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1
JIN, Bo. „Energy-regulation based variable speed hydraulic cylinder position control system“. Chinese Journal of Mechanical Engineering 44, Nr. 01 (2008): 25. http://dx.doi.org/10.3901/jme.2008.01.025.
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Patil, Navendu S., Jonathan B. Dingwell und Joseph P. Cusumano. „Task-level regulation enhances global stability of the simplest dynamic walker“. Journal of The Royal Society Interface 17, Nr. 168 (Juli 2020): 20200278. http://dx.doi.org/10.1098/rsif.2020.0278.
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Much remains unknown about how considerations such as stability and energy minimization shape the way humans walk. While active neuromotor control keeps humans upright, they also need to choose from multiple stepping regulation strategies to achieve one or more task goals, such as maintaining a desired speed or direction. Experiments on human treadmill walking motivate an important question: why do humans prefer one task-level regulation strategy over another—perhaps to enhance their ability to reject large disturbances? Here, we study the relationship between task-level regulation and global stability in a powered compass walker on a treadmill, with added step-to-step speed and position regulators. For treadmill walking, we find that speed regulation greatly enlarges and regularizes the unregulated walker’s stability region, i.e. its basin of attraction, much more than position regulation. Thus, our results suggest a possible explanation for the experimental finding that humans strongly prioritize regulating speed from one stride to the next, even as they walk economically on average. Furthermore, our work suggests a functional connection between task-level motor regulation and global stability—and, thus, perhaps even fall risk.
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Fan, Na, Zhi Quan Deng, Xiao Yuan Chen, Yu Yang Mao und Pei Lin Xu. „Speed Closed-Loop Control for Switched Reluctance Motor with Segmental Rotors Based on Angle Position Regulation“. Advanced Materials Research 433-440 (Januar 2012): 6789–94. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.6789.
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This paper describes the structure and the magnetic circuit of switched reluctance motor with segmental rotors (SSRM), and presents the control strategy of speed closed-loop by regulating the turn-on angle of the main switches in the power converter based on PI algorithm. The turn-off angle is optimized according to different speeds of the motor. The deviation of the rotor speed is the input control parameter of PI controller, and the turn-on angle is the output control parameter. The strategy of current chopping control is used for comparing with angle position control when rotor speed is high. Both the simulation and experimental results show the well transient, steady performance and robustness of SSRM based on the angle position controller.
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Xu, Qingsong. „Robust Impedance Control of a Compliant Microgripper for High-Speed Position/Force Regulation“. IEEE Transactions on Industrial Electronics 62, Nr. 2 (Februar 2015): 1201–9. http://dx.doi.org/10.1109/tie.2014.2352605.
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Zhao, Ji Yun, Hai Gang Ding und Liang Zhao. „Research on Electrohydraulic Servo Proportional Speed Regulation System for Anti-Explosion Hydraulic Hoisters“. Applied Mechanics and Materials 34-35 (Oktober 2010): 1205–10. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.1205.
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In terms of poor controllability of motor speed, the drum speed of the anti-explosion hydraulic hoister is fed back and controlled in closed loop. An electrohydraulic servoproportional speed regulation systems for anti-explosion hydraulic hoisters is proposed. Two control constructions are formed, the pump controlled motor system with/without position loop (PCMWP, PCMP, resp.) according to whether the displacement of pump is controlled in closed loop or not. Experiments of two control constructions are made under overflow load and weight load. Experimental results indicate that the presented system can simulate the process of anti-explosion hydraulic hoisters, and closed control loop could promote the control performance of hoister. Compared to the PCMP, the PCMWP is characterized by more stability with better speed follow and better robustness. At the same time, the cage instantaneous sliding at start-up and the pressure shock while braking are avoided effectively relying on the cooperation between the driving system and brake system, which ensure the security for hydraulic hoisters; the method of position correction by using travel switches at the end greatly enhances the precision of parking position.
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Lin, Yizhu, Gemma E. May, Hunter Kready, Lauren Nazzaro, Mao Mao, Pieter Spealman, Yehuda Creeger und C. Joel McManus. „Impacts of uORF codon identity and position on translation regulation“. Nucleic Acids Research 47, Nr. 17 (08.08.2019): 9358–67. http://dx.doi.org/10.1093/nar/gkz681.
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Abstract Translation regulation plays an important role in eukaryotic gene expression. Upstream open reading frames (uORFs) are potent regulatory elements located in 5′ mRNA transcript leaders. Translation of uORFs usually inhibit the translation of downstream main open reading frames, but some enhance expression. While a minority of uORFs encode conserved functional peptides, the coding regions of most uORFs are not conserved. Thus, the importance of uORF coding sequences on their regulatory functions remains largely unknown. We investigated the impact of an uORF coding region on gene regulation by assaying the functions of thousands of variants in the yeast YAP1 uORF. Varying uORF codons resulted in a wide range of functions, including repressing and enhancing expression of the downstream ORF. The presence of rare codons resulted in the most inhibitory YAP1 uORF variants. Inhibitory functions of such uORFs were abrogated by overexpression of complementary tRNA. Finally, regression analysis of our results indicated that both codon identity and position impact uORF function. Our results support a model in which a uORF coding sequence impacts its regulatory functions by altering the speed of uORF translation.
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Park, Gwangmin, Gyeongil Kim und Bon-Gwan Gu. „Sensorless PMSM Drive Inductance Estimation Based on a Data-Driven Approach“. Electronics 10, Nr. 7 (26.03.2021): 791. http://dx.doi.org/10.3390/electronics10070791.
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In the permanent magnet synchronous motor (PMSM) sensorless drive method, motor inductance is a decisive parameter for rotor position estimation. Due to core magnetic saturation, the motor current easily invokes inductance variation and degrades rotor position estimation accuracy. For a constant load torque, saturated inductance and inductance error in the sensorless drive method are constant. Inductance error results in constant rotor position estimation error and minor degradations, such as less optimal torque current, but no speed estimation error. For a periodic load torque, the inductance parameter error periodically fluctuates and, as a result, the position estimation error and speed error also periodically fluctuate. Periodic speed error makes speed regulation and load torque compensation especially difficult. This paper presents an inductance parameter estimator based on polynomial neural network (PNN) machine learning for PMSM sensorless drive with a period load torque compensator. By applying an inductance estimator, we also proposed a magnetic saturation compensation method to minimize periodic speed fluctuation. Simulation and experiments were conducted to validate the proposed method by confirming improved position and speed estimation accuracy and reduced system vibration against periodic load torque.
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Jiang, Wei Hua, Yuan Cheng Fan und Zheng Liu. „Double Position Loop Design of AC Servo Drive System“. Applied Mechanics and Materials 529 (Juni 2014): 486–90. http://dx.doi.org/10.4028/www.scientific.net/amm.529.486.
