Design of Emergency brake system for Formula Student Driverless car

The Formula Student competition for Driverless Vehicle (DV) class requires the students to develop a car that can autonomously make its way around a cone track in addition to several other static and dynamic tests. To ensure safety of such a vehicle without a driver, an Emergency Brake System (EBS) is required. The Emergency Brake System (EBS) shall ensure safe stoppage of the vehicle when any predefined failure modes get triggered. This thesis focuses on the design and development of the Emergency brake system (EBS) for the Formula Student car (SC19) which is predominantly developed as a car with driver. The primary braking of the Driverless vehicle (DV) will be performed by “Brake-by-wire” while the Emergency brake system (EBS) is designed exploiting the already existing hydraulic brakes (service brake) of the vehicle. Behind the brake pedal is an arrangement of a hydraulic actuator driven by a Hydro-pneumatic intensifier, solenoid actuated valves and a pressure-regulated high-pressure gas cannister. When engaged, the hydraulic actuator connected to the brake pedal pulls it, thus imitating a driver applying brakes manually. Owing to the minimal space available inside the cockpit and the Formula Student regulations, the EBS is designed as a hydro-pneumatic system whose combination provides the required pressure output as well as a compact assembly to be mounted inside the cockpit. The design specifications of the EBS comes from several design parameters in various vehicle systems such as Brake pedal gain and travel, Brake overtravel switch actuation, Brake master cylinders, balance bar, brake caliper and brake pad, brake discs and tires in addition to vehicle weight, load transfer while braking and the test surface conditions. The brake pedal along with pedal box base plate is modified to accommodate the actuator and FEA is performed to ensure the limit of safe stresses. The overall system has been developed using CATIA™, Stress analysis using Altair Hyperworks and Microsoft Excel calculator for the brake force calculation. All calculations, design and analyses are performed complying to Formula Student regulations 2020.