Tilting three-wheeler

Last updated April 14, 2024

Terminology

Because this is an emerging field with many different vehicle configurations, many different individual contributors, and not yet any clearly dominant technology, there is a great deal of potentially confusing terminology in use:

tilt, lean, and roll are all used somewhat interchangeably, depending on the context and the writer, usually to mean rotation about a longitudinal axis of the vehicle.
stable and stability are usually used in this context to characterize whether the vehicle tilts, leans, or rolls as the rider wishes. As with directional stability, a vehicle is considered stable about its longitudinal axis if it returns to the vertical/ straight orientation hands free, and unstable if it does not. The stability of a vehicle may vary with its forward speed, and the stability might be inherent in the vehicle or created by the rider or some other active controller. For example, bicycles exhibit no stability when stationary, they simply fall over, but can exhibit self-stability if rolling forward at the right speed, even without a rider. Meanwhile, active tilters exhibit roll stability at all times and are designed not to rollover in a turn. Tilting vehicles may exhibit nearly any combination of the above behaviors, due to any combination of their geometry, mass distribution, suspension characteristics, rider input, or some other active control system.
active, passive, and free usually refer to how the tilt angle is controlled, directly or indirectly. "Active" control usually requires some sensor(s), some capacity to calculate a response, such as a feedback controller, and some actuator(s) that require power sources. "Passive" control and "free" control mean there are no sensors, comparisons, response calculation, or actuators and the vehicle is controlled as a bicycle or motorcycle ^[1] "Free" and "passive" usually mean that the vehicle tilts as a bicycle or motorcycle, and the rider must control the tilt angle indirectly by steering the vehicle.

direct and indirect usually refer to how active control is applied. The rider on a "free-tilting" and "passive-tilting" trike usually can apply a steer torque directly, which then controls the tilt angle indirectly, as on bicycles and motorcycles. The rider on a "free-to-caster" trike, on the other hand, can apply a roll torque directly, which then controls the steer angle indirectly.
highside and lowside are expressions already commonly used in the motorcycle world to describe ways in which the bodies of these vehicles may collide with the ground.

Benefits and drawbacks

The potential benefits of tilting, compared to the rigid alternative, include:

The ability to balance the moment caused by lateral acceleration in a turn, due to high speed, tight radius, or both, with a counter moment caused by gravity, means these vehicles do not have to be low, wide, and/or slow. Also, since stability no longer depends on the axle track, the center of mass does not have to be located near the wide axle and instead can be located anywhere between the front and rear axle to optimize other performance characteristics such as ride quality or braking performance.
Leaning into a turn, as bicycles and motorcycles do, means that the net acceleration experienced by the vehicle and rider can always be aligned with the midplane of the vehicle. Riders may find this more pleasant than the alternative, and vehicle components, such as the frame, wheels, and tires, can avoid large side loads.
A narrow axle track means that the vehicle does not require as much pavement and may experience less aerodynamic drag because of a smaller cross-sectional area.
Depending on how the tilting is implemented, a tilting vehicle can be oriented independent of cross slope, such as from the crown in a road or a soft shoulder.

The drawbacks of tilting, compared to the rigid alternative, include:

The tilting mechanism, free or controlled, requires more constructive elements compared to two-wheeled (motor-) cycles, while independent suspension of rigid three-wheelers may be more complex
Control of the tilting either requires some kind of automated control system or different behavior from the rider, such as countersteering.

Configurations

Wheel layout

As with tricycles in general, the two main wheel layouts are:

delta, with one wheel in front and two wheels in back. Notable examples include the Ariel 3, MEV Tilting Trike, Honda Canopy, Vandenbrink Carver, and CLEVER.
tadpole, with two wheels in front and one wheel in back. Notable examples include the TVA Tilting Vehicle Australia 3 & 4 wheel versionsTilting car, Piaggio MP3, Yamaha Tricity, and Toyota i-Road.

Twinned Wheel Rule: In many countries aligned to EU regulations, an arrangement of two wheels on the same axle [not necessarily maintained co-axial], is treated as one wheel provided they are spaced no further apart than 460 mm (18 in) between contact patch centers. This has the effect of allowing vehicles complying with this dimensional limit to be classified as motorcycles. Therefore, such vehicles would be subject to all the technical prescriptions applicable to motorcycles rather than motorised tricycles or four-wheeled vehicles.^[2]

Steered wheels

Rear-wheel steering tends to be directionally unstable, and so the vast majority of trikes employ front-wheel steering.^[3] A notable exception is the Toyota i-Road.^[4] In the case of two wheel steering, some accommodation is usually made to account for the different radii of their paths, such as Ackermann steering geometry.