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The loop controller of double position fully closed makes the AC servo drive system acquire a very high position accuracy and speed following which is hard to be achieved for time-varying parameters, load disturbance, AC motors and severely nonlinear controlled objects. For the system, the dynamic nature can be ensured by the inner position loop adopting PI regulation of half closed loop structure, while the stability and the immunity can be achieved by closed loop structures with the rings outside adopting dual-mode fuzzy control. This article analyzes the cause of positioning errors for servo motor and semi-closed loop structure. The article also explains how to design a two position closed-loop servo system based on fuzzy control by adopting the AC servo motor drive, the motor shaft back-end incremental photoelectric encoder to form the inner position loop and using the motion control card, the inner ring of servo system and the work platform of grating ruler to make up the outer position loop. Based on double position loop composed of three-dimensional laser processing gear, the accuracy of the three-axis linkage workbench position control and the speed following can be ensured, thus meeting the requirement of the laser subsurface engraving machine for high speed and high precision motion.
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Huang, Shouren, Niklas Bergström, Yuji Yamakawa, Taku Senoo und Masatoshi Ishikawa. „Applying High-Speed Vision Sensing to an Industrial Robot for High-Performance Position Regulation under Uncertainties“. Sensors 16, Nr. 8 (29.07.2016): 1195. http://dx.doi.org/10.3390/s16081195.
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Qin, Ya Jie. „Numerical Investigation of Pneumatic Regulating on Low-Pressure Guide Vane“. Applied Mechanics and Materials 733 (Februar 2015): 554–57. http://dx.doi.org/10.4028/www.scientific.net/amm.733.554.
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In order to reduce the turbine flow, injecting an airstream into the mainstream of the low-pressure turbine from the casing. A CFD analysis has been carried out to study the impact of jet parameters (jet position, Angle, flow rate and velocity) to the turbine flow. The calculation results show that when the low-speed region caused by the jet flow locates at the throat the flow regulating effect is the most obvious. In additional, when the jet is against the main stream or with a big flow rate, the turbine flow regulation is better, but the loss efficiency of the turbine will be significantly increased. The jet Mach number has little influence on the effect of flow regulation.
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Liu, Xue Peng, und Dong Mei Zhao. „The Study on Motor Speed Controller“. Applied Mechanics and Materials 299 (Februar 2013): 89–92. http://dx.doi.org/10.4028/www.scientific.net/amm.299.89.
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The speed regulating motor controller is designed. On the basis of the controller the position detection, the control strategy and the main power circuit application are discussed. The related hardware debugging is completed and tested.
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Stol, Karl, und Mark Balas. „Full-State Feedback Control of a Variable-Speed Wind Turbine: A Comparison of Periodic and Constant Gains“. Journal of Solar Energy Engineering 123, Nr. 4 (01.07.2001): 319–26. http://dx.doi.org/10.1115/1.1412237.
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An investigation of the performance of a model-based periodic gain controller is presented for a two-bladed, variable-speed, horizontal-axis wind turbine. Performance is based on speed regulation using full-span collective blade pitch. The turbine is modeled with five degrees-of-freedom; tower fore-aft bending, nacelle yaw, rotor position, and flapwise bending of each blade. An attempt is made to quantify what model degrees-of-freedom make the system most periodic, using Floquet modal properties. This justifies the inclusion of yaw motion in the model. Optimal control ideas are adopted in the design of both periodic and constant gain full-state feedback controllers, based on a linearized periodic model. Upon comparison, no significant difference in performance is observed between the two types of control in speed regulation.
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Zhu, Jian Feng, Peng Xiang Hua, Jun Bang Liu, Xin Wang und Di Min Wu. „Research on Speed Control Problem of Industrial Sewing Machine System“. Applied Mechanics and Materials 602-605 (August 2014): 1117–21. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.1117.
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This paper presents a new method of braking control related to the brushless DC Motor control industrial sewing machine system by analyzing the braking method of brushless DC Motor and the characteristics of control method concerning industrial sewing machines system. With the RENESAS SH7125 MCU as the core controlling, this paper analyzes from the both aspects of speed regulation and braking control, adopts oscillating circuit frequency input method for frequency control, reversing locking brake by detecting needle position signal. Practice proves that the method has achieved good effect, met the control requirements of the industrial sewing machine system.
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Radzevicius, Lionginas, und Edvardas Matkevicius. „The Operation of the Linear Induction Motor by Changing the Position of the Inductors between each other“. Solid State Phenomena 144 (September 2008): 169–74. http://dx.doi.org/10.4028/www.scientific.net/ssp.144.169.
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The most important scientific theoretical research works of the linear induction motor (LIM) are made having in mind double – sided symmetric model with the uniform secondary element. Its operation is investigated by already well-known methods used for the rotor asynchronous machines and as a rule with the opposite value of the magnetic poles of the inductors (NS). Authors give the results of the research only of LIM (the scientific aspect of the problem is not well studied yet, it is little known about the ways of the speed and development regulation of the LIM force, by changing the location of the magnetic poles of the inductors (the inductors position between each other) from opposite (NS) to the same (NN) magnetic poles value which is the change of the phase of the inductor current from α = 0 till α = π. By theoretical methods were studied only the LIM features and possibilities their natural speed and the way of the force regulation, which could be used in the mechatronics systems.
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Paula, Greg. „Taking Sensors Out of Motors“. Mechanical Engineering 120, Nr. 01 (01.01.1998): 74–75. http://dx.doi.org/10.1115/1.1998-jan-6.
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This article discusses that advanced signal processors are replacing the feedback sensors that had been required for motor control in applications ranging from disk drives to appliance motors. The traditional method of closed-loop motor control has been to use one or more sensors to provide feedback. A growing number of applications, however, are now eliminating the sensor through one of several methods, such as back electromotive force (EMF) or inductance measurement. Sensorless motors are best suited for applications where speed control is needed, but precise position control is not critical. Sensorless motors are proving to be most appropriate for applications where the position of the rotor does not have to be pinpointed with great accuracy and all that is needed is speed and torque control. Prime candidates for sensorless motors are applications where open-loop scalar control had been used but better speed regulation and more torque at low speed are needed.
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Su, Rui, Xiaoming Rui, Xin Wu und Qidong Yin. „The design and analysis of wind turbine based on differential speed regulation“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, Nr. 2 (04.05.2015): 221–29. http://dx.doi.org/10.1177/0954406215586008.
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Aiming problems arising from the wind turbine with the frequency converter, this paper proposes a design for wind turbine based on differential speed regulation. The dynamic characteristics and parameter determination method of the structural components including differential gear train and speed regulating motor (SRM) were studied and the dynamic characteristic expression were obtained. The critical conditions about input power or output power for ring gear driven by SRM were researched. The way to determine the optimal structure parameters of SRM was put forward. The minimum peak power of SRM was regarded as the objective function while the transmission ratios of three gear sets which were placed in the different positions of overall structure scheme was optimized. A SIMULINK model of 1.5 MW wind turbine based on differential speed regulation was built and ran. The rotational speed, torque and power of the wind rotor, the SRM and the synchronous generator were obtained respectively. The simulation results can verify effectiveness of the theoretical analysis and parameter configuration.
