Simulation Analysis On Assist Characteristic Of EPS In Light Commercial Vehicle

The EPS(Electric Power Steering )system provide it's assist torque directly by the motor who is controlled by ECU. EPS is a new high-tech which follow modern automobile development ,can improve vehicle active safety ,save energy ,benefit the environment, and is easy to be modularized. At first EPS system was used in the car. As the improvement in science and technology, EPS system will be equipped in higher load commercial vehicle. so it is need to analysis the assist characteristic for the commercial vehicle equipped EPS. this article works in the following area:The architecture, principle and the current development of EPS are interpreted. the way to the judgments of steering system, the character of steering-torque and the'road feeling', the curve of perfect assist characteristic and some kinds of popular assist characteristics are recommended. the theory elements of the model―― multi-body dynamics, the tools used to establish model――ADAMS/car for the multi-body dynamic model and MATLAB/simulink for control model are recommended too.Refer to the EQ1061, a multi-body dynamic model of truck with front/rear leafsprings which are made of flexible body and front/rear dependent suspension is established. this paper detailed introduces the establish of the tample of front/rear dependent, front/rear leafsprings and steering system with EPS. And a full truck model which includes the front/rear suspension,front/rear leafsprings,steering system,front/rear wheel,powertrains,driveline and body is introduced too. And then, a kind of vehicle speed induction assist characteristic which doesn't sacrifice the steering maneuability at low vehicle speed and can obviously intensify the"road feel"at middle and high vehicle speed is given. A simulation is also launched.Front suspension parallel travel analysis and full vehicle line-drift test are launched to discuss the effect of transmutation steering and the model is improved.constant radius accelerate test is launched to research the steady character of the full vehicle model. Cornering w/wheel steer release test is launched to research the returnability. The lemniscates course test is launched to research the steering portability of EPS system. The result show that the full-truck model equipped EPS has a little understeer character, well returnability and steering portability, and the assist characteristic is reasonable.