So, in other words, ClearMotion is producing a technology that other OEM's have been doing for years. Just off the top of my head, Cadillac has their magnetic suspension (which uses a fluid that changes viscosity in the presence of a magnetic field. I guess this is the same as what TFA claims is brand new.) The Ford Raptor with their live valve by Fox has a solenoid valve that regulates the shim pack. (Funny enough, I've spent all morning doing a FEA analysis of their valve.) The latest Mercedes Gelandewagen also has solenoid valves in their dampers to switch between soft and hard damping. Citroen has been doing it since the 50's with a purely mechanical system.
The basic idea is very simple: you want a computer to regulate the damper between soft and firm, as the road dictates. The implementation of this can become very complicated and there's a number of very different implementations. If I remember right, the Bose implementation required too much electricity to be practical. Most other implementations have some type of solenoid valve to control the pressure drop of the hydraulic fluid across an orifice. Again, the theory is simple, but mass producing a system that is cheap, reliable, yet can respond in milliseconds is difficult.
much like every luxury brand has tried at least once or twice in the past 30 years.
Consider it in the context of camera based self-driving cars, it's tangential to this discussion but it's an easy to visualize metaphor:
- A car traveling 60mph is traveling at 88 feet per second
- Assuming a 60hz camera, there would be a 16.67 ms gap between each frame
- The car is traveling 1.5 feet between each frame interval
- A certain amount of exposure time is necessary for the camera to generate even 1 frame or it will be blurry
- High framerate cameras often work around this by staggering/interlacing multiple sensors, but doing this implicitly increases the latency of each frame
- A 120hz camera might deliver double the frames per second, but each frame could be arriving 4 frames late in exchange
- 4 frames would be imperceptible to humans, it would be 3 feet for the car
- You haven't even processed any of these frames yet.
- Your off the shelf library introduces a random 1 second delay for some reason and costs you 88 miles in processing time
- The car can drive as fast as 120mph
All digital sensors implicitly have a sampling frequency, and the fundamental disconnect is always high sampling frequency =/= low latency. People constantly make this mistake over and over, and by the time you notice you are already too deep into development to make a change.
Decreasing latency is expensive, and requires specialized knowledge. Often you get expert software engineers who end up bottlenecked by the hardware limitations they can't even comprehend or the reverse, hardware guys bottlenecked by the software they can't introspect. The latency is only truly understood when you get to integration testing.
Nearly every step of the way you discover you need specialized hardware, software, operating systems, sensors. Every part of the chain each costing you more latency. It's like it's own ecosystem where almost everyone writes everything from scratch and doesn't share anything. It's gotten better in recent years though.
Full disclosure: I work in medtech and don't actually deal with cars, but it's a very similar problem space. We often use the same hardware/software cars use for this reason.
In regards to the 120hz camera line, I would be happy to expand on that for you. To be clear, I'm specifically talking about how when you try to increase sampling rate by interlacing multiple concurrent digital sensors you need to deal with the following potential problems (this is a property of all digital sensors):
- Real time synchronization between concurrent sensors requires additional processing time to ensure proper ordering. The samples need to be processed together in small batches. This adds latency and the more things you are trying to synchronize the more latency is introduced.
- Inter-sensor calibration to account for variations between individual sensors can be used to reduce the latency introduced by synchronization but lacking this, you are bottlenecked by the slowest sensor. There are a lot of different ways to handle this though so I'm speaking very generally.
- Broadly speaking most signals need to go through some kind of filter to remove noise, most digital filters have a certain amount of algorithmic latency built-in that is physically unavoidable. When you are interlacing multiple different sensors, you are getting more noise, so the likelihood of a filter being required starts to increase.
I want to stress here that these are not impossible challenges. In fact they are largely solved problems. But they are not universally solved in the same way, you need to balance between precision manufacturing, signal quality and signal latency. In practice most people are not prioritizing latency, so a 120hz camera might be optimizing for video recordings and not live processing scenerios. So long as you know what you are looking for you can avoid this when choosing which camera to use.
