Steering

Objective

    The objectives of the steering system of the University of Windsor’s SAE Mini Baja team has been to design and implement a durable, simple, and free of bump steer vehicle. These goals have been succeeded by implementing a rack and pinion steering system. When the steering wheel is turned, it will turn a gear (pinion) which will translate a rack as a result of their interaction. As the rack is moved off center by the motion of the pinion the vehicle will turn to the right or to the left as desired.

Tie Rods & Uprights

    At each of the rack ends there is a tie rod attached, which fastens to the front wheel uprights. The tie rods are usually fastened to the uprights off center so that when the rack is moved it will either push or pull the wheel and this is what essentially causes the vehicle to turn. Throughout the years, the University of Windsor SAE Mini Baja team has aimed to optimize the bump steer in the design of the steering system.

Ackermann Steering Geometry

    The steering geometry is chosen to follow that of an Ackermann steering geometry as much as possible. According to the Ackerman geometry all the wheels on a car must pivot about a common point when the car is performing a turn (rotation). This also means that the inner wheels must turn at a sharper angle then the outer wheels. One important aspect to consider when designing the steering system is the steering ratio.

Steering Ratio

    The steering ratio is the amount the steering wheel has to be turned in order to obtain a certain tire angle. In the past years, the steering ratio has been decided to be 4 to 1, this would provide a 45° steer angle of the tires with a 180° input to the steering wheel. The rack and pinion generally consisted of a rack having 1.5 turns lock-to-lock and 5 inches of total travel is usually selected, allowing for an overall steering ratio of 6.2 when installed in the vehicle. The steering system is usually analyzed in ADAMS’s Car.

ADAMS’s Car Models

    ADAMS's Car is a computer software that can be used to analyzed many different types of vehicle steering setups. Below are some pictures of our ADAMS simulation.