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Driveline torque distribution has long been a research topic, and in the last several decades research has been directed towards enhancing on-road vehicle stability and agility through application of controllable driveline systems. This paper discusses the impact of Direct Yaw Control AWD systems (DYC AWD Systems) on the combined acceleration and turning performance as it pertains to maneuverability and stability on all road surfaces. To achieve higher levels of both safety and performance, the application of a controllable DYC AWD system capable of applying direct yaw moment to the vehicle chassis serves as a key goal to achieve the optimal result. A classification of existing driveline systems is discussed and compared to these optimal requirements. Representative on-vehicle scenarios are discussed to illustrate the impact of AWD control on the vehicle stability and maneuverability and to highlight the effects to the vehicle operator.

In order to advance vehicle stability control strategies and provide enhanced customer benefits, a methodology for combining the capabilities of an active driveline system capable of direct yaw control with a vehicle stability assist controller (also referred to as ESC, electronic stability control) has been developed. As a basis, the traditional ESC operation of using only brake and throttle control is compared and contrasted against customer needs and expectations. Using the existing ESC stability control system as a representative yaw stability control algorithm, the actuation capabilities of a controllable AWD system are arranged through a simple CAN communication scheme to serve as an available extension to the ESC actuator set (i.e. brake, throttle and now AWD direct yaw moment control). The ESC unit is allowed to request a rear axle torque amount change to the controllable AWD unit ECU.

Research pertaining to electronically controllable AWD (All Wheel Drive) systems continues in the automotive industry as a means to further enhance vehicle traction, maneuverability, handling and stability characteristics. Different feed-forward and feedback control approaches have also been explored to enhance AWD system performance and robustness under various vehicle operating conditions. Due to the large variability of vehicle operational conditions, some trade-off usually needs to be made to achieve a balanced overall-AWD system performance, especially traction and maneuverability for both normal flat roads and hill climbing conditions. The purpose of this research is to develop a hill grade detection method and strategy for application in vehicle front to rear drive torque distribution control to enhance AWD system robustness while climbing low-mu hills. First, an overview of existing vehicle hill climbing related drive torque control approaches are presented.

This paper presented an engineering review on the state of the art in the research and development of vehicle-trailer handling dynamics and stability controls. The issues and potential technical solutions were identified in various areas and the unique characteristics of vehicle-trailer as a combined system were investigated and compared to a single-unit vehicle system. Many approaches taken in modeling, analysis, simulation and testing were examined, and various control methods, actuations and control implementations were evaluated. As a result of this study, further research areas were also identified. While it is important to maintain the stability of a trailer, thus the stability of a vehicle-trailer combination, it remains one of the major challenges in designing an appropriate control law to balance effectively the requirements between stability and handling performance, which often set conflicting objectives.

This paper presents a visual simulation method for vehicle ride comfort evaluation. First, a 3D vehicle virtual prototyping model is built using ADAMS. With totally 596 degrees of freedom, this model incorporates every major factor that influences the vehicle ride comfort. Based on the virtual model, time domain simulations on random road inputs are further carried out and the vehicle dynamic characteristic parameters are obtained. Then, referencing a real proving ground, a ride comfort testing graphics database that contains road surfaces, rivers, grass, houses, trees, cordilleras and so on, is developed. After setting and programming resources such as graphic frame buffer, channel, scene, light, camera facility, a virtual proving ground that is able to simulate the real world, real color, and light is established. Finally, OpenGVS SDK program tool is used to call virtual proving ground and vehicle model database.

For stability control on a vehicle-trailer combination, the coupling between vehicle and trailer as two pivoted rigid bodies has been investigated, in view of concerns that the coupling strength varies as vehicle-trailer parameters change, and thus plays an important role in the design and robustness of the stability controller. Analyses through root locus and time-domain response have been conducted and several observations have been made, which are valuable for the controller design. A preliminary stability controller with state feedback has been designed and simulated to further verify the studies above.