A Generic Method to Generate AS-Curve Profile in Commercial Motion Controller

2017 ◽  
Author(s):  
Youdun Bai ◽  
Xin Chen ◽  
Zhijun Yang
Keyword(s):  
Motion Controller ◽  
Residual Vibration ◽  
Practical Applications ◽  
Analytic Polynomial ◽  
Acceleration And Deceleration ◽  
Special Knowledge ◽  
Curve Profile ◽  
S Curve ◽  
Motion Profile ◽  
Better Than

It is well believed that S-curve motion profiles are able to reduce residual vibration, and are widely applied in the motion control fields. Recently, a new asymmetric S-curve (AS-curve) motion profile, which is able to effectively adjust the acceleration and deceleration periods, is proposed to enhance the performance of S-curve motion profile, and proved to be better than the traditional symmetric S-curve in many cases. However, most commercial motion controllers do not support the AS-curve motion profiles inherently. Special knowledge or expensive advanced controlling systems, such as dSPACE system, are required to generate the AS-curve motion command, which limits the applications of the AS-curve motion profile in many practical applications. In this paper, a generic method based on the Position-Velocity-Time (PVT) mode move supported by most commercial motion controllers is proposed to generate exact AS-curve motion command in real machines. The analytic polynomial functions of AS-curve motion profile are also derived to simplify the further application, and the effectiveness of the proposed method is verified by numerical simulation.

scholarly journals Online-Offline Optimized Motion Profile for High-Dynamic Positioning of Ultraprecision Dual Stage

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Yang Liu ◽  
Yue Dong ◽  
Jiubin Tan
Keyword(s):  
Model Identification ◽  
Direct Drive ◽  
Motion Platform ◽  
Residual Vibration ◽  
Dual Stage ◽  
Stage System ◽  
Curve Profile ◽  
High Dynamic ◽  
S Curve ◽  
Motion Profile

The wafer stage in dual-stage lithographic system is an air-bearing servo motion platform requiring high positioning accuracy and high transient performance. However, the residual vibration, resulting from almost zero damping, high velocity, parallel decoupling structure, and direct drive, brings about unacceptable overshoot and settling time. To suppress these unfavorable elements in high dynamic motion, a novel motion profile planning method combined with input shaping is proposed in this paper. Firstly, a trajectory named all free S-curve (AFS-curve) is derived, which has less constraints and better performance than traditional S-curve profile. Then, AFS-curve combined with a zero vibration shaper (ZV) is developed to further suppress residual vibration. Due to the very complex parameter adjustment, the online tuning may cause system oscillation that leads to damage of the precision stage. This paper, furthermore, proposes an online-offline method to optimize the parameters in the motion profile. Online step is performed to collect input and output data. Offline step includes the system model identification based on I/O data and parameter self-learning based on particle swarm optimization (PSO). The simulation and experimental results indicate that the proposed method achieves significant reduction of the positioning time and the overshoot in the dual-stage system.

scholarly journals Zero Placement of the Asymmetric S-curve Profile to Minimize the Residual Vibration

2012 ◽  
Vol 18 (4) ◽  
pp. 308-313 ◽  
Author(s):  
Chang-Wan Ha ◽  
Keun-Ho Rew ◽  
Kyung-Soo Kim ◽  
Soo-Hyun Kim
Keyword(s):  
Residual Vibration ◽  
Curve Profile ◽  
S Curve

Realization of Target Position Changing On-The-Fly for Intelligent Motion Control Applications

2012 ◽  
Vol 271-272 ◽  
pp. 1602-1607
Author(s):  
Yi Zong Lai ◽  
Feng Ye ◽  
Wei Na Chen
Keyword(s):  
High Performance ◽  
Target Position ◽  
Motion Controller ◽  
Product Lines ◽  
Processing Application ◽  
Velocity Planning ◽  
Curve Profile ◽  
Speed Change ◽  
S Curve ◽  
Smooth Acceleration

This paper presents an algorithm of S-curve profile velocity planning with prediction of deceleration distance dynamically, extended functions including target position or target speed change on-the-fly, motion pausing and resuming are addressed. The algorithm is implemented for high performance multiple axes motion controller where complex paths must be employed for each axis to obtain smooth acceleration, speed, position shapes and target position or speed will be changed during moving to meet the requirement of processing. Application that requires the ability to change the endpoint or moving speed without completing the previous move are applied in varied industrial equipment such as SMT, AOI, product lines, etc.

