Automatic Balancing System Research Articles

Pneumatic-liquid Type Automatic Balancing System for Large-scale Rotating Equipment

Pneumatic-liquid Type Automatic Balancing System for Large-scale Rotating Equipment

Research on Novel Electromagnetic Automatic Balancing System for High-end Mechanical Equipment

Research on Novel Electromagnetic Automatic Balancing System for High-end Mechanical Equipment

Correlation of Femoral Muscle Volume Using Three-Dimensional Modeling and Locomotor Function After Unilateral Trans-femoral Amputation.

To evaluate the relationship between femoral muscle volume (FMV) and physiological outcomes after trans-femoral amputations (TFAs) affecting overall locomotor function in patients. Seven individuals who underwent TFA and had been using a prosthesis participated in this cross-sectional study. Gait and balance were assessed using clinical tests, such as 10-m walk test, 6-minute walk test, Berg Balance Scale, and automatic balance system. Respiratory gas analysis was performed to check oxygen consumption rate. Five participants were evaluated for bilateral FMV by MR imaging and FMV was reconstructed using three-dimentional remodeling. In five participants, significant differences were found between the non-involved and involved sides in femur length, total FMV, and functional muscle volume (all p<0.01) in all groups except for the hip adductor volume. The %mean difference between the non-involved and involved sides was 30% for femur length, 52.55% for hip flexor volume, 26.55% for hip adductor volume, 51.86% for hip extensor volume, and 60.21% for knee extensor volume. The hip flexor volume to hip extensor volume ratio in the involved limb and oxygen consumption rate during comfortable gait were negatively correlated (r=-0.96, p=0.04). In individuals who underwent unilateral TFA, hip girdle muscle imbalance in the involved limbs may be associated with oxygen consumption rate while using a prosthesis.

Research on Pneumatic–liquid On-Line Automatic Balance Technology for High-End Turbine Units

Rotor mass imbalance is the main cause of vibration overload of high-end turbine units, which can easily induce a variety of failures such as shaft tile and seal wear, and blade breakage. The online automatic balancing system can solve the problem of imbalance of rotor mass during the operation of the equipment, and at the same time can ensure the long-term stable operation of the equipment. Therefore, a new pneumatic–liquid on-line automatic balance (PLOABS) system is proposed for high-end turbine units, which has the advantages of simple structure, no moving parts in the rotating element, closed action environment, reversible balancing process and can maintain the original state when restarted. Using ANSYS software, the gas driving force and the internal gas–liquid rotating flow field of the actuator are simulated and analyzed, and the actuator structure has been further optimized. At the same time, a set of the PLOABS system is built to conduct automatic balancing experiments. The results showed that the rotor amplitude was reduced from 18.3 to 10.6 μm, which verified the feasibility and effectiveness of the PLOABS technology and laid the foundation for the subsequent engineering application of the PLOABS technology.

Development of CubeSat Magnetic Torquer Testing System in a Vacuum Environment

This paper discusses the development and instrumentation of an integrated facility based on an air-bearing table to test small ADCS actuators such as electric propulsion devices, reaction wheels, and magnetic torquers for CubeSats. It includes an automatic balancing system that corrects the center of mass of the testing platform and a Helmholtz cage for the simulation of the in-orbit geomagnetic environment inside the vacuum environment. Through experimental tests, it was observed that the attitude disturbances due to the aerodynamic drag and the viscous rotational friction in atmospheric conditions (~5×10-6 Nm) can be significantly decreased when the testing platform is placed inside a vacuum environment (~5×10-7 Nm). It was also observed that the vacuum condition facilitates the verification test of attitude control maneuvers using small magnetic torquers for CubeSats whose control torque is smaller than the attitude disturbance torque in atmospheric conditions. A demonstration test was performed to verify the attitude stabilization control by the magnetic torquers in vacuum conditions under a simulated geomagnetic field as in the International Space Station orbit using this integrated testing facility.

Method for calculating dynamic loads and energy consumption of a sucker rod installation with an automatic balancing system

The efficiency of sucker rod pump installations, which have become widespread in mechanized lift practice, is largely determined by the balance of the drive. During the operation of sucker rod installations, the balance of loads acting on the rod string and the drive can change significantly due to changes in the dynamic fluid level, which leads to a decrease in balance and an increase in loads on the pumping equipment units. The increase and decrease in the dynamic level in accordance with the pumping and accumulation cycle occurs in wells operating in the periodic pumping mode. &#x0D; It is shown that during the operation of equipment in a periodic mode, fluctuations in the dynamic level and, accordingly, in the loads acting on the nodes occur. This leads to the need for dynamic adjustment of the balancing weights to ensure the balance of the pumping unit. A system for automatic balancing of the rod drive has been developed, including a balancing counterweight, an electric motor that moves the load along the balance beam, a propeller and a computing unit.&#x0D; To study the effectiveness of the proposed device, a complex mathematical model of the joint operation of the reservoir - well - sucker rod pump - rod string – pumping unit has been developed. It is shown that due to the dynamic adjustment of the balance counterweight position, the automatic balancing system makes it possible to significantly reduce the amplitude value of the torque on the crank shaft (in comparison with the traditional rod installation) and provide a more uniform load of the electric motor. Equalization of torque and motor load reduces the power consumption of the unit.