Driven wheels

Either the front or rear wheel(s) may be driven, but driving a wheel near its power source is usually simpler than driving a wheel at the other end of the vehicle, driving a single wheel is usually simpler than driving a pair of wheels, and driving a wheel that remains aligned with its power source is simpler than driving a wheel that tilts or steers relative to its power source. Two common drive configurations are:

Drive two non-tilting wheels in the rear. Notable examples include the Ariel 3, MEV Tilting Trike, Honda Canopy, Vandenbrink Carver, and CLEVER.
Drive one tilting wheel in the rear. Notable examples include the TVA Tilting Vehicle Australia 3 wheel version Tilting car, Piaggio MP3, Yamaha Tricity, and Toyota i-Road.

Less common drive configurations include:

Drive two tilting wheels in the rear.^[5]
Drive one tilting wheel in the front. One example is the Rose-Hulman Ragnarök pictured below.

Seating

As with tricycles in general, seating may be upright, as on the Piaggio MP3, or recumbent, as on the MEV Tilting Trike. If the vehicle is designed to accommodate a second rider, the seating is usually arranged in tandem to maintain the narrow profile, as on the CLEVER.

Enclosure

The rider may be fully exposed, as on the Tripendo, behind a fairing or windscreen, as on the Piaggio MP3, under a canopy, as on the Honda Canopy, or fully enclosed, as on the Vandenbrink Carver.

Power

Power may come from the rider, as on the Tripendo, from batteries and electric motors, as on the Toyota i-Road, or from conventional internal combustion engines, as on the Yamaha Tricity.

Tilting

Any number of the wheels can tilt, and advantages to tilting wheels are that the wheels do not need to bear large side loads,^[6] and the tires mounted on them can generate camber thrust, which can reduce the need for a slip angle to generate cornering force.^[7] Configurations include:

One wheel in front and only the front tilts, referred to as 1F1T (i.e. one front one tilts). Notable examples include the Ariel 3, MEV Tilting Trike, Honda Canopy, Vandenbrink Carver, and CLEVER.
One wheel in front and all three wheels tilt, referred to as 1F3T (i.e. one front three tilt). An example can be seen in the Rose-Hulman Ragnarök pictured below and the UWM PantherTrike pictured above.
Two wheels in front and only the single rear wheel tilts, referred to as 2F1T (i.e. two front one tilt).^[8]
Two wheels in front and all three wheels tilt, referred to as 2F3T (i.e. two front three tilt). Notable examples include the TVA Tilting Vehicle Australia (James FTC vehicle) 3 wheel version Tilting car, Piaggio MP3, Yamaha Tricity, and Toyota i-Road.

In the case where the two side-by-side wheels tilt, some mechanical linkage is necessary to coordinate their tilting. Implementations include:

Some form of one or more parallelograms, such as on the Tripendo pictured above and the Mercedes-Benz F300 Life Jet Concept Vehicle pictured below. This has been employed on tadpole and delta trike configurations.
Some form a pair of swingarms, possibly connected by some form of bell crank.^[9] This tends to be employed on delta trike configurations.
Some form of crank, in which case the two wheels are not directly side-by-side.^[6] This tends to be employed on delta trike configurations.
Some form of coordination between parallel telescopic forks, as on the Yamaha MWT-9 pictured above and the Yamaha Niken pictured below.

Due to the tilting, there is not necessarily any side-to-side load transfer between the wheels in cornering, so the rule of thumb about tadpoles understeering and deltas oversteering does not necessarily apply.^[10] If the tilting mechanism has some limitation on tilt angle, then the lateral acceleration the vehicle can experience without rolling over will be a function of maximum tilt angle possible, axle track, and center of mass location.^[10]

Free, passive, or active tilt control

Free tilting and passive tilting vehicles are controlled as with a bicycle or motorcycle, in which case countersteering is required.^[11] Actively controlled tilters are where the rider or some other controller actively sets the tilt angle directly.^[12] Vehicles for which the rider has direct control over the tilt angle include the General Motors Lean Machine, in which the rider controlled tilt with foot pedals,^[13] and the Tripendo, in which the rider controls tilt by hand with a lever.^[14] An active controller may calculate a desired tilt angle from some combination of lateral acceleration and steering input, and it may set a desired tilt angle with some combination of mechanical, electrical, or hydraulic actuators.^[15]

