scholarly journals Multistage Asymmetric Rotors Coaxial Measurement Stacking Method Based on Minimization of Exciting Force

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1054
Author(s):  
Yongmeng Liu ◽  
Yingjie Mei ◽  
Chuanzhi Sun ◽  
Pinghuan Xiao ◽  
Ruirui Li ◽  
...  
Keyword(s):  
Vibration Amplitude ◽  
High Speed ◽  
Geometric Error ◽  
Exciting Force ◽  
Propagation Model ◽  
Assembly Method ◽  
Geometric Center ◽  
Asymmetric Rotor ◽  
Rotor Equipment ◽  
Geometric Error Measurement

The unbalanced exciting force of high-speed rotary asymmetric rotor equipment is the main factor causing rotor vibration. In order to effectively suppress the vibration of the asymmetric rotor equipment, the paper establishes a multistage asymmetric rotor coaxial measurement stacking method that minimizes the exciting force. By analyzing the propagation process of the centroid of the multistage asymmetric rotor assembly and analyzing the relationship between the geometric center and the centroid of a single asymmetric rotor, a multistage asymmetric unbalanced rotor propagation model based on geometric center stacking is established. The genetic algorithm is used to optimize the unbalance of the multistage asymmetric rotors. Combined with the vibration principle under the exciting force, the vibration amplitude of the left bearing at different rotation speeds under the minimization of the exciting force and the random assembly phase is analyzed. Finally, the experimental asymmetric rotors are dynamically measured, combined with the asymmetric rotors’ geometric error measurement experiment. The experimental results confirm that the vibration amplitude of the assembly phase with the minimum exciting force is smaller than the vibration amplitude under the random assembly phase at three-speed modes, and the optimization rate reached 73.2% at 9000 rpm, which proves the effectiveness of the assembly method in minimizing the exciting force.

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

Influencing factors of rotary table geometric error measurement using four-station laser tracers

2021 ◽  
Author(s):  
Jun Zha
Keyword(s):  
Coordinate System ◽  
Influencing Factors ◽  
Measurement Errors ◽  
Geometric Error ◽  
Measurement Process ◽  
Length Measurement ◽  
Numerical Control ◽  
Error Measurement ◽  
Rotary Table ◽  
Geometric Error Measurement

Abstract The laser tracer multi-station measurement method has outstanding performance in computerized numerical control (CNC) rotary table geometric error measurement and separation. However, external factors, such as layout, selected distance between the target mirror and measurement coordinate system, uncertainty of the length measurement, selection of measuring radii for the rotary table, and installation deviation from the target mirror center to the rotary table surface, have negative effects on the results. In this research, the position dilution of precision in the global positioning system measurement process is introduced to evaluate the influence of the laser tracers’ positions on measurement errors. The optimal measurement layout of the laser tracer is used to select the distance between the target mirror and XY plane of the laser tracer measurement coordinate system for the simulation. Then, the influence of the length measurement uncertainty on the laser tracer self-calibration and point measurement results used for calibration is examined based on the Monte Carlo simulation method. Different measurement radii in the rotary table are selected, and four-station laser tracers are used to perform the virtual measurement and evaluate the maximum uncertainty in the X, Y, and Z directions to further determine the best measurement radii of the CNC rotary table. Finally, the effects of the deviation of the target mirror installation center on the geometric error items of the CNC rotary table are quantitatively examined through a simulation. The analysis of the influencing factors in the geometric error measurement and separation process of the CNC rotary table can help further understand how the final results are formed, so as to control the influencing factors during the measurement process and finally optimize them in practice.

scholarly journals Geometric Error Identification and Analysis of Rotary Axes on Five-Axis Machine Tool Based on Precision Balls

2019 ◽  
Vol 10 (1) ◽  
pp. 100 ◽  
Author(s):  
Chuandong Li ◽  
Xianli Liu ◽  
Rongyi Li ◽  
Shi Wu ◽  
Houwang Song
Keyword(s):  
Machine Tool ◽  
Error Term ◽  
Geometric Error ◽  
Contact Method ◽  
Error Measurement ◽  
Spatial Error ◽  
Term Operation ◽  
Rotary Axes ◽  
Geometric Error Measurement ◽  
Five Axis

This paper presents the design of a precise “ball-column” device to efficiently and accurately measure the geometric error terms of both rotary axes of the five-axis machine tool. A geometric error measurement method of spherical contact was proposed based on the influence of the geometric error term from a five-axis machine tool rotating axis on the integrated geometric error of the machine tool. A multiple degree of freedom, step-by-step contact method based on on-machine measure for measuring the spherical center point is proposed, and the solution formula of each geometric error term of the rotating axis is established, respectively. This method can identify 12 geometric errors based on the influence of one rotating axis on another rotating axis after long term operation. The spatial error field of the five-axis machine tool was constructed by analyzing the error law of the two rotating axes of machine tools based on various positions and postures. Finally, after the comparison of the experiment, the results showed that the accuracy of the developed error measurement device reached 91.8% and the detection time was as short as 30–40 min.

