Car Tech 101: The coming revolution in drive-by-wire cars: CNET On Cars
CNET On Cars: Car Tech 101: The coming revolution in drive-by-wire cars4:45 /
Drive-by-wire is more than a technology trend, it's also a major shift in the concept of what it means to have control over your cars. Brian Cooley explains.
[MUSIC] Now, the basic concept behind Drive by Wire, which is also known as X by Wire sometimes, is to replace all these physical controls in the vehicle like steering, braking, and accelerator which are mechanical now, with systems that are electronic or electromechanical. Getting rid of the physical linkages. And inserting a computer between you and the vehicle's drive system. Get into your vehicle. Now hit the accelerator pedal. You're not pulling a throttle cable to a carburetor or fuel injector system anymore. You're telling a computer what to do. How bout a shifter in a lot of modern. Cars like in any recent BMW, that paddle shifter is not moving linkages. It's just moving electrical contacts and telling a computer how to handle the transmission. Are the good conceptual demonstration of drive by wiring. In general is the steer-by wire setup in this development car. This is the X1 at the Stanford Automotive Innovations Lab. Now it starts off with a traditional steering wheel. Turns out, round still works well. But if you think it's like a game controller, it's a different feel. It has weight. It has feedback. It has mass to it. Now here's where things are very clearly different. At the end of this, there's no more steering linkage. And that's where drive-by-wire really becomes by-wire. Things look and feel very similar. Professor Chris Gurdy of Stanford has been working on assisted driving systems like this for some 20 years. What is the computer div? So the computer is sending commands to these amplifiers which are connected to the motors and so the computer will command a certain amount of twork to the wheel, and then it will look at the position of the wheel and see if it's gone to the right place. If it hasn't gone to the right place, it'll compensate it in the control algorithm to apply a little bit more twork. To turn the wheel until it gets to the right position. The benefits of drive by wire include better response, faster more precise actions by car systems can be handled by computers than by us. Some of the active safety systems that we've been working with will steer the wheel. In the event of an emergency. And we can steer the wheels the proper amount in an emergency much faster than most human drivers could, could judge that and then actually move the wheel. Automation, when systems are filtered through computers to either make our driving better or to recognize things we haven't seen yet and react to them. So this is very similar to the brake assist systems which sense that the driver is. Intending a panic stop and will put the brakes on fully even if the driver is still ramping upward with that demand. In dangerous situations, the electric motor triggers a full braking maneuver from the booster in the blink of an eye. Automation can also tune driver inputs to maximize performance, efficiency, and reduce emissions. Ergonomics. The controls you touch in the car can be made to feel best for the task. So maybe you want something that gives you a lot more assistance so that you're decoupled from the road. That would be very easy to program. Or maybe you actually like feeling the road and want something that feels a little closer to manual steering. That would also be easy to. And finally weight. A major reduction can be achieved by replacing heavy metal linkages and parts that exist today with more compact electric servos that live at the point of action. The challenges of drive-by-wire include communicating with the seat benefit. So many of these things really are most evident to the people designing the cars and selling the cars. From the driver's standpoint, they'll understand that things are different. You know, they'll see a difference in steering feel. But in order for them to really find that to be an advantage, it has to be better. Trust. Consumers, and to a degree, automakers, don't trust this yet. Your automaker will redesign accelerator pedals Especially in light of the recent Toyotagate situation. .>> just the idea that some bad software in a car Our accelerator's stuck. Could cause runaway acceleration spooked a lot of people. And I think it's natural for people to approach cautiously. The automakers have been fairly slow to introduce steer by wire for exactly that reason. The question of can they offer a great enough benefit to the driver for them to overcome any sort of hesitation they might have about. And finally fault detection. Your current car has limited, if any, of this. But in the Drive-By-Wire world, there has to be a lot of fault vigilant technology and built in backups. And all of it done economically. By many estimates, the amount of software that it takes to run the basic functions of steering and throttle is only about ten percent of what's on there. About 90% is fault detection, fault recovery. The sorts of things that you need to, to handle situations where things are not working perfectly. [MUSIC]