Automatic Balancing System in Quadcopter with Change in Center of Gravity

The purpose of this paper is to explore an automatic balancing system using the proportional integral derivative or PID feedback control algorithm in quad-rotor Helicopter, so-called quadcopter, with the center of gravity, moved on account of payload. Nowadays, the quadcopter widely used for a variety of applications due to high stability performance. In many applications in quadcopter usually carried a payload in the middle of its frame to maintain the balance during flight. However, the application of quadcopter could be a contributing factor to increase a payload on one side and can lead to an improper position of the center of gravity. This study set out to investigate the use of the mass of battery and landing gear to create a counterbalance to compensate for the payload. The stabilization of the balancing system was implemented by the PID control algorithm to control the counterbalancing of the quadcopter. The current study found that the PID control algorithm works well to maintain the balance in a quadcopter with the center of gravity moving during flight.

An Optimized Pulse-Counting Method for Compensation Vector Calculation in the Automatic Balancer

The accuracy of the counterweight positions in an automatic balancing system deeply affects dynamic balancing. Compensation vector is synthesized by the two counterweights located in the electromagnetic dual-weight automatic balancer. Therefore, if the position of the counterweight is inaccurate, it may result in a wrong adjustment and a larger imbalance of the rotor system. In this paper, an optimized pulse counting method for compensation vector calculation in an electromagnetic dual-weight balancing system is proposed based on a programmable logic controller (PLC). A propeller automatic balancing simulation test bench is used to verify the effect of the method by obtaining the positions of the counterweights and synthesizing the compensation vector in the working mode. The error is less than 1/80 which means that it does not exceed one step in the 80-position-balancer at 1200 rpm. The proposed control system can work without computers or high-speed data acquisition equipment, which improves the stability and flexibility of the control system, facilitates the design of the automatic balancing system, and shows excellent potential for industrial applications.

Automatic mass balancing system for a dynamic CubeSat attitude simulator: development and experimental validation

This paper describes the automatic balancing and inertia identification system for three degrees of freedom CubeSat attitude simulator testbed. For a reliable verification of the attitude determination and control subsystem, the on-orbit environment shall be simulated within the testbed, minimizing the external disturbances acting on the satellite mock-up. The gravity torque is expected to be the largest among the disturbances, and an automatic balancing procedure can largely reduce the time necessary for tuning the platform and minimize the residual torque. The automatic balancing system adopted in this work employs three sliding masses independently actuated by three electric motors using a two-step procedure. In the first step, a feedback control is employed for a plane balancing. The inertia parameters and the remaining offset component are then estimated by collecting free oscillating platform data. This two-step procedure is iterated towards increasingly finer balancing until no further improvement is obtained. For the planar balancing, a control law based on linearized equations and a newly developed nonlinear feedback law is implemented and compared, showing the superior performance of the latter. The unbalance offset vector component along the local vertical and inertia tensor are estimated by a constrained batch least squares filter. Experimental results show the effectiveness of the implemented approach, which leads to a residual disturbance torque acting on the balanced platform smaller than 5 × 10–5 Nm.

A Dynamic Testbed for Nanosatellites Attitude Verification

To enable a reliable verification of attitude determination and control systems for nanosatellites, the environment of low Earth orbits with almost disturbance-free rotational dynamics must be simulated. This work describes the design solutions adopted for developing a dynamic nanosatellite attitude simulator testbed at the University of Bologna. The facility integrates several subsystems, including: (i) an air-bearing three degree of freedom platform, with automatic balancing system, (ii) a Helmholtz cage for geomagnetic field simulation, (iii) a Sun simulator, and (iv) a metrology vision system for ground-truth attitude generation. Apart from the commercial off-the-shelf Helmholtz cage, the other subsystems required substantial development efforts. The main purpose of this manuscript is to offer some cost-effective solutions for their in-house development, and to show through experimental verification that adequate performances can be achieved. The proposed approach may thus be preferred to the procurement of turn-key solutions, when required by budget constraints. The main outcome of the commissioning phase of the facility are: a residual disturbance torque affecting the air bearing platform of less than 5 × 10−5 Nm, an attitude determination rms accuracy of the vision system of 10 arcmin, and divergence of the Sun simulator light beam of less than 0.5° in a 35 cm diameter area.

