# Accelerometer-Based Pavement Classification for Vehicle Dynamics Analysis Using Neural Networks
## 3 Results  
The impact of various pavement types on vehicle vertical acceleration was examined, emphasizing their effect on vehicle dynamics, especially unsprung mass. Accelerometer data were used to examine several surfaces, each generating distinct acceleration patterns influenced by their unique physical features, which impact the vehicle's comfort, stability, and mechanical integrity. The experiment's findings demonstrate how varying textures and imperfections of surfaces result in distinct vertical strains inside the vehicle suspension, offering significant insights regarding pavement categorization. Figure 1 illustrates the acceleration of the vertically suspended mass as measured by the accelerometer while the vehicle traversed a grate-type surface. The characteristics of this surface induce very intense and frequent vibrations, as seen by the graph displaying acceleration peaks fluctuating between +150 m/s2 and \(-\)100 m/s2. This surface produces quick oscillations that significantly influence the vehicle's dynamics, particularly its unsprung mass (wheels and suspension), owing to the pronounced and regularly varying irregularities. Initially, Figure 1 shows an acceleration around zero (up to about 0.2 s), suggesting that the vehicle is either commencing movement or traversing a far smoother surface prior to reaching the grating. At 0.3 s, pronounced and frequent changes in acceleration are evident, plainly indicating surface irregularities. The most significant accelerations reach +150 m/s2, indicating substantial vertical pressures exerted on the vehicle's sprung mass. This coating substantially influences the vehicle's comfort and stability. Figure 1 indicates that the driver would have significant pain due to the extreme vertical acceleration, while the car's suspension would be perpetually exposed to substantial stresses. Such variations may lead to accelerated deterioration of suspension systems and wheels, as well as impacting driving safety. Figure 2 indicates that after 0.9 s of acceleration, the peaks diminish and stabilize, suggesting that the vehicle has transitioned from a \"grating\" surface to a smoother terrain or has decelerated. Consequently, the \"Grater\" surface induces abrupt and intense oscillations, which are clearly evident in the graph, and these findings suggest that this coating is among the most irregular used in the experimental analysis. Figure 3 illustrates a \"thump\" surface, characterized by greater but less frequent irregularities. This surface type is marked by infrequent but significant changes in the vehicle's dynamic behavior. In contrast to a grater surface, where vibrations are consistent  
Figure 2: The acceleration profile of vertically sprung mass on a grater-type surface: (**a**) the acceleration graph; (**b**) an example of the surface. and frequent, acceleration fluctuations here occur sporadically when the wheels traverse a succession of discrete bumps. At the start of Figure 3 (0 s), minor, consistent oscillations are seen, perhaps indicative of the vehicle traversing minor irregularities or transitioning onto a surface characterized by abrupt \"thump\" bumps from a smooth terrain. Initial significant increases in acceleration transpire within around 0.1 s when the wheels contact a substantial bump, yielding an acceleration value of approximately +200 m/s\({}^{2}\). Figure 3 illustrates a sequence of significant fluctuations, each characterized by distinct peaks as the acceleration varies dramatically. A secondary peak emerges at around 0.25 s, exhibiting acceleration values reaching +300 m/s\({}^{2}\), indicating a substantial or intensified perturbation on the surface to which the vehicle's sprung mass responds. Following each peak, the vertical acceleration rapidly declines, often reaching almost \(-\)100 m/s\({}^{2}\) or lower, indicating significant oscillations in the sprung mass as the wheels descend off the bump.