Audi predictive suspension (AI) vs air suspension
09-23-2018, 05:11 PM
#1
AudiWorld Super User
Thread Starter
Audi predictive suspension (AI) vs air suspension
Some of you may be like me and waiting for Audi to release the Audi AI hydraulic based active suspension. When I first read about this feature, I was delighted because this would be one leg up over the S class because you can't get magic body control on 4matic models. I know that MBC is purely a hydraulic suspension system and is not riding on airmatic, and the two are separate systems. I have NEVER heard a case of the hydraulic suspension being inferior to airmatic because no journalist has brought it up. On the Audi system, I thought it was going to be a combination of Air Suspension + Hydraulic rams/system and they would work together.
I'm really sorry folks but I read an article this morning from a journalist who commented that it isn't the case and the Audi AI system would be hydraulic only like the MB, and it wasn't a finished product yet which is why we can't buy it. He commented that the Audi AI hydraulic system was much more fidgety than the air suspension. To Audi's point though it's not a finished product. I'm sorry here because I forgot to copy and paste the link and I can't find the article now.
So that said would I choose a fully air based suspension that gives me comfort all the time, or a hydraulic system that gives me the ability to skip over speed bumps and (to Audi's credit) be able to absorb potholes much easier (the MB system does NOT deal with potholes, only speed bumps), well in that case maybe I will decline the Audi AI option when it comes for, maybe 2020.
If anyone knows more about this system, please let me know. The manual talks about Audi AI suspension but doesn't elaborate, probably because the fellow responsible for this system clearly missed the timeline.
I know hydraulic based suspensions can be very well done. In fact I have to give Genesis G90 credit here. The suspension there is hydraulic only too, and while not as nice as an S class, it was VERY very close. That said, I still want my air ride I guess.
I'm really sorry folks but I read an article this morning from a journalist who commented that it isn't the case and the Audi AI system would be hydraulic only like the MB, and it wasn't a finished product yet which is why we can't buy it. He commented that the Audi AI hydraulic system was much more fidgety than the air suspension. To Audi's point though it's not a finished product. I'm sorry here because I forgot to copy and paste the link and I can't find the article now.
So that said would I choose a fully air based suspension that gives me comfort all the time, or a hydraulic system that gives me the ability to skip over speed bumps and (to Audi's credit) be able to absorb potholes much easier (the MB system does NOT deal with potholes, only speed bumps), well in that case maybe I will decline the Audi AI option when it comes for, maybe 2020.
If anyone knows more about this system, please let me know. The manual talks about Audi AI suspension but doesn't elaborate, probably because the fellow responsible for this system clearly missed the timeline.
I know hydraulic based suspensions can be very well done. In fact I have to give Genesis G90 credit here. The suspension there is hydraulic only too, and while not as nice as an S class, it was VERY very close. That said, I still want my air ride I guess.
09-29-2018, 03:46 AM
#3
AudiWorld Super User
Thread Starter
09-29-2018, 04:18 AM
#4
AudiWorld Super User
Car & Driver road test of A8 active suspension— Is it hydraulic, or more mechanical??? From the review:
Full Control
Although the A8’s new chassis is good—there’s ample body control and isolation with the car’s standard air springs and adjustable dampers—the active-suspension models we drove weren’t yet fully baked. The optional Audi Intelligence (AI) active suspension, one component of a suite of intelligent features, includes an electric motor at each corner capable of raising or lowering that wheel via a torsion bar linked to the suspension. In effect, there are two springs on each wheel of A8s equipped with the active suspension: an air spring and a torsion bar coupling the wheel carrier to the electric motor. The motors and torsion bars eliminate the need for traditional anti-roll bars by enabling roll control as well as managing pitch and dive.
