The Control Algorithm of Ultrasonic-Magnetorheological Combined Finishing for Rotary Symmetrical Aspheric Surface

2010 ◽  
Vol 97-101 ◽  
pp. 2099-2102
Author(s):  
Fei Hu Zhang ◽  
Xing Bin Yu ◽  
Yong Zhang ◽  
Yong Yong Lin ◽  
Dian Rong Luan
Keyword(s):  
Computer Simulation ◽  
Dwell Time ◽  
Control Algorithm ◽  
Curvature Radius ◽  
Aspheric Surface ◽  
Ultraprecision Machining ◽  
Freeform Surfaces ◽  
Aspheric Surfaces ◽  
A New Technique ◽  
Derivation Process

Concave aspheric surface with small curvature radius is difficult to fabricate by most of existing technologies. Ultrasonic- magnetorheological combined finishing (UMC) is a new technique for the ultraprecision machining of aspheric surfaces, especially for the ultrasmooth surfaces machining of small-radiuses concave surfaces and freeform surfaces. According to the characteristics of rotary symmetrical aspheric surface, path algorithms for UMC finishing have been developed. Propose and compare two kinds of polishing dwell time algorithms, and the derivation process and computer simulation result of the algorithms was also presented. The experiments using the control algorithm have been conducted, and the efficiency of algorithm is proved by experimental results.

Research on a Colloid Jet Polishing Equipment and its NC Interpolation Algorithm for Rotary Symmetric Aspheric

2009 ◽  
Vol 416 ◽  
pp. 497-503
Author(s):  
Yong Zhang ◽  
Qing Quan Zhang ◽  
Xiao Zong Song ◽  
Guang Yu Zhang ◽  
Fei Hu Zhang
Keyword(s):  
Surface Roughness ◽  
Computer Simulation ◽  
Calculation Formula ◽  
Interpolation Algorithm ◽  
Ultraprecision Machining ◽  
High Quality ◽  
Aspheric Surfaces ◽  
A New Technique ◽  
K9 Glass ◽  
Derivation Process

Colloid jet polishing (CJP) is a new technique for the ultraprecision machining of aspheric surfaces, especially for the ultrasmooth surfaces machining of small-radiused concave surfaces and freeform surfaces. In this paper, a colloid jet polishing equipment with 5 axes, four of which perform linkage movement was developed. According to characteristic of colloid jet polishing, NC interpolation algorithm for rotary symmetric aspheric based on this equipment was researched. The derivation process and computer simulation result of the algorithm was also presented. The interpolation error of this algorithm was analyzed and the calculation formula was also proposed. According to the result of analysis, the precision of the interpolation algorithm is high and the algorithm is very useful. Experiments show that high quality ultrasmooth surface can be achieved using this method and surface roughness Ra less than 1nm for K9 glass can be obtained stably.

Polyline Dwell Time Algorithm for Every Type of Tool Path for Ultrasonic-Magnetorheological Combined Finishing

2010 ◽  
Vol 126-128 ◽  
pp. 435-440
Author(s):  
Fei Hu Zhang ◽  
Xing Bin Yu ◽  
Yong Zhang ◽  
Yong Yong Lin
Keyword(s):  
Dwell Time ◽  
Tool Path ◽  
Time Algorithm ◽  
Mean Value ◽  
Curvature Radius ◽  
Aspheric Surfaces ◽  
Planning Algorithm ◽  
Material Removal Model ◽  
A New Technique ◽  
Path Planning Algorithm

Ultrasonic- magnetorheological combined finishing (UMC) is a new technique for the ultraprecision machining of aspheric surfaces, especially for high quality workpieces with small curvature radius concave surfaces. According to the characteristics of UMC finishing, material removal model has been developed. Several types of tool path planning algorithm have been discussed. Two kinds of polyline dwell time algorithm are presented. Polyline Dwell time algorithm based on two-dimensional discrete convolution is a new dwell time algorithm, and the dwell time on the endpoints which compose the tool path can be solved by the algorithm directly. Every polyline dwell time is the mean value of dwell time of two endpoints, therefore, the polyline dwell time of every type of tool path can be solved efficiently by the algorithm. The simulation of two dwell time algorithms has been conducted with same removal function and original error distribution, and the pv convergence rate is improved from 0.939 to 0.973 by using new algorithm. Figure error PV values reduced to 29.4 nm from 1.67μm after UMC finishing. The efficiency of the polyline dwell algorithm is proved by computer simulation and experimental results.

Analysis of Tangential Position Error or Removal Function Error in Ultrasonic-Magnetorheological Combined Finishing

2012 ◽  
Vol 516 ◽  
pp. 390-395
Author(s):  
Fei Hu Zhang ◽  
Xing Bin Yu ◽  
Yong Zhang
Keyword(s):  
Tool Path ◽  
Current Approach ◽  
Residual Error ◽  
Curvature Radius ◽  
Aspheric Surfaces ◽  
Form Errors ◽  
Positioning Errors ◽  
Ultra Precision ◽  
A New Technique ◽  
Low Amplitude

Ultrasonic-magnetorheological combined finishing (UMCF) is a new technique for the ultra precision machining of aspheric surfaces, especially for high quality work pieces with small curvature radius concave surfaces. The goal with UMCF is to minimize surface figure errors by optimizing the dwell time and tool path, and the current approach typically results in low amplitude form errors. However, discrepancies exist between the predicted and observed form errors. The major sources of such errors are machine axes positioning errors and unpredicted variations of the removal function. Errors that can produce discrepancies between actual and predicted removal profiles were modelled. A diagnostic method was developed to determine the residual error induced by two types of error. Their effects were examined with numerical simulations and the simulation result was presented. Finally, UMCF experiments are performed on a variety of optical surfaces. The final residual error after polishing is less than 2.6 nm PV values. The successful figuring results prove the validity and advantages of UMCF.

