Biomedical Engineering Reference
In-Depth Information
as virtual joints to distinguish them from the physical human joints. The two adja-
cent virtual joints are connected by a virtual link which uses zero mass and zero
inertia to define the link properties. Finally, the virtual joints and links constitute
a virtual branch which contains six global DOFs (
z
1
,
z
2
,
z
3
,
z
4
,
z
5
,
z
6
).
The virtual joints defined in the virtual branch not only generate global rigid
body movements but also contain global generalized forces. These forces corre-
spond to the six global DOFs: three forces (
τ
1
,
τ
2
,
τ
3
) and three moments (
τ
4
,
τ
5
,
τ
6
).
For the system in equilibrium, these global generalized forces should be zero.
2.15
Concluding remarks
This chapter has presented the kinematics of human modeling. It is evident that
the human body is complex, requiring a true multi-disciplinary approach among
researchers from the medical field and from engineering. Detailed physics-based
modeling of human joints may require far more knowledge than is currently avail-
able. However, for all practical purposes, it has been shown that approximate
modeling of gross human motion, for the purpose of human motion simulation or
ergonomic analysis, can be achieved using the Denavit
Hartenberg representa-
tion method. The DH method provides an adequate, consistent, and systematic
method for embedding the local coordinate systems for each link. Furthermore,
the DH method allows for the modeling of complex and large DOF skeletons,
where each complex joint has multiple DOF. Lastly, the DH method lends itself
well to computational methods and we will expand on this foundation in later
chapters to build the dynamics of the motion, leading to predicting how humans
will respond to a given situation.
References
Abdel-Malek, K., Yu, W., Jaber, M., 2001a. Realistic Posture Prediction. 2001 SAE
Digital Human Modeling and Simulation.
Abdel-Malek, K., Wei, Y., Mi, Z., Tanbour, E., Jaber, M., 2001b. Posture prediction versus
inverse kinematics. In: Proceedings of the 2001 ASME Design Engineering Technical
Conferences and Computers and Information in Engineering Conference. Pittsburgh,
PA, pp. 37
45.
Abdel-Malek, K., Yu, W., Jaber, M., Duncan, J., 2001d. Realistic Posture Prediction for
Maximum Dexterity. SAE Technical Paper 2001-01-2110. doi:10.4271/2001-01-2110.
Maurel, W., Thalmann, D., Hoffmeyer, P., Beylot, P., Gingins, P., Kalra, P., et al., 1996.
A biomechanical musculoskeletal model of human upper limb for dynamic simulation.
In: Computer Animation and Simulation. Springer Vienna, pp. 121
136.
Pieper, D.L., 1968. The Kinematics of Manipulators Under Computer Control. Ph.D.
Thesis, Stanford University.
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