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.

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.

Toward the Accurate Coverage of Aspheric Surfaces Using Two-Dimensional Scanning Paths for Minimizing Regular Errors

2007 ◽  
Vol 364-366 ◽  
pp. 64-68
Author(s):  
Hao Bo Cheng ◽  
Jing Feng Zhi ◽  
Yong Tian Wang ◽  
Jing Bian
Keyword(s):  
Path Planning ◽  
Material Removal ◽  
Tool Path ◽  
Two Dimensional ◽  
Tool Path Planning ◽  
Aspheric Surfaces ◽  
Neuro Fuzzy ◽  
Planning Algorithm ◽  
Path Planning Algorithm ◽  
Error Removal

This paper describes a two-dimensional tool-path planning model for minimizing the regularly distributed errors or mid-frequency errors during computer controlled optical surfacing (CCOS) by optimally connecting different tool-path segments. The model was established based on a neuro-fuzzy algorithm, a path neighborhood function which is defined as a victorious output element calculated in a self-organization way, then, the optimum material removal function with a modified weight was derived. The material removal function was studied theoretically and the results of simulation present a Gaussian distribution feature. Discrete removal points and optimized tool-path grid were simulated. Finally, an experiment involving a parabolic mirror was performed for residual error removal and the two-dimensional tool-path planning algorithm was found to be valid.

Stochastic Fractal Modeling and Process Planning for Machining Using Two-Dimensional Iterated Function System

2008 ◽  
Vol 392-394 ◽  
pp. 575-579
Author(s):  
Yu Hao Li ◽  
Jing Chun Feng ◽  
Y. Li ◽  
Yu Han Wang
Keyword(s):  
Path Planning ◽  
Tool Path ◽  
Iterated Function System ◽  
Numerical Control ◽  
Function System ◽  
Tool Path Planning ◽  
Ongoing Research ◽  
Iterated Function ◽  
Planning Algorithm ◽  
Path Planning Algorithm

Self-affine and stochastic affine transforms of R2 Iterated Function System (IFS) are investigated in this paper for manufacturing non-continuous objects in nature that exhibit fractal nature. A method for modeling and fabricating fractal bio-shapes using machining is presented. Tool path planning algorithm for numerical control machining is presented for the geometries generated by our fractal generation function. The tool path planning algorithm is implemented on a CNC machine, through executing limited number of iteration. This paper describes part of our ongoing research that attempts to break through the limitation of current CAD/CAM and CNC systems that are oriented to Euclidean geometry objects.

A genetic path planning algorithm for redundant articulated robots

Robotica ◽  
1997 ◽  
Vol 15 (2) ◽  
pp. 213-224 ◽  
Author(s):  
Andreas C. Nearchou ◽  
Nikos A. Aspragathos
Keyword(s):  
Path Planning ◽  
Degrees Of Freedom ◽  
Target Location ◽  
Planning Problem ◽  
Worst Case ◽  
Pick And Place ◽  
Planning Algorithm ◽  
A New Technique ◽  
Articulated Robots ◽  
Path Planning Algorithm

In some daily tasks, such as pick and place, the robot is requested to reach with its hand tip a desired target location while it is operating in its environment. Such tasks become more complex in environments cluttered with obstacles, since the constraint for collision-free movement must be also taken into account. This paper presents a new technique based on genetic algorithms (GAs) to solve the path planning problem of articulated redundant robot manipulators. The efficiency of the proposed GA is demonstrated through multiple experiments carried out on several robots with redundant degrees-of-freedom. Finally, the computational complexity of the proposed solution is estimated, in the worst case.

An Algorithm of Non-Iso Parameters Cutting Path Planning Using Toroid Cutter

2013 ◽  
Vol 373-375 ◽  
pp. 2088-2091
Author(s):  
Quan Liang ◽  
Dong Hai Su ◽  
Jie Wang ◽  
Ye Mu Wang
Keyword(s):  
Path Planning ◽  
Trajectory Planning ◽  
Tool Path ◽  
Search Algorithm ◽  
Free Form ◽  
Processing Efficiency ◽  
Planning Algorithm ◽  
Path Planning Algorithm ◽  
Five Axis ◽  
Cutting Path

For the problem of poor processing efficiency of iso-parameter tool path planning algorithm, this paper proposed a non iso-parameter trajectory planning algorithm. First established a mathematical model of five-axis machining toroid cutter, then analyzed the toroid cutter and machining surface partial differential geometric properties, proposed one kind of iso-scallop path search algorithm. Finally, using the above algorithm developed an application of trajectory planning for free-form surface and generated tool paths for such surface. The trajectories generated verified the algorithm is practicable.

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