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Ackerman Steering - Explained
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- čas přidán 17. 04. 2012
- What is the Ackerman principle and what does it mean in terms of how it affects my car and steering? Ackerman steering ensures that all four tires have a common point around which they rotate when the car is turning. This ensures that none of the tires are required to slip in order to complete a turn.
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All i could think of was "How an Ackermann steers the ODM gear to slice up titans"
I have also seen other videos regarding Ackerman steering geometry, but trust me I had never understood it so smoothly as this one. Sir, you are a genius teacher.
Thanks! Very god explanation. I bought AWD and salesman could not explained how it work. You are brilliant teacher and explained it very well!!!!
Working on a project for school (go NC State!) and needed an overview of the Ackerman model. CZcams brought me here and it's crazy seeing how your production has changed in 8 years
I'd like to thanks you alot, you learned me more in 3 minutes, than my tearcher in 4 hours.
Zellu le Lampadaire learn some English lol
Sure, if you go to the FAQs on my website (link in the description) I have a list of recommended books. The fourth book I have on this page "Automotive Engineering Fundamentals" discusses Ackerman steering. Though there is probably a cheaper reference out there (which I do not currently know of).
I'm not sure what the best way to go is, but it's certainly one way of doing it. I've written an article on my website with a bunch more info: howdoesacarwork(dot)com -> FAQs -> Future Plans.
Check out my AWD video I give a basic explanation of viscous couplings within that. Glad you enjoy the videos!
i see Ackerman I click and watch
hi antie🌚🥂🌝
@@Hutao-go2sh oh hello dear 💕
@@wypy817 ❤️❤️
Hahaha same
AOT?
You helped me with my car set-up in assoluto racing
Thy engineerening explained from the past :)
Me too
I just started as a quality engineer. Thanks for the quick run down of why differentials are needed
A differential allows for you to have varying speeds between the left and right wheels, or front and back wheels. Ackerman steering says that the left and right wheels will rotate at varying speeds.
Hmm, I've got a book "Automotive Engineering Fundamentals" by Richard Stone and Jeffrey Ball, but it doesn't have too much on steering design. It does go into some detail on design as far as understeer/oversteer, and the caster/camber/toe/etc..., but it's more of a general overlook. Wish I could be of more help. My best advice would be to search forums and see how this has been done by others, and what success people have had with certain setups. Good luck to you!
Cool video... I always noticed on cars that the inside tire always seemed turned out farther than the outside tire... now it all makes sense. Keep up the good work!
High speed stability. Forklifts are rear steering as it helps in tight spaces, but at high speeds you'll spin around very easily with rear steering.
You're welcome! Thanks for the kind words! Share with you're friends and maybe I'll hit that target haha
2020 still the best explanation
2021 still the best explanation
Thanks for teaching and sharing, on such a young age. We need more of that, because telling your knowledge to other people makes getting smarter so much faster! If we all do it, we can become much smarter in one life time. Spread the word!
sinc., a college student.
Race cars are typically rear wheel drive, and thus do not require a front differential.
