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Showing papers on "Collision avoidance published in 1988"


Journal ArticleDOI
01 Jan 1988
TL;DR: The obstacle avoidance strategy used for this robot is described, which depends heavily on the performance of the ultrasonic range finders, these sensors and the effect of their limitations on the obstacle avoidance algorithm are discussed in detail.
Abstract: A mobile robot system, capable of performing various tasks for the physically disabled, has been developed. To avoid collision with unexpected obstacles, the mobile robot uses ultrasonic range finders for detection and mapping. The obstacle avoidance strategy used for this robot is described. Since this strategy depends heavily on the performance of the ultrasonic range finders, these sensors and the effect of their limitations on the obstacle avoidance algorithm are discussed in detail. >

451 citations


Book
01 Jun 1988
TL;DR: In this article, the authors describe strategies of cooperation that groups require to solve shared tasks effectively and discuss such strategies in the context of a specific group problem solving application: collision avoidance in air traffic control.
Abstract: Distributed Artificial Intelligence is concerned with problem solving in which groups solve tasks. In this paper we describe strategies of cooperation that groups require to solve shared tasks effectively. We discuss such strategies in the context of a specific group problem solving application: collision avoidance in air traffic control. Experimental findings with four distinct air-traffic control systems, each implementing a different cooperative strategy, are mentioned.

271 citations


Patent
31 Oct 1988
TL;DR: In this paper, a method of static collision avoidance for multiple automatically guided vehicles (AGVs) on bidirectional paths is proposed, which allows multiple AGVs to coexist in the same pathways without collision or excessive queueing.
Abstract: The invention is a method of static collision avoidance for multiple automatically guided vehicles (AGVs) on bidirectional paths. It defines the allowable travel path for an AGV as a series of path segments through or between possible destination points (called nodes) which are defined for the factory floor. AGVs can move to or through any of these nodes and can arrive in a predetermined order, according to "rules" defined by the method. The invention provides better performance than conventional AGV systems by allowing multiple AGVs to coexist in the same pathways without collision or excessive queueing in systems which use free-roving AGVs having programmable bidirectional paths. This new ability maximizes the degrees of freedom of AGV movement while minimizing collisions and "deadlock."

84 citations


Journal ArticleDOI
TL;DR: The paper describes an approach to the solution of the find path problem, including obstacle avoidance in multirobot systems, which is based on the nonlinear approach and employs the hierarchical coordinator for real-time collision avoidance.
Abstract: The paper describes an approach to the solution of the find path problem, including obstacle avoidance in multirobot systems. The design of multirobot systems requires an overall approach where not only parts of the structure, including the hierarchy are considered, but a complete concept, including the dynamics of the robots, has to be developed. In this paper the structure of these systems is based on the nonlinear con trol approach. The method for real-time pathfinding itself uses a systematic design procedure for multirobot systems, which includes the hierarchical coordinator. This hierarchical coordinator is designed for real-time collision avoidance, where the collision avoidance strategy is based on an analyti cally described avoidance trajectory that serves for collision detection as well as avoidance. The efficiency of the new approach for real-time pathfinding is demonstrated by several cases of practical interest, such as collision avoidance between three robots, interaction of three stationary...

82 citations


Journal ArticleDOI
TL;DR: Familiarity, adaptability, and adaptability are key characteristics of a truly democratic society.
Abstract: 本論文ではファジィ推論およびプロダクションルールを適用した移動ロボットの障害物回避方式を提案する.本方式の第1ステップでは, ファジィ推論によりロボットと障害物との間の静的および動的危険度を認識する.第2ステップでは, この危険度を用いてディシジョンテーブルで回避方向を決定する.この方式を用いると動的障害物に対するヒューリスティック回避を実現できる.ここでは, 本方式の有効性を検証したシミュレーション結果について報告する.

41 citations


Journal ArticleDOI
TL;DR: A two-level hierarchy for planning collision-free trajectories in time varying environments is proposed that makes effective use of the complementary aspects of the global trajectory planning approaches and the local obstacle avoidance approaches.
Abstract: We propose a two-level hierarchy for planning collision-free trajectories in time varying environments. Global geometric algorithms for trajectory planning are used in conjunction with a local avoidance strategy. Simulations have been developed for a mobile robot in the plane among stationary and moving obstacles. Essentially, the robot has a global geometric planner that provides a coarse global trajectory (the path and velocity along it), which may be locally modified by the low-level local avoidance module if local sensors detect any obstacles in the vicinity of the robot. This hierarchy makes effective use of the complementary aspects of the global trajectory planning approaches and the local obstacle avoidance approaches.

