scholarly journals Speed Fluctuation Suppression Based on an Adaptive Periodic Disturbance Observer for an Inverter Compressor

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5014
Author(s):  
Fankun Meng ◽  
Zhengguo Li ◽  
Xiaoli Sun ◽  
Xiaoqin Wen ◽  
Michael Negnevitsky ◽  
...  
Keyword(s):  
Disturbance Observer ◽  
High Efficiency ◽  
Low Frequency ◽  
Notch Filter ◽  
Fundamental Wave ◽  
Matlab Simulation ◽  
Frequency Range ◽  
Periodic Disturbance ◽  
Adaptive Notch Filter ◽  
Speed Fluctuation

Repetitive operations have been extensively used in the inverter compressor refrigeration industry. The approximately periodic disturbance caused by repetitive operations must be compensated to realize stable and high-efficiency operation. In this paper, a periodic disturbance observer (PDOB) is proposed to tackle the speed fluctuation of an inverter compressor in the low-frequency range. Periodic disturbance, consisting of a fundamental wave and corresponding harmonics, can thus be estimated and compensated; in addition, sensitivity and complementary sensitivity can reach a compromise through the use of a certain parameter. Aiming at a different operation environment, an adaptive notch filter based on the Steiglitz–McBride method is employed to estimate the fundamental frequency of periodic disturbance. Finally, the feasibility of our approach is verified by MATLAB simulation, and experiments are implemented to illustrate that speed fluctuation can be more effectively attenuated by the proposed method in comparison with general DOB.

scholarly journals Detection and Reduction of Middle-Frequency Resonance for Industrial Servo with Self-Tuning Lowpass Filter

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Wen-Yu Wang ◽  
An-Wen Shen
Keyword(s):  
Notch Filter ◽  
Corner Frequency ◽  
Frequency Range ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Frequency Resonance ◽  
Adaptive Notch Filter ◽  
Frequency Detection ◽  
Self Tuning ◽  
The Difference

A novel method for middle frequency resonance detection and reduction is proposed for speed control in industrial servo systems. Defects of traditional resonance reduction method based on adaptive notch filter in middle frequency range are analyzed. And the main reason is summarized as the difference between the resonance frequency and the oscillation frequency. A self-tuning low-pass filter is introduced in the speed feedback path, whose corner frequency is determined by FFT results and several self-tuning rules. With the proposed method the effective range of the adaptive filter is extended across the middle frequency range. Simulation and Experiment results show that the frequency detection is accurate and resonances during the speed steady states and dynamics are successfully reduced.

Research on the Signal Encrypted by Unary Polynomial Transformation Chaos

2013 ◽  
Vol 846-847 ◽  
pp. 952-955
Author(s):  
Ling Wu ◽  
Hong Chen ◽  
Shu Bin Gu ◽  
Lian Dong Lin ◽  
Guo Qiang Lan
Keyword(s):  
Time Domain ◽  
Low Frequency ◽  
Chaotic Signal ◽  
Frequency Region ◽  
Simulation Environment ◽  
Matlab Simulation ◽  
Frequency Range ◽  
Frequency Signal ◽  
Polynomial Transformation ◽  
Narrow Area

In terms of the chaotic signal needed by encryption, it is the more complicate the better. In addition, the frequency range of chaos should be wider than that of signal to be encrypted. However, chaotic spectrum usually is a narrow area in the low frequency region, and the complexity is not high enough. The signals encryption effects are affected. In order to solve this problem, this paper used the chaos transformed by unary polynomial to encrypt signals. Under the Matlab simulation environment, it is confirmed from time-domain and frequency-domain perspectives that the encryption effect of transformed chaos is better. Even the higher frequency signal can also be covered up completely. At the same time, the difficulty of decoding the encrypted signals is greatly increased, and the anti-attacking capability is strengthened.

Unknown Multiple Narrow-Band Disturbance Rejection in Hard Disk Drives: An Adaptive Notch Filter and Perfect Disturbance Observer Approach

2010 ◽  
Author(s):  
Xu Chen ◽  
Masayoshi Tomizuka
Keyword(s):  
Disturbance Observer ◽  
Narrow Band ◽  
Hard Disk Drives ◽  
Notch Filter ◽  
Hard Disk ◽  
Disk Drive ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Adaptive Notch Filter ◽  
Control Scheme

In this paper, an adaptive control scheme is developed to reject unknown multiple narrow-band disturbances in a hard disk drive. An adaptive notch filter is developed to efficiently estimate the frequencies of the disturbance. Based on the correctly estimated parameters, a disturbance observer with a newly designed multiple band-pass filter is constructed to achieve asymptotic perfect rejection of the disturbance. Evaluation of the control scheme is performed on a benchmark problem for HDD track following.

Adaptive aeroservoelastic mode stabilization of flexible airbreathing hypersonic vehicle

2019 ◽  
Vol 25 (15) ◽  
pp. 2124-2142
Author(s):  
Minnan Piao ◽  
Youan Zhang ◽  
Mingwei Sun ◽  
Zhihong Yang ◽  
Zenghui Wang ◽  
...  
Keyword(s):  
Flight Control ◽  
Vibration Suppression ◽  
Controller Design ◽  
Low Frequency ◽  
Notch Filter ◽  
Hypersonic Vehicle ◽  
Adaptive Notch Filter ◽  
Disturbance Rejection Control ◽  
High Bandwidth ◽  
Mode Stabilization

The statically unstable airbreathing hypersonic vehicle requires a high-bandwidth controller to control the instability, which results in intricate interactions among the aerodynamics, the low-frequency structural modes, and the flight control system. Especially, the structural frequencies are uncertain and time-varying, which further raises the difficulty of controller design. In this paper, two adaptive aeroservoelastic mode stabilization methods are proposed. First, the condition of phase stabilization is given under the linear active disturbance rejection control framework to realize the self-stabilization of the flexible modes. Then, an adaptive notch filter, which employs the lattice type structure and the fast-recursive square root algorithm, is presented. Both methods can achieve the adaptive vibration suppression and extend the control bandwidth. Simulation results demonstrate the effectiveness of the proposed approach.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Dynamic Damping and Stiffness Characteristics of the Rolling Tire

2001 ◽  
Vol 29 (4) ◽  
pp. 258-268 ◽  
Author(s):  
G. Jianmin ◽  
R. Gall ◽  
W. Zuomin
Keyword(s):  
Dynamic Behavior ◽  
Variable Parameter ◽  
Low Frequency ◽  
Vertical Load ◽  
Frequency Range ◽  
Inflation Pressure ◽  
Vehicle Simulation ◽  
Dynamic Damping ◽  
Speed Range ◽  
Stiffness Characteristics

Abstract A variable parameter model to study dynamic tire responses is presented. A modified device to measure terrain roughness is used to measure dynamic damping and stiffness characteristics of rolling tires. The device was used to examine the dynamic behavior of a tire in the speed range from 0 to 10 km/h. The inflation pressure during the tests was adjusted to 160, 240, and 320 kPa. The vertical load was 5.2 kN. The results indicate that the damping and stiffness decrease with velocity. Regression formulas for the non-linear experimental damping and stiffness are obtained. These results can be used as input parameters for vehicle simulation to evaluate the vehicle's driving and comfort performance in the medium-low frequency range (0–100 Hz). This way it can be important for tire design and the forecasting of the dynamic behavior of tires.

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