Motion planning in dynamic environments: obstacles moving along arbitrary trajectories

Abstract

This paper generalizes the concept of velocity obstacles [3] to obstacles moving along arbitrary trajectories. We introduce the non-linear velocity obstacle, which takes into account the shape, velocity and path curvature of the moving obstacle. The non-linear vobstacle allows selecting a, single avoidance maneuver (if one exists) that avoids any number of obstacles moving on any known trajectories. For unknown trajectories, the non-linear v-obstacles can be used to generate local avoidance maneuvers based on the current velocity and path curvature of the moving obstacle. This elevates the planning strategy to a second order method, compared to the first order avoidance using the linear v-obstacle, and zero order avoidance using only position information. Analytic expressions for the non-linear vobstacle are derived for general trajectories in the plane. The non-linear v-obstacles are demonstrated in a complex traffic example.

Real-Time Robot Path Planning via a Distance-Propagating Dynamic System with Obstacle Clearance

“…Such behavior requires an estimation of the moving obstacle's velocity, and not just its position. Work along these lines has been done by Shiller and others [21], [22]. Fraichard and others [23], [24] have used obstacle velocity information to define "inevitable collision states" which must be avoided by the robot.…”

Collision Avoidance from Multiple Passive Agents with Partially Predictable Behavior

“…• First, it generalizes the concept of Nonlinear velocity obstacle (NLVO) [27] to develop a new approach to identify the set of control inputs to robot that will lead the robot towards collision, named control obstacle. It seeks to address the issue of navigating a robot with kinodynamic constraints while considering that a passive agent is moving along an arbitrary path, probably non-linear.…”

“…The early approach was developed for simple agent dynamics to avoid collision with a passive agent which is moving along a straight path with constant velocity. In [27], authors proposed NLVO algorithm, which expands the concept of VO to allow an agent with linear equation of motion to avoid collision with a passive agent with known, possibly nonlinear trajectories. The generalized velocity obstacle (GVO) algorithm proposed in [26] does principally the opposite of NLVO.…”

“…To illustrate the concept of safe control space, take an example of a simple robot R A that was considered in [27]. The position of the center of a disc-shaped robot R A , at time t, for a given control input u, is given as…”

“…This section will review the concept of nonlinear velocity obstacle proposed in [27] and discuss its application for a robot with kinodynamic constraints.…”