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Liu, Wei, Yunhua Li und Dong Li. „A coordinated control law for inlet/outlet independent regulation of electro-hydraulic speed control system under sustained negative load“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, Nr. 9 (16.01.2020): 1689–705. http://dx.doi.org/10.1177/0954406219899691.
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Negative load operation is an inevitable operating condition for a completed task cycle of electro-hydraulic speed control system. In this working condition, to coordinate both tracking control and speed smooth regulation is necessary for avoiding stall. In this paper, a nonlinear coordinated control law aiming at independent regulation of inlet/outlet oil of valve-controlled electro-hydraulic speed system under sustained negative load is proposed. The overall control system can be divided into position tracking control subsystem and speed smooth control subsystem according to the function of the system operation. First, the coordinated control strategy is designed according to the requirements of speed tracking and speed smoothing. Then, for the coupling control problem existed in the system, a novel control law based on objective acceleration planning and expected back-pressure planning is presented. Furthermore, specified on the problem of uncertain random disturbance in practical applications, the extended state observer is designed, extending the summation of uncertain stochastic disturbance under sustained negative load into a new state variable. Finally, addressing the coordinated control strategy with expected back-pressure planning, we designed nonlinear decoupling control laws by using backstepping sliding mode robust control and backstepping sliding mode control based on extended state observer, respectively. The results of simulation and experiment show that the proposed nonlinear coordinated control strategy can provide the excellent coordination and robust performance for tracking control and speed smooth regulation.
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Liu, Guan Da, Bo Mo, De Zhi Zhou und Shu Cen Du. „High-Speed Brushless DC Motor Current-Loop Sampling System Design for Three-Axis Turntable“. Applied Mechanics and Materials 527 (Februar 2014): 252–58. http://dx.doi.org/10.4028/www.scientific.net/amm.527.252.
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Brushless DC motor (BLDCM) is adopted in the driving of a three-axis turntable. A high-speed current sampling system plays a vital role in intelligent control. This article firstly describes the working principle of a triple-closed-loop regulation system and emphatically dissects the characteristic of the current-loop among speed-loop and position-loop. Secondly, a signal acquisition-alignment circuit of three phases’ current and voltage is designed. Based on ADS8365, a scheme of high-speed current loop’s precise and synchronous sampling system is provided. Finally, experimental results have proved the validity and practicality of the scheme applied in the control of three-axis turntable.
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Shi, Yong, Lian Yu Zhang, Jun Sun und Hong Guang Zhang. „Research on the Speed of Diesel Engine Based on Improved BP Neural Network Controller“. Applied Mechanics and Materials 281 (Januar 2013): 105–11. http://dx.doi.org/10.4028/www.scientific.net/amm.281.105.
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Marine diesel engine is of characteristics of non-linear and time-invariant, so it is difficult to be controlled with traditional PID controller. An adaptive controller based on back-propagation (BP) neural networks was put forwarded for marine diesel engine speed control system, where two neural networks are proposed to control the position loop and speed loop. The adaptive controller was improved was improved via introducing relative error in target evaluation function of the BP neural network, and obtain sensitivity function of diesel engine output with respect to its input using a differential equation. The controller has self-learning and adaptive capacity. It can also optimize the PID controller parameters online. The controller was experimentally evaluated on rack position actuator of marine diesel engine simulated based on a diesel hardware-in-loop system of dSPACE. Finally, tests on a diesel engine demonstrated that the controller can satisfy the transient and steady demands of speed regulation system.
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Zhang, Ji, Qigang Gao und Hai Wang. „Discover Gene Specific Local Co-Regulations from Time-Course Gene Expression Data“. Scientific Programming 16, Nr. 1 (2008): 31–47. http://dx.doi.org/10.1155/2008/182058.
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Discovering gene co-regulatory relationships is one of most important research in DNA microarray data analysis. The problem of gene specific co-regulation discovery is to, for a particular gene of interest (called target gene), identify the condition subsets where strong gene co-regulations of the target gene are observed and its co-regulated genes in these condition subsets. The co-regulations are local in the sense that they occur in some subsets of full experimental conditions. The study on this problem can contribute to better understanding and characterizing the target gene during the biological activity involved. In this paper, we propose an innovative method for finding gene specific co-regulations using genetic algorithm (GA). A sliding window is used to delimit the allowed length of conditions in which gene co-regulations occur and anad hocGA, called the progressive GA, is performed in each window position to find those condition subsets having high fitness. It is called progressive because the initial population for the GA in a window position inherits the top-ranked individuals obtained in its preceding window position, enabling the GA to achieve a better accuracy than the non-progressive algorithm.kNN Lookup Table is utilized to substantially speed up fitness evaluation in the GA. Experimental results with a real-life gene expression data demonstrate the efficiency and effectiveness of our technique in discovering gene specific co-regulations.
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Shoby, Niba, Deepika Vasanthakumar und Anupama P K. „Speed Control Using Fuzzy Controller for a Four Switch Sensorless BLDC Motor“. Volume 5 - 2020, Issue 8 - August 5, Nr. 8 (16.09.2020): 1668–74. http://dx.doi.org/10.38124/ijisrt20aug689.
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- Brushless Direct Current (BLDC) motors are highly efficient motors with high reliability and a longer life span. The advent of sensor less technology has improved the performance and reliability of BLDC motor drives. This work is to analyze a drive system for BLDC motor with Four-Switch Three-Phase Inverter (FSTPI). Back Electromotive Force (EMF) Zero Crossing Detection (ZCD) method is used to estimate the rotor position. Speed control of motor is achieved by using Fuzzy Logic Controller (FLC) based closed loop control system. The Simulation was carried out using MATLAB software and motor the performance was analyzed with FLC for motor speed regulation.
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Hu, Liang Bin, Bi Wen Li, Sheng Li und Yao Bin Hu. „Development for CAD / CAM System of Modification Slotting Cutter’s Design and Manufacture for High-Speed and Heavy-Loading Gear“. Advanced Materials Research 591-593 (November 2012): 263–66. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.263.
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In view of the advantages of slotting modification processing and the difficulties in the design and manufacture of Modification Slotting Cutter, development for CAD / CAM system of modification slotting cutter’s design and manufacture for high-speed and heavy-loading gear has the following features:Firstly, the adaptive design of modification slotting cutter is implemented based on different modification target.Secondly,the precise design of modification slotting cutter is implemented by automatic regulating its section line position based on simulation results of the evaluation of the modification. Thirdly, the automatic regulation for fixture system and wire cutting process parameters of modification slotting cutter is implemented based on prediction model of slotting cutter’s pressure angle error, thereby reducing the design and manufacturing difficulty and to improve the precision as well as self-adaptability for modification slotting cutter.
