Design of Centaurus II
Centaurus II is the University of Minnesota's 9th generation solar vehicle. Design work on Centaurus began in earnest in the late fall of 2008, and major construction began in the fall of 2009. The car was completed in early June of 2010, and took 2nd place in the 2010 American Solar Challenge.
Traditionally, solar cars have required the driver to lay down inside the car. However, the 2007 World Solar Challenge and 2008 North American Solar Challenge regulations were significantly altered from before, requiring drivers sit upright, which has prompted large changes in the exterior design of solar cars. The Centaurus II aerodynamics team had to deviate significantly from past designs to accomadate this. Unlike Centaurus I, which had a flat bottom, Centaurus 2 utilizes a curved underside to allow for a thinner main body section. A variety of designs were created in SurfaceWorks, and tested in Ansys/CFX. Once a design was chosen, female molds were created in order to produce the actual aeroshell through a wet-resin fiberglass over nomex core lay-up process. Fiberglass was chosen for both the top and bottom of the car this year due to its light weight and lack of electrical conductivity.
One of the many things that the team takes great pride in is the car's solar array. The UMNSVP is one of the very few collegiate teams that research, test, string, encapsulate, and assemble their entire solar array in-house. Market availability of bare cells forced the team to choose monocrystaline silicon cells from China Sunergy over slightly more efficient silicon cells, or gallium-arsenide cells like those used in the Borealis series cars. The array team used a new, proprietry 3M anti-reflective encapsulation process to construct Centaurus IIs solar array to exacting standards.
The team is extremely proud that nearly all of the electrical components on the car are designed and manufactured in-house. Building off of years of work done by previous teams, the Centaurus I electrical team had redesigned all of the electrical systems on the car with an eye towards reliability and ease of maintenance. For Centaurus 2, the team switched to a more reliable and higher bandwidth digital CAN bus for all of the electrical communication on the car, as well as redesigning all of the components for greater reliability and ease of manufacture. Improvements to the power trackers, battery protection, telemetry, and driver interface circuitry have been coupled with a re-written and cleaned up codebase. Starting in early spring, the electircal team brought Borealis 3 out of retirement to use as a rolling test chassis to allow them to debug their systems in a production environment. As a result of this, we believe that Centaurus II will be one of the most electircally reliable cars the team has ever built. At the 2010 American Solar Challenge, the team was proud to recieve the award for Electrical Excellence.
The mechanical team produces one of the most reliable and cleanly designed cars in collegiate solar racing. Improving on the excellent reliability and durability of Borealis II, Borealis III, and Centaurus I, the team continued to optimize previous designs. The chassis was constructed using our traditional fiberglass composite panel construction, however, this year, much lighter panel was used, resulting in a lighter car. Centaurus 2 weights 390lbs without a driver; it is one of the lightest cars that the teams has ever built. Double A-arm suspension is used up front, while a single swing-arm is utilized in the rear.