Study On The Evaluating System For Stability And Ride Comfort Of Vehicle

Along with the development of automotive technology all over the world, the position of automotive industry in national economy is arising. The large sales of automotive products make the transport equipment manufacturing industry be the third largest industry, only below the Oil industry and the electronic industry among the 20 major industries, which become the main driving force of economic growth. Since 1980s, CAD/CAE/CAM and other computer technologies have been applied in automotive field gradually. "Virtual development" gradually changes the traditional vehicle development process. During the whole process of vehicle development, comprehensive application of computer-aided technologies can save development costs by 30 percents or above and greatly shortens the vehicle development cycle. At the late of 1990s, computer technologies and application software development make the complexity of vehicle modeling increased more and more. Application of Multi-rigid-body system (Multi-Body System) dynamic analysis software, such as ADAMS, DADS makes the complex vehicle models be clearly expressed and be solved easily.Vehicle is a complex mechanical system, and its structure has many types. When applying virtual prototyping analysis software to do system dynamics and kinematics analysis, other relevant technologies are always integrated, in order to take advantage of the strengths of different analysis software.A vehicle of 6×6 independent suspension systems is chosen as the research object, which is composed of front suspension system, middle suspension system, and rear suspension system, and its driving form is six-wheel driving. Based on Multi-Body System dynamics and the simulation platform of ADAMS, according to vehicle modeling parameters of the three-axles vehicle of independent suspension systems, whole vehicle model which includes the following sub-models: front double wishbone independent suspension system, middle double wishbone independent suspension system, rear double wishbone independent suspension system, horizontal Stabilizer Bar, Steering System, Brake System , powertrain, front / rear wheels, and the vehicle body. Based on the vehicle model, some simulation analysis is carried out.The evaluation method and evaluation indicators of handleability, stability, and ride comfort are analyzed and collated. For handleability and stability, several common characteristics of handleability and stability are proposed, such as steady-state steering performance, transient steering characteristics, side-roll characteristics, vertical roll characteristics, turning-back steering characteristics, steering characteristics during a sharp turn, steering handiness characteristics, frequency response characteristics, and their corresponding evaluation indicators are given. For ride comfort, the simulation data processing method and evaluation method are introduced.Simulation on handleability and stability is carried out based on the vehicle dynamics model. According to the national standard of vehicle handleability and stability, several tests simulation are done, which include steering wheel angle-step input test, steering wheel angle-pulse input test, turning-back performance test, steady-state turning-back test, steering handiness test, snake-form test, double-line shift test, breaking during turning test. The evaluation indicators of the corresponding operation conditions are obtained.Simulation on ride comfort is carried out based on the vehicle dynamics model. According to the national standard of vehicle ride comfort, simulation analysis is carried out on the vehicle model, and the test data is processed. The acceleration Root-Mean-Square is chosen as the indicators of vehicle ride comfort.The main conclusions of the study are as follows:①.According to the simulation result analysis on handleability and stability which is based on the vehicle dynamics model, the researched vehicle has good handleability and stability.②.According to the simulation result analysis on ride comfort which is based on the vehicle dynamics model, the researched vehicle has good ride comfort on B-degree road and D-degree road of low speed, but has bad ride comfort on D-degree of high speed.