00:00
hey everyone
00:02
in this video I'm going to be going over the Ackerman principle or Ackerman steering
00:06
now I want to go into this because I'm going to start going into four-wheel drive
00:10
and all wheel drive
00:12
and it's an important principle to understand
00:14
before I go into those
00:15
the name Ackerman comes from a guy named Rudolph Ackerman
00:19
who actually was the guy who patented this idea
00:23
the problem was it wasn't his idea of the there was a German inventor that came to him
00:28
he was a lawyer Rudolph Ackerman
00:30
and so he patented the idea
00:32
but somehow his name got placed on it
00:34
I'm sure he did that
00:35
but so it's not really his idea
00:39
but anyways he's got the name
00:40
what's happening here
00:42
so now back before the acronym steering was around
00:47
some of the tires would slip
00:49
because they've come to a different point
00:50
so what Ackerman steering
00:51
the reason it exists
00:53
is that so your tires do not slip when you go around a corner
00:57
now how you achieve this
00:58
is by having a central point at which all your tires are rotating around
01:04
so you can see that the angle of this tire this inside left tire
01:08
is going to be greater than this outside right tire
01:13
so with that angle being greater
01:16
they can come to a central point and then all four tires can rotate around one point
01:22
which means the tires don't have to slip as they go around
01:25
if these two had the same angle then they'd have to slip around some uncommon point
01:30
and so that it wouldn't be it wouldn't work as well
01:34
especially at high speeds
01:35
so Ackermann principle is is great for for solving this problem
01:41
now one thing that you have to see when you look at this
01:44
is that look at each path each radius
01:47
so each tires path has a different radius
01:51
now what that means is
01:53
each tire is rotating at a different rate
01:56
so the one on the outside travels a further distance than one on the inside in the same amount of time
02:03
so it's rotating more quickly
02:05
so in in descending order the angular velocity of each tire goes from one to two to three to four
02:13
that's the descending order
02:14
so this is rotating the fastest and this is rotating the slowest
02:18
because it's got the smallest distance to travel
02:20
now
02:21
what does this mean
02:23
well this means your right side is moving faster than your left side when you go on the left hand turn
02:29
and vice versa if you go in the right hand turn
02:03
also what this means is that the front tires
02:35
because they're traveling a greater distance as you can see
02:38
then the rear tires
02:39
they are moving faster than the rear tires when you turn
02:44
so this is the real reason that you need a differential in four-wheel drive
02:48
if you're if you're in four wheel drive on a pavement or something like that
02:48
we have enough traction enough grip
02:48
then you're going to need a differential so that you can split the speeds between the front tires and the rear tires
03:05
otherwise you're going to have some buckling it's not going to work out
03:09
and you're going to have you're going to wear the tires
03:11
and you're going to be slipping you'll have understeer
03:13
so you want it so you have a differential
03:15
if you put in a center differential right there
03:18
then that would allow these tires to rotated a different rate than these tires
03:22
and then you put in a differential at the front and differential at the back
03:27
and that would allow each of these two tires to once again rotate it different rates
03:31
so this is important before I go into my four wheel drive and all wheel drive explanations
03:37
so I really hope this makes sense
03:38
and then I'll be going into these more complicated ideas of four wheel drive and all-wheel drive
dafuq
It has been shown in the video that all the wheels turn for a common center.
So, the angular velocities of all the wheels will be the same.
Their linear velocities would be varying. ( as the radius from the center varies)
The descending order discussed might be true for linear velocities, but not for angular velocities.
+Shashvat Mehta i guess he is talking about the angular velocity of rotation of wheels about their own axis which will be different for all wheels.
thank you very much for all these great vids!!! anytime I question something in the mechanics of , or I need a definition explained in visual I come here. Everytime. thank you. thank you. keep it up!
Correct, there are full-time and part-time 4WD, as well as AWD and automatic AWD. Different companies use many different names for each (it's a become a branding thing), however I will give definitions for what I will refer to each as, and how to differentiate between them.
I think that descending order that you mentioned is that of linear velocity rather than angular velocity. All the four tires will have the same angular velocity but different linear velocities.
yes you are right
I have been watching your videos it is helpful for synthesising FSAE car ...Thank you
Well I came here to learn about the Ackerman steering. It was mentioned but not explained. Principals were discussed but that was already known. How does the Ackerman steering achieves the higher angle on the inner wheel is my issue.
Yes, which is why they use open differentials, so speed can differ. Watch your average 2WD in snow, one tire will spin while the other remains motionless. This is due to the differential.
Dude im in 2020 worlds maybe going to end but your vids have helped me through my college course if you can reply it would make my day. Thank you.
No idea what all this is about - Ackerman steering and differential gearing were around long before the motor car. Horse drawn carriages had wheels that revolved independently of each other so scrubbing wasn't a problem. The reason Erasmus Darwin came up with the idea of Ackerman steering was because on one of his medical calls his carriage overturned and he suffered a broken leg. He was sitting outside of the triangle subtended by the front axle's central pivot and the rear wheel hubs when the axle turned through 90 degrees, his portly stature caused the carriage to fall over. Introducing kingpins and four point location (as opposed to three) made for stability. This is why this arrangement is used on motor cars. Differential gearing is used to solve the problem of wheels revolving at different speeds when cornering.
He never talked about when Ackerman steering and differential gearing was invented. This channel just happens to be in the context of cars.
corsair919 ackerman steering is used to account for differing angles needed for each wheel to travel through a corner without slipping. Differentials are used to account for the different rotational speeds each wheel needs as it goes through the corner.
