Simulation of human movement for ergonomic design on numerical mock-up

In the held of computer-aided vehicle design, it is important to simulate the activity of the future end user in order to evaluate the product being designed on the basis of ergonomic criteria such as ingress/egress, encumbering, control reach, control maneuverability, and visibility. This can be done with a computerized graphical mannequin. Some of the problems related to this question are reviewed and a method of mannequin manipulation for posture simulation is presented. Tn this method, the postures and movements implied by the use of the product being designed are generated from position and orientation constraints assigned by the user to various body parts. An inverse geometric algorithm then computes a set of angles satisfying the geometric constraints. The algorithm is based on a functional segmentation of the human body into autonomous mobile segments, organized in a tree-like structure and able to cooperate in order to solve an inverse geometric problem. The resolution strategy is based on an action plan, decomposing the global constraint problem into local subproblems handled by the segments and taking into account priority levels of action attributed to the segments. Some examples of postures obtained with this method related to the use of an automobile are presented.