Influence of spring constant and electromagnetic damping coefficient on measurement performance in a checkweigher with force balance system using Voice Coil Actuator

Spring constants and damping coefficients of a thin lubricant bridge of a perfluoropolyether (PFPE) lubricant intervening between a diamond probe tip and a diamond-like carbon (DLC) surface of a magnetic disk are identified through regression analysis of tip damping vibration. PFPE lubricants with functional end groups were used to form a lubricant bridge between the DLC surface and a probe tip with a notably small curvature radius of 0.1μm. The tip was both retracted from and extended toward the disk surface at four different progressive distances to attain varied elongation of the bridge. It was also vibrated at each step to provide damping waveforms. By applying regression analysis to the observed waveforms, the spring constant and the damping coefficient of the lubricant bridge were identified within an elongation range from 50nm to 800nm. Spring constant of the lubricant bridge kb had a negative value varying from −0.15N∕m to −0.1N∕m. The damping value expressed in the form of frequency-multiplied damping cb×ω ranged from 0.02N∕m to 0.06N∕m. Note that both the absolute value of spring constant ∣kb∣ and frequency-multiplied damping cb×ω exhibited U-shaped variation with lubricant bridge elongation; that is, those values decrease with bridge elongation and they begin to increase after reaching the minimum. The variation in the spring constant was found to be in good accordance with the quasi-static stiffness of the lubricant bridge, and variation in the damping coefficient was explained by energy loss arising in the vibrating lubricant bridge.

Download Full-text

Driving Force Testing of Lift Mechanism for Green Energy Furniture

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.201-203.2803 ◽

2011 ◽

Vol 201-203 ◽

pp. 2803-2806

Author(s):

Tien Li Chen ◽

Tsing Tshih Tsung ◽

Liang Yu Yang ◽

Ho Chang

Keyword(s):

Driving Force ◽

Testing Machine ◽

Green Energy ◽

Force Balance ◽

Key Technology ◽

Balance System ◽

Universal Testing ◽

Study Results ◽

Lift Mechanism ◽

Key Factor

The purpose of this study is testing the force of green energy lift mechanism and analyzes its result to get the key technology for green energy (saving force and energy). At first, the green energy lift mechanisms on the market are surveyed, then the mechanism are analyzed in this study. The force balance system of the mechanism is used to save force and energy. The position limitation of saving force and energy for the force balance system will be investigated. Universal testing machine is used to test the driving force by the different loads during the lift mechanism moving downward. The tested results of the driving force will be estimated. The study results show that the loads influence significantly the driving force. The angle between pulley and wire is the key factor of the driving force.

Download Full-text

Virtual Modelling and Testing of the Single and Contra-Rotating Co-Axial Propeller

Drones ◽

10.3390/drones4030042 ◽

2020 ◽

Vol 4 (3) ◽

pp. 42

Author(s):

Balram Panjwani ◽

Cecile Quinsard ◽

Dominik Gacia Przemysław ◽

Jostein Furseth

Keyword(s):

Experimental Data ◽

Experimental Testing ◽

Measurement Data ◽

Force Balance ◽

Virtual Model ◽

Balance System ◽

Thrust Measurement ◽

Lift And Drag ◽

Full Scale Tests ◽

Thrust And Torque

Propellers are a vital component to achieve successful and reliable operation of drones. However, the drone developer faces many challenges while selecting a propeller and a common approach is to perform static thrust measurement. However, the selection of a propeller using a static thrust measurement system is time-consuming. To overcome a need for the static thrust system a virtual model has been developed for measuring both the static and dynamic thrust of a single and coaxial propeller. The virtual model is reliable enough to minimize the need for full-scale tests. The virtual model has been built using two open-source software Qblade and OpenFoam. Qblade is employed to obtain the lift and drag coefficients of the propeller’s airfoil section. OpenFoam is utilized to perform the flow simulations of propellers and for obtaining the thrust and torque data of the propeller. The developed virtual model is validated with experimental data and the experimental data are obtained by developing a multi-force balance system for measuring thrusts and torques of a single and a pair of coaxial contra-rotating propellers. The data obtained from the propeller virtual model are compared with the measurement data. For a single propeller, the virtual model shows that the estimated forces are close to the experiment at lower rotational speeds. For coaxial propellers, there are some deviations at the rear propeller due to the turbulence and flow disturbance caused by the front propeller. However, the computed thrust data are still accurate enough to be used in selecting the propeller. The studies indicate that in the future, these virtual models will minimize a need for experimental testing.

