Development of Accommodation System for Faults in Thrusters of Underwater Robots

2021 ◽  
Vol 22 (5) ◽  
pp. 262-271
Author(s):  
V. F. Filaretov ◽  
A. V. Zuev ◽  
A. N. Zhirabok ◽  
A. A. Protsenko
Keyword(s):  
High Efficiency ◽  
Dynamic Properties ◽  
Variable Structure ◽  
Underwater Robots ◽  
Speed Sensor ◽  
Special Procedure ◽  
Additional Control ◽  
Third Stage ◽  
Reliability Of Operation ◽  
Types Of Faults

The article discusses a solution to the problem of increasing the reliability of operation of underwater robots through the use of accommodation systems that compensate for the consequences of faults that appear in the thrusters. The following types of faults were considered: 1) a fault in the rotation speed sensor of thruster, causing error in its readings; 2) overheating of the motor or short-circuiting of several turns of the winding of its armature circuit, causing a change in the value of electrical resistance; 3) the appearance of an unknown external torque effect on the engine shaft, including when winding plants on the propeller. A new method for constructing accommodation systems is proposed, which contains three stages. At the first, the detection of emerging faults is carried out using the bank of diagnostic observers. Each observer is synthesized according to a special procedure in such a way that the residual formed by it is sensitive to the appearance of various combinations of possible faults. This allows to detect each specific fault. At the second stage, the values of sensor errors and deviations of the parameters of the thruster from their nominal values are estimated by additional variable structure observers. At the third stage, additional control signals for robot’s thrusters are formed. They ensure the stabilization of dynamic properties and quality indicators of thrusters in the event of faults. The results of mathematical modeling are presented, which have confirmed the operability and high efficiency of the synthesized accommodation system.

Sliding Mode Control of a Hydraulic Industrial Robot

1999 ◽  
Vol 121 (2) ◽  
pp. 312-318 ◽  
Author(s):  
S. R. Habibi
Keyword(s):  
Performance Improvement ◽  
Sliding Mode ◽  
Industrial Robot ◽  
Variable Structure ◽  
Mathematical Function ◽  
Hydraulic Systems ◽  
Model Based ◽  
Additional Control ◽  
Feedback Compensation ◽  
Computed Torque

A general mathematical function for hydraulic actuators is reviewed in this paper. This model is used for the application of Computed Torque and Variable Structure controllers to a hydraulic industrial robot, the Workmaster, formerly manufactured by Thorn EMI Robotics. The model based controllers are examined to demonstrate the effectiveness of feedback and feedforward compensation in hydraulic systems. It is shown that a large performance improvement is obtained through feedforward and feedback compensation. A sliding mode component is added to model based compensation in order to improve the system’s performance by providing additional control action when there are modeling inaccuracies resulting from nonlinear friction effects.

A New Fuzzy Variable Structure Control of a Type of Nonlinear Multivariable System

2006 ◽  
Vol 315-316 ◽  
pp. 623-627
Author(s):  
P. Wei ◽  
Z.L. Wang ◽  
L.H. Qiu
Keyword(s):  
High Efficiency ◽  
Control Method ◽  
Fuzzy Variable ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Multivariable System ◽  
Robust Performance ◽  
Structure Control ◽  
System A ◽  
Novel Method

In order to improve the robust performance for a type of nonlinear multivariable system, a new fuzzy variable structure control method is introduced in detail, which combined the features of traditional variable structure control method with the advantages of the fuzzy control theory. The present work realized the linearization of the nonlinear multivariable system, and then the new fuzzy variable structure control method is applied to control the linearization system. The robust experiments were carried out on the novel method. The results indicated that the required robust performance could be achieved with high efficiency by utilizing the new method.

A Numerical Investigation of Aerodynamic Characteristics of a Deteriorated Gas Turbine

2017 ◽  
Author(s):  
Koichi Yonezawa ◽  
Genki Nakai ◽  
Kazuyasu Sugiyama ◽  
Katsuhiko Sugita ◽  
Shuichi Umezawa
Keyword(s):  
Numerical Investigation ◽  
Gas Turbine ◽  
Rotor Blade ◽  
High Efficiency ◽  
Aerodynamic Characteristics ◽  
Rotor Blades ◽  
Second Stage ◽  
The Third ◽  
Time Operation ◽  
Third Stage

