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In this paper, a new decision-making algorithm for double lane change maneuver of an articulated vehicle in real dynamic circumstances is studied. A novel method for determining the decision conditions is used based on the articulated vehicle kinematics and dynamics. Through this method, several points of the articulated vehicle are considered in various situations when conducting double lane change maneuver, and the critical points are determined. A new realistic dynamic method is used based on a 16-degrees of freedom dynamic model of the articulated vehicle. The sliding mode control method is utilized to increase the method efficiency. Therefore, the least safe time to perform the double lane change maneuver is extracted based on the sliding mode control method as tracking control. A new Articulated Vehicle Least safe time formulation is determined for dynamic circumstances. Based on the results of simulated test, the acceptable time range is also established for conducting the lane change maneuver. The lane change maneuver is generalized to the double lane change maneuver. Decision-making algorithm is introduced based on real traffic situations. The dynamic approach and the decision-making algorithm are verified. Results show the validity of the reflected method meaning that the decision-making algorithm is acceptable.

In this paper to improve manoeuvrability and jackknifing prevention, as well as increasing rollover stability of an articulated vehicle carrying liquid, a new control system coupled with an active roll control system and an active steering control system is presented. First, a 16-degrees-of-freedom nonlinear dynamic model of an articulated vehicle is developed. Next, the dynamic interaction of the liquid cargo with the vehicle is investigated by integrating a quasi-static liquid sloshing model with a tractor semi-trailer model. Initially, to improve the roll stability of the vehicle, an active roll control system is presented. The active anti-roll bar is employed as an actuator to generate the roll moment. Furthermore, the manoeuvrability increment and jackknifing prevention are targeted using the active steering control system. The main purpose of using the active steering controller is to track the desired values of tractor yaw rate, articulation angle and tractor lateral velocity in different roads, various filled volumes and different speeds. The active steering control system is designed based on a three-degrees-of-freedom dynamic model of the articulated vehicle carrying liquid and on the basis of sliding mode control. Simulation results confirmed robust performance of the control system for different filled volumes, especially during the critical manoeuvre. Further studies show that the tracking of the desired articulation angle has not only eliminated the off-tracking path, but also has made the semi-trailer rear end follow the fifth wheel path.

The main purpose of this study is to develop a novel motion planning for an articulated vehicle (AV) in real traffic situations. This motion planning generates collision-free and feasible trajectories based on kinematic and dynamic analyses of the AV concerning its surrounding vehicles. For this purpose, the collision-free trajectories are simulated in the presence of other vehicles, when the AV is conducting a lane change manoeuvre. A new method is utilised to derive the feasible trajectories by taking into account 3-D surface of the slip angle, roll angle, and lateral acceleration of the AV. This paper presents a new approach to generate the trajectory of an accelerating AV considering the surrounding vehicles in manoeuvre, which are either accelerating or decelerating. The optimal trajectory is then obtained based on the longitudinal acceleration of the AV and the time duration of the lane change manoeuvre, aimed at trajectory tracking control. Therefore, a 3-DOF dynamic model of the AV, including the yaw-rate, lateral velocity of the tractor and articulation angle, is developed. The tyres dynamic is simulated using non-linear Dug-off model. Furthermore, an innovative trajectory tracking control system is proposed concerning a sliding mode control. The developed dynamic model of the AV is verified by the Truck-Sim model. Results show that the collision-free and feasible trajectories can be generated based on the newly presented method of trajectory planning. The outcomes of the trajectory tracking control as the final part of the motion planning system indicate that the heavy articulated vehicle can be guided according to the new automated motion planning.

This paper presents a new effective method in order to achieve an appropriate performance for a four-wheeled vehicle during different conditions. The main goal of the study is focused on the handling improvement and lateral stability increment of the vehicle using a robust combined control system. First, in order to increase the vehicle's manoeuvrability, an active steering control system is proposed based on the sliding mode control method and using the simplified dynamic model. The tracking of the desired values of the yaw rate and lateral velocity of the vehicle is the main purpose for using the controller. Also, in order for verifying the performance of the sliding mode controller, the linearization feedback control method is used to design the active steering control system. Moreover, to improve the directional stability of the vehicle, a new active roll control system is proposed. In this control system, the roll angle is considered as the state variable as well as the active anti-roll-bar is utilized as an actuator to generate the roll moment. Then, a 14-degrees-of-freedom nonlinear dynamic model of the vehicle validated using CarSim software is utilized. Afterward, the performance of the designed combined control system is investigated at various velocities. The simulation results confirm that the combined control system has an important effect on vehicle's manoeuvrability improvement and its lateral stability increment, especially during severe transient manoeuvre.

In this paper, in order to improve the roll stability of an articulated vehicle carrying a liquid, an active roll control system is utilized by employing two different control methods. First, a 16-degree-of-freedom non-linear dynamic model of an articulated vehicle is developed. Next, the dynamic interaction of the liquid cargo with the vehicle is investigated by integrating a quasi-dynamic liquid sloshing model with a tractor-semitrailer model. Initially, to improve the lateral dynamic stability of the vehicle, an active roll control system is developed using classical integral sliding-mode control. The active anti-roll bar is employed as an actuator to generate the roll moment. Next, in order to verify the classical sliding-mode control performance and to eliminate its chattering, the backstepping method and the sliding-mode control method are combined. Subsequently, backstepping sliding-mode control as a new robust control is implemented. Moreover, in order to prevent both yaw instability and jackknifing, an active steering control system is designed on the basis of a simplified three-degree-of-freedom dynamic model of an articulated vehicle carrying a liquid. In the introduced system, the yaw rate of the tractor, the lateral velocity of the tractor and the articulation angle are considered as the three state variables which are targeted in order to track their desired values. The simulation results show that the combined proposed roll control system is more successful in achieving target control and reducing the lateral load transfer ratio than is classical sliding-mode control. A more detailed investigation confirms that the designed active steering system improves both the lateral stability of the vehicle and its handling, in particular during a severe lane-change manoeuvre in which considerable instability occurs.

In the current research, a series of different combinations of plasma SDBD actuators mounted on a simplified road vehicle have been experimentally studied to find the optimum position of the actuators for controlling the flow separation and reducing the vehicle form drag. Separation point of the flow over the rear ramp, large trailing vortices of the standard model, and laminar separation bubble (LSB) of the rear ramp leading edge are among the most significant factors to be controlled. The experiments were conducted at Reynolds numbers ranging from 0.55 × 106 to 1.11 × 106 in a subsonic wind tunnel while the pressure distribution over the model and its streamwise force balance were accurately measured. Significant drag reduction due to the use of DBD actuators was observed. As such, for the range of tested Reynolds numbers, a maximum of 25.1% of drag reduction in the vehicle drag coefficient could be achieved. The optimum combinations of activation voltages (6, 9, and 12 kV) and wave frequencies (6, 10, and 14 kHz) for plasma actuators were also found. Furthermore, it was observed that SDBD actuators mounted on the rear ramp of the model had a deeper impact on the vehicle drag coefficient compared to the other actuators.