The axis model consists of the controller, the motor including current controller and the gearbox including gear elasticity and bearing friction. The only difference to the axis model of joints 4,5,6 (= model axisType2) is that elasticity and damping in the gear boxes are not neglected. The component States is a dummy inertia, i.e., the inertia is zero, to define that the absolute angle and the absolute angular velocity of the driven gear flange are used as states.
The input signal of this component is the desired angular acceleration of the joint (= reference acceleration). From the acceleration, the reference position and reference velocity are computed via integration. The reference input is an acceleration, because the reference signals have to be "smooth" (position has to be differentiable at least 2 times). Otherwise, the gear elasticity leads to significant oscillations which are not acceptable.
Default values of the parameters are given for the axis of joint 1.