Mechanical Backup Research Articles

Convolution-LSTM-Based Mechanical Hard Disk Failure Prediction by Sensoring S.M.A.R.T. Indicators

The traditional Infrastructure as a Service (IaaS) cloud platform tends to realize high data availability by introducing dedicated storage devices. However, this heterogeneous architecture has high maintenance cost and might reduce the performance of virtual machines. In homogeneous IaaS cloud platform, servers in the platform would uniformly provide computing resources and storage resources, which effectively solve the above problems, although corresponding mechanisms need to be introduced to improve data availability. Efficient storage resource availability management is one of the key methods to improve data availability. As mechanical hard disk is the main way to realize data storage in IaaS cloud platform at present, timely and accurate prediction of mechanical hard disk failure and active data backup and migration before mechanical hard disk failure would effectively improve the data availability of IaaS cloud platform. In this paper, we propose an improved algorithm for early warning of mechanical hard disk failures. We first use the Relief feature selection algorithm to perform parameter selection. Then, we use the zero-sum game idea of Generative Adversarial Networks (GAN) to generate fewer category samples to achieve a balance of sample data. Finally, an improved Long Short-Term Memory (LSTM) model called Convolution-LSTM (C-LSTM) is used to complete accurate detection of hard disk failures and achieve fault warning. We evaluate several models using precision, recall, and Area Under Curve (AUC) value, and extensive experiments show that our proposed algorithm outperforms other algorithms for mechanical hard disk warning.

Acute anterior myocardial infarction complicated by a large ventricular septal defect

Post-Infarction Ventricular Septal Defect (PIVSD) are a rare complication of Acute Myocardial Infarction (AMI). According to clinical guidelines, surgical repair of a PIVSD is the recommended acute-stage course of treatment. Nevertheless, thoracotomy is not always clinically suggested for patients with unstable hemodynamics and otherwise at high risk. Currently, percutaneous interventional closure of a PIVSD represents an alternative therapy, and an attractive option for particular patients [1,2]. Here we report a 67-year-old man was transferred to Shenzhen Sun yat-sen Cardiovascular Hospital to evaluate a PIVSD and undergo repair. Echocardiography confirmed a large Ventricular Septal Defect (VSD) and significant left-to-right shunt (Figure 1a). Few reports of the closure of a PIVSD at an acute/subacute stage have been previously published. An interventional closure treatment (Amplatzer Septal Occluder device) was successfully performed after bridging to a subacute stage through use of mechanical circulatory backup (Figure 1b).

The Structure Design and Optimization of Electromagnetic-Mechanical Wedge Brake System

The electromagnetic-mechanical wedge brake system (EMWB) is a new structure designed for brake-by-wire system. This structure is composed of a DC motor, an electromagnet device, two wedges, two friction plates, a rotating rod and a brake disk. The presented EMWB system contains two brake actuators such as electromagnetic brake and motor brake. The EMWB system provides a mechanical backup brake model driven by the DC motor when the electromagnetic brake fails. In the braking relief phase, the maximum torque of the DC motor should meet the requirement of separating the friction plates from the brake disk, so the brake performance of EMWB system is simulated with Matlab/Simulink and optimized under the multi-objective constraints, and the simulation results demonstrate that the mechanical backup brake model can meet the brake requirements both for the front axle and the rear axle. Through the multi-objective optimization, the EMWB system can reach an acceptable brake performance and the DC motor can meet the requirement of relieving braking.

TCTAP C-144 Successful Percutaneous Coronary Intervention with Mechanical Back-up Support in a Patient with Eisenmenger’s Syndrome

TCTAP C-144 Successful Percutaneous Coronary Intervention with Mechanical Back-up Support in a Patient with Eisenmenger’s Syndrome

Arthroscopic Transtibial Tunnel Posterior Cruciate Ligament Reconstruction

The goals leading to successful posterior cruciate ligament (PCL) reconstruction surgery include identification and treatment of associated pathology such as posterolateral instability, posteromedial instability, and lower extremity malalignment. The use of strong graft material, properly placed tunnels to as closely as possible approximate the posterior cruciate ligament insertion sites, and the minimization of graft bending also enhance the probability of the PCL reconstruction success. In addition, mechanical graft tensioning, primary and backup PCL graft fixation, and the appropriate postoperative rehabilitation program are also necessary ingredients for PCL reconstruction success. Both single- and double-bundle PCL reconstruction surgical techniques are successful when evaluated with stress radiography, KT-1000 arthrometer measurements, and knee ligament rating scales. Indications for double-bundle PCL reconstruction as of this writing include severe hyperextension of the knee and revision PCL reconstruction. About 2–18-year postsurgical results in combined PCL, ACL, and medial- and lateral-side knee injuries (global laxity) revealed very successful PCL reconstruction using the arthroscopic transtibial tunnel surgical technique. The purpose of this chapter is to describe the arthroscopic transtibial tunnel PCL reconstruction surgical technique and present results with this surgical procedure.

