# Dynamic Analysis and Seat Selection of Bus Driving Comfort under Different Road Conditions
## 6 Conclusions  
In this paper, from the perspective of rigid body dynamics, a motion differential equation suitable for bus driving was established by building a bumpy excitation road surface, and the mechanical response of the entire process on the road was analyzed. Secondly, based on the speed of the bus, the displacement and acceleration changes at different speeds were studied. Finally, the stiffness ratio of the front and rear wheels of the bus was analyzed. From these studies, the following conclusions can be drawn:  
(1) When a bus travels on uneven roads, the rear seats are more bumpy than the front seats. The reason for this phenomenon is that the center of gravity of the bus is closer to the rear wheels, the rear wheels bear more force and are more prone to displacement. This indicates that bus design should pay special attention to the damping of the bus backseat and control its displacement. Passengers who are \"old, weak, disabled, pregnant\",  
Figure 16: Net displacement and vertical acceleration \(2 ns\leq x\leq 2 ns+(b+c)\) (\(n\in N^{\bullet}\)) (The black line is the envelope of scattered points at low stiffness ratio; the red line is the envelope of scattered points at medium stiffness ratio; the blue line is the envelope of scattered points at high stiffness ratio).  
especially elderly people with osteoporosis, should avoid the seats at the rear of the bus as much as possible.  
(2) The bus should not drive too fast on uneven roads. For the simplified bus model and excitation pavement discussed in this paper, faster speed means higher displacement and acceleration variation, which is not conducive to passenger comfort. Regardless of the speed, similar displacements and accelerations will ultimately be achieved, but the speed is higher, and the duration of maximum displacement and acceleration is longer.  
(3) The spring stiffness ratio of the bus indicates that the bus is more stable when the rear wheels are high in spring stiffness. A bus model with low stiffness, whether climbing or downhill, will produce significant acceleration changes. During the manufacturing process of cars, it is better to ensure that the rear wheels have a higher stiffness coefficient, while appropriately reducing the stiffness of the front wheels.  
The results of this paper have certain significance. Engineers can use the differential equations and analytical solutions in this paper to roughly analyze the mechanical response of a moving bus by establishing an actual excitation road surface. These results can provide some guidance for the design and driving of buses. However, the impact of damping has been ignored in this paper. Damping can be taken into account in future bus models to more accurately analyze the mechanical response of buses during driving.  
Conceptualization, R.S. and J.W.; methodology, R.S.; software, R.S.; validation, Y.L. and R.S.; data curation, R.S.; writing--original draft preparation, R.S.; writing--review and editing, J.W.; visualization, Y.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Key Research and Development Program of China (Grant no. 2022 YFE0129100) and National Natural Science Foundation of China (Grant No. 51674246).  
Not applicable.  
The data used to support the findings of this study are available from the first author upon request.  
The authors declare no conflict of interest.