Leakage is the most important failure mode in aircraft hydraulic systems caused by wear and tear between friction pairs of components. The accurate detection of abrasive debris can reveal the wear ...condition and predict a system's lifespan. The radial magnetic field (RMF)-based debris detection method provides an online solution for monitoring the wear condition intuitively, which potentially enables a more accurate diagnosis and prognosis on the aviation hydraulic system's ongoing failures. To address the serious mixing of pipe abrasive debris, this paper focuses on the superimposed abrasive debris separation of an RMF abrasive sensor based on the degenerate unmixing estimation technique. Through accurately separating and calculating the morphology and amount of the abrasive debris, the RMF-based abrasive sensor can provide the system with wear trend and sizes estimation of the wear particles. A well-designed experiment was conducted and the result shows that the proposed method can effectively separate the mixed debris and give an accurate count of the debris based on RMF abrasive sensor detection.
A miniature single-piston valve flow-matching water-hydraulic pump is described in this paper, which designs with a unique double-face cam mechanism to achieve the reciprocating motion of the piston ...and a new flow-matching valve to adapt to the requirements of the frequency of flow-matching, and the use of a brushless DC motor to regulate the speed and control the flow of the pump. In this paper, the mechanical structure and working principle of this new type of water-hydraulic pump are described, the mathematical model of the valve flow distribution process is established, the transfer functions of the suction and drain process are obtained, and the relationship between the structural parameters of the distribution valve and the transient output characteristics of this type of water-hydraulic pump is simulated, and the simulation results show that the quality of the valve spool is the key factor affecting the switching speed of the distribution valve. The transient pressure and transient flow rate of the pump are studied experimentally, which reveals the pulsation law of the output characteristics of this single-piston pump, and lays a theoretical foundation for the design of a double-piston pulsation-free hydraulic pump.
The hydraulic pump provides a pressurized flow to drive the hydraulic system. It often works under harsh conditions, so it is necessary to monitor its condition for the smooth operation of the ...hydraulic system. However, in practical situations, it is quite difficult to identify incipient faults. In this article, a modification to the particle swarm optimization (PSO) technique is proposed to forecast small changes in the hydraulic pump parameters during fault. One of the most important applications of this study is in aviation where an incipient fault in the hydraulic pump can produce terrible consequences as it controls aileron, elevator, and rudder actuation. The modification is applied to the adaptive inertia weighted PSO by using a constriction coefficient that contains the explosion of swarms. The exploitation and exploration tradeoff of the PSO with the constriction coefficient has been discussed and demonstrated. This research also investigates whether the altered PSO parameters guarantee convergence as well as order-1 and order-2 stability using an existing convergence criterion. Finally, its validity has been confirmed by performing several simulations on the standard objective function utilized in fault identification applications.
Hydraulic pumps are a positive displacement pump whose working principle causes inherent output flow pulsation. Flow pulsation produces pressure pulsation when encountering liquid resistance. ...Pressure pulsation spreads in the pipeline and causes vibration, noise, damage, and even pipeline rupture and major safety accidents. With the development of airborne hydraulic systems with high pressure, power, and flow rate, the hazards of vibration and noise caused by pressure pulsation are also amplified, severely restricting the application and development of hydraulic systems. In this review paper, the mechanism, harm, and suppression method of pressure pulsation in hydraulic systems are analyzed. Then, the classification and characteristics of pulsation attenuators according to different working principles are described. Furthermore, the critical technology of simulation design, matching method with airborne piston pumps, and preliminary design method of pulsation attenuators are proposed. Finally, the development trend of pulsation attenuators is prospected. This paper provides a reference for the research and application of pressure pulsation attenuators.
The first European settlements in the new world faced technical issues with the help of the XVI century scientific advances. Besides briefly exposing the scientific and technological situation, this ...paper explores, with the help of reverse engineering, two singular mechanical wits representative of the technological advances introduced in America to overcome different problems. Firstly, a pump, based on an alternative movement system through crankshafts and pistons used against the continuous flooding suffered in the Ciudad de México valley. Although flooding remained a problem (it was solved in the XX century), hydraulic pumps were essential for continuous soil drainage. Secondly, a port crane for handling cannons, military devices, and construction materials during the Lima fortification in the XVII century. For both cases, reverse engineering, through engineering methods, Computer-Aided Design CAD programs, and additive manufacturing, provides virtual and/or tangible mockups that help to analyze and improve our knowledge about the dimensions, materials, and functions of used (and currently lost) mechanical systems during the American colonization.