New Brake By Wire Concept with Mechanical Backup

New Brake By Wire Concept with Mechanical Backup

Automobile Brake-by-Wire Control System Design and Analysis

The automobile brake-by-wire (BBW) system, which is also called the electromechanical brake system, has become a promising vehicle braking control scheme that enables many new driver interfaces and enhanced performances without a mechanical or hydraulic backup. In this paper, we survey BBW control systems with focuses on fault tolerance design and vehicle braking control schemes. At first, the system architecture of BBW systems is described. Fault tolerance design is then discussed to meet the high requirements of reliability and safety of BBW systems. A widely used braking model and several braking control schemes are investigated. Although previous work focused on antilock and antislip braking controls on a single wheel basis, we present a whole-vehicle control scheme to enhance vehicle stability and safety. Simulations based on the whole-vehicle braking model validate a proposed fuzzy logic control scheme in the lateral and yaw stability controls of vehicles.

Posterior Cruciate Ligament and Posterolateral Corner Reconstruction

The keys to successful posterior cruciate ligament reconstruction are to identify and treat all pathology, use strong graft material, accurately place tunnels in anatomic insertion sites, minimize graft bending, use a mechanical graft-tensioning device, use primary and backup graft fixation, and employ the appropriate postoperative rehabilitation program. Adherence to these technical points results in successful single and double bundle arthroscopic transtibial tunnel posterior cruciate ligament reconstruction documented with stress radiography, arthrometer, knee ligament rating scales, and patient satisfaction measurements.

High-Strength Nb<sub>3</sub>Sn Wire Development for Compact Superconducting Magnets

A superconducting magnet with a magnetic energy of E = B2/2μo [J/m3] has to overcome a magnetic force of P = B2/2μo [Pa] in the same expression. This means that a high-field 20 T superconducting magnet produces an electromagnetic force of 160 MPa. In order to stand such a large force, Nb3Sn superconducting wires are usually reinforced by the hard-copper housing as an external reinforcement method or the stainless steel winding as a mechanical backup of an outermost Nb3Sn coil. If we focus on a compact superconducting magnet like a cryocooled superconducting magnet, a high-strength superconducting wire with a small diameter size of 1- 2 mm is required. The High-Field Laboratory for Superconducting Materials, IMR, Tohoku University has developed Nb3Sn wires internally reinforced with CuNb or CuNbTi composite. These high-strength Nb3Sn wires were successfully employed to construct the unique compact cryocooled 28 T hybrid magnet and the cryocooled 18 T high-temperature superconducting magnet. In addition, we found that the prebending effect for high-strength Nb3Sn wires outstandingly improves the Tc, Bc2 and Ic properties. As a next step, we intend to develop new Nb3Sn strand cables with the strong mechanical property of 500 MPa, applying the prebending effect for a future 22 T-φ400 mm room temperature bore superconducting magnet of a 50 T-class hybrid magnet.

Adaptive mechanical backup ventilation for preterm infants on respiratory assist modes – a pilot study

Mechanical respiratory-assist modes, such as assist/control, low-rate intermittent mandatory ventilation, continuous positive airway pressure, or proportional assist ventilation (PAV), require a continuous respiratory effort. Because of the frequent occurrence of periodic breathing and/or apnea, mechanical backup ventilation must be initiated during episodes of reduced or absent respiratory drive to maintain gas exchange. The common approach to this problem is a regular conventional mechanical ventilation, which is initiated and withdrawn in an "on/off" function. To develop and evaluate a mechanical backup ventilation mode that is adaptive to the rapidly changing breathing pattern of preterm infants. Prospective randomized clinical crossover trial. Neonatal intensive care unit at the University of Munich, Germany. Preterm infants undergoing PAV. The infants were ventilated with PAV using a newly developed adaptive backup support, with and without pulse-oximetry-guided operation (SpO(2)-sensitive backup). Each infant was ventilated with both modes of backup support on 2 consecutive days, with the sequence randomized. The analysis on 11 preterm infants showed a statistically significant and clinically relevant reduction of the incidence (33%) and duration of oxygen desaturations (52%) when SpO(2)-sensitive adaptive backup support was used. SpO(2)-sensitive adaptive backup proved safe and effective in reducing the incidence and duration of oxygen desaturation in this short-term trial. This technology is potentially applicable to other assisted modalities of ventilation, such as noninvasive nasal ventilation.

