未登录,请登录后再发表信息
最新评论 (0)
播放视频

了解防抱死系统

Understanding Anti-lock Braking System (ABS) !

现如今 ABS – 防抱死制动系统
Nowadays, an anti-lock braking system
几乎被用到了所有汽车中
is used in almost all modern vehicles.
该系统能防止像这样的事故
This system prevents accidents like this,
即当你在使用刹车时
where you lose control of the steering
无法同时控制方向
as you apply the brakes.
有了ABS 你就能
With ABS, you will be able to
正常的控制车辆行驶方向
steer the vehicle properly
而且还能缩短刹车的距离
and it also reduces the braking distance.
什么是ABS呢?
What is ABS?
它是怎么防止由于
How is it able to prevent accidents
刹车而引起的车祸呢?
due to the braking?
我们将会在这个视频中探讨这些问题
We will explore these questions in this video.
为了正确的理解ABS
To properly understand ABS,
我们首先需要知道
we first need to understand the principles
转向和刹车的原理
of steering and braking.
当你踩下刹车踏板时
When you press the brake pedal,
轮台上的刹车片就会启动
the brake pads on the wheel desks will be activated
按压着轮盘
and press against the disks.
从而阻止车轮的转动
And this will stop the rotation of the wheels.
当车轮停止时
As the wheels stop,
路面和车轮之间会出现滑移产生摩擦
this causes slippage between the road and wheels
车就会在这种摩擦力的作用下停止
and the vehicle stops due to this friction.
现在 让我们了解一下转向装置
Now, let’s understand the steering mechanism.
整个的转向装置是建立在
The whole steering mechanism is dependent on
车轮滚动的简单原理上的
the simple principle of the wheels rolling.
车轮一直尽量
The wheels will always try to
避免在路面上发生滑动
avoid slipping on the road.
所以 这意味着在接触点上
So, this means that the velocity of the wheel at the contact point
车轮的速度一直是零
will always be zero.
车轮有两种运动
The wheels have two kinds of motion.
它们绕着轴线旋转
They rotate on their axis
也会朝着汽车行驶的方向移动
and also they move along the direction of the car.
由于这两种运动方式
Due to these two kinds of motion,
它们也有着两种速度
they have two kinds of velocity,
平移速度和旋转速度
translational and rotational.
为了达到防滑的条件
For non-slip rolling conditions,
车轮在接触点上的平移速度和旋转速度
the sum of the translational and rotational velocities
的总和应该是零
at the contact point, should be zero.
只要在脑子里记住这个简单的原理
Just keep this simple principle in mind.
你就能很轻松的
You will very easily be able to
理解转向装置了
understand the steering mechanism.
在汽车行驶过程中
In an automobile,
汽车的四个轮子会一直保持转动
all four wheels should be rolling
来避免汽车发生滑动
at all times to avoid the vehicle slipping.
实际上
In fact,
这个简单的转动原理就是
this simple rolling principle is the reason why
你只要移动前面两个车轮
your car turns
你的车子就能拐弯的原因了
when you turn the front wheels.
让我们模拟这样一个过程
Let’s examine this.
假定一个假设的条件
Assume a hypothetical condition in which
即使你转动了轮子
even after turning the wheels,
你的车子依然直行
the car carry straight on.
在这种情况下 转动速度
In this case, the rolling velocity
将会像这样转向
will be inclined as shown
直行的速度保持方向不变
and the translation velocity remains straight.
因此 如果你对这两种速度求和
Therefore if you add up these two velocities,
那么速度和将不会是零
the resultant velocity will not be zero.
这将会造成车子的滑行
This will cause the car to slip.
避免滑行的唯一办法就是
The only way to avoid this is
使直行的速度也同样改变方向
by making the translation velocity also inclined.
只有当整辆车像这样
This is possible only when the whole car
拐弯才有可能
makes a turn as shown.
当车子拐弯时
When the car makes a turn
所有四个车轮在每一时刻
at the instantaneous center shown,
都能满足滚动的条件
all four wheels can satisfy the condition of rolling.
从这个快照中
From this snapshot,
你能够清晰地看到在接触点上四个轮子
you can clearly see how the velocity at the contact point
的速度是怎么变成零的
of all four wheels becomes zero.
现在让我们来分析一下
Now let’s analyze the steering mechanism
刹车时的转向装置
at the time of braking.
由于刹车片已经启动
Due to the brake pads being activated,
轮胎会停止转动
the wheel stops spinning.
即使车轮拐弯了
Even though the wheels are turned,
因为它们并不旋转
since they are not rotating,
所以一点儿旋转速度也不会有
there will be no rotational velocity at all.
假若这样 汽车不需要转弯
In this case, the vehicle does not need to turn
因为这已经变成了一次普通的刹车
as this has become like a normal case of braking.
汽车将不再对司机作出的
The vehicle will no longer react to
转向指令作出反应