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Jackowski, Jerzy, und Olga Michnikowska. „The influence of rear car seat position on the child’s load condition during collision“. Mechanik 90, Nr. 2 (06.02.2017): 144–47. http://dx.doi.org/10.17814/mechanik.2017.2.34.
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The paper presents the results of the crash test aimed at observe level of acceleration of the dummy representing a child at the age of 3 years, seated in the car seat with various angle position of the rear seat of car. The research was carried out during simulated frontal collision at a speed of about 15 km/h. Selected for the child seats II÷III (15÷36 kg) weight category according to Regulation No. 44 of UNECE. Presented results of stand tests are aimed at compare dependence effect inclination angle the car seat and method of fixing it on car seat on examples.
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Song, Hui Ying, Lei Chen, Xiao Qiang Li und Ping Tao Ni. „The Control of the Modified Meter of Flight Equipments“. Advanced Materials Research 756-759 (September 2013): 214–17. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.214.
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This article is to do a research for flight simulation modified meter, to design a basic control circuit of stepping-motor modified meter, to control the signal supplied by PIC MCU, and get to the result of clockwise and anti-clockwise rotation, speed regulation, reversion to zero position of index and other controls. The control request can be achieved as a real modified meter after the improvement under the foundation of the basic control circuit.
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Ivanov, Vladimir. „Dynamic Compensation of Parameters in Servo Drives“. Известия высших учебных заведений. Электромеханика 64, Nr. 3 (2021): 36–44. http://dx.doi.org/10.17213/0136-3360-2021-3-36-44.
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In this paper, we studied a servo drive with an unlimited increase in the gain coefficients of the speed con-tour. We demonstrated dynamic compensation of parameters associated with the formation of differential com-ponents based on the coverage of the real coordinates of the control object using static model. It was shown that dynamics of the transient processes is caused by real differentiating links determining the fast and slow components of the transient process. The static velocity error in this case did not depend on the ratio of large and small time constants, as in a single integrating system of subordinate regulation of parameters. Therefore, we considered that parametric disturbances and their compensation occur due to the external astatic circuit. We demonstrated an equivalent transition to the position contour, the speed structure and position generator, corresponding to the organization of the servo drive in the CNC systems. We investigated features of the phase discriminator during the operation of the position sensor in the phase difference mode and carried out model-ing of the servo drive structures and comparative analysis of two and three-circuit systems.
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Friedrich, Martin G., Ioannes Bougioukas, Peter Wenig, Steffen Vormfelde und Theodor Tirilomis. „New device for intraoperative blood suction avoiding turbulences“. BMJ Innovations 4, Nr. 2 (01.02.2018): 91–97. http://dx.doi.org/10.1136/bmjinnov-2017-000201.
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IntroductionBleeding during surgery is common. Increased bleeding may disturb procedure, induces haemodynamic instability and results in need for blood transfusion. Allogenic blood transfusions increase mortality and morbidity, especially risk of infections, pulmonary and renal complications, as well as thromboembolic events. Autotransfusion is in many cases a solution but forced suction may destroy or alter blood cells because of turbulences, shear forces and contact of the blood to extrinsic surfaces. The aim of the study was the analysis of turbulence profile and development of a new suction device reducing (or avoiding) turbulences.MethodsWe registered turbulences with a microphone placed in different positions within the blood suction during surgery and analysed the spectrum. Then, we modified the circuit adding signals from optical sensors and pressure transducer to avoid air mixing and tight suction. Finally, we created the algorithm for the suction circuit regulating individualised suction modes.ResultsWe developed a new suction system based on a roller pump. We used a piezo sensor and registered the acoustic signals. The optimal position for this element was into the suction handle. After filtering the signal and further processing, we used it for regulation of the roller pump. Additionally, an optical sensor minimises air mixing due to further regulation of motor speed. Finally, a negative pressure transducer gives in case of tight suction information to the circuit stopping motor speed and equalising pressure by opening a valve before suctions starts again. The algorithm allows various suction modes in an individualised manner for specific situations in operating field.ConclusionsWe developed a new blood suction device based on a roller pump. The system is turbulence-controlled and its algorithm allows several individualised suction modes. Additional features avoid tight suction and reduce air mixing.
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Высоцкий, В. Е., С. А. Конева, И. Ю. Марков und В. М. Цалоев. „Synthesis of a scalar ACS of the valve motor rotational speed for the icebreaker's ERM with a propulsion-steering complex "Azipod"“. MORSKIE INTELLEKTUAL`NYE TEHNOLOGII), Nr. 3(53) (27.08.2021): 207–14. http://dx.doi.org/10.37220/mit.2021.53.3.024.
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В статье рассматриваются основные тенденции развития систем судового автоматизированного электропривода с машинами переменного тока. В частности представлены варианты реализации электропривода с использованием частотно управляемых асинхронных двигателей и синхронных двигателей с электромагнитным возбуждением. Предлагается перспективная электромеханическая система на основе вентильного двигателя для ГЭУ ледокола с движительно-рулевым комплексом «Азипод». Целью работы является исключение структурной сложности и повышения функциональных возможностей электропривода за счет применения скалярной САУ частоты вращения вентильного двигателя вместо векторной для ГЭУ. Новизна заключается в использовании подхода и представления вентильного двигателя как объекта регулирования на основе аналогии с коллекторным двигателем постоянного тока при регулировании положения его оси токосъема. В соответствии с этим анализ информационных процессов, связанных с процессами электромеханического преобразования энергии, протекающими в синхронной машине с позиционно-зависимым частотным управлением, и синтез САУ электропривода по принципу подчиненного регулирования базируются на тех подходах, которые широко используются в регулируемых электроприводах постоянного тока, обладающих наилучшими динамическими свойствами. The article discusses the main trends in the development of marine automated electric drive systems with AC machines. In particular, variants of the implementation of an electric drive using frequency-controlled asynchronous motors and synchronous motors with electromagnetic excitation are presented. A promising electromechanical system based on a valve engine for the icebreaker's ERM with the propulsion-steering system Azipod is proposed. The aim of the work is to eliminate the structural complexity and to increase the functionality of the electric drive by using a scalar ACS of the valve motor rotational speed instead of a vector one for the ERM. The novelty lies in the use of the approach and representation of the valve motor as an object of regulation based on the analogy with the collector DC motor when regulating the position of its current collection axis. Thereby, the analysis of information processes related to the processes of electromechanical energy conversion occurring in a synchronous machine with position-dependent frequency control, and the synthesis of an ACS electric drive based on the principle of subordinate regulation are based on those approaches that are widely used in regulated DC electric drives possessing the best dynamic properties.
