Optimal Design of Novel Electromagnetic-Ring Active Balancing Actuator with Radial Excitation

Imbalance vibration is a typical failure mode of rotational machines and has significant negative effects on the efficiency,accuracy,and service life of equipment.To automatically reduce the imbalance vibration during the operational process,different types of active balancing actuators have been designed and widely applied in actual production.However,the existing electromagnetic-ring active balancing actuator is designed based on an axial excitation structure which can cause structural instability and has low electromagnetic driving efficiency.In this paper,a novel radial excitation structure and the working principle of an electromagnetic-ring active balancing actuator with a combined driving strategy are presented in detail.Then,based on a finite element model,the performance parameters of the actuator are analyzed,and reasonable design parameters are obtained.Self-locking torque measurements and comparative static and dynamic experiments are performed to validate the self-locking torque and driving efficiency of the actuator.The results indicate that this novel active balancing actuator has sufficient self-locking torque,achieves normal step rotation at 2000 r/min,and reduces the driving voltage by 12.5%.The proposed novel balancing actuator using radial excitation and a combination of permanent magnets and soft-iron blocks has improved electromagnetic efficiency and a more stable and compact structure.

Regularized inversion for coseismic slip distribution with active constraint balancing

Estimating the spatial distribution of coseismic slip is an ill-posed inverse problem, and solutions may be extremely oscillatory due to measurement errors without any constraints on the coseismic slip distribution. In order to obtain stable solution for coseismic slip inversion, regularization method with smoothness-constrained was imposed. Trade-off parameter in regularized inversion, which balances the minimization of the data misfit and model roughness, should be a critical procedure to achieve both resolution and stability. Then, the active constraint balancing approach is adopted, in which the trade-off parameter is regarded as a spatial variable at each model parameter and automatically determined via the model resolution matrix and the spread function. Numerical experiments for a synthetical model indicate that regularized inversion using active constraint balancing approach can provides stable inversion results and have low sensitivity to the knowledge of the exact character of the Gaussian noise. Regularized inversion combined with active constraint balancing approach is conducted on the 2005 Nias earthquake. The released moment based on the estimated coseismic slip distribution is 9.91×1021 N·m, which is equivalent to a moment magnitude of 8.6 and almost identical to the value determined by USGS. The inversion results for synthetic coseismic uniform-slip model and the 2005 earthquake show that smoothness-constrained regularized inversion method combined with active constraint balancing approach is effective, and can be reasonable to reconstruct coseismic slip distribution on fault.

Study on online elimination of sudden unbalance-induced vibration using active balancing technology

An active balancing technology has been applied to solve the severe vibration caused by sudden unbalance in rotating machineries during their working process. First, based on the generation principle of sudden unbalance, a simulation test stand with a sudden unbalance generation device was set up. Then, the balancing planes were optimized by using the finite element method （FEM） to determine the position for balancing device installation. Finally, the active balancing experiments were carried out on the test stand. The experimental results indicate that the vibration response caused by sudden unbalance can be decreased from 77μm to 8μm by using the active balancing device, and the vibration amplitude reduction was up to 89.6%. From this example, it can be concluded that the active balancing device, which is installed on a proper position of the rotor, can effectively control the random transient synchronous vibration, demonstrating its high value in engineering practice.

Study on the application of active balancing device to solve the vibration problem for the rotor with bending fault

The rotor with bending faults that occurrs on the rotating machinery usually vibrates seriously. This paper investigates to apply the active balancing device on a flexible rotor with bending faults to solve the vibration problem. Two problems are studied by finite element method firstly： Where the balance actuator is fixed on the shaft and how much the balancing capacity of the active balancing device is needed. The experiment is then carried out on the test rig, which consists of a flexible rotor with bending faults. The test results indicate that the bending rotor peak vibration response can be decreased from 550~m to 40~tm below by using the active balancing device. The peak vibration response decreases approximately by 93 %. The synchronous vibration due to the rotor bending faults can be controlled effectively by using ac- tive balancing device. The active balancing device is especially adapted to solve the problem caused by thermal distortion with time-variation and randomness, which is varied with working conditions, thus it has good practical value in practice.