Download Full-text

Performance Evaluation of an Aerodynamic Blade Model Using a Bottom-mounted Force Balance System

AIAA Propulsion and Energy 2019 Forum ◽

10.2514/6.2019-4160 ◽

2019 ◽

Cited By ~ 1

Author(s):

C.U. Ebuzeme ◽

Z.A. Quadri ◽

Olugbenga Noah ◽

Emmanuel O. Ogedengbe ◽

Charles Eguma

Keyword(s):

Performance Evaluation ◽

Force Balance ◽

Balance System ◽

Blade Model

Download Full-text

A new method for force prediction in an accelerometer force balance system using support vector regression

Transactions of the Institute of Measurement and Control ◽

10.1177/0142331219895645 ◽

2020 ◽

Vol 42 (4) ◽

pp. 880-889

Author(s):

Sushmita Deka ◽

Pallekonda Ramesh Babu ◽

Maneswar Rahang

Keyword(s):

Support Vector Regression ◽

Force Measurement ◽

Aerodynamic Force ◽

Accurate Prediction ◽

Force Balance ◽

Support Vector ◽

Inference System ◽

Force Prediction ◽

Balance System ◽

Testing Data

The accurate prediction of force is very important in the present scenario of aerodynamic force measurement. The high accuracy of force prediction during calibration facilitates a better accuracy of force measurement in aerodynamic facilities like shock tunnels and wind tunnels. The present study describes the force prediction in an accelerometer force balance system using support vector regression (SVR). The comparison of SVR with the existing force prediction techniques namely, adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) has also been carried out. The accelerometer force balance used in the current experimentation consists of a tri-axial accelerometer to measure the response on an aluminium hemispherical model on the application of force. The impulse forces were applied along the axial, normal and azimuthal directions. The forces were predicted using the accelerations obtained from the tri-axial accelerometer. SVR method was able to predict the forces quite accurately as compared to ANFIS and ANN. However, SVR has the advantage over ANFIS and ANN in that it is independent of the magnitude of the training and testing data. It is capable of an accurate prediction of forces with any magnitude of training and testing data, unlike ANFIS and ANN.

Download Full-text

Dynamic Calibration of Three-Component Accelerometer Force Balance System Using Deconvolution

Advances in Mechanical Engineering - Lecture Notes in Mechanical Engineering ◽

10.1007/978-981-15-0124-1_145 ◽

2020 ◽

pp. 1675-1683

Author(s):

Sushmita Deka ◽

Pallekonda Ramesh Babu ◽

Maneswar Rahang

Keyword(s):

Force Balance ◽

Dynamic Calibration ◽

Balance System

Download Full-text

Measurement of spring constant and damping coefficient of the ground

Journal of Terramechanics ◽

10.1016/0022-4898(84)90051-x ◽

1984 ◽

Vol 21 (3) ◽

pp. 303

Author(s):

Shojiro Hata ◽

Kazyyoshi Tateyama

Keyword(s):

Spring Constant ◽

Damping Coefficient

Download Full-text

An Aerodynamic Load Correction Method for HFFB Technique Based on Signal Decoupling and an Intelligent Optimization Algorithm

Shock and Vibration ◽

10.1155/2018/2128519 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12

Author(s):

Chengzhu Xie ◽

An Xu ◽

Ruohong Zhao

Keyword(s):

Optimization Problem ◽

Bending Moment ◽

Correction Method ◽

Force Balance ◽

Aerodynamic Load ◽

Independent Components ◽

Aerodynamic Damping ◽

Balance System ◽

Building Model ◽

Intelligent Optimization Algorithm

In high-frequency force balance (HFFB) wind tunnel tests, the aerodynamic wind loads at the base of the building model are usually amplified by the model-balance system. This paper proposes a new method for eliminating such an amplification effect. Firstly, the measured base bending moment signals are decoupled into independent components. Then, an optimization model is established to represent the problem of identifying the natural frequencies and damping ratios for the different modes of the model-balance system. Finally, the genetic algorithm (GA) is employed to seek the solution to the optimization problem, and the base bending moment is corrected through the identified dynamic parameters of the model-balance system. Compared to the conventionally used knocking method, the proposed method requires no extra knocking tests and can take the aerodynamic damping of the model-balance system into account. An engineering case, the Guangzhou East Tower (GZET), is taken as an example to show the effectiveness of the method.

Download Full-text