Mass properties identification and automatic mass balancing system for satellite attitude dynamics simulator

A Satellite Attitude Dynamics Simulator is a low-cost, ground-based system made to simulate the conditions of a weightless satellite in space. The identification of the mass characteristics is crucial for Satellite Attitude Dynamics Simulator application and so the center of mass place is necessary for balancing the platform and moment of inertia which is a significant factor in designing controllers and selecting actuators. The purposes of this paper are the mass properties identification and design, experimentation, and validation of an automatic mass balancing system, which is assembled on the Satellite Attitude Dynamics Simulator at the Space Research Laboratory. This paper presents a process of mass properties estimation for the Satellite Attitude Dynamics Simulator using classical Levenberg–Marquardt as an optimization method. By employing this technique lack of repeatability and difficulties in implementation will be eliminated. In order to verify this technique, a MATLAB® SIMULINK® model of the Satellite Attitude Dynamics Simulator is established. The gap between the center of mass and center of rotation is decreased by means of the automatic mass balancing system in order to remove gravity disturbance. The results of this identification process are compared to the recursive least square algorithm, which is commonly employed in identification of mass properties. The analytical and experimental results prove that the proposed characteristic estimation process using classical Levenberg–Marquardt algorithm is more effective and appropriate. Proper excitation of the platform will guarantee the accuracy of estimation and compensation of the center of gravity offset utilizing the balancing system.

Synthesis and research of automatic balancing system of voltage converter fed induction motor currents

Synthesis of methods for investigating unbalanced operating conditions of thyristor voltage converter fed induction motors is performed. The voltage unbalance factors of the power source are calculated, and the formation conditions are determined. Attention is paid to the harmonic analysis of the induction motor currents. The influence of power source voltage unbalance on the induction motor performance is determined on the basis of simulation and experiments. The results of power source unbalance - phase current unbalance, overload capacity reduction, oscillating nature of torque and speed, dynamics deterioration are outlined. The system of automatic balancing of the induction motor stator currents using the thyristor voltage converter is proposed. The synthesis of the elements of control channels and feedback channels of the balancing system, as well as operation principles, are examined. It is determined that balancing reduces the current unbalance factors by more than an order of magnitude, and virtually ensures the equality of the active stator currents in the induction motor phases. The benefits and drawbacks of the automatic balancing system are presented, and recommendations on its application are given.

5軸能動形磁気軸受における不釣り合い振動補償群の関係性とそれを活用した振動抑制

An active magnetic bearing (AMB) is utilized widely in vacuum apparatuses such as a turbo molecular pump (TMP). The rotor supported by the AMB in the TMP is vibrated by the unbalance of the mass of the rotor, the electromagnetic force of the AMB and the location of the AMB. As the methods to suppress this vibration, phase-variable type Peak-of-Gain Control (JIS B 0913-1, Unbalance Force Counteracting Control: UFCC), phase-variable type Automatic Balancing System (JIS B 0913-1, Unbalance Force Rejection Control: UFRC) and Phase-Variable Control (PVC) have been reported. The UFCC (UFRC) suppresses the vibration by increasing (decreasing) the bearing stiffness and giving the damping effects at the rotational frequency. However, the relationship between the UFCC and the UFRC is not expressed. Accordingly, we investigate the UFCC (UFRC) is corresponded to the UFRC (UFCC) by using the phase changes. On the other hand, the repetitive control which is one of the periodic disturbance suppression methods also has been proposed. The control suppresses the unbalance vibration based on the internal model principle. For the unbalance vibration compensation, we clarify the UFCC is considered as repetitive control by using the pole assignment. Moreover, we show the unbalance vibration is further suppressed by using the UFCC which is corresponded to the rotational frequency and the second harmonic.

Automatic Mass Balancing of a Spacecraft Three-Axis Simulator: Analysis and Experimentation

Spacecraft three-axis simulators provide frictionless and, ideally, torque-free hardware simulation platforms that are crucial for validating spacecraft attitude determination and control strategies. To reduce the gravitational torque, the distance between the simulator center of mass and the center of rotation needs to be minimized. This work proposes an automatic mass balancing system for spacecraft simulators, which uses only the three sliding masses during the balancing process, without need of further actuators. The proposed method is based on an adaptive nonlinear feedback control that aims to move, in real time, the center of mass toward the spacecraft simulator’s center of rotation. The stability of the feedback system and the convergence of the estimated unknown parameter (the distance between the center of mass and the center of rotation) are analyzed through Lyapunov stability theory. The proposed method is experimentally validated using the CubeSat Three-Axis Simulator at the Spacecraft Robotics Laboratory of the Naval Postgraduate School.

