From Force Feedback Manipulanda to Surface Haptics: Part I
(In which we establish that Haptics ≠ Buzz)
When you see the word haptics, what comes to mind? If you’re like most people, the initial thought is something like, “huh?” Believe me, I’ve done the polling. But that’s changing fast. These days a lot more people have heard the word because a lot more consumer products advertise it. When I ask those folks what it means, the usual response is something along the lines of “a buzzing feeling.” Although it makes me cringe, I can’t blame them. “Haptics = buzz” is a pretty logical conclusion if that has been your direct experience. But the reality is: haptics is so much more.
I remember when I first heard the word. It was 1992 and I was attending a robotics conference in Kobe, Japan where Ken Salisbury who was (and remains) one of the truly esteemed roboticists of the day, used it. He used it to describe a class of machines that a few of us had begun to develop. Most of us called those machines “force feedback manipulanda” or something equally melodious. That made sense to our engineering minds because these were basically lightweight robots that a person could grasp and move, and the robot would push back according to the physics of some virtual environment. Pick up a virtual box and you would feel its heft. Push it along a virtual floor and you would feel the friction.
By choosing the word “haptic”, Ken was reframing, changing the focus from what the machines did to what the human experienced: haptic perception. For the record, I don’t know who first used the term “haptic interface”, but it was a brilliant choice. Not just because it is a cool word (it is!), but because it is the right word. Long before we engineers got into the act, cognitive psychologists such as J.J. Gibson had been using “haptic” to refer to something much broader than the word “tactile.” Haptic perception refers to the act of extracting information from the environment by touching, feeling, groping, probing and manipulating.
Those early devices really were haptic. A person would grab onto a handle as if it really were the handle of, say, a scalpel. She would then begin to cut tissue, watching a real-time graphical simulation and feeling the forces in her hand. Done right, the feel of cutting connective tissue, muscle, sinew and bone would all be quite distinct and darned realistic. It was, and remains, some pretty cool technology.
So, what’s up with buzz?
At some level, we all know the answer to that question: smartphones. Actually, before there were smartphones there were pagers which used vibration for one purpose only — alerts. I think that most people would agree that buzzes make mighty fine alerts! And smartphones needed alerts as well, so it was natural to make them buzz. And once you had combined buzz with a lot of processing power and a touch-based interface… well, the rest is history.
But let’s take a step back and think about where this has brought us. In a previous post, I wrote about the evolutionary purposes of haptics. They basically boiled down to:
- Help me identify things that are good (like ripe fruit) and bad (like a mosquito on my arm), and
- Help me to manipulate things with dexterity
Now ask yourself the question: Which of these functions is the one we’ve appropriated for our devices? Yeah, you guessed it — we’ve taken the alert system that evolved to help us swat flies and we’ve turned it into advanced user interfaces. No wonder they haven’t caught on…
Ok, ok, I’m painting with a pretty broad brush here. As anyone who’s visited a Brookstone and lounged in one of those massage chairs knows, vibrations can feel pretty nice. But that’s not really the point. Instead, the point is that haptics offers amazing opportunities to provide pleasant, aesthetic experiences and to enhance dexterity. Haptics can be so much more than buzz!
The challenge, however, is accomplishing something more than buzz on the surface of a smartphone. Back in the day, we had the advantage of being able to grasp our force feedback manipulanda, but a bare fingertip on a piece of glass is a decidedly more challenging proposition. About ten years ago, my colleague Michael Peshkin and I, along with students in our lab, started to work on this problem. In Part II of this post, I’ll explain how we harnessed friction to solve this problem.
