Search results for "Collision avoidance"
showing 4 items of 24 documents
DTMC modeling for performance evaluation of DW-MAC in wireless sensor networks
2016
Synchronized duty cycling (DC) aligns sensor nodes to wake up at the same time in order to reduce idle listening for medium access control (MAC) in wireless sensor networks (WSNs). Demand wakeup MAC (DW-MAC) is a popular synchronous DC MAC protocol which allows nodes to compete and transmit multiple packets in one operational cycle. This multiple packet transmission (MPT) feature makes DW-MAC more energy efficient when comparing with other existing single time competition based protocols such as sensor MAC (S-MAC). In the literature, no analytical model exists to evaluate the performance of DW-MAC. In this paper, we develop two associated discrete time Markov chain (DTMC) models and incorpo…
Collision Avoidance Trajectory for an Ekranoplan.
2009
The risk of collision is one of the crucial aspects for the applications of Ekranoplans in civil transportation. In fact, the extremely low flight altitude of these aircraft increases dramatically the chances of interference between their flight path and the multitude of obstacles populating the surrounding area. In this work we consider the optimal collision avoidance problem between a cruising Ekranoplan and a steady obstacle located on its flight path. First we solve the optimal control problem imposing that the collision avoidance maneuver lies on the longitudinal plane identified by the initial cruising conditions. In the second part of this work we state the three-dimensional version …
Collision Avoidance with Potential Fields Based on Parallel Processing of 3D-Point Cloud Data on the GPU
2014
In this paper we present an experimental study on real-time collision avoidance with potential fields that are based on 3D point cloud data and processed on the Graphics Processing Unit (GPU). The virtual forces from the potential fields serve two purposes. First, they are used for changing the reference trajectory. Second they are projected to and applied on torque control level for generating according nullspace behavior together with a Cartesian impedance main control loop. The GPU algorithm creates a map representation that is quickly accessible. In addition, outliers and the robot structure are efficiently removed from the data, and the resolution of the representation can be easily ad…
Real-time smoothing of car-following data through sensor-fusion techniques
2011
Abstract Observation of vehicles kinematics is an important task for many applications in ITS (Intelligent Transportation Systems). It is at the base of both theoretical analyses and application developments, especially in case of positioning and tracing/tracking of vehicles, car-following analyses and models, navigation and other ATIS (Advanced Traveller Information Systems), ACC (Adaptive Cruise Control) systems, CAS and CWS (Collision Avoidance Systems and Collision Warning Systems) and other ADAS (Advanced Driving Assistance Systems). Modern technologies supply low-cost devices able to collect time series of kinematic and positioning data with medium to very high frequency. Even more da…