Development of a Six-Degree-of-Freedom Geometric Error Measurement System for a Meso-Scale Machine Tool

2005 ◽  
Vol 127 (4) ◽  
pp. 857-865 ◽  
Author(s):  
Sang Won Lee ◽  
Rhett Mayor ◽  
Jun Ni
Keyword(s):  
Beam Splitter ◽  
Geometric Error ◽  
Laser Beams ◽  
Error Measurement ◽  
Error Components ◽  
Laser Module ◽  
Cube Beam Splitter ◽  
Six Degree Of Freedom ◽  
Geometric Error Measurement ◽  
Meso Scale

This paper presents the development of a six-degree-of-freedom (DOF) geometric error measurement (6GEM) system that can be applied to the simultaneous measurement of six geometric error components of the moving axes of a meso-scale machine tool (mMT). The system consists of a laser module constructed by a cube beam splitter and a pigtailed laser diode, three two-dimensional position sensitive detectors (PSDs), and an additional cube beam splitter. The laser module moving with the positioning system of the developed mMT testbed generates two perpendicular laser beams, one of which is further divided into two laser beams at the second cube beam splitter. These three laser beams are detected by the three PSDs, and the full pose of the laser module is then calculated simultaneously by forward and inverse kinematic computations. The calculated full pose of the laser module is translated into six-DOF geometric errors of the mMT testbed. A series of experiments are performed to demonstrate the effectiveness and accuracy of the proposed 6GEM system. The experimental results show that the measurement accuracy of the 6GEM system was better than ±0.6μm for translational error components and ±0.6arcsec for angular error components.

scholarly journals Control method of high-speed switched reluctance motor with an asymmetric rotor magnetic circuit

2016 ◽  
Vol 65 (4) ◽  
pp. 685-701 ◽  
Author(s):  
Piotr Bogusz ◽  
Mariusz Korkosz ◽  
Jan Prokop
Keyword(s):  
High Speed ◽  
Magnetic Circuit ◽  
Control Method ◽  
Torque Ripple ◽  
Negative Slope ◽  
Electromagnetic Torque ◽  
Switched Reluctance Motors ◽  
Switched Reluctance ◽  
Asymmetric Rotor ◽  
Current Flows

Abstract In the paper, the modified (compared to the classical asymmetric half-bridge) converter for a switched reluctance machine with an asymmetric rotor magnetic circuit was analysed. An analysis for two various structures of switched reluctance motors was conducted. The rotor shaping was used to obtain required start-up torque or/and to obtain less electromagnetic torque ripple. The discussed converter gives a possibility to turn a phase off much later while reduced time of a current flows in a negative slope of inductance. The results of the research in the form of waveforms of currents, voltages and electromagnetic torque were presented. Conclusions were formulated concerning the comparison of the characteristics of SRM supplied by the classic converter and by the one supplied by the analysed converter.

Experimental Study on Backlash Compensation of CNC Machine Tool

2012 ◽  
Vol 580 ◽  
pp. 419-422 ◽  
Author(s):  
Xiao Long Shen ◽  
Jia Ying Hu ◽  
Ming Jun Zhang ◽  
Lai Xi Zhang
Keyword(s):  
Machine Tool ◽  
Evaluation System ◽  
High Speed ◽  
Basic Feature ◽  
Geometric Error ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Position Accuracy ◽  
Different Types ◽  
Types Of Error

The backlash compensation has a great effect on the synthetical precision of CNC machine tool. Here, the measuring and backlash compensating technologies were investigated for high-speed CNC machine tool. Following, the backlash compensation of the synthetical geometric error of the interpolatimg movement and the evaluation system of position accuracy were proposed during CNC machine tool processing. The results indicate that the basic feature of error is established and provides a basis for putting forward the new error measurement method under the essential measuring condition. It also could be applied for different types of error compensation, shows that the backlash of the milling processing could be well compensated.

scholarly journals A Modified Sequential Multilateration Scheme and its Application in Geometric Error Measurement of Rotary Axis

Procedia CIRP ◽  
2015 ◽  
Vol 27 ◽  
pp. 313-317 ◽  
Author(s):  
Zhang Zhenjiu ◽  
Ren Mingjun ◽  
Liu Mingjun ◽  
Wu xinmin ◽  
Chen yuanbo
Keyword(s):  
Geometric Error ◽  
Error Measurement ◽  
Rotary Axis ◽  
Geometric Error Measurement
Sign in / Sign up

Export Citation Format

Share Document