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乐高机器人技术2:齿轮

Beginning Lego Robotics 2: Gears

乐高
Lego
开启机器人的世界
Beginning Robotics
欢迎来到“开启机器人的世界”
Welcome to Beginning Robotics.
这里有一系列视频教你如何更好地制作一个乐高机器人
A series of videos designed to help teach you how to build a better Lego robot.
我是罗杰·布莱恩
My name is Roger Bright.
我是“乐高破坏者”团队的教练
I’m the coach of the Mabry lego destroyers.
“破坏者”团队是位于弗罗里达洲马布里小学的第一支乐高联盟
The destroyers are the first lego league team at Mabry elementary school in Tampa Florida.
所有玩过游戏的人都知道只有玩起来 这个游戏才最有意思
Anyone who’s ever participated in a game knows that the fun of the game lies in playing it.
但是当你“能玩”这个游戏之前
But before you can play a game,
你需要了解游戏规则以及点点滴滴是如何构建起这个游戏的
you have to learn what the rules are and how the pieces work.
这些准则对制作乐高机器人也一样
The same holds true for building a Lego robot.
当你用非常多的时间来把许多乐高元件拼在一起的时候
While you may have spent countless hours putting together many Lego kits,
你可能并没有花时间来弄清楚每个元件或者他们组合一起是起到什么作用的
you may not have spend any time figuring out what each piece does or how they work together.
这就是制作这个视频的目的
That’s what this video is about.
当我们看着发动机的动力从机器人的一个部位传送到另一个部位时
When we watch the transfer the power from one of the motors on our robot from one place to another,
或者当发动机加速或者扭转时 一切都是依靠齿轮来完成的
or increase a motor speed or torque, nothing beats gears.
好吧 如果你看了这个系列的第一个视频 那你就必须看看接下来的东西
Ok. If you watch the first video in this series, then you really had to see this coming.
如果你没看这个系列的第一个视频的话 这就是你的错了
And if you didn’t watch the first video in the series, shame on you.
齿轮就是轮子的一部分 轴承的一个部分 带有一定间隔和规格的齿
A gear is part of a wheel, section of a shaft with cut teeth of spacing in size
用来与另一个齿轮相啮合 从而传送或接受动力
that allows them to mesh with teeth in another part to transfer or receive force and motion.
[鼾声] 不好意思 刚刚讲的是什么
[snoring]I…I’m sorry, what was that?
这就是齿轮 特指直齿轮
These are gears. Specifically spur gears.
直齿轮就是轮子上围绕了一圈坚硬的塑料齿
Spur gears are wheels surrounded by hard plastic teeth.
我们通过齿的数量来区分齿轮
We distinguish the gears by the tooth count.
如果你数了这个齿轮的齿数 你会发现它有八个齿
If you count the teeth on this gear, you will see it has eight teeth,
也就是说也是一个八齿齿轮
which makes it an eight-tooth gear.
乐高机器人主要会用到四种规格的直齿轮
There are four main sizes of spur gears we will be using in Lego robotics–
八齿齿轮
The 8 Tooth,
十六齿齿轮
the 16 Tooth,
二十四齿齿轮
the 24 Tooth,
四十齿齿轮
And the 40 Tooth.
通过把两个或两个以上的齿轮啮合在一起
By meshing two or more gears together
你就可以把发动机放在机器人的一个部位 并且仍然能够使齿轮转动
you can put your motors in one part of the robot and still have them turn wheels
或者使机器人的不同部位运动起来
or activate attachments in a different part of the robot.
除了对齿轮尺寸的描述
In addition to the description of the gear sizes,
还有很多术语是用来指示齿轮的功能的
there are also terms we will be using to indicate the gear’s function.
举个例子 那个直接接收发动机动力的齿轮
For example, the gear that receives energy directly from the power source,
比如这儿的“NXT”发动机 这样的齿轮叫做主动轮
such as our NXT Motor here is called the driver gear.
好吧 在你开始发牢骚之前
Look, before you start groaning.
把这个工作做好是需要大量的努力的
It takes a lot of work to make the jokes this bad.
