Papers by Keyword: Low-Pass Filter (LPF)

Abstract: Multi-period repetitive controllers improve the disturbance attenuation characteristic of themodified repetitive control system that follows the periodic reference input with small steady stateerror. Recently, the parameterization of all stabilizing multi-period repetitive controllers was studied.However, when the parameterization of all stabilizing multi-period repetitive controllers is used, theinput-output characteristic and the feedback characteristic cannot be specified separately. From thepractical point of view, it is desirable to specify the input-output characteristic and the feedback characteristicseparately. In addition, the parameterization is useful to design stabilizing controllers. Fromthis view-point, the parameterization of all stabilizing two-degree-of-freedom multi-period repetitivecontrollers those can specify the input-output characteristic and the disturbance attenuation characteristicseparately was solved by Yamada et al. However, when we design a stabilizing two-degree-offreedommulti-period repetitive controllers using the parameterization proposed by Yamada et al, thefrequency characteristic of the control system cannot be settled so easily. From the practical point ofview, the frequency characteristic of the control systems are required to be easily settled. This problemcan be solved by obtaining the parameterization of all stabilizing two-degree-of-freedom multi-periodrepetitive controllers with the specified frequency characteristic. In this paper, we propose the parameterizationof all stabilizing two-degree-of-freedom multi-period repetitive controllers with thespecified frequency characteristic.

Abstract: To determine fatigue life of Loader transmission and to analyze machine power for different user, the torque loads of wheel loader transmission are tested and calibrated with the method of four sections per cycle. The disturbed signals are filtered by low-passed filter, and anomalous spikes are eliminated with the NSOFT. And contrastively analyzes the disposal effect of signal, then acquires pure random load-time course. It concludes that one Hz of the low-pass filter frequency is suitable, and the test signal is in line with the actual work of Loader. These provide the base for getting load spectrum and virtual test on wheel loader transmission.

Abstract: In order to reduce the error of the phase lock-loop (PLL) and compensate the delay of the low pass filter on harmonics detection, In the paper, a detecting-method without PLL in single-phase circuit is researched. In this method, the PLL and LPF are omitted, the feedback and average theory are used, so that the problem of detecting accuracy induced by PLL and real-time induced by LPF is solved. It is testified through comparison, analysis and simulation, that both methods can reduce the latency, improve dynamic response speed, the feedback method can reduce the delay in a dynamic, continuous process, while the average theoretical method can reduce the delay quantitatively.

Abstract: In order to solve the problem of integration saturation drift and hardship in compensation quantity calculation exist in rotor flux observation of induction motor, a rotor flux observer based on nonlinear quadrature double compensation method is presented in this paper. The quantity of compensation is determined dynamically according to the quadrature level between flux and back electromotive force. Through the order change of compensation and low-pass filter, quick response of flux when signal frequency leaps is realized. The simulation result shows that the method can improve the flux waveform, realize the accurate and swift track of flux.

Abstract: In this paper, we develop a transpire freight impact test system based on ASTM D6537 standard. Test object is the transportation packaging of the laptop computer in the process of drop impact test. Data acquisition are handled using low-pass filter via Matlab software, which calculated four test indicators that consist of peak acceleration, the filtered acceleration, velocity change and pulse duration. We use several drop ways, which the drop height is 40cm and 70cm, respectively. Experiments show that the test object can protect the product safety when drop height is 70cm, but the box will be broken.

Abstract: Anti-aliasing filter is widely used in the field of communication and the information collecting system. Generally, anti-aliasing filter is consisted with a low-pass filter, which possesses rapid roll-off rate. In order to ensure that there will be a very smooth amplitude frequency characteristic, the high order Butterworth low-pass filter is adopted to work as anti-aliasing filter. As we know, to design this kind of high order low-pass filter will involve large amount of manual calculation. In order to reduce the manual calculation job, which is meaningless and reduplicated, in this paper, a MATLAB scripts is proposed to establish a model of computer aided design for anti-aliasing filter. To use this MATLAB scripts, the value of parameter for the filter can be easily got according to the design specification.

Abstract: High-g accelerometer and storage test system is designed for the measurement of multi-layer steel targets penetration. The penetration test of the double layer steel target is performed, and the verload acceleration is obtained when the projectile penetrates the steel target. According to the overload data, the effective overload accelerations are concluded. The effective overload accelerations gained when projectile penetrates the double steel targes are 81078g and 152061g respectively. Also from the calculation, it can be concluded that the test errors are all less than 10%, which can meet the requirement of penetrating multi-layer steel targets.

Abstract: In this paper, according to the base-adaptive detecting method of harmonic current for APF, there had contradiction between detecting accuracy and dynamic response. It had been proved that this system is a symmetrical notch-filter. Based on analysis above, this paper is proposed improved-adaptive detecting method. A low-pass filter has been in base-adaptive system. We first discussed the stability of improved system. Then theoretical analysis and simulation test shows the bandwidth had been reduced nearby reference frequency. Simulation had showed that the dynamic performance was in a period and the harmonic distortion rate was no more than 1.7%.

Abstract: This paper presents a comparison work between the filtering methods of fatigue strain loadings using the frequency spectrum and the wavelet transform (WT), in which a raw loading signal can be simplified for purpose of simulation. For this reason, the Fast Fourier Transform (FFT) and the Morlet wavelet algorithms were used in order to transform the vibrational fatigue time series into the frequency domain signal, leading to the observation of the frequency characteristics of the signal. To retain high amplitude cycles in the FFT algorithm, a low pass filter technique was applied to remove the high frequency signals with small amplitude that are non-damaging. The departure of high frequency information smoothed the low amplitude cycles at high frequency events in the fatigue signal. The Butterworth filter was selected as the most efficient filter design as it retained most of the fatigue damage and also had the capability to remove 30 % of the original low amplitude cycles. On the other hand, the Morlet wavelet managed to remove 64 % of the original 59 second signal. This wavelet filtering method removed 34 % more than the similar procedure applied through the FFT approach. Hence, this fatigue data summarising algorithm can be used for studying the durability characteristics of automotive components.

Abstract: Multi-period repetitive controllers improve the disturbance attenuation characteristic of the modified repetitive control system that follows the periodic reference input with a small steady state error. Recently, the parameterization of all stabilizing multi-period repetitive controllers was studied. However, when the parameterization of all stabilizing multi-period repetitive controllers is used, the input-output characteristic and the feedback characteristic cannot be specified separately. From the practical point of view, it is desirable to specify the input-output characteristic and the feedback characteristic separately. In addition, the parameterization is useful to design stabilizing controllers. Therefore, the problem of obtaining the parameterization of all stabilizing two-degree-of-freedom multi-period repetitive controllers that can specify the input-output characteristic and the disturbance attenuation characteristic separately is important to solve. In this paper, we propose the parameterization of all stabilizing two-degree-of-freedom multi-period repetitive controllers.