Gadgetory

the basic concept behind drive-by-wire which is also known as ex by wire sometimes is to replace all these physical controls in the vehicle like steering braking an 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 vehicles drive systems get into your vehicle and I 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 I'm a shifter in a lot of modern cars like in any recent BMW that paddle shifters 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-wire in general is the steer-by-wire setup in this development cars 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 very 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 Gertie's at Stanford has been working on assisted driving systems like this for some 20 years what does the computer do 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 torque to turn 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 in the control algorithm to apply a little bit more torque 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 wheels 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 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 a 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 up with that command 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 it 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 it feels even closer to manual steering that would also be easy 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 the perceived benefits so many of these things really are most evident to people designing the cars and selling the cars from the drivers 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 the automaker will redesign accelerator pedal especially in light of the recent Toyota Gate situation we're just the idea that some bad software in a car 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 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 10 percent of what's on there and about 90 percent is fault detection fault recovery the sorts of things that you need to handle situations where things are not working