In order to keep a high efficiency of a gas turbine, it is important to make a suitable maintenance. Gas turbine nozzle guide vanes (NGVs) and turbine rotor blades deteriorate through a long-time operation due to various causes such as a particle attachment, erosion, and a thermal stress. In the present study, a numerical investigation has been carried out to clarify the influence of the NGV and the rotor blade deterioration on aerodynamics in a 3-stage gas turbine. Geometries of the NGV and the rotor blade were measured from a real gas turbine using a 3-D scanner. The first stage NGVs and rotor blades usually deteriorate seriously and are usually replaced at certain intervals. Two kinds of the geometries of the NGV and the rotor blade of the first stage were obtained, which are the new ones before use and the used ones to be replaced. For the second stage and the third stage, the geometries before use were used in the computations. The numerical results show that the isentropic efficiency of the first stage increases and that of the second stage decrease due to the deterioration of the first stage. The efficiency of the third stage is not affected significantly. The mechanisms are discussed from the observation of the flow fields.

scholarly journals On the history of management of the third stage of labor in Kazan (to the 155th anniversary of the birth of Professor V.S. Gruzdev)

2021 ◽  
Vol 102 (2) ◽  
pp. 249-257
Author(s):  
L A Kozlov
Keyword(s):  
High Efficiency ◽  
Historical Study ◽  
Manual Removal ◽  
The Third ◽  
Obstetrics And Gynaecology ◽  
Third Stage Of Labor ◽  
Third Stage ◽  
Primary Literature ◽  
History Of ◽  
Speed Up

The article aims to show the experience of the Kazan Obstetrics and Gynaecology Clinic named after V.S. Gruzdev for replacing the obstetric operation manual removal of the placenta with other techniques to prevent serious postpartum complications. Research methods the historical study of primary literature sources. Manual removal of the placenta always associated with the risk of infection and developing puerperal sepsis. That is why obstetricians are constantly looking for a replacement for this operation. In 1895, even in the pre-Kazan period of work, professor Gruzdev successfully performed a method of inserting saline into the umbilical vessels to speed-up placental separation in the third stage of labor. While working in Kazan, on his proposal, doctor L.S. Sidorova (1936), and then Professor P.V. Manenkov (1942, 1948, 1955) and doctor M.V. Korotkova (1958) thoroughly studied and implemented the method of Budimilich in the work of the maternity ward of the clinic. This method involves replacing the saline solution with the crude alum solution. The second measure, preventing hemorrhage in the third stage of labor and avoiding manual removal of the placenta, was the successfully testing intravenous pituitrin (oxytocin) injection by Z.N. Yakubova, completed with the defense of her doctoral dissertation (1962). The high efficiency of these methods allowed us to recommend to them for widespread obstetric practice.

Enhanced Crawler with Multiple Search Techniques using Adaptive Link-Ranking and Pre-Query Processing

2016 ◽  
Vol 1 (1) ◽  
pp. 40-44
Author(s):  
Suchetadevi M. Gaikwad ◽  
Sanjay B. Thakare
Keyword(s):  
Query Processing ◽  
Associate Degree ◽  
High Efficiency ◽  
Keyword Search ◽  
Deep Web ◽  
Web Interfaces ◽  
Second Stage ◽  
Third Stage ◽  
Tree Data ◽  
Tree Data Structure

As deep web enlarges; there has been increased interest in methods which help efficiently trace deep-web interfaces. However, because of huge volume and varying nature of deep-web, achieving wide coverage and high efficiency is difficult issue. We proposed a three stage framework, an Enhanced Crawler, for efficiently gathering deep web interfaces. In first stage, enhanced crawler performs site based searching of center pages using automated search engines, avoiding visiting an oversized variety of pages and consuming time. In second stage, enhanced crawler achieves quick in site browsing by fetching most relevant links with associate degree of reconciling link ranking. For further enhancement, our system ranks and priorities websites and also uses a link tree data structure to achieve deep coverage. In third stage, our system provides pre-query processing mechanism so as to help users to write their search query easily by providing char by char keyword search with ranked indexing.

Two-Loop System with Reference Model for Control of Spatial Movement of Cargo Underwater Vehicle

2021 ◽  
Vol 22 (3) ◽  
pp. 134-144
Author(s):  
V. F. Filaretov ◽  
D. A. Yukhimets
Keyword(s):  
Control System ◽  
Control Systems ◽  
Dynamic Models ◽  
High Efficiency ◽  
Reference Model ◽  
Dynamic Properties ◽  
Autonomous Underwater Vehicles ◽  
Nonlinear Controller ◽  
Combined System ◽  
Spatial Trajectories

