This project will advance the science and technology of magnetic-levitation-based haptic interfaces by developing an untethered hand-held interface in which magnetic forces are applied to a freely moving tool rather than a handle that is physically attached to a larger device. The project will extend force-feedback devices into a new wave of development that incorporates free mobility. Current haptic devices use mechanically linkages to impart forces and torques to the user. These new untethered devices will use projected magnetic fields and an externally tracked tool so that the user is freed from any physical linkage. The project will contribute to the development of new microsurgical systems that can be used to train and evaluate novice surgeons prior to conducting surgery on actual patients.
This project will investigate a new type of magnetic haptic interface, an untethered magnetic interface that renders force/torque to a permanent magnet attached to a stylus by using electromagnets that project their magnetic fields into free space. The position and orientation of the permanent magnet must be tracked to provide feedback for the device to work as a haptic interface. Unlike Lorentz-force interfaces, which must encase a portion of the stylus, the project will produce an untethered interface in which the stylus can be completely removed from the electromagnet system, thus eliminating the physical linkage between the haptic stylus and the rest of the system, and reducing stylus inertia to only that of the stylus itself. The project has three goals: (1) To develop the analytical relationships that will govern untethered magnetic haptic interfaces. Many of the existing basic principles for haptic devices will need to be reconsidered, such the fundamental trade-offs among workspace size, stylus inertia, maximum force/torque generation, maximum stable surface stiffness, and sampling update rate. (2) To adapt high-speed image-processing techniques to track the six degrees of freedom of movement that are possible in an untethered manual tool. (3) To realize a prototype magnetic haptic interface that is optimized for simulating cataract surgery.
