The diwheel design has the two large outer wheels completely encompassing an inner frame. The inner frame is free to rotate within the wheels, and is typically supported by a common axle or idlers which roll on the wheels (see figure). Diwheels, like their more popular cousins the monowheel, have been around for almost one and a half centuries. All of these platforms suffer from two common issues affecting driver comfort; slosh and tumbling (also known as gerbilling). Sloshing is when the inner frame oscillates, and it occurs in all monowheels and diwheels where the centre of gravity of the inner frame is offset from the centre line of the wheels. It is very prevalent as these platforms typically have low damping between the wheel and the frame, to minimise power consumption during locomotion. In addition, during severe braking or acceleration the inner frame will tumble relative to the earth centred frame, which affects the ability of the driver to control the platform. Both the sloshing and tumbling issue can be controlled through feedback control, and has been demonstrated successfully in the diwheel called EDWARD.
US Patent Class 180/240 lists all the vehicles coming under powered dicycles. This class has patents related to unmanned folding vehicles to be used for tactical purposes by the US government. Other vehicles in this US Patent Class are mostly invented by Dean Kamen or his associates, like the Segway PT, a balancing dicycle.
Equations of motion
In popular culture
- B. Cazzolato, J. Harvey, C. Dyer, K. Fulton, E. Schumann, C. Zhu and Z. Prime (2009) "Control of an electric diwheel". http://data.mecheng.adelaide.edu.au/robotics/projects/2009/EDWARD/DiwheelPaper_v3.pdf paper
- Dicycles and Diwheels throughout history
- EDWARD - Electric DiWheel with Active Rotation Damping
- http://www.fabels.org/fred.html Dicyclet - pedal driven Dicycle by Dutch artist Fred Abels