A dicycle () (also known as a diwheel) is a

vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), wa ...

with two parallel

wheel A wheel is a circular component that is intended to rotate on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machines. Wheels, in conjunction wi ...

s, side by side, unlike

single-track vehicle A single-track vehicle is a vehicle that leaves a single ground track as it moves forward. Single-track vehicles usually have little or no lateral stability when stationary but develop it when moving forward or controlled. In the case of wheeled v ...

s such as

motorcycle A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising ...

s and

bicycle A bicycle, also called a pedal cycle, bike or cycle, is a human-powered or motor-powered assisted, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A is called a cyclist, or bicyclist. Bic ...

s, which have two wheels inline. Originally used to refer to devices with large wheels and pedals, the term is now used in relation to powered self-balancing scooters with smaller wheels and no pedals such as the

Segway PT The Segway is a two-wheeled, self-balancing personal transporter invented by Dean Kamen and brought to market in 2001 as the Segway HT, subsequently as the Segway PT, and manufactured by Segway Inc. ''HT'' is an initialism for "human transpo ...

and the self-balancing hoverboard.

Etymology

In more recent usage, "dicycle" has been used for both pedaled and motorised vehicles with wheels of varying sizes, as long as they share a common

axis An axis (plural ''axes'') is an imaginary line around which an object rotates or is symmetrical. Axis may also refer to: Mathematics * Axis of rotation: see rotation around a fixed axis *Axis (mathematics), a designator for a Cartesian-coordinate ...

, though not necessarily a common

axle An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearing ...

. In 2017, the

Merriam-Webster Merriam-Webster, Inc. is an American company that publishes reference books and is especially known for its dictionaries. It is the oldest dictionary publisher in the United States. In 1831, George and Charles Merriam founded the company as ...

's dictionary, limited usage to '

velocipede A velocipede () is a human-powered land vehicle with one or more wheels. The most common type of velocipede today is the bicycle. The term was probably first coined by Karl von Drais in French as ''vélocipède'' for the French translation o ...

s with two parallel wheels,' and the

Oxford English Dictionary The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces the historical development of the English language, providing a com ...

limited it to 'pedal-powered vehicles with large wheels placed parallel to each other'.

Examples

Segway PT

The

is a two-wheeled self-balancing

personal transporter A personal transporter (also powered transporter, electric rideable, personal light electric vehicle, personal mobility device, etc.) is any of a class of compact, mostly recent (21st century), motorised micromobility vehicle for transporting an ...

which uses computers, sensors, and electric motors to keep the device upright. The rider commands the PT to go forward or backward by shifting their weight forward or backward on the platform. The maximum speed of the Segway PT is with a range of on a fully charged

lithium-ion battery A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also se ...

, depending on terrain, riding style, and the condition of the batteries. Invented by

Dean Kamen Dean Lawrence Kamen (born April 5, 1951) is an American engineer, inventor, and businessman. He is known for his invention of the Segway and iBOT, as well as founding the non-profit organization FIRST with Woodie Flowers. Kamen holds over 1,000 ...

, it is produced by

Segway Inc. Segway Inc. is a Chinese owned, formerly American manufacturer of two-wheeled personal transporters, chiefly through its Segway PT and Segway miniPro product lines. Founded by inventor Dean Kamen in 1999, the company's name is a homophone of th ...

Self-balancing scooter

The

self-balancing scooter A self-balancing scooter (also hoverboard, self-balancing board, segway or electric scooter board) is a self-balancing personal transporter consisting of two motorized wheels connected to a pair of articulated pads on which the rider places their ...

is a category of personal transporter which includes all self-balancing powered portable devices with two parallel wheels that includes the

, the Segway miniPRO and the self-balancing hoverboard.

Diwheel design

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 A monowheel, or uniwheel, is a one-wheeled single-track vehicle similar to a unicycle. Hand-cranked and pedal-powered monowheels were patented and built in the late 19th century; most built in the 20th and 21st century have been motorized. ...

, have been around for almost one and a half centuries. All of these platforms suffer from two common issues affecting driver comfort;

slosh In fluid dynamics, slosh refers to the movement of liquid inside another object (which is, typically, also undergoing motion). Strictly speaking, the liquid must have a free surface to constitute a slosh dynamics problem, where the dynamics of t ...

and tumbling (also known as gerbilling). Sloshing is when the inner frame

oscillate Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...

s, 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 Damping is an influence within or upon an oscillatory system that has the effect of reducing or preventing its oscillation. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples incl ...

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. The equations of motion for the diwheel have been published.

Gallery

References

{{Reflist

External links

US Patent Class 180/240
(lists all the vehicles coming under powered dicycles).

EDWARD, an electric dicycle by University of Adelaide studentsDi-Cycle: A Bike That Travels Over Land and Water
Land vehicles