Tilting three-wheeler

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Vandenbrink Carver (1F1T) Carver one 06011701.jpg
Vandenbrink Carver (1F1T)
Tripendo recumbent tricycle, a tilting three-wheeler (2F3T) TripendoTilted.jpg
Tripendo recumbent tricycle, a tilting three-wheeler (2F3T)
Yamaha Niken from 2018 Yamaha Niken - Mondial de l'Automobile de Paris 2018 - 004.jpg
Yamaha Niken from 2018
UWM PantherTrike, a narrow-track, tilting, recumbent, human-powered trike (1F3T) University of Wisconsin-Milwaukee narrow-track, tilting, recumbent trike at ASME HPVC North 2019.jpg
UWM PantherTrike, a narrow-track, tilting, recumbent, human-powered trike (1F3T)

A tilting three-wheeler, tilting trike, leaning trike, or even just tilter, is a three-wheeled vehicle and usually a narrow-track vehicle whose body and or wheels tilt in the direction of a turn. [1] Such vehicles can corner without rolling over despite having a narrow axle track because they can balance some or all of the roll moment caused by centripetal acceleration with an opposite roll moment caused by gravity, as bicycles and motorcycles do. [1] This also reduces the lateral acceleration experienced by the rider, which some find more comfortable than the alternative. The narrow profile can result in reduced aerodynamic drag and increased fuel efficiency. [2] These types of vehicles have also been described as "man-wide vehicles" (MWV). [2]

Contents

As with tricycles that do not tilt, there are a variety of feasible choices of how the wheels are arranged, which wheels are steered, and which wheels are driven. In addition, there are a variety of feasible choices for which wheels tilt and which do not.

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:

Benefits and drawbacks

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

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

Configurations

Wheel layout

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

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. [4]

Steered wheels

Rear-wheel steering tends to be directionally unstable, and so the vast majority of trikes employ front-wheel steering. [5] A notable exception is the Toyota i-Road. [6] 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:

Less common drive configurations include:


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, [1] and the tires mounted on them can generate camber thrust, which can reduce the need for a slip angle to generate cornering force. [8] Configurations include:

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

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. [11] 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. [11]

Free, passive, or active tilt control

In all cases, the tilting mechanism may simply be lockable to facilitate keeping the vehicle upright when stopped or parked. [18] 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, [19] although there is ongoing debate about whether it is truly unsteerable or not. [19]

Enclosures

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

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. [6]

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. [20] A prototype tilting multi-track free leaning vehicle was developed in 1984 that employs automatic countersteering and does not require any balancing skills. [21]

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. [22]

Examples

See also

Related Research Articles

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<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.

<span class="mw-page-title-main">Steering</span> The control of the direction of motion of vehicles and other objects

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.

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

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.

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

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<span class="mw-page-title-main">CLEVER</span>

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.

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<span class="mw-page-title-main">Handcycle</span>

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<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.

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<span class="mw-page-title-main">Scooter (motorcycle)</span> Low-speed motorcycle

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.

<span class="mw-page-title-main">Yamaha Tricity</span> Type of motorcycle

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.

<span class="mw-page-title-main">Narrow-track vehicle</span>

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.

<span class="mw-page-title-main">Yamaha Niken</span> Three-wheeler motorcycle by Yamaha

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

References

  1. 1 2 3 4 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.
  2. 1 2 Pauwelussen, J.P. (1999). "The dynamic behaviour of man-wide vehicles with an automatic active tilting mechanism". TUDelft . Retrieved 2018-11-12.
  3. 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.
  4. "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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. Sahil; Oza; Malankiya (2015). "Design and Stability of Recumbent Tricycle" . Retrieved 2018-11-02.
  10. Ben Coxworth (March 11, 2011). "Deliver-E Trike quietly takes on uneven ground". New Atlas. Retrieved 2018-10-27.
  11. 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.
  12. 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.
  13. 1 2 Berote; van Poelgeest; Darling; Edge; Plummer (2014). "The Dynamics of a Three-Wheeled Narrow-Track Tilting Vehicle" . Retrieved 2018-11-02.
  14. "General Motors Lean Machine". Small Cars Club. May 21, 2017. Retrieved 2019-07-13.
  15. Craig J. Cornelius (November 29, 2018). "Aerion: An Optimized All-weather Ped-electric Trycicle" . Retrieved 2018-11-02.
  16. 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.
  17. Philip James (Nov 23, 2019). "Dynamic analysis and control of narrow track vehicles via a multibody modeling approach" . Retrieved 2020-11-23.
  18. Adam Ruggiero (March 18, 2015). "Future Of Human Powered Transport Is A Trike". GearJunkie. Retrieved 2018-10-27.
  19. 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.]
  20. Poelgeest, A; Edge, K. A.; Darling, J. (November 2007). Development of a Steer Tilt Controller for a Three Wheeled Tilting Vehicle.
  21. Mike McCarthy (January 1987). "Bankable future for leaning car". Wheels Magazine. pp. 12–13. Retrieved 2014-11-18.
  22. 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