36 citations


Proceedings ArticleDOI
01 Oct 1988
TL;DR: This paper describes a collision avoidance warning system that uses a laser radar sensor to detect distance and a microcomputer to both assess the risk of a rear-end collision and provide warnings in dangerous situations.
Abstract: This paper describes a collision avoidance warning system. The system uses a laser radar sensor to detect distance and a microcomputer to both assess the risk of a rear-end collision and provide warnings in dangerous situations. The system also has an unnecessary warning suppression feature. A test of the system also showed a low false alarm rate.

16 citations


Proceedings ArticleDOI
24 Apr 1988
TL;DR: The authors focus on collision detection for planning collision-free motion of two robot arms in a common workspace using a sphere model for the wrists and a novel approach to collision detection.
Abstract: The authors focus on collision detection for planning collision-free motion of two robot arms in a common workspace. A collision-free motion is obtained by detecting collisions along the straight-line trajectories of the robots using a sphere model for the wrists and then replanning the paths and/or trajectories of one or both of the robots to avoid collisions. A novel approach to collision detection is presented and a discussion on collision avoidance is given. >

14 citations


Journal ArticleDOI
01 May 1988
TL;DR: For a large class of spherical nonrigid objects, exact solutions of the path existence problem are developed based on decomposition techniques and graph traversal for linear/circular and polynomial paths.
Abstract: The path existence problem and the collision detection problem for time-varying objects in a geometric scene are discussed. For a large class of spherical nonrigid objects, exact solutions of the path existence problem are developed based on decomposition techniques and graph traversal. For the collision detection problem of a single moving circle in the plane, efficient data structures are presented for linear/circular and polynomial paths.

10 citations


Patent
30 Sep 1988
TL;DR: In this paper, a self-contained deceleration system for a motor vehicle is described, which consists of a housing affixed to rear portion of the motor vehicle and an inertia switch is electrically connected within the housing into a circuit with a power source and a red stop light.
Abstract: A self contained deceleration system for a motor vehicle is provided and consists of a housing affixed to rear portion of the motor vehicle. An inertia switch is electrically connected within the housing into a circuit with a power source and a red stop light. When the motor vehicle decelerates the inertia switch will momenterally close allowing the red stop light to illuminate to indicate that the motor vehicle is slowing down.

10 citations


Patent
09 May 1988
TL;DR: In this paper, an aircraft collision potential warning system is proposed, in which each aircraft includes means for transmitting pulse sequences, in pseudo random or random fashion and on a common frequency, which include aircraft identification and altitude information.
Abstract: An aircraft collision potential warning system in which each aircraft includes means for transmitting pulse sequences, in pseudo random or random fashion and on a common frequency, which include aircraft identification and altitude information Each aircraft further includes means to receive and process incoming signals from other aircraft and, on the basis of the altitude information, discard those signals not within a collision potential altitude range If a signal is within a collision potential altitude range, interrogation is effected specifically to the identified signal source and the closing speed between the two aircraft is determined If the rate of change of closing speed is below a set figure, a collision potential exists


28 Jan 1988
TL;DR: In this paper, the authors present a voyage management system which takes navigational data from such navigation aids as are fitted on the vessel, collision avoidance data from the ship's radars, and meteorological data from shore stations via a satellite link.
Abstract: The paper concerns work on the development of a voyage management system which takes navigational data from such navigation aids as are fitted on the vessel, collision avoidance data from the ship's radars, and meteorological data from shore stations via a satellite link. After appropriate filtering, this data is used as input to a multivariable optimal controller which will maintain the vessel on the correct track between ports, with due consideration to safety, efficiency and economy of operation. The navigation and guidance system has been tested afloat, whilst simulation studies have demonstrated that the automatic collision avoidance and weather routeing systems can be incorporated in to the overall voyage management system. The next step is to develop a complete prototype system and undertake extensive trials in coastal and oceanic waters.

Journal ArticleDOI
TL;DR: A hardware solution to this problem is to use collision avoidance switches as mentioned in this paper, which allow the packet collisions and their resolution to create a performance bottleneck in random access LANs, and thus can reduce packet collisions.
Abstract: Packet collisions and their resolution create a performance bottleneck in random access LANs. A hardware solution to this problem is to use collision avoidance switches. These switches allow the im...