Adaptive Control of Active Balancing System for a Fast Speed-varying Jeffcott Rotor with Actuator Time Delay

Due to actuator time delay existing in an adaptive control of the active balancing system for a fast speed-varying Jeffcott rotor, if an unsynchronized control force (correction imbalance) is applied to the system, it may lead to degradation in control efficiency and instability of the control system. In order to avoid these shortcomings, a simple adaptive controller was designed for a strictly positive real rotor system with actuator time delay, then a Lyapunov-Krasovskii functional was constructed after an appropriate transform of this sys-tem model, the stability conditions of this adaptive control system with actuator time delay were derived. After adding a filter function, the active balancing system for the fast speed-varying Jeffcott rotor with actuator time delay can easily be converted to a strictly positive real system, and thus it can use the above adaptive controller satisfying the stability conditions. Finally, numerical simulations show that the adaptive controller proposed works very well to perform the active balancing for the fast speed-varying Jeffcott rotor with actuator time delay.

Design and experimental study of active balancing actuator driven by ultrasonic motor

The on-line active balancing system can suppress the vibration caused by unbalance of rotating equipment in real time,and is of great strategic significance for high-end equipment in machining,aviation and other fields.As the core equipment of the on-line active balancing system,the performance parameters of the active balancing actuator determine the overall performance of the balancing system.The balancing method of the existing mechanical balancing actuator is improved,and a new active balancing actuator structure based on ultrasonic motor is proposed.The stress distribution of the actuator is analyzed by establishing a three-dimensional model of the actuator.The feasibility and effectiveness of the above structure are verified by the experimental research on the grinder.The results show that the active balancing actuator based on ultrasonic motor can drive the counterweight to complete the required self-locking and stepping actions in the whole cycle.The structural design scheme is feasible.At the same time,it also shows that the actuator can suppress the unbalance vibration of the grinder.The active balancing actuator based on ultrasonic motor drive studied in this paper lays a foundation for the industrial application of this kind of actuator in the future.

Effects of Balanced Fertilization on Mulberry Leaf Quality and Its Active Substance Content

This paper study the effect of nitrogen （N, X1）, phosphorus （P, X2） and potassium （K, X3） in different amounts on crude protein, soluble sugar, total flavonoid and 1-deoxynojirimycin contents in mulberry leaves, with mulberry trees in spring and autumn as the material and as per ＂3414＂ experimental design. The results showed that the qualities and active substance content of mulberry leaves changed from increasing to decreasing with its development; crude protein and solu-ble sugar achieved the peak on August 20; total flavonoid and 1-deoxynojirimycin was the highest on May 15. Fertilizations with N, P and K fertilizers at different amounts had significant effects on quality of mulberry leaf and content of active substances. Specifically, as fertilizer amount increased, the content of active sub- stances grew dramatically and achieved the highest at level 2 （X^2X=X~_）. Based on fertilizer effect functions of objective yield, the recommended amounts of N, P and K fertilizers based on crude protein, soluble sugar, flavonoid content and DNJ in test sites were 718.46, 220.11 and 305.23 kg/hm2, when the highest of crude protein in mulberry leaf was 1 813.83 kg/hm2. When N, P and K fertilizers were recommended at 666.54, 204.41 and 243.18 kg/hm2, soluble sugar in mulberry leaf achieved the peak at 1 042.65 kg/hm2. When N, P and K fertilizers were at 675.96, 326.49 and 462.90 kg/hm2, flavonoid content achieved the maximum at 147.90 kg/hm2. When N, P and K fertilizers were at 720.9, 225.11 and 323.63 kg/hm2, DNJ content was the highest at 13.55 kg/hm2.

