Showing papers on "Collision avoidance system published in 1991"

Collision avoidance system

Abstract: A collision avoidance system particularly suited for automotive applications includes an electro-optical rangefinder scanner, retroreflectors on target vehicles, and a processing unit. The rangefinder supplies data on the range and angle of target vehicles to the processor, which monitors each target vehicle's position, speed and acceleration and constantly determines and updates target range, angle, velocity, acceleration and predicted separation distances. A warning signal or evasive manuever instructions are issued if the predicted separation at the time of intercept is below a minimum acceptable value.

Vehicle collision avoidance system

Abstract: The collision avoidance system includes structure mountable at the side mirror position of a vehicle. The system includes a rotatable mirror and an ultrasonic transmitting and receiving unit which is adaptable to scan a predetermined area about the vehicle to detect the presence of an object and to calculate its distance from the vehicle. If the distance and speed are determined to pose a threat, the distance is placed on a display and an alarm is sounded. Two displays are provided, one for the forward end of the vehicle and another for the rear end of the vehicle. The system operates when the vehicle is moving forwardly and rearwardly. Also, when the vehicle is not moving, the presence of a potential intruder is also monitored and the system can actuate an anti-theft alarm of the vehicle. Further, the system can be programmed by a plurality of operators to particular distances, with the system discerning which operator is driving and automatically using that operator's input.

An experimental evaluation of in-vehicle collision avoidance systems

Abstract: This report describes a simulator study in which seven candidate in- vehicle CAS (collision avoidance systems) were compared as to their effects on driving behavior in car-following situations. The use of the CAS systems studied is accompanied by behavioral changes affecting the way in which the driving task is performed. In general, the following effects seem to be associated with the availability of a CAS: 1) a change in the distribution of time headways, in particular a reduction in the occurrence of very short headways, 2) an increase in driving speed, 3) an increase in acceleration and deceleration levels and 4) an increase in time spend driving in the left land of the road.

Collison avoidance systems - effects of different levels of task allocation on driver behaviour

Abstract: The effects on driver behaviour, workload, and acceptance, of different levels of task allocation between a collision avoidance system (CAS) and the driver, were studied in an advanced driving simulator. Driving performance was described in terms of time headway, speed level, lateral position, and left lane driving (including overtaking behaviour). Workload was measured with the NASA-TLX questionnaire, acceptance with attitude questions. Forty subjects, between 23 and 58 years and experienced as drivers, were randomly assigned to four experimental conditions. It was found that a CAS system capable of taking over the control of the car produced the most favourable effects on drivers headway, and also reduced the number of overtakings. But, seen from the drivers point of view, that system was regarded as the most intrusive, and also most disturbing system. It was recommended that a GIDS, CAS system, should either give a warning, or suggest an appropriate action. it was also found that the use of the intelligent gas pedal, as a link between driver and CAS, did not lead to an increase of the drivers' workload. Finally, some consequences of the time to collision criteria were discussed. (A)

Traffic Alert and Collision Avoidance System (TCAS): Cockpit Display of Traffic Information (CDTI) investigation. Phase 1: Feasibility study

Abstract: The possibility of the Threat Alert and Collision Avoidance System (TCAS) traffic sensor and display being used for meaningful Cockpit Display of Traffic Information (CDTI) applications has resulted in the Federal Aviation Administration initiating a project to establish the technical and operational requirements to realize this potential. Phase 1 of the project is presented here. Phase 1 was organized to define specific CDTI applications for the terminal area, to determine what has already been learned about CDTI technology relevant to these applications, and to define the engineering required to supply the remaining TCAS-CDTI technology for capacity benefit realization. The CDTI applications examined have been limited to those appropriate to the final approach and departure phases of flight.

Safety, Reliability and Human Factors in Robotic Systems

Abstract: Overview of robot safety. Reliability and human factors. NIOSH research on robotic safety. Industrial practices for robotic safety. Development of the ANSI/RIA robot safety standard. Reliability and safety in teleoperation. Safety considerations for laboratory automation. A multilevel robot safety and collision avoidance system. An intelligent safety system for robots and automatic machines. A study of worker intrusion into robot work envelope. Reliability based control of intelligent machines.

TCAS IN THE 1990s

Abstract: The Traffic Alert and Collision Avoidance System (TCAS) is the culmination of over 30 years of work by the aviation community to develop an airborne collision avoidance system that will complement the FAA's ground-based air traffic control (ATC) system. Use of the existing ATC radar transponders provides the basis for TCAS. A collision avoidance system based on ATC transponders has the advantage that it can provide immediate, high-quality protection against the large population of aircraft already transponder-equipped. The airborne TCAS uses transponder information to track nearby aircraft. This tracking data is used to develop and display in the cockpit advisory information that advises the pilot in maneuvering to avoid threat aircraft. This paper describes the design, operation, and application of the three versions of TCAS (TCAS I, II, and III), and continuing development and implementation of TCAS during the 1990s. TCAS II is stressed since it is already in use by U.S. airlines.

Collision avoidance system concept for mobile servicing system

Abstract: The mobile servicing system (MSS) is an integrated mobile remote manipulator system under development by SPAR Aerospace Limited for the Canadian Space Agency. The MSS includes two separate manipulator systems, both possessing kinematic redundancy, and will be used in the construction and maintenance of the International Space Station Freedom. This paper presents the concepts for the collision avoidance system for these manipulators. The collision avoidance system uses a collision prediction system as a front end. The collision prediction system is based on an octree model of the environment and provides the location, direction, and distance of impending collision(s). Given the information, the system calculates the joint rate commands that will achieve automatic collision avoidance. Computer simulation of the Space Station remote manipulator system (SSRMS) operating in an octree model of the Space Station is shown, as well as hardware demonstration using a large-scale ground testbed for the special purpose dexterous manipulator (SPDM). >

Z-Basic algorithm for collision avoidance system

Abstract: A Z-Basic prediction algorithm for an aircraft ground-based collision avoidance system is presented. This system searches for mutually overlapping prediction intervals that are influenced by the aircraft's maneuver capabilities and surveillance accuracy. Z-Basic provides a powerful, fast, interactive, simple to use, and inexpensive Basic compiler. The algorithm is applied to a typical terminal airspace situation. The computer program was executed on Macintosh+, and the execution was less than one minute. The program is easy to understand and implement. >

A Collision Prediction System for a Robotic Environment

Abstract: A number of papers in the past have dealt with the formidable problem of planning a collision-free path for a robot or robotic manipulator through an environment of obstacles [see 1, 2, 3, 4].

Application of a hierarchical control structure in the implementation of a manipulator real-time collision avoidance system

Abstract: Discusses the use of hierarchical control for advanced robotic manipulators, and specifically the three layer hierarchical control system adopted by ARRL. Particular consideration is given to the tactical layer and the desired functionality within a manipulator control system, and it is shown that these functions lead to the requirement for a real-time trajectory planner embedded within the layer. The implementation of a low-level end-effector collision avoidance control system is described in the light of these considerations. The results, based on a PUMA 562 manipulator arm driven by a multiprocessor controller with ultrasonic sensing, are discussed. >