The active setup’s most promising feature, however, is the ability to float the A8’s body over road irregularities. The AI system scans the road ahead with a forward-looking camera (Audi calls the function Preview) and turns that data into wheel motions that follow the road’s shape. Before the front wheels encounter an elevated bump, the body is raised to provide the additional suspension travel needed to absorb the imperfection. Then, as the car passes over, the suspension is extended to trace the road’s topography. Dips and single-wheel events are handled similarly, with the wheels following the terrain while the body remains isolated. The system provides 2.0 inches of lift and 2.4 inches of drop at each wheel, enough to make speed bumps and manhole covers virtually irrelevant. Closed-course demonstrations of the Preview technology were convincing, but we didn’t get to experience it on the open road. Even though the active suspension was fitted to two test cars and performed as promised to limit roll, pitch, and dive, the Preview function wasn’t enabled on those cars. Audi’s Drive Select system is standard and offers three driving modes (Auto, Comfort, and Dynamic) and also integrates control of the AI suspension on cars so equipped.
Full Control
Although the A8’s new chassis is good—there’s ample body control and isolation with the car’s standard air springs and adjustable dampers—the active-suspension models we drove weren’t yet fully baked. The optional Audi Intelligence (AI) active suspension, one component of a suite of intelligent features, includes an electric motor at each corner capable of raising or lowering that wheel via a torsion bar linked to the suspension. In effect, there are two springs on each wheel of A8s equipped with the active suspension: an air spring and a torsion bar coupling the wheel carrier to the electric motor. The motors and torsion bars eliminate the need for traditional anti-roll bars by enabling roll control as well as managing pitch and dive.
The active setup’s most promising feature, however, is the ability to float the A8’s body over road irregularities. The AI system scans the road ahead with a forward-looking camera (Audi calls the function Preview) and turns that data into wheel motions that follow the road’s shape. Before the front wheels encounter an elevated bump, the body is raised to provide the additional suspension travel needed to absorb the imperfection. Then, as the car passes over, the suspension is extended to trace the road’s topography. Dips and single-wheel events are handled similarly, with the wheels following the terrain while the body remains isolated. The system provides 2.0 inches of lift and 2.4 inches of drop at each wheel, enough to make speed bumps and manhole covers virtually irrelevant. Closed-course demonstrations of the Preview technology were convincing, but we didn’t get to experience it on the open road. Even though the active suspension was fitted to two test cars and performed as promised to limit roll, pitch, and dive, the Preview function wasn’t enabled on those cars. Audi’s Drive Select system is standard and offers three driving modes (Auto, Comfort, and Dynamic) and also integrates control of the AI suspension on cars so equipped.
09-29-2018, 04:57 AM
#5
AudiWorld Super User
Thread Starter
Car & Driver road test of A8 active suspension— Is it hydraulic, or more mechanical??? From the review:
Full Control
Although the A8’s new chassis is good—there’s ample body control and isolation with the car’s standard air springs and adjustable dampers—the active-suspension models we drove weren’t yet fully baked. The optional Audi Intelligence (AI) active suspension, one component of a suite of intelligent features, includes an electric motor at each corner capable of raising or lowering that wheel via a torsion bar linked to the suspension. In effect, there are two springs on each wheel of A8s equipped with the active suspension: an air spring and a torsion bar coupling the wheel carrier to the electric motor. The motors and torsion bars eliminate the need for traditional anti-roll bars by enabling roll control as well as managing pitch and dive.
The active setup’s most promising feature, however, is the ability to float the A8’s body over road irregularities. The AI system scans the road ahead with a forward-looking camera (Audi calls the function Preview) and turns that data into wheel motions that follow the road’s shape. Before the front wheels encounter an elevated bump, the body is raised to provide the additional suspension travel needed to absorb the imperfection. Then, as the car passes over, the suspension is extended to trace the road’s topography. Dips and single-wheel events are handled similarly, with the wheels following the terrain while the body remains isolated. The system provides 2.0 inches of lift and 2.4 inches of drop at each wheel, enough to make speed bumps and manhole covers virtually irrelevant. Closed-course demonstrations of the Preview technology were convincing, but we didn’t get to experience it on the open road. Even though the active suspension was fitted to two test cars and performed as promised to limit roll, pitch, and dive, the Preview function wasn’t enabled on those cars. Audi’s Drive Select system is standard and offers three driving modes (Auto, Comfort, and Dynamic) and also integrates control of the AI suspension on cars so equipped.