The reason why this steering method is so effective is because it has titan powers
Sheesh
We've came a long way since this video, huh Jason. 🤣 To be fair this is still a better explanation to me than most videos on this topic.
Great explanation! i think ive watch 80% of you videos in 24 hrs lol
Ackerman steering basically just shows you visually why there is a speed difference, and how car steering is set up for low speed cornering.
there are some but, electronically controlled mostly and the front wheels steer too, after a certain speed however the motor is turned off and the wheels lock into place, it's mostly to aid in parking and tight cornering.
Differentials have fixed gearing, yes, but each side can rotate at a different speed. Type in "how differentials work" there's a video with several million views that's very good at explaining it. With an open differential, if one tire is stuck, the other tire can still rotate. This is an extreme, but shows you that the speeds of each wheel can be different.
If i had a little mechanical design background, and wanted to pursue a career in say automotive design, would a mechanical engineering degree be the best way to go? I am a drafter/designer in civil engineering. I am planing on going back to school to complete an engineering degree, and would prefer to do mechanical to civil. I love it!
As an engineering student and car nut, I have to say THANK YOU.
Wow! I watch all your videos and just watched this one from ten years ago
Thank you for making these videos! Loved to get the F1 radiator explained, but in this one did you not skip the actual explanation of the mechanics? I mean shure wheels go around at different speeds, but how to achieve the different turning angles for the inner and outer front wheel, mechanically some might ask.
I found it at Wikipedia though:-)
The front right moves faster than the back right. The back right moves faster than the front left. The front left moves faster than the rear left.
The front tires are moving quicker than their rear counterparts (of the same side).
I thought this video had to do something with Mikasa or Levi. Sorry, my bad!!
Cease to exist
KENNNYYY
Thank You so much for putting up this video. It really helped! :)
Some Chevy trucks have rear steering in addition to steering in the front. The angle of the rear wheels at full lock are of course smaller than in the front.
Oh my God, Jason was so Young!!!!!!!!!!!!!!!!!
yes there are;i'm looking forward to the videos.i know i'll know all or close to all of it but..interesting though,i reasearch stuff i already know alot out of interest...well yeah there are a few ways/systems of driving all wheels,a guy i kinda knows through my father has a truck i think if i heard right has RWD, 4WD and automatic modes..i know some trucks came with full time AWD with a locking center differential for off road etc i guess-so many layouts/systems.keep up the great videos. peace.
I like how you subtly talked about the STI DCCD without explicitly mentioning it
Wonderful teacher .which sterring gear is smoothest amd requires least effort. Worm and roller with variable steering ratio with hour glass primciple or the worm amd roller
There are. They have slight rear input, only a few degrees. If i remember the MX6 had it, among others.
Can you make new video on pro Ackerman geometry and what it is also how to find Steering arm angle and Steering arm length
Ooh is Ackerman principle also apply on the operations of the differential system
Wow, simplemente me fascino la manera en la cual lo explicaste, un buen like para ti buen hombre
Monster trucks have rear steering and there was a honda prelude that had rear steering at low speeds only that lasted for a few years in the 1980's
well explained man! heres something i never even heard of despite my great interest and knowledge of vehicles... probably cause i'm more interested in models and history and major internal mechanics...heres on thing i did know though: just to make the point; real 4 wheel drive does not generally have a differential; its referring to a part time system engaged for bad weather or off road, however all wheel drive would have a differential as it's a full time system used on dry roads... thanks :)
Around 3:22. You said if the front has a differential, it can make the front tires spin at a different speed than the rear tires. A differential has fixed gears in it...meaning, it can't switch gears like a transmission.
Does this mean that with AWD vehicles, the front tires are moving at a different speed than the rear tires full-time?
How does the differential know when to speed up one side when turning?
Hi on short track asphalt circle racing. Is it anti Ackerman or Ackerman you should be aiming for. I believe it to be Ackerman!
Yes, one tire would slip. However it's unlikely that any relatively modern car not have a front differential, it's pretty standard.
Correction:
The inner tires, with respect to its turning direction, should be the one that turns faster than the outer tires based on their angular velocities with time as constant.
