A Novel Region-Division-Based Tolerance Design Method for a Large Number of Discrete Elements Distributed on a Large Surface

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Guodong Sa ◽  
Zhenyu Liu ◽  
Chan Qiu ◽  
Jianrong Tan
Keyword(s):  
Phased Array ◽  
Design Method ◽  
Geometric Error ◽  
Product Performance ◽  
Tolerance Design ◽  
Geometric Errors ◽  
Discrete Elements ◽  
Sensitivity Matrix ◽  
Region Division ◽  
Main Components

The array structure is widely used in precise electronic products such as large phased array antennas and large optical telescopes, the main components of which are a large surface base and a large number of high-precision discrete elements mounted on the surface base. The geometric error of discrete elements is inevitable in the manufacturing process and will seriously degrade the product performance. To deal with the tolerance design of discrete elements, a region-division-based tolerance design method is proposed in this paper. The whole array was divided into several regions by our method and the tolerance of discrete elements was correlated with the region importance on the performance. The method specifically includes the following steps: first, the sensitivity of the product performance to geometric errors was analyzed and the statistical relationship between the performance and geometric errors was established. Then, based on the sensitivity matrix, the regional division scheme was developed, and the corresponding tolerance was optimized according to the established relationship function. Finally, the optimal tolerance was selected among the multiple solutions to achieve the best performance. Taking a large phased array as an example, a simulation experiment was performed to verify the effectiveness of the proposed method.

scholarly journals A Hybrid Tolerance Design Method for the Active Phased-Array Antenna

2020 ◽  
Vol 10 (4) ◽  
pp. 1435 ◽  
Author(s):  
Guodong Sa ◽  
Zhenyu Liu ◽  
Chan Qiu ◽  
Jianrong Tan
Keyword(s):  
Design Method ◽  
Array Antenna ◽  
Tolerance Design ◽  
Geometric Errors ◽  
Discrete Elements ◽  
Phased Array Antenna ◽  
Form Errors ◽  
Position Errors ◽  
Working Frequency ◽  
Effectiveness And Efficiency

With the increase of the working frequency of the array antenna, tolerance design has become increasingly important. The state-of-art tolerance design methods mainly deal with the position tolerance of the discrete elements. However, the geometric errors of the whole array have resulted from two aspects: (1) the position errors of the discrete elements and (2) the form errors of the continuous reflection plate. To optimize the position tolerance and flatness simultaneously, a hybrid tolerance design method is proposed. First, the relation between the performance of the array antenna and hybrid tolerances was determined based on the second order Taylor expansion. Then the expectation and variance of the performance were derived. Finally, the hybrid tolerances were optimized and the performance of the antenna was improved. Simulation results proved the effectiveness and efficiency of the proposed hybrid tolerance design method.

The Geometric Errors Identification of New Methods in Four-Axis Machining Center Axis

2012 ◽  
Vol 220-223 ◽  
pp. 348-354 ◽  
Author(s):  
Shuan Qiang Yang ◽  
Shu Wen Lin
Keyword(s):  
Geometric Error ◽  
Identification Accuracy ◽  
Geometric Errors ◽  
Sensitivity Matrix ◽  
Error Identification ◽  
Rotary Axes ◽  
Machining Center ◽  
Rational Distribution ◽  
Ball Bar ◽  
Center Axis

A method for fast measuring and identify the six geometric errors of each rotary axes in Four- axis machining center was invented. The method adopted the ball-bar to measure the X, Y, Z direction deviations of the centre block installed on the rotary table in the different rotation angle. And deduced the geometric error identification model in rotary axes based homogeneous transformation, and then identify the axis of the six basic geometric errors. in order to reduce the influence of the inaccuracy of the ball-bar and the reference point position, this paper put forward new method based on the analysis of the sensitivity matrix method, used to guide rational distribution points, so as to improve the error identification accuracy.

Novel Performance-Oriented Tolerance Design Method Based on Locally Inferred Sensitivity Analysis and Improved Polynomial Chaos Expansion

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Guodong Sa ◽  
Zhenyu Liu ◽  
Chan Qiu ◽  
Xiang Peng ◽  
Jianrong Tan
Keyword(s):  
Sensitivity Analysis ◽  
Surrogate Model ◽  
Polynomial Chaos ◽  
Design Method ◽  
Polynomial Chaos Expansion ◽  
Product Performance ◽  
Tolerance Design ◽  
Chaos Expansion ◽  
Performance Requirements ◽  
Electromechanical Products

Abstract Tolerance design is becoming increasingly important for electromechanical products. Reasonable tolerance design can reduce production costs and improve product performance. However, as the complexity of the coupling of tolerances and performance increases, it becomes difficult for designers to establish accurate tolerance design models, leading to experience-based design. This study proposes a novel performance-oriented tolerance design method. First, the main tolerance variables affecting the product performance are rapidly determined based on the proposed locally inferred sensitivity analysis method. Then, based on the improved approximate polynomial chaos expansion, a surrogate model of the product performance and main tolerance variables is established. Finally, the geometric tolerances of the electromechanical products are optimized based on the surrogate model with performance requirements. The proposed tolerance design method is computationally efficient and accurate, and it can be implemented with a small number of samples. To demonstrate its performance, the proposed method is validated with a spaceborne active-phased array antenna. The optimal tolerance design of the antenna for the electrical performance requirements is performed successfully.