那个直接接收发动机的动力的齿轮是主动轮
While the gear that receives force directly from the power sources of the driver,
那个从主动轮接收动力的齿轮叫做从动轮
the gear that receives force from the Driver Gear is the Follower Gear.
现在我们花几秒钟时间来看看转动的方向
Now at this point I’d like to take a second and look at the direction of rotation.
从图片中可以看出当主动齿轮按逆时针方向转动
In this picture you can see that when the Driver turns counter clockwise,
会导致从动齿轮顺时针方向转动 也就是相反的方向
it’s going to cause our Follower to turn clockwise, the opposite direction.
现在我们来想一想那个驱动机器人轮子的发动机
Now imagine for a moment that the motor is for the robot’s wheels
并且我想给我的机器人编程
and I want to program my robot
所以发动机的转动方向就是轮子的转动方向
so that the forward direction of my motors is also forward motion for the wheels.
接下来呢
What then?
怎么样才能让从动轮的转动方向和主动轮保持一致呢
How can I make my Follower Gear turn the same direction as my driver?
为了达到这个目的 我用到了中间齿轮
To accomplish this, I use an Idler Gear.
中间齿轮就是用来使主动轮和从动轮转动方向一致的齿轮
An Idler Gear is a gear that is used to keep direction of motion consistent between a driver and a follower.
同样你也可以看出我是用较小的齿轮作为中间齿轮
You can also see that I’m using a smaller gear as my idler.
这个齿轮仅仅就是将动力从主动轮传送到从动轮并限制转动方向的改变
This gear is simply transfering power from my driver to my follower in eliminating the change of direction.
在这样一个装置结构中 中间齿轮是不会改变主动轮和从动轮的力度和转动速度的
Now in this setup, the gear doesn’t change the force or the speed between the driver and my follower,
但并不总是这样
but that’s not always the case.
就像图片中所表达的“我爱速度”
Like the driver of the car in this picture “I love speed”
通过利用不同比例的齿轮
and by using different gear ratios,
还记得第一个视频里谈到的比例吗
remember the ratios from the first video?
我可以提升速度
I can pour on the speed–
我通过增大齿轮数来达到这个目的
“I do this by gearing up”
这就表明主动轮的齿数需要增加
This means that the number of teeth from my Drive Gear would be larger
并大于从动轮的齿的数目
than the number of teeth on my Follower Gear
现在我们有一个二十四齿的主动齿轮与八齿的从动齿轮啮合
Here we have a 24 Tooth Drive Gear meshing with an 8 Tooth follower.
当主动齿轮转动一周时
If our Driver Gear makes one rotation,
从动齿轮就会转动三周
it will cause our follower to make 3 rotations,
主动齿轮上的每一个齿都要和从动齿轮上的每一个齿相啮合
since each individual tooth of the driver has to mesh with the single tooth on our follower.
换言之 就是从动齿轮的转速是主动齿轮的三倍
In other words, our follower’s going 3 times faster than our Drive Gear.
这就是通过齿轮来加速
This is gearing up.
为了决定齿轮的比例
To determine the gear ratio,
我们比较一下齿的数量:主动齿轮-二十四齿
we compared the number of teeth on our Drive Gear––24
对此从动齿轮的齿数-八个齿
to the number of teeth on our follower––8
就给了我们一个比例:24比8
given us a ratio of 24 to 8,
或者化简后的:3比1
or simplifying, 3 to 1.
如果主动齿轮是一个四十齿齿轮
If our Drive Gear was a 40-Tooth gear,
那么比例就会变成5比1
then our ratio would have been 5 to 1.
换言之
In other words,
从动齿轮的转速会是主动齿轮的五倍
our follower would be moving 5 times faster than our Drive Gear.
现在我们假设从动齿轮在一个较大的轮轴上
Now suppose that the follower gear’s on a larger axle,
并且上面有轮子
that also has wheels on it,
那么这个轮轴以及轮子的转速就是主动齿轮的五倍
that axle and those wheels would be going 5 times faster than the Drive Gear.
现在 我要你暂停这个视频