Free-tilting/ passive -tilting vehicles possess no stability about their roll axis when stationary. To remedy this problem some free/ passive tilters use tilt locks or restraints when at low speeds. Some use a brake applied to the tilting mechanism, some use progressive roll stability adjustments. Free/passive tilters possess self stability when moving forward with sufficient traction, as with bicycles and motorcycles, and if traction is lost the vehicle will likely lowside.^[12] The lateral spacing of the wheels does not avoid tipping over, these vehicles behave and are controlled like single track vehicles.
Active tilt vehicles such as the James FTC (Free To Castor) uses the geometry of the suspension/steering system to control the vehicle directional path ^[16]
Active-tilt vehicles are designed to possess roll stability at all times when stopped or in motion, and if traction is lost, the vehicles will not lowside.^[15] In these vehicles the lateral spacing of the wheel set is put to effective use to create additional stability.

In all cases, the tilting mechanism may simply be lockable to facilitate keeping the vehicle upright when stopped or parked.^[17] Also, passive or active tilting systems cannot simply counter the roll moment caused by gravity, as this has been shown to make a vehicle practically unsteerable,^[18] although there is ongoing debate about whether it is truly unsteerable or not.^[18]

Enclosures

Enclosures can protect rider(s) from the weather and allow for reduced aerodynamic drag.

Unenclosed vehicles may employ free or passive tilt control because the rider can still put a foot down when stopped. The rider is responsible for controlling tilt just as they would on a two-wheeled bicycle or motorcycle.
Enclosed vehicles, in which the rider cannot reach the ground, must provide come kind of active tilt control, either automatic or by the rider, to keep the vehicle upright when stopped.

Steering

Steering requires that the axle(s) of the front wheel(s) form a finite angle with the axle(s) of the rear wheel(s), i.e. not be parallel. This misalignment may be accomplished in a variety of ways, and usually the front wheel(s) rotate about a steering axis relative to the rest of the vehicle and the rear wheel(s). One notable exception, already mentioned above, is the rear-wheel-steered Toyota i-Road.^[4]

Countersteering

Some Tilting trikes are forced-tilted, such as the Carver, where the countersteering is not controlled by the operator. Some versions of the model introduced automatic countersteer to increase tilt speed and reduce the force required to tilt the vehicle. Other forced-tilted vehicles may incorporate automatic countersteering.^[19] A prototype tilting multi-track free leaning vehicle was developed in 1984 that employs automatic countersteering and does not require any balancing skills.^[20]

A larger range of tilting three-wheelers has appeared in the recent years and use manually controlled countersteering like a motorbike, such as the Piaggio MP3 or Yamaha Niken.

Free to castor

One vehicle variation is to control the steered wheel(s) indirectly by tilting them, along with the vehicle body, and this system is known as free to castor [FTC]. The directional control of a FTC wheel is not particularly strong, as demonstrated by the wheels on a shopping cart, and the castored wheel(s) will turn due to any applied side loading. If the steering axis is not vertical, however, the directional stability above about 10 mph (16 km/h) is very strongly controlled by the dynamic forces. If the castored wheel is attached to the front of a narrow tilting vehicle the castor will automatically place itself on the correct steer angle for the tilt and the speed of the vehicle. A system can be used below 10 mph (16 km/h) to improve slow-speed performance where the steerable wheel(s) are progressively captured to the vehicle tilt action as vehicle speed decreases.^[21]

Examples

Ariel 3 from 1970. (1F1T)
MEV Tilting Trike, patented in 2005. (1F1T)
Honda Canopy used for delivery service (1F1T)
CLEVER prototype without bodywork, June 2013. (1F1T)
Flevotrike (1F1T)
Rose-Hulman Ragnarök (1F3T)
SynergEthic Tilter (1F3T)
University of Wisconsin-Milwaukee narrow-track, tilting, recumbent trike (1F3T)
Toyota i-Road (2F3T)
Yamaha Tricity (2F3T)
Piaggio MP3 (2F3T)
Piaggio MP3 (2F3T) with roof and wagon
Gilera Fuoco (2F3T)
Peugeot Metropolis 400i (2F3T)
Quadro 350D [ de ] (2F3T)
Mercedes-Benz F300 Life Jet Concept Vehicle, 1997. (2F3T)
2018 Yamaha Niken. (2F3T)

Related Research Articles

An anti-lock braking system (ABS) is a safety anti-skid braking system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses. ABS operates by preventing the wheels from locking up during braking, thereby maintaining tractive contact with the road surface and allowing the driver to maintain more control over the vehicle.

