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I've had quite a few thoughts about linked suspension since my last post.

I came to the realization that with my last design that since the hydraulic fluid pressure was the same in all of the actuators while linked, they would all be applying the same pressure down on the tires onto the pavement. What a great feature! I would have to build in an adjustable lever so that the front and rears could be balanced and there is some variation depending on the suspension height because of rising or falling rates. Wow, loading is always the same regardless of amount of extension. Wait, what happens if I push one corner of the car down with my hands....? Oh, it just stays there. There is no correcting force. Ooops.

I'll post the next sketch/idea I had in my next post when I get time.

Below is the actuator I then was thinking of using. It includes a top and bottom piston accumulator and an oil damper at the bottom. I was planning on using my own cylinder and shaft and then using Bilstein components for the rest.


Below was the spreadsheet I spent way too much time on because the interactions are pretty complicated and not intuitive. This is just linking the front and back actuators. The force/extension curves actually came out pretty well, but it is tricky to adjust the air and fluid pressures to get the curves you want and even then, there is just no way to get the curves perfect.

I was contacted by Bill who took some interest in my ideas and who has done some similar work. He gave me my current idea and it does not require me to make my own actuators. It is that of a third spring in front and back and then probably connecting the two for an anti-(double axle)-roll bar. I'll have to do the work of inboard pushrod suspension and the third spring.



This was just a quick rough sketch of it. There seem to be a few different methods of implementing a third spring. I also am not sure how exactly I will be connecting the hydraulic actuator to the front and rear seesaws attached to the third spring. I also can experiment with/without accumulator and pressures for the hydraulic line.

Advantages of the system over conventional:
-low warp stiffness
-allows soft one wheel bump while heave and pitch can be hard
-anti-roll connection does not interfere with soft one wheel bump
-could change third spring stiffness or engaging point depending on whether street or track
Disadvantages
-two wheel axle bump as hard as heave/pitch (this is very difficult/impossible for a suspension to tell the difference between that and change in pitch/heave)