PD control

by Bai Shiuan Huang

HTML

<div id="info">PD Control
  <br>Press U or D to move dot<br>
  

KP<input type=range min=50 max=300 id='kp'> 
<br>
KD<input type=range min=0 max=50 id='kd'> <br>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/84/three.min.js"></script>
<script src="https://jyunming-chen.github.io/tutsplus/js/KeyboardState.js"></script>
<script src="https://code.jquery.com/jquery-2.1.4.min.js"></script>

CSS

#info {
  position: absolute;
  top: 0px;
  width: 100%;
  padding: 10px;
  text-align: center;
  color: #ffff00
}

body {
  overflow: hidden;
}

JavaScript

var camera, scene, renderer;
var point;
var keyboard = new KeyboardState();
/////////////////////
var KP = 150;
var KD = 20;
var yy, vv;
var gravity = true;
var yref = -2;

$('#kp').change( function() {
	KP = $(this).val();
});
$('#kd').change( function() {
	KD = $(this).val();
});

init();
animate();

function init() {
  renderer = new THREE.WebGLRenderer({
    antialias: true
  });

  renderer.setSize(window.innerWidth, window.innerHeight);
  renderer.setClearColor(0x888888);
  document.body.appendChild(renderer.domElement);

  scene = new THREE.Scene();
  camera = new THREE.OrthographicCamera(-10, 10, 10, -10, -10, 100);
  camera.position.z = 10;

	//////////////////////////////////////////////////
  var geometry = new THREE.Geometry();
  geometry.vertices.push(
    new THREE.Vector3(-4, 2, 0),
    new THREE.Vector3(4, 2, 0));

  var border = new THREE.Line(geometry, new THREE.LineBasicMaterial({
    color: 0x0000ff
  }));
  var border2 = border.clone();
  border2.position.y = -4;
  scene.add (border2)
  scene.add(border);

  point = new THREE.Mesh(new THREE.CircleGeometry(0.4, 10),
    new THREE.MeshBasicMaterial({
      color: 0xff0000,
    }));
  scene.add(point);

//  window.addEventListener('mousedown', onDocumentMouseDown, false);
	yy = 0;
  vv = 0;
}
/*
function onDocumentMouseDown(event) {
  event.preventDefault();
  // NDC: [-1,1]x[-1,1]
  mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
  mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;

  console.log(mouse.x + ', ' + mouse.y);

  if (event.button === 0) { // left button
    mousePoint.position.set(mouse.x * 50, mouse.y * 50, 0);
  }
}
*/
function feedbackForce () {
	let f = -KP*(yy - yref) - KD*vv;
  return f;
}

function animate() {
	
	var f = feedbackForce();
	if (gravity) //f.add (new THREE.Vector2(0, -9.8));
  	f += (-20.8);
  let dt = 0.01;
  vv += f*dt;
  yy += vv*dt

	point.position.y = yy;
  
  keyboard.update();
  if (keyboard.down('U')) {
  	yref = 2;
  } else if...