The Applied Research of Four Polynomial Acceleration and Deceleration Control Method in Multi-Axis DSP Motion Controller

2012 ◽  
Vol 542-543 ◽  
pp. 567-572
Author(s):  
Jing Zhang ◽  
Wei Qiang Gao ◽  
Ze Hua Hu ◽  
Xiu Wen Huang ◽  
Jun Hua Song
Keyword(s):  
Applied Research ◽  
Control Method ◽  
Floating Point ◽  
Milling Machine ◽  
Control Methods ◽  
Motion Controller ◽  
Linear Index ◽  
Acceleration And Deceleration ◽  
Polynomial Acceleration ◽  
S Curve

In traditional NC systems, the linear, index and S curve acceleration and deceleration control methods exist lots of problems that jerk is discontinuous or algorithm is too complex, seeking a more superior acceleration and deceleration control method to make up these shortages is needed. In this paper, the Four polynomial acceleration and deceleration control method is researched further, some contrast experiments have been done on NC terrace which is based on 32 bit floating point multi-axis DSP motion controller, and the superiority of this method and the practicability in NC field are analysed by processing two hemispheres with H600 CNC engraving and milling machine.

Resolution and measurement in the scanning electron microscope

1987 ◽  
Vol 45 ◽  
pp. 534-537 ◽  
Author(s):  
Michael T. Postek
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Engineering Design ◽  
Resolving Power ◽  
Practical Applications ◽  
Instrument Resolution ◽  
Accurate Definition ◽  
Definition Of ◽  
Scanning Electron ◽  
Better Than

The term ultimate resolution or resolving power is the very best performance that can be obtained from a scanning electron microscope (SEM) given the optimum instrumental conditions and sample. However, as it relates to SEM users, the conventional definitions of this figure are ambiguous. The numbers quoted for the resolution of an instrument are not only theoretically derived, but are also verified through the direct measurement of images on micrographs. However, the samples commonly used for this purpose are specifically optimized for the measurement of instrument resolution and are most often not typical of the sample used in practical applications.SEM RESOLUTION. Some instruments resolve better than others either due to engineering design or other reasons. There is no definitively accurate definition of how to quantify instrument resolution and its measurement in the SEM.

A New Protocol for Secure Distributed Multiplication of Two Polynomial Shared Values

2014 ◽  
Vol 1042 ◽  
pp. 110-116
Author(s):  
Xiang Ning Hao ◽  
Xue Min Wang ◽  
Li Qiong Deng
Keyword(s):  
Secret Sharing ◽  
Shared Values ◽  
Secret Sharing Scheme ◽  
Threshold Secret Sharing ◽  
Practical Applications ◽  
Classic Problem ◽  
Sharing Scheme ◽  
Better Than

In view of practical applications, it is a high priority to optimize the efficiency of methods for secure multi-party computations. A classic problem is described as following: there are two secrets, α and β, shared among n players using Shamir (t+1,n)-threshold secret sharing scheme, and how to make their product αβshared among n players using the same way. The protocol of Gennaro, Rabin and Rabin (1998) is a well known and efficient protocol for this purpose. It requires one round of communication and O(n2klog2n+nk2) bit-operations per player, where k is the bit size of the computing field and n is the number of players. In a previous paper (2007), the author presented a modification of this protocol, which reduced its complexity toOn2k+nk2. In 2009, Peter Lory reduced its complexity to On2k. A new protocol is presented in our paper, which reduces this complexity further to Onklog2k. It is better than Gennaro protocol unconditionally. And as to Peter Lory protocol, the reduction is profitable in situation where log2k is smaller than n.