The front left tire has a wider angle than the front right one. Thus, it will turn faster using this given formula:
Angular velocity = position angle/ time
Don't think that's quite right. The formula for angular velocity isn't equal to "position angle/ time" but the "change in angle /time". If we take your formula and apply it to the rear tires, then they would both be travelling at the same speed, which we know isn't the case because the outside tire travels a longer distance around a curve.
But doesn’t the right side move slower than the left still? Since the turn radius is larger than the left side as he mentioned earlier on in the video? Or maybe I still don’t get it?
But how is this going to help me kill titans? =)))
Good to revive a old topic but thanks for your video now I understand how AMG 4matics are good for nurburgring but sucks at low speed turns. Can you explain a bit more on its negative effect for example causing Tyre crabbing or juddering at low speed turns in cold weather? Merc owners are so angry about their expensive car making embarrassing turning noise around town.
This has everything to do with tire slip angle and what kind of corner you're driving through.
Bad steering setup can cause crabbing, but it isn't the only reason why a car might do that and isn't the main one. Plenty of things on cars can be set up wrong, especially after people have tried to "tune" their suspension with coilovers without having any idea what they're doing. This is way more often the cause of crabbing, where it's not actually steering related but instead is caused by people putting random aftermarket springs and shocks in cars "because it feels sporty." Additionally, OEM suspensions are usually designed with intentional suspension "problems," to keep people from killing themselves. The average car enthusiast isn't a proficient race driver at all - but thinks he is - and has no idea how to handle an actual race car. Very often, "sporty" cars will be designed to have serious understeer when turning and braking to keep the car pointed in the right direction. Everyone expects oversteer when flooring the gas, but not many people know how to handle oversteer when they touched the brakes or lifted off the throttle at the wrong moment. Porsche and Lotus have notorious examples of cars like this. People think they're dangerous and hard to drive. They're not, they just have a much more neutral design and it's easier to get the car to off-throttle oversteer where drivers have only ever experienced on-throttle oversteer.
On to ackerman. Keep in mind that tires generate force on the ground by warping. You have to warp the tire enough to create the force you want on the ground. With steering, this warping is slip angle. If one of your tires doesn't have enough slip angle, the tire on the other side of the car is going to get overloaded and let go.
The amount of pro- or anti-ackerman in the steering has to be set up for which type of corner the car is going to be going through, and also what kind of tire is being used. A lot of pro-ackerman (the tires turn in more than the theoretical ideal) will give a car better cornering in tight corners where you need to develop more slip angle on the inside tire, at already extreme steering angles. Anti-ackerman will help when you are trying to go through higher speed corners where the isn't much steering angle, but you need to develop slip angle on the outer tire anyway to get both tires to stick at the same time.
A side problem is the tires themselves. For a given sideways load (cornering), different tires are going to need to warp different amounts to generate peak grip. Race tires tend to slip less than road tires by 2-3 degrees. This is a huge difference; with things like ackerman, we're already talking single-digit changes in steering angle. A car set up with road tires in mind might not do so well on race tires, and vice versa. The suspension of a car is, in very large part, set up for the type of tire it's going to be running. Change the tire, and the ideal suspension and steering geometry is going to change. If a road car is designed to get the best performance possible on your average all-season, consumer-reports-approved tire, it's not going to get anywhere close to the actual limit of grip on a race tire. And vice versa.
Thank you!
awesome video man never thought of something like this before you made a video thanks for teaching me something new everyday
Hi Engineering Explained , I notice that front wheel axes cross at the center of the circle of the curve, that means they are not parallel. I mean, not only do they spin at different angular speed, but also they steer at different angles. Is it really that way?
Thanks very much for your time, I recently started to watch your videos and you are the best at explaining, it's all very clear, interesting and useful. Thanks a lot.
Hey, I'm not EE but i think I can answer your question. Yes, the front tires are steered at different angles. The steering linkages are set up in such a way that allows the two wheels to be at the required angle no matter what the actual position of the steering wheel inside the car is.
If you search for videos on the "Ackerman angle" or "Ackerman principle" you should find some videos showing the actual set up.
Dinsdale Drummond Thank you, now I'm searching by that name.
This is such a weird coincidence because Tony from UncleTony'sGarage mentioned the ackerman geometry for a build in which he shortened a frame.
