These Bots AreMade For Walkin’

jsconf.co October 16, 2015

Donovan Buck

dtex

• JavaScript robotics. Specifically it’s about Johnny-Five
• The first time I saw NodeConf in 2012.
• Attended nodebotsday 2013.
• I decided to build my own robot… and I wanted a walking robot.
• But I discovered something…

WalkingIs Hard!

DARPA Robotics Challenge

• The robot has to maintain its balance.
• This can be done with Static or Dynamic gaits
• Static gaits are those where the center of gravity
• Dynamic gaits are the opposite

Robot Anatomy

Robot Anatomy

Drunk Robot

• End effector describes a circle around the coxa axis of rotation
• Legs are working against each other
• We want them to work together and move the robot forward smoothly, in a straight line.

Sober Robot

• To do this we have to move all three joints in concert
• That’s a whole lot of stuff that needs to happen.
• Is it even possible?

Rick Waldron

@rwaldron

• In May of 2014 Rick Waldron presented at EmpireJS
• Bits of Nodebots Next
• Showing some things that were possible with Johnny-Five

Bits of NodeBots Next

• 12 Servos, 100fps = 9,600 commands in this 8 second clip
• node.js -> Johnny Five -> Firmata -> Node Serialport -> Firmata -> Arduino
• It works!
• Rick had to create his animation from scratch

Animation()

• Timeline
• Cue Points & Key Frames
• Tweening
• Easing Functions

• Metaphors from 2D and 3D animation apps
• I’m going to show some Animation code real quick.

Using Animation()

var five = require("johnny-five");
var board = new five.Board().on("ready", function() {

  var right = new five.Servo(11),
      left = new five.Servo(10);

  var legs = new five.Servo.Array([right, left]);
  var legsAnimation = new five.Animation(legs);

  legsAnimation.enqueue({
    duration: 5000,
    easing: "inOutQuad",
    cuePoints: [ 0, 0.25, 0.5, 0.6, 1.0],
    keyFrames: [
      [null, {degrees: 110}, -90, false, {degrees: 0}],
      [null, {degrees: 90}, 20, -90, {degrees: 140}]
    ]
  });
});

• Require J5, Create a board
• The magical handshake
• Create servos. First point:
• Servo array = target, Animation = timeline
• Enqueue segment
• Pretty easy right?

Using Animation()

keyFrames: [
  [null, null, {degrees: s.f.c[5]}, null, null, null, null, {degrees: s.f.c[5]}, null, {degrees: s.f.c[0]}, null, null, null, null, {degrees: s.f.c[5]}], // r1c
  [null, { step: lift.femur, easing: easeOut }, {degrees: s.f.f[5], easing: easeIn}, null, null, null, null, {degrees: s.f.f[5]}, { step: lift.femur, easing: easeOut }, {degrees: s.f.f[0], easing: easeIn}, null, null, null, null, {degrees: s.f.f[5]}],
  [null, { step: lift.tibia, easing: easeOut }, {degrees: s.f.t[5], easing: easeIn}, null, null, null, null, {degrees: s.f.t[5]}, { step: lift.tibia, easing: easeOut }, {degrees: s.f.t[0], easing: easeIn}, null, null, null, null, {degrees: s.f.t[5]}],

  [null, null, null, false, null, {degrees: s.f.c[2]}, null, {degrees: s.f.c[2]}, null, null, {degrees: s.f.c[5]}, null, {degrees: s.f.c[0]}, null, {degrees: s.f.c[2]}],
  [null, null, null, false, { step: lift.femur, easing: easeOut }, {degrees: s.f.f[2], easing: easeIn}, null, {degrees: s.f.f[2]}, null, null, {degrees: s.f.f[5]}, { step: lift.femur, easing: easeOut }, {degrees: s.f.f[0], easing: easeIn}, null, {degrees: s.f.f[2]}],
  [null, null, null, false, { step: lift.tibia, easing: easeOut }, {degrees: s.f.t[2], easing: easeIn}, null, {degrees: s.f.t[2]}, null, null, {degrees: s.f.t[5]}, { step: lift.tibia, easing: easeOut }, {degrees: s.f.t[0], easing: easeIn}, null, {degrees: s.f.t[2]}],

