Study On Virtual Test Of Vehicle Ride Comfort

Ride comfort is one of the prime performances of modern vehicle. The newly developed vehicle must be evaluated and tested before entering into market. The traditional evaluation method is to build the vehicle model with mathematical differential equation, then pre-evaluate its comfort performance in the frequency domain. All the conclusions are interpreted and expressed in curve and data, which is invisual and lack of interactivity. As rapid progress of computer technology and application of virtual reality technology, we can create a 3D vehicle model and a virtual proving test rig in the computer, make the vehicle model run on the virtual testing road, then evaluate its performance. In another word, we can complete the ride comfort testing in computer during the period of product designing, experiencing the testing procedure, thereby the cost on developing and research will be minimized. Based on virtual testing technology of vehicle ride comfort, this dissertation focused on the procedures of setting up the desktop comfort virtual testing system, building ride comfort dynamics analysis model, completing ride comfort testing in virtual ground, etc.In this dissertation, two methods were adopted to build dynamics model for vehicle ride comfort analysis: one is eight freedom vehicle ride comfort differential equation model in which lateral movement of driver and vehicle body was considered. Combined with time domain model of random road input, we got the driver and vehicle's moving displacement. The other method, we built a Forland truck virtual prototyping using ADAMS, it is a 3D machine model, totally with 596 freedom degrees, every factor that influences the vehicle ride comfort was considered, finally complete the time domain simulation on random road input.We build a ride comfort testing graphics database regarding real proving ground, which contains the objects, e.g. road surface, river, grassland, house, trees, cordillera and so on. After setting and programming resource such as graphic frame buffer, channel, scene, light, camera facility, we built the virtual proving ground, which simulated the real word, real color, and light. Vehicle model database and virtual proving ground was called by OpenGVS SDK program. When the model running on the virtual road, it can show the vertical, lateral and pitching movement of the vehicle body and driver, and the rotation movement of the six wheels, these movements were controlled by model analysis data. Therefore, the vibrating displacement of vehicle was displayed in computer screen.This paper also presented virtual testing data recurrence system based on virtual instrument technology, which can recur the movement graphics as data and curves. Comparing with data obtained from real road testing, the result proved that virtual testing was reliable.