4×4 direct drive RC car

For the first post in new category – electronics, I have decided to share a first glimpse of the project I’m working on for my diploma thesis. It is a model of electric vehicle, more precisely radio-controlled model car, driven by four microprocessor-controlled three-phase brushless (BLDC) electromotors. Rear motors are controlled by custom BLDC drivers based on PIC18 MCUs, front motors by custom driver based on STM32 MCU (my colleague’s work). These three communicate via SPI with the main computer – our beloved Raspberry Pi (currently model B with a mess of wires SPI level converter shield).


Electric mobile model with BLDC driver prototypes. Sorry for the image quality, the N900’s camera sensor isn’t what it used to be (will explain in another post)

The vehicle’s chassis is based on standard 1:10 plastic model chassis, but heavily modified by enlarging external dimensions and using four motors directly connected to wheels. The new chassis was designed in AutoCAD and milled from plates of Textit (cotton/formaldehyde laminate).

AutoCAD drawing of model’s rear axle

Currently, the BLDC driver prototypes are being tested and different power MOSFET cooling options are considered. This thing can eat up quite a lot of power to start moving! I will post more info about the development later. Hopefully also schematics, layouts, source codes and other files, but I’ll need to get my university’s approval for that.

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