Currently, autonomous underwater vehicles (AUV) are increasingly used to perform tasks related to the maintenance of underwater communications and various underwater production complexes, as well as performing underwater technological operations. To effectively perform these operations, AUV must have high-quality control systems that will ensure their accurate movement both along long spatial trajectories formed during their movement to the objects of work, and when performing complex maneuvers near underwater infrastructure objects. At the same time, the main difficulty that arises in the process of synthesis of AUV control systems is the significant non-linearity of the dynamic models of these control objects, the presence of interactions between their degrees of freedom, as well as the uncertainty and variability of their parameters. In this paper, we propose a method for synthesizing the spatial motion control system of the AUV, which allows us to take into account these negative effects. This system contains two loops. The first loop includes a combined system containing a nonlinear controller to achieve the desired dynamic characteristics of the AUV, when its parameters are equal to the nominal values, and a controller with self-tuning according to the reference model, which provides compensation for an unknown or variable part of the parameters. In this case, the parameters of the controller with the reference model are selected to reduce the possible amplitude of the discontinuous signal for controlling the AUV velocity. The second loop is a non-linear position controller that allows to take into account the dynamic properties of the velocity control loop and the kinematic properties of the AUV. The advantage of the proposed control system in comparison with traditional ones based on PID controllers is a higher control accuracy when moving along complex spatial trajectories, regardless of changes in the AUV parameters. The simulation results confirmed the high efficiency of the synthesized two-loop control system.

Recovery braking of variable-structure electronic commutator for BLDC motor

2012 ◽  
Vol 61 (4) ◽  
pp. 579-596
Author(s):  
Tomasz Biskup
Keyword(s):  
Theoretical Analysis ◽  
Electric Vehicle ◽  
High Efficiency ◽  
Variable Structure ◽  
Bldc Motor ◽  
Simple Construction ◽  
Permanent Magnet Motors ◽  
High Torque ◽  
Electronic Commutator ◽  
Standard Range

Abstract Permanent magnet motors are more and more frequently used in various applications. In this group motors with a trapezoidal EMF deserve a special attention. They are characterized by a simple construction, high efficiency and high torque overload. A certain drawback of BLDC motors are difficulties with an operation at a speed above the nominal value. The article presents the results of investigations into the variablestructure electronic commutator designed for the drive of a small electric vehicle equipped with BLDC motors. Such a solution allows extending the standard range of the drive’s speed. The considerations contained in the article focus on the possibilities and effects of regeneration mode in the proposed topology of converter. A theoretical analysis has been presented as well as computer simulations carried out by means of Matlab- Simulink, which were then verified at a laboratory. The tests were finished with trials conducted using a small electric vehicle Elipsa.

Robust Variable Structure Control for Compound Active-Clamp Three-Phase PFC Converter with Soft Switch

2012 ◽  
Vol 433-440 ◽  
pp. 610-616
Author(s):  
Xin Guo ◽  
Hai Peng Ren
Keyword(s):  
High Efficiency ◽  
Control Method ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Simulation Method ◽  
Soft Switch ◽  
Structure Control ◽  
Three Phase ◽  
Parameter Perturbations ◽  
Good Potential

Compound active clamping three-phase Boost PFC converter with soft-switch has a good potential application because of its high power factor, high efficiency and simple structure. The mathematical model of this converter is analyzed. A variable structure control method with the robustness item is proposed for the control of this converter, in order to overcome the shortcoming of the existing method, when the converter parameters changes. The time-varying boundary layer is used to smooth the control discontinuity. Simulation is performed using PSIM and MATLAB hybrid simulation method. The results indicate that the proposed method possesses not only better transient and steady state performance under the nominal parameters, but also better robustness under the parameter perturbations, compared with the traditional PI control and the former variable structure control without the robustness item.

A New Method of Modeling Gear Faults

1982 ◽  
Vol 104 (2) ◽  
pp. 259-267 ◽  
Author(s):  
R. B. Randall
Keyword(s):  
Mathematical Models ◽  
Dynamic Properties ◽  
Vibration Signal ◽  
New Method ◽  
Detailed Knowledge ◽  
Signal Averaging ◽  
Monitoring And Diagnosis ◽  
Cepstrum Analysis ◽  
Alternative Approach ◽  
Types Of Faults

Detailed mathematical models of gear vibrations have appeared in recent years, but to utilize them requires a detailed knowledge of the gearbox components and their dynamic properties. This paper presents an alternative approach which is applicable to the monitoring and diagnosis of gearbox faults based on an analysis of changes in the vibration signal, showing how these can be related back to various classes of fault. Most emphasis is placed on the effects of the various types of faults on the spectrum, but the applicability of two other techniques, viz., synchronous signal averaging and cepstrum analysis, is also discussed comparatively, making use of practical examples.

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