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Article
Publication date: 1 June 2012

Yin Lili, Zhang Rubo and Gu Hengwen

The purpose of this paper is to provide a more capable and holistic adjustable autonomy system, involving situation reasoning among all involved information sources, to make an…

Abstract

Purpose

The purpose of this paper is to provide a more capable and holistic adjustable autonomy system, involving situation reasoning among all involved information sources, to make an adjustable autonomy system which knows what the situation is currently, what needs to be done in the present situation, and how risky the task is in the present situation. This will enhance efficiency for calculating the level of autonomy.

Design/methodology/approach

Situation reasoning methodologies are present in many autonomous systems which are called situation awareness. Situation awareness in autonomous systems is divided into three levels, situation perception, situation comprehension and situation projection. Situation awareness in these systems aims to make the tactical plans cognitive, but situation reasoning in adjustable autonomous systems aim to communicate mission assessments to unmanned vehicle or humans. Thus, in solving this problem, it is important to design a new situation reasoning module for the adjustable autonomous system.

Findings

The contribution of this paper is presenting the Situation Reasoning Module (SRM) for an adjustable autonomous system, which encapsulates event detection, cognitive situations, cognitive tasks, performance capacity assessment and integrated situation reason. The paper concludes by demonstrating the benefits of the SRM in a real‐world scenario, a situation reasoning simulation in unmanned surface vehicles (USV) while performing a navigation mission.

Originality/value

The method presented in this paper represents a new SRM to reason the situation for adjustable autonomous system. While the results presented in the paper are based on fuzzy logic and Bayesian network methodology. The results of this paper can be applicable to land, sea and air robotics in an adjustable autonomous system.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 5 no. 2
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 13 November 2017

Salama A. Mostafa, Mohd Sharifuddin Ahmad, Aida Mustapha and Mazin Abed Mohammed

The purpose of this paper is to propose a layered adjustable autonomy (LAA) as a dynamically adjustable autonomy model for a multi-agent system. It is mainly used to efficiently…

Abstract

Purpose

The purpose of this paper is to propose a layered adjustable autonomy (LAA) as a dynamically adjustable autonomy model for a multi-agent system. It is mainly used to efficiently manage humans’ and agents’ shared control of autonomous systems and maintain humans’ global control over the agents.

Design/methodology/approach

The authors apply the LAA model in an agent-based autonomous unmanned aerial vehicle (UAV) system. The UAV system implementation consists of two parts: software and hardware. The software part represents the controller and the cognitive, and the hardware represents the computing machinery and the actuator of the UAV system. The UAV system performs three experimental scenarios of dance, surveillance and search missions. The selected scenarios demonstrate different behaviors in order to create a suitable test plan and ensure significant results.

Findings

The results of the UAV system tests prove that segregating the autonomy of a system as multi-dimensional and adjustable layers enables humans and/or agents to perform actions at convenient autonomy levels. Hence, reducing the adjustable autonomy drawbacks of constraining the autonomy of the agents, increasing humans’ workload and exposing the system to disturbances.

Originality/value

The application of the LAA model in a UAV manifests the significance of implementing dynamic adjustable autonomy. Assessing the autonomy within three phases of agents run cycle (task-selection, actions-selection and actions-execution) is an original idea that aims to direct agents’ autonomy toward performance competency. The agents’ abilities are well exploited when an incompetent agent switches with a more competent one.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 10 no. 4
Type: Research Article
ISSN: 1756-378X

Keywords

Article
Publication date: 4 January 2011

Grzegorz Iwanski

Wind‐diesel sets offered as a reliable hybrid isolated power systems with reduction of fuel consumption, consists of variable speed wind turbines and fixed speed diesel engines…

Abstract

Purpose

Wind‐diesel sets offered as a reliable hybrid isolated power systems with reduction of fuel consumption, consists of variable speed wind turbines and fixed speed diesel engines. Load and wind energy variations cause, that the load power of the diesel genset is varied in wide range. Fixed speed generation set operates with the best efficiency only in a narrow range of the load, therefore implementation of a load adaptive, adjustable speed genset may additionally reduce fuel consumption.

Design/methodology/approach

Analysis of the system components model, simulation and laboratory tests on a small‐scale model.

Findings

Topology and output voltage control method of four‐wire adjustable speed autonomous wind‐diesel system dedicated for isolated power plants with high wind penetration.

Research limitations/implications

The paper presents only part of the work which has to be done for the complete system. Load and energy management has to be applied in standalone system, as not in each operating point of proposed wind‐diesel system, can rated load be supplied. To fully prove the proposed system and control concept, tests of megawatt range system are advisable. To evaluate the fuel saving, a real wind and load profile in a selected isolated place is needed.

Practical implications

Every adjustable speed generation systems can save fuel. However, proposed topology in main part consists of known and implemented solutions, therefore costs of the new installation will not be increased significantly.

