Real-Time Look-Ahead Distance Optimization for Smooth and Robust Steering Control of Autonomous Vehicles

Abstract

This paper presents an optimization problem for the look-ahead distance used in lateral automated vehicle control. A relation is formulated to describe the sensitivity of the control input steering speedδ with respect to the variation of the look-ahead distance L. The nonlinear relation is written as an LPV model using the grid-based approach. The aim is to design a controller which minimizes the steering speedδ by optimizing an additional look-ahead distance L d that is added to the nominal look-ahead distance. Such action generates a smooth/stable vehicle motion when subjected to high oscillations due to noises, large lateral errors, etc. The proposed solution is based on the Linear Parameter Varying (LPV) control approach, where an output-feedback dynamic controller is designed based on Linear Matrix Inequalities (LMIs). The control synthesis is carried out using the grid-based approach combined with the H∞ control problem. Simulation results show the tracking performance and the smoothness of the steering input, when the vehicle is subjected to successive large lateral errors, which provides a comfortable riding.

Design and Comparison of Two Advanced Driving Assistance Systems for the Lane Keeping in Intelligent Vehicles, Based on $L P V / \mathscr{H}_{\infty}$ and Super-Twisting Sliding Mode (STSM) Control Techniques

“…This filter forces the steering system to act at this frequency in order to avoid driver annoyance. This filter design is inspired from [12]. The novelty here is the dependency of W δ (ρ) on ρ, which allows to promote or penalize the steering depending on all possible situations.…”

“…Referring to this analysis, the scheduled gain ρ feeds the LPV /H ∞ controller with the sufficient information about the weights to be pushed or attenuated. The relation between ρ and λ is presented by a "sigmoid" function (12) (see Fig. 4).…”

Adaptive Look-Ahead Distance Based on an Intelligent Fuzzy Decision for an Autonomous Vehicle

“…[8] proposed an improved PP with an adaptive adjustment of the look-ahead distance based on the steering angle and the deflection angle. [9] proposed a non-linear relation between the look-ahead distance and the steering angle rate and the velocity. The aim was to design a controller that minimizes the steering angle rate by determining a proper look-ahead distance.…”