scholarly journals An Analysis of Manufacturing Precision of Involute Worms Using a Kinematical Model

2021 ◽  
Vol 14 (1) ◽  
pp. 44-50
Author(s):  
Csongor Kelemen ◽  
Márton Máté
Keyword(s):  
Profile Error ◽  
Feed Direction ◽  
Tool Edge ◽  
Manufacturing Errors ◽  
Kinematical Model ◽  
Edge Profile ◽  
Input Element ◽  
The One ◽  
Theoretical Results ◽  
Worm Drive

Abstract The manufacturing precision of involute worms constitutes a major requirement. On the one hand, the worm constitutes the input element of the worm drive; secondly, the involute helical surface is the basic surface of an involute worm-hob. This paper presents an analytic comparison between the involute surfaces obtained using theoretical equations, kinematic simulation of the cutting and the surface charged with errors. The surface error is considered the distance along the normal direction to the theoretical surface, measured between this and the surface charged with simulated manufacturing errors. The main sources of errors are considered the center-error of the edge plane, the edge profile error and deviation of the axial feed direction from the axis of the worm. The theoretical results allow us to conclude that the influence of the edge profile error is the largest. It is followed by the parallelism error between the feed direction and the axis of the worm, and finally, the center error of the tool edge.

Dynamic Analysis and Experimental Research of Laser Cutting Machines

2014 ◽  
Vol 915-916 ◽  
pp. 31-34
Author(s):  
Qing Ping Zhang ◽  
Zheng Ru Wang ◽  
Yan Fang Wang
Keyword(s):  
Machine Tool ◽  
Modal Analysis ◽  
Laser Cutting ◽  
Machining Accuracy ◽  
Dynamics Analysis ◽  
Theoretical Base ◽  
Test Results ◽  
Cutting Machine ◽  
Manufacturing Errors ◽  
Theoretical Results

Vibration is one of the most important problems in laser cutting machine tool, which causes the manufacturing errors, also influences the machining accuracy of the parts. Modal analysis can calculate vibration type of structures. The paper presents how to use the powerful FEA software ANSYS to do the modal analysis on laser cutting machine tool and also studies the undamped free vibration on laser cutting machine tool. Finally, the test results and theoretical results were compared to verify the rationality of the modal, these provide theoretical base and conditions for dynamics analysis and optimal design.

Performance limitation of networked systems with controller and communication filter co-design

2016 ◽  
Vol 40 (4) ◽  
pp. 1167-1176 ◽  
Author(s):  
Jie Wu ◽  
Xi-Sheng Zhan ◽  
Xian-He Zhang ◽  
Tao Han ◽  
Hong-Liang Gao
Keyword(s):  
Networked Systems ◽  
Channel Noise ◽  
Frequency Domain Method ◽  
Minimum Phase ◽  
Error Signal ◽  
Optimal Network ◽  
Performance Limitation ◽  
The One ◽  
Theoretical Results ◽  
Two Parameter

This paper addresses the performance limitation problem of networked systems by co-designing the controller and communication filter. The tracking performance index is measured by the energy of the error signal. Explicit expressions of the performance limitation are obtained by applying the controller and communication filter co-design, and the optimal network filter is obtained by applying the frequency domain method. It is shown that the performance limitation is closely related to the unstable poles and the non-minimum phase zeros of a given plant under the one-parameter compensator structure, whereas, under the two-parameter compensator structure, the performance limitation is unrelated to the unstable poles of a given plant. It is also demonstrated that the performance limitation can be improved and the effect of the channel noise can be eliminated by using the controller and communication filter co-design. Finally, some typical examples are presented to illustrate the theoretical results.

scholarly journals A Comparison of the Probes with a Cantilever Beam and a Double-Sided Beam in the Tool Edge Profiler for On-Machine Measurement of a Precision Cutting Tool

Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 271
Author(s):  
Bo Wen ◽  
Sho Sekine ◽  
Shinichi Osawa ◽  
Yuki Shimizu ◽  
Hiraku Matsukuma ◽  
...  
Keyword(s):  
Cantilever Beam ◽  
Cutting Tool ◽  
Displacement Sensor ◽  
Laser Displacement Sensor ◽  
Tool Edge ◽  
Edge Profile ◽  
Measurement Principle ◽  
Beam Type ◽  
Tool Position ◽  
Tool Cutting

