Aiming at improving the accuracy of planetary gearbox fault diagnosis, an integrated scheme based on dimensionality reduction method and deep belief networks (DBNs) is presented in this paper. Firstly, acquired vibration signals are decomposed into mono-component called intrinsic mode functions (IMFs) through ensemble empirical decomposition (EEMD), then Teager–Kaiser energy operator (TKEO) used to track instantaneous amplitude (IA) frequency (IF) a modulation (AM) (FM) signal. Secondly,...

The permanent magnet synchronous motor is extensively used in robots due to its superior performances. However, mostly operate unstructured and dynamically changing environments. Therefore, it urgent challenging achieve high-performance control with high security reliability. This paper investigates an accelerated adaptive fuzzy neural prescribed performance controller for the PMSM solve chaotic oscillations, output constraint, full-state constraints, input uncertain time delays, unknown...

Abstract At present, the mean value of meshing stiffness and gear backlash is a fixed in nonlinear dynamic model. In this study, wear considered model time-varying stiffness. With increase operating time, decreases increases. A six degrees-of-freedom new rigid-flexible pair established with backlash. The behaviors transmission system are studied through bifurcation diagrams time as control parameters. Then, characteristics analyzed using excitation frequency parameters at four points....

In this study, a new rigid–flexible gear with metal rubber is proposed to reduce the vibration of transmission system. A nonlinear dynamic model nine degrees freedom considering bearing clearance, backlash, surface friction, and time-varying meshing stiffness established. The nondimensional system obtained bifurcation characteristics pair rigid are analyzed when damping coefficient is, respectively, 0.03 0.1. result shows that motion state more stable. responses compared as well through...

For mechanical moving components in space applications, the accelerated life test for verification of reliability is very important. Since traditional methods liquid lubrication have some limitations, a new method proposed this paper, which harmonic driver used as object study. First, performed vacuum. The results show that adhesive wear caused by asperity contact at wave generator–flexspline interfaces crucial factor governing driver. To clarify lubricant film behavior interface, mixed...

Abstract In this study, a nonlinear dynamic model of spur gear transmission system with non-uniform wear is proposed to analyze the interaction between surface and characteristics. A quasi-static presented, consideration effects operating time on mesh stiffness backlash. Furthermore, six degrees-of-freedom established considering friction, time-varying backlash, stiffness, eccentricity, Runge–Kutta method applied solve model. The bifurcation chaos in change excitation frequency are...

A tooth profile is of significant importance to the performance a harmonic drive. Available studies about designing only consider influence on meshing characteristics from macro perspective. However, effects surface roughness and contact geometry lubrication micro perspective are rarely reported. In present study, double-circular-arc used as basic flexspline. Based modified kinematic method, conjugate calculated circular spline obtained. On this basis, mathematical model for mixed drive with...

Transmission compliance and hysteresis behaviors are associated with harmonic drives. The experimental observation of a drive showed that these significantly degraded increasing service time, their accurate modeling is expected to improve the performance control system drive-based devices such as robot manipulators. In this paper, new model proposed capture transmission degradation. phenomenon represented through combination nonlinear stiffness component micro-sliding friction in tooth...

By considering the effects of multiple grooves, rubber deformation, and actual boundary conditions, steady elastohydrodynamic lubrication mathematical model dynamic Reynolds equation water-lubricated bearings are presented. The is solved numerically by finite difference method, stiffness damping coefficients calculated from real imaginary parts integrated pressure. Analysis results suggest that angular velocity, eccentricity ratio, groove configuration, radial clearance have significant on...

Purpose This paper aims to explore the possibility of converting nitrile butadiene rubber (NBR) water-lubricated bearing material into a self-lubricating by action polytetrafluoroethylene (PTFE) particles and water lubrication. Design/methodology/approach A group experimental studies was carried out on ring-on-block friction test. The physical properties, tribological properties interface structure PTFE-NBR composites filled with different percentages PTFE were investigated. Findings results...

Urban road detection with on-board monocular camera in vehicle is still a difficult problem due to its complexity. Combining the superpixel scene segmentation classification of texture and structure information scenes, this paper explores method from single image. Processing on large scale structural around small scale, obtaining accurate about edge segmentation, proved be robust by experiments. Experimental data show that our approach achieved relatively good results variety complex urban...

This paper presents a group of elastic Hydrodynamic lubrication (EHL) analyses to evaluate the effects micro-bottom shape on performance misaligned herringbone grooved axial piston bearing. Due time-consuming tasks introduced in grooves, complex bottom shape, rotation combined movement, and misalignments require high-speed computation. So new parallel numerical algorithm is proposed, which exhibits higher computing speed than normal successive over relaxation (SOR) method. The results...

Abstract Achieving faster convergence, smaller transient overshoots, and higher steady‐state tracking accuracy is essential to improve the efficiency, robustness, applicability of robotic manipulators. This article introduces an innovative adaptive fixed‐time uniform prescribed performance controller for manipulator facing model uncertainties unknown disturbances. Initially, by designing a modified function inspired variable superposition, this study redefines unified control problem into...