_Applied_  
_sciences_  
_Article_  
**Stability Tests of Agricultural and Operating Machines by Means of an Installation Composed by a Rotating Platform (the \"Turntable\") with Four Weighting Quadrants  
**[PERSON]**\({}^{\star}\)\({}^{\copyright}\) and **[PERSON]**\({}^{\copyright}\)  
Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Universita 5, I-39100 Bolzano, Italy; [EMAIL_ADDRESS]  
\({}^{\star}\) Correspondence: [EMAIL_ADDRESS]; Tel.: +39-0471-017181  
Received: 2 April 2020; Accepted: 26 May 2020; Published: 29 May 2020  
**Featurered Application: This study describes the possible outputs of a novel test rig having an inclinable and rotating turntable, illustrating in detail the physical laws governing the phenomena. This rig can be successfully used to test the stability of real-scale vehicles in many operative conditions.**  
**Abstract: The stability of agricultural machines, earth-moving machines, snow-compaction machines and, in general, of all vehicles that may operate on sloping terrains is a very important technical feature and should not be underestimated. In fact, it is correlated, above all, to the safety of the operators, but also to the preservation of the structural integrity of these vehicles, to the prosecution of the activities and to the preservation of the economic investment. Although these facts are well-known, the international legislation and technical standards do not yet have a sufficient level of detail to give an all-inclusive quantification of the stability of the vehicle under examination in all its working conditions, e.g., at different inclination angles of the support surface, at different climbing angles of the vehicle on the slope, with different tires and inflating pressures, and on different terrains. Actual standards limit the stability tests to the experimental measurement of the lateral rollover angle only. Furthermore, the realization of unconventional test equipment able to widen the usually-tested scenarios could not be simple, due to the necessary size that such equipment should have (to perform tests not in scale) and to the related difficulties of handling full-scale vehicles. This work illustrates the applications of a new rig for testing the stability of vehicles, able to address all the above-illustrated issues and of possible future adoption to certify the stability performance of machines and perform homologous. This installation, named \"rotating platform\" or \"turntable\", has the peculiarity of being able to move the machine positioned on it according to two rotational degrees of freedom: (1) overall inclination of the support plane, (2) rotation of the support plane around an axis perpendicular to the plane. The same installation is also designed to record the weight supported by each wheel of the machine placed on it (by means of four sensorized quadrants), both when the platform is motionless and while the above-described movements of tilt and rotation are being carried out, thus locating precisely the spatial position of the vehicle center of gravity. The presented physical-mathematical models highlight the great potential of this facility, anticipate the outcomes of the recordings that the experimenters will have at disposal when the test rig will be effectively active, and help the future understanding of trends of data, thus maximizing the available information content.  
**Keywords: static stability test; stability of machinery; stability on sloping grounds; tilting platform; rotating platform; turntable; incipient rollover; Euler angles; roll angle; pitch angle; yaw angle**