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Feedback through the steering wheel is known as the most important source of information to the driver. The so-called steering feeling, composed of self-aligning actions coming from tyres and suspension geometry all the way through mechanical linkages to the driver's hands, provides vital communication for intuitive driving, and it is therefore utterly important for safety and for a pleasant driving experience as well. Subtle forces and vibrations, due to the interaction between the tyre contact patch and the road surface texture, also play a role, provided they are not heavily filtered or cancelled by the power steering system. Human perception is guided by experience in order to establish correlations between steering feedback and vehicle motion in terms of straight-line stability, cornering speed, tyre adhesion and available friction, vehicle balance, and so on. A front-wheel drive car is potentially a critical vehicle from this point of view, especially when the powertrain can deliver large torque figures, and even more so if a limited-slip differential (LSD) or a similar active device is present in order to improve traction capabilities. Any difference between the two wheels in terms of tractive force can result into the so-called torque steer issue, that is to say, a "pulling" sensation on the steering wheel or a shifting of the vehicle from the desired trajectory. This paper analyses the torque steer phenomenon on an all-wheel-drive, full electric sportscar where a significant portion of the torque is transferred to the front axle. The effects of suspension kinematics and the load variation at tyre contact patch level are taken into account. For evaluating the impact of steering feedback, the VI-grade® simulation software is adopted and a test campaign on the professional driving simulator available at the University of Brescia has been carried out in order to understand the impact of steering feedback on driver perception and performance. [ABSTRACT FROM AUTHOR]

To improve the steering feeling at high speed and reduce the energy consumption of power steering system for heavy-duty commercial vehicles , a novel electronically controlled hybrid power steering system ( ECHBPS) with assist torque coupling device was proposed based on the electro¬hydraulic steering system. The structures and working principles of ECHBPS were introduced , and the parameters of hydraulic subsystem were reset to reduce the steerng system energy consumption. The assist characteestic cures of the electrical and hydraulic subsystems were designed according to drver preferred manoeuvrng torque at different speeds , and the model of ECHBPS energy wastage was established. The co-simulation of Matlab/Simulink and Trucksim was conducted. The results show that compared with the hydraulic power steerng system ( HPS) , the steerng portability of ECHBPS is improved by 21. 3% under the parking manoeuvrng condition , and the steerng feeling under the oncenter steering condition is improved by 108. 96% . The energy consumption values are reduced by 15. 74% under the steering condition and by 62. 61% under the straight-driving conation, respectively. [ABSTRACT FROM AUTHOR]

Feedback through the steering wheel is known as the most important source of information to the driver. The so-called steering feeling, composed of self-aligning actions coming from tyres and suspension geometry all the way through mechanical linkages to the driver’s hands, provides vital communication for intuitive driving, and it is therefore utterly important for safety and for a pleasant driving experience as well. Subtle forces and vibrations, due to the interaction between the tyre contact patch and the road surface texture, also play a role, provided they are not heavily filtered or cancelled by the power steering system. Human perception is guided by experience in order to establish correlations between steering feedback and vehicle motion in terms of straight-line stability, cornering speed, tyre adhesion and available friction, vehicle balance, and so on. A front-wheel drive car is potentially a critical vehicle from this point of view, especially when the powertrain can deliver large torque figures, and even more so if a limited-slip differential (LSD) or a similar active device is present in order to improve traction capabilities. Any difference between the two wheels in terms of tractive force can result into the so-called torque steer issue, that is to say, a “pulling” sensation on the steering wheel or a shifting of the vehicle from the desired trajectory. This paper analyses the torque steer phenomenon on an all-wheel-drive, full electric sportscar where a significant portion of the torque is transferred to the front axle. The effects of suspension kinematics and the load variation at tyre contact patch level are taken into account. For evaluating the impact of steering feedback, the VI-grade® simulation software is adopted and a test campaign on the professional driving simulator available at the University of Brescia has been carried out in order to understand the impact of steering feedback on driver perception and performance.

The research discussed in this paper proposed a control method that imparts equivalent friction to electronic power steering (EPS) systems in order to improve the steering feel. In order to impart friction stably, the proposed method uses motor torque rather than mechanical elements to impart friction. First, the effect of friction on the steering system was considered theoretically using simple harmonic motion models, and it was demonstrated theoretically that steering responsiveness could be increased by imparting appropriate friction force to the steering system. Based on the results of this analysis, a target value for equivalent friction force to be imparted by means of EPS control system was formulated. A method of linear approximation of the friction force necessary to realize equivalent friction force based on this target value was proposed. The method was applied in an actual vehicle, and the EPS system configuration necessary for the desired effect to be obtained was examined. It was considered that a system configuration incorporating a steering torque sensor with high torsional rigidity would be necessary, and a control method for imparting equivalent friction force was proposed. Finally, the effectiveness of the proposed method was verified in simulations using a vehicle model and in tests involving an actual vehicle. The vehicle model simulations demonstrated that the application of the proposed method increased steering responsiveness. The vehicle tests verified that the proposed method made it possible to obtain a stable steering feel, and was also effective in improving steering feel.