Collision avoidance

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

Computationally efficient intersection collision avoidance system

Abstract: The present invention discloses a back-propagating intersection collision avoidance (ICA) system for preventing two or more vehicles from colliding at an intersection. The ICA system can calculate predicted positions of the two or more vehicles in the near future, and both the current and future positions can be broadcast to surrounding vehicles using vehicle-to-vehicle communication. For each vehicle, a set of states, for example position, speed, acceleration, and the like, where a collision is imminent can be identified using state information for a local vehicle, a remote vehicle, and a known collision zone for the intersection. If the current states of the vehicles are determined to be in danger of entering the collision zone, the ICA system can control the vehicles to perform evasive driving maneuvers and/or alert the drivers.

Driver brake vs. steer response to sudden forward collision scenario in manual and automated driving modes

Abstract: In autonomous vehicle operation, situations may arise when the driver is required to re-engage in manual control of the vehicle. Whether the control handoff from vehicle to human is done in a structured or unstructured manner, the process may be affected by the driver’s state, i.e. distracted or not. The study reported here was designed to measure a non-distracted driver’s response to a sudden forward collision (FC) event, in which the driver would assume manual control of the autonomous vehicle. Three driving scenarios were investigated: autonomous vehicle driven with full collision avoidance support, autonomous vehicle driven without collision avoidance support, and vehicle driven in manual mode. Forty-eight volunteers participated in a simulator study conducted in VIRTTEX. It was found that, at handoff, (1) drivers in manual mode tended to use evasive steering, rather than braking, compared to drivers in both the autonomous modes, (2) between subjects variations in speed were higher for the automation with collision support condition than for the other two scenarios, (3) for both autonomous driving scenarios, drivers reaction times were longer than for manual driving. In some cases the driver response was so late and the distance remaining so reduced that crash avoidance might be unfeasible. At a minimum, results of this study suggest that drivers may benefit from appropriate driver assistance technologies when a crash imminent situation is suddenly encountered.

Studying Gaze Behaviour during Collision Avoidance with a Virtual Walker: Influence of the Virtual Reality Setup

Abstract: Simulating realistic interactions between virtual characters has been of interest to research communities for years, and is particularly important to automatically populate virtual environments. This problem requires to accurately understand and model how humans interact, which can be difficult to assess. In this context, Virtual Reality (VR) is a powerful tool to study human behaviour, especially as it allows assessing conditions which are both ecological and controlled. While VR was shown to allow realistic collision avoidance adaptations, in the frame of the ecological theory of perception and action, interactions between walkers can not solely be characterized through motion adaptations but also through the perception processes involved in such interactions. The objective of this paper is therefore to evaluate how different VR setups influence gaze behaviour during collision avoidance tasks between walkers. To this end, we designed an experiment involving a collision avoidance task between a participant and another walker (real confederate or virtual character). During this task, we compared both the partici-pant‘s locomotion and gaze behaviour in a real environment and the same situation in different VR setups (including a CAVE, a screen and a Head-Mounted Display). Our results show that even if some quantitative differences exist, gaze behaviour is qualitatively similar between VR and real conditions. Especially, gaze behaviour in VR setups including a HMD is more in line with the real situation than the other setups. Furthermore, the outcome on motion adaptations confirms previous work, where collision avoidance behaviour is qualitatively similar in VR and real conditions. In conclusion, our results show that VR has potential for qualitative analysis of locomotion and gaze behaviour during collision avoidance. This opens perspectives in the design of new experiments to better understand human behaviour, in order to design more realistic virtual humans.

Collision monitoring within satellite clusters

Abstract: An autonomous online collision avoidance methodology for satellite clusters is developed and simulated. Contours of probability, defined using state uncertainty ellipsoids, are used to monitor and predict potential collisions over time. The methodology integrates three approaches in order to reduce online computation for autonomous operations while still producing accurate predictions: 1) monitoring distances between bounded probability ellipsoids, which are used to evaluate when and how fast a collision may occur, 2) monitoring ellipsoids as they intersect, then calculating an outer bound of collision probability, and 3) numerical evaluation of collision probability using a three-dimensional (3-D) convolution integral to evaluate conservatism and insure accuracy. The approach assumes the initial state error (relative position and velocity), sensor error, and disturbance function are bounded by ellipsoids to a known level of probability. The methodology can be applied in the presence of different control schemes and system faults. If a collision is imminent, a control reconfiguration can then occur in order to move the healthy satellites to parking orbits. Simulation results show the proposed methodology to not be overly conservative. In addition, results show that satellite clusters with a close proximity will require a backup system that is accurate and gives measurement updates at least every few minutes.

3-D Reciprocal Collision Avoidance on Physical Quadrotor Helicopters with On-Board Sensing for Relative Positioning.

Abstract: In this paper, we present an implementation of 3-D reciprocal collision avoidance on real quadrotor helicopters where each quadrotor senses the relative position and velocity of other quadrotors using an on-board camera. We show that using our approach, quadrotors are able to successfully avoid pairwise collisions in GPS and motion-capture denied environments, without communication between the quadrotors, and even when human operators deliberately attempt to induce collisions. To our knowledge, this is the first time that reciprocal collision avoidance has been successfully implemented on real robots where each agent independently observes the others using on-board sensors. We theoretically analyze the response of the collision-avoidance algorithm to the violated assumptions by the use of real robots. We quantitatively analyze our experimental results. A particularly striking observation is that at times the quadrotors exhibit "reciprocal dance" behavior, which is also observed when humans move past each other in constrained environments. This seems to be the result of sensing uncertainty, which causes both robots involved to have a different belief about the relative positions and velocities and, as a result, choose the same side on which to pass.