“Controlling dynamic simulation with kinematic constraints” by Isaacs and Cohen

Theoretical and numerical aspects of the implementation of a DYNAmic MOtion system, dubbed DYNAMO, for the dynamic simulation of linked figures is presented. The system introduces three means for achieving, control of the resulting motion which have not been present in previous dynamic simulation systems for computer animation. (1) “Kinematic constraints” permit traditional keyframe animation systems to be embedded within a dynamic analysis. Joint limit constraints are also handled correctly through kinematic constraints. (2) “Behavior functions” relate the momentary state of the dynamic system to desired forces and accelerations within the figure. (3) “Inverse dynamics” provides a means of determining the forces required to perform a specified motion.The combination of kinematic and dynamic specifications allows the animator to think about each part of the animation in the way that is most suitable for the task. Successful experimental results are presented which demonstate the ability to provide control without disrupting the dynamic integrity of the resulting motion.

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