by Cherif Assad
I saw an exciting demonstration last week of an off-the-shelf electric car concept by Switzerland-based Michelin Research & Technic (MRT) at the Freescale Technology Forum (FTF) in San Antonio, Texas. Called the Michelin Active Wheel System, it’s a “dressed” wheel inside the car fender that rotates depending on the road profile.
Analyst Rob Endrle shares his enthusiasm for Michelin’s wheel in action in a recent article. Here, I’ll get into some of the specifics around the technology that’s inside this crowd pleaser.
The wheel is equipped with motors for traction and suspension. The traction motor delivers 30kW of continuous power, although the second motor provides the suspension needed to lift up on bumps and stabilize the car depending on the road topology. Michelin MRT developed the motors, as well as designed the electronics and the battery pack that’s capable of handling several capacities ranging from 15KWh to 38KWh.
Now, about the electronics: There is a set of two modules: one module is dedicated to manage the two front wheel motors of the car and the second module handles the active suspension on each side. The system can be extended to the rear for a four-wheel drive. One visitor from Asia made a comment that it fits pretty well with small electric cars.
The modules are powered by Freescale Qorivva MPC5643L microcontroller, a dual-core microcontroller with failsafe mechanisms dedicated for electric motor drive capability (PWM, analog-to-digital channels that are coordinated by a cross triggering unit). The MPC5643L operates either in lock step mode (LSM) or dual parallel mode (DPM) should you need additional performance by a factor up to x 1.8. A power management device, Freescale’s MC33905 system basis chip (SBC), acts as the companion chip for intelligent power management and functional safety compliancy purposes.
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