# In-Field Load Acquisitions on a Variable Chamber Round
## 3 Load Acquisition Results and Discussion
### Load Identification
Figure 12: Vertical loads F\({}_{\text{v}}\)(t) acting on the L and R hub carriers of the round baler during a _product collection_ maneuver: (**a**) whole acquisition, (**b**,**e**) product collection, (**c**) headland turning, (**d**) GPS route, (**f**) effect of the baler’s rear door opening on the L and R hub carriers, and (**g**) effect of starting the PTO on the R hub carrier. Figure 14a reports the horizontal loads F\({}_{\text{h}}\)(t) registered by the dynamometric towing pin during an _acceleration followed by emergency braking with a loaded baler_. The acceleration and braking phases were performed by towing the baler parallel to the sowing lines, as indicated in Figure 14b. The peak loads registered during the acceleration and braking phases were \(-26.6\) kN and \(+41.5\) kN, respectively. The braking phase was completed in approximately two seconds, during which the baler decelerated from 32 km/h to 0 km/h. This corresponded to an average deceleration, intended as \(\Delta v/\Delta t\), of 0.45 g with an initial peak of about 0.96 g at \(t\) = 86.8 s.  
Figure 15 reports the vertical loads F\({}_{\text{v}}\)(t) acquired by the L and R hub carriers while running perpendicular to the sowing lines. It is worth mentioning that the maximum and minimum loads registered by the hub carriers came from this maneuver. In particular, the R hub carrier registered a force of \(+38.8\) kN at t = 75.4 s (indicated by a blue arrow in Figure 15b), while the L hub carrier registered a force of \(-4.68\) kN at t = 75.8 s (indicated by a red arrow in Figure 15b). These values represent the highest and lowest measured forces obtained in all acquisitions. A negative force on the hub carrier correspond to the event in which the baler's tire loses contact with the ground, meaning that at t = 75.8 s the L hub carrier registered a negative dynamic load that was approximately 3.8 times higher than the minimum static load of--1.24 kN (see Figure 4a) corresponding to the weight of one baler's wheel. The maximum and minimum loads registered by the hub carriers during this maneuver are reported again in Table 4. Furthermore, it can be noted that the time variant loads reported in Figure 15 are similar to the ones reported in Figure 12c while performing _headland turning_ with the baler, also in that case, running perpendicular to the sowing lines. The higher vertical loads reported in Figure 15 in respect to the loads registered in Figure 12c can be explained by looking at the speed signals, with the baler's average speed being approximately two times higher in Figure 15 than in Figure 12c. Figures 16 and 17 present two different portions of the signals acquired at the L and R hub carriers during _road transportation_. Figure 16 presents the overload effect of a manhole taken by the R hub carrier while running at a constant speed of approximately 20 km/h. This phenomenon causes a force range of 15.4 kN. Similarly, in Figure 17, the effect of an asphalt trench perpendicular to the road crossed at a higher speed of approximately 30 km/h is visible. In this case, a greater force range of 17.8 kN was measured on the R hub carrier. Figure 13: (**a**,**b**) R hub carrier signals from Figures 12f and 12g, respectively, presented in the frequency domain. Figure 14: Horizontal loads \(\mathrm{F_{h}}\) (t) registered by the dynamometric towing pin during _acceleration followed by emergency braking with a loaded baler_: (**a,c**) force and speed signals and (**b**) straight path followed by the baler. Figure 15: Vertical loads \(\mathrm{F_{v}}\)(t) acting on the L and R hub carriers of the round baler during _high-speed running perpendicular to the sowing lines_: (**a**) whole force and speed signals and (**b**) details of the signals, with the maximum load \(\mathrm{F_{vmax}}\) acting on the R hub carrier and the minimum load \(\mathrm{F_{vmin}}\) acting on the L hub carrier marked by blue and red arrows, respectively.