This paper describes a comparison of the mechanical structures (a double-sided beam and a cantilever beam) of a probe in a tool edge profiler for the measurement of a micro-cutting tool. The tool edge profiler consists of a positioning unit having a pair of one-axis DC servo motor stages and a probe unit having a laser displacement sensor and a probe composed of a stylus and a mechanical beam; on-machine measurement of a tool cutting edge can be conducted with a low contact force through measuring the deformation of the probe by the laser displacement sensor while monitoring the tool position. Meanwhile, the mechanical structure of the probe could affect the performance of measurement of the edge profile of a precision cutting tool. In this paper, the measurement principle of the tool edge profile is firstly introduced; after that, slopes and a top-flat of a cutting tool sample are measured by using a cantilever-type probe and a double-sided beam-type probe, respectively. The measurement performances of the two probes are compared through experiments and theoretical measurement uncertainty analysis.

scholarly journals Competitive Analysis for Online Leasing Problem with Compound Interest Rate

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Xingyu Yang ◽  
Weiguo Zhang ◽  
Weijun Xu ◽  
Yong Zhang
Keyword(s):  
Interest Rate ◽  
Competitive Analysis ◽  
The Other ◽  
Continuous Version ◽  
Numerical Examples ◽  
The Interest Rate ◽  
The One ◽  
Compound Interest ◽  
Theoretical Results ◽  
Deterministic Strategy

We introduce the compound interest rate into the continuous version of the online leasing problem and discuss the generalized model by competitive analysis. On the one hand, the optimal deterministic strategy and its competitive ratio are obtained; on the other hand, a nearly optimal randomized strategy is constructed and a lower bound for the randomized competitive ratios is proved by Yao's principle. With the help of numerical examples, the theoretical results show that the interest rate puts off the purchase date and diminishes the uncertainty involved in the decision making.

scholarly journals The fine-structure of some lines in the visible region of the spectrum of thallium III

1930 ◽  
Vol 129 (809) ◽  
pp. 43-47 ◽  
Keyword(s):  
Fine Structure ◽  
Visible Region ◽  
Nuclear Moment ◽  
Nichrome Wire ◽  
Spark Gap ◽  
High Tension ◽  
In Series ◽  
The One ◽  
Theoretical Results ◽  
Line Classification

From a study of the fine-structure of some lines in the arc spectrum of thallium Schüler and Brück concluded that the nucleus of the thallium atom possessed a moment of momentum given by ½ h /2π and this value was confirmed by work on the first spark spectrum of the element. The value of the nuclear moment being known the structure of the lines in the second spark spectrum could be predicted and the present paper is the account of an investigation of a number of these lines which lie in the visible region, a comparison being drawn between the experimental and the theoretical results. The source of light used was similar to the one employed by McLennan, McLay and Crawford in the excitation of the first and second spark spectra of thallium for the purpose of line classification. It consisted of a quartz tube about 50 cm. long and 1½ cm. in diameter with a plain window in each end and provided with aluminium electrodes sealed into side tubes. The metal whose spectrum was to be studied was scattered along thé bottom of the tube and the tube evacuated. The metal was then vaporised by hear supplied by a coil of nichrome wire wound on the tube. This coil must be wound non-inductively or the desired excitation will not be obtained. The high tension across the terminals was produced by joining them in series with the secondary of a 30,000-volt transformer and a spark gap of about 1 c. m., a condenser being connected in parallel.

scholarly journals On the spectrum of discrete-ordinates neutron transport problems

2021 ◽  
Vol 9 (2) ◽  
Author(s):  
Jesús Pérez Curbelo
Keyword(s):  
Discrete Spectrum ◽  
Neutron Transport ◽  
Anisotropic Scattering ◽  
Discrete Ordinates ◽  
High Anisotropy ◽  
Linear Transport Equation ◽  
The One ◽  
Transport Problems ◽  
Theoretical Results ◽  
Analytic Problem

Over the last six decades, the discrete spectrum of the neutron transport operator has been widely studied. Important theoretical results can be found in the literature regarding the one-speed linear transport equation with anisotropic scattering. In this work, the discrete-ordinates (SN) transport problem with anisotropic scattering has been considered and the discrete spectrum results in multiplying media have been corroborated. The numerical results obtained for the dominant SN eigenvalues agreed with the ones for the analytic problem reported in the literature up to a triplet scattering order. A compact methodology to perform the spectral analysis to multigroup SN problems with high anisotropy order in the scattering and fission reactions is also presented in this paper.

