The astounding athletic power of quadcopters | Raffaello D'Andrea

Translator: Joseph Geni Reviewer: Morton Bast

Translator: Changbin Lin Reviewer: Bighead Ge

So what does it mean for a machine to be athletic?

如果呢台機器可以做運動 意味著乜嘢？

We will demonstrate the concept of machine athleticism

我哋會借助四旋翼飛行器（四旋翼）

and the research to achieve it

去展示機器運動嘅概念

with the help of these flying machines called quadrocopters,

同埋我哋喺機器運動方面嘅研究

or quads, for short.

Quads have been around for a long time.

四旋翼已經面世好耐

They're so popular these days because they're mechanically simple.

佢哋最近大熱嘅原因 係因為佢哋嘅機械原理簡單

By controlling the speeds of these four propellers,

只要控制呢四個螺旋槳嘅轉速

these machines can roll, pitch, yaw,

呢部機器就可以翻側、俯仰、偏航

and accelerate along their common orientation.

仲可以向任何一個方向加速

On board are also a battery, a computer,

呢部機器有電池、微型電腦 各種傳感器同無線電收發器

various sensors and wireless radios.

Quads are extremely agile, but this agility comes at a cost.

四旋翼靈活係有代價嘅

They are inherently unstable,

佢天生唔夠穩定

and they need some form of automatic feedback control

所以需要自動反饋控制 至保證可以飛得到

in order to be able to fly.

So, how did it just do that?

咁點樣做到自動反饋呢？

Cameras on the ceiling and a laptop

天花板嘅攝像鏡頭同呢部手提電腦

serve as an indoor global positioning system.

形成咗室內嘅定位系統

用嚟定位空間入面嘅物件

It's used to locate objects in the space

that have these reflective markers on them.

每件物件都有呢種反光標記

This data is then sent to another laptop

收集到嘅定位數據會發送去 另一部手提電腦

that is running estimation and control algorithms,

執行估算同控制算法

which in turn sends commands to the quad,

跟住電腦會發送控制指令畀四旋翼

which is also running estimation and control algorithms.

四旋翼亦都會執行計算同控制算法

The bulk of our research is algorithms.

我哋研究嘅重點就係算法

It's the magic that brings these machines to life.

算法賦予呢啲機器活力

So how does one design the algorithms that create a machine athlete?

咁係點樣設計出算法 令機器可以郁嘅呢？

We use something broadly called model-based design.

我哋利用廣義稱為 「以模型為基礎嘅設計方法」

We first capture the physics

我哋首先利用數學模型 掌握機器運動嘅物理數據

with a mathematical model of how the machines behave.

We then use a branch of mathematics called control theory

然後用數學嘅一個細分學科

叫做控制理論，分析模型同合成算法

to analyze these models

and also to synthesize algorithms for controlling them.

從而控制四旋翼

For example, that's how we can make the quad hover.

例如，我哋係咁樣控制四旋翼︰

We first captured the dynamics with a set of differential equations.

首先，用一系列微分方程 掌握佢嘅運動數據

We then manipulate these equations with the help of control theory

藉著控制理論，我哋修改呢啲方程式

to create algorithms that stabilize the quad.

得出一啲算法嚟穩定四旋翼

Let me demonstrate the strength of this approach.

等我示範下呢種方法有幾厲害啦

Suppose that we want this quad to not only hover

假設我哋想四旋翼停喺空中之外

but to also balance this pole.

仲要穩定一轆棍

With a little bit of practice,

經過簡單練習 人類已經可以做到呢個動作

it's pretty straightforward for a human being to do this,

雖然我哋比四旋翼有優勢

although we do have the advantage of having two feet on the ground

我哋可以雙腿掂地

and the use of our very versatile hands.

有好靈活嘅雙手輔助

It becomes a little bit more difficult

但如果我金雞獨立嘅話，咁就有啲難

when I only have one foot on the ground

and when I don't use my hands.

Notice how this pole has a reflective marker on top,

注意轆棍頂部有反光標記 用嚟判斷轆棍嘅空間座標

which means that it can be located in the space.

(Audience) Oh!

（觀眾）哦！

(Applause)

（掌聲）

(Applause ends)

大家可以睇到部四旋翼一直喺度微調

You can notice that this quad is making fine adjustments

令轆棍平衡

to keep the pole balanced.

How did we design the algorithms to do this?

我哋係點樣設計算法搞掂嘅呢？

We added the mathematical model of the pole

我哋將轆棍嘅數學模型輸入到四旋翼

to that of the quad.

Once we have a model of the combined quad-pole system,

只要我哋個模型有齊 四旋翼同轆棍嘅資料

we can use control theory to create algorithms for controlling it.