Balancing sub‐reaction activity to boost electrocatalytic urea synthesis using a metal‐free electrocatalyst

Electrocatalytic urea synthesis via coupling of nitrate with CO_(2)is considered as a promising alternative to the industrial urea synthetic process.However,the requirement of sub-reaction(NO_(3)RR and CO_(2)RR)activities for efficient urea synthesis is not clear and the related reaction mechanisms remain obscure.Here,the construction,breaking,and rebuilding of the sub-reaction activity balance would be accompanied by the corresponding regulation in urea synthesis,and the balance of sub-reaction activities was proven to play a vital role in efficient urea synthesis.With rational design,a urea yield rate of 610.6 mg h−1 gcat.−1 was realized on the N-doped carbon electrocatalyst,superior to that of noble-metal electrocatalysts.Based on the operando SRFTIR measurements,we proposed that urea synthesis arises from the coupling of^(*)NO and^(*)CO to generate the key intermediate of^(*)OCNO.This work provides new insights and guidelines into urea synthesis from the aspect of activity balance.

Conception and Design of Active Balancer for Planar Mechanisms

The dynamic balancing is an important issue in mechanism design. For the existing balancing methods, both passive and active ones, there is still room for improvement in adaplability and independency. In view of this, a concept of active balancer is developed as a new solution for the dynamic balancing with more flexibility. The proposed balancer is an independent additional device with a control system inside, which consists of a two-degree-of-freedom （DOF） linkage and a controllable motor, and can be attached to a machine expediently with little change to its original structure and motion. One of the two inputs of the two-DOF linkage shares the same shaft with its output, which is connected to the input shaft of a machine to be balanced and driven by the original actuator. The other input is driven by the control motor. By properly selecting the speed trajectories of the control motor and link parameters of the two-DOF linkage, one or more dynamic effects of the mechanisms can be minimized or eliminated adaptively. The design procedure of the active balancer is put forward and a two-step optimization is developed to find out optimal design parameters of the balancer for various design requirements and constraints. Taking a force-balanced crank-rocker mechanism as the reference mechanism, numerical examples are given to illustrate the design procedure. The balancing effects of the proposed balancer are compared with those of the existing adding dyads （DYAD） method. The results show that the introduction of the control system provides the active balancer with better balancing effect and more flexibility than the DYAD method. A considerable reduction in the dynamic effects （input torque, shaking moment and shaking force） can be achieved for different balancing object by designing the structural and control parameters of the balancer, and the deterioration of dynamic performance caused by alterative working conditions can be compensated effectively by redesigning the control parameters.

Model reduction and active control of flexible beam using internal balance technique

The internal balance technique is effective for the model reduction in flexible structures, especially the ones with dense frequencies. However, due to the difficulty in extracting the internal balance modal coordinates from the physical sensor readings, research on this topic has been mostly theoretical so far, and little has been done in experiments or engineering applications. This paper studies the internal balance method theoretically as well as experimentally and designs an active controller based on the reduction model. The research works on a digital signal processor （DSP） TMS320F2812- based experiment system with a flexible beam and proposes an approximate approach to access the internal balance modal coordinates. The simulation and test results have shown that the proposed approach is feasible and effective, and the designed controller is successful in restraining the beam vibration.

基于ProActive的并行计算任务调度器的研究

ProActive在开发并行计算及网格应用中很受欢迎,但目前还没有可用于基于ProActive的并行计算的任务调度器,在对相关技术进行研究后,给出了一个简单有效的任务调度器的实现方案,介绍了其技术细节。将其应用于开发的基于ProActive的并行计算支持平台中进行了实验,实验结果表明该调度器是可行和有效的。

Performance Evaluation of a Permanent Magnet Electric-Drive- Reconfigured Onboard Charger with Active Power Factor Correction

This paper presents a comprehensive charging operation for an electric-drive-reconfigured onboard charger(EDROC)with active power factor correction(APFC).The charging topology exclusively utilizes the three-phase permanent magnet synchronous motor(PMSM)propulsion system as a three-channel boost-type converter in which only a contactor and a small diode bridge are added.First,the operation scenario of the EDROC is introduced.Second,the relationship between electromagnetic torque and rotor position is investigated.Third,the current ripple cancellation of the EDROC is discussed in detail.Moreover,to implement the single-phase APFC along with charging voltage/current regulation of propulsion battery,control strategies including current balancing and synchronous/interleaving PWM strategies are incorporated.Finally,200W proof-of-concept prototype-based tests are conducted under different operation scenarios.

