## 3 Application of the Design Approach to the Definition of the Innovative Test Rig
### Design of the General System ('Test Rig')
#### 3.2.1 Conceptualization of the Mechanism(s) for Operating the System (\(\rightarrow\) Step 1.c)
Note that, according to the rigid movement of the platform around the articulation hinge, the end-point B of the platform has a horizontal translation toward the hinge as a result of the vertical lifting of the same point B; therefore, all the illustrated solutions have the capability of complying with this movement (all the above-described actuators generate a vertical thrust, freeing any horizontal movement of B). Figure 14: Summary of the process leading to the definition of the test rig configuration. It is also possible to evaluate some alternative configurations in which the hinging point A is released on the horizontal plane, and hence, in which the trajectory of the end point B is straight and vertical. In this way, the horizontal translation of the end-point B of the platform toward the direction of the hinge, which can be observed with the first solutions (Figure 15), is instead attributed to the other end of the platform, i.e., to the support point A (according to the kinematic inversion principle, see Section 3.4; Figure 16). Figure 15: Solutions providing for the inclination of the platform support-frame with a rotational movement: hydraulic actuator (**RVI**), winch and steel ropes (**RV2**; the pulley is supported by a properly-dimensioned fixed structure, not represented), threaded bar and nut (**RV3**; the threaded rod is supported by a properly-dimensioned structure, not represented; the connection between the nut and inclined plane is realized by means of a component, represented in the reported detail, able to freely move horizontally with respect to the nut to follow the displacement to the left of the end point of the tilting platform). In all the pictures, the decomposition of the vector \(v\) of the end point motion in the two components parallel to the coordinate axes is visible (\(v\) is constant in its magnitude but not in its direction). All the illustrated solutions have the capability of following the horizontal translation of the end-point B toward the articulation hinge as a consequence of the vertical lifting of the end B (B’ and B” are two different positions of the end point B). Therefore, the resulting movement of the tilting platform becomes that of rotation (around the point A, not fixed in space) and translation (horizontal shift toward the end-point B). Figure 16: Solutions providing for the inclination of the platform support-frame with a rotatory-translational movement: hydraulic actuator (**RTI**), winch and steel ropes (**RT2**; note that the pulley is supported by a properly-dimensioned fixed structure, not represented), threaded bar and nut (**RT3**). The end point B of the platform slides inside a rail fixed with respect to the reference system; the end point A moves to right (along a guide) as a consequence of the lifting of the end B. Note that the hydraulic jack and the threaded bar in their respective schemes are represented far from the vertical slider only for the sake of clarity, but these structures can be superimposed in the final design (a proposal is represented in the detail of RT1 where the slider is transparent). Another possibility to move the platform is represented by acting on the other component of the motion of the end-point B of the tilting platform (horizontal translation), with adequate thrust systems, thus causing the rotation of the same platform as the only kinematically-permissible motion. For example, this could be done through a horizontal hydraulic jack or by a threaded bar and a nut, both acting on a special thrust structure shaped as a vertical rail (Figure 17). The rail allows the vertical translation (in particular, upward) of the point B under the effect of a horizontal thrust.