Evaluation of influence of target location on robot repeatability

Robotica ◽  
2000 ◽  
Vol 18 (4) ◽  
pp. 443-449 ◽  
Author(s):  
Raziel Riemer ◽  
Yael Edan
Keyword(s):  
Error Analysis ◽  
Target Location ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Experimental Results ◽  
Target Point ◽  
Analysis Model ◽  
Significant Statistical Difference ◽  
Optimal Target ◽  
Set Up

This paper evaluates the influence of target location on robot repeatability. An experiment was set up to analyze the effect of the three-dimensional target location on robot repeatability. An error-analysis model to determine repeatability based on the robot's kinematic model and known robot parameters was developed. Experimental results indicated that there was a significant statistical difference between repeatability at different locations in the workspace and that the height of the target point influenced repeatability. Experimental results tended to those derived from the error-analysis kinematic model. Hence, to determine the optimal target location, there is no need for extensive experimentation; instead, only a few target points can be sampled and compared to an error-analysis model.

Fabrication of a piezoelectrically driven micropositioning 3-DOF stage with elastic body using a multi-material 3D printer

2020 ◽  
Vol 26 (9) ◽  
pp. 1579-1591
Author(s):  
Sang-Woo Baek ◽  
Nahm-Gyoo Cho ◽  
Dong-Hyeok Lee
Keyword(s):  
Elastic Body ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Experimental Results ◽  
Analysis Model ◽  
Content Type ◽  
Vision Measurement ◽  
Conventional Material ◽  
Single Material

Purpose This paper aims to propose a method for manufacturing multi-material monolithic structures with flexible materials to construct the elastic body by using a dual-nozzle three-dimensional printer to develop a piezoelectric (PZT)-driven micropositioning stage with three degrees of freedom (3-DOF) and flexure hinges. Design/methodology/approach Polylactic acid (PLA) and nylon were used for the lever structure’s frame and flexure hinge, respectively. Additionally, the stage consisted of three PZT actuators for fine movement in the nanometer scale in 3-DOF (x, y and θ-directions). For the design of the stage, the kinematic analysis model and the finite element method (FEM) analysis was undertaken for comparing between PLA with nylon (multi-material), PLA (single material) and aluminum (conventional-material). In addition, two verification experiments were implemented for the fabricated prototype stage. First, to evaluate various assessments (lever ratio, hysteresis, coupling error and resolution), a measurement is carried out using the three capacitive sensors. Then, a two-camera-vision measurement experiment was performed to verify the displacement and lever ratio over the full-scale working range of the fabricated positioning stage, and the results from the experimentation and the FEM analysis were compared. Findings The authors confirmed enhancements in the properties of the lever structure frame, which requires stiffness and of the hinge, which requires flexibility for elastic deformation. Comparing FEM analysis and experimental results, although the performance as shown by experimental results was lower: the maximum difference being 3.4% within the end-point working range; this difference was sufficient to be a plausible alternative for the aluminum-based stage. Originality/value Multi-material monolithic-structure fabrication has an effective advantage in improving the performance of the stage, by using a combination of materials capable of reinforcing the desired characteristics in the necessary parts. It was verified that the fabricated stage can substitute the aluminum-based stage and can achieve a higher performance than single-material stages. Thus, precise-positioning stages can be manufactured in many kinds of structures with various properties and contribute to weight reduction and low costs for application equipment.

scholarly journals The Design of Compact Robotic-Assisted Needle Position System with MPC-Based Remote Control

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jing Guo ◽  
Yi Liu ◽  
Jin Wang ◽  
Chao Zeng ◽  
Jie Huang ◽  
...  
Keyword(s):  
Control Method ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Percutaneous Biopsy ◽  
Target Point ◽  
Model Parameters ◽  
Control Input ◽  
Control Performance ◽  
Robot System ◽  
Needle Position