Rotor drop and following thermal growth simulations using detailed auxiliary bearing and damper models

Catcher bearings (CBs) or auxiliary bearings provide mechanical backup protection in the events of magnetic bearing failure. This paper presents numerical analysis for a rotor drop on CBs and following thermal growths due to their mechanical rub using detailed CB and damper models. The detailed CB model is determined based on its material, geometry, speed and preload using the nonlinear Hertzian load–deflection formula, and the thermal growths of bearing components during the rotor drop are estimated using a 1D thermal model. A finite-element squeeze film damper provides the pressure profile of an annular oil film and the resulting viscous damping force. Numerical simulations of an energy storage flywheel with magnetic suspensions failed reveal that an optimal CB design using the detailed simulation models stabilizes the rotor drop dynamics and lowers the thermal growths while preventing the high-speed backward whirl. Furthermore, CB design guides based on the simulation results are presented.

Quantitative reliability analysis of different design alternatives for steer-by-wire system

For a fault-tolerant SBW (Steer-By-Wire) system, two structural designs with and without a backup mechanical coupling are proposed and assessed by a unified approach from a reliability point of view. An operation procedure to cope with partial system degradations prior to a complete loss of steering is presented for each design. The procedure can be represented by a transition diagram that, in turn, is converted into a layered Markov state transition diagram by introduction of augmented states. Reliabilities of the two designs are quantitatively compared by numerical integration of the Markov diagrams based on realistic failure rate data; system degradation probabilities are obtained as well as the complete steering loss probability. A power source is identified as a key component for the SBW to function without a mechanical backup.

Software Architecture of Drive-by-Wire Computer Systems

Computer systems applied to drive-by-wire vehicles without mechanical backup have to meet high demands for reliability. In this article a software architecture designed for these systems is introduced. The so-called system management integrates the components of a fault-tolerant control system (FTCS) with the software operating the redundant hardware structure. Firstly the paper gives an overview of the system management. To offer insights into its realisation the second part concentrates on the fault compensation unit of the FTCS. It applies data fusion techniques using the redundant input information of the drive-by-wire system to compensate signal failures.

Quantification of Reliability of Fault-Tolerant Steer-By-Wire System

A structural design was proposed in our previous study for a fault tolerant steer-by-wire (SBW) system consisting of a principal SBW, a standby SBW and a mechanical backup possibly with a power assist feature. The authors used fault trees, minimal cut sets, and minimal path sets to derive an operation procedure. The present paper converts this operation procedure into a Markov transition diagram where each state represents either a normal SBW, or a partially degraded or a completely failed SBW. The system reliability is quantified in terms of the state probabilities calculated from a numerical integration of the Markov diagram specified by component failure rates. It turns out that the SBW design demonstrates a considerably high reliability through the introduction of mechanical backup. The power assist, however, is rarely expected for the mechanical backup mode. This mode can be reduced by ECU reliability improvement.

The Iron Bird for the Fairchild-Dornier 728

A full size representative system integration test rig (Iron Bird) for the Fairchild-Dornier 728 regional jet has been designed and built. The 728 is a full fly-by-wire aircraft without mechanical back-up and is the benchmark for system integration in its class. The primary focus of Iron Bird testing is on flight controls, landing gear and hydraulics; other aircraft systems are installed for support. To reproduce in-flight aerodynamic loads, a hydraulically powered computer-controlled loading system is employed. The rig is not only used to minimize the development risk by testing fully integrated systems well in advance of the first test aircraft, as in previous programs, but also to unload ground and flight testing to the greatest extent possible as well as to conduct certification testing. A description of the Iron Bird structure and the aircraft systems' integration into the rig is given. An overview is provided of the rig's mechanical and electrical design as well as of its control and data acquisition system. The Iron Bird's capability to run in a closed loop configuration with the Engineering Simulator is highlighted. The main test targets are pointed out and results to date are presented. An outlook with respect to possible future testing and the extension of the capabilities of the Iron Bird facility is provided.

