To get a better focus on the new challenges, the most reliable elements in the previous year’s design were kept and eventually improved and adapted. Therefore, the low voltage system was kept at a working voltage of 12V, as in the previous combustion prototype, in order to reduce the necessary changes in the design of the system.
Having four in-wheel independent motors opened the possibility of implementing more sophisticated vehicle dynamics control techniques, such as torque vectoring and slip control. Thus, the need for a dedicated Vehicle Control Unit and more reliable sensors. Moreover, in the last season, many issues were caused by different families of microcontrollers mounted on the PCBs.
One of the aims for the new prototype was to solve these problems by aligning all MCUs. To enhance the system’s modularity, the LV electronics is divided in four subsystems:
- LV Power Supply and Wire Harness
- Vehicle and Dynamics Control System
- Driver Interface
- Data Management System
The low voltage part has the goal to manage all the things that involve the control of the vehicle, the data acquisition, the data management (saving and sending data to the telemetry station) and the power supply to all the boards and sensors.
The electronics consists of custom, own developed boards with ST micros, sensors and modules including a real time telemetry system with XBEE system, power distribution module, INSS-GNSS positioning and a steering wheel with 3.5’’ colour display.
All the boards and modules inside the vehicle communicate via a CAN BUS.
The entire wiring harness is self-made, and we follow the concentric twisting techniques which give us high reliability and robustness. From last year we will take the additional requirements introduced by the transition to the electrical formula student category, such as the presence of further disturbances introduced by the electrical motors.