At this point, I want you to stop the video.
讲真的 暂停一下
No, seriously, pause it.
去找一些乐高元件
Go find some Legos,
拿一些齿轮
grab some gears,
以及一些轮轴
and some axles,
实践一下我刚刚说到的“齿轮加速”原理
and play around with the gearing-up concept that I just talked about.
因为再多的理论知识也比不上亲手实践更能让你清晰地了解这个原理
Because no amount of narration can make this any clearer than actual hands–on experimentation.
所以快暂停视频
So go ahead and pause it.
我会一直等你
I will be here when you get back.
除了速度
If instead of speed,
我们也在寻找增加发动机产生的扭转力的方法
we are looking to increase the amount of torque that our motor’s producing
接着我们便会换减速档
then we want a gear down.
在这张图片里面
In this picture,
我们的主动齿轮现在是一个八齿齿轮
our Drive Gear is now an 8 Tooth gear,
而从动齿轮是一个二十四齿齿轮
and our follower is a 24 Tooth gear.
也就是说主动齿轮每转一周
This means that for every rotation our Drive Gear makes,
从动齿轮只会转动三分之一周
our follower will only move 1/3 of a rotation.
我们的齿轮比例现在是1比3
Our gear ratio is now 1 to 3.
好吧 你可以看出它现在转动的更慢了
Ok, you can see it’s moving more slowly.
所以还有什么呢
So what else?
这样做有什么用
What’s the use of this?
为了理解这个部分
To understand this part,
你需要了解扭转力
you need to understand torque,
你还需要知道一件事
and you need to understand one more thing.
[警报]
[warning alert]
这是一个傻瓜警报系统的测试
This is a test of the nerd alert system,
接下来你将会接触到大量的你所不知道的科学接下来知识
you’re about to be exposed to a high levels of scientific nerdiness.
根据能量守恒法则
The scientific Law of Conservation of Energy
能量不能凭空产生或消失
states that energy cannot be created or destroyed,
但是能够改变存在的形式
but can change forms.
对我们来说
In our case,
就是说发动机产生的动力不会因改变随便的生成或消耗
the power from our motor can’t be created or destroyed, just changed
当我们换加速挡时
When we gear up,
视觉上我们会发现速度增大了
we visually see that we are increasing our speed,
但是我们失去的是什么
but what do we lose?
但是如果我们因为换低速挡而降低了速度
And if we lose speed by gearing down,
那这个过程中又产生了什么呢
what is it that we are gaining?
答案就是扭转力
The answer is torque.
从图片上我们可以发现举重在运用力
In our picture we see weightlifter exerting force,
在竖直方向把一个物体向上推动
pushing against an object in a straight direction.
就这个例子来说 这个物体就是重量
In this case, the object being weights.
扭转力 就是一种作用在物体上并使物体转动的力
Torque, is force that’s acting on an object that is rotating,
就像一个轮轴上的轮子
like a wheel on an axle.
来回答我们先前提出的问题
To answer our earlier question,
当我们换低速挡时
when we gear down,
当我们降低速度的时候
when we lose speed,
我们增大了扭转力
we increase torque.
现在我们把八齿齿轮用作主动齿轮
Now that we’ve made our 8-Tooth gear the Drive Gear
把二十四齿齿轮用作从动齿轮
in our 24 Tooth gear the follower,
我们把比例反过来
we have flipped the ratio.
我现在的比例是1比3
We now have a ratio of 1 to 3.
这代表从动齿轮施加的力是主动齿轮的三倍
This means our follower is able to apply 3 times the force as our Drive Gear.
你就会想要按照这个比例来设定你的齿轮
You would want to use a gearing setup like this
或者你的机器人需要的力比发动机所能提供的要多
where your robot needs more strength than the motor has to offer,
比如举起一个重物
such as lifting a heavy object
或者加大机器人轮子的抓地力
or increasing the pushing power of your robot’s wheel’s treads.
就像上次说的
Just like last time,
我想要你暂停一下并实践这个减速档的原理
I want you to stop and experiment with gearing down.
温馨提示
A word of caution, however,
