Since the subchain of (R-L)-S-R has a fourth-degree
polynomial equation in inverse kinematics, there are up to
four possible solutions in Eq. (2.25). However, the
possible solutions may be reduced due to special dimensions
of the subchain as shown in the following example.
Numerical example. The given parameters are as
follows:
a = 5", b = 3", ac = 0, c = 0.75", sc = 1.50" and
0.9300 -0.3323 -0.1574 8.3382
-0.3466 -0.9352 -0.0734 0.2201
HO =
-0.1228 0.1228 -0.9848 -1.5205
0 0 0 1
L
Since two of the solutions of Eq. (2.25) are complex
numbers, the remaining two possible real solutions are
computed as
Solutions c ea da 8bl 6b2 8b3
(deg.) (deg.) (in.) (deg.) (deg.) (deg.)
1 33.435 -1.008 0.559 26.009 -10.002 11.565
2 14.988 10.009 0.500 14.992 -10.002 30.012
2.5.4 Subchain (R-L)-S-P
The procedure of inverse kinematics of the subchain (R-
L)-S-P, as shown in Fig. 2.14, is similar to that of the