A Study on the Effect of Structural Properties and Configuration of Low-Stiffness-Resilient-Shaft (LSRS) on Torsional Behavior

The use of the Low-Stiffness-Resilient-Shaft (LSRS) in the Semi-Active-Steering (SAS) system helps remove the drawbacks of the conventional and Steer-By-Wire (SBW) systems. However, the underlying structure of suitable configurations of LSRS which provide equal stiffness in both directions of twists have never been proposed before. This paper dealt with the modelling of LSRS using wire ropes and analysis of its torsional stiffness. Two potential design configurations of LSRS designated as config.1 and config.2 have been proposed. Finite Element Analysis (FEA) was carried out to determine their torsional stiffnesses. An experimental test rig (Torsion test machine) was also designed and fabricated and then it was used for the experimental validation of the simulation models. It was observed that config.2 had equal torsional stiffness in both directions while config.1 resulted in a slight error of 0.9%. In comparing simulation with experimental data, it was found that the maximum percentage error was about 12.41%, indicating the validity of the established model. The model and findings achieved from this research can be used to design an LSRS of required torsional properties which allows the steering to have equal torsional stiffness in both directions.