Computers can be fast, but fast can mean different things when dealing with real-time situations in high speeds. Bottlenecks need to be considered from all levels. The clock speed of the computers CPU often gives product managers weird ideas about what is possible. This was the main point I was trying to make here.
> Assuming a 60hz camera, there would be a 16.67 ms gap between each frame. The car is traveling 1.5 feet between each frame interval.
Ok? So? You are just stating this as if we should understand the implications. I do in fact work with self-driving cars. What you say is true, but it is not a big deal. Why do you feel this maters? Or what is your point?
> A certain amount of exposure time is necessary for the camera to generate even 1 frame or it will be blurry
This is a confused statement. A certain amount of exposure is necessary for the camera to collect light. If you don’t have long enough exposure the picture will be dark, not blurry. Your statement makes it sound as if avoiding blur is why we need exposure time, which is a complete nonsense.
In reality none of this is a problem. There are automotive grade cameras which can collect enough light fast enough that the images are not blurry in practice. Yes, these cameras have a non-zero exposure time. Yes, this adds latency. No, this is not a problem.
> Your off the shelf library introduces a random 1 second delay for some reason and costs you 88 miles in processing time
You mean 88 feet. If my off the shelf library introduces a random 1 second delay i will chuck it in the bin post haste. Use stuff whose performance characteristics are well understood by you and is not terrible.
> Nearly every step of the way you discover you need specialized hardware, software, operating systems, sensors.
I do not recognise the world you describe.
Sorry not trying to dunk on you here, but this reads like something a junior engineer would complain to me about. These are not trivial problems, and I'm sure your co-workers who resolved them already so you didn't need to worry about them would agree with me.
> In reality none of this is a problem. There are automotive grade cameras which can collect enough light fast enough that the images are not blurry in practice. Yes, these cameras have a non-zero exposure time. Yes, this adds latency. No, this is not a problem.
You are contradicting yourself here, yes there are automotive grade cameras, but if this wasn't a problem, why would automotive grade cameras need to exist? My post wasn't saying these were impossible problems but hard ones.
> You mean 88 feet. If my off the shelf library introduces a random 1 second delay i will chuck it in the bin post haste. Use stuff whose performance characteristics are well understood by you and is not terrible.
Look I might have typed the wrong unit but it's a bit ironic you gave me this word salad right after complaining about this... Yeah you obviously don't use the library that adds a 1 second delay, but often you don't have the luxury of knowing that until after you learn about it through integration testing.
Libraries don't usually come with latency stats calibrated to your desired hardware right on the tin, would be pretty sweet if they did though.
> I do not recognise the world you describe.
I don't find this surprising :)
Tangent: why do so many people (even smart articulate ones like you) in our field (which involves precision with syntax and grammar) get apostrophes wrong?
"It's [IT IS] like its [ITS/HIS/HER/MY/YOUR/THEIR] own ecosystem..."
I anticipate downvotes for picking nits (let alone mentioning karma points), but FTR my intent is to help non-native English speakers (and mostly-literate English language-natives). Getting this "it's : its" distinction wrong is increasingly common and sometimes leads to signal loss.
Yesco, rereading your comment makes me slightly ashamed of this apostrophe rant, I hope others comment on the substance here. / end tangent
As someone who spent years doing web performance optimization for a living, your observations resonate. Beyond obvious low-hanging fruit, latency gains are rarely simple to achieve in practice; tradeoffs abound.
For a simple example, let's say you are simply driving in a circle. The car wants to lean toward the outside. The linear motors can provide a countering force, lifting the outside, lowering the inside, so the car stays level. Variable damping can only control the rate that it rolls. It will still roll in sub-second timescales, unless it completely locks down the suspension, which is terrible for both handling and comfort.
For another simple example: going over a speed bump. Linear motors can lift the front wheels over the bump, and then the rear wheels, so the body stays level the whole time. An active damper can go full-soft the moment the wheel hits the bump, but the compressed spring will still start lifting the front of the car. An active damper can do a better job managing the rebound on the far side so it doesn't oscillate, but it can't entirely prevent the bump from pitching the body up and down in the first place.
That's not to say it's worthless. Very fast active dampers can improve both handling and comfort. It's just nowhere near the level which is possible with linear motors.
