scholarly journals A novel 5-DOF high-precision compliant parallel mechanism for large-aperture grating tiling

2017 ◽  
Vol 8 (2) ◽  
pp. 349-358 ◽  
Author(s):  
Zhongxi Shao ◽  
Shilei Wu ◽  
Jinguo Wu ◽  
Hongya Fu
Keyword(s):  
High Precision ◽  
Parallel Mechanism ◽  
Closed Loop ◽  
Load Capacity ◽  
Performance Testing ◽  
Closed Loop Control ◽  
Parallel Mechanisms ◽  
Loop Control ◽  
Large Aperture ◽  
Compliant Parallel Mechanism

Abstract. In combination with the advantages of parallel mechanisms and compliant mechanisms, a 5-DOF compliant parallel mechanism is designed to meet the requirements, such as large stroke, large load capacity, high precision and high stability, for a large-aperture grating tiling device. The structure and characteristics of the 5-DOF compliant parallel mechanism are presented. The kinematics of the mechanism are derived based on a pseudo-rigid-body model as well. To increase the tiling position retention stability of the mechanism, a closed-loop control system with capacitive position sensors, which are employed to provide feedback signals, is realized. A position and orientation monitoring algorithm and a single neuron adaptive full closed-loop control algorithm are proposed. Performance testing is implemented to verify the accuracy and the tiling position retention stability of the grating tiling device. The experimental results indicate that the tiling accuracy reaches 0.2 µrad per step and 20 nm per step, and the tiling position retention stability can achieve 1.2 µrad per 30 min and 35 nm per 30 min in the rotational direction and the translational direction, respectively.

High-precision laser ablation using OCT closed-loop control

2020 ◽  
Author(s):  
Daniel Holder ◽  
Matthias Buser ◽  
Artur Leis ◽  
Steffen Boley ◽  
Rudolf Weber ◽  
...  
Keyword(s):  
Laser Ablation ◽  
High Precision ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Loop Control

Automatic Positioning Closed-Loop Control Cystem Design of Linear Time Grating Sensor

2011 ◽  
Vol 328-330 ◽  
pp. 2121-2124
Author(s):  
Tian Heng Zhang ◽  
Dong Lin Peng ◽  
Ji Sen Yang ◽  
Xian Quan Wang ◽  
Chun Dong
Keyword(s):  
Control System ◽  
High Precision ◽  
Closed Loop ◽  
Linear Time ◽  
Stepper Motor ◽  
Feedback Signal ◽  
Closed Loop Control ◽  
Positioning System ◽  
Loop Control ◽  
Automatic Positioning

A high-precise automatic positioning system for data sample of linear time grating sensor is designed. In order to achieve linear time grating sensor of data sample, improve measure work efficiency, an ARM MCU is used as a major chip to control the stepper motor to rotate. In this way, the stepper motor drives the ball screw, the moving probe of linear time grating sensor and reading head of linear grating to move synchronously. A high-precision automatic positioning of the system hardware is designed. In addition, ARM controlling circuits and stepper motor driving circuits are designed. Therefore, the special communication interface is designed for the high-precision automatic positioning system, receiving the feedback signal from time grating sensor, forming a high-precision closed loop control system, and communicating with upper computer by serial. Experiment results prove that the positioning precision of control system can reach 0.1 um.

System Design and Study on Bionic Eye of Spherical Parallel Mechanism Based on Attitude Closed-loop Control

ROBOT ◽  
2011 ◽  
Vol 33 (3) ◽  
pp. 354-359 ◽  
Author(s):  
Chao LI ◽  
Shaorong XIE ◽  
Hengyu LI ◽  
Jinsong MIAO ◽  
Yuanyu XU ◽  
...  
Keyword(s):  
System Design ◽  
Parallel Mechanism ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Loop Control ◽  
Bionic Eye ◽  
Spherical Parallel Mechanism

Study on the nature of stick–slip motion for high-precision table

2011 ◽  
Vol 226 (7) ◽  
pp. 1751-1764 ◽  
Author(s):  
Gao Junwei ◽  
Tao Tao ◽  
Mei Xuesong ◽  
Zhao Fei
Keyword(s):  
High Precision ◽  
Closed Loop ◽  
Numerical Control ◽  
Contour Error ◽  
Friction Compensation ◽  
Closed Loop Control ◽  
Stick Slip ◽  
Loop Control ◽  
Stick Slip Motion ◽  
Slip Motion

Friction is one of the important factors resulting in the contour error of feed servo systems for high-precision computer numerical control machine tools. The beginning criterion of friction compensation is usually based on the recognition that reverse axis velocity reaches zero at quadrant boundary in circular motion. In fact, reverse velocity cannot reach zero at quadrant boundary. This article investigates the dynamics question behind stick–slip motion, based on re-understanding friction and closed-loop control. Here, the stick–slip motions were distinguished as three kinds: positive, negative and full reversals. Moreover, it is also considered that closed-loop control system must produce inhibition to inner disturbance as to friction. The conclusion that friction compensation should take place before the velocity decreases to zero is obtained. The simulation result well illustrates the theoretical analysis of the nature of stick–slip motion. Compensation experiment shows that friction compensation considering negative friction can easily further decrease friction error in high speed.

A New Digital Closed-Loop Control Accelerometer

2013 ◽  
Vol 303-306 ◽  
pp. 124-127
Author(s):  
Bing Tao Lin ◽  
Jian Hua Zhao ◽  
Wen Yun Li ◽  
Qian Zhou ◽  
Xin Man ◽  
...  
Keyword(s):  
High Precision ◽  
Precision Measurement ◽  
Closed Loop ◽  
Large Range ◽  
Measurement Range ◽  
Closed Loop Control ◽  
High Precision Measurement ◽  
Loop Control ◽  
Large Measurement

A digital closed-loop control quartz accelerometer with new structures is performed, which overcomes the disadvantages of restriction of measurement range and sensitivity of QVBA (quartz vibrating beam accelerometer). It has not only the same precision as QVBA in theory, but also large measurement range without reducing the sensitivity. The accelerometer is proposed to be used in large range and high-precision measurement of acceleration.

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