SpaceX Dragon simulator autopilot docking on ISS

iss_spacex_dragon_docking.js

// go to https://iss-sim.spacex.com/
// open browser console and paste this document to enable autopilot
// to disable autopilot:
// clearInterval(a);
let a = setInterval(() => { 
    // retrieve values from simulation
    let roll = fixedRotationZ;
    let pitch = fixedRotationX;
    let yaw = fixedRotationY;
    let rpy = new THREE.Vector3(roll, pitch, yaw);

    let rollRate = -rateRotationZ/10.0;
    let pitchRate = -rateRotationX/10.0;
    let yawRate = -rateRotationY/10.0;

    let rpyRate = new THREE.Vector3(rollRate, pitchRate, yawRate);

    let pos = camera.position.clone();
    let posRate = motionVector.clone();
    let targetPos = issObject.position.clone();

    let targetRpy = new THREE.Vector3(0,0,0);
    let dRpy = targetRpy.clone().sub(rpy);

    // P-controller controls target roll,pitch,yaw-rate (targetRpyRate) to reach target orientation
    let targetRpyRate = new THREE.Vector3(
        dRpy.x/1.0, 
        dRpy.y/1.0, 
        dRpy.z/1.0
    );

    let minRpyRate = new THREE.Vector3(-1.5, -1.5, -1.5);
    let maxRpyRate = new THREE.Vector3(+1.5, +1.5, +1.5);
    targetRpyRate.clamp(minRpyRate, maxRpyRate)

    let dRpyRate = targetRpyRate.clone().sub(rpyRate);

    // console.log(" ");
    // console.log("rpy " + rpy.x + ", " + rpy.y + ", " + rpy.z);
    // console.log("dRpy " + dRpy.x + ", " + dRpy.y + ", " + dRpy.z);
    // console.log("targetRpyRate " + targetRpyRate.x + ", " + targetRpyRate.y + ", " + targetRpyRate.z);
    // console.log("rpyRate " + rpyRate.x + ", " + rpyRate.y + ", " + rpyRate.z);
    // console.log("dRpyRate " + dRpyRate.x + ", " + dRpyRate.y + ", " + dRpyRate.z);

    // don't calculate with displayed x,y,z but the internal coordinates 
    // (z-axis is forward and backward)
    let dPos = targetPos.clone().sub(pos);
    let d = dPos.length();
    // P-controller controls target motion (targetPosRate) to reach target position
    let targetPosRate = new THREE.Vector3(
        dPos.x / 100.0,
        dPos.y / 100.0,
        dPos.z / 100.0
    );
    let minPosRate = new THREE.Vector3(-0.1, -0.1, -0.01);
    let maxPosRate = new THREE.Vector3(+0.1, +0.1, +0.01);

    // thresholds for bang contRol
    let dRpyRateControlThreshold = new THREE.Vector3(0.0, 0.0, 0.0);
    let dPosRateControlThreshold = new THREE.Vector3(0.001, 0.001, 0.001);

    // define some phases where we want to have different movement behaviour

    if (dRpyRate.length() > 0.1)
    {
        // not correctly oriented, stop movement
        targetPosRate.x = 0;
        targetPosRate.y = 0;
        targetPosRate.z = 0;
    }
    else if (Math.abs(dPos.z) < 20)
    {
        // we are very close, slow approach, larger P-control in lateral
        // directions to correct remaining errors
        minPosRate.z = -0.005;
        maxPosRate.z = +0.005;
        dPosRateControlThreshold.x = 0.01;
        dPosRateControlThreshold.y = 0.01;
        targetPosRate.x = dPos.x;
        targetPosRate.y = dPos.y;
    }
    else if (Math.abs(dPos.z) < 50)
    {
        // we are getting, close, slow down
        minPosRate.z = -0.01;
        maxPosRate.z = +0.01;

        minPosRate.x = -0.01;
        minPosRate.y = -0.01;
        maxPosRate.x = +0.01;
        maxPosRate.y = +0.01;
    }
    else if (Math.abs(dPos.z) < 100)
    {
        // slow down
        minPosRate.z = -0.1;
        maxPosRate.z = +0.1;
    }
    else if ((Math.abs(dPos.x) < 0.05) && (Math.abs(dPos.y) < 0.05))
    {
        // lateral position correct, use maximum approaching speed
        minPosRate.z = -0.2;
        maxPosRate.z = +0.2;
    }
    targetPosRate.clamp(minPosRate, maxPosRate);
    let dPosRate = targetPosRate.clone().sub(posRate);
    

    // console.log(" ");
    // console.log("camera.position " + camera.position.x + ", " + camera.position.y + ", " + camera.position.z);
    // console.log("dPos " + dPos.x + ", " + dPos.y + ", " + dPos.z);
    // console.log("targetPosRate " + targetPosRate.x + ", " + targetPosRate.y + ", " + targetPosRate.z);
    // console.log("motionVector " + motionVector.x + ", " + motionVector.y + ", " + motionVector.z);
    // console.log("dPosRate " + dPosRate.x + ", " + dPosRate.y + ", " + dPosRate.z);
    
    // bang control to reach target roll pitch and yaw rate
    if (dRpyRate.x < -dRpyRateControlThreshold.x)
        rollRight();
    else if (dRpyRate.x > +dRpyRateControlThreshold.x)
        rollLeft();
    if (dRpyRate.y < -dRpyRateControlThreshold.y)
        pitchDown();
    else if (dRpyRate.y > +dRpyRateControlThreshold.y)
        pitchUp();
    if (dRpyRate.z < -dRpyRateControlThreshold.z)
        yawRight();
    else if (dRpyRate.z > +dRpyRateControlThreshold.z)
        yawLeft();

    // bang control to reach target motion
    if (dPosRate.x < -dPosRateControlThreshold.x)
        translateLeft();
    else if (dPosRate.x > +dPosRateControlThreshold.x)
        translateRight();
    if (dPosRate.y < -dPosRateControlThreshold.y)
        translateDown();
    else if (dPosRate.y > +dPosRateControlThreshold.y)
        translateUp();
    if (dPosRate.z < -dPosRateControlThreshold.z)
        translateForward();
    else if (dPosRate.z > +dPosRateControlThreshold.z)
        translateBackward();

},100);