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.

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 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

Vibration Control of Moving Flexible Structure by Repetitive Control

1995 ◽  
Author(s):  
Shinji Mitsuta ◽  
Hideki Tsuji ◽  
Hiroyuki Itoh ◽  
Yasushi Ogasawara ◽  
Kazuto Seto
Keyword(s):  
Feedback Control ◽  
Control Method ◽  
Repetitive Control ◽  
Model Identification ◽  
Step Response ◽  
Flexible Structure ◽  
Hydraulic Actuator ◽  
Residual Vibration ◽  
Vibration Displacement ◽  
Simulation And Experiment

Abstract The purpose of this study is to move a flexible structure, such as conveyance equipment that moves periodically, quickly and accurately by controlling its vibration. In order to reduce the vibration of a flexible structure actively, a hydraulic actuator is arranged on the motion transmission path between a drive system and a flexible structure. Generally, it is possible to obtain good effects for reducing a residual vibration by using feedback control. However, the vibration displacement in motion is mainly forced vibration which is caused by motion acceleration, so it is difficult to reduce the vibration displacement by using feedback control. Thus, by considering that the flexible structure is driven periodically, we use the repetitive control method to reduce the vibration displacement in motion. In this study, the repetitive control method with the step response, which does not need model identification, is shown. Furthermore, the validity of this method is examined by simulation and experiment.

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.

scholarly journals Study on Acc/Dec Algorithm Based on Piecewise Polynomial in CNC

2011 ◽  
Vol 2-3 ◽  
pp. 43-47 ◽  
Author(s):  
Guo Shun Ji ◽  
Zhi Ping Chen ◽  
Ju Yong Zhang ◽  
Wei Liu
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Polynomial Function ◽  
Tracking Accuracy ◽  
Feedrate Planning ◽  
Smooth Motion ◽  
Planning Algorithm ◽  
S Curve ◽  
The Stability ◽  
Motion Profile

In order to improve the stability of feed movement in high speed CNC system, the feedrate planning algorithm based on piece-wise polynomial function was proposed. The flexible transition of feedrate was realized through maintaining linear continuous jerk. The principle of the proposed algorithm was introduced and the method to generate smooth motion profile based on the proposed algorithm was presented. The rapidity, stability and tracking accuracy of the feedrate planning algorithm to linearity, S curve and the proposed one were analyzed. The proposed algorithm is simple and it can be applied in acceleration/deceleration before interpolation in high speed feed movement to improve the stability of it. The proposed algorithm was applied in multi-contour high speed processing and the result indicated that it could improve the stability of large-scale parts motion.

GAP CONTROL OF ELECTRICAL DISCHARGE GRINDING WITH HIGH BANDWIDTH DUAL STAGE ACTUATORS

2015 ◽  
Vol 75 (11) ◽  
Author(s):  
Bo Hu ◽  
M. Zulafif Rahim ◽  
Songlin Ding ◽  
Milan Brandt ◽  
Christopher Lim ◽  
...  
Keyword(s):  
Piezoelectric Actuator ◽  
Electrical Discharge ◽  
Electrical Discharge Machine ◽  
Travel Distance ◽  
Feedback Signal ◽  
Linear Actuator ◽  
High Bandwidth ◽  
Dual Stage ◽  
Stage System ◽  
Gap Width

Electrical discharge grinding process has four types of discharge states and abnormal states, such as arcs and short circuits have great impact on the machining efficiency and the surface finish of workpieces, for example, polycrystalline diamond cutting tools. The aim of this study had been to develop a new servo system with high bandwidth dual stage actuators, which can quickly change the gap width to eliminate these harmful discharge states. The structure of the dual stage system is that a piezoelectric actuator stands on a linear actuator and both move along one axis. The piezoelectric actuator, which has high bandwidth but short travel distance, was used for the gap width control and the linear actuator, which is relatively slow but has long travel distance, tunes the feed rate of the workpiece to match the erosion rate. The gap information obtained from the electrical discharge waveform was used as a feedback signal. The linear actuator system adjusted its velocity based on the average piezoelectric displacement value. Hence, an electrical discharge machine was developed with a one-axis dual stage system. The results from simulations and experiments showed that the new system provided a high bandwidth response, as well as enhanced the machining rate and stability.  

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