Whenever it debuts a new car, BMW usually receives plaudits, not brickbats.But when it recently unveiled its new flagship 7-Series it faced a chorus of criticism about certain aspects of the vehicle, ranging from the exterior styling to the instruction cards included for parking valets so they could learn the complex maneuver of, ah, parking it. But the area that was singled out for the most derision was the iDrive user interface that consolidates control over 700 functions in one large knob. Ironically, the iDrive system has drawn criticism for being too complicated though its chief premise is simplification.
Two major areas are placed under iDrive's control: a driving zone, which centers on functions like steering and shifting, and a comfort zone. The comfort zone includes the navigation system, the telephone book for the on-board phone, audio equipment settings, customized climate control, and more. To use iDrive, the driver (or passenger) manipulates a large silver knob (the "controller") located atop the center console in order to navigate and select functions displayed on a screen in the center of the instrument panel.
Key to the functionality is tactile feedback, which is said to allow people to gather information through the sense of touch, while simultaneously allowing them to focus on other tasks–like keeping their eyes on the road. It provides complex sensations that let practiced users tunnel through multiple menus without looking at the display. For example, when scrolling down a phone list the knob will emit a tactile "bump" whenever a name is passed to give the operator a sense of speed and location.
To help develop the tactile feedback aspect of iDrive, BMW turned to Immersion Corp. (San Jose, CA), a small Silicon Valley company that previously worked primarily on enhancing the feel of gaming joysticks and computer mice. Immersion developed the software that assigns unique sensations through the control knob to corresponding images on the system's monitor. It also designed the control unit and oversaw prototype production. (Mass production is being handled by Alps Electric.)
Immersion uses some programming sleight of hand to achieve its effects, but the hardware is pretty straightforward. The compact unit is essentially made up of an off-the-shelf motor and actuators. A high-resolution position sensor determines the relative position of the knob, and drives the motor against the motion of the operator the exact amount necessary to create the desired force feedback sensation. The motor itself has a skewed rotor like those found in inkjet printers which eliminates the detent torque that would coarsen the feel.
The feedback system has the capability of creating a wide array of tactile sensations, but BMW and Immersion chose to stick to familiar ones, lest people be overwhelmed and–ultimately–turned off. So, adjusting the bass or treble with the iDrive control knob feels just like it does on a conventional sound system. And zooming in on a navigation map simulates the feel of the zoom function on a camera.
Although the number of things the iDrive can do is vast (some think too vast), during development a question being asked was how much was enough. "We don't think functions that are highly immediate or have a high frequency of use make sense to fold into a graphical or contact-sensitive user interface," says Steve Vassallo, senior director of mechanical engineering at Immersion. "If the kids are screaming and you need to turn the volume down quickly, you don't want to have to tunnel through a menu to get to that." Therefore, some functions like temperature, fan speed and audio volume maintain their dedicated controls on the instrument panel, but almost everything else is selected and adjusted via the iDrive knob.
One of the chief aims of iDrive–as well as a number of other systems with tactile feedback components that are beginning to emerge—is the reduction of driver distraction through the transfer of some informational load from the visual to the tactile. Immersion claims their system can shave tenths of a second off emergency response times by keeping a driver's eyes on the road. It also promises to reduce the overall amount of time needed to make adjustments. As Vassallo points out, "Touch is really the only bi-directional sense. That is, you can manipulate something and immediately feel the results of that manipulation. So you can close the loop that much faster."
Instrument panel design stands to benefit as well. The recent explosion of in-car functions has turned some automotive cockpits into a dog's breakfast of knobs and switches. But as the 7-Series cockpit illustrates, with a single knob controlling most functions, the number of single-purpose controls can be kept to a minimum.
iDrive also addresses the challenge of upgrading functionality as technology changes. One of the things that stymies automotive electronics engineers tasked with incorporating the latest gadgets into cars is the comparatively long life cycle of the automobile. Cell phones and personal digital assistants follow 12 to 18 month cycles, while cars often last 10 years or more. Upgraded iDrive software can be downloaded at the dealership in the form of enhancements to existing functions or the addition of new ones, each of which has its own tactile sensations.
Lowering Cost and Complexity
Since Immersion's background was in consumer electronics, it brought a low-cost mindset to the iDrive project. Vassallo says, "The whole thinking process started with how to make a very inexpensive but robust system. It had to feel good, but use low-cost components. So, from the get-go, we were using $2.50 motors." The most expensive part of the whole assembly is a Motorola microprocessor.
Even though a tactile feedback system can eliminate dedicated switches and the cost and complexity that go with them, in order to make the most of the system it needs to be hooked up to an expensive display screen. However, as screens move from upscale vehicles to more modest rides, screen prices should drop, which will make this interface even more attractive.
Vassallo thinks tactile feedback technology use in vehicles will expand over the next few years, and adapt to fill different roles. Immersion worked with Nissan to develop a scroll wheel mounted on the steering wheel of its 2003i concept car so that the driver can keep both hands on the wheel while adjusting functions, and is supporting Nissan's Japanese market Primera program.
Additionally, Siemens VDO recently showed a cockpit concept with a tactile feedback rotary knob, and similar controllers have been featured in concepts like Audi's Avantissimo and Johnson Controls' Etimos.
As for BMW, the initial criticisms of iDrive have not deterred the company. According to Thomas Jefferson, 7-Series product manager, "BMW is committed to the iDrive concept. And you can expect to see appropriate applications of it in our future products." He continues, "Right now, since no one else is doing it, it seems like BMW is out on a limb, but I guarantee that within the next two model years we'll be seeing it from other manufacturers."