Full Control
Although the A8’s new chassis is good—there’s ample body control and isolation with the car’s standard air springs and adjustable dampers—the active-suspension models we drove weren’t yet fully baked. The optional Audi Intelligence (AI) active suspension, one component of a suite of intelligent features, includes an electric motor at each corner capable of raising or lowering that wheel via a torsion bar linked to the suspension. In effect, there are two springs on each wheel of A8s equipped with the active suspension: an air spring and a torsion bar coupling the wheel carrier to the electric motor. The motors and torsion bars eliminate the need for traditional anti-roll bars by enabling roll control as well as managing pitch and dive.
The active setup’s most promising feature, however, is the ability to float the A8’s body over road irregularities. The AI system scans the road ahead with a forward-looking camera (Audi calls the function Preview) and turns that data into wheel motions that follow the road’s shape. Before the front wheels encounter an elevated bump, the body is raised to provide the additional suspension travel needed to absorb the imperfection. Then, as the car passes over, the suspension is extended to trace the road’s topography. Dips and single-wheel events are handled similarly, with the wheels following the terrain while the body remains isolated. The system provides 2.0 inches of lift and 2.4 inches of drop at each wheel, enough to make speed bumps and manhole covers virtually irrelevant. Closed-course demonstrations of the Preview technology were convincing, but we didn’t get to experience it on the open road. Even though the active suspension was fitted to two test cars and performed as promised to limit roll, pitch, and dive, the Preview function wasn’t enabled on those cars. Audi’s Drive Select system is standard and offers three driving modes (Auto, Comfort, and Dynamic) and also integrates control of the AI suspension on cars so equipped.
Then, one thing led to another and I was reminded that on the W222 S class, it's "either" "or". Magic Body Control is a 100% hydraulic system, and the regular suspension is a 100% air suspension.
Perhaps Audi has truly innovated, and only time will tell because some German engineer missed the deadline on AI. They have not let ANY journalist to test the system freely and on an open course. All demonstrates of this testing have been on a closed circuit course with ONLY speed bumps being used to show efficacy. No potholes (which Audi, unlike MB) has said that the system is meant to deal with that as well.
If I apply MB's system to Audi, I'm basically being forced to choose between AI (hydraulic I believe based on the above) or the standard air spring. I"ll choose the latter as that gives me a better ride 99.9% of the time.
But again, just my theory.
11-14-2019, 07:30 AM
#6
AudiWorld Super User
Thread Starter
Interesting. More details outlined in this S8 video about the new predictive suspension.
There's actually a few limitations that were not brought up in any previous literature. Most notably, the 'curve' or 'active' curve function ONLY works between 80km/hr and 130km/hr.
That basically defeats any purpose for me. On the highway, i'm at 149km/hr and in the city I'm between 0 and 70km/hr. $6000 option essentially just to smooth out the very rare speed bump?
There's actually a few limitations that were not brought up in any previous literature. Most notably, the 'curve' or 'active' curve function ONLY works between 80km/hr and 130km/hr.
That basically defeats any purpose for me. On the highway, i'm at 149km/hr and in the city I'm between 0 and 70km/hr. $6000 option essentially just to smooth out the very rare speed bump?
02-08-2020, 08:04 AM
#7
AudiWorld Super User
Thread Starter
As many of you know, I've been pretty fascinated with the predictive suspension and recently had a chance to speak with an Audi engineer who was involved in the design and implementation of the predictive suspension on the D5.
As we have discussed a few times, the predictive suspension does wonders over speed bumps, but it does not do anything to deal with potholes. The burning question I have had for a while is, why? I mean, if it can see depth, which it can, why can't it do the inverse of what happens in a speed bump? E.g., if a pothole is coming up, the wheel should be jammed downwards into the speed bump to try and keep the vehicle level. Well, now I know why.
The reason is traction. You see, Mercedes Benz has had magic body control for years, but only on the rear wheel drive S classes, and is not available on 4matics. Allegedly, the reason behind this specific design to not do anything re: potholes is a loss of traction. So say you're cruising along in the winter, as an example, the car then drives over a pothole and the active suspension does as I said earlier. The issue is that there's close to no grip for that wheel going into the pothole which causes a serious loss of traction from a drivetrain perspective. E.g. power is sent to the rear wheels, one wheel has no traction, and continues spinning. That wheel that does have traction (the one that isn't dealing with the pothole) doesn't get any power sent to it because there is no diff lock on these cars. This would cause the S class to potentially enter a hazardous driving scenario and break traction.
