# In-Field Load Acquisitions on a Variable Chamber Round
## 4 Conclusions  
The load spectra acting in the vertical direction on the hub carriers and in the horizontal longitudinal direction on the drawbar of a trailed variable chamber round baler were evaluated. To measure the external loads acting vertically on the hub carriers, the housings of the hub carriers were instrumented with properly calibrated strain gauge bridges. Similarly, the horizontal longitudinal loads were measured by strain gauging a dedicated towing pin. In both cases, the strain gauge channels were calibrated in the laboratory and allowed to measure the loads acting on the baler both under normal use conditions and under extreme events. The load signals were acquired during the execution of five maneuvers: _(i)_ product collection, _(ii)_ acceleration followed by emergency braking with the baler loaded with product, _(iii)_ acceleration followed by emergency braking with the baler unloaded, _(iv)_ high-speed running perpendicular to the sowing lines, and _(v)_ road transportation. Moreover, the synchronous acquisition of a video via an onboard camera and a GPS signal assisted the interpretation of the acquired signals. Finally, the load spectra obtained for each maneuver were evaluated according to ASTM E1049-85. The obtained results can be summarised as follows:  
* The use of instrumented hub carriers and a dynamometric towing pin allowed the measurement of external vertical and horizontal loads, respectively, during in-field load acquisitions, while maintaining the original structural components of the baler. * The specially designed towing system equipped with a dynamometric towing pin instrumented with strain gauges was calibrated with laboratory tests and average errors lower than \(\pm\)6.5% in the range from 10 to 40 kN were assessed. * The maximum and minimum vertical and horizontal loads were measured during the maneuvers. As to the dynamometric towing pin, the peak horizontal load was obtained during _emergency braking with a loaded baler_ and it was found to be +41.5 kN. Conversely, the peak horizontal load in the opposite direction was obtained while running at approximately 12 km/h across the sowing lines and it resulted in \(-\)33.7 kN. The maximum and minimum vertical loads on the hub carriers were recorded during the same maneuver, and the left hub carrier recorded +35.9 kN in the upward direction and \(-4.68\) kN in the downward direction, while the right hub carrier measured +38.8 kN and \(-1.70\) kN. The static load component at the hub carriers with the baler configured for the _high-speed running perpendicular to the sowing lines_ was found to be +14.3 kN and +13.8 kN for the left and right hub carrier, respectively. * The load spectra obtained from approximately 3300 s of data acquisition were derived. More than 10,000 load cycles acting on the hub carriers and on the dynamometric towing pin were acquired during the product collection maneuvers. Similarly, more than 5000 load cycles were obtained during road transportation. Furthermore, the amplitude-only load spectra of each maneuver and the sum of them for the recorded time mix were calculated. The amplitude-only load spectra, to be combined with the appropriate road mix and to be extended to the target design mission, represent helpful data to guarantee the targeted mission life of the baler. Conceptualization, G.M. ; methodology, G.M. and F.C. ; investigation, F.C. ; resources, G.M. and A.R. ; data curation, G.M., A.R. and F.C. ; writing--original draft preparation, F.C. ; writing--review and editing, G.M., A.R. and F.C. ; formal analysis, G.M. ; funding acquisition, G.M. All authors have read and agreed to the published version of the manuscript. This research was funded by UNISMART, grant number--Rep. n. 136/2023--Prot. n.2530. Not applicable. The data will be made available upon request. Maschio Gaspardo S.p.A. is gratefully acknowledged for supporting this research. Author [PERSON] was employed by the company Maschio Gaspardo S.p.A.