Autonomous Steer By Wire

for
University of Toronto Formula SAE Racing Team

for
University of Toronto Formula SAE Racing Team

Led the design and implementation of UTFR's first fully autonomous Steering system.

Since 2023 was the first time the team had looked into Autonomous Systems, my responsibility was to find a way to actuate the steering system autonomously when the driver is not in the car. This process involved multiple iterations, bench testing and improving on each iteration. The final design was achieved in January 2024. The iterations involved are as follows:

  • Steer By Wire 2023

  • Parallel Rack Steering

  • Steer By Wire 2024


Steer By Wire 2023

My initial task as a steering member in 2023 was to design an autonomous actuation system. We implemented a BLDC connected parallel to the steering column using belt drives. Since the system had high steering torque (30Nm), the belt drives would tend to slip a lot. I tested the system with different types of belts including timing belts, V-belts, flat belts, etc. All of those belts had a slippage so a new system design needed to take place.


Parallel Rack Steering

Due to the slippage of belt drives, other option for autonomous steering actuation was to implement a parallel rack system, which basically utilized a BLDC connected parallel to the steering rack using a lead screw (as seen in the image below). This mechanism would allow for a clean and better packaging of SBW. The downsides of this system were the system was not back drivable and it was too slow since the gear ratio of the BLDC was too high (19:1).


Successful Steer By Wire 2024

After countless iterations, the final design utilized a new compact robotic BLDC with a smaller gear ratio (10:1), coupled with a chain drive system to provide higher output rpms. The design also featured an adjustable slider to modify the chain tensioning and angle in seconds. This design met all the SAE packaging and autonomous capability requirement while also meeting our team goals.