Active Compensation of Lightly Damped Electrohydraulic Cylinder Drives Using Derivative Signals

1969 ◽  
Vol 184 (1) ◽  
pp. 83-98 ◽  
Author(s):  
R. Bell ◽  
A. De Pennington
Keyword(s):  
Dynamic Response ◽  
Pressure Transducer ◽  
System Analysis ◽  
Active Damping ◽  
Active Compensation ◽  
Minor Loop ◽  
Mechanical Damping ◽  
Linearized Model ◽  
Load Mass ◽  
Friction Bearings

The dynamic response of a cylinder drive is considerably influenced by the mechanical damping at the load. This paper discusses the use of acceleration and pressure transducer signals to introduce active damping into drives where the load mass is supported on anti-friction bearings, i.e. where the inherent mechanical damping is a minimum. The analysis is based on the use of a linearized model. The significance of the model and the system analysis is substantiated by the results of experiments carried out to assess the merits of these forms of minor loop compensation.

scholarly journals Investigation of X and Y Configuration Modal and Dynamic Response to Velocity Excitation of the Nanometer Resolution Linear Servo Motor Stage with Quasi-Industrial Guiding System in Quasi-Stable State

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 951
Author(s):  
Artur Piščalov ◽  
Edgaras Urbonas ◽  
Darius Vainorius ◽  
Jonas Matijošius ◽  
Artūras Kilikevičius
Keyword(s):  
Dynamic Response ◽  
System Analysis ◽  
Operating Time ◽  
Stable State ◽  
Degree Of Freedom ◽  
Diagnostic Tools ◽  
Nanometer Scale ◽  
Positioning Systems ◽  
Industrial Enterprises ◽  
Guiding System

Research institutions and industrial enterprises demand high accuracy and precision positioning systems to fulfil cutting edge requirements of up-to-date technological processes in the field of metrology and optical fabrication. Linear motor system design with high performance mechanical guiding system and optical encoder ensures nanometer scale precision and constant static error, which can be calibrated by optical instruments. Mechanical guiding systems has its benefits in case of control theory and its stability; unfortunately, on the other hand, there exists high influence of structure geometry and tribological effects such as friction and modal response. The aforementioned effect cannot be straightforwardly identified during the assembly process. Degradation of dynamic units can be detected only after certain operating time. Single degree of freedom systems are well investigated and the effect of degradation can be predicted, but there exists a gap in the analysis of nanometer scale multi degree of freedom dynamic systems; therefore, novel diagnostic tools need to be proposed. In this particular paper, dual axes dynamic system analysis will be presented. The main idea is to decouple standard stacked XY stage and analyse X and Y configuration as two different configurations of the same object, while imitators of corresponding axes are absolutely solid and stationary. As storage and analysis of time domain data is not efficient, main attention will be concentrated on frequency domain data, while, of course, statistical and graphical representation of dynamic response will be presented. Transfer function, dynamic response, spectral analysis of dynamic response, and modal analysis will be presented and discussed. Based on the collected data and its analysis, comparison of X and Y responses to different velocity excitation will be presented. Finally, conclusions and recommendations of novel diagnostic way will be presented.

Dynamic characterisation of pressure transducers using shock tube methods

2019 ◽  
Vol 42 (4) ◽  
pp. 743-748
Author(s):  
Andy J Knott ◽  
Ian A Robinson
Keyword(s):  
Dynamic Response ◽  
Shock Tube ◽  
Significant Variation ◽  
Pressure Transducer ◽  
Ideal Gas ◽  
Pressure Transducers ◽  
Pressure Step ◽  
Instantaneous Pressure

This paper describes the characterisation of the dynamic response of a range of pressure transducer systems. The transducers were subjected to virtually instantaneous pressure step inputs in the National Physical Laboratory’s shock tube facilities. The magnitudes of these pressure steps were derived from ideal gas theory, with prior commissioning tests having been performed to demonstrate the theory’s validity in this application. The results demonstrate a significant variation in response obtained from various combinations of transducer, instrumentation settings, and mounting arrangement.

Study on Dynamic Response of Piping System Induced by Waterhammer Considering Support Characteristics

2017 ◽  
Author(s):  
Atsushi Okami ◽  
Shunji Kataoka ◽  
Takuro Honda
Keyword(s):  
Dynamic Response ◽  
System Analysis ◽  
Sliding Friction ◽  
Dynamic Effect ◽  
Response Spectra ◽  
Load Factor ◽  
Plastic Behavior ◽  
Piping System ◽  
Transient Load ◽  
Effect Of The Support

Waterhammer is the phenomenon which occurs due to rapid valve operation or sudden stop of pumps. When the waterhammer occurs, unbalanced pressure between elbows causes transient load on piping system. In the piping design against the waterhammer, it is necessary to evaluate the strength and the displacement of piping system against the transient load, and required to provide adequate piping supports. In the piping design, dynamic analysis and static analysis with DLF (Dynamic Load Factor) are often conducted to consider dynamic effect of the water hammer load. The piping support often regarded as rigid in the piping system analysis, however, because of support characteristic (flexibility, plastic behavior, sliding friction), the dynamic response of piping system changes from analysis result with rigid support. For this reason, support characteristics shall be considered adequately. Nevertheless, effect of the support characteristics on the piping design has not been discussed sufficiently. In this paper, to clarify the effect of the support characteristics against the waterhammer load, a series of the nonlinear dynamic analyses were conducted. Based on the analysis results, the response spectra and the ductility charts considering the nonlinearities of the piping system were created. the design approach to properly control the displacement of piping system based on the nonlinear response spectra and ductility charts, is proposed, and the dynamic response against waterhammer load in the piping system of LNG loading line is discussed.

