Adaptive emergency braking control with underestimation of friction coefficient

Abstract

Abstract-In this paper, a control scheme for emergency braking maneuvers in automated highway systems (AHSs) and a new online identification scheme to determine the tire-road friction characteristics of the vehicle are presented. The proposed controller determines the required pressure in the master cylinder of the braking system to achieve maximum deceleration during braking, based on the estimation of the tire-road friction characteristics and the overall braking system gain, for the given set of parameter estimates. With persistence of excitation, the identified static map between the tire longitudinal slip and the tire-road friction coefficient is guaranteed to converge to the actual map. When there is no persistence of excitation, and under a proper choice of initial conditions and adaptation gains, the proposed scheme underestimates the maximum coefficient of friction and its corresponding slip, and allows a conservative calculation of the safety critical intervehicle spacing.

Adaptive Trajectory Tracking Control of Skid-Steered Mobile Robots

“…It has been widely considered that the friction coefficient μ is a function of the longitudinal slip λ [7], [13], [17]. Figure 3(a) shows the μ-λ curve that is obtained by fitting the experimental data [18]. Here, we consider a linear approximation of the μ-λ curve as shown in Fig.…”

Adaptive Sliding Mode Control of Adhesion Force in Railway Rolling Stocks

“…In addition, the adhesion force between the wheel and the contact surface is dominated by the initial braking velocity, as well as by the mass M and railway conditions. In the case of automobiles, which have rubber pneumatic tires, the maximum adhesion coefficient changes from 0.4 to 1 according to the road conditions and the materials of the contact surface (Yi, 2002). In the case of railway rolling stocks, where the contact between the wheel and the rail is that of steel on steel, the maximum adhesion force coefficient changes from approximately 0.1 to 0.4 according to the railway conditions and the materials of the contact surface (Kumar, 1996).…”

Intelligent exponential sliding-mode control with uncertainty estimator for antilock braking systems

“…In [3,4], a sliding-mode control (SMC) is designed to maintain the slip with parameter deviations and disturbances; however, the control law results in chattering control inputs so as to cause damage to ABS. In [5,6], a nonlinear adaptive control is proposed to obtain favorable control performance; however, it requires the structure of the system uncertainties. In [7], only three discontinuous control actions are allowed for ABS torque regulation.…”