+ * Actuator to joint
+ * |
+ *
+ * \f{eqnarray*}{
+ * \tau_{j_1} & = & n_{j_1} n_{a_1} \tau_{a_1} \\
+ * \tau_{j_2} & = & n_{j_2} (n_{a_2} \tau_{a_2} - n_{j_1} n_{a_1} \tau_{a_1})
+ * \f}
+ * |
+ *
+ * \f{eqnarray*}{
+ * \dot{x}_{j_1} & = & \frac{ \dot{x}_{a_1} }{ n_{j_1} n_{a_1} } \\
+ * \dot{x}_{j_2} & = & \frac{ \dot{x}_{a_2} / n_{a_2} - \dot{x}_{a_1} / (n_{j_1} n_{a_1}) }{ n_{j_2}
+ * } \f}
+ * |
+ *
+ * \f{eqnarray*}{
+ * x_{j_1} & = & \frac{ x_{a_1} }{ n_{j_1} n_{a_1} } + x_{off_1} \\
+ * x_{j_2} & = & \frac{ x_{a_2} / n_{a_2} - x_{a_1} / (n_{j_1} n_{a_1}) }{ n_{j_2} } + x_{off_2}
+ * \f}
+ * |
+ *
+ *
+ * Joint to actuator
+ * |
+ *
+ * \f{eqnarray*}{
+ * \tau_{a_1} & = & \tau_{j_1} / (n_{j_1} n_{a_1}) \\
+ * \tau_{a_2} & = & \frac{ \tau_{j_1} + \tau_{j_2} / n_{j_2} }{ n_{a_2} }
+ * \f}
+ * |
+ *
+ * \f{eqnarray*}{
+ * \dot{x}_{a_1} & = & n_{j_1} n_{a_1} \dot{x}_{j_1} \\
+ * \dot{x}_{a_2} & = & n_{a_2} (\dot{x}_{j_1} + n_{j_2} \dot{x}_{j_2})
+ * \f}
+ * |
+ *
+ * \f{eqnarray*}{
+ * x_{a_1} & = & n_{j_1} n_{a_1} (x_{j_1} - x_{off_1}) \\
+ * x_{a_2} & = & n_{a_2} \left[(x_{j_1} - x_{off_1}) + n_{j_2} (x_{j_2} - x_{off_2})\right]
+ * \f}
+ * |