A comparison between the results obtained by the MsP method and the numerical integration method proves that the former is ideal and credible in most regions. The effects of the time-varying parameters and the nonlinear deenthing caused by the gear teeth clearance on the amplitude–frequency characteristics of TsSCS components are studied. This is a part of research on transmission gears' thermal deformation for application in warship power rear drive systems.
In order to improve the efficiency of identifying parameters using the maximum likelihood method and to avoid the sensitivity of initial values, a proposed method that combines the advance and retreat method with the micro-genetic algorithm allows the initial value, the iterative increment, and the search interval to be gradually changed, and the initial value to start from zero, which ensures a stable and fast convergence compared with other algorithms.
This study proposed and verified a new idea for the crushing system of a mobile pellet harvester. As the key components of the crushing mechanism, the theoretical design calculation was given, and Ansys software was used to verify the feasibility of the design, specifically by computing the strength and stiffness. Field tests were conducted, and the test results met the requirements. This design can promote the further development of a mobile pellet harvester.
An electrohydraulic servo four-legged heavy-duty (FLHD) robot has been designed and developed. An integration layout cylinder design scheme for a non-lightweight hydraulic servo four-legged robot with high loads and torque of the hip joint is proposed, and the mathematical element analysis model for a parallel-executed cylinder (PEC) system is derived. A design idea of a force–position hybrid control scheme is determined for the PEC.
A novel structure of controlled multi-flow channel magnetorheological fluid semi-active mount is proposed, including four controlled channels and one rate-dip flow channel. For the proposed structural model, magnetic circuit analysis, rate-dip flow channel optimization design, and magnetorheological fluid mount damping analysis are performed, by developing a mathematical model for the semi-active mount of controlled multi-channel magnetorheological fluid.
This paper presents a concurrent tolerance design methodology for predicting the tolerance. This method integrates the product design with manufacturing and inspection to realize the balance of design tolerance, process tolerance, and cost. The proposed method was finally tested on the gap design between the taillight and bodyside of an automobile. The result shows the proposed approach improves design efficiency, shortens the development cycle, and reduces development costs.
Springback is an inevitable problem in the local bending process of hull plates, which leads to low processing efficiency and affects the assembly accuracy. Therefore, the prediction of the springback effect, as a result of the local bending of hull plates, bears great significance. In total, four springback prediction models, based on genetic and back propagation neural
network (GA-BPNN) algorithms and the improved particle swarm optimization (PSO)-BPNN algorithms, are established.
It is difficult to achieve high-precision control due to friction of nonlinearity by traditional linear control methodology for the classical drive feed system at low speed. Here, the double-drive differential feed system is proposed to reduce the influence of the nonlinear friction at the ball screw pair of a linear feed system operating at low speed.
With establishing the mathematical model of the height of additive remanufacturing repair (ARM-repair), the precise position with theoretical basis of the weld seam under different wire-feeding speeds is obtained. The cooling effect is analyzed by numerical analysis and verified by experiments. The study can provide scientific theoretical support for blade ARM-repair height and related cooling parameters and has positive significance for improving blade repair technology.
The paper studies the three-dimensional contact finite element model of a double helical gear-shaft-bearing system based on the load-bearing contact analysis of the tooth surface. The results show that the tooth surface bearing contact of the system has the phenomenon of partial load due to the supporting deformation, and the unmodified herringbone gear has obvious contact stress concentration, which can be effectively improved by gear tooth modification.
In this paper, a new parameter, the compliance ratio λ, which could reflect the sensitivity of the main form of the flexible hinge's output displacement, is proposed and discussed in detail. The optimization of the compliant actuator is carried out analyzing the compliance features of different types of flexible hinges. Finally, an actual precision linear position platform will be taken as an example, to prove the key performance of the compliant actuator is much better.
Few pieces of literature could be found on vibration investigations of the 3K planetary gear set, a basic planetary drive structure with a more compact structure and wider transmission ratio range than the 2K-H. In this paper, the features of casing vibration and output torsional vibration are analyzed by establishing a dynamics model of a 3K-II gearbox. The advantages and disadvantages of these two vibration signals as a basis for 3K planetary gear system fault diagnosis are also compared.
The approximate calculation of a Stockbridge type damper's natural frequencies and its sensitivity were studied. The low-order frequency is highly sensitive to the cable's length, moderately sensitive to the damper's mass, and slightly sensitive to the eccentric distance and the damper's gyration radius. The high-order frequency is highly sensitive to the cable's length and the damper's gyration radius, moderately sensitive to the damper's mass, and slightly sensitive to the eccentric distance.
This paper aims to investigate the problem of the complex structure optimization of a thin-film diffraction imaging system. A method based on the Kriging model and the improved particle swarm algorithm is proposed to optimize the structure of the thin-film diffraction imaging system. After optimization, the flexible vibration of the improved thin-film diffraction imaging system is effectively suppressed, and the stiffness and stability of the supporting structure are significantly improved.
The monk I-Hsing (621–727) was an outstanding astronomer and mathematician during the Tang Dynasty. He was the first person to use scientific methods to measure the length of the meridian. History records that the waterwheel drove his hydromechanical clock, and the time-reporting device could accurately tell the time. Therefore, his hydromechanical clock had a timing function and an escapement regulation device.
This paper proposes a global interpolation algorithm that uses the trajectory pattern method for synthesizing low-harmonic trajectories. The synthesized trajectories and axis kinematic profiles are all smooth and only contain the fundamental frequency and its first three harmonics, which could avoid excitation of the system modes of vibration and reduce demand on the actuator dynamic response, thereby allowing the system to operate at higher speed and precision.
The variable hyperbolic circular-arc-tooth-trace (VH-CATT) cylindrical gear is a new type of gear. In order to research the contact characteristics of the VH-CATT cylindrical gear, tooth surface mathematical models of this kind of gear pair are derived based on the forming principle of the rotating double-edged cutting method with great cutter head in this regard.
The problem of inverse folding, determining the distribution of creases according to the desired shape, requires luck and artist inspiration, and it is a very complicated process. Here, we try to solve an inverse folding problem about a folding toy and get some kirigami patterns. It opens up a new way to solve the problem and can also help students understand the theory of mechanisms and machines.
A universal test-machine-based mechanically driven friction device was designed and manufactured. Friction tests were conducted on a third-generation high-strength steel QP980 with flat and curved dies at different pulling speeds and clamping forces. The formula for calculating the friction coefficients between curved contact surfaces was derived.