Contouring Performance Improvement of Biaxial Motion Control Systems Using Friction and Disturbance Compensation

2012 ◽  
Vol 579 ◽  
pp. 287-296 ◽  
Author(s):  
Ke Han Su ◽  
Ming Yang Cheng ◽  
Yu Chen Chang
Keyword(s):  
Motion Control ◽  
Friction Force ◽  
External Disturbance ◽  
Friction Model ◽  
Free Form ◽  
Contour Error ◽  
Linear Motors ◽  
Virtual Plant ◽  
Contouring Accuracy ◽  
Contour Following

One of the key issues regarding multi-axis contour following tasks in modern high-precision machining applications is how to effectively reduce contour error. Generally, among existing approaches, the Cross-Coupled Control (CCC) structure is widely used in multi-axis contour following tasks to improve contouring accuracy. However, when a servomechanism is operated in reverse or low-speed motions, the inherent friction force and external disturbance effects will degrade the CCC performance. Therefore, to cope with the aforementioned problems, this paper exploits the Karnopp friction model-based compensator and the Virtual Plant Disturbance Compensator (VPDC) to improve tracking performance as well as contouring accuracy. Moreover, an integrated motion control scheme is also developed to further improve contouring performance. The proposed scheme consists of two position loop controllers with velocity command feedforward, a modified CCC, two friction force compensators, and two disturbance compensators. To evaluate the performance of the proposed approach, several free-form contour following experiments have been conducted on an X-Y table driven by two linear motors. Experimental results verify that the proposed approach can significantly enhance contouring performance for free-form contour following tasks.

Iterative Learning Cross-Coupled Control for XY Table Based on Real-Time Contour Error Estimation

2011 ◽  
Vol 383-390 ◽  
pp. 7054-7059 ◽  
Author(s):  
Li Mei Wang ◽  
Qi Yang ◽  
Yi Biao Sun ◽  
Chun Fang Liu
Keyword(s):  
Real Time ◽  
External Disturbance ◽  
Iterative Learning ◽  
Free Form ◽  
Contour Error ◽  
Dynamic Matching ◽  
Linear Motors ◽  
Control Scheme ◽  
Table Model ◽  
Estimate Method

The contour accuracy of XY table directly driven by two linear motors was influenced by the complicated reel-time contour error model of free-form curves, uncertainty external disturbance and dynamic matching between X axis and Y axis. To establish XY table model that easily calculated and suitable for free-form curves, real-time contour error estimate method was adopted. In order to reduce uncertainty external disturbance and dynamic matching between X axis and Y axis, the iterative learning cross-coupled controller (ILCCC) was designed for current compensation on X axis and Y axis. Simulation results show that the control scheme can enhance the robustness of the system, and effectively improve the XY table of contour precision.

Cross-Coupled Adaptive Feedrate Control for Multiaxis Machine Tools

1991 ◽  
Vol 113 (3) ◽  
pp. 451-457 ◽  
Author(s):  
Hua-Yi Chuang ◽  
Chang-Huan Liu
Keyword(s):  
Computer Simulation ◽  
Control System ◽  
Motion Control ◽  
Control Strategy ◽  
Machine Tools ◽  
Feedback Loop ◽  
Contour Error ◽  
Coupled Motion ◽  
Contouring Accuracy ◽  
Perturbed Model

Cross-coupled controllers have been proposed for improving contouring accuracy of multiaxis machine tools. However, during cross-coupled motion control, increasing contour feedrate may result in larger contour errors. In order to increase feedrate and hence productivity without sacrificing the contouring performance, this paper presents an adapative feedrate control strategy based on a linear perturbed model. The method effectively closes the feedback loop between the contour error and feedrate. An experimental biaxial control system is constructed to implement the proposed strategy. Both computer simulation and experiments have verified that desired contouring accuracy can be achieved.

Synchronized Control of Dual Linear Motors Position Servo System Based on Multi-Axes Motion Control Card

2012 ◽  
Vol 433-440 ◽  
pp. 7152-7158 ◽  
Author(s):  
Cheng Ying ◽  
Hai Chen Qin ◽  
Jian Zhou Quan
Keyword(s):  
Motion Control ◽  
Feedforward Control ◽  
External Disturbance ◽  
Servo System ◽  
Linear Motors ◽  
Control Scheme ◽  
Motion Control Card ◽  
Synchronous Error ◽  
Control Feedback ◽  
Synchronized Control

This paper introduces a position synchronized control strategy to deal with the synchronous error caused by the external disturbance in dual linear motors servo system. In order to achieve satisfactory results, a new control scheme combing feedforward control, feedback control and cross-coupled control is proposed and makes progress in decreasing the synchronous error which was shown by the experiment.

Precision Motion Control Methodology for Complex Contours

2007 ◽  
Vol 129 (6) ◽  
pp. 1060-1068 ◽  
Author(s):  
Haojiong Zhang ◽  
Robert G. Landers
Keyword(s):  
Motion Control ◽  
Friction Model ◽  
Free Form ◽  
Unmodeled Dynamics ◽  
Nonlinear Friction ◽  
General Reference ◽  
Precision Motion Control ◽  
Unknown Disturbances ◽  
Precision Motion ◽  
Control Methodology

A general precision motion control methodology for complex contours is proposed in this paper. Each motion servomechanism dynamic model is divided into a linear portion and a portion containing nonlinear friction, unmodeled dynamics, and unknown disturbances. A full state feedback controller, based on a state space error system model, is developed to track general reference trajectories. The lumped static, Coulomb, and Stribeck friction effects are described using the Tustin friction model. Unmodeled dynamics and unknown disturbances are estimated using a Kalman filter that employs a first-order stochastic model. The nonlinear friction, unmodeled dynamics, and unknown disturbances are directly canceled by the controller. In the proposed motion control methodology, complex contours (i.e., contours whose radii of curvature constantly change along the contour) do not need to be decomposed into line segments and arcs and the reference signals do not need to be prefiltered. Also, the controller structure does not need to be adjusted to track different types of contours. Experiments are conducted on a two-axis laboratory grade machine tool for elliptical, limacon, and free-form contours. The results demonstrate the excellent tracking performance of the proposed motion control methodology. They also demonstrate that the performance is independent of the contours’ complexity.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

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