你很轻易就能被一个简易的乐高发动机挤痛
it is really easy to get a nasty pinch from even a simple Lego motor
如果你过多的降低速度
if you gear down too much.
如果你想让从动齿轮的转速是发动机的五倍
Just as you are making your Follower Gear 5 times as fast as the motor
如果你让从动齿轮的转速是发动机的五倍
when gearing up,
那么就把扭转力
you would be increasing the torque,
或者发动机所能提供的力
or the amount of force the motor’s capable of,
提高到了换低速挡的五倍
by 5 times the amount by gearing down in the same way.
这个很容易造成误伤
This can easily result in possible injury.
所以要小心哦
So be careful,
确保父母在旁边以保证安全
and make sure mom or dad are around to be safe.
直到现在我们仅仅用到了直齿轮
Up untill now we’ve only been using spur gears,
还有其他的几种类型的齿轮会在乐高建筑中用到
but there are a few other types of gears that you may want to use in your Lego building.
锥齿轮能够使力的方向转动九十度
Bevel gears allow you to change the direction of force 90 degrees.
举个例子 如果主动齿轮在上面
If your Drive Gear was coming from the top, for example,
但是你想要力度传送到金属推进器骨架的后方
but you wanted to transfer the force to a propeller on the back of your bone,
你会想要用到锥齿轮
you may want to use a pair of bevel gears.
或者你会用到冠齿轮
Or you might want to use a crown gear,
就像现在看到的这个
such as the one seen here.
冠齿轮的齿是向下的
The crown gear’s teeth turned down
促使它能与直齿轮较安全地啮合在一起
and allow it to mesh with the top of a spur gear for a more secure fit.
另一个你经常见到的齿轮就是传动齿轮
Another type of gear you’ll often see is the rack gear.
传动齿轮就是一根上面有齿的平直的条状物
Rack gears are flat bars with teeth on them.
他们可以用作齿轮覆盖的轨道
They can be used as a track for gears to ride on
或者他们可以把转动的扭转力转变为水平方向
or they can transfer rotational torque to force in a straightforward direction.
最后
Lastly,
最后我们要讲的就是蜗轮
the final gear we are going to look at is the worm gear.
我只能说我很抱歉
All I can say is I’m sorry.
蜗蜗轮就是一种有连续的槽而不是齿的特殊齿轮
The worm gear is a special gear that uses a single continuous groove instead of teeth.
当你想要避免滑动时 用蜗轮就很方便了
Worm gears are great to use where you want to avoid slippage.
比如说当你想要举起一些东西的时候
Let’s say that you want to lift something up
并且要确保在你想要降低高度之前会保持在相同的位置不变
and be sure that it will stay there until you want to lower it again.
蜗轮可以转变成一个直齿轮
Since a worm gear can turn a spur gear,
但是直齿轮不能转变成蜗轮
but a spur gear can’t turn a worm gear.
像图片上这样的结构就很完美了
A setup like the one pictured would be perfect.
使用蜗轮的一个缺点就是
A drawback to using worm gears is the fact that
有很大一部分力因为摩擦而损失掉了
there is a lot of energy lost due to friction.
发生在蜗轮的螺旋齿与直齿轮的齿之间的摩擦
The rubbing that occurs between the spiral tooth of the worm in the individual teeth of the spur gear.
这个会造成能量的损失以及齿轮的损坏
This can result in a loss of power and sometimes damage to the gears.
最重要的当然是享受乐趣啊
The most important thing is to HAVE FUN!
要有创造性和实验性
Be creative, experiment.
不论碰到什么问题
No matter what problem you encounter,
不要仅仅就找到答案
don’t just find the solution.
还要享受探索答案的过程
HAVE FUN doing it.

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译制信息
视频概述

原来一个个小小的齿轮还有这么多的科学知识,赶紧一起来get√吧

听录译者

ccz

翻译译者

云树

审核员

Ah~Qiu

视频来源

https://www.youtube.com/watch?v=bWJdVjNgLWw

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