# Design of A Two-point Steering Path Planner Using Geometric Control

## TL;DR

This paper presents a geometric control-based path planner for autonomous vehicle lane-keeping and lane-changing, emphasizing safety, optimality, and computational efficiency, with a novel two-point steering approach that improves maneuvering and passenger comfort.

## Contribution

It introduces a new path planning method satisfying multiple design objectives and a two-point steering strategy with proven advantages in steering radius reduction.

## Key findings

- The proposed path planner generalizes across vehicle models.
- The two-point steering reduces steering radius below the reference line.
- The method enhances vehicle speed and passenger comfort on winding roads.

## Abstract

For lateral vehicle dynamics, planning trajectories for lane-keeping and lane-change can be generalized as a path planning task to stabilize a vehicle onto a target lane, which is a fundamental element in nowadays autonomous driving systems. On the other hand, two-point steering for lane-change and lane-keeping has been investigated by researchers from psychology as a sensorimotor mechanism of human drivers. In the first part of this paper, using knowledge of geometric control, we will first design a path planner which satisfies five design objectives: generalization for different vehicle models, convergence to the target lane, optimality, safety in lane-change maneuver and low computational complexity. Later, based on this path planner, a two-point steering path planner will be proposed and it will be proved rigorously that this two-point steering path planner possesses the advantage--steering radius of the planned trajectory is smaller than the intrinsic radius of reference line of the target lane. This advantage is also described as "corner-cutting" in driving. The smaller driving radius of the trajectory will result in higher vehicle speed along the winding roads and more comfortness for the passengers.