I remember watching Citroens demonstrating losing a wheel, and continuing to drive, in the early 1970s.
Citroens are cool. Maybe their build quality wasn't so good, or they were too expensive, as I've not seen them on this side of the pond.
Their build quality is fine, at least contemporarily to the rest of the market; of course today, we would find its steel pitiful. It's not without reason that people who maintain Citroëns of that era tend to replace the panels with fibreglass ones.
Additionally, as Citroën pulled out, the maintenance network in North America began to falter, as the suspension system required significant know-how. There are still a dedicated group of Citroën fans in North America (albeit small), and I met a lot of them when I drove from coast to coast (and back again) back in 2017 in a 1998 Citroën Xantia. A car that may not seem particularly interesting to Europeans (although it was the Activa V6 model), but it was extremely rare in North America.
"It is noteworthy that the previous record holder (set in 1999) was the Citroën Xantia 3.0i V6 Activa, an unassuming family car with a unique active roll bar system.[15]"
(active ride begins at half the vid, at 1:17):
Or look the slalom at about one minute in the vid. That's not 3D.
Why would we be interested in the technology from 1980s… oh.
Also, this is Bose of active noise cancellation - very fitting, since this looks like anc for wheels. They did anc for car seats too and sold it to the same buyer:
> As part of the deal, ClearMotion also acquired the technology for Bose Ride, a special "active" car seat for truckers that improves ride quality and reduces occupant fatigue. Bose used what it had learned from developing the active car suspension system to create Bose Ride, but it remains a niche product.
https://www.cnet.com/roadshow/news/bose-sells-its-futuristic...
I was wondering why the heck Bose got into this. Thanks, that was the missing link -- I never thought of suspensions as noise cancellation but of course they are!
It seems as if speed bumps are a rather questionable approach to traffic calming, as larger vehicles (which should be a priority for calming) are less affected.
similar to a race car -- you don't compensate the speed with damping and spring rates in order to maximize a smooth ride , you do it to more quickly transfer the movement energy OUT of your car, into the ground and traction patch so that the car can remain dynamic for the next force.
this does not equate to ride quality, most race cars (and bikes) are bone-shakers.
high performance cars are mostly bone shakers at slow speeds when not in their ideal operating range. at high speeds they should level on top of it all, just watch a rally truck go over dunes or the video of an F1 wheel well stabilized to the frame of the car. sure you have low-frequency high-g-force weight transfer during acceleration/deceleration, and you have high frequency signal from the road texture, but medium frequency parking-lot-speedbump-style bouncing should not be happening at all or you're going to lose the race.
That’s the point. They’re not supposed to damage the car. They’re supposed to be a little uncomfortable if you’re going too fast.
It’s more reminder than a physical stopper.
> In fact the faster you hit them or the more load you're carrying the better the suspension handles it because you open up the high speed compression valves.
This is a case of knowing just enough about a topic to be dangerous.
Entering the higher shaft velocity part of the damper curve doesn’t mean the suspension is handling it “better”. The high speed behavior of the valving simply means the damping forces aren’t increasing linearly with shaft velocity. They trade extra travel for reduced peak forces.
Make no mistake, though. The faster you go, the higher the forces. The high speed valving (if the OEM dampers are even digressive) isn’t changing that.
If the speed bump is tall enough and the bump stops get completely compressed you could bottom out the damper, which is not good for it.
> I'll often hit them at 30mph+ with no issue.
Just because nothing immediately breaks doesn’t mean you’re reducing the life of the OEM dampers. Repeated high speed impacts and will shorten the life. Getting the wheels bumped up into the range where you’re compressed bump stops transfers a lot of energy into the bushings and other components.
> Rolling over them at a slower speed where your shocks stay uncompressed forces your whole car to go up and then down again, instead of absorbing the energy in the shocks.
That’s the ideal way to do it. This is better than the sudden sharp impact of high speed crossing. You’re not doing your car any favors by driving quickly over speed bumps. Fortunately for you, OEM replacement dampers aren’t too expensive but replacing prematurely worn bushings is kind of a pain.
