Human strength database and multidimensional data display

We study human figure modeling with strength capability to achieve more realistic and natural human motions in a task simulation. First, we develop a strength model and incorporate it in the computer graphics human figure definition. Strength information (maximum torques) is defined as muscle group strengths and is stored on a joint degree of freedom basis in the human figure model. Modeling strength in terms of muscle group strength allows different people to possess different capacities in different muscle groups. Each muscle group strength is modeled as a function of body position, anthropometry, gender, handedness, fatigue, and other strength parameters. In terms of body position, we choose a more generalized model that takes the effects of adjacent joint angles into consideration. To facilitate the use of strength information (data) in the human-task simulation environment, we have designed and implemented a relational strength database system. Because strength data are sparsely measured over the space of input parameters, we develop interpolation and scaling techniques for the system to estimate the strengths when they are not measured directly. To allow a user to have easy and effective access to the strength database, we have also designed and implemented an interface. To further enhance the effective use of the strength information, we develop graphical methods to display the multidimensional characteristics of the strength data. We use human figures together with two or three dimensional graphical symbols, colors, and other computer graphics techniques so that the user can visualize the effects of different parameters on strength. These displays give a dynamic changing view of the effects of parameters on strength, and illustrate safe and forbidden body postures (or regions) in terms of strength capability.