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Currently functional:
emergency braking
distance sensing & dash display of calculated values (stopping distance, speed, etc.)
Current plans include:
implementing adaptive cruise control
implementing full self-driving with open pilot by comma ai.
This will require multiple upgrades, including electric power steering, mechanically actuated brakes, and a computer with NVidia Cuda cores.
At just 26 inches wide, I have yet to encounter a doorway too narrow for this go-kart to navigate!
We utilize a Garmin LIDAR-Lite V3HP for both emergency braking and adaptive cruise control functionalities. With an impressive range of over 30 meters and a waterproof design, the Garmin sensor was an obvious choice. Additionally, we've been impressed by the comprehensive documentation and exemplary code samples provided by Garmin.
With six tiny 24AWG conductors, it was rather difficult to find a connector solution! We eventually settled on JST JWPF connectors. Not only do these perfectly fit the conductors, but they're also waterproof and relatively inexpensive.
Installing the DALY BMS (battery management system) onto the recycled Lithium Ion pack from a data center.
Shown here is the initial phase of our project. The kart is equipped with a high-performance 2.4HP brushless 48V electric motor, controlled by a Kelly KEB Brushless Motor Controller. We determined that upgrading the motor controller was essential for integrating adaptive cruise control and emergency braking functionalities, given its support for programmable regenerative braking.
For power, we repurposed batteries sourced from a data center and sourced a suitable DALY BMS (battery management system). While these batteries deliver impressive power output, their energy output is limited. Originally designed to sustain server operations only until shutdown during power outages, they are optimized for short bursts of power. Rated for an impressive 100+ amps discharge, they charge at a comparatively slow rate of only 4 amps. Operating at 48V and having approximately 6AH, they provide us with around 300 watt-hours, scarcely sufficient for 20 minutes of testing. Fortunately, we have multiple battery packs readily available for extended experimentation.
The finished pack on the go-kart. The clear heat shrink battery cover helps hold everything in place and provides marginal protection. As a bonus, it allows us to inspect the battery, BMS, and balance leads very easily.
Reducing the battery voltage to a minimum helps mitigate expenses and uphold safety standards. On campus, apart from the Formula SAE team, I am unaware of any other student organization handling larger lithium battery packs. Within their program, the formula SAE rules mandate staff or professional oversight when dealing with voltage levels exceeding 60V. Although my research suggests that 30V is considerably safer, motor options in this range are limited. Thus, we opted for 48V as a compromise between the voltage levels which would allow us the most power, and lower, safer voltages requiring less expense and safety measures.
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