# In-Field Load Acquisitions on a Variable Chamber Round
## 2 Research Methodology
### Testing of the System  
Table 1 reports the maneuvers performed, the number of acquisitions carried out for each maneuver, and the total duration of the acquisitions, where any downtime was excluded. The baler settings are presented in Table 2, where the baler and PTO rotation speeds can be seen along with the blade settings and the desired bale diameter. Retracting the blades allowed to reach higher baler speeds, while the desired bale diameter was set to its maximum to achieve the heaviest possible bale. Figure 8: Relationship between the horizontal loads \(\mathrm{F_{h}}\) measured by the strain gauge channels versus the horizontal loads \(\mathrm{F_{exp}}\) applied by the servo-hydraulic actuator. Figure 7: Experimental relationships between the \(\varepsilon_{\mathrm{PUSH}}\) strains returned by the upper and lower half bridges and the lever arm \(b\): **(a)** pulling configurations, **(b)** pushing configurations. The acquisitions were carried out with a variable chamber round baler having an unladen weight of 3940 kg, and were performed during the summer in a field located in northeastern Italy. The harvested product was corn stalks. The _product collection_ acquisitions were initiated with an empty baler. In each acquisition, a single round bale was collected, tied, and unloaded. The _acceleration followed by emergency braking_ acquisitions, both with a loaded and an empty baler, included an initial acceleration phase up to approximately 30 km/h and a subsequent braking phase. The _high-speed running perpendicular to the sowing lines_ acquisition was performed without collecting product and with an empty baler at a nominal constant speed of 12 km/h. The _road transportation_ acquisition was conducted on asphalt with an empty baler, and 4.31 km were covered at an average speed of 17.3 km/h. The maximum speed reached was 34.7 km/h. It is worth mentioning that in all the above presented maneuvers, the acquisitions were started and stopped with the baler at a standstill. During the execution of the maneuvers, the signals coming from each hub carrier and from the dynamometric towing pin were acquired through an IMC CS-7008-FD Data Acquisition system equipped with eight analog channels (imc Test & Measurement GmbH, Berlin, Germany). The sampling frequency was set to 200 Hz, which was appropriate to capture the phenomena which the baler underwent during usage, and an anti-aliasing filter (AAF) was also activated. Additionally, video signals from a GoPro Hero 10 Black (GoPro, San Mateo, CA, USA) (1080p, 30 fps) and the instantaneous speed, latitude, and longitude coordinate signals from a Garmin GPS18x-5 Hz (Garmin, Olathe, KS, USA) (sampled at 5 Hz) were acquired. Subsequently, the obtained data were downloaded via Wi-Fi and post-processed using IMC Studio(r) 5.2 and IMC FAMOS(r) Enterprise 2023 software. Specifically, a Butterworth low-pass filter with a 15 Hz cut-off frequency was applied in the post-processing phase. Regarding the vertical load acquisitions, prior to each acquisition session, the strain gauged channels of the hub carriers were zeroed with the baler and the tractor standing on flat asphalt. This was done because, even if the balancing procedure was already carried out during the calibration of the hub carriers' channels, it was the Authors' choice to repeat the balancing procedure every time the IMC CS-7008-FD data acquisition system was shut down. Therefore, only the sensitivity previously obtained (i.e., \(-25.3\)\(\mu\epsilon/\)kN and \(-22.5\)\(\mu\epsilon/\)kN for the L and R hub carriers, respectively) and reported in Figure 4b,c was maintained. By doing so, only the dynamic component of the in-field loads acting on the hub carriers was acquired during each acquisition. The corresponding static load