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Liu, Jianbin, Haibo Xie, Liang Hu, Huayong Yang und Xin Fu. „Flow force regulation of the main poppet in a large flow load control valve“. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 231, Nr. 8 (09.06.2017): 706–20. http://dx.doi.org/10.1177/0957650917714370.
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This paper presents the regulation methods of flow forces acting on the main poppet in a large flow load control valve. The negative flow forces working on the originally designed main poppet, which is as high as 10% of the control force, act as a big disturbance to the main poppet position control, resulting in poor lowering speed control performance of the load control valve or even instability of the main poppet. Firstly, by introducing a damping tail structure to the main poppet, the direction of the flow forces can be regulated to positive and best stability of the main poppet can be achieved with the calculated best parameter combination. Secondly, by introducing a damping tail with holes to the main poppet, the positive flow forces of all main poppet positions can be reduced to minimum, which results in minimum disturbance for the control of main poppet. Computational fluid dynamics calculations were conducted to analyze how the damping tail parameters affect the flow forces and obtain the best parameter combinations. A test rig was set up to validate the effect of above methods. Good agreement of the computational fluid dynamics calculations and experiment results indicates that the proposed methods can provide guidance for the flow force regulation of other valve poppets.
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Liang, Cunman, Fujun Wang, Yanling Tian, Xingyu Zhao und Dawei Zhang. „Development of a high speed and precision wire clamp with both position and force regulations“. Robotics and Computer-Integrated Manufacturing 44 (April 2017): 208–17. http://dx.doi.org/10.1016/j.rcim.2016.09.006.
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Hoai, Hung-Khong, Seng-Chi Chen und Hoang Than. „Realization of the Sensorless Permanent Magnet Synchronous Motor Drive Control System with an Intelligent Controller“. Electronics 9, Nr. 2 (21.02.2020): 365. http://dx.doi.org/10.3390/electronics9020365.
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This paper presents the sensorless control algorithm for a permanent magnet synchronous motor (PMSM) drive system with the estimator and the intelligent controller. The estimator is constructed on the novel sliding mode observer (SMO) in combination with a phase-locked loop (PLL) to estimate the position and speed of the rotor. The intelligent controller is a radial basis function neural network (RBFNN)-based self-tuning PID (Proportional-Integral-Derivative) controller, applied to the velocity control loop of the PMSM drive control system to adapt strongly to dynamic characteristics during the operation with an external load. The I-f startup strategy is adopted to accelerate the motor from standstill, then switches to the sensorless mode smoothly. The control algorithm program is based on MATLAB and can be executed in simulations and experiments. The control system performance is verified on an experimental platform with various speeds and the dynamic load, in which the specified I-f startup mode and sensorless mode, inspected by tracking response and speed regulation. The simulation and experimental results demonstrate that the proposed method has worked successfully. The motor control system has smooth switching, good tracking response, and robustness against disturbance.
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Shadrin, G. K., D. L. Alontseva, A. T. Kussaiyn-Murat und A. L. Krasavin. „Synthesis of the Robotic Tool Motion-Controlling Algorithm Using Method of Correction Dynamics and Pertubations Compensation“. Mekhatronika, Avtomatizatsiya, Upravlenie 20, Nr. 8 (08.08.2019): 472–81. http://dx.doi.org/10.17587/mau.20.472-481.
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The task of controlling the manipulation robot movement in one direction has been considered. Such task appears at cutting, welding, painting and other similar operations, when the robot instrument performs a program motion along the working surface and at the same time, it is necessary to keep a definite distance from this instrument to the surface automatically without excessive correction. A new algorithm of controlling the linear object of the second order of the general form has been obtained by dynamics and perturbations compensation method, which takes precedence over well-known decisions. The algorithm provides a zero static error of the system regulation and movement in acquisition of external effects within the accuracy of standard filters of the second order that is convenient for practical use. The first filter indicates movements of the system during the task performing; the second one provides perturbations compensation on state variables. A step-by-step procedure of the algorithm synthesis has been represented for the second order controlled object of the general form. Formulae for calculating regulator coefficients have been obtained. The obtained equations defining processes in a closed control system allow performing the analysis of the control quality and the dynamics of control changes depending on external influences. A method of equations identification of the robot motion in conditions when we know the maximum speed of its instrument movement and a dynamic error of the robot servosystem regulating has been developed. By this method, the robot equations are brought up to the Vyshnegradskiy’s form and then on the computer model a fundamental frequency and a decay factor can be easily chosen. The application of the obtained algorithm has been reviewed to create a system of automatic regulation of the robot instrument position. It has been clarified that defining free coefficients of these filters on position of filter fundamental frequency equation and a controlled object provides the given system operation speed at moderate amplitude of controlling actions. A mathematical modeling method has shown the advantages of regulation program quality, parametric and structural robustness of the obtained control system.
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Lozano, José Luís, Jordi Corbera und F. Xavier Martínez de Osés. „Design of a Remote Monitoring System for High Speed Craft“. Journal of Navigation 53, Nr. 3 (September 2000): 465–71. http://dx.doi.org/10.1017/s0373463300008924.
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At present, the whole shipping industry is concerned about safety of navigation. In particular, attention is focused on High Speed Craft. There has been a sharp increase in numbers of this kind of vessel, which primarily carries passengers but is also known to carry goods. Some units can reach speeds of over 45 knots with capacity for 900 passengers. These passengers have a basic right to life and their means of transport should obviously follow all safety codes, regulations and IMO resolutions. This paper describes the development of a monitoring system that could automatically transmit safety parameters and position from the ship to a management control centre. Digital and analogical alarms, ship condition readings and other safety-related parameters may be recorded and transmitted in near real- time using the latest communications and positioning technologies.
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Fee, Robert J., Jacqueline Montes und Veronica J. Hinton. „Executive Functioning in the Dystrophinopathies and the Relation to Underlying Mutation Position“. Journal of the International Neuropsychological Society 25, Nr. 2 (04.12.2018): 146–55. http://dx.doi.org/10.1017/s1355617718000942.