<span class="mw-page-title-main">Recumbent bicycle</span> Type of bicycle

A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position. Some recumbent riders may choose this type of design for ergonomic reasons: the rider's weight is distributed comfortably over a larger area, supported by back and buttocks. On a traditional upright bicycle, the body weight rests entirely on a small portion of the sitting bones, the feet, and the hands.

<span class="mw-page-title-main">Tricycle</span> Three-wheeled self-powered vehicle

A tricycle, sometimes abbreviated to trike, is a human-powered three-wheeled vehicle.

Steering is the control of the direction of locomotion or the components that enable its control. Steering is achieved through various arrangements, among them ailerons for airplanes, rudders for boats, tilting rotors for helicopters, and many more.

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 vehicles, the front and rear wheel usually follow slightly different paths when turning or when out of alignment.

Suspension is the system of tires, tire air, springs, shock absorbers and linkages that connects a vehicle to its wheels and allows relative motion between the two. Suspension systems must support both road holding/handling and ride quality, which are at odds with each other. The tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the road or ground forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different.

The caster angle or castor angle is the angular displacement of the steering axis from the vertical axis of a steered wheel in a car, motorcycle, bicycle, other vehicle or a vessel, as seen from the side of the vehicle. The steering axis in a car with dual ball joint suspension is an imaginary line that runs through the center of the upper ball joint to the center of the lower ball joint, or through the center of the kingpin for vehicles having a kingpin.

<span class="mw-page-title-main">Countersteering</span> Single-track vehicle steering technique

Countersteering is used by single-track vehicle operators, such as cyclists and motorcyclists, to initiate a turn toward a given direction by momentarily steering counter to the desired direction. To negotiate a turn successfully, the combined center of mass of the rider and the single-track vehicle must first be leaned in the direction of the turn, and steering briefly in the opposite direction causes that lean. The rider's action of countersteering is sometimes referred to as "giving a steering command".

A three-wheeler is a vehicle with three wheels. Some are motorized tricycles, which may be legally classed as motorcycles, while others are tricycles without a motor, some of which are human-powered vehicles and animal-powered vehicles.

Carver Europe B.V. is a Dutch company that develops and manufactures three-wheeled electric enclosed man-wide vehicles. The company's core technology is the Dynamic Vehicle Control (DVC) system, which enables narrow vehicles to make banked turns, aiding stability when turning at high speeds.

The CLEVER is a type of tilting three-wheeled motor vehicle that was developed in a collaboration between the University of Bath, BMW and a number of other partners from across Europe. CLEVER is designed as an alternative to conventional means of personal urban transport. The narrow body endows it with some of the manoeuvrability and congestion avoiding capability of a motorcycle, whilst offering comparable weather and impact protection to a car. Carbon emissions are reduced as a function of low weight and a small frontal area. The narrow track width requires that CLEVER tilts into corners to maintain stability; thus it is fitted with a Direct Tilt Control (DTC) system that uses hydraulic actuators linking the cabin to the non-tilting rear engine module.

<span class="mw-page-title-main">Bicycle and motorcycle dynamics</span> Science behind the motion of bicycles and motorcycles

Bicycle and motorcycle dynamics is the science of the motion of bicycles and motorcycles and their components, due to the forces acting on them. Dynamics falls under a branch of physics known as classical mechanics. Bike motions of interest include balancing, steering, braking, accelerating, suspension activation, and vibration. The study of these motions began in the late 19th century and continues today.

<span class="mw-page-title-main">Piaggio MP3</span> Type of motorcycle

The Piaggio MP3 is a tilting three-wheeled scooter by Italian manufacturer Piaggio. First marketed in 2006, it is noted for its combination of two front wheels and a single rear wheel.

Bicycle and motorcycle geometry is the collection of key measurements that define a particular bike configuration. Primary among these are wheelbase, steering axis angle, fork offset, and trail. These parameters have a major influence on how a bike handles.