Proceedings ArticleDOI
01 Aug 1988
TL;DR: The designs of some tree LANs that use collision avoidance switches, including broadcast star and CAMB tree (Collision Avoidance Multiple Broadcast tree), and a possible implementation of a collision avoidance switch using currently available photonic devices are described.
Abstract: Packet collisions and their resolution create a performance bottleneck in random access LANs. A hardware solution to this problem is to use collision avoidance switches. These switches allow the implementation of random access protocols without the penalty of collisions among packets. We describe the designs of some tree LANs that use collision avoidance switches. The collision avoidance LANs we describe are broadcast star and CAMB tree (Collision Avoidance Multiple Broadcast tree). We next present a possible implementation of a collision avoidance switch using currently available photonic devices. Finally, we show the performance of broadcast star and CAMB tree networks using simulations.

Journal Article
TL;DR: Analyse de la prevention des collisions dans les cellules utilisant plusieurs robots a l'aide des reseaux de Petri.
Abstract: Analyse de la prevention des collisions dans les cellules utilisant plusieurs robots a l'aide des reseaux de Petri

01 Dec 1988
TL;DR: This volume contains the contributions of the participants in the NASA Ames Research Center workshop on the traffic-alert and collision avoidance system (TCAS) implementation for aircraft with cathode ray tube (CRT) or flat panel displays.
Abstract: This volume contains the contributions of the participants in the NASA Ames Research Center workshop on the traffic-alert and collision avoidance system (TCAS) implementation for aircraft with cathode ray tube (CRT) or flat panel displays. To take advantage of the display capability of the advanced-technology aircraft, NASA sponsored this workshop with the intent of bringing together industry personnel, pilots, and researchers so that pertinent issues in the area could be identified. During the 2-day workshop participants addressed a number of issues including: What is the optimum format for TCAS advisories. Where and how should maneuver advisories be presented to the crew. Should the maneuver advisories be presented on the primary flight display. Is it appropriate to have the autopilot perform the avoidance maneuver. Where and how should traffic information be presented to the crew. Should traffic information be combined with weather and navigation information. How much traffic should be shown and what ranges should be used. Contained in the document are the concepts and suggestions produced by the workshop participants.

Journal ArticleDOI
TL;DR: In this paper, the authors describe an AGV built at the Technion, the navigation system, the sensors and the collision avoidance system, and the hierarchical computer control of the AGV.

Patent
17 Aug 1988
TL;DR: In this article, the authors proposed a collision avoidance alarm for producing heavy bridge cranes. And the utility model is composed of a bridge crane body (1), a buffer (5), a wheel (9), and a photoelectric control circuit.
Abstract: The utility model relates to a collision avoidance alarm for producing heavy bridge cranes. The utility model is composed of a bridge crane body (1), a buffer (5), a wheel (9) and a photoelectric control circuit. The utility model is mainly characterized in that a photoelectric head which is fixed on the buffer (5) by a clamping plate (15) and a screw (16) carries out photoelectric conversion; the distance of the photoelectric head is adjusted by an optical source; an alarm device sends out alarm before the inertia stroke of the crane is run; thus, the crane reduces speed, powers off or stops in the chronic stroke, which avoids the collision of the two cranes. The utility model is safe and reliable.



Journal ArticleDOI
TL;DR: This article addressed the problem of collision-free path planning in the context of a gantry type robot by developing a collision avoidance algorithm that permits the manipulation of objects in the robot's environment.
Abstract: A collision avoidance algorithm has been developed to augment the capability of an automatic (off-line) robot path planning (programming) tool. The use of off-line programming tools for robot task programming is becoming increasingly important, but the advantages to be gained by off-line programming may be lost if collision-free path planning capabilities are not included. This article addressed the problem of collision-free path planning in the context of a gantry type robot. The collision avoidance algorithm described here uses the to collision-free path planning. The manipulator and obstacles are modeled as spheres to simplify tests for collision. An important feature of this algorithm is that it permits the manipulation of objects in the robot's environment. When compared against an algorithm from the literature, given a lightly cluttered environment modelled by spheres, the new algorithm finds a collision-free path much faster. This new algorithm has been implemented as part of the CATIA/IBM 7565 interface which forms an automatic off-line programming system for the IBM 7565 robot. It has also been implemented as a supervisory collision filter to allow collision-free control of the robot from the operator's console. In both cases the algorithm has been demonstrated to provide efficient and effective collision avoidance for the IBM 7565 robot.

