SpaceX Dragon ISS Docking Autopilot PID Controller in JavaScript | Hacker News Reader

SpaceX Dragon ISS Docking Autopilot PID Controller in JavaScript

18 pointsrzilleruelo21 comments

Here there is a youtube video recording of the controller in action: https://www.youtube.com/watch?v=bH6x3b0McRo

The code can be found here: https://gist.github.com/rzilleruelo/f44252e77036403af4c6a3e85e990c3d

People keep shitting on JavaScript in this thread. To be clear, this is a JavaScript game that SpaceX made, and somebody wrote an autopilot... yes, in JavaScript... because that's what browsers run.

It's a cool algorithm running in the only language browsers natively know to play a browser-native game. Relax. It's cool. It's impressive.

Sometimes I don't even mention that I work with JavaScript or even front end frameworks for fear of triggering some rant from someone frustrating by those topics.

Steps to run the controller:

1. Open the SpaceX simulator: https://iss-sim.spacex.com/.

2. Open the browser javascript console. Example for Google Chrome https://developer.chrome.com/docs/devtools/console/javascrip....

3. Past the code in the gist: https://gist.github.com/rzilleruelo/f44252e77036403af4c6a3e8...

4. Paste this code to start the controller:

  let regimeController = startRegimeController(config);
  let controller = startControl(config);

5. Optionally, you can change the target values to make the controller set the capsule in a different state. For example:

  config.x.target = 0.0;
  config.z.target = 10.0;
  config.pitch.target = -45.0;

IMHO the title is misleading : it's a simulator of ISS Autopilot not the real one.

It was not intentional to be misleading. Though I agree with your comment, the title should be something like "". I tried to change it but it's seems is not longer possible. I'm sorry about that.

SpaceX Dragon ISS Docking Simulator Autopilot PID Controller in JavaScript

JavaScript abuse keeps going on... A language designed for simple browser automation is turning into a plague. It's funny how we bounce from one extreme to another wasting so much effort and focus - many people moved from Java to JavaScript as a revolt against the complexity of the Java ecosystem and specs and laziness to code strongly typed. But look at the JavaScript ecosystem today - with Babel and the JSON libraries, it overshadows the old Java one! Pretty much every Java and XML technology got reinvented and reimplemented in worse ways. And now many replaced JavaScript with TypeScript...

>The controller code is designed to be injected into the SPACEX - ISS Docking Simulator (https://iss-sim.spacex.com/).

What's the problem?

You can run Python in the browser and reuse the code.

What is your point and how does it relate to this project? Seeing as this controller is used in a browser-based simulation, this seems like a perfectly valid use of JavaScript.

In 2021, there are ways to run other languages in the browser - including Python.

You might not like to hear this but it’s probably the Java people that are bringing those ideas to JavaScript.

I find that hard to believe, but maybe the compiler crowd fell in love with the transpiler.

Isn't Javascript terrible for dealing with numerics (floats in particular)?

Dealing with integers is what it's terrible at because it doesn't have them.

    BigInt(5) or 5n

would give you an integer. You can only operate with other integers.

    2n ** 256n === 115792089237316195423570985008687907853269984665640564039457584007913129639936n

Can also work with integers with the likes of: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...

"terrible" depends of what you are trying to do. In this case I would said is good enough to make it work.

Can you provide instructions how to use this? Do I just have to paste it in the chrome console window and go?

Yes no problem. Open the SpaceX simulator. https://iss-sim.spacex.com/

Then open the console and paste the code in the gist. https://gist.github.com/rzilleruelo/f44252e77036403af4c6a3e8...

Then just paste this code to start the controller. let regimeController = startRegimeController(config); let controller = startControl(config);

Also you can change the config on the fly to change the target value, so you can make it do something else if you want.

For example: config.x.target = 0.0; config.z.target = 10.0; config.pitch.target = -45.0;

> Then open the console and paste the code in the gist.

1. Open the SpaceX Simulator webpage[0];

2. Open your browser console (e.g., in Pale Moon browser its in menu "Tools > Web Developer > Web Console" or just type [Ctrl]+[Shift]+[K] shortcut);

3. Copy code from the gist[1] to browser console and execute it;

4. Enjoy

[0] https://iss-sim.spacex.com/

[1] https://gist.github.com/rzilleruelo/f44252e77036403af4c6a3e8...

thank you for providing very clear steps.

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