A Simple Force Ripple Compensation Method for Linear Motor Servo System

2006 ◽  
Author(s):  
Jiachun Lin ◽  
Wei Li ◽  
Tong Zhao ◽  
Tianfeng Zhou ◽  
Xiankui Wang ◽  
...  
Keyword(s):  
Servo System ◽  
Linear Motor ◽  
Compensation Method ◽  
Force Ripple

scholarly journals A New Linear Motor Force Ripple Compensation Method Based on Inverse Model Iterative Learning and Robust Disturbance Observer

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19
Author(s):  
Xuewei Fu ◽  
Xiaofeng Yang ◽  
Zhenyu Chen
Keyword(s):  
Iterative Learning Control ◽  
Disturbance Observer ◽  
Learning Control ◽  
Inverse Model ◽  
Iterative Learning ◽  
Compensation Method ◽  
Tracking Accuracy ◽  
Linear Motors ◽  
Learning Speed ◽  
Force Ripple

Permanent magnet linear motors (PMLMs) are gaining increasing interest in ultra-precision and long stroke motion stage, such as reticle and wafer stage of scanner for semiconductor lithography. However, the performances of PMLM are greatly affected by inherent force ripple. A number of compensation methods have been studied to solve its influence to the system precision. However, aiming at some application, the system characteristics limit the design of controller. In this paper, a new compensation strategy based on the inverse model iterative learning control and robust disturbance observer is proposed to suppress the influence of force ripple. The proposed compensation method makes fully use of not only achievable high tracking accuracy of the inverse model iterative learning control but also the higher robustness and better iterative learning speed by using robust disturbance observer. Simulation and experiments verify effectiveness and superiority of the proposed method.

Time-Varying Sliding Mode Control for Linear Motor Servo System

2011 ◽  
Vol 383-390 ◽  
pp. 1267-1272
Author(s):  
Yi Biao Sun ◽  
Lan Yang ◽  
Cheng Yuan Wang
Keyword(s):  
Sliding Mode ◽  
Control Process ◽  
Servo System ◽  
Absolute Error ◽  
Linear Motor ◽  
Time Varying ◽  
Initial State ◽  
Speed Controller ◽  
Parameter Variations ◽  
Global Robustness

For the characteristics of permanent magnet linear motor (PMLSM) servo system in machine tool feeding system suffering from the effect of parameter variations, load disturbances and so on, the time-varying sliding mode position and speed controller was designed. By designing the time-varying sliding mode line, the line is changing with time t and its slope does not change during the control process. And the error state of the control system always lies on the sliding mode line from the beginning of any initial state. The reaching phase is eliminated. During the design process, because of the control signal is restricted, optimize the controller parameters by minimizing the integral absolute error (IAE). And the convergence rate of error is speeded up. The simulation results prove that the system have global robustness to the parameter variations and disturbance.

Ultra-Precision Linear Motor Positioning Technique

1991 ◽  
Vol 3 (4) ◽  
pp. 328-333 ◽  
Author(s):  
Masanori Suematsu ◽  
◽  
Takao Fujii ◽  
Atsushi Kawahara ◽  
Tomoaki Tanimoto ◽  
...  
Keyword(s):  
Temperature Rise ◽  
Normal Force ◽  
Servo System ◽  
Linear Motor ◽  
Pulse Velocity ◽  
Air Bearing ◽  
Positioning Accuracy ◽  
Support Mechanism ◽  
Ultra Precision ◽  
Positioning Technique

This paper introduces an ultra-precision linear motor positioning technique. In order to realize a compact positioning movement without dual structure consisting coarse and fine positionings, higher accuracy air slider studies are conducted on a completely frictionless support mechanism using a linear motor and an externally pressurized air bearing. Results are as follows: (1) Temperature rise of 03°C, table displacement of 0.16μm and guide warp of 0.03μm are achieved by slider guide with adiabatic structure. (2) To reduce cogging force and normal force, coreless and slotless motor is developed. Thrust ripple has reduced to less than 2 % of the rated thrust. (3) Maximum pulse velocity of 10 Mpps, acceleration of 3M/S2, 0.2 sec for 15mm stroke are achieved. (4) Software servo system using DSP is adopted, positioning accuracy of 10nm are achieved without fine positioning.

Permanent Magnet Linear Synchronous Motor Servo System Based on DSP

2011 ◽  
Vol 103 ◽  
pp. 388-393
Author(s):  
Dong Qing Hao ◽  
Lian Qing Zhu ◽  
Zhi Kang Pan ◽  
Yang Kuan Guo ◽  
Qing Shan Chen
Keyword(s):  
Control System ◽  
Servo System ◽  
Linear Motor ◽  
Servo Control ◽  
Feedback Signal ◽  
Power Module ◽  
Current Feedback ◽  
Loop Control ◽  
Servo Control System ◽  
Communication Module

Linear motor has a lot of merits, such as simple structure, fast dynamic response, high localization accuracy and great speed capability. It improves the dynamic sensitivity, accuracy and reliability of modern machining. On the basis of analyzing structure trait and operational principle of linear motor, a position servo control system of linear motor based on DSP is designed. This system is constructed according to vector control model. It consists of a control module, a detection module, a power driver module and a communication module. Closed-loop control strategies based on position feedback, speed feedback and current feedback are adopted. The Space Vector Pulse Width Modulation (SVPWM) integrates an inverter and a motor into a whole, which can make the full digital real-time controlling of PMLSM. TMS320LF2812 is selected as the controller in this control system, which can process the feedback signal of the detection module and output motor-droved current signals. The position and speed detection of linear motor is realized by a QEP circuit with a grating bar. Application of intelligent power module (IPM) simplifies the rectifier circuit and protects the circuit. The communication module is used to make connection between the servo system and a PC. The experimental results show that the servo control system proposed in this paper has reliable structure, good control performance, and simplicity in operation.

Force Control of Linear Motor Stages for Microassembly

2003 ◽  
Author(s):  
Jason J. Gorman ◽  
Nicholas G. Dagalakis
Keyword(s):  
Force Control ◽  
Microelectromechanical Systems ◽  
Linear Motor ◽  
Dynamic Friction ◽  
Nonlinear Friction ◽  
Ripple Effects ◽  
Micro Scale ◽  
Working Volume ◽  
Nonlinear Force ◽  
Force Ripple

The microassembly of microelectromechanical systems from various micro-components requires the development of many new robotic capabilities. One of these capabilities is force control for handling micro-scale components with force control resolution on the order of micronewtons. In this paper, the force control of linear motor stages is discussed with application to the microassembly of MEMS. Linear motor stages provide an attractive solution for microassembly robots because they have a large working volume and can achieve high-precision positioning. However, the nonlinear friction and force ripple effects inherent in linear stages provide an obstacle to the required level of force control. A model of a single motor stage has been developed including dynamic friction effects. Based on this model, a robust nonlinear force controller has been designed to meet the microassembly requirements. The controller has been tested in simulation to demonstrate its effectiveness.

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