A scooter is a motorcycle with an underbone or step-through frame, a seat, a transmission that shifts without the operator having to operate a clutch lever, a platform for the rider's feet, and with a method of operation that emphasizes comfort and fuel economy. Elements of scooter design were present in some of the earliest motorcycles, and motor scooters have been made since at least 1914. More recently, scooters have evolved to include scooters exceeding 250cc classified as Maxi-scooters.

<span class="mw-page-title-main">Motorized tricycle</span> Resembling a bicycle with two rear wheels and an engine

A motorized tricycle, motor trike, or motortrycle is a three-wheeled vehicle based on the same technology as a bicycle or motorcycle, and powered by an electric motor, motorcycle, scooter or car engine.

The Yamaha Tricity is a tilting three-wheeler motor scooter made by Yamaha Motor Company. It is part of Yamaha's LMW offering along with the Niken.

A narrow-track vehicle is a vehicle that leaves a narrow ground track as it moves forward. Narrow-track vehicles may have lateral stability when stationary but usually lean into turns to prevent falling towards the outside.

The Yamaha Niken is a 845 cc tilting three-wheeler motorcycle, manufactured since 2018 by Yamaha Motor and sold worldwide.

References

↑ Jignesh Sindha; Basab Chakraborty; Debashish Chakravarty (February 7, 2017). "Automatic stability control of three-wheeler vehicles – recent developments and concerns towards a sustainable technology". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 232 (3): 418–434. doi:10.1177/0954407017701285. S2CID 115787151. Passive tilt control. The 3Ws with an additional degree of freedom that allows the driver to tilt the vehicle during turning are categorised as passive tilt-controlled 3Ws. Active tilt control. Real-time computation of cornering force and gravitational force, acting at the CG, needs to be carried out to evaluate the required tilt angle during the automatic control of actuators.
↑ "Proposal for amendments to the Consolidated Resolution on the construction of vehicles" (PDF). UN Economic Commission for Europe. January 8, 2019. Retrieved 2019-12-16. "Twinned wheels" means two wheels positioned on the same axle, which are considered to be one wheel, whereby the distance between the centres of the areas of contact with the ground is equal to, or less than 460 mm.
↑ Timothy Smith (January 30, 2009). "This a description of how to build a Rear Wheel Steering Front Wheel Drive Trike". International Human Powered Vehicle Association . Retrieved 2018-10-27. Sharp steering movements throws your weight with the turn and upsets the stability of the trike.
1 2 Alex Davies (November 13, 2015). "The Funky Toyota i-Road Is Like Nothing I've Ever Driven". Wired . Retrieved 2019-12-16. At slow speeds, the single rear wheel does the steering.
↑ Edelmann; Plöchl; Lugner (May 18, 2011). "Modelling and analysis of the dynamics of a tilting three-wheeled vehicle". Multibody System Dynamics. 26 (4): 469–487. doi:10.1007/s11044-011-9258-7. S2CID 119512934 . Retrieved 2018-11-15.
1 2 Stephen Nurse; Mark Richardson; Robbie Napper (September 2015). "Tilting Human Powered Trikes: Principles, Designs and New Developments". Australasian Transport Research Forum. Retrieved 2018-10-18.
↑ Dan Roe (November 4, 2016). "This Professor's Bike Experiments Might Change the Way You Ride". Bicycling . Retrieved 2018-11-05. Camber thrust is the ability of a tire to generate force when leaned over during a turn.
↑ Sahil; Oza; Malankiya (2015). "Design and Stability of Recumbent Tricycle" . Retrieved 2018-11-02.
↑ Ben Coxworth (March 11, 2011). "Deliver-E Trike quietly takes on uneven ground". New Atlas. Retrieved 2018-10-27.
1 2 Robert Q. Riley; Tony Foale (2018-07-23). "The Dynamic Stability of Three-Wheeled Vehicles in Automotive-Type Applications". Robert Q. Riley Enterprises. Retrieved 2018-11-05. The single front wheel layout naturally oversteers and the single rear wheel layout naturally understeers.
↑ James Robertson (February 2014). "Active Control of Narrow Tilting Vehicle Dynamics (PhD Thesis)" (PDF). University of Bath . Retrieved 2019-12-26. as is the case with passive tilt control, an additional stabilisation mechanism is required at very low speeds and when stationary.
1 2 Berote; van Poelgeest; Darling; Edge; Plummer (2014). "The Dynamics of a Three-Wheeled Narrow-Track Tilting Vehicle" . Retrieved 2018-11-02.
↑ "General Motors Lean Machine". Small Cars Club. May 21, 2017. Retrieved 2019-07-13.
↑ Craig J. Cornelius (November 29, 2018). "Aerion: An Optimized All-weather Ped-electric Trycicle" . Retrieved 2018-11-02.
1 2 Adrian Padeanu (May 2, 2018). "An A-Class-powered three-wheeler with RWD and a body that leaned into bends". Motor1.com. Retrieved 2018-10-27.
↑ Philip James (Nov 23, 2019). "Dynamic analysis and control of narrow track vehicles via a multibody modeling approach" . Retrieved 2020-11-23.
↑ Adam Ruggiero (March 18, 2015). "Future Of Human Powered Transport Is A Trike". GearJunkie. Retrieved 2018-10-27.
1 2 O. Dong; C. Graham; A. Grewal; C. Parrucci; A. Ruina (September 30, 2014). "A bicycle in zero gravity can be balanced or steered but not both" (PDF). Vehicle System Dynamics. 52 (12): 1681. Bibcode:2014VSD....52.1681D. doi:10.1080/00423114.2014.956126. S2CID 17873675 . Retrieved 2018-11-06. [Note, the uncontrollability at zero gravity is only true for the linearized inverted pendulum. The arguments precluding control are heavily dependent on the linearity of the system, and the non-linear inverted pendulum in zero gravity seems to be controllable. Indeed, simulations by Philip James ... demonstrate that with appropriate wiggles of the base, a constant average acceleration of the base can be maintained while holding the pendulum angle in a bounded range.]
↑ Poelgeest, A; Edge, K. A.; Darling, J. (November 2007). Development of a Steer Tilt Controller for a Three Wheeled Tilting Vehicle.
↑ Mike McCarthy (January 1987). "Bankable future for leaning car". Wheels Magazine. pp. 12–13. Retrieved 2014-11-18.
↑ Jeffrey Too Chuan TAN; et al. (2016). "Steering Dynamics of Tilting Narrow Track Vehicle with Passive Front Wheel Design". Journal of Physics: Conference Series. 744 (1): 012218. Bibcode:2016JPhCS.744a2218T. doi: 10.1088/1742-6596/744/1/012218 .

