mass system
Recently Published Documents


TOTAL DOCUMENTS

1010
(FIVE YEARS 182)

H-INDEX

36
(FIVE YEARS 5)

2022 ◽  
Author(s):  
Mingkun Pang ◽  
Tianjun Zhang ◽  
Rongtao Liu ◽  
Haotian Wang

Abstract Particle loss is the root cause for the occurrence of Karst Collapse Pillars (KCP) sudden water events. The pore adjustment of KCP filler will further induce seepage destabilization, and it is also a process that sudden water catastrophe must go through. In order to investigate the direct relationship between stress conditions, water pressure conditions, and gradation structure on the pore structure of rock samples, the steady-state percolation method was used to investigate the percolation test system of variable-mass crushed rock masses. The results show that: 1) the structural characteristics of rock grains under the same stress environment are closely related to their extrusion fragmentation process and the softening and scouring effect of water. Rubbing, rotating, fracturing, grinding and plugging are the main forms of action of their intergranular action. 2) The filling particles before and after the loss meet the fractal law and have fractal characteristics. 3) The percentage of fine particles in the whole process of infiltration loss is as high as 34.4%. The adjustment of pore structure is related to the particle size gradation, and the reciprocal action of water flow will form a stable water-conducting channel. 4) The sudden water process of the specimen under particle loss can be divided into three stages: initial seepage, catastrophic destabilization and pipe flow surge.


Electronics ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 177
Author(s):  
Mateusz Zychlewicz ◽  
Radoslaw Stanislawski ◽  
Marcin Kaminski

In this paper, an adaptive speed controller of the electrical drive is presented. The main part of the control structure is based on the Recurrent Wavelet Neural Network (RWNN). The mechanical part of the plant is considered as an elastic connection of two DC machines. Oscillation damping and robustness against parameter changes are achieved using network parameters updates (online). Moreover, the various combinations of the feedbacks from the state variables are considered. The initial weights of the neural network and the additional gains are tuned using a modified version of the Grey Wolf Optimizer. Convergence of the calculation is forced using a new definition. For theoretical analysis, numerical tests are presented. Then, the RWNN is implemented in a dSPACE card. Finally, the simulation results are verified experimentally.


Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 419
Author(s):  
Piotr Derugo ◽  
Krzysztof Szabat ◽  
Tomasz Pajchrowski ◽  
Krzysztof Zawirski

This paper presents original concepts of control systems for an electrical drive with an elastic mechanical coupling between the motor and the driven mechanism. The synthesis procedure of the speed controller uses a proposed quality index (cost function) of system operation ensures the minimization of both tracking errors and torsional vibrations. Proper selection of the cost function focusses more on the reduction of torsional vibrations due to their negative influence on the drive’s mechanical coupling vitality. The omission of the plant identification of an adaptive fuzzy controller was proposed. Two types of fuzzy controllers were analyzed, namely with type I and type II fuzzy membership functions. The novelty of the presented approach is in the application of a Petri transition layer in a type II fuzzy controller which reduces the numerical complexity in case of a large number of complicated type II fuzzy sets. The presented simulation and experimental results prove that the best dumping of mechanical vibrations ensures the adaptive fuzzy controller with type II functions and a Petri transition layer.


Author(s):  
Younki Cho ◽  
Ryan Lo ◽  
Keerthana Krishnan ◽  
Xiaolong Yin ◽  
Hossein Kazemi

Systems ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 5
Author(s):  
Bo Sung Kim ◽  
Joon Kyu Lee

Numerical modeling is important for exploring the fundamental processes occurring in rock and for evaluating the real performance of structures built on and in rock mass system, and thus for supporting the design of rock engineering problems. Estimating the stability of rock mass foundation systems entirely based on a theoretical approach is a complicated task if there exists overlapping of their potential collapse modes. This paper applies finite element limit analysis to evaluate the bearing capacity of equally spaced multiple strip footings resting on rock mass obeying the modified non-linear Hoek–Brown failure criterion. Numerical solutions are expressed in terms of the efficiency factor that is dependent on the spacing between footings, as well as the rock mass properties. In addition, the effects of surface surcharge and footing roughness are quantified. The maximum spacing at which the interfering effect of adjacent footings becomes disappeared is evaluated and an algebraic expression for approximating the maximum spacing is proposed. Failure mechanisms for a few cases of rock mass under multiple strip footings are examined.


Author(s):  
Togay KÜPELİ ◽  
Yakup Harun ÇAVUŞ ◽  
Büşra UZUN ◽  
Mustafa Özgür YAYLI

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8479
Author(s):  
Karol Wróbel ◽  
Kacper Śleszycki ◽  
Krzysztof Szabat ◽  
Seiichiro Katsura

This paper proposes a new estimation algorithm based on the Luenberger observer methodology and multilayer concept. The proposed multi-layer Luenberger observer (MLO) is implemented in the control structure designated for a two-mass system. Two types of aggregation mechanism are evaluated in the paper. The MLO ensures better estimation quality of the mechanical state variables: motor speed, shaft torque, load speed and load torque, as compared to the classical single observer. The more accurate estimated states, the more precise closed-loop control is guaranteed. MLO is designated for the system where initial conditions of the plant are not known or the state variables can change rapidly (load torque in the considered case). The estimation algorithm and control strategy is evaluated through simulation and experimental tests. The obtained results confirm efficiency of the proposed MLO.


2021 ◽  
Author(s):  
Pengcheng Wang ◽  
Zhimin Tao ◽  
Xinkai Wu ◽  
Xiaozheng He ◽  
Bin Zhou

Sign in / Sign up

Export Citation Format

Share Document