Graphical simulation of the motion of articulated bodies such as humans and robots, with particular emphasis on the use of dynamic analysis (computer graphics, biomechanics)

Animation of articulated (jointed) bodies is of interest for several reasons. Inclusion of animal life in computer graphics images will increase their realism and interest. Computer graphical representations of the motion of humans and animals are useful tools in biology, biomechanics, medicine, and sports. Simulation of the motion of robots and other articulated machines using computer graphics can be useful for design and testing in CAD/CAM. Animation of articulated bodies presents a number of difficulties due to the complexity of possible motion. The usual method of specifying such motion is kinematics, which describes motion in terms of positions taken over time without consideration of the forces and torques causing the motion. An alternative means presented here is dynamics, where motion is described in terms of the influence of forces and torques on mass to cause acceleration. Although more complex and computationally expensive, dynamic analysis does predict motion that is realistic for the conditions specified. Advantages and disadvantages of the two methods are discussed. For ease of use, both methods would require high-level control routines so that the user could describe the motion in general terms (what to do), rather than the details of local joint behavior (how to do it). A system, Deva, is described which combines the facility for both kinematic and dynamic animation of articulated bodies.