Book ChapterDOI
01 Jan 1988
TL;DR: The new method CARE (Collision Avoidance in Realtime Environments), presented in this paper, is a new safety methodology that anticipates collision-danger between robots and robots and their environment and it actively avoids a collision by changing the predetermined path of the endangered robots in realtime.
Abstract: With the use of cooperative multi-robot-systems new chances and perspectives are revealed for service, industrial, space- and underwater-applications. A versatile multi-robot-control, which fully exploits the inherent flexibility of a multi-robot-system, guarantees optimized system-throughput and increases system-autonomy significantly [Freund and Rosmann, 1995; Rosmann, 1993]. On the other hand, the flexible use of multi-robot-systems requires new methodologies to ensure safe and collision-free movement of the controlled robots. The “intelligence” of the implemented security measures must keep up with the increase of autonomy of the robotic system. The new method CARE (Collision Avoidance in Realtime Environments), that is presented in this paper, is such a new safety methodology. It anticipates collision-danger between robots and robots and their environment and it actively avoids a collision by changing the predetermined path of the endangered robots in realtime. The planning of evasive actions is performed under consideration of static and dynamic constraints of the robots’ movements and of static and dynamic task-specific constraints. In particular, CARE allows to plan evasive actions without modifying the movement of the TCP only using the redundant kinematics of a robot.

01 Mar 1988
TL;DR: Results show that the recommended avoidance maneuvers increased aircraft miss distance in 37 cases and demonstrate that a 'red and green' RA display is more effective than the current 'red only" RA display.
Abstract: : The objective of this study was to investigate three areas of interaction between pilots and the TCAS II Collision Avoidance System in order to examine the following areas of concern: (1) Did pilots maneuver on traffic advisory (TA) information? (2) Did the pilots' use of the system increase the miss distance between conflicting aircraft? (3) Would an alternate design for the resolution advisory (RA) display be more effective than the current display? The first two questions were answered with data obtained from a NASA-Ames simulation using airline crews and a Boeing 727 flight simulator. Evaluation of these data reveal 14 incidents were pilots successfully maneuvered their aircraft using TA information. Forty scenarios where the TCAS II system directed evasive maneuvers were examined. These results show that the recommended avoidance maneuvers increased aircraft miss distance in 37 cases. Alternate designs for the resolution advisory display were evaluated using military and civilian pilots reacting to a computer display simulation. These results demonstrate that a 'red and green' RA display is more effective than the current 'red only' RA display.


Patent
22 Feb 1988

Journal ArticleDOI
TL;DR: The necessity for such a system has been underlined by mid‐air collisions which have happened over a considerable period of time and growing pressure has meant that the FAA in 1987 issued a Notice of Provisional Rulemaking (NPRM) in which comments about its contents were to have been received before the end of 1987.
Abstract: CONCERN about the development and implementation of collision avoidance systems has occupied companies and authorities for many years in various parts of the world and particularly in the USA where the density of all kinds of air traffic has increased substantially and will continue to do so into the foreseeable future. Although increases of density occur worldwide, the vast amount of private and business flying in North America makes it essential that any workable scheme of collision avoidance must have mandatory general aviation participation. The necessity for such a system has been underlined by mid‐air collisions which have happened over a considerable period of time and growing pressure has meant that the FAA in 1987 issued a Notice of Provisional Rulemaking (NPRM) in which comments about its contents were to have been received before the end of 1987.

Journal ArticleDOI
TL;DR: In this article, the authors deal with the problem of navigation and planning of an automated warehouse equipped with mobile robotic devices in a generalised layout of the warehouse, which is a modular construction type, and develop a path planning algorithm (optimises the path for the shortest distance to the goal) and the collision avoidance strategy for a multiple robot environment.
Abstract: This paper deals with the problem of navigation and planning of an automated warehouse equipped with mobile robotic devices. A generalised layout of the warehouse is considered here, which is a modular construction type. The path planning algorithm (optimises the path for the shortest distance to the goal) and the collision avoidance strategy for a multiple robot environment are developed based on velocity and distance bounds. The landmarks are assumed to supply all pertiment information regarding the module identification and the movement directions, while the sensors are assumed to be capable of maintaining the robot in its correct track and understand the knowledge contained in the landmarks. The path planning and collision avoidance algorithms are programmed and simulated for a multiple robot environment in a construction site warehouse.

01 Jan 1988
TL;DR: The main report of the Community-COST Concertation Committee contains an overview of all work carried out by COST 301, covering maritime traffic patterns, effectiveness of vessel traffic services, and structure of regional vessel services.
Abstract: The main report of the Community-COST Concertation Committee contains an overview of all work carried out by COST 301. Topics covered include: maritime traffic patterns; effectiveness of vessel traffic services; structure of regional vessel services; collision avoidance planning; traffic management; and implementation of vessel traffic services. An appendix to the executive report contains a summary of recommendations.