A Study on PC/104 Embedded Automatic Balancing Control System

In this paper,an embedded real-time control system for automatic rotor balancing was studied.Benefiting from the modular design,this system can be easily re-constituted or expanded under different working conditions.The special designed hardware resists harsh environment.As an embedded application,it was very important to save system consumptions on both hardware and software,so the algorithms for unbalance vibration identification and attenuation were deduced,meantime a unified fast algorithm structure was achieved through the geometric analysis.Based on this structure,the signal processing algorithm was tested by an open data source,while the control algorithm was simulated using a basic rotor model,and then connected to a hyper gravity machine running online auto-balancing.The result confirms that the unbalancing vibration is effectively restrained.

Modeling and Controlling of an Active Power Filter Using Photovoltaic System with Reduced Energy Storage Capacitor

A novel three-phase active power filter （APF） circuit with photovoltaic （PV） system to improve the quality of service and to reduce the capacity of energy storage capacitor is presented. The energy balance concept and sampling technique were used to simplify the calculation algorithm for the required utility source current and to control the voltage of the energy storage capacitor. The feasibility was verified by using the Pspice simulations and experiments. When the APF mode was used during non-operational period, not only the utilization rate, power factor and power quality could be improved, but also the capacity of energy storage capacitor could sparing. As the results, the advantages of the APF circuit are simplicity of control circuits, low cost, and good transient response.

An Investigation into Food Balance and Its Relationship to the Physical Activity Practised within the School Context for Both Males and Females Aged 10-13 Years

The preliminary aim of this study was to reach food balance （quantitative and qualitative） of the meals provided by the school canteen at the Wilaya of Tieret, and its relationship to the physical activity practised, adequately through using a definite method to weight the amounts of food distributed for the meals, and to calculate the energetic expenditure of the physical activity, with an informative exploration of data and the value standards of the dispensed energy that is highly recommended by the （CNRS/CNERA 1992） center. The results of the main findings revealed that the value of macronutrients was smaller than the approved standards. Additionally, the value of the total protein weight per a day was 49.23 g, the fat value as 24.11 g and carbohydrate value as 190.87 g. The results showed also that protein diversity, animal and vegetal fats did not match the standards since the animal protein ratio was 27.76% and the vegetal as 72.24% from the whole total of protein. The percentage of the vegetal fat was 43.49% and the animal 56.31% Moreover, there is a weak correlation between the value of the expended and consumed energy. The Pearson＇s coefficient of males reached 0.09- and 0.39- for females. Furthermore, the value of the consumed energy did not fit the standards recommended for both males and females ages between 10/13 years old. On the basis of the previous pieces of information, we majorly recommend the achievement of a similar investigation for the rest parts of the country in order to reach a balanced nutrition for our children on internal schools.

老年人主动性静态和动态平衡测试的重测信度:Korebalance平衡测量系统

目的研究Korebalance平衡测量系统老年人在主动模式下静态和动态平衡测试的重测信度。方法 20名符合入选条件的老年人参与本研究,应用Korebalance平衡测量系统测试受试者在主动模式下静态和动态平衡能力。在7d后同一时间由同一测试者重复测试1次。用组内相关系数(ICC)分析重测信度。结果主动模式下静态和动态平衡测试具有较好的重测信度(ICC=0.804～0.923)。结论 Korebalance平衡测量系统测试老年人在主动模式下静态和动态平衡能力具有高度重测信度。

A Review on Self-Recovery Regulation(SR)Technique for Unbalance Vibration of High-End Equipment

The high-end equipment represented by high-end machine tools and aero-engines is the core component of the national intelligent manufacturing plan,and the mass unbalance is the main reason for its excessive vibration,that seriously impacts the operation efficiency and running life of the equipment.In order to change the traditional way that the fault of equipment can only be repaired by human,the self-recovery mechanism of human and animal are given to the equipment in this paper,which forms the self-recovery regulation(SR)system for unbalance vibration of high-end equipment.The system can online generate the self-recovery force to restrain the unbalance vibration of the equipment in operation,which is an important direction for the development of the equipment to the advanced intelligent stage.Based on the basic principles of SR technique,the typical engineering application cases of this technique in the field of aeroengine and high-end machine tools are introduced,and four related studies promoting the development of this technique are summarized and analyzed in turn.It includes feature extraction,imbalance location,regulation method and balancing actuator.Self-recovery Regulation(SR)Technique is an important way to realize intelligent manufacturing and intelligent maintenance.Relevant research can lay a technical foundation for the development of high-end equipment with self-health function.

