Fault tolerance via analytic redundancy for a modularized sensitive skin

Um, Dugan; Lumelsky, V.

doi:10.1109/iros.1999.812841

Cited by 7 publications

(6 citation statements)

References 3 publications

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“…In this case, the original sensor resolution can be kept intact for full functionality of the sensory array. As is discussed in the previous literature [14], the AR-based tolerance scheme demonstrated useful results for sensitive skin fault tolerance. In this paper, however, we focus on the integration of component and analytic redundancy as a complete embodiment for massive sensor array faulttolerance architecture.…”

Section: Introductionmentioning

confidence: 63%

“…The voting scheme, however, does not isolate a faulty sensor since the proposed voting scheme implicitly neutralizes faulty sensors. In the previous literature [14], a fault isolation technique by analytic redundancy is demonstrated to show how to isolate a faulty sensor in a massive sensor array for maximum resolution or for immediate repair during the maintenance period. In brief, since the skin sensors are attached on the robot, sensors move when the robot is in motion.…”

Section: Fault Detection By Analytic Redundancymentioning

confidence: 99%

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Massive Sensor Array Fault Tolerance: Tolerance Mechanism and Fault Injection for Validation

2010

Journal of Robotics

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As today's machines become increasingly complex in order to handle intricate tasks, the number of sensors must increase for intelligent operations. Given the large number of sensors, detecting, isolating, and then tolerating faulty sensors is especially important. In this paper, we propose fault tolerance architecture suitable for a massive sensor array often found in highly advanced systems such as autonomous robots. One example is the sensitive skin, a type of massive sensor array. The objective of the sensitive skin is autonomous guidance of machines in unknown environments, requiring elongated operations in a remote site. The entirety of such a system needs to be able to work remotely without human attendance for an extended period of time. To that end, we propose a fault-tolerant architecture whereby component and analytical redundancies are integrated cohesively for effective failure tolerance of a massive array type sensor or sensor system. In addition, we discuss the evaluation results of the proposed tolerance scheme by means of fault injection and validation analysis as a measure of system reliability and performance.

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Section: Introductionmentioning

confidence: 63%

Section: Fault Detection By Analytic Redundancymentioning

confidence: 99%

Massive Sensor Array Fault Tolerance: Tolerance Mechanism and Fault Injection for Validation

2010

Journal of Robotics

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“…Equations (19)- (21) represent the conditions that must hold for erroneous convergence. For a given failure angle of a joint, these equations can be solved for the other joint variables to determine the problematic configurations.…”

Section: Conditions For Erroneous Convergencementioning

confidence: 99%

“…These stationary configurations represent the set of seed configurations that are grown to trace out the entire stationary manifold. Since (19)- (21) must hold at all stationary configurations, the loci of stationary configurations can be traced by simply starting at a seed that satisfies these conditions, and moving in a direction orthogonal to the gradients of the right-hand side components of these equations. Doing this for each seed allows all the loci to be traced.…”

Section: Tracing and Classifying Stationary Manifoldsmentioning

confidence: 99%

“…Existing failure tolerance schemes rely on effective failure detection and identification; [14][15][16] only after a failure is identified is an appropriate failure recovery strategy initiated. [17][18][19][20][21] However, failure identification is itself a difficult process that may not always be successful. 3,22 While it is easy to envision a failure recovery strategy for identified failures, the situation is much more difficult when a failure is merely detected, but not identified.…”

Section: Introductionmentioning

confidence: 99%

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Analyzing unidentified locked-joint failures in kinematically redundant manipulators

2004

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Robots are frequently used for operations in hostile environments. The very nature of these environments, however, increases the likelihood of robot failures. Common failuretolerance techniques rely on effective failure detection and identification. Since a failure may not always be successfully identified, or, even if identified, may not be identified soon enough, it becomes important to consider the behavior of manipulators with unidentified failures. This work investigates the behavior of robots experiencing unidentified locked-joint failures in a general class of tasks characterized by point-to-point motion. Based on the analysis, a procedure for workspace evaluation is developed that allows for the identification of regions in the manipulator's workspace in which tasks may be completed even with such failures. where xe R" is the position of the end effector, q eRn is the vector of joint variables, and m and n the dimensions of the task space and joint space, teepeetively. Manipulators that have more degrees of freedom (DOFs) than required for a task, i.e., n>m, are said to be redundant. 'The end-effector velocity is expressed in terms of the joint rates as where] E H m X n is the manipulator Jacobian, xis the end-effector velocity, and it is the joint velocity.If perfect servo control of the joints is assumed, then in a healthy manipulator the actual joint velodfailed, the ability of manipulators to converge to desired end-effector positions even with imperfect/ approximated lacobtana/Iacobian-inverses has been addressed in refs. 26 and 27. Therefore, we focus on the other case where a joint has actually locked, but the controller continues to command motion of that joint as though it were healthy. For a general class of tasks characterized by point-to-point motion, we examine convergence issues such as whether the manipulator comes to rest and, if so, what is the terminal position and orientation of the end-effector. The convergence analysis is restricted to purely kinematic effects, due to the fact that the dynamic effects of a failure are essentially transient in nature and do not significantly affect the convergence behavior. 18.28 -3 0 Conditions under which the manipulator converges are explicitly defined and the anomalies in behavior due to the faults explained and illustrated with examples. These conditions are used to evaluate the convergence behavior of the manipulator over the postfailure workspace. This allows for the identification of workspace regions for which task completion may be possible even with unidentified failures.The position and orientation-of the end effector of a manipulator can be expressed in terms of its joint variables by the kinematic equation "nus assumes a typical commercial robot where duplicate sensing and/or analytical redundancy does not exist.

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Distributed multi-agent diagnosis and recovery from sensor failures

Long

Murphy

Parker³

Proceedings 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2003) (Cat. No.03CH37453)

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This paper presents work extending previous research in sensor fault tolerance, classification, and recovery from a single robot to a heterogeneous team of distributed robots. This approach allows teams of robots to share knowledge about the working environment, sensor and task state, to diagnose failures and also communicate to redistribute tasks in the event that a robot becomes inoperable. Our work presents several novel extensions to prior art: distributed fault handling and task management in a dynamic, distributed Java framework. This research was implemented and demonstrated on robots in a lab environment performing a simplified search operation.

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Fault tolerance via analytic redundancy for a modularized sensitive skin

Cited by 7 publications

References 3 publications

Massive Sensor Array Fault Tolerance: Tolerance Mechanism and Fault Injection for Validation

Massive Sensor Array Fault Tolerance: Tolerance Mechanism and Fault Injection for Validation

Analyzing unidentified locked-joint failures in kinematically redundant manipulators

Distributed multi-agent diagnosis and recovery from sensor failures

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