3.3 Adjoint

The adjoint in $ \mathrm{SE(3)}$ is computed from the generators, just as in $ \mathrm{SO}(3)$:


$\displaystyle \boldsymbol{\delta}=\left(\begin{array}{cc}
\mathbf{u} & \boldsymbol{\omega}\end{array}\right)^{T}$ $\displaystyle \in$ $\displaystyle \mathrm{se(3)},\; C=\left(\begin{array}{c\vert c}
\mathbf{R} & \mathbf{t}\\
\hline \mathbf{0} & 1
\end{array}\right)\mathbf{\in}\mathrm{SE(3)}$ (78)
$\displaystyle C\cdot\exp\left(\boldsymbol{\delta}\right)$ $\displaystyle =$ $\displaystyle \exp\left(\mathrm{Adj}_{C}\cdot\boldsymbol{\delta}\right)\cdot C$  
$\displaystyle \exp\left(\mathrm{Adj}_{C}\cdot\boldsymbol{\delta}\right)$ $\displaystyle =$ $\displaystyle C\cdot\exp\left(\boldsymbol{\delta}\right)\cdot C^{-1}$ (79)
$\displaystyle \mathrm{Adj}_{C}\cdot\boldsymbol{\delta}$ $\displaystyle =$ $\displaystyle C\cdot\left(\sum_{i=1}^{6}\boldsymbol{\delta}_{i}G_{i}\right)\cdot C^{-1}$ (80)
  $\displaystyle =$ $\displaystyle \left(\begin{array}{c}
\mathbf{R}\mathbf{u}+\mathbf{t}\times\mathbf{R}\boldsymbol{\omega}\\
\mathbf{R}\boldsymbol{\omega}
\end{array}\right)$ (81)
$\displaystyle \implies\mathrm{Adj}_{C}$ $\displaystyle =$ $\displaystyle \left(\begin{array}{c\vert c}
\mathbf{R} & \mathbf{t}_{\times}\ma...
...R}\\
\hline \mathbf{0} & \mathbf{R}
\end{array}\right)\in\mathbb{R}^{6\times6}$ (82)

Note that moving a tangent vector via the adjoint mixes the rotation component into the translation component.



Ethan Eade 2012-02-16