Bibliography

Poelgeest, A., Edge, K. A. and Darling, J., 2007. Development of a Steer Tilt Controller for a Three Wheeled Tilting Vehicle. In: ASME International Mechanical Engineering Congress and Exposition, 2007-11-01, Seattle, Washington.
Tilting Three Wheelers - Patents
The Design, Implementation and Analysis of Motorized Tilting Three-Wheelers. Thesis, Choa-Chin Weng. 18 July 2005. Chinese. English abstract.
Dynamic Stability of Three-Wheeled Vehicles in Automotive-Type Applications. Robert Q. Riley.
Carver One

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[1] Jignesh Sindha; Basab Chakraborty; Debashish Chakravarty (February 7, 2017). "Automatic stability control of three-wheeler vehicles – recent developments and concerns towards a sustainable technology". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 232 (3): 418–434. doi:10.1177/0954407017701285. S2CID 115787151. Passive tilt control. The 3Ws with an additional degree of freedom that allows the driver to tilt the vehicle during turning are categorised as passive tilt-controlled 3Ws. Active tilt control. Real-time computation of cornering force and gravitational force, acting at the CG, needs to be carried out to evaluate the required tilt angle during the automatic control of actuators.

[2] "Proposal for amendments to the Consolidated Resolution on the construction of vehicles" (PDF). UN Economic Commission for Europe. January 8, 2019. Retrieved 2019-12-16. "Twinned wheels" means two wheels positioned on the same axle, which are considered to be one wheel, whereby the distance between the centres of the areas of contact with the ground is equal to, or less than 460 mm.

[3] Timothy Smith (January 30, 2009). "This a description of how to build a Rear Wheel Steering Front Wheel Drive Trike". International Human Powered Vehicle Association . Retrieved 2018-10-27. Sharp steering movements throws your weight with the turn and upsets the stability of the trike.