Correcting for Response Lag in Unsteady Pressure Measurements in Water

1993 ◽  
Vol 115 (4) ◽  
pp. 676-679 ◽  
Author(s):  
Rand N. Conger ◽  
B. R. Ramaprian
Keyword(s):  
Dynamic Response ◽  
Pressure Transducer ◽  
Water Channel ◽  
Inadequate Response ◽  
Pressure Measurements ◽  
Pressure Transducers ◽  
Pitching Airfoil ◽  
Unsteady Pressure ◽  
Unsteady Pressure Measurements ◽  
Type Pressure

There is not much information available on the use of diaphragm-type pressure transducers for the measurement of unsteady pressures in liquids. A procedure for measuring the dynamic response of a pressure transducer in such applications and correcting for its inadequate response is discussed in this report. An example of the successful use of this method to determine unsteady surface pressures on a pitching airfoil in a water channel is presented.

An Enhanced Fuel Cell Dynamic Model With Electrochemical Phenomena Parameterization as Test Bed for Control System Analysis

2019 ◽  
Vol 16 (3) ◽  
Author(s):  
Victor M. Fontalvo ◽  
George J. Nelson ◽  
Humberto A. Gomez ◽  
Marco E. Sanjuan
Keyword(s):  
Control System ◽  
Fuel Cell ◽  
Dynamic Response ◽  
Proton Exchange Membrane ◽  
System Analysis ◽  
Control Strategies ◽  
Dynamic Performance ◽  
Proton Exchange ◽  
Test Bed

In this work, a model of a proton exchange membrane fuel cell (PEMFC) is presented. A dynamic performance characterization is performed to assess the cell transient response to input variables. The model used in the simulation considers three different phenomena: mass transfer, thermodynamics, and electrochemistry. The main sources of voltage loss are presented: activation, electrical resistance, and concentration. The model is constructed to avoid the use of fitted parameters, reducing the experimentation required for its validation. Hence, the electrochemical model is parameterized by physical variables, including material properties and geometrical characteristics. The model is demonstrated as a test-bed for PEMFC control system design and evaluation. Results demonstrate that the steady-state and dynamic behavior of the system are represented accurately. A case study is included to show the functionality of the model. In the case study, the effect of the purge valves at the fuel cell discharges is analyzed under different scenarios. Regular purges of the cathode and the anode are shown to achieve a good performance in the system avoiding reactant starvation in the cell. A closed-loop dynamic response is included as an example of the model capabilities for the design of fuel cell control strategies. Two variables were selected to be controlled: voltage and pressure difference across the membrane. A multivariate control strategy was tested and its dynamic response was analyzed. It was found that there was a strong interaction between the control loops, making the control of the system a challenge.

USING INPUT INVARIANCE AS A METHOD TO FACILITATE SYSTEM DESIGN IN DPS APPLICATIONS

2004 ◽  
Vol 13 (04) ◽  
pp. 707-723 ◽  
Author(s):  
TEUVO SUNTIO ◽  
KONSTANTIN KOSTOV ◽  
TAUNO TEPSA ◽  
JORMA KYYRÄ
Keyword(s):  
Integrated Circuits ◽  
System Analysis ◽  
Noise Suppression ◽  
International Standards ◽  
Supply Side ◽  
Loop Gain ◽  
System Architectures ◽  
Minor Loop ◽  
Emi Filters ◽  
The Stability

Distributed power supply (DPS) systems are extensively used to supply different electronic equipment and systems such as telecom switching systems. Continuous reduction of supply voltages of digital integrated circuits from the previous industry standard of 5 V down to 1 V or even less has necessitated the use of point-of-load system architectures due to high supply currents. The input currents of the switched-mode power supplies contain typically high ripple currents necessitating the use of noise suppression (EMI) filters to meet the stringent requirements stipulated by international standards. The interactions between the load converters, EMI filters, and supply side converters may adversely affect the stability and performance of the system. The system analysis is typically made based on the behavior of the ratio between the output impedance of the supply side and the input impedance of the load side known as minor-loop gain. Certain forbidden regions in the complex plane have been developed out of which the minor-loop gain should stay in order to guarantee stability. Even if the restrictions for the behavior of the minor-loop gain are well-defined, the accurate prediction of the associated impedances is difficult or even impossible. We propose, in this paper, a method based on input invariance to cancel the load-side interactions in the small-signal sense. The only concern left is then the stability of EMI filters, which may be considered based on the input power of the associated converters.

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