Road-holding – also written as roadholding and road holding – (in French being called "tenue de route", in German "Beibehaltung der Spur"), is essentially determined by the ability of a

vehicle A vehicle () is a machine designed for self-propulsion, usually to transport people, cargo, or both. The term "vehicle" typically refers to land vehicles such as human-powered land vehicle, human-powered vehicles (e.g. bicycles, tricycles, velo ...

to stay on the

road A road is a thoroughfare used primarily for movement of traffic. Roads differ from streets, whose primary use is local access. They also differ from stroads, which combine the features of streets and roads. Most modern roads are paved. Th ...

and on a desired

trajectory A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete tra ...

motion In physics, motion is when an object changes its position with respect to a reference point in a given time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed, and frame of reference to an o ...

, whatever the circumstances (in curves, on greasy, wet or low-grip ground, loaded or not, etc.) may be, but also by the degree of ease that a driver may sense in controlling it in an

emergency An emergency is an urgent, unexpected, and usually dangerous situation that poses an immediate risk to health, life, property, or environment and requires immediate action. Most emergencies require urgent intervention to prevent a worsening ...

situation. (Hereby, the laws of nature as a framework, including the

gravitation In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...

al field of the planet

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

as well as the phenomenon of

inertia Inertia is the natural tendency of objects in motion to stay in motion and objects at rest to stay at rest, unless a force causes the velocity to change. It is one of the fundamental principles in classical physics, and described by Isaac Newto ...

, are tacitly assumed as given.) In the above context, the straight-line stability of a vehicle – which is concomitant with its ability to stay on a desired trajectory of motion – necessitates a certain degree of understeering. The capability to smooth down the road imperfections, affects both the

comfort Comfort is a state of physical or psychological ease, often characterized by the absence of hardship. Individuals experiencing a lack of comfort are typically described as uncomfortable or in discomfort. A degree of psychological comfort can b ...

and the road-holding of a vehicle. To improve comfort in this regard means, basically, to limit the vertical

acceleration In mechanics, acceleration is the Rate (mathematics), rate of change of the velocity of an object with respect to time. Acceleration is one of several components of kinematics, the study of motion. Accelerations are Euclidean vector, vector ...

fluctuations of the vehicle body and hence of passengers. To improve road-holding means, among other things, to limit the fluctuations of the vertical force that each

tire A tire (North American English) or tyre (Commonwealth 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 (engineeri ...

exchanges with the road. Therefore, modeling and

simulation A simulation is an imitative representation of a process or system that could exist in the real world. In this broad sense, simulation can often be used interchangeably with model. Sometimes a clear distinction between the two terms is made, in ...

using realistic suspension-

damping In physical systems, damping is the loss of energy of an oscillating system by dissipation. Damping is an influence within or upon an oscillatory system that has the effect of reducing or preventing its oscillation. Examples of damping include ...

models, taking the vehicle tires into account, offer a straightforward opportunity for road-holding improvement of vehicles. Optimization techniques for this purpose are also known. The application of inerters is a very new possibility in this regard, although this

technology Technology is the application of Conceptual model, conceptual knowledge to achieve practical goals, especially in a reproducible way. The word ''technology'' can also mean the products resulting from such efforts, including both tangible too ...

is more destined to

race car Race, RACE or The Race may refer to: * Race (biology), an informal taxonomic classification within a species, generally within a sub-species * Race (human categorization), classification of humans into groups based on physical traits, and/or s ...

s than to ordinary vehicle applications. As a more sophisticated means for improving road-holding,

active suspension An active suspension is a type of Suspension (vehicle), automotive suspension that uses an onboard control system to control the vertical movement of the vehicle's wheels and axles relative to the chassis or vehicle frame, rather than the conventi ...

– involving

sensor A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

actuator An actuator is a machine element, component of a machine that produces force, torque, or Displacement (geometry), displacement, when an electrical, Pneumatics, pneumatic or Hydraulic fluid, hydraulic input is supplied to it in a system (called an ...

s and

microcontroller A microcontroller (MC, uC, or μC) or microcontroller unit (MCU) is a small computer on a single integrated circuit. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Pro ...

s – may also serve. For vehicle speeds above approximately 40 meters per second, the effects of

aerodynamic force In fluid mechanics, an aerodynamic force is a force exerted on a body by the air (or other gas) in which the body is immersed, and is due to the relative motion between the body and the gas. Force There are two causes of aerodynamic force: * ...

s at an

automobile A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...

(that is not designed in a too odd manner) tend to become sensible for its road-holding.Doniselli, C. et al.: ''Aerodynamic effects on ride comfort and road holding of automobiles.'' In: ''International Journal of Vehicle Mechanics and Mobility.'' Vol. 25, Issue Suppl. 1, pp. 99-125, 1996. Beyond what has been previously mentioned,

electronic stability control Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a car handling, vehicle's stability by detecting and reducing loss of Tract ...

, if being present on a vehicle and properly tuned, will have a stabilizing influence on the trajectory of motion and accordingly an improving effect on road-holding of that vehicle.

References

Vehicle dynamics

See also

References