Original Article A new automated motion planning system of heavy accelerating articulated vehicle in a real road traffic scenario Saeed Shojaei 1 , Ali R Hanzaki 1 , Shahram Azadi 2 and Mohammad A Saeedi 1 Abstract 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 ana- lyses 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 longi- tudinal 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 trajec- tory 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. Keywords Motion planning, trajectory planning, tracking control, collision-free manoeuvres, accelerating articulated vehicle Date received: 14 June 2019; accepted: 1 October 2019 Introduction Each day almost 3700 people die globally in road crashes. Also, road accidents cause tens of millions of disabilities and serious injuries annually. They are the reason of critical social impacts in all countries worldwide. Furthermore, road accidents are known as the eighth cause of mortality for whole ages, and the most important cause of death for those aged from 5 to 29 years. Although serious accidents leading to deaths in the United States declined by about 2% in 2017 in comparison with 2016, and mortality due to tractor-semitrailer accident in 2017 was increased to nearly 5.8% when compared to 2016. 1 Consequently, the technologies that are able to reduce road accidents should get more attention especially for tractor- semitrailers. In the last three decades, academic and industrial studies have been increased to develop the technolo- gies of driverless vehicles. Using Electronic Control Systems (ECS) from the active safety systems such as electronic stability program (ESP) to Advanced Driver Assistance Systems (ADAS) like Traffic Jam Assist (TJA), has led to the reduction of road fatal accidents in the European Union from 2001 to 2015 by up to 48%. 2 The purpose of automatic driving is to improve safety and efficiency, to reduce energy con- sumption, and to optimise the traffic flow. These tech- nologies are able to reduce the risk of collision. 3 The academic and industrial studies show that road Proc IMechE Part K: J Multi-body Dynamics 0(0) 1–24 ! IMechE 2019 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1464419319886387 journals.sagepub.com/home/pik 1 Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran 2 Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran Corresponding author: Saeed Shojaei, Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran 16788, Islamic Republic of Iran. Email: saeed_shojaei8@yahoo.com