One mechanism is a six-bar linkage with a scissors kinematic. The second multibar system is a parallel linkage, or more specifically: a parallel-crank linkage. In both cases, a kinematic synthesis was used to find a solution, and the forces were then analyzed. From the forces, in turn, the necessary torques for both of the linkages can be determined. Additionally, it is shown how to implement forces that depend on the ladder position (extended or retracted) with the aid of scripts.
The corresponding ASOM project can be downloaded. It has been extended and now also shows a full comparison of forces.