Response Characteristics of a Pulse-Width-Modulated Electrohydraulic Servo

1970 ◽  
Vol 92 (2) ◽  
pp. 204-214 ◽  
Author(s):  
S. C. Tsai ◽  
P. R. Ukrainetz
Keyword(s):  
Pulse Width ◽  
Closed Loop ◽  
Mechanical Load ◽  
Transfer Characteristic ◽  
Double Fourier Series ◽  
Hydraulic Control ◽  
Pulse Width Modulated ◽  
Response Characteristics ◽  
Theoretical Analyses

Methods for analyzing the response characteristics of a pulse-width-modulated electro-hydraulic servomechanism are presented. Except for the modulator, the hydraulic control system is of conventional configuration. The modulator transfer characteristic is derived from a double Fourier series analysis of the pulse-width-modulated signal and this indicates the effect of the modulation parameters on the system performance. The valve flow which controls the mechanical load motion has been shown to be the dominant nonlinearity in a valve-controlled hydraulic system, and the system becomes more complicated due to the valve spool dither which is a consequence of the pulse-width-modulated signal. A dual-input describing function is developed for the equivalent valve flow gain in the determination of the system closed-loop frequency response. A numerical simulation is used to obtain the closed-loop transient response. Experimental verification of the theoretical analyses is carried out on a practical system. Good agreement is obtained between the predicted and the experimental responses.

Interpreting Open- and Closed-Loop Transfer Relations Between Cardiorespiratory Parameters: Lessons Learned from a Computer Model of Beat-to-Beat Cardiovascular Regulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 237-240
Author(s):  
P. Hammer ◽  
D. Litvack ◽  
J. P. Saul
Keyword(s):  
Computer Model ◽  
Closed Loop ◽  
Computer Models ◽  
Cardiovascular Regulation ◽  
Cardiovascular Control ◽  
Lessons Learned ◽  
Multiple Systems ◽  
Response Characteristics ◽  
Similarities And Differences

Abstract:A computer model of cardiovascular control has been developed based on the response characteristics of cardiovascular control components derived from experiments in animals and humans. Results from the model were compared to those obtained experimentally in humans, and the similarities and differences were used to identify both the strengths and inadequacies of the concepts used to form the model. Findings were confirmatory of some concepts but contrary to some which are firmly held in the literature, indicating that understanding the complexity of cardiovascular control probably requires a combination of experiments and computer models which integrate multiple systems and allow for determination of sufficiency and necessity.

Comparison of Iron Losses in Multiple Grain Size Iron Laminations under Sinusoidal and SPWM Excitation

2010 ◽  
Vol 670 ◽  
pp. 74-81 ◽  
Author(s):  
P. Rovolis ◽  
Antonios G. Kladas ◽  
J. Tegopoulos
Keyword(s):  
Grain Size ◽  
Flux Density ◽  
Fundamental Frequency ◽  
Pulse Width ◽  
Switching Frequency ◽  
Pulse Width Modulated ◽  
Iron Losses ◽  
Data Acquisition Card ◽  
Sinusoidal Excitation

The paper presents a methodology for determination of harmonic iron losses in laminated iron cores under both sinusoidal and sinusoidal pulse width modulated voltage excitations (SPWM) excitation for various frequencies. The method is based on measurements performed by using a convenient Epstein device supplied by a sinusoidal and a SPWM source, which are stored and processed in a PC by using an appropriate data acquisition card. It is shown that the switching frequency does not considerably affect iron losses under SPWM supply and vary non-linearly with flux density with respect to the ones measured under sinusoidal excitation for the same fundamental frequency.

Pulse-Width Modulated Amplifier for DC Servo System and Its Matlab Simulation

2015 ◽  
Vol 9 (1) ◽  
pp. 625-631
Author(s):  
Ma Xiaocheng ◽  
Zhang Haotian ◽  
Cheng Yiqing ◽  
Zhu Lina ◽  
Wu Dan
Keyword(s):  
Mathematical Model ◽  
Transfer Function ◽  
Input Signal ◽  
Pulse Width ◽  
Rotation Speed ◽  
Servo Motor ◽  
Matlab Simulation ◽  
Pulse Width Modulated ◽  
Signal Changes ◽  
The Relationship

This paper introduces a mathematical model for Pulse-Width Modulated Amplifier for DC Servo Motor. The relationship between pulse-width modulated (PWM) signal and reference rotation speed is specified, and a general model of motor represented by transfer function is also put forward. When the input signal changes, the rotation speed of the servo motor will change accordingly. By changing zeros and poles, transient performance of this system is discussed in detail, and optimal ranges of the parameters is recommended at the end of discussion.

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