Giving Santos™ Movement: Posture Predication
New human performance measures that govern motion are constantly being developed. For example, the method with which discomfort is modeled has been updated based on the lexicographic approach to multi objective optimization. In this way, segments of the body are prioritized and used one at a time. Some of the cost functions that are currently implemented in Santos™ include discomfort, fatigue, effort, energy and vision. Concurrently, the discomfort increases as joints approach their limits. Additionally, a new energy function is being developed which is based on the change in potential energy of the arms and the torso. An orientation constraint has been developed and incorporated in the optimization-based approach. Thus, a new method for governing the orientation of any component of a human model is being developed. A relatively simple constraint or rule is added to an optimization formulation, allowing the stipulation of a global direction for either one or two local reference-frame-axes (X,Y,Z).
The mathematical model of a skeleton for Santos™ is developed based on the Denavit-Hartenberg method for kinematic and dynamic analysis. Optimization code is used to determine postures that are governed by various human performance measures (objective functions) and constrained by the restrictions imposed by the skeleton, physical constraints, and environmental constraints. This code must be as fast and efficient as possible in an effort to provide real-time simulations.