Fault-tolerant drive-by-wire systems

The article begins with a review of electronic driver assisting systems such as ABS, traction control, electronic stability control, and brake assistant. We then review drive-by-wire systems with and without mechanical backup. Drive-by-wire systems consist of an operating unit with an electrical output, haptic feedback to the driver, bus systems, microcomputers, power electronics, and electrical actuators. For their design safety, integrity methods such as reliability, fault tree and hazard analysis, and risk classification are required. Different fault-tolerance principles with various forms of redundancy are considered, resulting in fail-operational, fail-silent, and fail-safe systems. Fault-detection methods are discussed for use in low-cost components, followed by a review of principles for fault-tolerant design of sensors, actuators, and communication. We evaluate these methods and principles and show how they can be applied to low-cost automotive components and drive-by-wire systems. A brake-by-wire system with electronic pedal and electric brakes is then considered in more detail, showing the design of the components and the overall architecture. Finally, we present conclusions and an outlook for further development of drive-by-wire systems.

Computers Take Flight: A History of NASA's Pioneering Digital Fly-by-Wire Project

An overview of the NASA F-8 Fly-by Wire project is presented. The project made two significant contributions to the new technology: (1) a solid design base of techniques that work and those that do not, and (2) credible evidence of good flying qualities and the ability of such a system to tolerate real faults and to continue operation without degradation. In 1972 the F-8C aircraft used in the program became he first digital fly-by-wire aircraft to operate without a mechanical backup system.

Fault-Tolerant Drive-by-Wire Systems – Concepts and Realizations –

The development of automotive systems shows an increasing integration of electronic sensors, microcomputers and actuators for single components, engine, drive-chain, suspensions and brakes. After considering electronic driver assisting systems such as ABS, TCS, ASR, ESP, BA the developments towards drive-by-wire systems with and without mechanical or hydraulic backup are considered. Drive-by-wire systems consist of an operating unit (steering wheel, braking pedal) with an electrical output, a haptic feedback to the driver, bus systems, microcomputers, power electronics, and electrical actuators. For their design safety integrity methods like reliability, fault tree, hazard analysis and risk classification are required. Different fault tolerance principles with various forms of redundancy are considered resulting in fail-operational, fail-silent and fail-safe systems. Fault-detection methods are discussed for use in low-cost components. This is followed by some principles for fault-tolerant design of sensors, actuators and communication.A brake-by-wire system with electronic pedal and electrical brakes is then considered in more detail showing the design of the components and the overall architecture. An outlook then shows the further development of drive-by-wire systems.

Characteristics of the Aerodynamic Brake of the Vehicle on the Yamanashi Maglev Test Line.

The Yamanashi Maglev system has two types of main braking systems: regenerative braking system (primary brake using electrodynamic power) and on-board mechanical braking system (backup brake). The mechanical backup braking system is installed on vehicles. It is used to safely and accurately stop the vehicle in case the electrical braking system has failed. On the Yamanashi Maglev Test Line, an aerodynamic braking system is used as an element of the mechanical backup braking system. In the aerodynamic braking system, braking force is obtained by aerodynamic drag which is generated by unfolded brake panels. The aerodynamic brake is very effective in high speed operation, because the aerodynamic drag is proportional to the square of vehicle speed. This paper reports the aerodynamic brake system and results of running tests on the Yamanashi Maglev test line.

Electromechanical Ski Release Binding With Mechanical Backup

To better protect Alpine skiers against injuries to both the lower leg and the knee, the objective of this work was to design a binding which: (1) maintained a consistent release level in twist in the presence of combined loads; (2) released the heelpiece based on the anterior/posterior (A/P) bending moment transmitted by the leg; and (3) modulated the release level in twist depending on the degree of contraction in muscles crossing the knee. To fulfill the objective, a conventional ski binding was modified. Modifications included integrating dynamometers into the toepiece, anti-friction device (AFD), and heelpiece. The toepiece sensor indicates the twisting moment while the AFD and heelpiece sensors indicate the anterior bending moment transmitted by the leg. To gain electronic control of binding release, a solenoid actuated mechanism was added which translated the heelpiece rearward along the ski to decouple the boot from the binding. Otherwise, the binding allowed normal mechanical function. Prototype testing confirmed the ability of the dynamometers to accurately measure desired loads in the presence of extraneous loads and the reliability of the solenoid actuated mechanism in releasing the hoot under loads typical of skiing. Thus, this work demonstrated the feasibility of hybrid electromechanical/mechanical releasable bindings. Such a demonstration should encourage the development of designs for commercial use.