The mecanum wheel is an omnidirectional wheel design for a land-based

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), ...

to move in any direction. It is sometimes called the Swedish wheel or Ilon wheel after its inventor, Bengt Erland Ilon (1923–2008), who conceived of the concept while working as an

engineer Engineers, as practitioners of engineering, are professionals who Invention, invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considerin ...

with the Swedish company Mecanum AB, and

patented A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...

it in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

on November 13, 1972.

Design

The mecanum wheel is a form of

tire A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), t ...

less wheel, with a series of

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

ized external

roller Roller may refer to: Birds *Roller, a bird of the family Coraciidae * Roller (pigeon), a domesticated breed or variety of pigeon Devices * Roller (agricultural tool), a non-powered tool for flattening ground * Road roller, a vehicle for compa ...

s obliquely attached to the whole circumference of its rim. These rollers typically each have an

axis of rotation Rotation around a fixed axis is a special case of rotational motion. The fixed- axis hypothesis excludes the possibility of an axis changing its orientation and cannot describe such phenomena as wobbling or precession. According to Euler's r ...

at 45° to the wheel plane and at 45° to the

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, beari ...

line. Each Mecanum wheel is an independent non-steering

drive wheel A drive wheel is a wheel of a motor vehicle that transmits force, transforming torque into tractive force from the tires to the road, causing the vehicle to move. The powertrain delivers enough torque to the wheel to overcome stationary for ...

with its own

powertrain A drivetrain (also frequently spelled as drive train or sometimes drive-train) is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the drivetrain is the components o ...

, and when spinning generates a propelling force perpendicular to the roller axle, which can be

vector Vector most often refers to: *Euclidean vector, a quantity with a magnitude and a direction *Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematic ...

ed into a longitudinal and a transverse component in relation to the vehicle. Mecanum wheel control principle

The typical Mecanum design is the four-wheel configuration as demonstrated by one of the URANUS omni-directional mobile robot (pictured) or a

wheelchair A wheelchair is a chair with wheels, used when walking is difficult or impossible due to illness, injury, problems related to old age, or disability. These can include spinal cord injuries ( paraplegia, hemiplegia, and quadriplegia), ce ...

with Mecanum wheels (similar to that pictured)., with an alternating with left- and right-handed rollers whose axles at the top of the wheel are parallel to the

diagonal In geometry, a diagonal is a line segment joining two vertices of a polygon or polyhedron, when those vertices are not on the same edge. Informally, any sloping line is called diagonal. The word ''diagonal'' derives from the ancient Greek δ� ...

of the

vehicle frame A vehicle frame, also historically known as its ''chassis'', is the main supporting structure of a motor vehicle to which all other components are attached, comparable to the skeleton of an organism. Until the 1930s, virtually every car had a ...

(and hence perpendicular to the diagonal when at where the bottom of the wheel contacts the ground). In such a way, each wheel will generate a

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

roughly parallel to the corresponding frame diagonal. By varying the rotational speed and direction of each wheel, the

summation In mathematics, summation is the addition of a sequence of any kind of numbers, called ''addends'' or ''summands''; the result is their ''sum'' or ''total''. Beside numbers, other types of values can be summed as well: functions, vectors, ma ...

of the force vectors from each of the wheels will create both linear motions and/or

rotation Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional ...

s of the vehicle, allowing it to maneuver around with minimal need for

space Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consi ...

. For example: * Running all four wheels in the same direction at the same speed will result in a forward/backward movement, as the longitudinal force vectors add up but the transverse vectors cancel each other out; * Running (all at the same speed) both wheels on one side in one direction while the other side in the opposite direction, will result in a stationary rotation of the vehicle, as the transverse vectors cancel out but the longitudinal vectors

couple Couple or couples may refer to : Basic meaning *Couple (app), a mobile app which provides a mobile messaging service for two people *Couple (mechanics), a system of forces with a resultant moment but no resultant force *Couple (relationship), tw ...

to generate a

torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...

around the central

vertical axis A Cartesian coordinate system (, ) in a plane is a coordinate system that specifies each point uniquely by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in ...

of the vehicle; * Running (all at the same speed) the diagonal wheels in one direction while the other diagonal in the opposite direction will result in a sideways movement, as the transverse vectors add up but the longitudinal vectors cancel out. A mix of differential wheel motions will allow for vehicle motion in almost any direction with any rotation.