Research on the Optimal Design Method of the Main Components for the Wheelchair Pickup

2013 ◽  
Vol 791-793 ◽  
pp. 799-802
Author(s):  
Ya Ping Wang ◽  
H.R. Shi ◽  
L. Gao ◽  
Z. Wang ◽  
X.Y. Jia ◽  
...  
Keyword(s):  
Parametric Design ◽  
Design Method ◽  
Basic Function ◽  
Design Parameters ◽  
Algorithm Optimization ◽  
Optimization Analysis ◽  
Research Designs ◽  
Optimal Design Method ◽  
Main Components

With the increasing of the aging of population all over the world, and With the inconvenience coming from diseases and damage, there will be more and more people using the wheelchair as a tool for transport. When it cant be short of the wheelchair in the daily life, the addition of the function will bring the elevation of the quality of life for the unfortunate. Staring with this purpose, the research designs a pickup with planetary bevel gear for the wheelchair. After determining the basic function of the wheelchair aids, the study determines the design parameters by using the knowledge of parametric design and completes the model for the system with Pro/E, on the other hand, it completes key components optimization analysis which is based on genetic algorithm optimization.

Modeling and Identification of Geometric Error Based on Screw Theory

2014 ◽  
Vol 941-944 ◽  
pp. 2219-2223 ◽  
Author(s):  
Guo Juan Zhao ◽  
Lei Zhang ◽  
Shi Jun Ji ◽  
Xin Wang
Keyword(s):  
Machine Tool ◽  
Laser Interferometer ◽  
Screw Theory ◽  
Geometric Error ◽  
New Method ◽  
Geometric Errors ◽  
Volumetric Error ◽  
B Spline ◽  
The Individual

In this paper, a new method is presented for the identification of machine tool component errors. Firstly, the Non-Uniform Rational B-spline (NURBS) is established to represent the geometric component errors. The individual geometric errors of the motion parts are measured by laser interferometer. Then, the volumetric error for a machine tool with three motion parts is modeled based on the screw theory. Finally, the simulations and experiments are conducted to confirm the validity of the proposed method.

Sensitivity Analysis of Geometric Errors for Five-Axis CNC Machine Tool Based on Multi-Body System Theory

2012 ◽  
Vol 271-272 ◽  
pp. 493-497
Author(s):  
Wei Qing Wang ◽  
Huan Qin Wu
Keyword(s):  
System Theory ◽  
Sensitivity Analysis ◽  
Machine Tool ◽  
Geometric Error ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Body System ◽  
Cnc Machine ◽  
Multi Body ◽  
Five Axis

Abstract: In order to determine that the effect of geometric error to the machining accuracy is an important premise for the error compensation, a sensitivity analysis method of geometric error is presented based on multi-body system theory in this paper. An accuracy model of five-axis machine tool is established based on multi-body system theory, and with 37 geometric errors obtained through experimental verification, key error sources affecting the machining accuracy are finally identified by sensitivity analysis. The analysis result shows that the presented method can identify the important geometric errors having large influence on volumetric error of machine tool and is of help to improve the accuracy of machine tool economically.

Research on the Conformal Phased-Array Antenna

2014 ◽  
Vol 685 ◽  
pp. 324-327
Author(s):  
Shuang Zhao ◽  
Yu Bo Yue
Keyword(s):  
Mathematical Model ◽  
Antenna Array ◽  
Phased Array ◽  
Design Method ◽  
Array Antenna ◽  
Phased Array Antenna ◽  
Conformal Antenna ◽  
Conformal Array ◽  
Design Requirements ◽  
The Mathematical Model

The mathematical model of conformal antenna array is the premise and basis of the conformal array antenna signal processing. Based on the analysis of the antenna array, a design method for adjusting the direction of the conformal array antenna is proposed. Through simulation, the pattern of antenna meets the actual needs of the project and it reaches pre design requirements.

Table-Based Volumetric Error Compensation of Large Five-Axis Machine Tools

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Jennifer Creamer ◽  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers ◽  
Philip L. Freeman ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Data Gathering ◽  
Measurement Data ◽  
Geometric Error ◽  
Compensation Method ◽  
Geometric Errors ◽  
Simultaneous Generation ◽  
Five Axis

This paper presents a geometric error compensation method for large five-axis machine tools. Compared to smaller machine tools, the longer axis travels and bigger structures of a large machine tool make them more susceptible to complicated, position-dependent geometric errors. The compensation method presented in this paper uses tool tip measurements recorded throughout the axis space to construct an explicit model of a machine tool's geometric errors from which a corresponding set of compensation tables are constructed. The measurements are taken using a laser tracker, permitting rapid error data gathering at most locations in the axis space. Two position-dependent geometric error models are considered in this paper. The first model utilizes a six degree-of-freedom kinematic error description at each axis. The second model is motivated by the structure of table compensation solutions and describes geometric errors as small perturbations to the axis commands. The parameters of both models are identified from the measurement data using a maximum likelihood estimator. Compensation tables are generated by projecting the error model onto the compensation space created by the compensation tables available in the machine tool controller. The first model provides a more intuitive accounting of simple geometric errors than the second; however, it also increases the complexity of projecting the errors onto compensation tables. Experimental results on a commercial five-axis machine tool are presented and analyzed. Despite significant differences in the machine tool error descriptions, both methods produce similar results, within the repeatability of the machine tool. Reasons for this result are discussed. Analysis of the models and compensation tables reveals significant complicated, and unexpected kinematic behavior in the experimental machine tool. A particular strength of the proposed methodology is the simultaneous generation of a complete set of compensation tables that accurately captures complicated kinematic errors independent of whether they arise from expected and unexpected sources.

Sign in / Sign up

Export Citation Format

Share Document