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In this paper we researched the vehicle braking sense in three aspects of human, vehicle and environment and analysed their impacts on brake feeling. Through the real vehicle test we analysed the relationship among pedal force, pedal travel and deceleration. We used dynamometer test method to study the brake noise question. We designed a fixture which could imitate the suspension and made the test more close to the true level. Moreover we discussed how to establish the evaluation system of vehicle braking condition. Through real vehicle test of braking, we can test and record the brake system parameters in the braking process under urban working conditions. We recorded the brake frequency, the change of brake speed and brake disc temperature. Meanwhile, based on the analysis of braking condition, we put forward the index of brake load to reflect the city’s traffic conditions. Experiment show that the braking condition and brake feel are related, braking condition also provides theoretical support for the design of brake system.

Keeping a vehicle in its current lane without veering into adjacent lanes is important in hard-braking manoeuvres on split- μ roads. Whether the emergency braking is initiated by a human driver or by an AEBS, drivers have difficulty adjusting steering correctly to balance yaw moment generated by asymmetric tyre braking force. Some anti-lock braking systems reduce braking force to reduce the yaw moment, which will increase braking distance. To improve the stability in the abovementioned scenario, a feedback-feedforward steering controller is proposed in this paper. To describe the tyre force characteristics of combined slip and nonlinearity, a linear tyre model based on the total differential method is developed. The receding horizon linear quadratic regulator method is utilised to design the feedback steering input to drive state variables to zero in the finite domain. And fuzzy logic is developed to tune the weighting matrix. Furthermore, feedforward steering input is designed to suppress path tracking steady-state error. The performance of the proposed controller is illustrated by hard-braking manoeuvres experiments on normal split- μ and 'checkerboard' roads. [ABSTRACT FROM AUTHOR]

This paper proposes a hybrid suspension system, consisting of a linear electric motor (LM) and a semi-active mono-tubed magnetorheological damper (MRFD), to improve vehicle dynamics with lower power demand. For determining the damping force directly and concisely, a modified bi-viscosity magnetorheological fluid (MRF) model that explicitly includes the current parameter is developed. The fabricated LM and MRFD are calibrated and tested for validation of the implemented mathematical models. The simulation results show that the modified bi-viscosity model is able to calculate the experimental MRFD external forces very well. Thereafter, the hybrid suspension system is integrated into a 2-DOF (degree-of-freedom) quarter-vehicle dynamic model for simulation analysis, considering bump and pothole road profiles and the wheel bounce movements. Moreover, the two step-control methods, namely SC1 and SC2, are modelled for enhancing vibration mitigation and reducing power demand. The MRFD current influences on the root mean square (RMS) of the vehicle body vibration amplitudes are studied. Results reveal that the optimal MRFD current is ranged from 1 to 2.2A considering the SC1 method. Finally, the energy efficiency of the step-control methods is proved to be much higher than the PID method especially at low vehicle speed and in large road heave situations. [ABSTRACT FROM AUTHOR]