Robotic Systems and Applications
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Use of fragility curves to assess the seismic vulnerability of soft rock tunnels: a review
Get PDFDue to their distinct geotechnical and structural features, soft rock tunnels pose serious issues because of their seismic sensitivity. These tunnels, often constructed in formations with lower shear strength and higher deformability, are particularly susceptible to damage during earthquakes. Fragility curves, which graphically represent the probability that a structure may sustain damage up to or beyond a particular threshold as a function of seismic intensity, are essential tools for evaluating the seismic resilience of these infrastructures. This research looks closely at the use of fragility curves to assess the seismic vulnerability of soft rock tunnels. Exploring the fundamental concepts and methodologies involved in constructing fragility curves, including seismic hazard analysis, structural modeling, damage state definition, data collection and statistical analysis is looked at first. The review highlighted the integration of soft rock characteristics such as strength and deformation properties into the fragility assessment process. Key developments in the topic are covered such as how machine learning and Bayesian inference might improve the precision and usefulness of fragility curves. The paper identified key findings such as the high sensitivity of fragility curves to geotechnical properties and seismic intensity levels and emphasized the importance of accurate data collection and model calibration. Important gaps in seismic risk evaluations are filled by integrating cutting-edge methodologies, such as Bayesian inference and real-time machine learning models that clarify the seismic behaviour of soft rock tunnels in the real world. For the purpose of strengthening earthquake-resistant infrastructure in earthquake-prone areas, engineers, scholars and policymakers are given practical insights
A novel problem and algorithm for solving permuted cordial labeling of corona product between two graphs
Get PDFThis study has come up with a new application of permuted cordial labeling initiated by two graphs based on their corona product, furthering the cause of a better comprehension of and research into specific types of graphs. The Permuted cordial labeling construction for the corona product of graphs consisting of paths, cycles, second power of a path and second power of cycle graphs may facilitate the consideration of the properties and structures of the graphs. It helps us to study its topological properties, connectivity images, symmetries and other properties
LSGAN-Transformer life prediction method for rolling bearings under few samples
Get PDFAiming at the problem that it is difficult to obtain a large amount of data for bearings with complex working conditions, which leads to the inability to accurately predict their life, a rolling bearing life prediction method based on few samples, LSGAN-Transformer, is proposed. A dropout layer is added to the LSGAN generator to avoid the overfitting phenomenon that often occurs during few-sample training. The normalization of each layer in the traditional Transformer model is moved forward to the input of the decoder and encoder submodules before the residual network, forming a direct gradient path from input to output, avoiding the problem of excessive expected gradient near the output layer that often occurs in the traditional Transformer network. Verification on the PHM2012 dataset and the XJTY-SY dataset shows that the MAE and RMSE of the proposed method are greatly improved; compared with other common prediction models, the MAE and RMSE of the proposed method are improved by 30.61 % and 35.93 % respectively
Research on fault diagnosis of rolling bearings based on multi-method fusion
Get PDFTo address the limitation that Variational Mode Decomposition (VMD) relies on empirical settings for the mode decomposition number K and penalty factor α, this paper proposed the RIME-VMD-KNN method for bearing fault diagnosis. Specifically, the RIME algorithm was used to intelligently optimize K and α of VMD, breaking the reliance on experience; Pearson Correlation Coefficient (PCC) was adopted to screen Intrinsic Mode Functions (IMFs) with high fault correlation for signal reconstruction, preserving key features; and the sample entropy of the reconstructed signal was input into KNN for fault identification. Experiments show that the optimization performance of RIME is superior to that of GA, GWO and AOA; the generalization ability is verified by supplementary tests on the XJTU-SY dataset; KNN is simpler and more efficient than SVM, proving the rationality of its selection; the confusion matrix and multiple random cross-validation confirm stability; and computing time and resource data are provided to verify the feasibility of embedded deployment. This method improves the reliability and real-time performance of diagnosis and has engineering value
Fuzzy dynamic self-tuning based linear active disturbance rejection control for PMSM speed control