  [null, null, null, null, false, null, {degrees: s.m.c[1]}, {degrees: s.m.c[1]}, null, null, null, {degrees: s.m.c[5]}, null, {degrees: s.m.c[0]}, {degrees: s.m.c[1]}],
  [null, null, null, null, false, { step: lift.femur, easing: easeOut }, {degrees: s.m.f[1], easing: easeIn}, {degrees: s.m.f[1]}, null, null, null, {degrees: s.m.f[5]}, { step: lift.femur, easing: easeOut }, {degrees: s.m.f[0], easing: easeIn}, {degrees: s.m.f[1]}],
  [null, null, null, null, false, { step: lift.tibia, easing: easeOut }, {degrees: s.m.t[1], easing: easeIn}, {degrees: s.m.t[1]}, null, null, null, {degrees: s.m.t[5]}, { step: lift.tibia, easing: easeOut }, {degrees: s.m.t[0], easing: easeIn}, {degrees: s.m.t[1]}],

  [null, false, null, {degrees: s.m.c[4]}, null, null, null, {degrees: s.m.c[4]}, {degrees: s.m.c[5]}, null, {degrees: s.m.c[0]}, null, null, null, {degrees: s.m.c[4]}],
  [null, false, { step: lift.femur, easing: easeOut }, {degrees: s.m.f[4], easing: easeIn}, null, null, null, {degrees: s.m.f[4]}, {degrees: s.m.f[5]}, { step: lift.femur, easing: easeOut }, {degrees: s.m.f[0], easing: easeIn}, null, null, null, {degrees: s.m.f[4]}],
  [null, false, { step: lift.tibia, easing: easeOut }, {degrees: s.m.t[4], easing: easeIn}, null, null, null, {degrees: s.m.t[4]}, {degrees: s.m.t[5]}, { step: lift.tibia, easing: easeOut }, {degrees: s.m.t[0], easing: easeIn}, null, null, null, {degrees: s.m.t[4]}],

  [null, null, false, null, {degrees: s.r.c[3]}, null, null, {degrees: s.r.c[3]}, null, {degrees: s.r.c[5]}, null, {degrees: s.r.c[0]}, {degrees: s.r.c[1]}, null, {degrees: s.r.c[3]}],
  [null, null, false, { step: lift.femur, easing: easeOut }, {degrees: s.r.f[3], easing: easeIn}, null, null, {degrees: s.r.f[3]}, null, {degrees: s.r.f[5]}, { step: lift.femur, easing: easeOut }, {degrees: s.r.f[0], easing: easeIn}, {degrees: s.r.f[1]}, null, {degrees: s.r.f[3]}],
  [null, null, false, { step: lift.tibia, easing: easeOut }, {degrees: s.r.t[3], easing: easeIn}, null, null, {degrees: s.r.t[3]}, null, {degrees: s.r.t[5]}, { step: lift.tibia, easing: easeOut }, {degrees: s.r.t[0], easing: easeIn}, {degrees: s.r.t[1]}, null, {degrees: s.r.t[3]}],

  [null, null, null, null, null, false, null, {degrees: s.r.c[0]}, null, null, null, null, {degrees: s.r.c[5]}, null, {degrees: s.r.c[0]}],
  [null, null, null, null, null, false, { step: lift.femur, easing: easeOut }, {degrees: s.r.f[0], easing: easeIn}, null, null, null, null, {degrees: s.r.f[5]}, { step: lift.femur, easing: easeOut }, {degrees: s.r.f[0], easing: easeIn}],
  [null, null, null, null, null, false, { step: lift.tibia, easing: easeOut }, {degrees: s.r.t[0], easing: easeIn}, null, null, null, null, {degrees: s.r.t[5]}, { step: lift.tibia, easing: easeOut }, {degrees: s.r.t[0], easing: easeIn}]
]

• This is terrible
• It's the keyframe array for a simple walking sequence
• Incredibly tedious and error prone

Divide by Zero

legs.to(Infinity);

• Easy to make mistakes
• Could have cost hundreds of dollars

Ronald Jaramillo

@ronaldxjt

• Ronald Jaramillo created Go-Johnny-Go
• A nice GUI for building J5 animations

Go-Johnny-Go

• Define cuepoint
• Define keyframes
• Playback
• Export

Animation()

• Using a leap motion controller.
• Wake, walk, turn, reverse, sleep
• Pretty cool… Not cool.
• Explicitly telling every limb what to do
• Without regard to the robot’s environment.
• Setting the angle of each servo
• We are not putting our end effectors where they might actually need to be.
• This is a fancy remote controlled toy
• We want robots that can be aware of their environment, respond to changing conditions and do the tasks we give them in a “smart” way.