This article introduces the design and control performance of a lightweight, flexible, 4-degree-of-freedom (DOF) parallel robot for percutaneous biopsy guided by computed tomography (CT). At present, the CT guidance method allows surgeons to quickly locate the lesion area; however, it is necessary to manually adjust the position of the puncture needle for insertion. In this paper, a three-dimensional assisted method is used to infer the control input required to reach the target point through the kinematic model of the robot. A Kalman filter is designed to estimate model parameters and obtain a more accurate model. To further improve the control performance of the robot system, a model-based control method—the model predictive control (MPC) controller—is used to increase the accuracy of the needle position in the developed robot system. In this way, medical efficiency is improved while reducing the burden on the surgeon.

Influence of Beam Polarizations on Evaporative Laser Cutting Nonmetallic Materials within High Absorptance

2009 ◽  
Vol 626-627 ◽  
pp. 363-368
Author(s):  
Xiao Zhu Xie ◽  
J.G. Lu ◽  
Xin Wei ◽  
W. Hu
Keyword(s):  
Theoretical Analysis ◽  
Laser Beam ◽  
Ray Tracing ◽  
Laser Cutting ◽  
Three Dimensional ◽  
Coupling Model ◽  
Experimental Results ◽  
Multiple Reflections ◽  
Set Up ◽  
Tracing Method

The three dimensional (3D) coupling model is set up for analyzing the energy reflection and absorption on the kerf using ray tracing method after the laser beam cutting nonmetallic materials with high absorptance through multiple reflections. The laser beam characterized by focused gauss beam and fresnel absorption on the kerf are taken into account. The influences of the polarization on the absorbed intensity both in the front and the two walls are also discussed. Results indicate the differences of absorptive intensity among the three polarized lights are relatively small compared to metal. Thus, the polarization has little effects on the kerf of nonmetallic materials with high absorptance. The experimental results also agree well with the theoretical analysis.

New Groove Design and Three-Dimensional Numerical Simulation of Ultra-Fine Grain of Bar Rolling

2012 ◽  
Vol 581-582 ◽  
pp. 879-882
Author(s):  
Lei Cao ◽  
Xue Tong Li ◽  
Shu Jian Liu ◽  
Min Ting Wang
Keyword(s):  
Plastic Strain ◽  
Cross Section ◽  
Design Method ◽  
Three Dimensional ◽  
Rolling Process ◽  
Analysis Model ◽  
Bar Rolling ◽  
Groove Design ◽  
Fine Grain ◽  
Set Up

A new groove design method of uniform strong strain of bar rolling was proposed based on the principle of strong plastic deformation to manufacture ultra-fine grain(UFG), and flat-oval groove type with the characteristics of big crushed and multidirectional deformation was set up. The numerical analysis model of hot continuous bar rolling process was created using nonlinear finite element method. The study of the law of plastic strain distribution after each rolling pass of the caliber series indicated that the caliber can satisfy with the precise size and shape, and can also better introduce the plastic strain to the center of cross section and get uniform strong strain. The largest strain was more than 5.0 in the center of cross section, in which condition ultra-fine grain can be fabricated. Therefore, this study provides important theoretical basis for the ultra-fine grain of bar rolling development.

A Comprehensive Error Analysis Method for Accuracy Reliability Deployment

2016 ◽  
Vol 13 (10) ◽  
pp. 7271-7279
Author(s):  
Lei Du ◽  
Jianmin Gao ◽  
Kun Chen
Keyword(s):  
Error Analysis ◽  
Quality Function Deployment ◽  
Fault Tree Analysis ◽  
Reliability Function ◽  
Geometric Error ◽  
Numerical Control ◽  
Analysis Model ◽  
Set Up ◽  
Criticality Analysis ◽  
Deformation Error

To avoid equipment accuracy failure caused by degradation with use, the concept of Reliability Function Deployment (RFD) is employed to set up a comprehensive error analysis model. An operative matrix tool, called the House of Accuracy Reliability (HoAR) is presented. The HoAR is combined with Fault Tree Analysis (FTA), Failure Mode Effects and Criticality Analysis (FMECA) and Quality Function Deployment (QFD). In the HoAR, besides geometric error, thermal deformation error and load deformation error, a domino effect of error propagation is also taken into account for the risk assessment. Using the results from the HoAR, a comprehensive error analysis can be easily performed, making it possible to identify the significant accuracy parameters and compensate for the accuracy losses. Tests on a numerical control lathe are carried out to validate the proposed model and method.

