Drive by wire
Encyclopedia
Drive-by-wire, DbW, by-wire, or x-by-wire technology in the automotive industry replaces the traditional mechanical control system
s with electronic control systems using electromechanical actuators and human-machine interface
s such as pedal and steering feel emulators. Hence, the traditional components such as the steering column
, intermediate shafts, pumps, hoses, belts, coolers and vacuum servo
s and master cylinders are eliminated from the vehicle.
Examples include electronic throttle control
and brake-by-wire
.
(ESC), adaptive cruise control and Lane Assist Systems.
Ergonomics can be improved by the amount of force and range of movement required by the driver and by greater flexibility in the location of controls. This flexibility also significantly expands the number of options for the vehicle's design.
Parking can be made easier with reduced lock-to-lock steering wheel travel as with BMW's Active Steering System, or semi-automatic]] which is available in Ford/Lincoln
vehicles in the US, some Toyota Prius in Japan, Lexus
LS460 models worldwide and newer European Volkswagen
models. Although neither of these are strictly Steer-by-Wire (SbW) because they retain mechanical linkages, they show the capabilities that are possible.
and the Mazda Ryuga
. A rear wheel SbW system by Delphi called Quadrasteer
is used on some pickup trucks but has had limited commercial success.
This is not to be confused with Electric Power Steering.
s, steering wheel
s, or even voice command
s — whatever device that designers could come up with.
Control system
A control system is a device, or set of devices to manage, command, direct or regulate the behavior of other devices or system.There are two common classes of control systems, with many variations and combinations: logic or sequential controls, and feedback or linear controls...
s with electronic control systems using electromechanical actuators and human-machine interface
Human-machine interface
Human-machine interface is the part of the machine that handles the Human-machine interaction- Overview :In complex systems, the human-machine interface is typically computerized. The term Human-computer interface refers to this kind of systems....
s such as pedal and steering feel emulators. Hence, the traditional components such as the steering column
Steering column
The automotive steering column is a device intended primarily for connecting the steering wheel to the steering mechanism or transferring the driver's input torque from the steering wheel.-Secondary functions:...
, intermediate shafts, pumps, hoses, belts, coolers and vacuum servo
Vacuum servo
A vacuum servo is a component used on motor vehicles in their braking system, to provide assistance to the driver by decreasing the braking effort. In the USA it is commonly called a brake booster.-Background:...
s and master cylinders are eliminated from the vehicle.
Examples include electronic throttle control
Electronic throttle control
Electronic throttle control is an automobile technology which severs the mechanical link between the accelerator pedal and the throttle. Most automobiles already use a throttle position sensor to provide input to traction control, antilock brakes, fuel injection, and other systems, but use a...
and brake-by-wire
Brake-by-wire
Drive-by-wire technology in automotive industry replaces the traditional mechanical and hydraulic control systems with electronic control systems using electromechanical actuators and human-machine interfaces such as pedal and steering feel emulators...
.
Advantages
Safety can be improved by providing computer controlled intervention of vehicle controls with systems such as Electronic Stability ControlElectronic Stability Control
Electronic stability control is a computerized technology that may potentially improve the safety of a vehicle's stability by detecting and minimizing skids. When ESC detects loss of steering control, it automatically applies the brakes to help "steer" the vehicle where the driver intends to go...
(ESC), adaptive cruise control and Lane Assist Systems.
Ergonomics can be improved by the amount of force and range of movement required by the driver and by greater flexibility in the location of controls. This flexibility also significantly expands the number of options for the vehicle's design.
Parking can be made easier with reduced lock-to-lock steering wheel travel as with BMW's Active Steering System, or semi-automatic]] which is available in Ford/Lincoln
Lincoln (automobile)
Lincoln is an American luxury vehicle brand of the Ford Motor Company. Lincoln vehicles are sold mostly in North America.-History:The company was founded in August 1915 by Henry M. Leland, one of the founders of Cadillac . During World War I, he left Cadillac which was sold to General Motors...
vehicles in the US, some Toyota Prius in Japan, Lexus
Lexus
is the luxury vehicle division of Japanese automaker Toyota Motor Corporation. First introduced in 1989 in the United States, Lexus is now sold globally and has become Japan's largest-selling make of premium cars. The Lexus marque is marketed in over 70 countries and territories worldwide, and has...