More Bits ofNodebots Next

• We need to be able to map the environment in more detail and at a much farther range.
• We need to be able to do way finding.
• First we need to be able to position our end effectors in a way that is not predetermined.

The Next Dimension

• Joint coordinate space
• Now we’re dealing with points in global coordinate space.
• Instead of a single degree value we are working with three-tuples… X,Y and Z coordinates.
• Animation() handles that.
• But we needed a way to position the end effectors.

Raquel Vélez

@rockbot

• Demoed Manny-The-Manipulator at JSConf in 2013.
• At Manny’s heart was Vektor
• A suite of linear algebra tools for helping with inverse kinematics.
• What is inverse kinematics

Manny the Manipulator

Forward Kinematics

• We take a series of known values (our segment lengths and joint angles)
• Calculate where the end effector will be.
• In this example Raquel is positioning the servos, and the end effector position is being calculated.

Manny the Manipulator

Inverse Kinematics

• We are given the desired end effector position and joint lengths
• We have to find the angles that get our end effector to that point.
• In this example Raquel is dragging the end effector and the angles are being calculated.
• Vector gives us tools to help solve for that. But we still needed a way to define our kinematic chains.

Tharp

• A node module that allows us to define kinematic chains, systems of chains (robots).
• Tharp takes in an end effector position and segment lengths then spits out servo angles.

Using Tharp Chains

var r1 = new Tharp.Chain({
  chainType: "CoxaY-FemurZ-TibiaZ",
  origin: [4.25, 2.875, 8.15],
  segments: { femur: 7.6125, tibia: 10.4 },
  startAt: [11.25, 0, 12.15],
  constructor: five.Servos,
  actuators: [
    { pin: 40, offset: 24, startAt: 0, range: [0, 90] },
    { pin: 39, offset: 87, startAt: 78, range: [-80, 78] },
    { pin: 38, offset: 165, invert: true, startAt: -140, range: [-160, -10] }
  ]
});

• Define a kinematic chain
• Select chain type, Define origin point, Set segment lengths, Set start position Define actuators

Using Tharp Robots

var phoenix = new Tharp.Robot({
  robotType: "hexapod",
  chains: [r1, l1, r2, l2, r3, l3]
});

• Define a robot
• Select robot type
• Define chains
• Now we have everything we need to set an X,Y,Z coordinate on a chain and Johnny-Five will put the end effector there.

Tharp

• Our first movement is a “wake up” animation segment
• Instead of tweening between angles we are tweening between XYZ tuples.
• Show palm movement.
• Now here, we are not using animation(). We have rotation about all three axes, and translation along all three axes while maintaining our end effector positions in global coordinate space.
• Next steps for Tharp are support for more chain, and robot types. We also want to wrap a variety of gaits into Tharp for each robot type.

Johnny-Fiveis Awesome!

• Johnny-Five is amazing.
• It takes hard things and makes them incredibly easy.
• Almost anyone can get up and running with robotics in an afternoon.
• Connected by Default
• Embeddable (Pi, T2, Edison, BBB)

The Communityis Awesome!

• Remarkably Diverese
• International
• Friendly
• Accomodating
• 86 Contributors
• You Should Join Us!

• Remarkably diverese team
• 86 Contributors/li>
• Friendly & Helpful

The Futureis Awesome!

JerryScript

V7

• As JavaScript developers our range of influence is growing
• What’s expected from us will change
• I promise that unless you are retiring soon you will have opportunities to build for other types of hardware
• The time you spend playing with Nodebots will pay off.

Links

johnny-five.io

github.com/Traverso/go-johnny-go

github.com/rockbot/vektor

github.com/dtex/tharp

dtex

• Thanks for Listening

Go Be Awesome!

dtex.us/jsconfco

dtex

• Thanks for Listening