Phase 2
The basic four components that contribute to the propulsion of an electric go kart are: batteries, battery management system, motor, and motor controller. Race specifications require the use of lead acid batteries which, unlike lithium ion batteries, do not require a battery management system. Therefore, we were left to choose the motor and motorcontroller combination. The setup we purchased was the Motenergy ME1117 PMAC Motor and Sevcon Gen 4 Size 2 Motorcontroller. A permanent magnet AC (PMAC) motor is more desirable than a DC motor due to the elimination the friction of the commutation brushes. PMACs are also called brushless DC motors because they can be powered with a DC source with the use of an inverter. The Sevcon Gen 4 Size 2 Motorcontroller serves as an inverter and uses a 6-switch MOSFET bridge to produce 3 phase sinusoids from the battery voltage. The Gen 4 and the ME1117 were also offered in a conveniently assembled drivetrain package from electricmotorsport.com. We are looking forward to interfacing this powerful setup with an autonomous driving system. Most ROS projects are built around a robot using differential drive steering. As we were interested in ackermann steering, we had to do some research into how different projects worked around this. The MIT race car project proved to be very useful in understanding how to model a kart. We set up a repo for our model and began learning to use gazebo and coding the nodes we need to control the kart.
