We present a numerical scheme for the real-time solution of the discretized one-dimensional linearized acoustics equation (Webster's equation) augmented with dissipative terms, in a tube with a spatially and temporally varying cross section. The resulting algorithm produces similar results as the Kelly–Lochbaum model but has several advantages over it: the tube length can change continuously, the area function can change in time and can be governed by a dynamical model itself, the scheme is of second-order accuracy, and the spatial and temporal discretization does not need to be uniform. We show how the model can be used to build a realistic real-time audio synthesis method for articulatory speech synthesis by coupling it to a lip radiation model, a dynamical wall model, and a glottal excitation model.

A physically based liquid sound synthesis methodology is developed. The fundamental mechanism for the production of liquid sounds is identified as the acoustic emission of bubbles. After reviewing the physics of vibrating bubbles as it is relevant to audio synthesis, a sound model for isolated single bubbles is developed and validated with a small user study. A stochastic model for the real-time interactive synthesis of complex liquid sounds such as produced by streams, pouring water, rivers, rain, and breaking waves is based on the synthesis of single bubble sounds. It is shown how realistic complex high dimensional sound spaces can be synthesized in this manner.

Wherever we are, what we hear is mostly noise. When we ignore it, it disturbs us. When we listen to it, we find it fascinating. The sound of a truck at 50 mph. Static between the stations. Rain. We want to capture and control these sounds, to use them, not as sound effects, but as musical instruments.---John Cage on the future of music---from a lecture given in 1937

We describe algorithms for real-time synthesis of realistic sound effects for interactive simulations (e.g., games) and animation. These sound effects are produced automatically, from 3D models using dynamic simulation and user interaction. We develop algorithms that are efficient, physically-based, and can be controlled by users in natural ways. We develop effective techniques for producing high quality continuous contact sounds from dynamic simulations running at video rates which are slow relative to audio synthesis. We accomplish this using modal models driven by contact forces modeled at audio rates, which are much higher than the graphics frame rate. The contact forces can be computed from simulations or can be custom designed. We demonstrate the effectiveness with complex realistic simulations.

We describe a system for constructing computer models of several aspects of physical interaction behavior, by scanning the response of real objects. The behaviors we can successfully scan and model include deformation response, contact textures for interaction with force-feedback, and contact sounds. The system we describe uses a highly automated robotic facility that can scan behavior models of whole objects. We provide a comprehensive view of the modeling process, including selection of model structure, measurement, estimation, and rendering at interactive rates. The results are demonstrated with two examples: a soft stuffed toy which has significant deformation behavior, and a hard clay pot which has significant contact textures and sounds. The results described here make it possible to quickly construct physical interaction models of objects for applications in games, animation, and e-commerce.

We present a geometric theory of the performance of robot manipulators, applicable to systems with constraints, which may be nonholonomic. The performance is quantified by a geometrical object, the induced metric tensor, from which scalars may be constructed by invariant tensor operations to give performance measures. The measures thus defined depend on the metric structure of configuration and workspace, which should be chosen appropriately for the problem at hand. The generality of this approach allows us to specify a system of joint connected rigid bodies with a large class of metrics. We describe how the induced metric can be computed for such a system of joint connected rigid bodies and describe a MATLAB program that allows the automatic computation of the performance measures for such systems. We illustrate these ideas with some computations of measures for the SARCOS dextrous arm, and the Platonic Beast, a multilegged walking machine.

We introduce a formalism for the systematic construction of performance measures for robot manipulators in a unified framework based on differential geometry. We show how known measures arise naturally in our formalism and we construct some new measures. The new measures presented here are the effective inertia on workspace and the kinematic and dynamic anisotropy measures for redundant manipulators.>

We investigate two new classes of performance measures. The first class quantifies the ability of a redundant manipulator to reconfigure itself while keeping the end-effector at a fixed position. The second measures the nonlinearity of the manipulator. We derive these measures using the differential-geometric formalism we introduced previously (1993).>

Investigates the construction of performance measures for robot manipulators with closed kinematic loops. For such systems, the equations for the forward kinematics and the constraints can not be solved explicitly in general. The authors extend a formalism introduced by them previously (1993, 1994) based on the construction of an "induced" metric tensor on the work space of the manipulator, to include systems with constraints (which may be non-holonomic). As an example of an application the authors compute the generalized Yoshikawa measure for a planar five-link closed linkage chain, which they use to compute some optimal postures.>