Direct current measurement based steer-by-wire systems for realistic driving feeling

In this paper, a method to reproduce realistic driving feeling and improve the returnability of steer-by-wire systems (SBW) is proposed by measuring the roadwheel motor´s current directly. The key contribution presented here is a novel method to recreate the driving feeling in term of force feedback with simple and cheap current sensors. A current sensor is used to fully measure the steering torque on the rack of steering mechanism. This measured steering torque therefore, includes the overall effects of road conditions, aligning moments, tire properties and so on. Beside that, a free control scheme is proposed to improve returnability as well as the handwheel stability in a free motion. Moreover, during this research, the significant frequency effect of handwheel motions was found. This effect could be useful and valuable for improving steer-by-wire development based on torque-map based method. This method is investigated with simulation results using the control design and simulation module in LabVIEW programming language. The simulated results show that this method offers a cheaper and simpler solution for the development of steer-by-wire systems. In addition, stability and returnability of handwheel in steer-by-wire systems could be improved.