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S. Krishna

Bio: S. Krishna is an academic researcher from VIT University. The author has contributed to research in topics: Yaw-rate sensor & Control system. The author has an hindex of 2, co-authored 2 publications receiving 28 citations.

Papers
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Journal ArticleDOI
TL;DR: A fuzzy logic based yaw stability controller for an active front steering of a four-wheeled road vehicle by using steer-by-wire system is proposed and the results are compared with the existing fuzzy control system which uses two inputs such steering angle and yaw rate.
Abstract: Yaw stability control is an important consideration for improving the stability and handling behavior of a vehicle during extreme steering maneuvers This paper proposes a fuzzy logic based yaw stability controller for an active front steering of a four-wheeled road vehicle by using steer-by-wire system The proposed control system takes the yaw rate error, the steering angle given by the driver and the vehicle body side slip angle as inputs, for calculating the additional steering angle as output for stabilizing the yaw moment of the vehicle A three degrees-of-freedom vehicle model is considered Performance of the proposed system is simulated for sinusoidal, step maneuver using Matlab/Simulink tool, and the results are compared with the existing fuzzy control system which uses two inputs such steering angle and yaw rate The simulation results show better performance of the proposed fuzzy based yaw controller as compared with the existing control system

37 citations

Journal ArticleDOI
TL;DR: In this paper, a fuzzy logic based yaw stability controller is proposed to maintain the desired path of the vehicle, in presence of disturbances due to cross wind, different road conditions, and tire deflections.
Abstract: Yaw stability is an important consideration for the vehicle directional stability and handling behavior during emergency maneuvers. In order to maintain the desired path of the vehicle, in presence of disturbances due to cross wind, different road conditions, and tire deflections, a fuzzy logic based yaw stability controller is proposed in this paper. Proposed control system receives yaw rate error, steering angle given by the driver, and side slip angle as inputs, for calculating the additional steering angle as output, for maintaining the yaw stability of the vehicle. As the side slip angle cannot be measured directly in a vehicle, it was estimated using a model based Kalman observer. A two-degrees-of-freedom vehicle model is considered in the present work. The effect of disturbance on yaw rate and yaw rate error of the vehicle is simulated for sinusoidal, step maneuver and compared with the existing fuzzy control system which uses two inputs such as steering angle and yaw rate. The simulation results show better performance of the proposed fuzzy based yaw controller as compared with existing control system. Proposed fuzzy based yaw stability controller can be implemented in steer-by-wire system for an active front steering of a road vehicle.

5 citations


Cited by
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Journal ArticleDOI
TL;DR: This paper presents a tracking control method for the lateral motion of an autonomous land vehicle (ALV) based on active disturbance rejection control (ADRC) scheme and differential flatness theory, and the flatness of the linear model is proved and a flat output is found.
Abstract: This paper presents a tracking control method for the lateral motion of an autonomous land vehicle (ALV). This method is based on active disturbance rejection control (ADRC) scheme and differential flatness theory. The lateral motion is hard to control since it is underactuated, nonlinear, and with large uncertainties. By making a small-angle approximation, the dynamic model is linearized. The flatness of the linear model is proved and a flat output is found. An equivalent form of the model is obtained based on the flat output and its derivatives only. Moreover, an ADRC is adopted to guarantee both control accuracy and strong robustness. Simulation results are presented and the results show the effectiveness of the control strategies.

182 citations

Journal ArticleDOI
TL;DR: In this article, a three-layer hierarchical structure is proposed to coordinate the interactions among active suspension system (ASS), active front steering (AFS), and direct yaw moment control (DYC).
Abstract: This paper proposes a novel integrated controller with three-layer hierarchical structure to coordinate the interactions among active suspension system (ASS), active front steering (AFS) and direct yaw moment control (DYC). First of all, a 14-degree-of-freedom nonlinear vehicle dynamic model is constructed. Then, an upper layer is designed to calculate the total corrected moment for ASS and intermediate layer based on linear moment distribution. By considering the working regions of the AFS and DYC, the intermediate layer is functionalised to determine the trigger signal for the lower layer with corresponding weights. The lower layer is utilised to separately trace the desired value of each local controller and achieve the local control objectives of each subsystem. Simulation results show that the proposed three-layer hierarchical structure is effective in handling the working region of the AFS and DYC, while the quasi-experimental result shows that the proposed integrated controller is able to improve the lateral and vertical dynamics of the vehicle effectively as compared with a conventional electronic stability controller.

142 citations

Journal ArticleDOI
TL;DR: Simulation and hardware-in-loop implementation results show that the proposed shared control paradigm based robust path-tracking controller can robustly provide better lateral stability when time-varying lateral disturbances are bounded.
Abstract: Stability as well as robustness is the major concerns in the design of a trajectory tracking controller for an autonomous vehicle. In this paper, a novel lateral stability controller design for vehicle path tracking is developed. First, using dynamic game theory as a general framework, vehicle lateral stability can be viewed as a dynamic difference game so that its two players, namely, the active front steering (AFS) system and active rear steering (ARS) system can work together to provide more stability for vehicle path tracking control. The interactive steering control strategies between AFS and ARS are obtained by noncooperative closed-loop feedback Stackelberg game theory to ensure optimal performance for vehicle path tracking. Then, based on the proposed path-following shared control paradigm, by applying the method of zero-sum game theory, a finite-time robust regulator is developed to make the interaction model more robust to uncertain lateral disturbances. Finally, double-lane change and serpentine driving condition with and without uncertain time-varying lateral disturbance are used to evaluate the proposed control algorithm. Simulation and hardware-in-loop implementation results show that the proposed shared control paradigm based robust path-tracking controller can robustly provide better lateral stability when time-varying lateral disturbances are bounded.

69 citations

Journal ArticleDOI
TL;DR: In this paper, active front steering (AFS) can enhance the vehicle yaw stability, but the control of vehicle YAW rate is very challenging due to the unmodelled nonlinearity and uncertainties in v...
Abstract: Active front steering (AFS) can enhance the vehicle yaw stability. However, the control of vehicle yaw rate is very challenging due to (1) the unmodelled nonlinearity and uncertainties in v...

31 citations

Journal ArticleDOI
TL;DR: In this article, a distributed control architecture for integrated control of active front steering (AFS) system and direct yaw moment (DYC) system is proposed, where the cooperative control strategies of two agents are obtained through Paretooptimality theory to ensure optimal control performance of AFS and DYC.
Abstract: Reconstitution of control architecture creates a great challenge for distributed drive electric vehicles (DDEV), due to the emergence of a new distributed driving strategy. To this end, a novel distributed control architecture is proposed in this paper for integrated control of active front steering (AFS) system and direct yaw moment (DYC) system. First, a multi-agent system (MAS) is employed to construct a general framework, where AFS and DYC act as agents that work together to improve vehicle lateral stability and simultaneously reduce workloads of drivers during path tracking. The cooperative control strategies of two agents are obtained through Pareto-optimality theory to ensure optimal control performance of AFS and DYC. Then, on the basis of dynamic interaction between agents, terminal constraints, including terminal cost function and terminal input with local static feedback, are designed to guarantee the asymptotic stability of the close-loop system. Finally, virtual simulations are conducted to evaluate the proposed controller. The results indicate that the proposed control architecture can effectively preserve vehicle stability and reduce workloads of drivers, especially for the inexperienced driver. Furthermore, the hardware-in-loop (HIL) test results also demonstrate the feasibility of the proposed controller.

30 citations