Analysis And Parameter Matching Of Handling Stability For Heavy-duty Truck

For the heavy-duty truck always continuously running at a high speed and heavy loading, the vehicle will be out of control if it could not follow the driver's control purpose. So the heavy-duty truck manufacturers and users pay more attention to the vehicle handling stability. How to improve the vehicle handling stability has been a focus pursuing goal for the automobile manufacturers and research institutes.This paper was completed based on the project"State High-tech R&D Plan (863 Plan) of China"(2006AA110105)supported by a domestic auto manufacturer. This paper built a virtual prototype model of heavy-duty truck by using MSC.ADAMS software. The truck subsystems such as suspension, steering system, engine system and tire were built in ADAMS software, and these subsystems were assembled in the test rig of ADAMS/car into a full truck. The data are transferred between the subsystems and test rig by communicator.In accordance with National Standard"GB/T6323.3-94～GB/T6323.6-94 Controllability and stability test procedure for automobiles", Steering transient response simulation (Steering wheel angle pulse input), Returnability simulation, Steady static circular simulation and Steering efforts simulation were performed in ADAMS software environment. The validity of the model was verified by comparing the simulation result with corresponding experiment data of the tests. The test and simulation results were evaluated based on"QC/T480-1999 Criterion thresholds and evaluation of controllability and stability for automobiles". The results show that the vehicle steady- state steering characteristic was under-steer and it had good transient response, steady- state steering and steering efforts performance. But the returnability performance was not good. In generally, the vehicle handling stability performance was ok. But there was still a need to be upgraded.The frame and cab experienced a greater deformation when the vehicle was running. Their elastic properties can't be reflected truly if they were considered as rigid bodies. In order to study the influence of the elastic bodies to the vehicle handling stability, this paper built finite element models of the frame and cab. At last, a rigid-elastic coupling model was built. Some simulations were performed in ADAMS software environment to analyze the performance of the vehicle controllability and stability. The comparison results show that the rigid-elastic coupling model was more accuracy.The sensitivity of the coordinates of the hard points in front suspension was calculated using ADAMS/Insight and six coordinates which had more influence on the vehicle handling stability performance were optimized. After optimization, in accordance with National Standard GB/T6323.6-94 "Controllability and stability test procedure for automobiles—Steady static circular test procedure", a steady static circular simulation was performed in ADAMS software environment. The comparison results indicated that the optimal vehicle model had a better handling stability performance than the initial one.On the basis of front suspension optimization, the sensitivity of the coordinates of the hard points in middle and rear suspension was calculated using ADAMS/Insight and six coordinates which had more influence on the vehicle handling stability performance were optimized. After optimization, in accordance with National Standard GB/T6323.6-94 "Controllability and stability test procedure for automobiles—Steady static circular test procedure", a steady static circular simulation was performed in ADAMS software environment. The comparison results indicated that the optimal vehicle model also had a better handling stability performance than the initial one.On the basis of suspension optimization, the sensitivity of the main whole vehicle parameters was calculated using ADAMS/Insight and eight parameters which had more influence on the vehicle handling stability performance were optimized. After optimization, in accordance with National Standard GB/T6323.6-94 "Controllability and stability test procedure for automobiles—Steady static circular test procedure", a steady static circular simulation was performed in ADAMS software environment. The comparison results indicated that the optimal vehicle model still had a better handling stability performance than the initial one. In sum, a conclusion can be draw. The optimization had improved the handling stability performance of the model to some extent.