the drivers changes to the steering
而且会沿着一条直线滑行
and will slide in a straight line
而这会造成事故
which can cause an accident.
除了转向失去控制
Apart from losing control of the steering,
没有ABS的车还会面临另外一个大的问题
cars without ABS face another big issue-
——在不同光滑程度
braking on surfaces
的表面上刹车
with different levels of traction.
当左侧轮胎和右侧轮胎
When the left and right wheels are
处于不同光滑程度的表面上时
on different traction surfaces,
刹车时将在
applying the brakes will generate
车轮上产生不同的摩擦力
different frictional forces on the wheels.
这就会产生扭矩
This will produce torque.
车子会无法控制地旋转
And the car will go into an uncontrollable spin.
让我们来看ABS如何来解决这个问题
Let’s see how ABS solves these issues.
一个防抱死系统非常简单
An anti-lock braking system is very simple.
ABS可以防止
What ABS does is to prevent
车轮彻底锁死
the wheels from completely locking up.
ABS系统有速度传感器
The ABS system includes speed sensors
挨到车轮上
attached to all of the wheels.
当传感器发现
When the sensors detect that
一个轮子即将抱死
a wheel is about to lock up,
一个调整单元会
a modulator unit partially releases
给车轮释放一个制动垫
the brake pad on that wheel.
这样 车轮就可以
This way, the wheels will be allowed to
在刹车时间歇转动
spin intermittently during braking.
你就会立即看到
You can immediately see the effect of
车轮间歇转动的效果
this intermittent wheel rotation on steering.
车轮将有
Here, the wheels will have a rotational
转动速率原件
velocity component.
这样就能驾驶
This will definitely allow the steering to function
司机就能驾驶
and driver will be able to steer the vehicle
即使在刹车时
even during the braking.
问题是
But the big question here is
这个间歇动作释放制动
how does the action of intermittently
如何缩短了刹车距
releasing the brakes reduce the braking distance.
给这个问题一个答案
To get an answer to this question,
我们要理解
we first need to understand
轮胎和路之间的摩擦系数
how the coefficient of friction between the tire and the road
不同的滑动
varies with respect to slip.
在理想的滚动情况下
In perfect rolling conditions,
摩擦系数
the value of the frictional coefficient
接近零
is nearly zero.
然而 当车轮滑动时
However when the wheel is 100% slipping,
开始滑动摩擦
sliding friction comes into play.
你会看到滑动摩擦力
You can expect the frictional values for
各不相同
other levels of slippage to vary like this.
但橡胶是一个很复杂的材料
But since rubber is a complex material
制动时有很奇怪的表现
which has strange behaviors during braking.
车轮和路面之间的摩擦系数
The frictional coefficient between the tire and the road
不同
varies as shown.
滑动方面
With respect to slippage,
在12%的滑动比时
it has a peak value at
达到峰值
around 12% of slip ratio.
再高于或低于这个
And below and above this,
摩擦系数降低
the frictional coefficient reduces.
没有ABS制动时
During breaking without ABS,
摩擦系数
the frictional coefficient
起作用的
which comes into effect
主要是滑动摩擦
is predominantly sliding friction.
当ABS制动时
However, in ABS braking,
聪明的算法会调整制动压力
the clever algorithm adjusts the break pressure
保证滑动比率接近12%
to keep the slip ratio near to 12%
这样摩擦力最大
where the frictional value is at the maximum.
这样就明显降低制动距离
This significantly reduces the braking distance.
现在 回到汽车的不稳定性
Now, back to the huge instability issue of the cars.
凭借智能电子制动系统
By intelligent electronic braking distribution,
它是现代ABS的子系统
which is a subsystem of modern ABS,
就能轻松解决问题这些
one can overcome this issue very easily.
EBD
An EBD.
车的角速度
Yaw rate of the car and
以及车轮的相关滑动都有测量
the relative slip of each wheel is measured.
通过减轻制动压力
Just by reducing the brake pressure
车轮有更高的抓力
on the wheels with higher grip,
我们就可能降低
we will be able to reduce the frictional force
车轮的摩擦力
produced by these wheels.
就能保证横摆力矩
This will keep the yaw torque
车子得以控制
and the whole car under control.
我们希望这个视频带给你
We hope this video gave you
一个关于ABS
a clear conceptual overview of
工作原理的清晰解释
the workings of ABS.
别忘了
And please don’t forget to
通过Patreon支持我们的
support our educational activities
教育活动
on patreon.
谢谢
Thank you!

发表评论

译制信息
视频概述

ABS系统

听录译者

Felicity

翻译译者

Tiger_woo

审核员

审核员1024

视频来源

https://www.youtube.com/watch?v=98DXe3uKwfc

相关推荐