Bose Suspension

[SiLo]

http://www.bose.com/controller?url=/aut ... /index.jsp


Something that could make it's way to F1 maybe? The video of the car that I watched on youtube is amazing. Totally stiff when needed, completely soft when needed and completely independent of each corner when needed. It's pretty impressive to be honest, it keeps the car level almost all the time.

[Jersey Tom]

But why would it make it to F1?

[Tim.Wright]

But why would it make it to F1?

Because everybody know that road car's are there to develop technology which will eventually filter down into F1..

..or filter up? or have I got it backwards?

Short answer no, its active and therefore banned.

[langwadt]

http://www.bose.com/controller?url=/aut ... /index.jsp


Something that could make it's way to F1 maybe? The video of the car that I watched on youtube is amazing. Totally stiff when needed, completely soft when needed and completely independent of each corner when needed. It's pretty impressive to be honest, it keeps the car level almost all the time.

F1 have had active suspension, it was banned some 20 year ago...

[bhall]

There's just something about a Bose suspension that sounds unnecessarily expensive and of average quality.

[olefud]

Between eddy currants and resistance, it would seem that just holding up the suspended car weight with a stalled linear motor would get things a bit toasty.

[DaveW]

Hands up those people who have blown up speakers whilst building their own DC coupled audio amplifiers.

They will know exactly why the Bose suspension won't make F1, regardless of the regulations. The actuators are powerful current drive voice coil units, and these tend to burn out amplifiers and/or their voice coils if they are required to support a steady state load for any length of time (unless they are massively over-engineered).

I recall that the current prototype carries its weight on what are called "roll over" bars.

(Apologies, olefud, you got there ahead of me).

[Tommy Cookers]

the efficiency/current economy of eg a linear motor is dependent on the efficiency of its 'magnetic circuit'
this efficiency is related to the size of the air gap (usually linear motors are poor in this respect)
but could be improved if that gap contained a suitable fluid
ie conveniently combining damper and motor/actuator functionalities ?

[DaveW]

You are probably right, Tommy, but I think the main problems occur when the coil impedance is resistive (i.e. with no back-emf to worry about).

[Tim.Wright]

A different system, but with a similar effect is already on Mercedes road cars. They call it active body control. They ues a linear actuator but the difference in this system is that;
1. Its hydraulic
2. It runs in series with a conventional spring and damper instead of replacing it.

The fact that the active element is in series with a normal spring/damper instead of replacing it means the actuator doesn't have to be so highly spec'd for velocity.

[langwadt]

You are probably right, Tommy, but I think the main problems occur when the coil impedance is resistive (i.e. with no back-emf to worry about).

unless you use super conductors the coil is always resistive back emf doesn't change that, it just subtracts from the voltage across that resistance lowering the current. Torque, or in the case of a linear motor force, is proportional to current so for higher speeds you need higher voltage to get the same torque/force

apart from the mechanics a linear motor really isn't different from a rotating motor, servo motors run much in the same
low speed high torque conditions as a linear motor would in a suspension

but I think for a suspension you would try to incorporate something in the mechanics to take up some of the static forces

[PlatinumZealot]

The way the 2013 engines will sound, we might need Bose speaker system attached to the engines!

[DaveW]

... the coil is always resistive back emf doesn't change that, it just subtracts from the voltage across that resistance lowering the current.

Interesting... In my very simple mind, the impedence of a coil is expressed as (Rc + iw.Hc + BackEMF). This will be at a minimum when the frequency (w) is zero, which also implies that the BackEMF is zero, and the impedance will be resistive (real). It is also the condition which draws the maximum current when carrying a load, leading to heating problems of the coil and the power amplifier. But perhaps this a too simple....

[DaveW]

A different system, but with a similar effect is already on Mercedes road cars. They call it active body control.

I call this the Mumford solution, largely because he was responsible for prototyping it on a Jaguar in the late 1970's, I recall, although a quick search failed to reveal a reference to the fact. In control system terms, it is similar in principle to the Citroen system, or indeed the system developed by Williams F1. It is quite difficult to stop the controlled part fighting the passive part if displacement is controlled actively. Limiting the bandwidth of the controlled part is key, I think ....

[riff_raff]

This Bose device is basically just a linear motor/generator. It is also very expensive and heavy. As others noted, similar results can be achieved with an electro-hydraulic active suspension system, such as those used in F1 20 years ago.

For many years Cadillac has used a dampener with a magneto-rheological fluid that changes viscosity when electrical current is applied, on their active stability control suspension systems.

I have also seen a company offering a dampener design that uses a linear electrical absorber, with the electrical power produced used to recharge the battery.