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Article
Publication date: 6 January 2012

Biyun Xie, Jing Zhao and Yu Liu

The purpose of this paper is to present a new nested rapidly‐exploring random tree (RRT) algorithm for fault tolerant motion planning of robotic manipulators.

Abstract

Purpose

The purpose of this paper is to present a new nested rapidly‐exploring random tree (RRT) algorithm for fault tolerant motion planning of robotic manipulators.

Design/methodology/approach

Another RRT algorithm is nested within the general RRT algorithm. This second nested level is used to check whether the new sampled node in the first nested level is fault tolerant. If a solution can be found in the second nested RRT, the reduced manipulator after failures at the new sampled node can still fulfill the remaining task and this new sampled node is added into the nodes of RRT in the first level. Thus, the nodes in the first level RRT algorithm are all fault tolerant postures. The final trajectory joined by these nodes is also obviously fault tolerant. Besides fault tolerance, this new nested RRT algorithm also can fulfill some secondary tasks such as improvement of dexterity and obstacle avoidance. Sufficient simulations and experiments of this new algorithm on fault tolerant motion planning of robotic manipulators are implemented.

Findings

It is found that the new nested RRT algorithm can fulfill fault tolerance and some other secondary tasks at the same time. Compared to other existing fault tolerant algorithms, this new algorithm is more efficient.

Originality/value

The paper presents a new nested RRT algorithm for fault tolerant motion planning.

Details

Industrial Robot: An International Journal, vol. 39 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 6 January 2012

Qian Li and Jing Zhao

The purpose of this paper is to propose a universal approach for configuration synthesis of reconfigurable robots based on fault tolerant indices.

Abstract

Purpose

The purpose of this paper is to propose a universal approach for configuration synthesis of reconfigurable robots based on fault tolerant indices.

Design/methodology/approach

A universal approach is introduced to determine the best configuration of redundant reconfigurable robots based on fault tolerant indices. For a given task, a method based on genetic algorithm for evaluation on the index, fault tolerant workspace reachability, is employed first to search the robot configurations with the fault tolerant ability for the desired task. Then, among the obtained robot configurations, a method based on gradient projection algorithm is adopted to further find out the robot configuration that has the comparatively best fault tolerant operation dexterity. The validity of this approach is proved by conducting computational simulations.

Findings

A universal approach has been found for configuration synthesis of reconfigurable robots based on fault tolerant indices.

Originality/value

The paper introduces a universal approach for configuration synthesis of reconfigurable robots to not only guarantee the robot with the synthesized configuration possesses the fault tolerant ability for the given task, but also has relatively high fault tolerant operation dexterity.

Details

Industrial Robot: An International Journal, vol. 39 no. 1
Type: Research Article
ISSN: 0143-991X

Keywords

Content available
Article
Publication date: 28 December 2020

Qinjie Yang, Guozhe Shen, Chao Liu, Zheng Wang, Kai Zheng and Rencheng Zheng

Steer-by-wire (SBW) system mainly relies on sensors, controllers and motors to replace the traditionally mechanical transmission mechanism to realize steering functions…

Abstract

Purpose

Steer-by-wire (SBW) system mainly relies on sensors, controllers and motors to replace the traditionally mechanical transmission mechanism to realize steering functions. However, the sensors in the SBW system are particularly vulnerable to external influences, which can cause systemic faults, leading to poor steering performance and even system instability. Therefore, this paper aims to adopt a fault-tolerant control method to solve the safety problem of the SBW system caused by sensors failure.

Design/methodology/approach

This paper proposes an active fault-tolerant control framework to deal with sensors failure in the SBW system by hierarchically introducing fault observer, fault estimator, fault reconstructor. Firstly, the fault observer is used to obtain the observation output of the SBW system and then obtain the residual between the observation output and the SBW system output. And then judge whether the SBW system fails according to the residual. Secondly, dependent on the residual obtained by the fault observer, a fault estimator is designed using bounded real lemma and regional pole configuration to estimate the amplitude and time-varying characteristics of the faulty sensor. Eventually, a fault reconstructor is designed based on the estimation value of sensors fault obtained by the fault estimator and SBW system output to tolerate the faulty sensor.

Findings

The numerical analysis shows that the fault observer can be rapidly activated to detect the fault while the sensors fault occurs. Moreover, the estimation accuracy of the fault estimator can reach to 98%, and the fault reconstructor can make the faulty SBW system to retain the steering characteristics, comparing to those of the fault-free SBW system. In addition, it was verified for the feasibility and effectiveness of the proposed control framework.

Research limitations/implications

As the SBW fault diagnosis and fault-tolerant control in this paper only carry out numerical simulation research on sensors faults in matrix and laboratory/Simulink, the subsequent hardware in the loop test is needed for further verification.

Originality/value

Aiming at the SBW system with parameter perturbation and sensors failure, this paper proposes an active fault-tolerant control framework, which integrates fault observer, fault estimator and fault reconstructor so that the steering performance of SBW system with sensors faults is basically consistent with that of the fault-free SBW system.

