https://github.com/RhysU/helm

Is the sample solution just hardcoded or is there some maths behind it to make it work from any location/initial speed?

    function controlFunction(block)
    {
      let L = Math.floor;
      let x = block.x;

      // Use Collatz. L(x+½) is the closest integer. 
      return 
        -(L(x+0.5) % 2 === 0
                        ? x/2     // Even, we chop it
                        : 3*x + 1 // Odd, we triple-plus-one it. 
         );
    }

Pretty neat website overall. Seems like I'll be wasting some time on it.

On the "Cruise Control Intro" challenge it's not made clear what the output of the controlFunction is. Am I returning a throttle position? A delta to the throttle position? Something else?

I didn't have any trouble until I got to "Ball on Platform: Balance" which seems to be multiple steps more difficult than the previous ones.

https://backreaction.blogspot.com/2022/12/how-chaos-control-...

I actually made a similar thing based on writing your own autopilot for a Lunar Lander [1]. It's hard to make the difficulty increase linearly though. I like the use of different scenarios in this one.

[1] https://lunar.unnecessarymodification.com/

  function controlFunction(block)
  {
  const max_force=1000000000;
  const margin=0.01;
  const friction_comp=0.2;

  if(block.x<-1-(margin/2))
   return max_force*(1+friction_comp);
  else if(block.x<-1.15*margin)
   return -max_force;
  else
   return -block.x;
}

@ajtulloch might be the world’s leading expert in making 100 billion bucks in 2 months with a device that can be built out of mechanical parts.

function controlFunction(block) { let x = 5; if (block.dx > 0) { x = block.dx; } if (block.T > 1.75) { return 0; } return 2 * x; }

function controlFunction(block) { return -500 * block.x -60 * block.dx; }