Get PDFIn this paper, a novel control approach, namely fuzzy dynamic self-tuning-based linear active disturbance rejection control (FDS-LADRC), is proposed for the speed loop system of permanent magnet synchronous motors (PMSMs). Specifically, a control framework based on the linear active disturbance rejection control (LADRC) is presented. Fuzzy dynamic self-regulators are developed to enable simultaneous adaptive adjustments of both the controller and observer parameters. Additionally, the stability analysis is provided. A series of numerical simulations demonstrates that FDS-LADRC achieves superior adaptivity, transient performance, disturbance rejection capability, and anti-noise ability under various operating conditions. For instance, during no-load startup, compared with the traditional LADRC, nonlinear active disturbance rejection control (ADRC), a variant of FDS-LADRC named IT2FDS which utilizes interval type-2 fuzzy systems as fuzzy dynamic self-regulators, a state-of-the-art fractional-order ADRC with fuzzy self-tuning (FSFOADRC), and sliding mode control (SMC), FDS-LADRC reduces overshoot by 10.82 %, 13.55 %, 7.36 %, 5.53 %, and 3.94 %, respectively, and shortens settling time by 0.0132 s, 0.0076 s, 0.0139 s, 0.0009 s, and 0.0156 s, respectively. Finally, corresponding real-world experiments are conducted to validate the effectiveness and superiority of FDS-LADRC
Analysis of dynamic response characteristics of vehicle-mounted tank based on the finite element method
Get PDFThe vehicle-mounted tanks face prominent challenges in balancing dynamic safety, including vibration resistance and fatigue durability under complex transportation conditions. A rigid-flexible coupled finite element model, consisting of the base, tank body, and frame, was established. Vibration response analysis was conducted in accordance with ride comfort standards and road excitation requirements. Rigid-flexible coupled simulations were implemented with consideration of vertical acceleration inputs and road unevenness. For random vibration, power spectral density analysis demonstrated that the tank structure was prone to resonance in specific frequency bands. For structural optimization, key dimensions were selected as design variables, including vertical thickness, longitudinal thickness, middle width, and lateral width. An optimization mathematical model was established, and the Sequential Quadratic Programming (SQP) algorithm was adopted to solve the constrained nonlinear multi-objective optimization model. Through optimization calculations, the structure achieved 4.93 % reduction in mass, 37.3 % decrease in stress, and 37.1 % increase in the first-order natural frequency, thereby effectively balancing the requirements of lightweight design, structural strength safety, and anti-resonance performance. This study provided a comprehensive methodology for the dynamic analysis and optimization of vehicle-mounted tank containers, offered key technical support for advancing innovative studies in transportation and vibration engineering
Aeroelastic stability analysis and optimal PID control strategy simulation for large-scale HAWT blades
Get PDFAiming at the classical flutter problem of wind turbine blades, a wind turbine blade aeroelastic model is constructed based on the typical leaf cross-section model of spring-mass-damper and the classical flutter aerodynamic model. The stability analysis of the wind turbine aeroelastic model is carried out using the Liapunov indirect method, and the effects of different parameters on stability are compared. Combining the aeroelastic model with the second-order model of pitch exciter, the pitch aeroelastic equation of the system is given, and the system controllability is analyzed. The optimal PID pitch control is designed, and the Simulink simulation is performed to explore the optimal combination under different combinations by selecting the torsion angle and waving displacement as the error signals, and different combinations of the torsion angle, waving displacement, and pitch angle as the optimal control objectives, respectively. The simulation results show that when the torsional angle is used as the error feedback signal and the torsional angle is set as the optimal control objective, it is the only scenario without overshoot. The overshoot in other cases ranges from 30 % to 500 %. In terms of adjustment time, this scenario also demonstrates good performance. Although it is not the fastest, the gap from the fastest is no more than 20 %. Therefore, using the torsional angle as the error feedback signal and the torsional angle as the optimal control objective is the best choice
Key construction technologies for in-situ reconstruction of a continuous girder bridge onto a steel truss arch bridge
Get PDFThis study explains the challenges of reconstructing a continuous beam bridge and its effects on the performance of adjacent structures. Combined in-situ demolition and modification of continuous beam bridges with the new construction of steel truss arch bridges, an integrated construction method is established. Taking a bridge as a construction platform, the temporary fixation technology is used for the tie beam hook. Various erection techniques of the bridge and tie beam construction support frame, as well as the construction techniques of Truss steel arch and wind bracing are studied and explored. In addition, the method of simultaneous disassembly and construction methods of crossbeams are also studied. Finally, a new technology is developed to reconstruct Truss arch bridge on continuous beam bridges
Analysis of a 10 kW mini pumped hydro storage plant with solar integration in Uzbekistan
Get PDFThis paper presents the design and performance evaluation of a 10 kW mini pumped hydro storage (PSH) system integrated with solar photovoltaic (PV) energy for rural electrification in Uzbekistan. The system stores excess solar energy during the day and generates 60 kWh electricity during evening hours at a rated power of 10 kW, with an overall efficiency of about 75 %. The optimized design includes a Cross-Flow turbine (200 mm diameter, 600 rpm), a 10 m head, and 58 solar panels of 400 W. The study demonstrates that such small PSH systems can provide a cost-effective, long-lifetime alternative to chemical batteries in rural power applications