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AbstractObjectives: The aim of this study was to investigate executive skills in children with dystrophinopathy and to examine the association between executive functions and dystrophin gene mutation position. Methods: Fifty boys with dystrophinopathy (mean age, 11 years 0 months; ages range, 5 to 17 years) completed measures of intellectual functioning (IF), working memory and executive functioning [including Digit Span (working memory) and measures from the NIH Toolbox (selective attention/inhibitory control, set shifting, working memory, and processing speed)]. Parents completed the Behavior Rating Inventory of Executive Function (BRIEF). Mutation positions were categorized into three groups (upstream exon 30, 31–62, and downstream exon 63). Paired-samples t tests compared performance on executive measures to IF, and a one-way (three-group) multivariate analysis of covariance compared cognitive performance with mutation location controlling for motor functioning. Results: Mean performance on all executive measures was significantly lower than IF. Parents were also more likely to rate their child with dystrophinopathy as having clinically significant executive difficulties on the Shift, Emotional Control, and Behavior Regulation indices of the BRIEF. Mutation analyses resulted in small groups limiting power to detect subtle differences. Those with a downstream mutation position had significantly poorer performance on IF and Total Digit Span, but not on other measures of executive function including behavior. Conclusions: Individuals with dystrophinopathy have executive skill deficits, but they are not generally associated with more distal mutations. (JINS, 2019, 25, 146–155)
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Wang, Ang, Chenghua Shi, Chenyang Zhao, E. Deng, Weichao Yang und Hong He. „Response Characteristics of Cross Tunnel Lining under Dynamic Train Load“. Applied Sciences 10, Nr. 12 (26.06.2020): 4406. http://dx.doi.org/10.3390/app10124406.
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The crossing area is a vulnerable component of the interchange high-speed railway tunnel because of the high-static stress level and the long-term dynamic train load in the operation period. Although attention has been paid to this problem, the response characteristics of high-speed railway tunnel lining at the cross position under the dynamic train load may still need further research as very little investigation is available on this issue at present. In this paper, the initial stress state and dynamic response characteristics of tunnel lining were studied using the three-dimensional finite element method. Furthermore, the damage evolutionary characteristics of the tunnel inverted arch under dynamic and initial static loads were researched using a set of self-developed indoor fatigue test devices. The size of the test box is 400 × 300 × 250 mm (length × width × height). Numerical simulation results indicate that the displacement and stress levels of tunnel lining are very high at the cross position. The stress increment of tunnel lining due to the dynamic train load is more likely to induce a break in the tunnel lining at this position. The indoor fatigue tests reveal that the change of structural strain increment amplitude and strain ratio is obvious when the dynamic load stress level is higher. It is better for dynamic stress levels not to exceed 0.6 times of structural tensile strength to avoid the tunnel lining being damaged in the long-time service period. The initial static load has an influence on the tunnel inverted arch, and the static stress level should be lower than 0.65 times of structural tensile strength to ensure the tunnel has long-time serviceability. This paper provides a reference for the future design of new cross tunnels and the operation safety evaluation and disease regulation of existing high-speed railway tunnels.
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Zhou, Fan, Shengda Pan und Jingjing Jiang. „Verification of AIS Data by using Video Images taken by a UAV“. Journal of Navigation 72, Nr. 06 (08.05.2019): 1345–58. http://dx.doi.org/10.1017/s0373463319000262.
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Effective technical methods for verifying the authenticity and accuracy of Automatic Identification System (AIS) data, which are important for safe navigation and traffic regulation, are still lacking. In this study, we propose a new method to verify AIS data by using video images taken by an Unmanned Aerial Vehicle (UAV). An improved ViBe algorithm is used to extract the ship target image from the video images and the ship's spatial position is calculated using a monocular target-positioning algorithm. The positioning results are compared with the position, speed and course data of the same ship in AIS, and the authenticity and accuracy of the AIS data are verified. The results of the experiment conducted in the inland waterways of Huangpu River in Shanghai, China, show that AIS signals can be automatically checked and verified by a UAV in real time and can thus improve the supervision efficiency of maritime departments.
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Ruth, Deivamoney Josephine Selvarani, Kaliaperumal Dhanalakshmi und Seung-Bok Choi. „A Sensaptic ADAS Device Using Shape Memory Alloy Wires: Design and Control“. Materials 14, Nr. 13 (23.06.2021): 3494. http://dx.doi.org/10.3390/ma14133494.
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This paper presents an active accelerator pedal system based on an integrated sensor and actuator using shape memory alloy (SMA) for speed control and to create haptics in the accelerator pedal. A device named sensaptics is developed with a pair of bi-functional SMA wires instrumented in a synergistic configuration function as an active sensor for positioning the accelerator pedal (pedal position sensing) to control the vehicle speed through electronic throttle and as a variable impedance actuator to generate active force (haptic) feedback to the driver. The reaction force emanated from the pedal alerts the driver and takes appropriate control action by slowing down the vehicle, in harmony with the road’s condition. The design is developed as a proof-of-concept device and is tested and evaluated in a real-time common rail diesel system for rail pressure regulation and over speeding tests, and the responses and performances are found to be promising.
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Li, Lijiao, Ran Shi, Xiaohui Zhang, Jiyu Ma und Jun Zhang. „Design of Motion Controller for Satellite-Borne Data Transmission Antenna“. International Journal of Aerospace Engineering 2019 (24.10.2019): 1–11. http://dx.doi.org/10.1155/2019/6030761.
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In order to realize stable, reliable, and high-precision motion control of the satellite-borne data transmission antenna, a FPGA-based motion controller is designed and achieved. The controller receives commands through the RS-422 asynchronous transmission serial port and performs speed planning autonomously. The controller also performs closed-loop position control with the collected resolver angle and controls two antennas synchronously or independently in a subdivision driving method. The controller is firstly designed using the hardware description language VHDL, simulated in ModelSim software. Then, it is connected to the stepping motors through the LMD18200H bridge chip by using aerospace-grade FPGA, controlling the data transmission antennas to regulate the angle, go to zero-position, or stop rotation. The simulation and experiment results show that the design can control the antennas accurately and stably. The accuracy of angle regulation reaches 0.0085° under the condition of 64 subdivisions and 100 : 1 reduction ratio.
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Guo, Qi, Zhongming Zheng, Bo Wang, Xuepeng Pan, Shanren Liu, Zhennan Tian, Chao Chen und Yongsen Yu. „Femtosecond Laser Fabricated Apodized Fiber Bragg Gratings Based on Energy Regulation“. Photonics 8, Nr. 4 (07.04.2021): 110. http://dx.doi.org/10.3390/photonics8040110.
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In this paper, an energy regulation method based on the combination of a half-wave plate (HWP) and a polarization beam splitter (PBS) is proposed for the fabrication of apodized fiber gratings, which can effectively improve the side lobe suppression ratio of high-reflectivity fiber Bragg gratings (FBGs) fabricated by femtosecond laser. The apodized FBGs prepared by this method has good repeatability and flexibility. By inputting different types of apodization functions through the program, the rotation speed of the stepping motor can be adjusted synchronously, and then the position of the HWP can be accurately controlled so that the laser energy can be distributed as an apodization function along the axial direction of the fiber. By using the energy apodization method, the gratings with a reflectivity of 75% and a side lobe suppression ratio of 25 and 32 dB are fabricated in the fiber with a core diameter of 9 and 4.4 μm, respectively. The temperature and strain sensitivities of the energy-apodized fiber gratings with a core diameter of 4.4 μm are 10.36 pm/°C and 0.9 pm/με, respectively. The high-reflectivity gratings fabricated by this energy apodization method are expected to be used in high-power narrow-linewidth lasers and wavelength division multiplexing (WDM) systems.
