Abstract: Generally, the simulation of a human task with a computer-aided ergonomic system is always
required in all the modern engineering activities, and it is one of most specialized and complicated
works. So it is of importance to research and set up the procedure for rapidly planning a task simulation.
But a great deal of interactions is needed during the application of current ergonomic systems so far,
and the simulation steps cannot be created automatically. This paper proposes methods for rapidly
planning the task simulation and automatically generating the simulating steps according to the division
of the task semantics. Firstly, with the structure of hierarchical scheme, the natural semantics of an
ergonomic task are divided into layers, in which all the leaf nodes are defined as the actions which can
be performed or implemented with an ergonomic system at present. Secondly, the new concepts of task
path, task trace and task process are defined, and the complex task is structurally modeled with the
application of a proposed graphic scheme. The procedure of automatic generation of a task simulation
steps is constructed. Finally, the program is developed, which is required to support the implementation of the established methods for planning the task simulation and automatically producing the simulation
data. Taking the opening of a board of fixture during the aircraft assembly, these proposed methods are
tested and verified.

Key words: semantic division, ergonomic simulation, process planning, automatically generating