the following packages:

Goals of this package

The goal of this package is to provide controllers for winches that consist of a motor/generator connected to a drum (with or without gearbox). On the drum is a tether that is connected to a load or a kite. Currently operation in air is assumed, but the package could also be extended for winches connected to under-water cables. While the main use case of the author are airborne wind energy systems, I am open to add features needed for other use cases.

Implemented features:

• lower force control (assure that there is always a minimal cable tension)
• upper force control (keep the maximal force limited)
• reel-out speed control proportional to the square root of the force (other relationships can easily be added), either piecewise between the force limits or as a pure kv * sqrt(force) law (WCSettings.mode = "reelout")
• control of asynchronous motors/ generators
• speed control
• auto-tuning of the controller
• disk based stability analysis of linearized system including the force controllers
• torque controlled winches, holding either a length (WinchPosController) or a force (WinchForceController); the length controller has an optional acceleration feed-forward (WCSettings.winch_acc_ff)
• soft force limiting for REEL_OUT mode, a continuous alternative to the upper/lower force controllers (WCSettings.force_limit/soft_lfc): a smoothly saturated inverse of the tension curve, a reel-in line below f_low, an optional low-pass filter of the measured force and an optional soft clamp at the maximal reel-out speed

Planned features

• improved, simplified system model using a quasi-steady tether model and an aerodynamic model including kite mass the cross-wind factor

Installation

Installation of Julia

Install Julia 1.12 or later. If you do not have Julia installed yet, please read Installation.

Installation as package

Installation of WinchControllers as package

It is suggested to use a local Julia environment. You can create it with:

mkdir myproject
cd myproject
julia --project=.

(don't forget typing the dot at the end), and then, on the Julia prompt enter:

using Pkg
pkg"add WinchControllers"

You can run the tests with:

using Pkg
pkg"test WinchControllers"

To add the examples and install the packages needed by the examples, run:

using WinchControllers
WinchControllers.install_examples()
exit()

Installation using git

Installation of WinchControllers using git

In most cases -- if you want to modify, tune and understand kite controllers -- it is better to check out this project from git. You can do this with:

git clone https://github.com/opensourceawe/WinchControllers.jl.git
cd WinchControllers.jl
git checkout v0.6.2

For the checkout command, use the tag of the latest version.

Then run the installation script:

bin/install

It asks which Julia version to use (1.11, 1.12 or 1.13), installs the matching default manifest, instantiates and precompiles the main, examples, test and docs projects and, on Julia 1.12 and 1.13, also runs the tests.

Running the examples

To run the examples, launch Julia with:

bin/run_julia

and then, in the Julia REPL, type:

menu()

Alternatively, launch Julia with julia --project and type include("examples/menu.jl"). You should now see a terminal menu with some examples. Select one using the <cursor up\> and <cursor down\> keys, and press ENTER to run the selected example.

Provides

• a set of generic control components, see Generic Components
• a winch controller WinchController, that limits the upper and lower force and controls the speed as function of the force
• a winch controller settings struct WCSettings for the settings
• Torque Controllers, WinchPosController and WinchForceController, for winches driven by a torque command instead of a speed command
• Utility Functions and Macros

WinchController - Usage -

The WinchController combines the three controllers, mentioned above. It can be operated in two modes of operation:

• speed control
• power production

In speed control mode it requires a set speed as input. Upper and lower force limits are respected. In power production mode it does not require any input but the measured tether force. Output is the set speed of the asynchronous motor.

For a usage example look at the script test_winchcontroller.jl, for the REEL_OUT mode at test_reelout.jl. The winch curve with soft force limiting is plotted by plot_winch_curve.jl.

License

This project is licensed under the MIT License. Please see the below WAIVER in association with the license.

WAIVER

Technische Universiteit Delft hereby disclaims all copyright interest in the package “WinchController.jl” (controllers for airborne wind energy systems) written by the Author(s).

Prof.dr. H.G.C. (Henri) Werij, Dean of Aerospace Engineering

Scientific background

A Methodology for the Design of Kite-Power Control Systems

Related

• Research Fechner for the scientific background of this code
• The meta package KiteSimulators which contains all packages from Julia Kite Power Tools.
• the packages KiteModels and WinchModels and AtmosphericModels
• the package SimpleKiteControllers, which uses the soft force limiting and the torque controllers of this package to fly a single line kite
• the packages KiteViewers and KiteUtils