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Wang, Qiang, Qian Wu und Xian Ke Zhang. „Study on Regulation of Rotation Speeds and Tangent Slip in Radial-Axial Ring Rolling Process“. Advanced Materials Research 189-193 (Februar 2011): 2680–83. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.2680.
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Radial-axial ring rolling is a process widely used to produce large precise seamless rings. The regulation of rotation speeds between main roll and axial rolls and tangential slip between main roll and ring influence greatly the rolling process. In this paper, an equation governing regulation of rotation speeds is derived. Influences to rotation speeds from conic angle and contact position are analyzed. Equation of relative tangential slip speeds in both inner and outer diameters are established, which are employed to creat a condition of non tangential slip in radial-axial ring rolling process.
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Jerkan, Dejan, und Darko Marčetić. „Advanced model of IM including rotor slot harmonics“. COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 34, Nr. 1 (05.01.2015): 261–78. http://dx.doi.org/10.1108/compel-03-2014-0051.
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Purpose – The purpose of this paper is to present a detailed advanced dynamical model of induction machine (IM) with unskewed rotor bars, including rotor slot harmonics. Design/methodology/approach – Procedure of IM modeling using results from finite element analysis (FEA). Series of magneto-static FEA simulations are used to obtain matrix of IM inductances as a function of rotor angular position and geometry. Each element in this matrix is represented by Fourier series (FS) and incorporated in proposed dynamical model. Using or neglecting various elements in FS of inductance matrix may be useful for determining which component of the series has dominant influence on harmonic content of stator currents, torque ripple or speed variation. The usefulness of application of presented model is verified comparing with time-stepping FEA simulations. Findings – Although the model is not suitable for usage in on-line regulation of IM drives, but the results of simulations may be used to thoroughly explain origins of higher order harmonics in stator currents of IM and help improve sensorless speed estimation algorithms and fault diagnostics. Originality/value – This paper shows an approach to the modeling of IM which includes effects of non-uniform air gap and non-sinusoidal distributions of magneto-motive forces. Inductance matrix elements are complex functions of rotor position, geometry and winding distributions and it gives an opportunity for detail analysis of IM behavior in numerous applications.
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Zedgenizov, Dmitry. „CHOICE OF QUALITY FACTORS OF AUTOMATIC CONTROL OF UNDERGROUND VENTILATIION“. Interexpo GEO-Siberia 2, Nr. 4 (2019): 33–37. http://dx.doi.org/10.33764/2618-981x-2019-2-4-33-37.
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The analysis of main quality factors of automatic control under the position of its application in control of ventilation at underground of small depth is carried out. The choice of quality factors list of automatic control of regulating system of tunnel ventilator rotor speed and regulating system of throttle angle of air distribution controller is justified.
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Abbasov, A. E. „Mathematical model of management of recirculation of motor aggregates“. Informacionno-technologicheskij vestnik 12, Nr. 2 (30.06.2017): 25–35. http://dx.doi.org/10.21499/2409-1650-2017-2-25-35.
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A mathematical model of management of recirculation of motor units is developed. It is shown that the efficiency of recirculation control is achieved with a decrease in the content of toxic substances in the exhaust; Limiting the maximum combustion temperature of the fuel and the pressure in the combustion chamber; Speed control. Based on the mathematical model, an algorithm is developed for calculating the control dependence for the regulation of the position of the electromechanical recirculation valve in specialized graphic computer environments with three-dimensional and two-dimensional visualization of analysis and calculation results. Calculation of the amount of emissions of harmful substances without the developed algorithm and using the developed algorithm is carried out.
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Sahri, Younes, Salah Tamalouzt und Sofia Belaid Lalouni. „Enhanced Direct Power Control Strategy of a DFIG-Based Wind Energy Conversion System Operating Under Random Conditions“. Periodica Polytechnica Electrical Engineering and Computer Science 65, Nr. 3 (07.06.2021): 196–206. http://dx.doi.org/10.3311/ppee.16656.
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The main objective of this paper is the performances analysis of an Enhanced Direct Power Control (EDPC), applied to Doubly Fed Induction Generator (DFIG) driven by variable speed Wind Turbine (WT). This control strategy uses hysteresis regulators and switching table for active and reactive powers control. These latter are estimated using rotor currents and grid voltages instead of a traditional measurement of stator currents. In addition, the EDPC switching table is based on the position of the rotor flux instead of the stator flux in order to have better regulation accuracy because the rotor voltage vector directly influences the rotor flux and has a proportional relationship with the active and reactive powers. All the operating modes (sub-synchronous, super-synchronous, synchronous and over-speed) of the variable speed WT-DFIG system and the possibility of local reactive power compensation are reported and discussed in this paper. Depending on the operating zone of the WT, Maximum Power Point Tracking (MPPT) technique and pitch angle control are considered to optimize the wind energy efficiency. The validation of the proposed EDPC strategy has been performed through simulation tests under MATALB/Simulink, the obtained results show robustness and good performances with low THD of the generated currents.
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Genov, Julian. „Some aspects of the influence of the vertical wind speed gradient on the blade aerodynamics loads in high class wind generators“. MATEC Web of Conferences 234 (2018): 04006. http://dx.doi.org/10.1051/matecconf/201823404006.
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The powerful wind generators, producing electric power on the order of megawatts are with impressive sizes. The studies on the interaction between the air flow and the wind turbine usually assume the airflow as homogeneous in vertical direction. While for smaller wind turbines this assumption does not lead to significant inaccuracies, for powerful generators the vertical gradient of the wind velocity causes a dependence of the aerodynamic interaction from the angle of rotation of the propeller and leads to a significant cyclic variability of the forces and moments acting on the blades, even for a flow considered as stationary in time. The study of this problem is important for strength loads and fatigue calculations as well as for an implementation of an individual pitch-control of the blades, which could allow a synthesis of a regulation depending on the angular position of the turbine. This could contribute to higher performance and higher reliability.
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Brackenbury, J. „Regulation of swimming in the Culex pipiens (Diptera, Culicidae) pupa: kinematics and locomotory trajectories“. Journal of Experimental Biology 202, Nr. 18 (15.09.1999): 2521–29. http://dx.doi.org/10.1242/jeb.202.18.2521.