Details

Journal of Intelligent and Connected Vehicles, vol. 4 no. 1
Type: Research Article
ISSN: 2399-9802

Keywords

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Article
Publication date: 6 June 2008

Hu Shaolin, Sun Guoji, Ouyang Huajiang and Chen Rushan

The purpose of this paper is to present research in detecting and identifying abrupt faults in controlled auto‐regressive (CAR) processes.

Abstract

Purpose

The purpose of this paper is to present research in detecting and identifying abrupt faults in controlled auto‐regressive (CAR) processes.

Design/methodology/approach

Model‐based approach is adopted in this paper. Two series of faulttolerant iterative estimators are set up to estimate online the coefficients in a CAR process. Based on these faulttolerant estimators, the detailed detecting and identifying algorithms are obtained for not only the pulse‐type faults but also the step‐type faults in CAR process.

Findings

This paper illustrates the useful information that can be obtained from residuals and that can be used to detect pulse‐type faults as well as step‐type faults. A faulttolerant recursive estimator for the coefficients of the CAR process is put forward. Using a simple transformation from step‐ to pulse‐type faults, all kinds of diagnosis methods to detect and identify step‐type faults can be used.

Research limitations/implications

Faulttolerant estimators and fault detection and identification algorithms are aimed at abrupt faults in CAR processes.

Practical implications

Most of the algorithms given in this paper can be used in many different fields, such as process monitoring, safety control and change detection, etc.

Originality/value

This paper contributes to research of abrupt faults and abrupt changes in a CAR process and emphasizes identification of magnitudes of abrupt faults. The faulttolerant estimators are effective not only to detect faults but also to identify safely the coefficients CAR model.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 1 no. 2
Type: Research Article
ISSN: 1756-378X

Keywords

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Article
Publication date: 4 March 2014

Yuji Sato and Mikiko Sato

The purpose of this paper is to propose a fault-tolerant technology for increasing the durability of application programs when evolutionary computation is performed by…

Abstract

Purpose

The purpose of this paper is to propose a fault-tolerant technology for increasing the durability of application programs when evolutionary computation is performed by fast parallel processing on many-core processors such as graphics processing units (GPUs) and multi-core processors (MCPs).

Design/methodology/approach

For distributed genetic algorithm (GA) models, the paper proposes a method where an island's ID number is added to the header of data transferred by this island for use in fault detection.

Findings

The paper has shown that the processing time of the proposed idea is practically negligible in applications and also shown that an optimal solution can be obtained even with a single stuck-at fault or a transient fault, and that increasing the number of parallel threads makes the system less susceptible to faults.

Originality/value

The study described in this paper is a new approach to increase the sustainability of application program using distributed GA on GPUs and MCPs.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 7 no. 1
Type: Research Article
ISSN: 1756-378X

Keywords

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Article
Publication date: 2 January 2018

Hidenobu Matsuki, Taishi Nishiyama, Yuya Omori, Shinji Suzuki, Kazuya Masui and Masayuki Sato

This paper aims to demonstrate the effectiveness of a fault-tolerant flight control method by using simple adaptive control (SAC) with PID controller.

Abstract

Purpose

This paper aims to demonstrate the effectiveness of a fault-tolerant flight control method by using simple adaptive control (SAC) with PID controller.

Design/methodology/approach

Numerical simulations and flight tests are executed for pitch angle and roll angle control of research aircraft MuPAL-α under the following fault cases: sudden reduction in aileron effectiveness, sudden reduction in elevator effectiveness and loss of longitudinal static stability.

Findings

The simulations and flight tests reveal the effectiveness of the proposed SAC with PID controller as a fault-tolerant flight controller.

Practical implications

This research includes implications for the development of vehicles’ robustness.

Originality/value

This study proposes novel SAC-based flight controller and actually demonstrates the effectiveness by flight test.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 1
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 1 September 2006

Mehmet Dede and Sabri Tosunoglu

The objective of this study is to enhance the usage of teleoperation fields, such as in nuclear site decommissioning or nuclear waste disposal, by designing a stable…

Abstract

Purpose

The objective of this study is to enhance the usage of teleoperation fields, such as in nuclear site decommissioning or nuclear waste disposal, by designing a stable, dependable and faulttolerant teleoperation system in the face of “extraordinary” conditions. These “extraordinary” conditions can be classified as variable time delays in communications lines, usage of different robotic systems, component failures and changes in the system parameters during task execution.

Design/methodology/approach

This paper first gives a review of teleoperation systems developed earlier. Later, fault tolerance is proposed for use in teleoperation systems at the processor, actuator, sub‐system, and system levels. Position/force control algorithms are recommended to address stability issues when there is a loss in communications. Various other controls are also introduced to overcome the instability experienced when there is a time delay in the communications line.

Findings

Finally, this work summarizes the teleoperation system architecture and controller design options in terms of a flowchart to help in the conceptual design of such systems.

Originality/value

The impact of these new designs and algorithms will be to expand the limits and boundaries of teleoperation and a widening of its utilization area. Enhanced operation of these systems will improve system reliability and even encourage their use in more critical and diverse applications.

