Steering

I led the design, manufacturing, and assembly of the Steering system for the Columbia's Formula SAE vehicle during the 2023-2024 cycle.

I defined the goals of the Steering 2023-2024 system to be the improvement of system ergonomics and tuning of the bumpsteer behavior. These goals led me to modify the steering column layout and the location of the steering rack, and further testing and observations of significant compliance within the system motivated me to make further changes to the system to correct these issues.

To achieve all these goals, I led a small team of students through Computer Aided Design development using SolidWorks, manufacturing, and assembly processes, often getting intensely involved with each of the steps of system development first hand.

Skills developed:

System and component design
Cross-system integration
Metal machining
Validation and testing
Tuning

Software utilized:

SolidWorks (CAD, FEA)
OptimumKinematics (bumpsteer)
Autodesk Fusion 360 (CAM)

Tools put to use:

CNC mill (Haas Mini-Mill)
Waterjet (Ward A-0612)
Bumpsteer gauge
3D printers
Hand tools

Ergonomics & Kinematics

In the previous year the steering system had received comments that the car was difficult to drive due to the inconvenient placement of the steering wheel. Therefore, in 2023-2024 design cycle I was aiming to improve the driver comfort by modifying the location of the steering wheel to be higher and further away from the driver.

To achieve this change, I redesigned the geometry of the system for a different location of the steering wheel while keeping in mind the design constraints imposed by the double U-joint system and by the competition rules. I made sure to keep the operating angles of the U-joints equal to one another and below the 20 degree limit recommended by the manufacturer and modified the steering column arrangement accordingly.

Bumpsteer

During the testing of the previous year's car, the team discovered that it experienced significant bumpsteer effect, making the car unstable during the braking events. Therefore, during the development of the 2024 year car, I had organized a sustained effort directed towards the tuning of the bumpsteer.

I first designed and printed a bracket that allowed for adjustment of the tie-rod attachment point up and down, allowing us to quickly modify the bumpsteer behaviors and record the results. The team and I then used a bumpsteer measuring rig to obtain data at different z-heights of the tie-rod attachment point, allowing us to adjust the car to have symmetric bumpsteer behaviors across its centerplane.

Visualization of the untuned bumpsteer effect.

3D-printed bracket attachment to steering rack that was developed for bumpsteer tuning. It allows the inboard tierod connection height to be adjusted, which changes the arc in which the outboard point of the tierod travels as the wheel moves up.

Bumpsteer measurement setup.

Data collection for bumpsteer visualization and tuning illustrated in a graph. On the y-axis, the toe-in and toe-out behaviors are measured in degrees; on the x-axis, the jounce (upward motion of the suspension measured at the wheel) is measured in inches.

Triangulation

Closer to the completion of the 2024 vehicle's assembly, we discovered that the blocks used for clamping the steering rack to the chassis tended to deflect a lot during the motion of the steering rack, which had a potential of making the car undrivable. To fix it, I triangulated the clamping blocks to the adjacent chassis tubes, thereby constraining their motion in lateral directions.