Role of Trunk Rehabilitation on Trunk Control, Balance and Gait in Patients with Chronic Stroke: A Pre-Post Design

Purpose: Although proximal stability of the trunk is a prerequisite for balance and gait, to determine the role of trunk rehabilitation on trunk control, balance and gait in patients with chronic stroke is yet unknown. Method: Fifteen sub-jects (post-stroke duration (3.53 ± 2.98) years) who had the ability to walk 10 meters independently with or without a walking aid;scoring ≤ 21 on Trunk Impairment Scale (TIS), participated in a selective trunk muscle exercise regime, consisting of 45 minutes training per day, four days a week, and for four weeks duration in an outpatient stroke reha-bilitation centre. Results: The overall effect size index for trunk rehabilitation was 1.07. This study showed large effect size index for Trunk Impairment Scale (1.75), Berg Balance Scale (1.65) than for gait variables (0.65). After trunk rehabilitation, there was a significant improvement for gait speed (p= 0.015), cadence (p= 0.001) and gait symmetry (p=0.019) in patients with chronic stroke. In addition, all the spatial gait parameters had a significant change post-intervention. There was no significant change in temporal gait parameters with the exception of affected single limb support time. The level of significance was set at p < 0.05. Conclusion: The exercises consisted of selective trunk movement of the upper and the lower part of trunk had shown larger effect size index for trunk control and balance than for gait in patients with chronic stroke. Future randomized controlled studies incorporating large sample size would provide insight into the effectiveness and clinical relevance of this intervention.

Fault Tolerant Algorithm Based on Dynamic and Active Load Balancing for Redundant Services

A new Some-Read-Any-Write (SRAW) fault tolerant algorithm for redudant services is presented that allows a system to adjust failures dynamically in order to keep the availability and improve the performance. SRAW is based upon dynamic and active load balancing. By introducing dynamic and active load balancing scheme into redundant services, not only the processing speed of requests can be greatly improved, but also the load balancing can be simply and efficiently achieved. Integrated with consistency protocol in this paper, SRAW can also be applied to state services. The performance of SRAW algorithm is also analyzed, and comparisons with other fault tolerant algorithms, expecially with RAWA, indicate that SRAW efficiently improves the performance of redundant services with guaranteeing system availability. Keywords redundant service - fault tolerant - active - load balancing - quorum Supported by the Hebei Province Natural Science Foundation of China under Grant No.600091.Jun-Feng Tian received the B.S. degree in electrical engineering and the M.S. degree in computer application both from Hebei University, in 1986 and in 1995 respectively. Currently, he is a Ph.D. candidate in University of Science and Technology of China. He is a professor at Hebei University. His current research interests include network technology, system architecture and distributed computing.Jun-Wei Zhang was born in 1977 and received the B.S. and M.S. degrees in computer application from Hebei University, P.R. China, in 2000 and 2003, respectively. His current research interests include software fault tolerance and load balancing.Feng-Xian Wang received the B.S. degree in electrical engineering from Hebei University, P.R. China, in 1978. He is a professor in Hebei University. His current research interests include network security and distributed computing.

Active Cell Balancing Control Strategy for Parallelly Connected LiFePO_(4) Batteries

While several recent studies have focused on elimi-nating the imbalance of energy stored in series-connected battery cells,very little attention has been given to balancing the energy stored in parallel-connected battery cells.As such,this paper aims at presenting a new balancing approach for parallel LiFePO_(4) battery cells.In this regard,a Backpropagation Neural Network(BPNN)based technique is employed to develop a Battery Management System(BMS)that can assess the charging status of all cells and control its operations through a DC/DC Buck-Boost converter.Simulation results demonstrate the effectiveness of the proposed approach in balancing the energy stored in parallel-connected battery cells in which the state of charge(SoC)estimation error is found to be only 1.15%.