Using asymmetric S-curve profile for fast and vibrationless motion

2007 ◽  
Author(s):  
Keun-Ho Rew ◽  
Kyung-Soo Kim
Keyword(s):  
Curve Profile ◽  
S Curve

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

scholarly journals Embedded Input Shaper: Difference between Trapezoidal Profile and S-curve Profile

2014 ◽  
Vol 20 (11) ◽  
pp. 1125-1130
Author(s):  
Chang-Wan Ha ◽  
Dongwook Lee ◽  
Byungho Yoon ◽  
Keun-Ho Rew ◽  
Kyung-Soo Kim
Keyword(s):  
Input Shaper ◽  
Curve Profile ◽  
Trapezoidal Profile ◽  
S Curve

Time-Optimal Freeform S-Curve Profile Under Positioning Error and Robustness Constraints

2018 ◽  
Vol 23 (4) ◽  
pp. 1993-2003 ◽  
Author(s):  
Youdun Bai ◽  
Xin Chen ◽  
Han Sun ◽  
Zhijun Yang
Keyword(s):  
Positioning Error ◽  
Time Optimal ◽  
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.

Methodology for determining water losses from irrigation canals

2020 ◽  
pp. 16-18
Author(s):  
Elena Makarycheva
Keyword(s):  
Filtration Rate ◽  
Darcy Law ◽  
Filtration Flow ◽  
Irrigation Canals ◽  
Power Functions ◽  
Two Phase ◽  
Water Losses ◽  
Irrigation Channels ◽  
Unsteady Filtration ◽  
S Curve

The aim of the article is to develop a method for calculating water losses from irrigation channels in determining the permeability of rock in the zone of filtration flow on the basis of the law of infiltration A.N. Kostyakov using the results of studies of free filtration from pits and foundation pits in loess loams. Pressure movement of water in irrigation canals is subject to the laws of two-phase flow, in which – in contrast to the Darcy law for the zone of saturation plays an important role, the volume and its change in time. The filtration rate (VF) increases with increasing rock moisture (θ) along the S-curve, while the pressure gradient (I = dh/dz) decreases. The dependences of these parameters on the pressure are represented by power functions, and their product CDP = VFI does not change in time and can serve as a characteristic of the filtration flow under the channel. When installing paired piezometers near the water chore line in the channel and determining the graph I(t) by the value of the twophase flow constant CDP, it is possible to calculate the filtration rate at a number of times and the water losses during unsteady filtration. Water losses from the channels at equilibrium humidity increases with increasing head according to the formula A.N. Kostyakova, in which the water permeability of rocks is characterized by a steady filtration rate at a head of 1.0 m, and the gradient is the function of pressure. The application of the proposed method of calculating losses in the design of irrigation systems will increase the reliability of the justification of the volume of anti-filtration measures and the forecast of the groundwater level.

Two Candidate Approaches o Text Sequencing: An Addendum to “The Diachrony Debate: A Tutorial on Methods”

2018 ◽  
Vol 26 (2) ◽  
Author(s):  
Dean A. Forbes
Keyword(s):  
Computational Biology ◽  
Middle English ◽  
Diagnostic Tool ◽  
Reliable Method ◽  
Biblical Hebrew ◽  
Quantitative Comparison ◽  
Curve Analysis ◽  
Single Feature ◽  
S Curve ◽  
Temporal Ordering

In a recent essay published in this journal, I illustrated the limitations one may encounter when sequencing texts temporally using s-curve analysis. I also introduced seriation, a more reliable method for temporal ordering much used in both archaeology and computational biology. Lacking independently ordered Biblical Hebrew (BH) data to assess the potential power of seriation in the context of diachronic studies, I used classic Middle English data originally compiled by Ellegård. In this addendum, I reintroduce and extend s-curve analysis, applying it to one rather noisy feature of Middle English. My results support Holmstedt’s assertion that s-curve analysis can be a useful diagnostic tool in diachronic studies. Upon quantitative comparison, however, the five-feature seriation results derived in my former paper are found to be seven times more accurate than the single-feature s-curve results presented here. 

Curve Estimation Modeling for Predictions of the Novel Coronavirus (Covid-19) Epidemic in Nigeria

2020 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Christian Ebere Enyoh ◽  
Andrew Wirnkor Verla ◽  
Chidi Edbert Duru ◽  
Emmanuel Chinedu Enyoh ◽  
Budi Setiawan
Keyword(s):  
State Governments ◽  
The Novel ◽  
Curve Estimation ◽  
Exponential Models ◽  
Inverse Models ◽  
Forward Prediction ◽  
S Curve ◽  
Novel Coronavirus ◽  
Best Fit ◽  
Official Data

Based on the official Nigeria Centre for Disease Control (NCDC) data, the current research paper modeled the confirmed cases of the novel coronavirus disease 2019 (COVID-19) in Nigeria. Ten different curve regression models including linear, logarithmic, inverse, quadratic, cubic, compound, power, S-curve, growth, and exponential were used to fit the obtained official data. The cubic (R2 = 0.999) model gave the best fit for the entire country. However, the growth and exponential had the lowest standard error of estimate (0.958) and thus may best be used. The equations for these models were e0.78897+0.0944x and 2.2011e0.0944x respectively. In terms of confirmed cases in individual State, quadratic, cubic, compound, growth, power and exponential models generally best describe the official data for many states except for the state of Kogi which is best fitted with S-curve and inverse models.  The error between the model and the official data curve is quite small especially for compound, power, growth and exponential models. The computed models will help to realized forward prediction and backward inference of the epidemic situation in Nigeria, and the relevant analysis help Federal and State governments to make vital decisions on how to manage the lockdown in the country.

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