Mo Taban

I designed a Hydraulic-Over-Pneumatic piston to actuate the brakes of the car in case of emergencies during autonomous driving. The design process involved determining the required bore size in order to achieve the desired brake line pressures. O-rings were selected based on Parker design guidelines. When power is disconnected, solenoid valves will open to apply pressure to the pneumatic input of the piston. This design has 50% greater braking performance compared to the previous generation design.

Adjustable pedals are required in order to accommodate drivers of different sizes. The brake and throttle pedal trays were redesigned with custom rails in order to eliminate the compliance caused by the OEM Rails and Carriages. The structural performance of the design was evaluated using Ansys, and it was determined that the brake pedal tray deforms by 37% less under maximum load.

The thermal and structural performance of our brake rotors was evaluated. The heat flux and convection coefficients were determined through calculations. These values were then used in Ansys to determine the temperature distribution across the rotor. The resulting thermal stresses were used as part of the structural simulation. The rotor has a minimum safety factor of 3.33 under maximum braking.

The previous Brakes Lead and I designed, manufactured, and tested our first brake by wire prototype as part of the Autonomous System Brake development. This system was designed to be a system which can be easily added to the 2023 vehicle in order to test the driverless systems. It was created in a way that it could be quickly connected and disconnected from the existing manual brakes. While this system was not formally tested on the car, many of its components and design elements have been used for the current autonomous braking system.

The throttle pedal was redesigned in order to enhance the driver comfort. This involved decreasing the pedal angle with respect to the floor. In order to achieve this, the torsion springs found in the previous design were replaced with compression springs. Because of this, the linear potentiometers which were previously used were replaced with rotary potentiometers.

In order to better understand the impact which our front and rear brake pressures have on our deceleration, I created a Python program which determines the resulting deceleration for a large set of front and rear pressure values. The data was analyzed using MATLAB in order to create a 3D plot. This figure shows all possible deceleration values, given a combination of line pressures. The Program was created with checks that ensure the behavior of the model is representative of the vehicle and tire behaviors.