LS460 models worldwide and newer European Volkswagen
Volkswagen
Volkswagen is a German automobile manufacturer and is the original and biggest-selling marque of the Volkswagen Group, which now also owns the Audi, Bentley, Bugatti, Lamborghini, SEAT, and Škoda marques and the truck manufacturer Scania.Volkswagen means "people's car" in German, where it is...
models. Although neither of these are strictly Steer-by-Wire (SbW) because they retain mechanical linkages, they show the capabilities that are possible.
Disadvantages
The cost of DbW systems is often greater than conventional systems. The extra costs stem from greater complexity, development costs and the redundant elements needed to make the system safe. Failures in the control system could theoretically cause a runaway vehicle, although this is no different from the throttle return spring snapping on a traditional mechanical throttle vehicle. The vehicle could still be stopped by turning the ignition off if this occurred. Another disadvantage is that manufacturers often reduce throttle sensitivity in the low-mid throttle range to make the car easier or safer to control - or to protect the drivetrain (gearbox, clutch, etc.) from driver abuse. The feeling to the driver is that the throttle feels less responsive. There are aftermarket electronic kits to increase throttle sensitivity, to re-gain a more direct-feeling relationship between pedal position and throttle valve opening.Steer by Wire
This is currently used in electric forklifts and stockpickers and some tractors http://www.motionsystemdesign.com/Issue/Article/47436/ArticleDraw.aspx. Its implementation in road vehicles is limited by concerns over reliability although it has been demonstrated in several concept vehicles such as ThyssenKrupp Presta Steering's Mercedes-Benz Unimog, General Motors' Hy-wire and SequelGeneral Motors Sequel
The Sequel is a purpose-built hydrogen fuel cell-powered concept car and sport utility vehicle from General Motors, employing the latest generation of HydroGen3 technology developed by Opel. The Sequel uses a "skateboard chassis" in which all relevant drivetrain and 700 bar hydrogen storage...
and the Mazda Ryuga
Mazda Ryuga
The Mazda Ryuga is a concept car introduced by Mazda and partner Ford Motor Company at the 2007 North American International Auto Show in Detroit, Michigan. The car, along with the Mazda Nagare which was introduced at the Greater Los Angeles Auto Show, is an exploratory design study intended to...
. A rear wheel SbW system by Delphi called Quadrasteer
Quadrasteer
Quadrasteer is the name of a 4 wheel steering system developed by Delphi Corporation while under the ownership of General Motors for use in automobiles. It was available as an option on GM's full-size pickup trucks and 2500 suburbans for model years 2002 to 2005, inclusive...
is used on some pickup trucks but has had limited commercial success.
This is not to be confused with Electric Power Steering.
Passenger car state-of-the-art
Electronic fuel injection metering in diesel and gasoline engines is now widely used. Electronic throttle control is also in widespread use for gasoline engine control. Purely electronic brake and steering systems have yet to find widespread application in passenger cars. This is primarily because of the significant safety implications of steering or braking systems without a redundant mechanical backup in case of failure of the DbW system. Although it is technically feasible to address these concerns with multiple redundant electronic systems (as in fly-by-wire systems used by many airliners and military aircraft), the additional cost and service requirements have made these systems commercially uncompetitive to date. Hybrid electric vehicles employ limited electronically controlled regenerative braking, but the standard hydraulic braking system is retained. The growth in sales of hybrid and electric vehicles is likely to become an enabling factor for drive-by-wire systems in the future cars because of the availability of high power electrical supplies required for the new electrical actuators.The future
Some fanciful theories and applications abound as to what the ultimate implications of DbW technology might be. It has been suggested that DbW might allow a car to become completely separate from its controls, meaning that a car of the future might theoretically be controlled by any number of different control systems: push buttons, joystickJoystick
A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks, also known as 'control columns', are the principal control in the cockpit of many civilian and military aircraft, either as a center stick or...
s, steering wheel
Steering wheel
A steering wheel is a type of steering control in vehicles and vessels ....
s, or even voice command
Speech recognition
Speech recognition converts spoken words to text. The term "voice recognition" is sometimes used to refer to recognition systems that must be trained to a particular speaker—as is the case for most desktop recognition software...
s — whatever device that designers could come up with.