scholarly journals On the Practical Stability of Hybrid Control Algorithm With Minimum Dwell Time for a DC–AC Converter

2019 ◽  
Vol 27 (6) ◽  
pp. 2581-2588 ◽  
Author(s):  
Carolina Albea Sanchez ◽  
Oswaldo Lopez Santos ◽  
David. A. Zambrano Prada ◽  
Francisco Gordillo ◽  
Germain Garcia
Keyword(s):  
Dwell Time ◽  
Control Algorithm ◽  
Hybrid Control ◽  
Practical Stability

Fundamental Investigation on the Polishing Aspheric Elements with Doughnut-Shaped MCF Slurry

2018 ◽  
Vol 792 ◽  
pp. 179-184 ◽  
Author(s):  
Ming Feng ◽  
Yong Bo Wu ◽  
Teruo Bitoh ◽  
Tsunehisa Suzuki ◽  
Mitsuyoshi Nomura ◽  
...  
Keyword(s):  
Experimental Result ◽  
Aspheric Surface ◽  
Aspheric Surfaces ◽  
Variable Parameters ◽  
Flat Surfaces ◽  
Surface Polishing ◽  
Fundamental Investigation ◽  
Novel Method ◽  
Curve Radius ◽  
Polishing Tool

Previous researches have confirmed that MCF (magnetic compound fluid) slurry shows outstanding performance in the nanoprecision polishing of flat surfaces and V-grooves. However, no investigations have been conducted on the polishing of aspheric surfaces using MCF slurry. In this work, a novel method employing a doughnut-shaped MCF polishing tool and a 6-DOF manipulator has been proposed for the aspheric surface polishing. The time consumption for forming stable polishing tool and its final appearance are investigated. Flat aluminum alloy workpieces that can be considered as a kind of aspheric elements with infinite curve radius were adopted in the investigation of the polished forces under variable parameters. As a typical experimental result, with MCF3 slurry, 2.5ml volume of supplied slurry and work gap 3.5 mm, the surface roughness Ra decreases from 125nm to almost 10nm after 90 min polishing, confirming that the proposed method has the potential to polish aspheric surfaces.

scholarly journals Active optics in astronomy – modeling of deformable substrates: freeform surfaces for FIREBall and MESSIER

2018 ◽  
Vol 27 (5-6) ◽  
Author(s):  
Gérard Rene Lemaitre
Keyword(s):  
Adaptive Optics ◽  
Large Scale ◽  
Wide Field ◽  
Freeform Surfaces ◽  
Aspheric Surfaces ◽  
Massive Black Holes ◽  
Active Optics ◽  
Minimum Number ◽  
Co Addition ◽  
Large Telescopes

AbstractActive optics techniques on large telescopes and astronomical instrumentations provide high imaging quality. For ground-based astronomy, the co-addition of adaptive optics again increases angular resolution up to providing diffraction-limited imaging at least in the infrared. Active and adaptive optics marked milestone progress in the detection of exoplanets, super-massive black holes, and large-scale structure of galaxies. This paper is dedicated to highly deformable active optics that can generate non-axisymmetric aspheric surfaces – or freeform surfaces – by use of a minimum number of actuators: a single uniform load acts over the surface of a vase-form substrate whilst under reaction to its elliptical perimeter ring. Two such instruments are presented: (1) the Faint Intergalactic Redshifted Emission Balloon (FIREBall) telescope and multi object spectrograph (MOS) where the freeform reflective diffraction grating is generated by replication of a deformable master grating, and (2) the MESSIER wide-field low-central-obstruction three-mirror-anastigmat (TMA) telescope proposal where the freeform mirror is generated by stress figuring and elastic relaxation. Freeform surfaces were obtained by plane super-polishing. Preliminary analysis required use of the optics theory of 3rd-order aberrations and elasticity theory of thin elliptical plates. Final cross-optimizations were carried out with Zemax raytracing code and Nastran FEA elasticity code in order to determine geometry of the deformable substrates.

On-machine truing of diamond wheel and high-efficiency grinding of monocrystal silicon for aspheric surface

2016 ◽  
Vol 231 (1) ◽  
pp. 186-192 ◽  
Author(s):  
Bing Chen ◽  
Bing Guo ◽  
Qingliang Zhao
Keyword(s):  
Surface Quality ◽  
Material Removal ◽  
High Efficiency ◽  
Diamond Wheel ◽  
Experimental Results ◽  
Aspheric Surface ◽  
Removal Rates ◽  
Aspheric Surfaces ◽  
Silicon Carbon

To realize the high-efficiency grinding of the aspheric surfaces on monocrystal silicon, a novel on-machine truing method for the resin-bonded arc-shaped diamond wheels was proposed utilizing rotary green silicon carbon rod, and then the high-efficiency grinding of the aspheric surface was performed. First, the principle of mutual-wear for truing arc-shaped diamond wheel was introduced, and the truing performance was studied. The experimental results showed that the top morphology of the trued arc-shaped wheel was precise and smooth, and the run error on the top of the trued arc-shaped wheel was reduced from 41 to 10 µm after truing. Furthermore, high-efficiency grinding experiments revealed that the surface quality of the aspheric surface increased with the increase in the average material removal rates.

Sign in / Sign up

Export Citation Format

Share Document