Dude, awesome channel! Great videos for car geeks like me :)
p.s. any chance of a video on viscous coupling?
Hey jason!
Can you make a video on Front Steer vs Rear steer,
what should be the Ackerman percentage for off-road cars?
As an equivalent, I shall say you're welcome!
Sir your videos are very helpful
Actually, can you please make video on turning radius calculation according to the fsae skidpad.
I like your explanations. Would really like to see one on Bump Steer. Perhaps sometime you could do one on that subject!
bump steering is when you bump the steering wheel with your knees so you can text while driving
Could you discuss the physics of oversteer and understeer? It'd be great if you could! Thanks :D
Wow, that's awesome. What was it on?
Hi Jason, I really hope you get this. I'm doing an undergrad design project on a 4x4 drivetrain. So far your videos have been helping. I'm struggling to find literature. Can you recommend any sources: reviews, forums, papers etc. ?
Question: Why do sports cars have terrible turning radiuses (Raidia?) ? Is it only because of the handling? That you want a stiffer, more stable, suspension?
Video request!!! Please explain how Ackerman is achieved on front steer linkage. Aka the rack or linkage is in front of the front axle. My truck, Chevy A-body’s, and corvairs all have front steering linkage and nobody can explain how it keeps the correct Ackerman angle
I can not find this information anywhere and it’s making me mad. I know the outer tie rod ends are not outside of the steering axis but my inner wheel still turns more than the outer
Maybe I mean dynamic tow and not Ackerman
wow I'm watching him in 2018, he aged quite fast in 6 years ! :)
20% older so, haha
well explained man..keep up the good work..
what will happen if the instantaneous center of the front steered wheels lies behind the rear wheel axis? does it lead to oversteering or understeering?
This would be a good video to remake, I'm sure a lot more information can be added. Good video nonetheless.
I am watching all your videos. and i make a short notes from your
lessons.
as far as controlling ackermann and bump steer does a rack and pinion setup or a bellcrank setup offer better control and handling?
Idol, could you do a video regarding the principle of DRIFTING? Really appreciate it. Looking forward and thanks :D
Love these explanations! ...but shouldn't the green paths of the rear wheels be concentric to the fronts if they all share a common origin? 4 appears to cross 3, and 2 crosses 1
Excellent channel . I hope you do one on Davies steering system .
Thank your for the explanation! Very clear and easy.
Damn man I’m tryna learn this early before I do it in college and that but it’s so confusing lol
Great topic. Eventually I'll get there haha
+engineeringexplained: if front is moving faster than rear than how can ang. velocity intermix them as 1,2,3,4 ? This implies that right moves faster than left which is correct. If Front moved faster than back should it be 1,3,2,4?
It says on the white board that "Front moves faster than the back", yet it alwso says by the angular velocity descending that the front right and back right are spinning the fastest. I don't understand. Please Help!!
Thankyou, so what I need is to add the middle differential to my model, to split the speed between front and rear tires.
So if your front right tire treads are lower then left you make more left turn? , That’s my understanding. The dealership didn’t rotate my tires when I got a oil change and the front right tire treads were lower than other three, they said it wasn’t necessary so now I have to drive another 6000 miles and how it will probably be a hell of a lot lower. Were they just lazy, didn’t care or not informed?
Very well explained, thank you!
So... good or bad for drifting? If it can be considered one or the other.
Hello I have a problem of Ackerman steering in 3 Wheel . I hope you can help me .
How can we find the distance between point 3 and the point at the horizontal from the main intersection point.
Haha you had like the happiest face for the first few seconds.....
what about anti-ackerman steering used in formula 1 cars? the inside wheel turns less in a corner for no good reason i can think of
hey ackerman steering have all cars or just the 4wd?and what if you convert a rwd to 4wd?
Can anyone explain, if he says front wheels move faster than rear wheels as you turn, shouldnt it be 1 and 2 at front wheels in terms of velocity?
Working on designing the steering for an off-road baja vehicle. Any recommendations on books/videos/help?
Thanks!
Listen man, I'm gonna be honest, This video does explain how the idea of making this steering came in mind of people. But, it would be better, if the video explained the mechanism of the steering.
Next topic Ackerman titan experiments
damn precise and upto the point