Integrated longitudinal and lateral guidance of vehicles in critical high speed manoeuvres

Abstract

One of the most important and conventional manoeuvres, that is not easy to even skilled drivers, is the high-speed critical lane change on the highways. The main contribution of this study is the development of an integrated longitudinal and lateral guidance algorithm for these manoeuvres. This algorithm consists of two parts: the trajectory planning and the integrated control. In the first part, taking into account the position of the target vehicle for different accelerations, several trajectories are produced. Next, considering the dynamic capabilities of the vehicle, the most appropriate trajectory is selected. Since the proposed trajectory planning approach works algebraically, its computational cost is negligible, which is very valuable for practical implementations. In the second step, using a robust-integrated longitudinal–lateral controller, the control inputs are calculated and transmitted to the brakes, throttle and steering actuators. It should be noted that the trajectory planning and the integrated controller are based on the seven degrees of freedom model of the vehicle, and the nonlinear dynamics of the tyre and the dynamics of the brakes/throttle actuators are also taken into account. To assess the efficiency of the integrated longitudinal–lateral guidance algorithm, the full vehicle model is used in the CarSim–Simulink software. In order to have conditions closer to real applications, it is assumed that the yaw rate and the longitudinal and lateral accelerations of the vehicle are noisy, and the longitudinal and lateral velocities are predicted using the same signals. Obtained results for the critical collision avoidance manoeuvres confirm the effectiveness of the proposed planned trajectory and the good performance of the combined control method. In addition, the results indicate that the integrated control is robust against the variation of friction coefficient and unmodelled dynamics while maintaining the vehicle stability.

Longitudinal and lateral control of autonomous vehicles in multi‐vehicle driving environments

“…Note that any trajectory should be confined to the vehicle dynamics limits [28, 30]. Thus, the stable handling envelope is first derived from the vehicle 2‐DOF dynamic model to extract the stable trajectories from the whole trajectory cluster.…”

“…In [29], a linear feedforward and feedback controller with string stability was designed to follow the preceding vehicle, while MPC was applied to regulate the steering angle of the front wheel for lateral tracking. In addition, an integrated controller design [30] was carried out based on a seven‐degree‐of‐freedom vehicle model and the non‐linear dynamics of the tire. The stability of the closed‐loop system was proven via control Lyapunov functions.…”

Vehicle speed preview control with road curvature information for safety and comfort promotion

“…2. Another kind of model is dynamics model considering vehicle lateral dynamics and tyre dynamics, 22–25 which makes the model complex. As the control inputs to the model are the outputs of vehicle mechanical system, the benefit is that the structure of control system is simple.…”

A novel adaptive lane change method in transient dynamic traffic conditions for highly automated vehicles

“…Some researchers assumed the ego vehicle with constant speed during lane change manoeuvre 11,12 or attempted to simplify manoeuvre by considering a linear dynamic model 13–16 or kinematic model 17,18 to control the ego vehicle. Avoiding the effect of nearby vehicles during lane change manoeuvre, 19,20 disregarding the speed changes of surrounding vehicles during manoeuvre, 21–24 inability to modify the trajectory during the lane change manoeuvre, 25–27 and even having no alternate trajectory in a situation that there is no safe point in the target lane 28,29 are the most important limitations of previous research.…”