Received February 10, 2021, accepted March 22, 2021, date of publication March 24, 2021, date of current version April 7, 2021. Digital Object Identifier 10.1109/ACCESS.2021.3068949 Robust Control Framework for Lateral Dynamics of Autonomous Vehicle Using Barrier Lyapunov Function RAMEEZ KHAN , FAHAD MUMTAZ MALIK , NAVEED MAZHAR , ABID RAZA , RAJA AMER AZIM , AND HAMEED ULLAH College of Electrical Engineering and Mechanical Engineering, National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan Corresponding author: Rameez Khan (rameez.khan@ceme.nust.edu.pk) This work was supported by the National University of Sciences and Technology, Pakistan. ABSTRACT This article presents the robust lateral control of an autonomous vehicle in the presence of unknown lateral tire forces, road curvature angle, and parametric uncertainties. The sliding mode control (SMC) with barrier Lyapunov function is implemented to guarantee the system robustness while maintaining the outputs of the system in realistic bounds. Following the model reduction approach, the slow and fast dynamics of the system are separately controlled using the proposed control technique. The efficacy of the proposed control technique is examined by comparing the simulation results with conventional sliding mode control in two-time scales. INDEX TERMS Autonomous vehicle, barrier function, lateral dynamics, nonlinear model reduction, output constraints, single-input multi-output control, two-time scales. I. INTRODUCTION The development of autonomous vehicles has remained an interesting field of research for academia, the car manu- facturing industry, and other companies for the last three decades [1]. The autonomy of the vehicles is beneficial to society in several ways including passenger comfort, reduction in road accidents, and optimal fuel consumption. With the advancements in the development of autonomous vehicles, there are several challenges associated with it, including vehicle and passenger safety, fuel efficiency, and efficient maneuvering in different environments on different terrains [2]. The efficient maneuvering of the autonomous vehicle is of paramount importance, therefore significant research is being carried out to address the problems includ- ing vehicle stabilization in a cluttered environment, path tracking in presence of uncertainties and disturbances, local- ization, navigation, obstacle avoidance, and steering control while catering road bank angle and slippage etc. [3]–[7]. Path tracking control is a key concern for the autonomous vehicle during motion. The path tracking control enables the autonomous vehicle to track the desired trajectory by adjusting the lateral and longitudinal motion of the vehicle. The associate editor coordinating the review of this manuscript and approving it for publication was Luigi Biagiotti . In the car-like autonomous vehicle, the longitudinal dynamics become dominant when moving along the straight path while moving on the curved path, the lateral dynamics become more significant [8]. Autonomous vehicles require longitudinal and lateral control to achieve the desired path tracking [9]. The longitudinal control is to cater to the challenges of desired acceleration and operations of accelerating and braking of the vehicle [10]. On the other hand, lateral control deals with the challenges of safety, lane-keeping, lane changing, and achieving the desired lateral position [11], [12]. This article focuses on the robust control design for the lateral dynamics of the autonomous vehicle moving on the curve path. Lateral control for the autonomous vehicle has remained a challenging task for researchers due to the complicated lateral dynamics. Several studies are found in the literature to design the different control topologies for the autonomous vehicle lateral dynamics including LQR [13], PID [14], feed- back linearization [15] backstepping [16], [17], gain schedul- ing [18], sliding mode control (SMC) [19], [20], and fuzzy logic [21], [22]. The steering control for the autonomous vehi- cle using SMC and the backstepping controller is proposed in [19]. In [23] the sliding mode variable structure is adopted to control the lateral dynamics of the vehicle. The SMC in conjunction with gain scheduling and disturbance observer is presented in [24] for the vehicle path tracking. VOLUME 9, 2021 This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ 50513