Researchers cite three inspirations for their design — the awesome Droidekas from the Star Wars fanchise, the mascot Haro from the Gundam anime series, and the existing spherical transforming robot MorpHex, which can also switch from a roll to a walk. The QRoSS robot is similar to the MorpHex, but it has one significant difference. While the MorpHex incorporates its legs into the shell, the QRoSS separates the walking system from the shell.
The QRoSS is constructed using a central pole that is enclosed inside a spherical roll cage. When not in use, the legs are stored safely inside this shell, which protects the robot from falls and allows it to roll smoothly across a surface. When it’s time to walk, the robot activates the twelve servos that are used to control its legs, which are constructed from titanium and shape-memory alloy along with polyurethane foam shock absorbers. The four legs extend out from the central pole and move independently from the stationary roll cage shell.
This design allows the robot to traverse difficult terrain by alternating between rolling and walking depending on the condition. Better at rolling than walking, QRoSS has a maximum walking speed of approximately about 0.1 m/s, while its rolling speed tops out at 0.6 m/s.
Currently, the QRoSS robot is on the larger size, weighing almost 2.4 kilograms and measuring 30-centimeter in diameter. As a result, the robot is not optimized for throwing due to its larger size. Hopefully, a future version of QRoSS will shrink the dimensions of the robot and allow it to be a truly toss-able device.