Automatic lateral emergency collision avoidance for a passenger car

Abstract

Longitudinal collision avoidance controllers are of limited benefit for preventing head-on collisions between road vehicles travelling at high speed or for preventing rear end collisions when there is insufficient separation between the vehicles. In these circumstances, aggressive lateral vehicle manoeuvres are more appropriate. This paper develops a controller architecture to perform an emergency lateral collision avoidance manoeuvre. Simulation results indicate significant improvements in collision avoidance at vehicle speeds up to 100 [km/hr] using integrated automatic steering and braking.

Trajectory generation for road vehicle obstacle avoidance using convex optimization

“…The method was evaluated by simulation using a non-linear two-track model of a passenger vehicle's longitudinal and lateral dynamics, as described in reference [2], together with a controller similar to those described by Bevan and co-workers [2,27], acting on the brakes and front wheel steering. The model is of a luxury passenger car equipped with front-wheel steer-by-wire and brakeby-wire on each wheel, and represents longitudinal and lateral acceleration and the pitch, roll, and yaw dynamics of an unsprung body.…”

“…It has been found previously that developing a good reference trajectory, i.e. one that the vehicle is capable of tracking, reduces the difficulty of designing vehicle controllers [2].…”

“…A non-optimal method of calculating a feasible trajectory to perform the specified manoeuvre is given by Bevan et al [2]. The technique makes use of physical principles to identify a good trajectory by assuming a friction circle, calculating a corresponding minimum radius of turn for the vehicle, then building a trajectory from the sharpest possible turns connected by straight lines, thus constructing a geodesic path as espoused by Dubins [23].…”

“…Previous work [2] developed an automatic lateral collision avoidance system with a particular hierarchical control architecture consisting of reference trajectory generator, feedforward controller, and feedback controller. The most critical part of this control architecture is the reference trajectory generator, which must generate a path that is sufficiently aggressive to avoid obstructions yet can be tracked feasibly by the feedforward/feedback controller using physically realizable actuation signals under varying vehicle operating conditions.…”

“…In reference [2], an analytical trajectory generation method is based upon physical and geometrical considerations. However, the method assumes a constant vehicle speed and does not therefore take advantage of speed reductions that could allow the vehicle to turn more sharply during the manoeuvre.…”