The Novint Falcon, a low-cost haptic device that we first mentioned briefly here, will soon allow more consumers and engineers to get in touch with their computers — literally.
The Falcon will sell for just $239, including software. It will initially serve as a game controller, one that allows users to “feel” objects that exist only within the game environment. For example, the system would allow you to touch a virtual wall or engage in a virtual handshake with another game player.
Even at such a low price, the Falcon doesn't skimp on performance. According to Novint CEO Tom Anderson, the Falcon offers positioning resolution, maximum forces and free-space movement on par with much more expensive devices. “Its fidelity is similar to haptic devices costing more than $10,000,” Anderson says.
Those high-end haptic devices, such as the ones from SensAble, tend to have a serial linkages. Novint takes a very different mechanical approach, one inspired by the parallel mechanisms used on high-speed Delta robots.
In fact, you can think of the Falcon as a Delta robot set on its side. In place of a moving plate and end effector, though, the Falcon has interchangeable grips that the user holds onto during games. A grip's position in real space corresponds to the location of a cursor in the game's three-dimensional virtual world. And when that cursor touches a virtual object, the Falcon sends an analogous force back to the grip. Likewise, forces the user exerts on the grip are translated into cursor movements.
Anderson, who began working with haptic systems as an engineer at Sandia National Laboratories, argues that parallel mechanisms are a natural fit for haptics because they offer good stiffness and robustness at a relatively low cost. Stiffness, in particular, is important in haptics, which all tend to have somewhat “squishy” interactions with virtual objects because motors can’t respond instantaneously.
The Falcon generates its real world forces with three small joystick-sized motors connected to the device's three arms by a cable linkage. The system can produce a force in any direction within its 4 x 4 x 4 inch working envelop up to a maximum of roughly 2 lb.
Novint's control software for the Falcon that adjusts the motor current in accordance with what's happening in the virtual world — with textbook physics equations determining the magnitude and vector off all the forces and deflections. For example, the spring force equation (F=-kx) sees lots of use as a way to relate the deflection of virtual objects to opposing forces in the real world haptic system. The system updates current and positions — real and virtual — at 1 kilohertz. Anderson says the system achieves a sub-mm resolution.
The Falcon may be getting its start as a game controller, but Anderson believes that the system's low cost could help usher in a haptics revolution akin to what the mouse did for computing. “The Falcon isn't just one device, it's a haptic platform that could be applied more broadly as a 3D input device,” he says. Novint plans to license its haptics technology to third parties interested in developing haptic interfaces for a variety of computing systems, including design and analysis software used by engineers.