Showing papers on "Collision avoidance published in 1987"
Journal Article•
130 citations
Patent•
03 Feb 1987TL;DR: In this article, a stellate store and broadcast network with collision avoidance comprising a plurality of terminal devices, a central station for collectively relaying data packets issuing from the terminal devices and broadcasting them to the relevant terminal devices is characterized by further incorporating reception memories disposed one each at the terminal interfaces of the central station.
Abstract: A stellate store and broadcast network with collision avoidance comprising a plurality of terminal devices, a central station for collectively relaying data packets issuing from the terminal devices and broadcasting them to the relevant terminal devices, and bidirectional communication channels interposed one each between the terminal devices and the central station, which stellate store and broadcast network is characterized by further incorporating therein reception memories disposed one each at the terminal interfaces of the central station, control circuits for monitoring the statuses of the reception memories, and means for broadcasting the data read out of the reception memories to all the reception lines.
40 citations
01 Jan 1987
TL;DR: The result shows that the approach discussed here is appropriate to the problem and by increasing production-rules a sophisticated system which can deal with even more complicated encounter situations can be achieved.
Abstract: Automatic collision avoidance is one of the most difficult problems of automatic harbour manoeuvring. An expert system approach was considered to deal with the problem and the development of a prototype system is presented. A computer simulation under various situations including encounters of four ships was carried out to evaluate the performance of the system. The result shows that the approach discussed here is appropriate to the problem and by increasing production-rules a sophisticated system which can deal with even more complicated encounter situations can be achieved.
18 citations
TL;DR: This paper describes a simulation system ROPAS (for RObot PAth Simulation) for testing one approach — called Dynmic Path Planning (DPP) — to sensor-based robot collision avoidance in an environment with unknown obstacles.
Abstract: Computer simulation is a major tool in validation of robot motion planning systems, since, on the one hand, underlying theory of algorithms typically requires questionable assumptions and simplifications, and, on the other hand, experiments with hardware are necessarily limited by available resources and time. This is especially true when the motion planning system in question is based on sensor feedback and the generated trajectory is, therefore, unpredictable. This paper describes a simulation system ROPAS (for RObot PAth Simulation) for testing one approach — called Dynmic Path Planning (DPP) — to sensor-based robot collision avoidance in an environment with unknown obstacles. Using real time graphics animation of the motion planning system, the user can simulate the behavior of an autonomous vehicle or a robot arm manipulator with a fixed base. The overall structure of the system is described, and examples are presented.
14 citations
TL;DR: In this article, the authors describe a scenario where a vehicle is driven by a driver with a driver's license, and the driver is a taxi driver with the license plate of a vehicle.
Abstract: 本稿では, マニピュレータの障害物回避法を提案する.まず, 各障害物と障害物の中間となる面上で0となる様に障害物回避のためのポテンシャル場を定義する.次に, このような面上で, エンドイフェクタの目標軌道の候補となるグラフを求める.我々は, これを安全第一グラフと呼んでいる.このグラフ上での経路は, Aアルゴリズムによって決定する.このようにすると, 障害物を回避するためのポテンシャルによる効果と目標に到達するためのポテンシャルによる効果との相互干渉が非常に小さくなるので, 停留や障害物との衝突による解の探索の失敗が起こりにくくなる.また, この目標軌道という大局的な情報に基づいて, 解の探索の再試行も可能になる.本方法は, 対象とするマニピュレータの機構学的な特徴によらず適用可能であり, 実現可能な動作に対して制約を加えない.本方法の有効性は, シミュレーションにより確認されている.
9 citations
7 citations
7 citations
08 May 1987
TL;DR: In this paper, the authors evaluated the suitability of TCAS equipment for use in helicopters and concluded that the air-to-air surveillance techniques originally developed for large jet airliners will also perform satisfactorily in helicopters.