That's not just adjustable damping; that's a fully powered suspension.
Both this and the Bose linear actuator one lift just the wheel that needs lifting, just enough to clear the obstacle, keeping everything perfectly steady, it's incredible.
The fact that it can also do silly jumps for marketing reasons is a different topic.
Surely the system takes cornering into account. Having a suspension that can use predictive motions to compensate for a pothole would ideally produce better handling by minimizing the disruption of a pothole imparting a massive disturbance to the vehicle.
> It can sense and jump potholes.
The Bose system’s most famous demo was sensing and jumping over speed bumps.
> That's not just adjustable damping; that's a fully powered suspension.
Right, but it appears the company who bought the Bose Magic Carpet portfolio isn’t doing what the original demo did 20 years ago, they’re just using the name.
That system uses hydraulic rams in series with the usual suspension springs and dampers, and can handle up to 5 Hz (i.e. it controls the lower frequency part of the spectrum so softer springs etc can be used, improving both ride and handling)
The most comfortable car I’ve ridden in suspension wise was a Mercedes SUV. So maybe they figured that out already.
(I used to live in a neighborhood full of them and I liked them but very many people disagreed with me. If you make speed bumps not work then they will all be replaced with slaloms or circles.
Is there any serious argument against them? I've heard they aren't common in America.
They were rare in the US before, I want to say, 15 or 20 years ago but I see them all the time now and new ones are always being installed. Good traffic devices, with the above tradeoffs in mind.
Where roundabouts get bad is when they’re multi-lane and can get a lot of traffic. There’s one I se fairly regularly and I’m surprised there aren’t more accidents.
As a result, I hated them until years later, when I encountered one that was done correctly. After that, I completely flipped my opinion. Done right, they can completely beat a traffic light for wait time and throughput.
They are in the Northeast. But they don't always keep bad drivers away.
For America specifically: they're not a great fit for places where everything is spread out and the road system is sensibly designed. I can drive from one side of Tulsa to the other (on streets, not freeways) in a fraction of the time I could drive across a similarly-sized European city. That's because the city itself is designed for cars. It has straight major streets with 40-45 mph speed limits that form a grid. Neighborhoods sit inside the grid and the streets in them curve with the landscape. In most of the city you have maybe 3-5 traffic lights per mile on the major streets, so unless it's rush hour you get minimal slowdowns. Sometimes I can drive several miles without hitting a red light.
The ideal situation is to have a straight road with no traffic directly between you and where you want to go. Obviously, that's not possible. So you have to compromise. Roundabouts suck, but they're better than almost any other option in places that have twisty narrow streets and lots of pedestrians. Many (most?) American cities aren't like that (at least to the extent European cities are), so roundabouts don't make as much sense here.
They're getting more popular in the Puget Sound area. We have been re-engineering streets to include roundabouts all over the place. I think they're a great thing, but too many people still stop at the wrong time.
IRL this is probably just handles small bumps and turns comfortably thing.
Are there traffic circles that are primarily about slowing traffic rather than managing intersections?
If you don't mind old cars you could explore the rest of the lineup that touched the 1UZ/2UZ motor/3UZ; they're all pretty good. SC430,GS430,GS400,LS430,LS400. [0]
As far as modern Toyota goes.. I couldn't make a recommendation. I like the newer Prius, but it's a different market and I wouldnt vouch for the reliability, although i've had good luck.
franktankbank•3d ago
genter•8h ago
smackeyacky•8h ago
Some crazy, unfixable magnetic suspension that lasts 3 years and requires $5000 a corner shocks is par for the course these days.
thrill•7h ago
throaway920181•7h ago
Well, you can take money out of an ATM machine to pay for that. Just try to remember your PIN number.
userbinator•6h ago
Smallblock Chevys have a timing chain at the front but it's basically never a failure point. I agree with your other points, however; the trend is to optimise for short-term efficiency and cost, resulting in complex and relatively fragile designs.
brookst•4h ago
jibe•5h ago
make3•6h ago
It would be so easy to just code up the perfect reaction in advance, & it not be representative at all of the conditions in the streets where the machine actually has to detect and respond dynamically to the conditions of the road