我哋就可以利用控制理論 建立控制算法去控制四旋翼

Here, you see that it's stable,

睇下，就算我郁佢一下

and even if I give it little nudges,

佢都穩如泰山，都會返到去平衡點

it goes back --

to the nice, balanced position.

We can also augment the model

我哋仲可以修改模型 加入四旋翼預定嘅空間座標

to include where we want the quad to be in space.

Using this pointer, made out of reflective markers,

用著呢條有反光標記嘅指揮棒

I can point to where I want the quad to be in space

就可以點四旋翼去任何我想嘅位置

a fixed distance away from me.

而且同我保持特定嘅距離

（笑聲）

(Laughter)

The key to these acrobatic maneuvers is algorithms,

呢啲特技動作嘅關鍵係算法

designed with the help of mathematical models

算法依賴數學模型同控制理論

and control theory.

Let's tell the quad to come back here

等我指部四旋翼返嚟先

and let the pole drop,

畀四旋翼放低轆棍

and I will next demonstrate the importance

宜家我會講解

理解物理模型 同現實世界運作規律嘅重要

of understanding physical models

and the workings of the physical world.

Notice how the quad lost altitude when I put this glass of water on it.

留意喺我放杯水上去嘅時候

四旋翼嘅高度下降咗

Unlike the balancing pole,

唔似轆棍咁樣

I did not include the mathematical model of the glass

我無喺四旋翼系統度 加入杯水嘅數學模型

in the system.

事實上，系統根本唔知道杯水喺度

In fact, the system doesn't even know that the glass is there.

同之前一樣，我可以用指揮棒 指揮四旋翼嘅走向

Like before, I could use the pointer to tell the quad

where I want it to be in space.

（掌聲）

(Applause)

(Applause ends)

Okay, you should be asking yourself,

大家可能會問 點解玻璃杯嘅水唔會倒出嚟？

why doesn't the water fall out of the glass?

Two facts.

原因有兩個：

The first is that gravity acts on all objects in the same way.

第一，重力對所有物體嘅作用都係一樣

The second is that the propellers

第二，所有螺旋槳都指向 同玻璃杯一樣嘅方向︰指向上

are all pointing in the same direction of the glass, pointing up.

You put these two things together,

呢兩點加埋，結果就係

the net result is that all side forces on the glass are small

杯水打側方向嘅作用力太細

and are mainly dominated by aerodynamic effects,

四旋翼亦因此主要受到空氣動力控制

which at these speeds are negligible.

所以向側邊嘅力都可以忽略

And that's why you don't need to model the glass.

亦因為咁，你無需為玻璃杯整數學模型

It naturally doesn't spill, no matter what the quad does.

因為無論四旋翼做咩，水都唔會漏出嚟

(Audience) Oh!

(Applause)

（掌聲）

(Applause ends)

The lesson here

喺度想講嘅係

is that some high-performance tasks are easier than others,

某啲高性能任務簡單過其他任務

and that understanding the physics of the problem

同埋，理解問题背後嘅物理

tells you which ones are easy and which ones are hard.

你就可以知道邊樣簡單、邊樣難

In this instance, carrying a glass of water is easy.

呢個例子裏面 四旋翼頂住杯水飛就簡單

Balancing a pole is hard.

平衡轆棍就難

We've all heard stories of athletes performing feats while physically injured.

我哋都聽過運動員受傷都可以完成壯舉

Can a machine also perform with extreme physical damage?

咁機器可唔可以 喺極度損壞嘅情況下運作？

Conventional wisdom says

傳統科學認為，你要飛

that you need at least four fixed motor propeller pairs in order to fly,

起碼要四塊固定螺旋槳

because there are four degrees of freedom to control:

因為要控制四範嘢︰ 滾轉、俯仰、偏航同加速

roll, pitch, yaw and acceleration.

Hexacopters and octocopters, with six and eight propellers,

六旋同八旋飛行器 分別有六同八塊螺旋槳

can provide redundancy,

佢哋嘅螺旋槳足以應付所需

but quadrocopters are much more popular

但係四旋更加受歡迎

because they have the minimum number of fixed motor propeller pairs: four.

因為佢有最少嘅螺旋槳：四套

Or do they?

係咪？

(Audience) Oh!

(Laughter)

If we analyze the mathematical model of this machine

如果我哋分析呢台 只用兩個螺旋槳嘅機器嘅數學模型

with only two working propellers,

we discover that there's an unconventional way to fly it.

我哋發現有種新嘅方式可以令佢飛起嚟

We relinquish control of yaw,

就係只要算法容許嘅話

but roll, pitch and acceleration can still be controlled

我哋放棄控制偏航

但係我哋仍然控制滾轉、俯仰同加速

with algorithms that exploit this new configuration.

Mathematical models tell us exactly when and why this is possible.