Design of Three-Dimensional Wireless Power Receiving Coil for MEMS

2011 ◽  
Vol 383-390 ◽  
pp. 5569-5575
Author(s):  
Yang Li ◽  
Kai Feng Xue ◽  
Huang Ping
Keyword(s):  
Three Dimensional ◽  
Experimental Results ◽  
Coupling Coefficients ◽  
Wireless Power ◽  
Practical Application ◽  
Camera System ◽  
Actual Output ◽  
Receiving Coil ◽  
System Energy ◽  
Set Up

In this paper, a micro three-dimensional wireless power receiving coil is designed and powered by a set up wireless energy transmission system. Energy receiving performances of the receiving coil is studied. By experiments, coupling coefficients between the transmitting coil and each winding of the receiving coil are caculated at different attitudes. The experimental results confirm that the receiving coil can receive energy from three orientations and three orthometric windings can compensate each other effectively at different attitudes. Then a micro rectifier and regulator circuit are designed and fabricated which is used for a self-made camera system. Based on this, the actual output voltage is measured. The experimental results verify that the efficiency and stability of the three-dimensional receiving system can meet practical application.

Modeling and experimental verification on directivity of an electret cell array loudspeaker

2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Digital Control System ◽  
Analysis Model ◽  
Cell Array ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Directivity Characteristics

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

Optimum Design for the Frame of Open Type Abrasive Flow Polish Machine

2012 ◽  
Vol 497 ◽  
pp. 89-93
Author(s):  
Liang Liang Yuan ◽  
Ke Hua Zhang ◽  
Li Min
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Finite Element Methods ◽  
Optimization Design ◽  
Low Cost ◽  
Three Dimensional ◽  
Force Model ◽  
Optimization Analysis ◽  
Open Type ◽  
Set Up

In order to process heterotype hole of workpiece precisely, an open abrasive flow polish machine is designed, and the optimization design of machine frame is done for low cost. Firstly, basing on the parameters designed with traditional ways, three-dimensional force model is set up with the soft of SolidWorks. Secondly, the statics and modal analysis for machine body have been done in Finite element methods (FEM), and then the optimization analysis of machine frame has been done. At last, the model of rebuild machine frame has been built. Result shows that the deformation angle value of machine frame increased from 0.72′ to 1.001′, the natural frequency of the machine decreased from 75.549 Hz to 62.262 Hz, the weight of machine decreased by 74.178 Kg after optimization. It meets the strength, stiffness and angel stiffness requirement of machine, reduces the weight and cost of machine.

Conical SNA using fuzzy k-medoids based on user experience

2021 ◽  
pp. 002072092098849
Author(s):  
Poonam Rani ◽  
MPS Bhatia ◽  
Devendra K Tayal
Keyword(s):  
Social Networks ◽  
Social Network ◽  
User Experience ◽  
Three Dimensional ◽  
Experimental Results ◽  
Dynamic Parameters ◽  
Clustering Method ◽  
Cone Model ◽  
Intelligent Approach ◽  
Conical Model

The paper presents an intelligent approach for the comparison of social networks through a cone model by using the fuzzy k-medoids clustering method. It makes use of a geometrical three-dimensional conical model, which astutely represents the user experience views. It uses both the static as well as the dynamic parameters of social networks. In this, we propose an algorithm that investigates which social network is more fruitful. For the experimental results, the proposed work is employed on the data collected from students from different universities through the Google forms, where students are required to rate their experience of using different social networks on different scales.

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