Originality/value

Proposed costs effective topology of adjustable speed wind‐diesel generation system has not been presented by any other authors. Standalone operation of doubly fed induction generator system is rarely reported in the papers.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 January 2012

Grzegorz Iwanski and Gonzalo Abad

Doubly fed induction generator DFIG applied in over 50 percent of modern variable speed wind power systems and interesting also for adjustable speed diesel generation sets or…

Abstract

Purpose

Doubly fed induction generator DFIG applied in over 50 percent of modern variable speed wind power systems and interesting also for adjustable speed diesel generation sets or multi‐megawatt water turbines is troublesome in the mean of maintenance of slip‐rings and brushes. Especially, it concerns isolated power systems and offshore wind turbines. Application of brushless DFIG in such cases eliminates the mentioned problem. Constructions of the machine and consequently the model and mathematical description is more complicated than classical slip‐ring DFIG, therefore it is still developed in several scientific institutions to obtain adequate performance. The following work is dedicated to mathematical description, modelling and implementation of the control method for autonomous operation in the laboratory model of brushless DFIG.

Design/methodology/approach

Analysis and simulation of the machine model and laboratory tests on a small scale prototype of brushless DFIG.

Findings

It has been proven that sensorless direct voltage control of DFIG can be applied for both slip‐ring and brushless machines, as it does not require machine parameters.

Research limitations/implications

Brushless DFIG development is far from the performance needed by industrial implementation. Lower efficiency and higher reactive power needed by the machine, in comparison to classical DFIG of the same power range, result from double air gap seen by magnetic flux. However, the constructions of prototype machines are better and better, and their capabilities become closer to DFIG.

Practical implications

Variable and adjustable speed generation systems such as wind turbines, diesel generation sets, water turbines.

Originality/value

Standalone power systems with DFIG described in several papers require quite complicated control methods based on the mathematical equations of the machine model. Thus, these methods have to be significantly modified for the brushless version of this machine type, due to the fact of a much more complicated model. The proposed sensorless method of the output voltage control requires only redesign (tuning) of the PI controllers responsible for control of the rotor current, stator voltage amplitude and frequency.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 12 September 2008

Wlodzimierz Koczara, Zdzislaw Chlodnicki, Emil Ernest, Artur Krasnodebski, Robert Seliga, Neil L. Brown, Bartlomiej Kaminski and Jawad Al‐Tayie

The purpose of this paper is to provide a new theory of adjustable speed decoupled generation which has the potential to challenge existing coupled generation based on a classical…

Abstract

Purpose

The purpose of this paper is to provide a new theory of adjustable speed decoupled generation which has the potential to challenge existing coupled generation based on a classical synchronous generator operating with fixed speed.

Design/methodology/approach

The paper's approach is a theoretical consideration of the drawbacks of conventional fixed speed generation based on a synchronous generator and proposal of problem solutions by the introduction of a decoupled generation system with additional degree of freedom. Computer calculations are used as design and for preliminary verification. Tests in a real laboratory system equipped with modern components such as electrical machines and power electronic converters proved the theory.

Findings

Decoupled generation is realized in a very original way using new blocks, integration method and control. The developed system has been awarded more than six world patents. The system has additional degrees of freedom in speed and grid connection operation.

Originality/value

The research team has concentrated its research over many years and developed a generation system which has been awarded a great number of patents. A special axial flux, light and simple permanent magnet generator was developed and integrated to the prime mover. A three‐phase AC/AC power electronic converter and a DSP controller are integrated to a very small size and low weight. The invented topology provides a very reliable operation, high‐quality AC voltage in fully three‐phase non‐symmetrical load. There were also presentations on world conferences (EPE, PESC, EPE‐PEMC).

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 27 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 5 May 2021

Haina Song, Shengpei Zhou, Zhenting Chang, Yuejiang Su, Xiaosong Liu and Jingfeng Yang

Autonomous driving depends on the collection, processing and analysis of environmental information and vehicle information. Environmental perception and processing are important…

Abstract

Purpose

Autonomous driving depends on the collection, processing and analysis of environmental information and vehicle information. Environmental perception and processing are important prerequisite for the safety of self-driving of vehicles; it involves road boundary detection, vehicle detection, pedestrian detection using sensors such as laser rangefinder, video camera, vehicle borne radar, etc.

Design/methodology/approach

Subjected to various environmental factors, the data clock information is often out of sync because of different data acquisition frequency, which leads to the difficulty in data fusion. In this study, according to practical requirements, a multi-sensor environmental perception collaborative method was first proposed; then, based on the principle of target priority, large-scale priority, moving target priority and difference priority, a multi-sensor data fusion optimization algorithm based on convolutional neural network was proposed.

Findings

The average unload scheduling delay of the algorithm for test data before and after optimization under different network transmission rates. It can be seen that with the improvement of network transmission rate and processing capacity, the unload scheduling delay decreased after optimization and the performance of the test results is the closest to the optimal solution indicating the excellent performance of the optimization algorithm and its adaptivity to different environments.

Originality/value

In this paper, the results showed that the proposed method significantly improved the redundancy and fault tolerance of the system thus ensuring fast and correct decision-making during driving.