[Davies-4] 1 2 Alex Davies (November 13, 2015). "The Funky Toyota i-Road Is Like Nothing I've Ever Driven". Wired . Retrieved 2019-12-16. At slow speeds, the single rear wheel does the steering.

[5] Edelmann; Plöchl; Lugner (May 18, 2011). "Modelling and analysis of the dynamics of a tilting three-wheeled vehicle". Multibody System Dynamics. 26 (4): 469–487. doi:10.1007/s11044-011-9258-7. S2CID 119512934 . Retrieved 2018-11-15.

[Nurse-6] 1 2 Stephen Nurse; Mark Richardson; Robbie Napper (September 2015). "Tilting Human Powered Trikes: Principles, Designs and New Developments". Australasian Transport Research Forum. Retrieved 2018-10-18.

[7] Dan Roe (November 4, 2016). "This Professor's Bike Experiments Might Change the Way You Ride". Bicycling . Retrieved 2018-11-05. Camber thrust is the ability of a tire to generate force when leaned over during a turn.

[8] Sahil; Oza; Malankiya (2015). "Design and Stability of Recumbent Tricycle" . Retrieved 2018-11-02.

[9] Ben Coxworth (March 11, 2011). "Deliver-E Trike quietly takes on uneven ground". New Atlas. Retrieved 2018-10-27.

[Riley&Foale-10] 1 2 Robert Q. Riley; Tony Foale (2018-07-23). "The Dynamic Stability of Three-Wheeled Vehicles in Automotive-Type Applications". Robert Q. Riley Enterprises. Retrieved 2018-11-05. The single front wheel layout naturally oversteers and the single rear wheel layout naturally understeers.

[11] James Robertson (February 2014). "Active Control of Narrow Tilting Vehicle Dynamics (PhD Thesis)" (PDF). University of Bath . Retrieved 2019-12-26. as is the case with passive tilt control, an additional stabilisation mechanism is required at very low speeds and when stationary.

[Berote-12] 1 2 Berote; van Poelgeest; Darling; Edge; Plummer (2014). "The Dynamics of a Three-Wheeled Narrow-Track Tilting Vehicle" . Retrieved 2018-11-02.

[13] "General Motors Lean Machine". Small Cars Club. May 21, 2017. Retrieved 2019-07-13.

[14] Craig J. Cornelius (November 29, 2018). "Aerion: An Optimized All-weather Ped-electric Trycicle" . Retrieved 2018-11-02.

[Padeanu-15] 1 2 Adrian Padeanu (May 2, 2018). "An A-Class-powered three-wheeler with RWD and a body that leaned into bends". Motor1.com. Retrieved 2018-10-27.

[James_FTC-16] Philip James (Nov 23, 2019). "Dynamic analysis and control of narrow track vehicles via a multibody modeling approach" . Retrieved 2020-11-23.

[17] Adam Ruggiero (March 18, 2015). "Future Of Human Powered Transport Is A Trike". GearJunkie. Retrieved 2018-10-27.

[Ruina-18] 1 2 O. Dong; C. Graham; A. Grewal; C. Parrucci; A. Ruina (September 30, 2014). "A bicycle in zero gravity can be balanced or steered but not both" (PDF). Vehicle System Dynamics. 52 (12): 1681. Bibcode:2014VSD....52.1681D. doi:10.1080/00423114.2014.956126. S2CID 17873675 . Retrieved 2018-11-06. [Note, the uncontrollability at zero gravity is only true for the linearized inverted pendulum. The arguments precluding control are heavily dependent on the linearity of the system, and the non-linear inverted pendulum in zero gravity seems to be controllable. Indeed, simulations by Philip James ... demonstrate that with appropriate wiggles of the base, a constant average acceleration of the base can be maintained while holding the pendulum angle in a bounded range.]

[19] Poelgeest, A; Edge, K. A.; Darling, J. (November 2007). Development of a Steer Tilt Controller for a Three Wheeled Tilting Vehicle.

[20] Mike McCarthy (January 1987). "Bankable future for leaning car". Wheels Magazine. pp. 12–13. Retrieved 2014-11-18.

[21] Jeffrey Too Chuan TAN; et al. (2016). "Steering Dynamics of Tilting Narrow Track Vehicle with Passive Front Wheel Design". Journal of Physics: Conference Series. 744 (1): 012218. Bibcode:2016JPhCS.744a2218T. doi: 10.1088/1742-6596/744/1/012218 .

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]