ITR/PE+SY Digital Clay for Shape Input and Display

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

Shape is a key element in successful communication, interpretation, and understanding of complex data in virtually every area of engineering, art, science, and medicine. While in recent years the communication of both form and complex data have been greatly enhanced by visualization that is based on planar images, computational power has reached the point where it is possible to consider real-time interactive 3D physical communication. In this project, the PI will develop a novel interactive 2D or 3D haptic computer interface that enables both user-specified display of shapes as output from a computer, and user-directed input of shapes to a computer. This so-called "digital clay" will allow users to convey and/or sense multiple-element, parallel information strands. It is a distributed input/display device, the surface of which can be shaped by a user and acquired by a computer; alternatively, the clay can be shaped by the computer for the user to examine. Like ordinary clay, digital clay will allow an area of moderate size to be touched, reshaped with pressure, and seen by the user in true 3D form. Unlike ordinary clay, digital clay also provides parameters to the computer that will represent the shape to the computer for further analysis, storage, replication, communication and/or modification; or, will allow the computer to prescribe its shape. This combined input and output feature of the clay enables two-way communication between the computer and the user. Some previous implementations of digital-clay-like devices have focused on reshaping of non-physical volumes of 'virtual clay' using glove-like or haptic manipulator interfaces to a computer in which the virtual clay is stored. The PI's approach is different; digital clay comprises an instrumented, actuated, computer-interfaced physical volume bounded by an actuatable surface that acts as the haptic interface. This surface is displaced by rows or arrays of controllable interconnected fluidic-driven actuators, which together act to convey the surface topography of 3D objects by means of manipulation of a stereolithographed scaffold internal to the volume of the clay. Each actuator comprises a discrete fluidically-inflatable cell that is connected to two common pressurized reservoirs (within a base) through a dedicated two-way miniature valve integrated with a pressure sensor, manufactured by MEMS technology existing at Georgia Tech. The position of each discrete surface element can be altered either by the user or by the host computer. The simple measurement of volume flow rate combined with suitable software-based kinematic analysis allows the determination of the entire volume of the clay, and therefore the coordinates of its surface. A unique feature of the digital clay is that the force that is necessary to actuate the discretized surface is derived entirely from the two fluidic reservoirs, thus eliminating the need for small-scale, electrically-driven actuators that may have limited torque or linear force. This fluidic approach overcomes the constraints imposed by actuator energy density limits, and distributed wiring and sensing requirements, that have heretofore prevented structures such as digital clay from becoming a reality. Furthermore, the user can activate the device interactively with the host computer by sensing and overcoming the force that is exerted by the liquid pressure to concomitantly set (or reset) the shape of the device to a desired state. In this project the PI will develop and demonstrate the digital clay hardware, its computer interface, and associated software, and will further illustrate its efficacy in applications of interest (e.g., computer-aided design, medical and bioengineering diagnostics, and reconfigurable input/output displays). Of particular note is the potential of digital clay to aid visually impaired persons in receiving/sending haptic information from/to a computer.