Saturated feedback control for an automated parallel parking assist system

Abstract

This paper considers the parallel parking problem of automatic front-wheel steering vehicles. The problem of stabilizing the vehicle at desired position and orientation is seen as an extension of the tracking problem. A saturated control is proposed which achieves quick steering of the system near the desired position of the parking spot with desired orientation and can be successfully used in solving parking problems. In addition, in order to obtain larger area of the starting positions of the vehicle with respect to the parking spot for the first reverse maneuver of the parallel parking, an approach of using saturated control with two different levels of saturation is proposed. The vehicle can be automatically parked by using one or multiple maneuvers, depending on the size of the parking spot. Simulation results are presented to confirm the effectiveness of the proposed control schemes.

Automatic Perpendicular and Diagonal Unparking Using a Multi-Sensor-Based Control Approach

“…where v max is an adaptive saturation value imposing a deceleration profile based on the velocity profile shown in [4] as the vehicle approaches the final pose. Furthermore, to avoid large changes in the control signals at the current iteration n that may cause uncomfortable sensations for the passengers or surrounding witnesses and, to consider to some extent the dynamic limitations of the vehicle, the control signals are saturated as well by some increments with respect to the previous control signals (at iteration n − 1) as shown below:…”

“…Even if the focus of most works in the literature is on the parking task, if a path is found it can be used as well for unparking. Among the different planning techniques it is possible to distinguish between geometric approaches, with either constant turning radius [3], [4] using saturated feedback controllers, or continuous-curvature planning using clothoids [5], [6]; heuristic approaches [7] and machine learning techniques [8].…”

Autonomous parking using a sensor based approach

“…1) Velocity profile: Regarding the velocity profile of the vehicle, it is determined from the following expressions [11] if…”

Laser-Based Control Law for Autonomous Parallel and Perpendicular Parking

“…where v max is an adaptive bound imposing a deceleration profile based on the velocity profile shown in [5] as the vehicle approaches the final pose. Finally, to avoid large changes in the control signals at time instant n that may cause uncomfortable sensations for the passengers or surrounding witnesses and to consider to some extent the dynamic limitations of the vehicle, the control signals are saturated by some increments with respect to the control signal at n − 1 as shown below:…”

“…Among the different planning techniques it is possible to distinguish between geometric approaches, with either constant turning radius [4], [5] using saturated feedback controllers, or continuous-curvature planning using clothoids [6]; heuristic approaches [7] and machine learning techniques [8]. It is worth to note that parking maneuvers with forward motions are seldom considered, with [9] for the parallel parking case and [10] for the perpendicular case being some of the few works on this regard.…”