Details

Industrial Robot: An International Journal, vol. 33 no. 5
Type: Research Article
ISSN: 0143-991X

Keywords

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Article
Publication date: 4 January 2016

Dan Xu, James Ferris Whidborne and Alastair Cooke

The growing use of small unmanned rotorcraft in civilian applications means that safe operation is increasingly important. The purpose of this paper is to investigate the…

Abstract

Purpose

The growing use of small unmanned rotorcraft in civilian applications means that safe operation is increasingly important. The purpose of this paper is to investigate the fault tolerant properties to faults in the actuators of an C 1 adaptive controller for a quadrotor vehicle.

Design/methodology/approach

C 1 adaptive control provides fast adaptation along with decoupling between adaptation and robustness. This makes the approach a suitable candidate for fault tolerant control of quadrotor and other multirotor vehicles. In the paper, the design of an C 1 adaptive controller is presented. The controller is compared to a fixed-gain LQR controller.

Findings

The C 1 adaptive controller is shown to have improved performance when subject to actuator faults, and a higher range of actuator fault tolerance.

Research limitations/implications

The control scheme is tested in simulation of a simple model that ignores aerodynamic and gyroscopic effects. Hence for further work, testing with a more complete model is recommended followed by implementation on an actual platform and flight test. The effect of sensor noise should also be considered along with investigation into the influence of wind disturbances and tolerance to sensor failures. Furthermore, quadrotors cannot tolerate total failure of a rotor without loss of control of one of the degrees of freedom, this aspect requires further investigation.

Practical implications

Applying the C 1 adaptive controller to a hexrotor or octorotor would increase the reliability of such vehicles without recourse to methods that require fault detection schemes and control reallocation as well as providing tolerance to a total loss of a rotor.

Social implications

In order for quadrotors and other similar unmanned air vehicles to undertake many proposed roles, a high level of safety is required. Hence the controllers should be fault tolerant.

Originality/value

Fault tolerance to partial actuator/effector faults is demonstrated using an C 1 adaptive controller.

Details

International Journal of Intelligent Unmanned Systems, vol. 4 no. 1
Type: Research Article
ISSN: 2049-6427

Keywords

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Article
Publication date: 2 May 2017

Isil Yazar, Fikret Caliskan and Emre Kiyak

Condition monitoring and health management of an aircraft engine is of importance due to engine’s critical position in aircraft. Missions require uninterrupted and safer…

Abstract

Purpose

Condition monitoring and health management of an aircraft engine is of importance due to engine’s critical position in aircraft. Missions require uninterrupted and safer conditions during the flight or taxi operations. Hence, the deviations, abnormal situations or failures have to be under control. This paper aims to propose a cascade connected approach for an aircraft engine fault tolerant control.

Design/methodology/approach

The cascade connected structure includes a full-order unknown input observer for fault detection and eliminating the unknown disturbance effect on system, a generalized observer scheme for fault isolation and a Boolean logic mechanism for decision-making in reconfiguration process, respectively. This combination is simulated on a linear turbojet engine model in case of unknown input disturbance and under various sensor failure scenarios.

Findings

The simulation results show that the suggested fault detection isolation reconfiguration (FDIR) approach works effectively for multiple sensor failures with various amplitudes.

Originality/value

Different from other studies, the proposed model is sensitive to unknown input disturbance and failures that have unknown amplitudes. One another notable feature of suggested FDIR approach is adaptability of structure against multiple sensor failures. Here, it is assumed that only a single fault is to be detected and isolated at a time. The simulation results show that the proposed structure can be suggested for linear models especially for physical redundancy-based real-time applications easily, quickly and effectively.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 7 August 2020

Seyyed Javad Seyyed Mahdavi Chabok and Seyed Amin Alavi

The routing algorithm is one of the most important components in designing a network-on-chip (NoC). An effective routing algorithm can cause better performance and…

Abstract

Purpose

The routing algorithm is one of the most important components in designing a network-on-chip (NoC). An effective routing algorithm can cause better performance and throughput, and thus, have less latency, lower power consumption and high reliability. Considering the high scalability in networks and fault occurrence on links, the more the packet reaches the destination (i.e. to cross the number of fewer links), the less the loss of packets and information would be. Accordingly, the proposed algorithm is based on reducing the number of passed links to reach the destination.

Design/methodology/approach

This paper presents a high-performance NoC that increases telecommunication network reliability by passing fewer links to destination. A large NoC is divided into small districts with central routers. In such a system, routing in large routes is performed through these central routers district by district.

Findings

By reducing the number of links, the number of routers also decreases. As a result, the power consumption is reduced, the performance of the NoC is improved, and the probability of collision with a faulty link and network latency is decreased.

Originality/value

The simulation is performed using the Noxim simulator because of its ability to manage and inject faults. The proposed algorithm, XY routing, as a conventional algorithm for the NoC, was simulated in a 14 × 14 network size, as the typical network size in the recent works.

Details

World Journal of Engineering, vol. 17 no. 5
Type: Research Article
ISSN: 1708-5284

Keywords

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