The decomposition effect of variational mode (VMD) mainly depends on the choice number K and penalty factor α. For selection two parameters, empirical method single objective optimization are usually used, but aforementioned methods often have limitations cannot achieve optimal effects. Therefore, a multi-objective multi-island genetic algorithm (MIGA) is proposed to optimize parameters VMD apply it feature extraction bearing fault. First, envelope entropy (Ee) can reflect sparsity signal,...

Aiming at the problem that it is difficult to extract fault features from nonlinear and non-stationary vibration signals of wind turbine rolling bearings, which leads low diagnosis recognition rate, a feature extraction method based on multi-island genetic algorithm (MIGA) improved variational mode decomposition (VMD) multi-features proposed. The effect VMD limited by number decompositions selection penalty factors. This paper uses MIGA optimize parameters. used decompose signal into...

The performance of the rolling bearing a spindle device is directly related to safety and reliability operation mine hoist. To extract vibration signal features effectively for fault diagnosis, feature extraction method based on parameter optimization variational mode decomposition (VMD) permutation entropy (PE) proposed. In addition, support vector machine (SVM) classifier used identify types. An analogue test effect noise sampling frequency VMD performance. Focused problem needing...

By analyzing nonlinear and nonstationary vibration signals from the spindle device of mine hoist, it is a challenge to overcome difficulty fault feature extraction accurately identify rotor-bearing system. In response this problem, paper proposes new approach based on variational mode decomposition (VMD), SVM, statistical characteristics such as variance contribution rate (VCR), energy entropy (EE), permutation (PE). Comparisons have gone evaluate performance rolling bearing defect by using...

In order to efficiently solve a forward kinematics of parallel manipulators for real-time applications, Jacobian free monotonic descent algorithm is proposed in this article. The system nonlinear equations specified 6-degree-of-freedom manipulator established using geometric analysis method. modified traditional Newton–Raphson method by employing first-order Taylor series expansion numerically approximate matrix. A factor employed preventing the iteration from divergence even with poor...

An electro-mechanical actuator (EMA) consists of an electric motor and a mechanical transmission (reducer). As the applications EMA in actuators flight control are increased, demand for accurate reliable fault diagnostic method its becomes important issue. In view traditional vibration-based diagnostics need extra hardware devices, this paper proposes extraction EMA, composed spiral bevel gears, harmonic-drive Brushless DC (BLDC), by monitoring stator current. The BLDC, drives with speed...

Shaoguan was hit by a extremely heavy rainstorm, and the mountain water catchment of Dabaoshan Tunnel in southern section Beijing Hong Kong Macao Expressway Guangdong increased sharply. Due to rapid rise groundwater level, mud gushed at ZK141+227 Dabaoshan, serious seepage occurred other areas, bringing soil into tunnel, which seriously hindered safe passage tunnel. According on-site investigation gushing, it found that there were branches sandwiched gushing out, same time, leakage foot some...

As a major auxiliary transportation equipment in coal mines, manually operated mining electric locomotives often cause accidents due to the complex and harsh environment. Reinforcement learning (RL) focuses on how agents take action environment maximize returns, which is helpful for achieving automatic control of locomotives. In this paper, RL applied autonomous locomotives, considering unsafe conditions such as avoidance dynamic obstacles maintaining safe distance from vehicle front. To...

The integrated friction characteristics will cause assembly states of electromechanical actuator abnormal in the factory stage. To solve this problem, paper presents a new method for identifying based on electrical motor current signal analysis. advantage is that it can be used to evaluate final performance stage actuator. A mathematical model established by MATLAB/Simulink, and are identified analysis method. Finally, identify state according experience affected practical application...

According to present situation of buildings energy conservation home and abroad, the analysis influencing factors on public building consumption, combined with year-round climate Jilin Province, according relevant state codes, standards, suitable efficiency evaluation system has been established. Taking sunshine department store architecture for example provide practical checking establishment then build set up a theoretical basis technical support.