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As demands increase for goods transportation services, long articulated vehicles are introduced as a viable alternative to conventional heavy-duty vehicles. Nowadays, steering control systems are commonly used for enhancing the stability and handling of articulated vehicles. As situations become more difficult for the movement of a vehicle, the ability of the steering actuators decreases and it will not be possible to use this controller alone in critical maneuvers. Another effective way to adjust the directional dynamics of a long articulated vehicle is the simultaneous application of the braking and steering systems. In a situation where the vehicle is close to the ultimate steering limit, it is desirable to reduce the speed, and the steering system can be strengthened through the intervention of the braking system. In this article, a 23 degree of freedom dynamic model of the long articulated vehicle has been developed in MATLAB software. After determining the reference control variables, we will design a sliding mode controller to steer the tractor's front axle and the semi-trailer's rear axles. After defining and setting the weight coefficients using a performance indicator, we will design an integrated controller in a way that if maneuvers become more difficult to perform and the efficiency of the steering actuators decreases, the braking forces exerted on the tractor's rear axle and the semi-trailer's rear axles will take a share in regulating the vehicle's movement. The main achievement of this article is the introduction of a new method to integrate braking and steering control systems in long articulated vehicles. The paper aims to prove that only if manoeuvres become more difficult to perform and the performance of steering actuators decreases, then braking forces can take part in regulating the vehicle's movement. [ABSTRACT FROM AUTHOR]

Today, use of articulated long vehicles is surging. The advantages of using large articulated vehicles are that fewer drivers are used and fuel consumption decreases significantly. The major problem of these vehicles is inappropriate lateral performance at high speed. The articulated long vehicle discussed in this article consists of tractor and two semi-trailer units that widely used to carry goods. The main purpose of this article is to design an adaptive sliding mode controller that is resistant to changing the load of trailers and measuring the noise of the sensors. Control variables are considered as yaw rate and lateral velocity of tractor and also first and second articulation angles. These four variables are regulated by steering the axles of the articulated vehicle. In this article after developing and verifying the dynamic model, a new adaptive sliding mode controller is designed on the basis of a nonlinear model. This new adaptive sliding mode controller steers the axles of the tractor and trailers through estimation of mass and moment of inertia of the trailers to maintain the stability of the vehicle. An articulated vehicle has been exposed to a lane change maneuver based on the trailer load in three different modes (low, medium and high load) and on a dry and wet road. Simulation results demonstrate the efficiency of this controller to maintain the stability of this articulated vehicle in a low-speed steep steer and high-speed lane change maneuvers. Finally, the robustness of this controller has been shown in the presence of measurement noise of the sensors. In fact, the main innovation of this article is in the designing of an adaptive sliding mode controller, which by changing the load of the trailers, in high-speed and low-speed maneuvers and in dry and wet roads, has the best performance compared to conventional sliding mode and linear controllers. [ABSTRACT FROM AUTHOR]