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THE general theorems given in Sections 4 and 6 include, from the fundamental point of view, all that is required for the analysis of redundant structures. However, to facilitate practical calculations it is helpful to develop more explicit methods and formulae. To find these is the purpose of this Section.

Stiffness control of redundant robot arm, aimed at using extra degrees of freedom (DoF) to shape the robot tool center point (TCP) elastomechanical behavior to be consistent with the essential requirements needed for a successful part mating process, i.e., to mimic part supporting mechanism with selective quasi-isotropic compliance (Remote Center of Compliance – RCC), with additional properties of inherent flexibility.

Theoretical analysis and synthesis of the complementary projector for null-space stiffness control of kinematically redundant robot arm. Practical feasibility of the proposed approach was proven by extensive computer simulations and physical experiments, based on commercially available 7 DoF SIA 10 F Yaskawa articulated robot arm, equipped with the open-architecture control system, system for generating excitation force, dedicated sensory system for displacement measurement and a system for real-time acquisition of sensory data.

Simulation experiments demonstrated convergence and stability of the proposed complementary projector. Physical experiments demonstrated that the proposed complementary projector can be implemented on the commercially available anthropomorphic redundant arm upgraded with open-architecture control system and that this projector has the capacity to efficiently affect the task-space TCP stiffness of the robot arm, with a satisfactory degree of consistency with the behavior obtained in the simulation experiments.

A novel complementary projector was synthesized based on the adopted objective function. Practical verification was conducted using computer simulations and physical experiments. For the needs of physical experiments, an adequate open-architecture control system was developed and upgraded through the implementation of the proposed complementary projector and an adequate system for generating excitation and measuring displacement of the robot TCP. Experiments demonstrated that the proposed complementary projector for null-space stiffness control is capable of producing the task-space TCP stiffness, which can satisfy the essential requirements needed for a successful part-mating process, thus allowing the redundant robot arm to mimic the RCC supporting mechanism behavior in a programmable manner.

The purpose of this paper is to design a special automatic redundant robot painting system (RRPS), which can automatically navigate and paint in the long non-regular duct.

The RRPS is designed with three subsystems: a redundant robot, a spraying system and a control and safety system. Based on the modular design theory, the robot falls naturally into a mobile platform, a 4-DOF location mechanism and a 10-DOF manipulator. The restriction of the distance between the links and the duct axis is used to plan the trajectory of the manipulator so that it would not collide with the duct. The restriction model is constructed by minimizing the sum of the weighed distances between the duct axis and the special points.

A fully working prototype system has been developed. Test results show that the minimal distance between the robot joints and duct is 18 mm, and it can finish painting long non-regular ducts at the speed of 12.5 cm/s and the spraying distance of 16 cm. The quality of coating layers is good.

The RRPS was used to paint non-regular rectangular ducts, cylindrical ducts and long non-regular ducts. The feasibility of painting long non-regular duct is proved with the prototype implementation and successful test results.

The RRPS shows a novel solution that is based on the 14-DOF redundant robot design for painting long non-regular ducts which is used in airplane.

HAVING discussed in the standard longhand notation the main ideas and methods for the calculation of redundant structures on the basis of forces as unknowns we now turn our attention to the matrix formulation of the analysis. Consider a system consisting of s structural elements with a total number n of redundancies which may be forces (stresses), moments or any generalized forces. We select a basic system by ‘cutting’ a number r of redundancies where r<n. Thus, the simple idea of a statically determinate basic system (r=n) is but a particular case of our investigations.

The purpose of this paper is to propose a condition-based opportunistic maintenance policy considering economic dependence for a series–parallel hybrid system with a K-out-of-N redundant structure, where a single component in series is denoted as subsystem1, and K-out-of-N redundant structure is denoted as subsystem2.

Based on the theory of Residual Useful Life (RUL), inspection points are determined, and then different maintenance actions are adopted in the purpose of minimizing the cost rate. Both perfect and imperfect maintenance actions are carried out for subsystem1. More significantly, regarding economic dependence, condition-based opportunistic maintenance is designed for the series–parallel hybrid system: preemptive maintenance for subsystem1, and both preemptive and postponed maintenance for subsystem2.

The sensitivity analysis indicates that the proposed policy outperforms two classical maintenance policies, incurring the lowest total cost rate under the context of both heterogeneous and quasi-homogeneous K-out-of-N subsystems.

