Summary
- A customized ergonomic formula SAE steering wheel over 40% lighter than current solution (943g).
- Modeled from grip-molded clay model andresurfaced in NX. Utilized carbon fiber composite material and aluminum toachieve strength while saving weight.
- Manufactured using waterjet-cut, CNC-milling,and 3D printing.
This project involved redesigning an ergonomic steering wheel for the USC Formula SAE Racing Team with a focus on reducing weight and improving driver handling. Over 40% weight reduction was achieved by using a composite central board made from a honeycomb structure, while an aluminum machined central hub was employed to maintain structural rigidity.
Ergonomic 3D-printed grip handles were developed using NX surfacing tool and photogrammetry of clay models, tailored to individual drivers. A generalized grip handle was also created for maximum compatibility.
The design was validated through Finite Element Analysis (FEA), and real-world strength and torsional rigidity testing using a hydraulic press and weight scale. The thickness of the composite material has been validated to withstand external loading of 800N. A hall-sensor switch powered paddle shifter was embedded in a waterproof plastic enclosure which also housed two push buttons, enhancing functionality in diverse racing environments.
Design Targets
- Ergonomic Improvement: Aim to enhance the hand gripping experience by transitioning from the original uniformly rectangular, 3D-printed handles of the steering wheel to customized handles tailored for better ergonomics.
- Weight Reduction: Aim to reduce the weight of the steering wheel while retaining the requisite rigidity for the Formula SAE competition.
- Button Arrangement: Aim to reorganize the arrangement of pressable buttons for easier access and improved control of the car for the drivers.
- Design for Assembly: The original steering wheel integrated with a paddle shifter system took over ten minutes for assembly or disassembly. The goal is to employ a modular design approach, separating the paddle shifter system, to simplify maintenance and expedite replacement processes.
Highlights
Photogrammetry and Clay Modelling
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To create a grip handle that fits drivers’ hand, a clay model is made before the actual CAD of the steering wheel. By having the shape of gripping with racing gloves, it is then scanned for CAD.
Without available laser scanning resources, photogrammetry is used to create a reflection of the clay model in 3D sculpting environments. With NX surfacing tool, the grip handle can be recreated with nearly class-A surfaces.
Composite Material Testing and Selection
To satisfy the rigorous operation condition in formula SAE racing, the steering wheel will need to withstand 650N of lateral force(z-axis) and over 20Nm of torque. Due to the usage of composite materials, with the properties of materials varies due to different in-lab manufacturing conditions ,real life testing is involved to determine the thickness of the steering wheel. Several thicknesses of composite material have been tested to evaluate the final thickness of composite centerboard. With the thickness of ½’’, the centerplate will be able to withstand the requirement and reaches ultimate strength at 180lbf (800N).