Abstract: : Subsequent to the development of TCAS(Traffic Alert and Collision Avoidance System) equipment for fixed-wing aircraft, a follow-on effort addressed the suitability of such equipment for use in helicopters This program focused on those differences between helicopters and fixed-wing aircraft that might be expected to affect TCAS performance: the large rotor, the relatively irregular shape of the fuselage, the low speeds and high turn rates typical of helicopter flights, and the over-water and low-altitude conditions typical of helicopter operations A Bell Long Ranger helicopter was acquired and equipped with experimental TCAS equipment with full data recording capability Flight experiments were conducted to assess air-to-air surveillance performance under challenging conditions Other flights involved guest pilots for subjective evaluations of the TCAS performance It was concluded that the air-to-air surveillance techniques that were originally developed for use in large jet airliners will also perform satisfactorily in helicopters The bearing accuracy of traffic advisories, while somewhat degraded because of the effects of the rotor and the shape of the helicopter fuselage, will nevertheless be sufficient to aid the pilot in visual acquisition of traffic It was also concluded that, because of the flight characteristics of helicopters, the pilot display should consist of traffic advisories alone, without resolution advisories Keywords: Collision avoidance; Angle-of-arrival
5 citations
01 Jan 1987
TL;DR: The results of this research represent pilot behavior when introduced to the Traffic-alert and Collision Avoidance System and have more fundamental importance in addressing how much and in what manner information should be presented to flight crews.
Abstract: A flight simulator study of pilots' use of the Traffic-alert and Collision Avoidance System is described. Three levels of information on the location of other air traffic were presented to different groups of airline pilots. The amount of informtion on the location of other traffic had little effect on pilots' performance of the maneuvers commanded by the collision avoidance system. Measured crew responses were similar with no presentation of traffic location, with limited information, and with continuous traffic information. No learning effects were observed, and differences in flight experience did not contribute to the performance difference found.
5 citations
TL;DR: In this paper, the authors propose a framework to improve the quality of the data collected by the data collection system, which is based on the concept of data-driven data collection.
Abstract: 本論文では, マニピュレータの障害物回避動作計画を行うための簡単で汎用的な方法について述べる.より柔軟な生産システムを構築するために, 産業用ロボットを対象とした多くのオフラインプログラミングシステムが開発されているが, 複雑な作業を扱うには十分ではない.さらに強力なプログラミングシステムを実現するためには, マニピュレータの作業環境内の障害物との干渉を自動的に回避する機能が不可欠である.障害物回避の問題に対しては, 多くのアルゴリズムがすでに提案されているが, どのようなマニピュレータに対しても適用できるような簡単で汎用的な方法は, まだ開発されていない.コンフィギュレーション空間に基づく方法が有望と思われるが, コンフィギュレーション空間は多次元空間で, 自由空間のデータ量は膨大になる.しかし, マニピュレータの単一の動作を計画する際には, その大部分のデータは使われない.迷路法に基づく方法では, マニピュレータの構造とは独立に, 経路計画に使われると思われる自由空間を限定できる.このため, マニピュレータのすべてのコンフィギュレーションで干渉計算を行うことが可能になる.自由空間を計算するアルゴリズムは以下のようになる.まず, コンフィギュレーション空間における直線経路において干渉計算を行い, 干渉しないコンフィギュレーションの集合を求める。次に, 隣接するコンフィギュレーションについて干渉するかどうかをチェックする.自由空間はこういった方法で, ちょうど水面上を広がる波面のように計算される.この手順は初期姿勢からの波面と最終姿勢からの波面が衝突するまで続ける.この方法をソリッドモデルベースのロボットプログラミングシステム上にインプリメントし, 多関節型マニピュレータに適用した.
3 citations
10 Jun 1987
TL;DR: This paper describes an approach to collision avoidance for rotorcraft flying at low altitudes based on extracting information from passive image-based sensors that can be used to alert a pilot about obstacles and provide inputs to navigation and guidance systems for further processing.
Abstract: This paper describes an approach to collision avoidance for rotorcraft flying at low altitudes. The method is based on extracting information from passive image-based sensors. These methods can be used to alert a pilot about obstacles and provide inputs to navigation and guidance systems for further processing.
28 Dec 1987
TL;DR: Collision-free motion of two robot arms in a common workspace is investigated by detecting collisions along the preplanned trajectories using a sphere model for the wrist of each robot and modifying the paths and/or trajectories of one or both robots to avoid the collision.