Recognizing the crucial role that transport and lifting installations play in various sectors, including industry, construction, and extraction, as well as in mechanizing loading and unloading ...operations, and the movement of equipment or materials, special attention must be oriented to the diversification and the production of these installations by using the most advanced technologies. The paper presents some operating principles and characteristics of a lifting and transport Spider Crane installation equipment. This installation is considered a more economical and efficient alternative to traditional cranes for works where lifting requirements are below certain limits and significant height. Thus, an analysis of the hydraulic lifting system was carried out, based on the calculation of hydraulic fluid flows for the drive pumps. Also, was evaluated the specific speeds and forces of the hydraulic cylinders, a mechanical analysis of the clamping system with hook, as well as a finite element analysis of some mechanical and hydraulic components.
Piezo-actuators can produce higher force and can be operated at higher actuation frequencies. However, the displacement range is limited to 0.1% of the actuator length. Piezo-hydraulic pumps ...developed using such piezo-actuators has to be operated at higher actuation frequencies to deliver higher pump flowrate. This limits the application of such piezo pumps for pumping higher viscosity fluids at higher flowrate. Thus, it is necessary to increase the displacement of piezo-actuators by different amplification mechanisms compromising with its maximum force handling capacity. Literature shows different piezo-actuator based piezo-hydraulic pumps, but piezo-hydraulic pump using flexurally amplified piezoelectric actuator is least reported anywhere. Hence, this work aims at development of a flexurally amplified piezoelectric actuator (FAPA) based piezo-hydraulic pump. The design of piezo-hydraulic pump consists of FAPA376 as pumping actuator and the pumping chamber is made from stainless steel metallic bellows. The inlet and outlet ports coming out from pumping chamber are connected with two unidirectional valves to avoid back flow of the fluid. The pumping actuator FAPA376 produces a maximum displacement of 376 µm when applied with its rated voltage signal of 150 V and hence by the name FAPA376. Suitable mathematical model for piezo-hydraulic pump is developed using MATLAB/Simulink software and simulations are carried out to determine pumping displacement and flowrate of the piezo-hydraulic pump. Simulation resulted with pumping peak displacement of 375.5 µm, hysteresis of 27.17 µm and flowrate of 25.55 mL/min at 1 Hz actuation frequency. Experiments are performed on developed piezo-hydraulic pump at different actuation frequencies to determine its pumping displacement and flow rate. Experiments carried out on the piezo-hydraulic pump at 1 Hz actuation frequency resulted with pumping peak displacement of 369 µm, hysteresis of 16.22 µm and flowrate of 25.36 mL/min. The simulated and experimental flowrate of piezo-hydraulic pump are in good agreement with each other having an error of 0.75% at 1 Hz.
Aiming at fault feature extraction of a hydraulic pump signal, a new method based on symplectic geometry mode decomposition (SGMD) and power spectral entropy (PSE) is proposed. First, the SGMD is ...applied to decompose a multi-component fault signal, then the
symplectic geometry components (SGCs) can be obtained. Second, the
SGCs are reconstructed as a signal of interest and, consequently, the power spectral entropy of each constructed signal is computed to quantify the complexity and uncertainty of their spectra. Finally, the difference value (D-value) between the adjacent entropies is used as a SGCs criterion, whose turning point indicates the most information of reconstructed signal. Hydraulic pump signals are tested and verified, and results demonstrate that the proposed method can extract the richest fault feature information of hydraulic pump signals effectively.
The normal operation of the hydraulic pump is the significant premise for the stable and dependable working of hydraulic equipment. Consequently, this research comes up with a health condition ...detection method of hydraulic pump. First of all, this approach selects resonance-based sparse signal decomposition (RSDD) to adaptively disintegrate vibration signals. The biggest problem of the RSDD algorithm is the requirement to artificially set a large number of key parameters, such as quality factor Q, weight coefficient A, and Lagrange operator u. The improper parameter settings will seriously affect the decomposition performance. To overcome this shortcoming, an enhanced whale optimization algorithm is presented to search the best parameter combination of the RSDD. The algorithm takes the correlation kurtosis as the optimization objective function to adaptively disintegrate the signal into low and high resonance components. Moreover, on the basis of the modified analytic hierarchy process and the amplitude-aware permutation entropy, the modified hierarchical amplitude-aware permutation entropy is raised for measuring the complexity of the measured time series more accurately and comprehensively. After that, a health condition detection method for hydraulic pump based on enhanced whale optimization-resonance-based sparse signal decomposition and modified hierarchical amplitude-aware permutation entropy is raised. Finally, through the usage of the hydraulic pump vibration data, this method is compared with other approaches. According to the experimental results, the raised method can identify the fault type more effectively, which is capable of offering a feasible idea for the health condition detection of hydraulic equipment.
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