suspension potentiometer, advantageous?
suspension potentiometer, advantageous?
(OP)
I would like to setup suspension potentiometers on our cars to get a better understanding of what is happening with our suspension. However, not having done it before or seen any actual data from them, I would like to ask what the main advantages are, the best way to interpret the data, and mounting practices to follow. They are the linear telescoping type.
Thanks
Thanks





RE: suspension potentiometer, advantageous?
They are probably the world leader in linear measuring, and in fact, already make linear sensing components for the automotive industry. Check out their low cost line of sensors.
For most of their sensors at least, the output is already conditioned to a linear 0-10VDC.
Hope that helps.
RE: suspension potentiometer, advantageous?
Personally, I would mount the pot in-line with the dampers. Use the information to determine the actual piston speed of the damper during ride comfort events, and handling maneuvers. By knowing the piston speeds of various events, you can help out the damper manufacture tune the damping curve in the exact area you request to improve, by being able to tell them EXACTLY what is happening. In this case you would be measuring velocity, but you can also measure the displacement and use the lever ratio to determine the angles of your suspension links.
Anther thing to try is mount the pot in-line with the control arms. One at each body/crossmember mounting point to check bushing compliance during handling maneuvers.
RE: suspension potentiometer, advantageous?
First, in-line mounting is accurate and not need to calculate so it will be godd choice, and for this purpose you have to make some brackets to hold the potentiometer, and also the damper, though it may be struts, or just shocks, it will be bend slightly, the upper and lower of the potentionmeter to be connected by rod end bearing.
Second, the potentiometer is easily damaged when you
measure it in harsh environment. You must find a rugged
one to save your money.
RE: suspension potentiometer, advantageous?
measure it in harsh environment."
When I brought this up with our DAQ company we work with, they actually suggest string pots. I know what your thinking...no way. But actually, after looking into some of the string pots available from a company called space age control ( www.spaceagecontrol.com ) I think they will work. hey are meant for very harsh environments, and have great load and acceleration limits. I haven't used them personally, but I think they would work.
RE: suspension potentiometer, advantageous?
Cheers
Greg Locock
RE: suspension potentiometer, advantageous?
RE: suspension potentiometer, advantageous?
Shock absorber velocities on a race car tend to top out at 2 m/s. On a road car 5 m/s (yes, those are the right way round).
Frequencies - anything above 5 Hz can probably be filtered out if you are interested in handling only.
Cheers
Greg Locock
RE: suspension potentiometer, advantageous?
Thanks
Travers
RE: suspension potentiometer, advantageous?
Depends on what you mean by upsetting the chassis, if you are serious you need to go to 40 Hz - not practical with string pots.
I don't know what the frequency response for tyres is as far as grip goes - but time constants associated with tyres are typically of the order of hundreds of milliseconds. 5 Hz is fine AFAIK.
Shocks will react to frequencies as high as the bushes at each end will let them go - if the displacements are high enough. Typically the bushes provide isolation above 20 Hz, but if you use rod ends (spherical joints), again I'd be looking at 50 Hz or thereabouts.
So my conclusion is if you want to study all the dynamics of chassis supension interactions you'll need eaccelerometers and 40-50 Hz cutoff. if you just want handling then you cn use stringpots or LVDTs, and a 5 Hz cutoff.
Cheers
Greg Locock