Complete, Minimal and Continuous Kinematic Error Models of Perfect Multi-DOF Joints for Parallel Manipulators

2020 ◽  
Author(s):  
Lingyu Kong ◽  
Genliang Chen ◽  
Zhuang Zhang ◽  
Anhuan Xie ◽  
Hao Wang ◽  
...  
Keyword(s):  
Parallel Manipulators ◽  
Error Model ◽  
Parallel Robots ◽  
Kinematic Error ◽  
Kinematic Calibration ◽  
Calibration Result ◽  
Calibration Methods ◽  
Manufacturing Errors ◽  
The One ◽  
Serial Chains

Abstract Kinematic error model plays an important role in improving the positioning accuracy of robot manipulators by kinematic calibration. In order to get a better calibration result, the error model should satisfy complete, minimal and continuous criteria. In order to meet the complete requirement, the multi degree-of-freedom (DOF) joints, such as universal or spherical joint in parallel robots, have to be regarded as serial chains formed by multiple independent single DOF joints, such that the manufacturing errors of these joints can be considered. However, several previous work found that these manufacturing errors for some parallel manipulators have little effect on the accuracy improvement. Besides, considering these kind of errors will cause the kinematics to be much more complicated. Therefore, under the assumptions of perfectly manufactured universal, spherical and cylinder joints, a complete, minimal and continuous (CMC) error model is presented in this paper. The identifiability of the kinematic errors of these multi-DOF joints are analytically analyzed. In order to verify the correctness and effectiveness of the proposed method, a numerical simulation of kinematic calibration is conducted on a 6-UPS parallel manipulator. The calibration result is also compared to the one derived from the error model with 138 error parameters. Since the error model and calibration methods are described uniformly, it can be applied to most parallel manipulators.

scholarly journals Theoretical considerations concerning the profile error of the thread flank

2018 ◽  
Vol 178 ◽  
pp. 01006
Author(s):  
Laurenţiu Slătineanu ◽  
Oana Dodun ◽  
Irina Beşliu Băncescu ◽  
Ionel Coman ◽  
Adrian Ghionea ◽  
...  
Keyword(s):  
Analytical Method ◽  
Cylindrical Surface ◽  
Cutting Tool ◽  
Simplified Model ◽  
External Diameter ◽  
Profile Error ◽  
Tool Edge ◽  
Theoretical Considerations ◽  
The Way

In the case of metric thread, a possible source of the flank error could be the position of the cutting tool edge, which could not intersect the circular cylindrical surface axis. An analytical method of approximation was applied to model the way in which the flank error is generated by considering some geometrical conditions. A theoretical simplified model was determined to highlight the influence of the thread external diameter and of the distance between the circular cylindrical surface axis and the thread rectilinear generatrix on the profile error of thread flank.

Force-Controlled Assembly of two Objects with a Two-arm Robot

Robotica ◽  
1991 ◽  
Vol 9 (3) ◽  
pp. 299-306 ◽  
Author(s):  
Pierre Dauchez ◽  
Xavier Delebarre
Keyword(s):  
Position Control ◽  
Hybrid Control ◽  
Contact Forces ◽  
Rigid Object ◽  
Assembly Task ◽  
Control Scheme ◽  
The One ◽  
Theoretical Results ◽  
Hybrid Control Scheme ◽  
Approach Phase

SUMMARYThe use of a two-arm robot for assembling two objects, with each being held by one arm, is presented. The assembly task is decomposed into an approach phase and an assembly phase. For each phase, we propose a solution for describing the task. For the approach phase, we suggest to describe the task with respect to a mobile reference frame, attached to the end effector of one of the arms. This allows us to take advantage of the redundancy of the system. For the assembly phase, we propose two solutions, both involving some kind of force control. The first one is based upon a position control similar to the one used for the approach phase, with an updating of the reference position through a measurement of the contact forces. The second scheme is derived from a symmetrical hybrid control scheme initially proposed by Uchiyama and Dauchez to control a two-arm robot handling a single rigid object. The main results of this scheme are summarized, and the way of using it for an assembly task is presented. Finally, the experimental setup we have installed to validate our theoretical results is described.

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