Tilting system
CLEVER employs an electronically controlled and hydraulically actuated Direct Tilt Control system with a maximum tilt angle of ±45° [6]. A pair of single acting hydraulic actuators generate a tilting moment about the tilt bearing (which joins the cabin and rear module). The tilt controller uses driver's steer input and the vehicle's speed to estimate the lateral acceleration and hence the appropriate tilt angle. The DTC system provides excellent stability at low speeds but during vigorous manoeuvres at higher speeds the system's torque output exceeds that which can be reacted by the non-tilting rear module; as a result the inside rear wheel lifts, this can lead to the vehicle rolling over.
To improve the roll stability in transient conditions, the prototype CLEVER vehicle was fitted with an active steering system in 2012; this allowed the use of a combined Steering Direct Tilt Control (SDTC) strategy. The active steering system output is a function of the vehicle's tilt angle error (the difference between the actual and ideal tilt angle), therefore at steady state when there is little or no tilt angle error the front wheel steer angle matches the driver's steer demand. However, in transient situations, such as upon turn-in, a tilt angle error exists and the active steering system acts to reduce or eliminate the driver's steering input. In extreme conditions it will also initiate a countersteering action whereby the front wheel momentarily steers in the opposite direction to that intended by the driver. As the cabin approaches the desired tilt angle, the magnitude of the tilt angle error is reduced and the front wheel steer angle takes on the value demanded by the driver.
By reducing the severity of the driver's steer inputs, or indeed initiating countersteer, the active steering system delays the onset of lateral acceleration and reduces the moment necessary for the DTC actuators to tilt the cabin of the vehicle into the corner. This reduced tilting moment benefits both vehicle stability and energy consumption. Simulation results show a significant reduction in load transfer across the rear axle. [3] In 2014 experimental results were published showing a 40% reduction in the load transfer across the rear axle during a severe ramp steer manoeuvre conducted at 10 m/s and showing that the combined SDTC strategy became more effective at higher speeds . [4] In the same article, it is noted that the whilst the driver of a SDTC equipped vehicle is subject to an additional under-steer sensation during harsh transient manoeuvres, this does not inhibit his/her ability to control the vehicle's trajectory.
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.
Steering is a system of components, linkages, and other parts that allows a driver to control the direction of a vehicle.
Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a vehicle's stability by detecting and reducing loss of traction (skidding). When ESC detects loss of steering control, it automatically applies the brakes to help steer the vehicle where the driver intends to go. Braking is automatically applied to wheels individually, such as the outer front wheel to counter oversteer, or the inner rear wheel to counter understeer. Some ESC systems also reduce engine power until control is regained. ESC does not improve a vehicle's cornering performance; instead, it helps reduce the chance of the driver losing control of the vehicle.
A traction control system (TCS), also known as ASR, is typically a secondary function of the electronic stability control (ESC) on production motor vehicles, designed to prevent loss of traction of the driven road wheels. TCS is activated when throttle input and engine power and torque transfer are mismatched to the road surface conditions.
A manual transmission (MT), also known as manual gearbox, standard transmission, or stick shift, is a multi-speed motor vehicle transmission system, where gear changes require the driver to manually select the gears by operating a gear stick and clutch.
Automobile handling and vehicle handling are descriptions of the way a wheeled vehicle responds and reacts to the inputs of a driver, as well as how it moves along a track or road. It is commonly judged by how a vehicle performs particularly during cornering, acceleration, and braking as well as on the vehicle's directional stability when moving in steady state condition.
Electronic brakeforce distribution or electronic brakeforce limitation (EBL) is an automobile brake technology that automatically varies the amount of force applied to each of a vehicle's wheels, based on road conditions, speed, loading, etc, thus providing intelligent control of both brake balance and overall brake force. Always coupled with anti-lock braking systems (ABS), EBD can apply more or less braking pressure to each wheel in order to maximize stopping power whilst maintaining vehicular control. Typically, the front end carries more weight and EBD distributes less braking pressure to the rear brakes so the rear brakes do not lock up and cause a skid. In some systems, EBD distributes more braking pressure at the rear brakes during initial brake application before the effects of weight transfer become apparent.
