It's all part of the relatively new science of haptics, the science of integrating the sense of touch into human-machine interactions. Researchers in Perceptual Design of Manufacturing & Vehicle Design R & A have collaborated with staff from Powertrain Operations and Core Ergonomics of NAPD to apply haptics to the floor shifter, which will be mated with the new 6F transmission.
"Through our work we have been able to quantify the sense of touch as it applies to vehicle controls," said Yifan Chen, technical leader, Perceptual Design. "Our major work last year was helping EESE (Electrical Electronic Systems Engineering) design operating feel for the HVAC (Heating, Ventilation and Air Conditioning) switches on the Fusion/Milan/Zephyr midsize sedans. We took the results of our work on switches and are now applying it to improving shifter "feel."
The switch research Chen refers to involved a haptic switch playback system developed entirely by Ford staff. It is capable of reproducing a wide range of switch-feel. With this system, the user can change the characteristics of a switch (factors such as friction or force) and feel the difference as the changes are made. Groups of subjects manipulated the switches as the software changed parameters, i.e. the feel of the switch turning, and reported their perceptions of the experience and their preferences.
The parameters investigated were narrowed down to only those that made a difference to the test subjects's perception. In addition, a simple computer game measured the subjects' ability to manipulate onscreen items using the switches as if they were joysticks.
"The results were fascinating," said Pietro Buttolo, technical specialist, Perceptual Design. "People were able to master the game better with the switches that were in the same range as the ones they found the most pleasing. Clearly, the brain is integrating feel with function."
The immediate benefit of the team's work was a system to quantify the feel of switches in order to not only create switches pleasing to the driver, but also a way of creating a common feel to all the switches on a vehicle's dashboard. "We've found that if we can control the parameters defining "feel" within a specific range, most people cannot tell the feel of a two switch apart," Buttolo said. "This makes a difference to people, when all the switches have a commonality, even if the difference is felt unconsciously."
In addition, the team's work resulted in significant cost savings to Ford through the elimination of most prototypes for switches. "Prototypes are created in the computer instead of the time consuming and expensive process of having suppliers create a number of physical prototypes to achieve the desired feel," explained Chen.
With a solid baseline of research accomplished, the team began applying its knowledge to the new floor shifter.
"The shifter presented us with a challenge," Chen said. "Basically the shifter attaches to a cable which leads to the transmission. For our very first target program, the transmission, a joint venture between Ford and GM, is basically set as is the cable. In effect, we are constrained to a narrower range of possibilities by the transmission and cable hardware."
As in the switch work, subjects manipulated a tabletop model of a shifter or one in a test vehicle, while team members varied characteristics like force, friction and the shape of the shifting pattern through the software.
"We gave the Perceptual Design team a specification to work with," said Harbinder Virdee, shift systems engineer, Powertrain Operations. "In this case all we had was that the shifter effort should be between 12 and 30 Newtons. We wanted to understand what other factors influenced a customer's positive perception of the way a floor shifter felt."
As with the switches, the team is working within a range of possible feels. "The average driver isn't that concerned about one feel over the other as long as it falls within an acceptable range," Virdee said.
While drivers may not be consciously aware of fine differences between possible shifting feels, they are aware of how well a component functions and with a shifter that can possibly mean safety issues.
"Customers take the vehicles they drive as an extension of their personal qualities. They are looking for harmonious and delightful experiences," said Chin-Yuan Perng, section supervisor, Dynamics CAE and VSA, Automatic Transmissions. "For example, the customer experiences a vehicle's transmission through the working of the shifter. Touch and feel of the shifter motion deliver the first impression of the vehicle quality."
Again, the correspondence between what people like and what works best is striking. As the team plots a curve for the feel people like best, it comes close to the curve of what works best.
"People 'like' what is safe," Buttolo said. "There is an essential harmony in human beings between the sense of touch and the brain's more logical functions."