ABSTRACT
Consider the 17-member human body model of Chapters 6 and 8 and as shown again in Figure 11.1. As noted earlier, we may regard this model as an open-chain or open-tree collection of rigid
bodies. As such, we can number or label the bodies as before and as shown in the gure. Recall that with this numbering system, each body of the model has a unique adjacent lower-numbered body. Specically, as in Chapters 6 and 8, we may list the adjacent lower-numbered bodies L(K) of each of the bodies (K) as in Equation 6.11 and as listed again here:
K
L K
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 ( ) 0 1 2 3 4 5 3 7 3 9 10 1 12 13 1 15 16
(11.1)
Observe further that with this modeling, the bodies are connected to each other by spherical (balland-socket) joints. Then each body (except for body B1) has three rotational degrees of freedom relative to its adjacent lower-numbered body. Body B1, whose adjacent lower-numbered body is the xed (inertial) frame R, has six degrees of freedom in R (three rotations and three translations). The entire model thus has a total of (17 × 3) + 3 or 54 degrees of freedom.