This is, however, a lot less of a concern with the D5 which has 4wd as everyone knows. However, Audi did still find problems when configuring the vehicle to actively deal with potholes. Namely, there were catastrophic cases of rims being bent as well as loss of traction and unpredictable vehicle dynamics in the winter as a result of this loss of traction that MB found themselves with as well. Due to driveability concerns, and thus safety concerns as well as a host of other issues configuring predictive suspension to deal with potholes, that ended up being a deal breaker for dealing with that specific scenario.
HTH!
As we have discussed a few times, the predictive suspension does wonders over speed bumps, but it does not do anything to deal with potholes. The burning question I have had for a while is, why? I mean, if it can see depth, which it can, why can't it do the inverse of what happens in a speed bump? E.g., if a pothole is coming up, the wheel should be jammed downwards into the speed bump to try and keep the vehicle level. Well, now I know why.
The reason is traction. You see, Mercedes Benz has had magic body control for years, but only on the rear wheel drive S classes, and is not available on 4matics. Allegedly, the reason behind this specific design to not do anything re: potholes is a loss of traction. So say you're cruising along in the winter, as an example, the car then drives over a pothole and the active suspension does as I said earlier. The issue is that there's close to no grip for that wheel going into the pothole which causes a serious loss of traction from a drivetrain perspective. E.g. power is sent to the rear wheels, one wheel has no traction, and continues spinning. That wheel that does have traction (the one that isn't dealing with the pothole) doesn't get any power sent to it because there is no diff lock on these cars. This would cause the S class to potentially enter a hazardous driving scenario and break traction.
This is, however, a lot less of a concern with the D5 which has 4wd as everyone knows. However, Audi did still find problems when configuring the vehicle to actively deal with potholes. Namely, there were catastrophic cases of rims being bent as well as loss of traction and unpredictable vehicle dynamics in the winter as a result of this loss of traction that MB found themselves with as well. Due to driveability concerns, and thus safety concerns as well as a host of other issues configuring predictive suspension to deal with potholes, that ended up being a deal breaker for dealing with that specific scenario.
HTH!
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gk1 (02-10-2020)
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02-08-2020, 01:35 PM
#8
AudiWorld Super User
Wait, so then this commercial was just 100% lies? Those sure look like potholes.....
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angrypengu (02-08-2020)
02-08-2020, 01:39 PM
#9
AudiWorld Super User
Thread Starter
Wait, so then this commercial was just 100% lies? Those sure look like potholes.....
https://www.youtube.com/watch?v=I6OMm_jhD4I
https://www.youtube.com/watch?v=I6OMm_jhD4I
The answer was very political. 😁
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gk1 (02-10-2020)
02-09-2020, 07:28 AM
#10
AudiWorld Member
What would be a car's ideal response to running over a pothole? (My Minnesota definition of a pothole is one that is at least half as deep as it is wide - or deeper.) From the passenger's perspective, I would like to not feel it in comfort, handling or wheel/tire damage. Except for the loss of traction/handling factor, I believe I'd like the affected wheel/tire to float right over the pothole by having the active suspension counteract the normal suspension's tendency to drop the wheel/tire into the pothole. I know the wheel rim and tire would appreciate not getting whacked against the far side of the pothole. And, if it's a deep pothole, I'm not sure the affected wheel/tire on a car with normal suspension has that much traction while searching out the bottom of the pothole.
So, maybe Audi is doing the best that can be done under the circumstances. If they had a system that could respond faster than their "6 Hz" (if memory serves) limit, there could be more possibilities for the best response to potholes...as well as bumps.
So, maybe Audi is doing the best that can be done under the circumstances. If they had a system that could respond faster than their "6 Hz" (if memory serves) limit, there could be more possibilities for the best response to potholes...as well as bumps.
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angrypengu (02-09-2020),
gk1 (02-10-2020)