scholarly journals Endmember Learning with K-Means through SCD Model in Hyperspectral Scene Reconstructions

2019 ◽  
Vol 5 (11) ◽  
pp. 85 ◽  
Author(s):  
Ayan Chatterjee ◽  
Peter W. T. Yuen
Keyword(s):  
Dictionary Learning ◽  
Sparse Coding ◽  
Clustering Algorithm ◽  
Matching Pursuit ◽  
Orthogonal Matching Pursuit ◽  
Scene Reconstruction ◽  
Data Sets ◽  
Practical Applications ◽  
Input Dataset ◽  
Better Than

This paper proposes a simple yet effective method for improving the efficiency of sparse coding dictionary learning (DL) with an implication of enhancing the ultimate usefulness of compressive sensing (CS) technology for practical applications, such as in hyperspectral imaging (HSI) scene reconstruction. CS is the technique which allows sparse signals to be decomposed into a sparse representation “a” of a dictionary D u . The goodness of the learnt dictionary has direct impacts on the quality of the end results, e.g., in the HSI scene reconstructions. This paper proposes the construction of a concise and comprehensive dictionary by using the cluster centres of the input dataset, and then a greedy approach is adopted to learn all elements within this dictionary. The proposed method consists of an unsupervised clustering algorithm (K-Means), and it is then coupled with an advanced sparse coding dictionary (SCD) method such as the basis pursuit algorithm (orthogonal matching pursuit, OMP) for the dictionary learning. The effectiveness of the proposed K-Means Sparse Coding Dictionary (KMSCD) is illustrated through the reconstructions of several publicly available HSI scenes. The results have shown that the proposed KMSCD achieves ~40% greater accuracy, 5 times faster convergence and is twice as robust as that of the classic Spare Coding Dictionary (C-SCD) method that adopts random sampling of data for the dictionary learning. Over the five data sets that have been employed in this study, it is seen that the proposed KMSCD is capable of reconstructing these scenes with mean accuracies of approximately 20–500% better than all competing algorithms adopted in this work. Furthermore, the reconstruction efficiency of trace materials in the scene has been assessed: it is shown that the KMSCD is capable of recovering ~12% better than that of the C-SCD. These results suggest that the proposed DL using a simple clustering method for the construction of the dictionary has been shown to enhance the scene reconstruction substantially. When the proposed KMSCD is incorporated with the Fast non-negative orthogonal matching pursuit (FNNOMP) to constrain the maximum number of materials to coexist in a pixel to four, experiments have shown that it achieves approximately ten times better than that constrained by using the widely employed TMM algorithm. This may suggest that the proposed DL method using KMSCD and together with the FNNOMP will be more suitable to be the material allocation module of HSI scene simulators like the CameoSim package.

scholarly journals Trapezoidal Motion Profile to Suppress Residual Vibration of Flexible Object Moved by Robot

Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 30 ◽  
Author(s):  
Hyun Joong Yoon ◽  
Seong Youb Chung ◽  
Han Sol Kang ◽  
Myun Joong Hwang
Keyword(s):  
High Speed ◽  
Robot Manipulator ◽  
Control Algorithms ◽  
Residual Vibration ◽  
Motion Characteristic ◽  
The Relationship ◽  
Being Moved ◽  
Additional Feedback ◽  
Motion Profile ◽  
Deceleration Time

The residual vibration when a robot manipulator is operated at high speed needs to be suppressed. These vibrations are generated by the resonance of a flexible object being moved by the robot, and research on control algorithms and motion profiles is ongoing to reduce them. In this paper, we propose a method to reduce the residual vibration of an object moved by a robot manipulator by optimizing the acceleration/deceleration time calculated using the object’s natural frequency. The relationship between acceleration/deceleration time and the residual vibration in a trapezoidal velocity profile is considered by analyzing the scenario when the jerking motion characteristic of such vibrations occurs. The results of experiments using a commercial robot show that residual vibrations can be reduced by the proposed method without the need for an additional feedback control algorithm while transferring a flexible object over small and large distances.

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