Design of an Automatic Magnetic Balance System

Along with the fast development of high-technology fields in China, especially in aviation and aerospace, in order to meet the fast and accurate detection requirements of various magnetic material properties, to solve artificial measurement error and low efficiency on the current manual measuring way, a kind of automatic magnetic balance system was developed. The mechanism design, measurement &amp; control system design and the main technical indicators were also described. The application results show that the automatic magnetic balance system can work stable and reliable, and the test capacity of the system is effectively expanded because of higher precision, higher measuring efficiency and more convenient operation, so the system can satisfy the testing requirements in the process such as scientific research, manufacture, teaching and etc.

Cylinder-to-cylinder variation sources in diesel low temperature combustion and the influence they have on emissions

Cylinder-to-cylinder variation in a multi-cylinder diesel engine was found to increase substantially when transitioning to a low-temperature combustion mode. This study was started to investigate the potential influence this effect could have on the emissions levels. Initial testing showed an imbalance in the fuel distribution that prompted this article to focus on data from before and after swapping two injectors under both conventional and low-temperature combustion modes. A significant improvement is observed in cylinder variation based both on visual heat release inspection and on mean effective pressure variation. This is likely a result of a changing combination of exhaust gas recirculation and fuel distribution such that less cylinder-to-cylinder variation is present (e.g. high dilution and low fuel, switched to low dilution and low fuel). Interestingly, despite the reduced cylinder-to-cylinder variation, the results show that the emissions levels are actually not affected. Despite the lack of influence on emissions results, the cylinder-to-cylinder variation in low-temperature combustion modes is still a critical factor that could impact its ability to be implemented in a commercial setting. Further cylinder balancing was attempted and achieved by introducing small (microsecond) adjustments to each cylinder start of injection and injection duration. The balancing is effective, but due to exhaust gas recirculation imbalance, a single adjustment setting does not apply to both conventional and low-temperature combustion modes. Additionally, day-to-day ambient conditions also negate the effectiveness. This supports the idea that some type of consumer-based real-time automatic balancing system may be needed in the future.

A design method of a mode control and an unbalance vibration control for five-axes active magnetic bearing systems

Mass unbalance of magnetically levitated rotors causes deteriorations of dynamic and static characteristics. To avoid this problem, it is necessary that mode matrices (i.e., a mode selection/distribution matrices) are adjusted appropriately. This is because these matrices are set based on the rotor’s centre of gravity and magnetic force coefficients of electromagnets. It takes long time to adjust the parameters of the mode matrices by trial and error. To design these parameters efficiently, we propose an adjustment method based on experimental analysis. Experimental results of step response show effectiveness of the proposed method. On the other hand, the eccentricity of the rotor causes unbalanced vibration, which is a common problem in rotating machinery. To suppress the vibration, automatic balancing system (ABS) and peak-of-gain control (PGC) are utilised. By using the ABS (the PGC), the bearing stiffness at rotational frequency is decreased (increased). In previous works, implementation methods for these have not been presented fully. Thus, in this paper, we considered the implementation of the ABS and the PGC. Moreover, practical advantages of the PGC/ABS are demonstrated by rotational tests of a turbo molecular pump.

A newly developed state-of-the-art geotechnical centrifuge in Korea

The first large scale geotechnical centrifuge in Korea has recently been developed at KAIST under the Korea Construction Engineering Development (KOCED) Collaboratory program. A 5 m platform radius, 240 g-tons state-of-the-art geotechnical centrifuge has been installed in a new facility. The centrifuge has the unique feature of an automatic balancing system and includes parts for general testing purposes such as fluid rotary joints, slip rings, a fiber optic rotary joint and an Ethernet network system. In addition, a four degree-of-freedom in-flight robot can be equipped to simulate complex construction or in-situ testing process during centrifuge flight. In order to simulate earthquake motion during operation, a self-balancing type biaxial shaking table has also been developed. Since the KOCED program promotes collaboration and remote use, tele-presence and tele-participation environments have been implemented in this facility.

Modeling and Analysis of Multi-Objective Automatic Balance System in the Hydrometallurgical Process

During the hydrometallurgical production process, there are many towers working at the same time. In order to improve production efficiency, we need to control the level height of every tower. Takes example for 6 towers, do research on the level control system in metal ions production process. According to the theory of materials balance, the mathematic model of the system are established. Programmed the mathematic model by Matlab. In order to make the level of each tower at the same height, work out how many adjust times needed and how much adsorbate every tower inflow and outflow each time. Then analysis the data results of error and variance, which have confirmed the feasibility and rationality of the level automatic balance system model established in this paper.

Estimating Influence of Inertial Resistance of Throttle for Hydraulic Balancing Device On Rotor Axial Vibration

There had been considered axial vibration of the rotor equipped with an automatic balancing system for axial forces. There were constructed amplitude and phase frequency characteristics, as well as evaluated influence of inertial resistance into throttling channels of auto discharge system. There were identified damping properties of resistance devices.