數學模型精確咁話畀我哋知

幾時同點解呢種配置係有可能

In this instance, this knowledge allows us to design

喺呢個例子，數學模型嘅知識

novel machine architectures

令我哋設計出全新嘅機器結構

或者好似人類運動員一樣聰明 應對損害嘅算法

or to design clever algorithms that gracefully handle damage,

just like human athletes do,

instead of building machines with redundancy.

而無需整多餘嘅部件

We can't help but hold our breath

當我哋睇到跳水運動員空翻入水

when we watch a diver somersaulting into the water,

或者撐杆跳運動員喺空中翻轉

or when a vaulter is twisting in the air,

然後快速著地，我哋一定會屏息以待

the ground fast approaching.

Will the diver be able to pull off a rip entry?

睇下究竟跳水嘅可唔可以壓住水花

Will the vaulter stick the landing?

撐杆跳嘅可唔可以站立著地

Suppose we want this quad here to perform a triple flip

假設我哋希望呢台四旋翼表演三個空翻

and finish off at the exact same spot that it started.

然後停喺佢原來嘅位置

This maneuver is going to happen so quickly

但呢個動作快到

that we can't use position feedback to correct the motion during execution.

我哋用唔到定位反饋信息 糾正執行過程嘅動作

There simply isn't enough time.

時間根本唔夠

Instead, what the quad can do is perform the maneuver blindly,

所以四旋翼只能夠盲目執行動作

observe how it finishes the maneuver,

執行完之後 睇下自己點樣完成呢個動作

and then use that information to modify its behavior

然後修改自己嘅動作

so that the next flip is better.

令到下一個翻轉好啲

Similar to the diver and the vaulter,

呢個類似跳水同撐杆跳運動員

it is only through repeated practice

只有通過反覆練習

that the maneuver can be learned and executed

先可以學好動作，做到最好

to the highest standard.

(Laughter)

(Applause)

（笑聲） （掌聲）

Striking a moving ball is a necessary skill in many sports.

好多運動入面，擊球係一項必須嘅技能

我哋點樣令機器做到 運動員隨便就做到嘅動作？

How do we make a machine do

what an athlete does seemingly without effort?

(Laughter)

（笑聲） （掌聲）

(Applause)

(Applause ends)

This quad has a racket strapped onto its head

呢部四旋翼個頭綁咗塊球拍

with a sweet spot roughly the size of an apple, so not too large.

而最有效擊球點同蘋果差唔多大

所以唔係好大

部機嘅計算頻率係 20 毫秒一次

The following calculations are made every 20 milliseconds,

or 50 times per second.

亦即係每秒 50 次

We first figure out where the ball is going.

我哋第一步睇下個波飛去邊

We then next calculate how the quad should hit the ball

第二步計算出四旋翼要點樣打波

四旋翼收到指令後 就飛去個波飛出嘅位置

so that it flies to where it was thrown from.

Third, a trajectory is planned that carries the quad

第三步，計算出一條從四旋翼 到擊球點嘅飛行軌跡

from its current state to the impact point with the ball.

Fourth, we only execute 20 milliseconds' worth of that strategy.

第四步，我哋只執行 上幾個程序 20 毫秒

Twenty milliseconds later, the whole process is repeated

20 毫秒過去，重複以上成個程序

until the quad strikes the ball.

直到四旋翼打到個波

(Applause)

（掌聲）

Machines can not only perform dynamic maneuvers on their own,

機器唔單止可以獨立運動

they can do it collectively.

佢哋仲可以一齊嚟

These three quads are cooperatively carrying a sky net.

呢三部四旋翼就一齊帶住個球網飛

(Applause)

（掌聲）

(Applause ends)

They perform an extremely dynamic and collective maneuver

佢哋做咗個非常有動態 非常合作嘅操作

to launch the ball back to me.

嚟丟返個波畀我

Notice that, at full extension, these quads are vertical.

注意囉，個網全部打開個陣

呢啲四旋翼全部打側九十度

(Applause)

（掌聲）

In fact, when fully extended,

實際上，當個網全部打開

this is roughly five times greater than what a bungee jumper feels

會產生相當於笨豬跳嘅人 跌到最低時五倍嘅力

at the end of their launch.

The algorithms to do this are very similar

做一齊打波動作嘅算法好簡單

to what the single quad used to hit the ball back to me.

類似一部四旋翼打返個波畀我嘅算式

Mathematical models are used to continuously re-plan

都係利用數學模型持續計算合作策略

a cooperative strategy 50 times per second.

每秒計算 50 次

Everything we have seen so far has been about the machines and their capabilities.

我哋目前睇到嘅所有嘢 都同機器同埋佢哋能力有關

What happens when we couple this machine athleticism

如果我哋將機器嘅運動能力 同人類結合，會點呢？

with that of a human being?

What I have in front of me is a commercial gesture sensor

喺我面前嘅係一部商業用姿勢感應器

mainly used in gaming.

