# Dynamic Modeling and Analysis of a Driving Passenger Vehicle
###### Abstract
Subsequently, the vertical vibration of the vehicle body according to the change in parameters such as mass, stiffness, and damping ratio in the model was analyzed through numerical analysis. [PERSON] et al. [12] presented an optimization technique for deriving optimum values of damping and stiffness of suspension for improved ride comfort with vehicle models, including manual and semi-active suspension. [PERSON] et al. [13; 14] established a model by additionally considering a seat and a human body in a quarter-car model that depicts only existing vehicles. They proposed a methodology to improve ride comfort through vibration responses from seats or body parts according to vertical road excitation. After that, the vehicle model was expanded from the existing quarter-car model to the half-car model to consider the tilting behavior of the car body. Some studies that analyzed ride comfort using this model are as follows: [PERSON] et al. [15] derived the equations of motion for a vehicle model with four degrees of freedom that can consider the bounce and pitch of the vehicle body traveling on a rough road. They analyzed various responses in the time and frequency domains for the change in model parameters. [PERSON] et al. [16] obtained frequency response functions for random road excitation through a vehicle model considering the pneumatically interconnected suspension (PIS) system and compared and analyzed them with the vehicle model without the PIS system. On the other hand, [PERSON] et al. [17] were interested in the roll behavior of the vehicle body. They established a vehicle model with the effects of the anti-roll bar and the control arm and presented a suspension control system that can control the roll of the vehicle body caused by road excitation. [PERSON] et al. [18] proposed an active anti-roll bar system that can effectively control the roll motion of the vehicle body caused by lateral acceleration under vehicle turning conditions. Recent studies analyzed the riding comfort of a full-size car model to better understand the behavior of the actual vehicle. [PERSON] et al. [19] proposed a full car model with seven degrees of freedom that can analyze ride comfort. To verify the validity of the proposedmodel, the similarity between the simulation and experimental results was shown in the pitch mode test condition of the vehicle body that occurs when passing through a bump. [PERSON] et al. (2018) and [PERSON] et al. (2018) established a full vehicle model with seven degrees of freedom considering active suspension and found that active suspension improves riding comfort by preventing vehicle resonance that may occur due to road excitation. On the other hand, [PERSON] and [PERSON] (2018) proposed a full car model with 14 degrees of freedom that can analyze the rolling behavior of a turning vehicle according to steering conditions. He also showed the limitations of his model and demonstrated its excellence and validity. On the other hand, vehicle dynamics can be analyzed by using commercial multi-body dynamics software packages such as ANSYS-Motion ([PERSON] _et al._, 2018), RecurDyn (2018), MSC/Adams (2018), and Simpack (2018). These commercial packages provide the advantage of easily constructing detailed vehicle models. However, they require a lot of experience and skill in constructing the model, assigning boundary conditions/constraints, and often requiring long computation times. On the contrary, concentrated mass models are difficult to apply to complex systems. However, it is relatively easy to analyze the influence of various parameters of the model and requires shorter computation times. With improvements in the road environment and recent developments in the vehicle industry, vehicle consumers are demanding improvements in ride comfort performance according to the driver's steering conditions rather than solely focusing on ride comfort performance against irregular road surface disturbances. In this regard, various vehicle manufacturers have attempted to analyze and improve ride comfort through driving tests.