Abstract: Collision-free motion of two robot arms in a common workspace is investigated. A collision-free motion is obtained by detecting collisions along the preplanned trajectories using a sphere model for the wrist of each robot and then modifying the paths and/or trajectories of one or both robots to avoid the collision. Detecting and avoiding collisions are based on the premise that: preplanned trajectories of the robots follow a straight line; collisions are restricted to between the wrists of the two robots (which corresponds to the upper three links of PUMA manipulators); and collisions never occur between the beginning points or end points on the straight line paths. The collision detection algorithm is described and some approaches to collision avoidance are discussed.
01 Jan 1987
TL;DR: In this paper, the authors investigate, delineate, develop and perform tasks related to the development of an automobile collision avoidance radar system, and make recommendations about the likelihood of success of the investigated radar techniques.
Abstract: The purpose of this project was to investigate, delineate, develop and perform tasks related to the development of an automobile collision avoidance radar system. Items within the scope of this efforts were to: 1) review previous authors' work in this field; 2) select a suitable radar approach; 3) develop a system design; 4) perform basic analyses and observations pertinent to radar design performance, and effects; 5) fabricate and collect radar data from a data collection radar; 6) analyze and derive conclusions from the radar data; and, 7) make recommendations about the likelihood of success of the investigated radar techniques.
Patent•
01 Sep 1987
TL;DR: In this paper, an approach information circuit is used to determine a position where an airplane can avoid a collision after a constant time based on the performance of the airplanes whose approach is expected and on the meteorological condition information.
Abstract: PURPOSE:To enable the always precise procedure of collision avoidance to be indicated by calculating a flight performance from the airplane performance of every type of airplanes and meteorological condition in the present flight. CONSTITUTION:An expected position processing circuit 1 is inputted with airplane information (a) from a radar response and outputs the positions and altitudes of all airplanes after a specified time as expected position information (b). An approach information circuit 2 is inputted with the information (b) and calculates the group of airplanes whose approach is expected to occur at distances smaller than a set value as approaching airplane information (c). A flight performance processing circuit 3 is inputted with the information (c) and meteorological condition information (d) and outputs the flight performance which the airplanes whose approach is expected would be able to exhibit under the present meteorological condition as flight performance information (e). In result, the circuit 3 can determine a position wherein an airplane can avoid a collision after a constant time based on the performance of the airplanes whose approach is expected and on the meteorological condition information. An avoidance procedure processing circuit 4 is inputted with the informations (b), (c) and (e) and, taking the expected reaching positions of all the neighboring airplanes into consideration, outputs the procedure of collision avoidance as avoidance procedure information (f).
01 Dec 1987
TL;DR: In this paper, the effects of scattering from major aircraft structures on the TCAS 2 collision avoidance system mounted on a Boeing 737 were investigated and it was found that the major source of scattering for angles of observation above the horizon is the vertical stabilizer and that its effect may be greatly reduced by mounting the array close to the nose of the aircraft.
Abstract: The purpose of this report is to determine the effects of scattering from major aircraft structures on the TCAS 2 collision avoidance system mounted on a Boeing 737. It is found that the major source of scattering for angles of observation above the horizon is the vertical stabilizer and that its effect may be greatly reduced by mounting the TCAS 2 array close to the nose of the aircraft. In addition, by mounting the array close to the nose, the effects of fuselage blockage on the array patterns at elevation angles below the horizon may be greatly reduced in the forward direction.
TL;DR: It becomes possible, by applying this algorithm, to predicate the time at which the collision may happen so that the countermeasure can be made as quickly as possible and the robots can be controlled in real time.
TL;DR: A new approach for extracting the images of moving objects which requires only a sequence of consecutive frames is developed, which allows to detect moving edges and to extract moving objects from their background.
27 Mar 1987
TL;DR: The basic configuration space method has been successfully implemented in a real time collision avoidance algorithm and is integrated with a offline programming utility, and permits the safe utilization of a robot work cell.
Abstract: The basic configuration space method has been successfully implemented in a real time collision avoidance algorithm. The program allows a user to determine a collision free path through obstacles in the path. The program is integrated with a offline programming utility, and permits the safe utilization of a robot work cell. This research is a step towards understanding the safe operation of industrial robots.
01 Jan 1987
TL;DR: This paper deals with the realization of a logical structure for the use of robots in assembly and shows how this structure can be applied to smart grids.
Abstract: This paper deals with the realization of a logical structure for the use of robots in assembly.