This model can be applied in series–parallel systems with redundant structures that are widely used in power transmission systems in electric power plants, manufacturing systems in textile factories and sewerage systems. Considering inconvenience and high cost incurred in the inspection of hybrid systems, this model helps production managers better maintain these systems.

In maintenance literature, much attention has been received in repairing strategies on hybrid systems with economic dependence considering preemptive maintenance. Limited work has considered postponed maintenance. However, this paper uses both condition-based preemptive and postponed maintenance on the issue of economic dependence bringing opportunities for grouping maintenance activities for a series–parallel hybrid system.

High-reliability performance and high-hazard are intertwined in High-Reliability Organizations (HROs) operations; these organizations are highly safe, highly hazardous and highly significant for the modern society, not only for the valuable resources they have, but also the indispensable services they provide. This research intend to understand how HROs could produce high quality performance despite their challenging and demanding contexts. The research followed an emic approach to develop an organizational framework that reflects the contribution of the seeming traits of the organizations to the operations safety based on the workers point of views about the safety of workstations.

This research adopted mixed methods of in-depth interviews and literature review to identify the structural characteristics of high-reliability organizations (HROs) embedded in the organizations studies and developed a theoretical based structural framework for HROs. Furthermore, a systemic literature review was adopted to find the evidence from the organizations literature for the identified characteristics from the interviews from the first stage. The setting for this study is six Chinese power stations, four stations in Hubei province central China and two stations in the southern China Guangdong province.

The organizational framework is a key determinant to achieve high-reliability performance; however, solely it cannot explain how HROs manage the risks of hazard events and operate safely in high-hazard environments. High-reliability performance is attributed to the interaction between two sets of determinants of safety and hazard. The findings of this research indicate that HROs systems would be described as reliable or hazardous depending on the tightly coupled setting, complexity, bureaucracy involvement and dynamicity within the systems from one hand, and safety orientation, failure intolerance, systemwide processing, the institutional setting and the employment of redundant systems on other hand.

The authors developed an organizational framework of organizing the safety work in HROs. The applied method of interviewing and literature review was not adopted in any other researches.

A series of examples illustrates the application and results of the method previously given for improving the conditioning of the primary redundancies. The transformation matrix giving locally orthogonal redundancies for the parent station is used also to generate the primary self‐equilibrating stress systems for sections with different (but related) geometry and varying ring stiffness. A double‐cell cross‐section is also treated and a brief investigation shows that the general methods developed for establishing primary redundancies in the fuselage can be usefully and economically applied to certain kinds of wing structure. Preparatory to a detailed discussion of cut‐outs and modifications in the fuselage structure, the necessary general theory is collected and summarized.

The purpose of this paper is to examine the cost/benefit (C/B) analysis of four configurations for a repairable system with two primary components/units and one standby.

The four configurations are set to the status of the detection and switching failure of standby, as well as the possible reboot of failed units. The time to failure for each of the primary and standby is assumed to follow an exponential distribution. The time to repair and the time to reboot is assumed to have a k‐stage Erlang distribution. The paper develops the explicit expressions of the mean time to failure (or MTTF) and the steady‐state availability (or A) for four various configurations and performed some comparative analysis. Based on the C/B criterion, comparisons are made for specific values of distribution parameters and of the costs of the units. The four various configurations for a repairable system are ranked by using MTTF, A and C/B, where B is either MTTF or A.

Although it is uncertain which configuration is the optimal one among the four ones, the paper provides much comparative information to manager and manufacturers. Managers can use these results to choose the best configuration according to the used data of parameters and selections of the weight of MTTF or Cost/MTTF.

This paper shows a comparative analysis for a two‐unit online repairable system with one standby under four different configurations. It is the first discussion of comparable work on reliability and availability models for redundant repairable systems in which the units are characterized by detection, switching failure and reboot.

Points out the steadily growing role of computers in the industrial sector. Highlights some accidents involving robots and touches on safeguards which have been introduced. Presents reliability and availability analysis of a robot machine/system having a redundant safety system. Formulas for system reliability, steady state availability, and mean time to failure are developed. Selective plots of the resulting formulas are shown.

The purpose of this paper is to derive a closed-form expression for the steady-state availability of a cold standby repairable k-out-of-n system. This makes the availability calculation much easier and accurate.

Assuming exponential distributions for system failure and repair, the Markov method is employed to derive the formula.

The proposed formula establishes an easier and faster venue and provides accurate steady-state availability.

The formula is valid for the case when the probability density function of the component failure and the repair is exponential.

The Markov method has never been used in the literature to derive the steady-state availability of a cold standby repairable k-out-of-n: G system.