Due to a change in the Formula Student regulations, no significant modifications to the monocoque concept were required for the first time this season. Since the revised monocoque geometry introduced on the eax03 had already optimized the aerodynamic performance for its successor’s vehicle concept, this season the focus could be placed on refining the laminate lay-up in order to achieve even higher torsional stiffness and improved load absorption, thereby further enhancing the vehicle’s handling characteristics.

Last year, the front wing was redesigned with improved aerodynamic performance, thereby laying the foundation for the eax04’s aerodynamic package. To fully exploit the resulting potential, the eax04 features an adapted tunnel geometry that takes advantage of an increased mass airflow and, in combination with the newly developed rear wing main element, optimizes the pressure distribution in the underbody across all vehicle attitude conditions. A new manufacturing concept for the underbody, together with structural modifications to the existing components, enables a weight reduction of the new aerodynamic package.

A major focus this year was gearbox development. While in previous years the selection had still been based on empirical values, this year we were able for the first time to identify the optimal configuration for our application through extensive automated simulations covering several million gearbox variants— a genuine unique selling point in Formula Student. This now enables us to monitor the powertrain units in real time and to carry out targeted data-driven optimizations in the future. Last but not least, a revised motor bearing concept ensures even more stable operation, while tailor-made sealing solutions reduce power losses to a minimum.

The most significant innovation in the high-voltage system is the interaction between a new inverter and a revised HV battery. By introducing laser welding and modifying both the stack design and the battery enclosure, components and manufacturing processes were simplified while reducing overall weight at the same time. An optimized cable routing layout and an adjusted positioning of the cell plates also facilitate maintenance and service operations.

In the low-voltage system, the operating voltage was increased from 42 V to 60 V. This enables more efficient power distribution and the use of smaller cable cross-sections, resulting in further weight savings. Power is supplied either by the HV battery via an in-house developed DC/DC converter or by a weight- and capacity-optimized LV battery featuring a new battery management system (BMS). The Power Distribution Unit (PDU) was also revised to further improve power distribution within the vehicle.

The system is complemented by new sensors for recording validation and performance data, as well as by an in-house developed and optimized data logger and an LTE telemetry system for reliable data transmission during test drives and events.

The task of the Driverless Software group is to navigate known and unknown tracks without any intervention from a human driver. Our main objective this season is to improve the reliability of the entire autonomous system and to score as many points as possible in all disciplines at the summer events. We extract the position and color of the track markers from our surroundings at distances of up to 60 meters. Using the cone positions together with our other sensors, we localize ourselves and map the environment. Our software computes an optimized trajectory and follows it using a model predictive controller. Off the track, we use our end-to-end simulation to test and further improve all modules of our software.

Direct feedback from the car to the driver is crucial to the ultimate performance of a race car. With the new steering system of the eax04, we have not only succeeded in transmitting steering torque more directly between the tires and the driver, but also in reducing the weight of both the manual and autonomous steering systems by a total of 14 percent. In-house developed master brake cylinders, brake calipers, and an optimized accelerator pedal complete the overall package and enable the driver to push the car to its dynamic handling limits.