Hazard-free steer-by-wire in articulated heavy earth moving machinery using co-simulation model

The articulated Heavy Earth Moving Machinery predominantly use hydrostatic steering, because of its reliability and redundancy. In earlier studies an energy efficient Electro-Hydrostatic Steering System was proposed, which works on Steer-by-Wire principle and comply with the safety standards. This paper presents co-simulation of a wheel loader model with hazard-free Steer-by-Wire. A co-simulation model using three software platforms; Mevea for multibody dynamics and mechanics, Simcenter AMESim for hydraulics, and MATLAB/Simulink for hydraulics, control, and data analysis, is created to analyse the hazard-free functionality of the steering. The simulation model of primary steering, which is an electric motor controlled Electro-Hydrostatic Actuator, is validatedexperimentally. In these heavy machines, as required by the standards there shall always be a secondary steering system for redundancy. The secondary steering, which is through a proportional control valve is modelled using the characteristics of the commercial product. There are five possible hazard scenarios in steering application of such machinery, which have been identified by the authors in earlier publication. These five hazard scenarios are realised in co-simulation model by modelling the respective faults in the primary steering, and the effectiveness of the hazard-free functionality in the steering is analysed. The study demonstrates that the novel Steer-by-Wire for articulated steering can effectively mitigate the potential hazards associated with steering in Heavy Earth Moving Machinery, moreover, co-simulation model provides an effectual mean to analyse the novel solutions.