Collision avoidance

About: Collision avoidance is a research topic. Over the lifetime, 8014 publications have been published within this topic receiving 111414 citations.

Adaptive stress testing of airborne collision avoidance systems

Abstract: This paper presents a scalable method to efficiently search for the most likely state trajectory leading to an event given only a simulator of a system. Our approach uses a reinforcement learning formulation and solves it using Monte Carlo Tree Search (MCTS). The approach places very few requirements on the underlying system, requiring only that the simulator provide some basic controls, the ability to evaluate certain conditions, and a mechanism to control the stochasticity in the system. Access to the system state is not required, allowing the method to support systems with hidden state. The method is applied to stress test a prototype aircraft collision avoidance system to identify trajectories that are likely to lead to near mid-air collisions. We present results for both single and multi-threat encounters and discuss their relevance. Compared with direct Monte Carlo search, this MCTS method performs significantly better both in finding events and in maximizing their likelihood.

A Stochastic Model for Chain Collisions of Vehicles Equipped With Vehicular Communications

Abstract: Improvement of traffic safety by cooperative vehicular applications is one of the most promising benefits of vehicular ad hoc networks (VANETs) However, to properly develop such applications, the influence of different driving parameters on the event of vehicle collision must be assessed at an early design stage In this paper, we derive a stochastic model for the number of accidents in a platoon of vehicles equipped with a warning collision notification system, which is able to inform all the vehicles about an emergency event In fact, the assumption of communications being used is key to simplify the derivation of a stochastic model The model enables the computation of the average number of collisions that occur in the platoon, the probabilities of the different ways in which the collisions may take place, as well as other statistics of interest Although an exponential distribution has been used for the traffic density, it is also valid for different probability distributions for traffic densities, as well as for other significant parameters of the model Moreover, the actual communication system employed is independent of the model since it is abstracted by a message delay variable, which allows it to be used to evaluate different communication technologies We validate the proposed model with Monte Carlo simulations With this model, one can quickly evaluate numerically the influence of different model parameters (vehicle density, velocities, decelerations, and delays) on the collision process and draw conclusions that shed relevant guidelines for the design of vehicular communication systems, as well as chain collision avoidance applications Illustrative examples of application are provided, although a systematic characterization and evaluation of different scenarios is left as future work

Formal verification of distributed aircraft controllers

Abstract: As airspace becomes ever more crowded, air traffic management must reduce both space and time between aircraft to increase throughput, making on-board collision avoidance systems ever more important. These safety-critical systems must be extremely reliable, and as such, many resources are invested into ensuring that the protocols they implement are accurate. Still, it is challenging to guarantee that such a controller works properly under every circumstance. In tough scenarios where a large number of aircraft must execute a collision avoidance maneuver, a human pilot under stress is not necessarily able to understand the complexity of the distributed system and may not take the right course, especially if actions must be taken quickly. We consider a class of distributed collision avoidance controllers designed to work even in environments with arbitrarily many aircraft or UAVs. We prove that the controllers never allow the aircraft to get too close to one another, even when new planes approach an in-progress avoidance maneuver that the new plane may not be aware of. Because these safety guarantees always hold, the aircraft are protected against unexpected emergent behavior which simulation and testing may miss. This is an important step in formally verified, flyable, and distributed air traffic control.

Decentralized feedback controllers for multi-agent teams in environments with obstacles

Abstract: We propose a method for synthesizing decentralized feedback controllers for a team of multiple heterogeneous agents navigating a known environment with obstacles. The controllers are designed to drive agents with limited team state information to goal sets while avoiding collisions and maintaining specified proximity constraints. The method, its successful application to nonholonomic agents in dynamic simulation, and its limitations are presented in this paper.

A novel approach for assistance with anti-collision decision making based on the International Regulations for Preventing Collisions at Sea

Abstract: Marine intelligent anti-collision regulations have been a means of dealing with a particularly dangerous problem for many years. As the foundation for making anti-collision decisions, the Internati...