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High-speed videography was used to investigate swimming kinematics and locomotory trajectories during escape responses in the pupa of Culex pipiens (Diptera, Culicidae). The pupa can perform straight-line motion despite undergoing backward and forward somersaults through 400 degrees at a rate of 20 s(−)(1). For linear motion to occur, the effective stroke of the abdomen must be delivered during the part of each cycle when the body is facing forwards, allowing passive rotation to carry the body round to the correct position for the start of the next half-stroke. On-off motion of the abdomen is regulated by a click mechanism based on stressed integumentary plates which buckle at strategic points in the cycle. The importance of self-inertia as a component in positional regulation was demonstrated by increasing the kinematic viscosity of the medium: this retarded rotation and resulted in somersaulting on the spot. Whereas normally the pupa invariably directs its swimming downwards, reversal of the usual light gradient produced upward paths as well. It is concluded that straight-line motion is generated automatically by the locomotory machine without any need for sensory feedback about body orientation during each cycle, but that swimming direction can be influenced by sensory cues such as light.
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Wu, Y. C., Zhi Yong Zuo und Y. Sun. „Applied Research of Full Digital Electric Control Systems on Rebuild Machine Tool“. Materials Science Forum 626-627 (August 2009): 399–404. http://dx.doi.org/10.4028/www.scientific.net/msf.626-627.399.
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Taking account of the situation of many old-fashioned imported machine tools, this paper proposes some favourable methods of rebuilding equipment. In theory and practice, with full digital electric system of modern automation technology, rebuilt equipments are easy to operate and reduce energy consumption, raise production efficiency. It realizes the aim of Environment-friendly and resource-economical. In this paper, it also gives three typical examples of rebuilding equipment, table planning machine made in Germany, D2300 lathe and 745A slotter made in Russia. Some pragmatic issues have been discussed, e.g. design optimization for speed regulation of main drive, position finding of cutter frame and synchro control between lathe tools feeding and lathe chuck turning. Finally, it gives the results of the operational curves of rebuilding equipment and relevant data.
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Dzhylkychiev, A. I., A. R. Bekboev und M. K. Zhylkychiev. „STUDIES OF STATIC CHARACTERISTICS OF MEMBRANE CONTROLLING-CONTROLLING ELEMENTS OF A HYDROCYLINDER STEM MOVEMENT SPEED CONVERTER“. Nauka v sovremennom mire, Nr. 3(48) (20.04.2020): 73–79. http://dx.doi.org/10.31618/2524-0935-2020-48-3-1.
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This article discusses the static characteristics of membrane locking and regulating elements and to determine the static characteristics of flat and cylindrical membranes, a special device was developed and manufactured that allows you to record the deviation of the generatrix of the membrane when it is deformed from its original position. Theoretical and experimental studies of flat and cylindrical membrane shut-off and control elements were carried out, results were obtained, dependency graphs were constructed and conclusions were drawn.
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Hakami, Samer, Ibrahim Mohd Alsofyani und Kyo-Beum Lee. „Low-Speed Performance Improvement of Direct Torque Control for Induction Motor Drives Fed by Three-Level NPC Inverter“. Electronics 9, Nr. 1 (01.01.2020): 77. http://dx.doi.org/10.3390/electronics9010077.
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Classical direct torque control (DTC) is considered one of the simplest and fastest control algorithms in motor drives. However, it produces high torque and flux ripples due to the implementation of the three-level hysteresis torque regulator (HTR). Although, increasing the level of HTR and utilizing multilevel inverters has a great contribution in torque and flux ripples reduction, stator flux magnitude of induction motor (IM) droops at every switching sector transition, particularly at low-speed operation. This problem occurs due to the utilization of a zero voltage vector, where the domination of stator resistance is very high. A simple flux regulation strategy (SFRS) is applied for low-speed operation for DTC of IM. The proposed DTC-SFRS modifies the output status of the five-level HTR depending on the flux error, torque error, and stator flux position. This method regulates the stator flux for both forward and reverse rotational directions of IM with retaining the basic structure of classical DTC. By using the proposed algorithm, the stator flux is regulated, hence pure sinusoidal current waveform is achieved, which results in lower total harmonics distortion (THD). The effectiveness of the proposed DTC-SFRS is verified through simulation and experimental results.
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Xu, Zheng Tan, und Song Fa Wu. „Research on Optimization and Modification of Primary Air System of Circulating Fluidized Bed Boiler“. Advanced Materials Research 516-517 (Mai 2012): 778–83. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.778.
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Due to great loss of energy consumption and too high temperature of exhaust in Circulating Fluidized Bed Boiler, the paper investigates how to optimize and modify the primary air system. Changing the traditional way of modulating the position of adjustable plate to regulating the speed of electrical machine by frequency converter, the amount of primary air and pressure is reduced and the goal of energy-saving and consumption-decreasing is achieved.
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Yamada, T., D. A. Suzuki und R. D. Yee. „Smooth pursuitlike eye movements evoked by microstimulation in macaque nucleus reticularis tegmenti pontis“. Journal of Neurophysiology 76, Nr. 5 (01.11.1996): 3313–24. http://dx.doi.org/10.1152/jn.1996.76.5.3313.
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1. Smooth pursuitlike eye movements were evoked with low current microstimulation delivered to rostral portions of the nucleus reticularis tegmenti pontis (rNRTP) in alert macaques. Microstimulation sites were selected by the observation of modulations in single-cell firing rates that were correlated with periodic smoothpursuit eye movements. Current intensities ranged from 10 to 120 microA and were routinely < 40 microA. Microstimulation was delivered either in the dark with no fixation, 100 ms after a fixation target was extinguished, or during maintained fixation of a stationary or moving target. Evoked eye movements also were studied under open-loop conditions with the target image stabilized on the retina. 2. Eye movements evoked in the absence of a target rapidly accelerated to a constant velocity that was maintained for the duration of the microstimulation. Evoked eye speeds ranged from 3.7 to 23 deg/s and averaged 11 deg/s. Evoked eye speed appeared to be linearly related to initial eye position with a sensitivity to initial eye position that averaged 0.23 deg.s-1.deg-1. While some horizontal and oblique smooth eye movements were elicited, microstimulation resulted in upward eye movements in 89% of the sites. 3. Evoked eye speed was found to be dependent on microstimulation pulse frequency and current intensity. Within limits, evoked eye speed increased with increases in stimulation frequency or current intensity. For stimulation frequencies < 300–400 Hz, only smooth pursuit-like eye movements were evoked. At higher stimulation frequencies, accompanying saccades consistently were elicited. 4. Feedback of retinal image motion interacted with the evoked eye movements to decrease eye speed if the visual motion was in the opposite direction as the evoked, pursuit-like eye movements. 5. The results implicate rNRTP as part of the neuronal substrate that controls smooth-pursuit eye movements. NRTP appears to be divided functionally into a rostral, pursuit-related portion and a caudal, saccade-related area. rNRTP is a component of a corticopontocerebellar circuit that presumably involves the pursuit area of the frontal eye field and that parallels the middle and medial superior temporal cerebral cortical/dorsalateral pontine nucleus (MT/MST-DLPN-cerebellum) pathway known to be involved also with regulating smooth-pursuit eye movements.