Kinds Of Mechanical Devices Research Articles

Experimental study on cavitation inhibition in a butterfly valve with different plate shapes

A valve is a kind of mechanical device used to control the flow of fluid in pipelines or systems, which has a wide range of uses in various industrial, commercial, and household applications. When the fluid passes through the valve, cavitation often occurs in the valve, resulting in the valve not working properly and even damaging the valve and related systems. In this paper, experimental visualization was used to investigate cavitation evolution through a butterfly valve with different plate shapes under different pressure conditions. The results show that with the increase in the curvature of both sides of the butterfly plate and the increase in the total pressure condition, the cavitation type inside the butterfly valve will change from non-attached cavitation to attached cavitation. In addition, the maximum length and thickness of the attached cavitation bubbles gradually increase as well. However, when the shape of both ends of the butterfly plate is triangular, the adhesion ability to cavitation bubbles is greatly reduced. As the curvature increases, the frequency of the shedding of cavitation bubble gradually decreases, the volume of cavitation bubble increases, and the shedding of the cavitation bubble caused by the shock wave is more obvious. When the shape of both sides of the butterfly plate is triangular, the position where the bubble collapses is closer to the front end of the butterfly plate, and the shock wave generated by the bubble collapse will lead to the collapse of the attached cavitation bubble.

Control of Robot Arm Motion Using Trapezoid Fuzzy Two-Degree-of-Freedom PID Algorithm

Symmetries play very important in the dynamics of robot systems. The relevant control of robot arm motion with fault diagnosis including the optimized fuzzy algorithm based on the error rate adjustment P, I, D value (Fuzzy PID algorithm) model relies on symmetry principles. A robot is a kind of mechanical device that can program and perform certain operations and mobile tasks under automatic control. The manipulator is a very complex multi-input multi-output non-linear system and the main actuator of the robot. This paper focuses on the design of a control algorithm for a two-degree-of-freedom (2-DOF) manipulator. First, the mathematical model of a 2-DOF articulated manipulator is established, that is, the functional relationship between the input driving force vector and the output rotation angle vector of a 2-DOF manipulator. Then, a set of trajectory planning algorithms are designed by using gradient model control, which can calculate the trajectory of the end-effector of a 2-DOF manipulator according to the user’s task requirements. The experimental results verify the effectiveness of the proposed algorithm.

On the optimum absorber parameters: revising the classical results

The dynamic vibration absorber is a kind of mechanical device with inertia, stiffness, and damping. Once connected to a given structure or machine, it is capable of absorbing vibratory energy. As a result, the primary system can be protected from excessively high vibration levels. In this paper, we deal with classical Den Hartog’s model to clarify the known results and improve the mathematical component of this approach. We suggest the optimal choice of absorber parameters, which is slightly different and more general analytical approach. The comparison of two methods of optimization is carried out, and the corresponding error of calculus is estimated.

Temperature Field Simulation of Ballscrew Whirlwind Milling

Ball screw is the key parts of NC machine, precise instrument and many kinds of mechanical devices. Whirlwind milling is a new and effective thread manufacture technology. This article studies the internal heat conduction equation of whirlwind milling ball screw based on Heat Transfer, calculates ANSYS simulation result. The simulation results show that the surface temperature distribution rule and internal temperature distribution rule of a ballscrew is consistent. The article analyzes the influence factors of the thermal elongation. It provides a basis for compensating the thermal deformation error of whirlwind milling ballscrew.