Use

The

US Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

bought the patent from Ilon and put researchers to work on it in the 1980s in

Panama City, Florida Panama City is a city in and the county seat of Bay County, Florida, United States. Located along U.S. Highway 98 (US 98), it is the largest city between Tallahassee and Pensacola. It is the more populated city of the Panama City–Lynn ...

. The US Navy has used it for transporting items around ships. In 1997, Airtrax Incorporated and several other companies each paid the US Navy $2,500 for rights to the technology, including old drawings of how the motors and controllers worked, to build an omnidirectional

forklift truck A forklift (also called lift truck, jitney, hi-lo, fork truck, fork hoist, and forklift truck) is a powered industrial truck used to lift and move materials over short distances. The forklift was developed in the early 20th century by various ...

that could maneuver in tight spaces such as the deck of an

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a ...

. These vehicles are now in production.

Tracked vehicle Continuous track is a system of vehicle propulsion used in tracked vehicles, running on a continuous band of treads or track plates driven by two or more wheels. The large surface area of the tracks distributes the weight of the vehicle ...

s and skid steer vehicles utilize similar methods for turning. However, these vehicles typically drag across the ground while turning and may do considerable damage to a soft or fragile surface. The high friction against the ground while turning also requires high-torque engines to overcome the friction. By comparison, the design of the Mecanum wheel allows for in-place rotation with minimal ground friction and low torque. One of the most prominent youth robotics organizations in the world,

FIRST Tech Challenge FIRST Tech Challenge (FTC), formerly known as FIRST Vex Challenge, is a robotics competition for students in grades 7–12 to compete head to head, by designing, building, and programming a robot to compete in an alliance format against other te ...

, is one of the most wide use cases for Mecanum wheels. FTC teams need to move efficiently on the field in order to score the most points possible, so many teams have adapted Mecanum wheels from suppliers such as Nexus and GoBilda. 506 Pandara Drivetrain

References

External links

Airtrax video
* ''Orlando Business Journal'' articl

by Chad Eric Watt, 31 May 2002. * ''The Wall Street Journal'' onlin
''Make It''
by Paulette Thomas, 9 May 2005.
Video of a wheel chair with Mecanum wheels (WMV)
The wheel chair was presented at the 2006

EVER Monaco EVER Monaco is annual exhibition and conference event showcasing the latest renewable energy technology with a focus on vehicle design. "EVER" is a (somewhat flawed) acronym for "ecologic vehicles and renewable energies." The Venturi Fetish, t ...

.
Segway RMP
Photos of a 2008 Segway robot with Mecanum wheels. * CMU'
"Tessellator"
robot designed in 1992 for servicing Space Shuttle tiles used Mecanum wheels. * CMU URANUS Mobile Robot, the first mobile robot with Mecanum wheels built in 1985 and used for two decades for autonomous navigation research.{{cite journal , last1=Podnar , first1=Gregg W. , title=The URANUS Mobile Robot , journal=Autonomous Mobile Robots Annual Report 1985, Mobile Robot Laboratory (CM U-KI-TK-86-4) , year=1985 , pages=127–129 , url=https://www.ri.cmu.edu/pub_files/pub3/moravec_hans_1985_2/moravec_hans_1985_2.pdf , url-status=live , archive-url=https://web.archive.org/web/20081203192312/https://www.ri.cmu.edu/pub_files/pub3/moravec_hans_1985_2/moravec_hans_1985_2.pdf , archive-date=2008-12-03 Swedish inventions Mechanisms (engineering) Wheels 1973 introductions

Design

Use

See also

References

External links