Dynamic steering response (DSR) is a vehicle safety and advanced power steering system that can counteract unstable or difficult steering that may be caused by external forces such as strong crosswinds or uneven roads by giving proper steering assistance from the steering gear. DSR assists the driver by determining the correct steering ratio in a vehicle's power steering system to provide steering corrections to stabilize vehicles and increase safety. The system determines the steering ratio(the amount of turning of the steering wheel to the amount of turning of the vehicle’s wheels) based on factors such as current road conditions and vehicle speed. This system works by having an electric motor attached to the steering gear of a vehicle reducing or increasing the torque needed to steer based on the situation. Thus, less physical input from the driver is required creating a more comfortable driving experience overall.
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".
Drive by wire or DbW technology in the automotive industry is the use of electrical or electro-mechanical systems for performing vehicle functions traditionally achieved by mechanical linkages. Common examples include power steering, electronic throttle control and brake-by-wire. These technologies replace the traditional mechanical control systems with electronic control systems using electromechanical actuators and human–machine interfaces such as pedal and steering feel emulators. Components such as the steering column, intermediate shafts, pumps, hoses, belts, coolers and vacuum servos and master cylinders are eliminated from the vehicle. This is similar to the fly-by-wire systems used widely in the aviation industry. Safety standards for drive-by-wire are specified by the ISO 26262 standard level D.
An anti-roll bar is a part of many automobile suspensions that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects opposite (left/right) wheels together through short lever arms linked by a torsion spring. An anti-roll bar increases the suspension's roll stiffness—its resistance to roll in turns—independent of its spring rate in the vertical direction. The first stabilizer bar patent was awarded to Canadian inventor Stephen Coleman of Fredericton, New Brunswick on April 22, 1919.
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. 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. 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. These types of vehicles have also been described as "man-wide vehicles" (MWV).
Power steering is a system for reducing a driver's effort to turn a steering wheel of a motor vehicle, by using a power source to assist steering.
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.
Automatic parking is an autonomous car-maneuvering system that moves a vehicle from a traffic lane into a parking spot to perform parallel, perpendicular, or angle parking. The automatic parking system aims to enhance the comfort and safety of driving in constrained environments where much attention and experience is required to steer the car. The parking maneuver is achieved by means of coordinated control of the steering angle and speed which takes into account the actual situation in the environment to ensure collision-free motion within the available space.
Brake-by-wire technology in the automotive industry is the ability to control brakes through electronic means. It is widely used in the automotive industry by manufacturers such as Audi, Bosch, Brembo, Hyundai, and many others.
Active steering describes a steering system for a vehicle in which the relationship between the driver’s steer inputs and the angle of the steered road wheels may be continuously and intelligently altered. Whilst active steering systems may be found in agricultural equipment and heavy plant, this article concentrates on the application of active steering in BMW passenger cars.
S-AWC is the brand name of an advanced full-time four-wheel drive system developed by Mitsubishi Motors. The technology, specifically developed for the new 2007 Lancer Evolution, the 2010 Outlander, the 2014 Outlander, the Outlander PHEV and the Eclipse Cross have an advanced version of Mitsubishi Motors' AWC system. Mitsubishi Motors first exhibited S-AWC integration control technology in the Concept-X model at the 39th Tokyo Motor Show in 2005. According to Mitsubishi Motors, "the ultimate embodiment of the company's AWC philosophy is the S-AWC system, a 4WD-based integrated vehicle dynamics control system".
All Wheel Control (AWC) is the brand name of a four-wheel drive (4WD) system developed by Mitsubishi Motors. The system was first incorporated in the 2001 Lancer Evolution VII. Subsequent developments have led to S-AWC (Super All Wheel Control), developed specifically for the new 2007 Lancer Evolution. The system is referred by the company as its unique 4-wheel drive technology umbrella, cultivated through its motor sports activities and long history in rally racing spanning almost half a century.
The BMW i4 is a battery electric compact executive car produced by BMW since 2021. It adopts a five-door liftback body style and is marketed as a four-door coupé. The initial concept version, named BMW i Vision Dynamics, debuted at the 2017 Frankfurt Motor Show. It is the fifth BMW i sub-brand model, and is sold in several variants at different performance levels, including the first battery-electric variant by BMW's motorsport division. The production version was revealed in March 2021 and went on sale in November 2021.