Details

Assembly Automation, vol. 41 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

Abstract

Details

The Handbook of Road Safety Measures
Type: Book
ISBN: 978-1-84855-250-0

Article
Publication date: 1 September 2002

Derek W. Seward

The adaptation of conventional robots to construction sites is fraught with problems. Most significant of these are in relation to positioning, means of collision avoidance, and…

Abstract

The adaptation of conventional robots to construction sites is fraught with problems. Most significant of these are in relation to positioning, means of collision avoidance, and appropriate navigation strategy. This paper reviews the different levels of navigational autonomy that are possible and describes the system requirements for each. A taxonomy based on the concept of a Mobility Automation Level (MAL) is proposed. Each level is described and the requirements from a robot design perspective are discussed. Finally, a case study, based on an excavator with autonomously optimised movement, known as LUCIE, is used to illustrate some of the design criteria previously described and discussed.

Details

Construction Innovation, vol. 2 no. 3
Type: Research Article
ISSN: 1471-4175

Keywords

Article
Publication date: 3 May 2010

Maleachi Bühringer, Jan Berchtold, Melanie Büchel, Claus Dold, Michael Bütikofer, Mevina Feuerstein, Wolfgang Fischer, Christian Bermes and Roland Siegwart

The purpose of this paper is to describe the design and prototype implementation of the “Cable Crawler”, a mobile teleoperated robot for the inspection of high‐voltage power lines…

Abstract

Purpose

The purpose of this paper is to describe the design and prototype implementation of the “Cable Crawler”, a mobile teleoperated robot for the inspection of high‐voltage power lines which rides on the topmost ground cable. By not being limited to just moving from mast to mast, it implements an innovative mechanism that allows for crossing a set of mast tops as well as smaller obstacles autonomously.

Design/methodology/approach

After a brief overview of the state‐of‐the‐art for this application, the basic concept of the robot is presented – which basically consists of a chassis and six motorized rubber‐coated rollers, two in a horizontal position to take the weight and four vertical ones. The four vertical rollers are pressed onto the wire by springs, which guarantees slip‐less propulsion in difficult situations. The detailed design of the most challenging components is presented, as well as the successful tests with the prototype.

Findings

The feasibility of the concept is proven with a prototype implementation and successful test results.

Practical implications

With a mass of 58 kg and only six drives, it consequently follows the industry's wish to have a robust, easy to maintain and rather cheap solution. Regarding the fields examined by the robot, the project concentrated on the detection of trees growing into proximity of the wires. Future work will mainly stress in further reducing the robot's mass and in facilitating its transport to the mast by the workers.

Originality/value

The presented prototype allows for moving on the topmost ground cable of high‐voltage power‐lines and to passively roll over mast tops and smaller obstacles. With these properties, it is able to inspect long distances of cables in an autonomous way and by using a relatively low‐cost and robust robot.

Details

Industrial Robot: An International Journal, vol. 37 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 26 September 2019

Ruochen Tai, Jingchuan Wang and Weidong Chen

In the running of multiple automated guided vehicles (AGVs) in warehouses, delay problems in motions happen unavoidably as there might exist some disabled components of robots…

Abstract

Purpose

In the running of multiple automated guided vehicles (AGVs) in warehouses, delay problems in motions happen unavoidably as there might exist some disabled components of robots, the instability of networks and the interference of people walking. Under this case, robots would not follow the designed paths and the coupled relationship between temporal and space domain for paths is broken. And there is no doubt that other robots are disturbed by the ones where delays happen. Finally, this brings about chaos or even breakdown of the whole system. Therefore, taking the delay disturbance into consideration in the path planning of multiple robots is an issue worthy of attention and research.

Design/methodology/approach

This paper proposes a prioritized path planning algorithm based on time windows to solve the delay problems of multiple AGVs. The architecture is a unity consisting of three components which are focused on scheduling AGVs under normal operations, delays of AGVs, and recovery of AGVs. In the components of scheduling AGVs under normal operations and recovery, this paper adopts a dynamic routing method based on time windows to ensure the coordination of multiple AGVs and efficient completion of tasks. In the component for scheduling AGVs under delays, a dynamical prioritized local path planning algorithm based on time windows is designed to solve delay problems. The introduced planning principle of time windows would enable the algorithm to plan new solutions of trajectories for multiple AGVs, which could lower the makespan. At the same time, the real-time performance is acceptable based on the planning principle which stipulates the parameters of local time windows to ensure that the computation of the designed algorithm would not be too large.

Findings

The simulation results demonstrate that the proposed algorithm is more efficient than the state-of-the-art method based on homotopy classes, which aims at solving the delay problems. What is more, it is validated that the proposed algorithm can achieve the acceptable real-time performance for the scheduling in warehousing applications.

Originality/value

By introducing the planning principle and generating delay space and local adjustable paths, the proposed algorithm in this paper can not only solve the delay problems in real time, but also lower the makespan compared with the previous method. The designed algorithm guarantees the scheduling of multiple AGVs with delay disturbance and enhances the robustness of the scheduling algorithm in multi-AGV system.

Details

Assembly Automation, vol. 39 no. 5
Type: Research Article
ISSN: 0144-5154

Keywords

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