Quote:
Originally Posted by EarlQHan
Too many deltas!  I was thinking state-space might be a better way to model the suspension so you can do transient analysis. This, including modeling the driver-vehicle feedback loop as the base block diagram is what I want to do my masters (or possibly doctorate) research and thesis on. But that's just too much math and I'm going to say EF IT for now lol. |
This IS state-space. People like to use that term to indicate magic.
Variables take specific states, which interact based on a set of differential equations (some complex some simple).
What are your states? You can consider either the ground or the car body to be fixed... it's just perspective (although it matters that you pick one and stick with it). We care about tire deflection (x) and shock displacement (y). Thus the states are:
Q =
[ x ]
[ y ]
[ x' ]
[ y' ]
[ x'' ]
[ y'' ]
Your state space matrix will have diagonal elements to define the derivatives:
Q' =
[ 0 0 1 0 0 0 ] * Q
[ 0 0 0 1 0 0 ]
[ 0 0 0 0 1 0 ]
[ 0 0 0 0 0 1 ]
[ 0 0 0 0 0 0 ]
[ 0 0 0 0 0 0 ]
You can fill in the rest of the elements using the force balance equations in any level of complication you desire... but stiffness and damping components will appear, scaled by mass.
Solving the state space version is the same as solving the diff-eq version is the same as solving the numerical version. I'm sure you know all this, but it's good to lay it out there for the forum to glance over.
Good luck with the Master's btw. Where are you planning to go to school (or are already there)?