Changing the conventional understanding of braking and steering
What is "by-wire technology" that will contribute to the realization of the next generation of automobiles?
By-wire technology is indispensable for the realization of driving assistance and automated driving. Thanks to control by wires (electrical signals), a vehicle's steering wheel, brakes, etc. will no longer need to be in their current form and layout. This article will consider the form of cars in the future due to the adoption of by-wire, and how by-wire will contribute to the realization of driving assistance and automated driving.
What is automotive by-wire technology?
By-wire means that the mechanical mechanism (mechanical link) that was used for movement is eliminated, and instead transmitted by wire (electrical signal). In automobiles, along with driver assistance technology, the use of by-wire for accelerator, brake, and steering operations is progressing.
In addition to throttle-by-wire that is already popular, shift-by-wire and steer-by-wire systems are also being installed in automobiles in recent years.
Throttle-by-Wire
Accelerator throttle-by-wire is now used in most automobiles. A sensor measures the amount that the accelerator pedal was pressed, and an electrical signal is transmitted via a wire harness to the ECU (Electronic Control Unit), to control a motor for opening and closing the engine's throttle valve.
Shift-by-Wire
Shift-by-wire transmission shifts are also utilized in most general vehicles. The process is to read the force applied to the gearshift lever with a sensor, transmit it to the ECU, disengage the transmission clutch, determine which gear it is, and engage the clutch again.
This shift-by-wire technology was first introduced in Formula 1 cars in the 1990s. Until then, F1 drivers, when cornering, etc. had to press the clutch and operate the steering wheel while also changing gears. This required considerable physical strength.
In the middle stages of a race, when concentration and stamina were low, this harsh shifting operation had to be performed, which could lead to accidents. However, with the advent of shift-by-wire, it is said that the clutch release time can be shortened and quicker gear shifting can be performed, greatly increasing the degree of freedom in driving.
Brake-by-Wire
Conventional automobiles have many mechanical links. For example, in brake systems, when the driver steps on the brake pedal, it is connected to a hydraulic mechanism that activates the disc brakes. In addition, in steering systems, when the steering wheel is rotated, it is mechanically transmitted to the steering rack, which changes the direction of the tires. The angle (according to the rotation of the steering wheel) is converted into a large torque by a motor and reduction gear, etc. to control the tires.
In order to mechanically stop the tires rotating at high speed, a booster mechanism amplifies the braking force applied by the driver. The amount of depression of the brake pedal is measured by a sensor, and the amount of operation is calculated by the ECU. An electric signal is transmitted to control the brakes.
Steer-by-Wire
The tires are steered by electrical signals without a mechanical connection between the steering wheel and the tires. This technology is necessary to achieve automated driving because it eliminates the need to turn the steering wheel.
Will by-wire change the form of steering and brakes?
The current position of the brake pedal and steering wheel is laid out in the same place in automobiles. This is because almost all of an automobiles's mechanisms that are invisible to the driver are made in the same way, so the shape of automobiles is almost the same.
However, as mechanical mechanisms become by-wire, the form and position of the steering wheel and brake will also change. Using electrical wiring for mechanical transmission means that the brake does not have to be located at the driver's feet. It will be possible to equip a brake button on the steering wheel where the operation buttons are located these days, thereby eliminating the stress of worrying about a brake pedal near the driver's feet.
So, what will happen to the steering wheel when it is steer-by-wire? It is true that the current round steering wheel is designed to make it easier for the driver to drive. However, as the level of automated driving increases, it may be possible to use something like a game controller for steering. There also is a possibility that the day will come when it will be possible to operate the steering with a smartphone.
Benefits of by-wire
The main advantages of by-wire in automobiles are as follows:
• Improved operability and safety
• Low fuel consumption and weight reduction
• Space-saving
In ADAS (Advanced Driver Assistance Systems), by-wire technology enables the vehicle to detect and avoid danger to the driver, and to increase the accuracy of assistance, such as raising the rotation gear of the steering wheel when parking.
In the future, by-wire production may reduce the number of mechanical components and reduce development costs. Reducing heavy metal parts such as gears and replacing them with general-purpose parts such as sensors, wire harnesses, and motors, will also lead to weight reduction in automobiles. Lighter weight improves fuel efficiency and enables travel for longer distances.
In terms of the interior design of the vehicle as well, the elimination of mechanical mechanisms will free up space for storage and the installation of other control boards. In the transition to fully automated driving, the shape of the steering wheel and brakes can also change, and one day they may disappear completely. Due to the adoption of by-wire, the future may not be far off in which there will be more freedom in the shape of cars.
What will be the shape of cars in the future?
If the steering wheel, brake pedal, and accelerator are eliminated and the task of driving is no longer necessary, it will be possible to create a mobility space that has been dreamed of, for example like a living room on the move, where people can watch movies, spend time with friends, work, etc.
Furthermore, in the future when driverless automated vehicles can be mass-produced, it is conceivable that vehicles will pick you up and take you where you want to go with comfortable driving technology, like autonomous chauffeured services.
The use of software technology is important for by-wire conversion
Software is also important for by-wire steering and braking.
In the case of brake-by-wire, control is performed to optimize the condition of the vehicle affected by braking. In steer-by-wire, control is essential to ensure that the vehicle body, which is affected by the driver's steering operation, is in the best condition.
On slippery roads, it is necessary to coordinate steering and braking. Software is required for advanced control that leads to smooth driving by avoiding under-turning and over-turning according to curves in the road and surface conditions.
In addition, communication and infrastructure technologies that use IoT technology to send driving and travel data to the cloud, data science that analyzes and researches such data, and software development that provides services such as automatic parking and dispatching vehicles using AI, are also expected to progress.
As automobiles become more highly advanced due to by-wire, the barrier between hardware and software will disappear, and the importance of software will increase.
*Information contained in this article is current at the time of data collection. (Published on January 23, 2023)