Current TRL: 2 (10/26/21)

“Steering model created using CAD. Model is in the process of undergoing verification using simulation”

Steering Subsystem

The steering system is mounted on the chassis using two pillow blocks which allow the system to slide back and forth. The two arms on either side are connected to a metal rod which is then attached to the side of the wheel. The system is controlled by a rack and pinion gearbox which is further controlled by the drivers steering wheel. The picture above shows the steering arms, rack/pinion box, and how they attach to the steering wheel.

The main goal for this year’s steering team is to construct a steering system that can handle the tightest turns in the course and minimize bump steering. An analysis of the race track was done to help determine our design choices. Using this analysis and our steering research we are targeting a steering angle of 28 degrees in each wheel (parallel steering).

Main Documents

  • Endurance Track Analysis and Steering Calculations (HTML) (Last Updated: 11/1/21)
  • Test Plan (Google Drive) (Last Updated: 10/4/21)
  • Full Model (PNG)) (Last Updated: 10/4/21)

Literature Review

The chassis, suspension, and steering on a racecar need to be integrated with perfect accuracy to get the intended results. While the chassis of our electric vehicle must be designed to provide strength in the face of impact and other ride stresses, the suspension attachment points integrated into the chassis largely affect the dynamics of the system. Additionally, our front suspension must be designed to create safe steering conditions as shock deflection can change wheel steer angle, camber, caster, etc. These same angle effects of the rear suspension deflections can cause instability in steering as well. While each subsystem has an individual function, we see that they are very interconnected, making cross subsystem study and integration of vital importance

Full Literature Review

Components:

Actuator Assembly

This piece allows the gear rack to slide back and forth smoothly. The arm slides through the shown pillow block to control the angle of the wheels using a tie rod. This piece also limits how much the rack can slide back and forth which is a major consideration with our design. We will need to manufacture or buy these parts.

Documents 

  • Clevis Rod End (McMaster-Carr) (Last Updated: 10/4/21)
  • Actuator Coupling (PNG) (Last Updated: 10/4/21)

Rack and Pinion

The main gear system of a steering system. This converts the rotational movement of the steering wheel into translational movement in the actuator arms. We have a prebuilt rack and pinion system. In its current setup, the rack and pinion do not allow the wheels to steer more than 14 degrees which is very low for a race car.

Subsystem TRL Chart

TRL What does this look like? Expected Completion Date
9 Steering performs successfully in competition May 2022
8 High-speed turning test Feb 2022
7 High-speed straight-line tracking test Feb 2022
6 Low-speed test with power from the drivetrain Feb 2022
5 Rolling chassis test in the parking lot for steering model validation Dec 2021
4 Fully manufactured steering system tested in the lab 11/23/21
3 Model tested dynamically in simulation 11/16/21
2 Steering model created using CAD Current
1 Steering model type chosen Completed