Development of modularized in-pipe inspection robotic system: MRINSPECT VII+

This paper presents a modularized autonomous pipeline inspection robot called MRINSPECT VII+, which we recently developed. MRINSPECT VII+ is aimed at inspect in-service urban gas pipelines with a diameter of 200 mm. The robot consists of five basic modules: driving, sensing, joint, and battery modules. For nondestructive testing (NDT), an NDT module can be added to the system. The driving module uses a multiaxial differential gear mechanism to provide traction forces to the robot. The sensor module recognizes the pipeline element using position-sensitive detector (PSD) sensors and a CCD camera. The control module contains a computing unit and manages the robot’s autonomous navigation. The battery module supplies power to the system. Each module is connected via backdrivable active joint modules, which provide flexibility while moving inside narrow pipelines. Additionally, the wireless communication module helps the system communicate with the ground station. We tested MRINSPECT VII+ in real pipeline environments and validated its feasibility successfully.

Differential Gear Box To Reduce Vibration Using Different Materials For Vehicles-A Review

Whatever framework is embraced to coordinate the automobile to its thought process unit — be it a hand shift gearbox, a 'hot' shift gearbox or completely automatic unit, a complex and generally expensive mechanism is ordinarily included. More than expected plan office consideration is centeredaround this region of a recently imagined vehicle. Grounded plan systems for transmission gearing were accessible before the principal automobile or even the inner combustion motor was created; solid answers have in this way been generally accessible from the planning phase. The intricacy of the mechanisms has additionally requested, on account of amount delivered vehicles, thorough drawing designs of the variety of segments included with the goal that resilience stacking can be read and the requirement for exceptionally talented fitting, during get together, decreased. The present-day meaning of the creator's commitment is additionally improved by the need to guarantee without a doubt the base of expensive turn of events or creation changes. The cautious determination of gear ratios for a manual unit, or of control boundaries in an automatic one, can drastically influence the presentation or driveability of the completed vehicle.

Meshing Stiffness Parametric Vibration of Coaxial Contrarotating Encased Differential Gear Train

Planetary gears are widely used in mechanical transmission systems, but the vibration and noise affect their reliability and life. In this paper, the torsional dynamic model of an encased differential planetary gear with coaxial contrarotating outputs considering the time-varying meshing stiffness, damping, and phase difference of all gear pairs is established. By solving the equations of the derived system, three types of natural frequencies with different multiplicities of the system are obtained. The multiscale method is used to study the parametric vibration stability caused by the time-varying meshing stiffness, and the results are verified by numerical simulation. The dynamic characteristics of elastic meshing force are analyzed from time domain and frequency domain. The variation of the dynamic load factor of each gear pair with input speed and the relationship between its peak position and the natural frequency of the derived system are discussed. The results show that there is an unequal coupling phenomenon of meshing frequency between the meshing forces of different planetary sets. In the absence of external excitation, the meshing stiffness parameters not only excite the main resonance response of the system but also cause superharmonic resonance, subharmonic resonance, and combined resonance.

Dynamic Characteristics of Encased Differential Gear Train with Journal Bearing

Taking the marine encased differential gear train as an example, the relationship between the journal bearing parameters and the meshing force of the transmission system is analyzed. In this paper, the dynamic model of the encased differential gear train with journal bearing is established considering the factors of time-varying meshing stiffness and comprehensive transmission error. In this dynamic model, four stiffnesses and four damping coefficients are applied to characterize the asymmetry and interaction of the oil film stiffness and damping of planet bearing. The system responses are calculated by the Fourier series numerical algorithm. The results show that the introduction of journal bearing in encased differential gear train can contribute to gearbox vibration reduction. Moreover, the planet bearing parameters (e.g., clearance-to-radius ratio and eccentricity ratio) of the differential stage affect the meshing forces of both the differential and encased stages. In addition, the influence of the planet bearing parameters of the encased stage on the meshing force of the encased stage is more obvious than that of the differential stage. This work may develop a theoretical analysis framework for the design and manufacture of marine transmission systems in the future.

Simulation model of oscillations of the “sun gear – satellites” pair of turboprop engine planetary reduction gearbox in the presence of defects of tooth flanks

Defects of planetary reduction gearboxes of turboprop engines often cause excitation of high-frequency oscillations that bring about failures of compressor structural elements. The vibration behavior of these reduction grarboxes is a broadband process with the presence of a large quantity of vibration components, which significantly complicates the search for informative diagnostic indicators of defects. In order to simplify the procedure of identifying the vibrations caused by defects of toothed gearing a simulation model of the vibration behavior of a turboprop engine differential gear unit is proposed. The model takes into account kinematics and design of the gearbox, determines the structure of its vibration behavior in the presence of defects on the tooth flanks. Using the example of a commonly occurring defect in the form of wear of the teeth of the “solar gear – satellites” pair the adequacy of the model to the actual vibration behavior of the mechanism is shown.

Tribology Analysis of Spherical-Surface Contact Sliding Pairs Under Fluctuating Loads

Background: Spherical contacting surfaces are often designed to increase the contact surface area and bearing ability, and frequently suffer fluctuating loading, which will play an important role in tribological properties. Objective: Effects of high-frequency fluctuating loading on friction and wear performance of spherical- surface contact sliding pairs should be experimentally investigated. Methods: Bench tests with the differential gear contacting pairs of heave trucks were conducted under fluctuating loading generated by the traction force of spring-connecting hanging weights. Results: High amplitude of fluctuating loads tends to result in different wear forms such as fatigue wear, plowing damages, material side flow and plastic deformation. The amplitude of the fluctuating loads has significant influence on the tribological performance of the spherical-surface contact sliding pairs and is apt to break the frictional stability of the friction pairs indicated by the variation of the signal components of friction force signals decomposed by discrete wavelet transform method. Conclusion: The high frequency and large amplitude are the main factors of fluctuating loading that plays very important role in the tribological characteristics of spherical-surface contact sliding pairs.