5.3 Adjoint

The adjoint in $ \mathrm{SE(2)}$ is computed from the generators:


$\displaystyle \boldsymbol{\delta}=\left(\begin{array}{cc}
\mathbf{u} & \theta\end{array}\right)^{T}$ $\displaystyle \in$ $\displaystyle \mathrm{se(2)},\; C=\left(\begin{array}{c\vert c}
\mathbf{R} & \mathbf{t}\\
\hline \mathbf{0} & 1
\end{array}\right)\mathbf{\in}\mathrm{SE(2)}$ (129)
$\displaystyle \mathrm{Adj}_{C}\cdot\boldsymbol{\delta}$ $\displaystyle =$ $\displaystyle C\cdot\left(\sum_{i=1}^{3}\boldsymbol{\delta}_{i}G_{i}\right)\cdot C^{-1}$ (130)
  $\displaystyle =$ $\displaystyle \left(\begin{array}{c}
\mathbf{R}\mathbf{u}+\theta\left(\begin{ar...
...athbf{t}_{2}\\
-\mathbf{t}_{1}
\end{array}\right)\\
\theta
\end{array}\right)$ (131)
$\displaystyle \implies\mathrm{Adj}_{C}$ $\displaystyle =$ $\displaystyle \left(\begin{array}{c\vert c}
\mathbf{R} & \begin{array}{c}
\math...
...\end{array}\\
\hline \mathbf{0} & 1
\end{array}\right)\in\mathbb{R}^{3\times3}$ (132)

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



Ethan Eade 2012-02-16