Steering Linkage Optimization
- Jens Dekker
Buckle up, this is going to be a big one.
Currently where the steering system sits relative to chassis is bad. The main unit, the rack and pinion will likely interfere with the occupant’s legs, and will likely interfere with chassis tubes as is. This task is to come up with a new linkage system nodal diagram so the system will not interfere with the occupant or the chassis, while being slightly optimized for Ackerman Geometry.
So, how do we define a linkage system? Well I use 4 main parameters to do it as can be seen in this desmos link Steering Linkage Simulation. This is a simulation of the linkage system I created that you can play around with to get an idea of what each of the sliders do. I’ll quickly note “Track” from the desmos isn’t really the track of the car, but the distance between the two steering axes, and is also the 5th parameter, but it is more of a given.
The distance between axes is a given because of the Parametric Design File in the CAD files attached, the lines with represent the steering axes for the wheels are not parallel, this means the distance between the axes can vary. By looking at the distance between the axes on any given plane parallel to the Top Plane, you can define the distance between axes. If you set a height, relative to the top plane, you can find the distance between the axes, and thus define the 5th parameter.
Now you need to determine the other 4 parameters. First thing is to make sure the new system you define would fit in the chassis as it currently sits, then look at optimizing the system for Ackerman Geometry.
The MatLab files I attached are the (messy) collection of scripts I used to determine the relative closeness of a linkage system to Ackerman geometry. I recommend using the single config test script and changing some of the variables in there to test new linkage systems.
I know this is a lot to take in, my suggestion would be to take a look at the CAD files to familiarize yourself with the geometry we have, and to start looking through the MatLab scripts to get an idea of how they run. You don’t need to know all the details, just what variables correspond to what variable in the linkage simulation in Desmos.