Research On Steer-by-wire System Road Feel Analog Algorithm

Steer-By-Wire system is typical of substituting virtual control signals for actual mechanical linkages between the steering wheel and the road wheels.Benefiting from this unique design,plenty of tricky problems receive a quick answer.For instance,active steering,ideal road feel design,more efficient vehicle integration,etc.Thus,it makes significant sense to take a deep probe into the SBW system.This paper focuses on SBW road feel analog.To appeal to drivers that have already been accustomed to the conventional steering system,the road feel of SBW system is supposed to be as good as that of conventional steering as possible,which renders realistic and safe feel for the drivers.Main points of this paper:1.Deeply analyzed the principle of road feel.The alleged road feel is the reverse force feedback form the steering wheel when driving,which mainly results from roadtire interaction and inherent properties like inertia,damp and friction of the steering system.2.Designed a vehicle state observer to obtain critical parameters needed in the road feel algorithm and compared two road feels computed by the analog algorithm and a conventional way respectively.The proposed analog algorithm proved to be more robust and precise than conventional analog algorithms.Designed a road feel filter algorithm to improve handle of the driver by reducing vibration from the road bump.It turned out that the proposed algorithm is able to filter bad road interference with complete preservation of road conditions.3.Modified road feel algorithm referring to the way traditional steering systems realize ideal steering force according to characteristics of steering effort preference.Designed an adaptive returning algorithm using Proportional-Derivative control algorithm based on dual response targets,overshoot and settling time.Moreover,a CarSim-Simulink joint simulation model was built to verify the effect of the algorithm.4.Designed and built a Rapid Control Prototype test bench.Completed debugging of the software and hardware of the RCP test bench which mainly consisted of two parts: road feel analog algorithm based on CarSim-Simulink and hardware environment based on dSPACE.Validated feasibility of the algorithm by typical driving tests corresponding to the simulation results.