主要用喺遊戲

It can recognize what my various body parts

佢可以實時識別我身體唔同部位嘅動作

are doing in real time.

Similar to the pointer that I used earlier,

而同我之前用嘅指揮棒相似

we can use this as inputs to the system.

我可以用呢個感應器 當成系統嘅輸入裝置

We now have a natural way of interacting

我哋宜家可以用身體姿勢 自然咁同四旋翼互動

with the raw athleticism of these quads with my gestures.

(Applause)

（掌聲）

Interaction doesn't have to be virtual.

互動唔一定係虛擬，可以係現實嘅

It can be physical.

Take this quad, for example.

以呢部四旋翼為例

It's trying to stay at a fixed point in space.

佢想停喺空間嘅一個固定位置

If I try to move it out of the way, it fights me,

如果我要擁開佢，佢會抵抗我

and moves back to where it wants to be.

佢始終會返去佢想要嘅位置度

We can change this behavior, however.

但係，我哋可以改變呢種行為

We can use mathematical models

我哋可以用數學模型 估算我用喺四旋翼上面嘅力

to estimate the force that I'm applying to the quad.

Once we know this force, we can also change the laws of physics,

只要我哋知道呢個力

我哋就可以改變四旋翼嘅物理定律

as far as the quad is concerned, of course.

Here, the quad is behaving as if it were in a viscous fluid.

依家四旋翼就好似喺粘性流體度

We now have an intimate way of interacting with a machine.

而我哋依家可以好親密咁同機器互動

I will use this new capability to position

我會用呢種新技術

將帶住攝像頭嘅四旋翼放喺適當位置

this camera-carrying quad to the appropriate location

for filming the remainder of this demonstration.

去錄低餘下嘅示範

So we can physically interact with these quads

正如頭先所講 我哋可以同四旋翼有實體互動

and we can change the laws of physics.

亦可以改變佢哋嘅物理定律

Let's have a little bit of fun with this.

等我哋嚟玩下呢樣

For what you will see next,

接著落嚟

these quads will initially behave as if they were on Pluto.

你會睇到四旋翼 一開始好似喺太空咁輕飄飄

As time goes on, gravity will be increased

隨住時間增加，引力亦都加大

until we're all back on planet Earth,

直到恢復地球引力為止

but I assure you we won't get there.

但係我保證你同我唔會有事

Okay, here goes.

好，開始

(Laughter)

（笑聲）

(Laughter)

（笑聲）

(Applause)

（掌聲）

Whew!

呼！

你哋一定諗緊四旋翼嘅 開發人員有太多娛樂

You're all thinking now,

these guys are having way too much fun,

and you're probably also asking yourself,

你都可能會問自己

why exactly are they building machine athletes?

點解佢哋要整運動機械人？

Some conjecture that the role of play in the animal kingdom

有人一口咬定話

「玩」嘅功能就係磨練 包括人在內嘅動物嘅技藝同埋能力

is to hone skills and develop capabilities.

Others think that it has more of a social role,

其他人就諗，四旋翼更加有社會功能

that it's used to bind the group.

可以用嚟聚合群體

Similarly, we use the analogy of sports and athleticism

對我哋嚟講

我哋用運動同崇尚運動嘅精神 創造咗新嘅機器算法

to create new algorithms for machines

to push them to their limits.

將機器嘅潛能發揮到極致

What impact will the speed of machines have on our way of life?

機器嘅速度 對我哋嘅生活方式有咩影響？

Like all our past creations and innovations,

同我哋以前所有嘅創造發明一樣

they may be used to improve the human condition

佢哋可能用嚟改善人類嘅生活條件

or they may be misused and abused.

亦都可能俾人誤用或者濫用

This is not a technical choice we are faced with;

我哋面對嘅，唔係技術決定 而係社會決定

it's a social one.

Let's make the right choice,

等我哋做個正確決定

the choice that brings out the best in the future of machines,

令最好嘅機器可以喺將來問世

just like athleticism in sports can bring out the best in us.

就好似崇向運動嘅精神 發掘到運動潛能最勁嘅人咁

Let me introduce you to the wizards behind the green curtain.

等我介紹你哋四旋翼項目 背後勞苦功高嘅人

They're the current members of the Flying Machine Arena research team.

佢哋係飛行器競技場 研究小組嘅現任成員

(Applause)

（掌聲）

Federico Augugliaro, Dario Brescianini,

Federico Augugliaro, Dario Brescianini

Markus Hehn, Sergei Lupashin, Mark Muller and Robin Ritz.

Markus Hehn, Sergei Lupashin

Mark Muller 同 Robin Ritz

Look out for them. They're destined for great things.

請留意佢哋 佢哋日後一定會有偉大嘅成就

Thank you.

多謝大家

(Applause)

（掌聲）