Introduction
UC Berkeley's EE192 Mechatronics course is a semester-long project in which teams of three students each build an autonomous electric car based on a 1/10-th scale R/C car chassis. We are allowed to use an off-the-shelf servo for steering, drive motor and MCU board, but the rest must be designed and built from scratch (this includes the motor drive power electronics, DC-DC boost converter and sensor board).
The cars sense a 75 kHz, 100 mA RMS current in a wire laid down on the floor to serve as a track. There are crossings and steps (sudden left or right doglegs). The teams compete in time trials, and the winning team gets to compete against other universities in the National Semiconductor-sponsored NatCar race.
Our team chose some additional challenges: we are designing our own MCU board based around the Atmel ATmega128 running at 16 Mhz. We are also using a brushless DC motor, commutated by the ATmega128. A commercial BLDC driver chip would have been acceptable, but we wanted to see if we could do it ourselves.
Through this blog we will attempt to document our design plans, successes and failures.