Accurate Motion Control of Linear Motors With Adaptive Robust Compensation of Nonlinear Electromagnetic Field Effect

2011 ◽  
Author(s):  
Zheng Chen ◽  
Bin Yao ◽  
Qingfeng Wang
Keyword(s):  
Electromagnetic Field ◽  
Steady State ◽  
Motion Control ◽  
Field Effect ◽  
Linear Motor ◽  
Adaptive Robust Control ◽  
Tracking Performance ◽  
Positioning Systems ◽  
Linear Motors ◽  
Driving Current

Iron-core linear motors have been widely used in high-speed/high-accuracy positioning systems due to the elimination of mechanical transmissions. Many control methodologies have been developed for linear motor motion control, such as H∞ control, adaptive control and sliding mode control. Compensations of various nonlinearities such as frictions and cogging forces have also been carried out to obtain better tracking performance. However, the relationship between the driving current and the resulting motor force has been assumed to be linear, which is invalid for high driving coil currents due to the saturating electromagnetic field effect. This paper focuses on the effective compensation of nonlinear electromagnetic field effect so that the system can be operated at even higher acceleration or heavier load without losing achievable control performance. Specifically, cubic polynomials with unknown weights are used for an effective approximation of the unknown nonlinearity between the electromagnetic force and the driving current. The effectiveness of such an approximation is verified by off-line identification experiments. An adaptive robust control (ARC) algorithm with online tuning of the unknown weights and other system parameters is then developed to account for various uncertainties. Theoretically, the proposed ARC algorithm achieves a guaranteed transient and steady-state performance for position tracking, as well as zero steady-state tracking error when subjected to parametric uncertainties only. Comparative experiments of ARC with and without compensation of electromagnetic nonlinearity done on a linear-motor-driven industrial gantry will be shown. The results show that the proposed ARC algorithm achieves better tracking performance than existing ones, validating the effectiveness of the proposed approach in practical applications.

Indirect Neural Network Adaptive Robust Control of Linear Motor Drive System

2002 ◽  
Author(s):  
J. Q. Gong ◽  
Bin Yao
Keyword(s):  
Neural Network ◽  
Robust Control ◽  
Tracking Error ◽  
Linear Motor ◽  
Adaptive Robust Control ◽  
Operating Conditions ◽  
Tracking Performance ◽  
Motor Drive ◽  
Output Tracking ◽  
On Line

In this paper, an indirect neural network adaptive robust control (INNARC) scheme is developed for the precision motion control of linear motor drive systems. The proposed INNARC achieves not only good output tracking performance but also excellent identifications of unknown nonlinear forces in system for secondary purposes such as prognostics and machine health monitoring. Such dual objectives are accomplished through the complete separation of unknown nonlinearity estimation via neural networks and the design of baseline adaptive robust control (ARC) law for output tracking performance. Specifically, recurrent neural network (NN) structure with NN weights tuned on-line is employed to approximate various unknown nonlinear forces of the system having unknown forms to adapt to various operating conditions. The design is actual system dynamics based, which makes the resulting on-line weight tuning law much more robust and accurate than those in the tracking error dynamics based direct NNARC designs in implementation. With a controlled learning process achieved through projection type weights adaptation laws, certain robust control terms are constructed to attenuate the effect of possibly large transient modelling error for a theoretically guaranteed robust output tracking performance in general. Experimental results are obtained to verify the effectiveness of the proposed INNARC strategy. For example, for a typical point-to-point movement, with a measurement resolution level of ±1μm, the output tracking error during the entire execution period is within ±5μm and mainly stays within ±2μm showing excellent output tracking performance. At the same time, the outputs of NNs approximate the unknown forces very well allowing the estimates to be used for secondary purposes such as prognostics.

DD-type Linear Motor Systems and Their Applications

1989 ◽  
Vol 1 (4) ◽  
pp. 328-332
Author(s):  
Tamotsu Suzuki ◽  
Keyword(s):  
Motor Development ◽  
Linear Motor ◽  
Drive System ◽  
Industrial Robots ◽  
Added Value ◽  
Direct Drive ◽  
Positioning Systems ◽  
Factory Automation ◽  
Linear Motors ◽  
Linear Drive System

Carrying and positioning systems for linear movement in factory automation are typically a combination of a motor and motion-translating mechanisms, such as ball screws, belts, and racks and pinions. Such mechanical motion-translating mechanisms, however, have the disadvantages of limited accuracy, speed, and durability. As a solution to this problem, direct-drive linear motors, which drive an object directly mounted on the drive section, have attracted considerable interest, and various types of linear motors have been actually used. The recent trend in linear motor development has been such that the functions of the motor alone have been expanded into higher functions of the linear drive system. The ""Megathrust Motor"" is a direct drive linear actuator system developed by Nippon Seiko K.K. It has some components, such as a detector and drive unit, which are different from those of other drive systems, and therefore provide high performance and added value. Nippon Seiko K.K. has also developed and marketed a direct drive ""Megatorque Motor."" This motor has achieved high speed and highly accurate rotational drive of industrial robots and general industrial machines, and has been widely used as a rotary actuator in factory automation. The Megathrust Motor is a linear drive system developed as an application of the technology of the Megatorque Motor. This paper describes the features, performance, and applications of the Megathrust Motor.

Adaptive Robust Tip Tracking Control for Single-Link Flexible Beam

2015 ◽  
Author(s):  
Jianfeng Liao ◽  
Cong Li ◽  
Bin Yao ◽  
Xiaocong Zhu
Keyword(s):  
Control Strategy ◽  
Tracking Control ◽  
Linear Motor ◽  
Adaptive Robust Control ◽  
Tracking Performance ◽  
Flexible Beam ◽  
Parameter Uncertainties ◽  
Output Redefinition ◽  
Single Link ◽  
Flexible Beam System

This paper presents an inversion-based adaptive robust tip tracking control strategy that results in high tracking performance while guaranteeing the robustness for a class of linear motor driven single-link flexible beam. To address the non-minimum phase characteristics of the system, the inversion control is achieved by applying output redefinition technique as well as defining the new output at the tip of the flexible beam. In addition, the adaptive robust control (ARC) is introduced to deal with the parameter uncertainties and model uncertainties and to guarantee transient and steady state tracking performance. Comparative simulations and actual experiments based on linear motor driven flexible beam system are carried out to verify the effectiveness of the proposed control strategy.

Adaptive Robust Control of a Linear Motor Driven Precision Industrial Gantry With Improved Cogging Force Compensation

2008 ◽  
Author(s):  
Lu Lu ◽  
Bin Yao ◽  
Zheng Chen ◽  
Qingfeng Wang
Keyword(s):  
Linear Motor ◽  
Adaptive Robust Control ◽  
Force Model ◽  
Practical Applications ◽  
Linear Motors ◽  
Proposed Model ◽  
On Line ◽  
Linear Encoder ◽  
Sinusoidal Functions ◽  
Force Compensation

This paper proposes a new model for cogging forces of linear motor systems. Sinusoidal functions of positions are used to capture the largely periodic nature of cogging forces with respect to position effectively while B-spline functions are employed to account for the additional aperiodic part of cogging forces. This model is experimentally demonstrated to be able to capture both the periodic and non-periodic characteristics of cogging force while having a linear parametrization form which makes effective on-line adaptive compensation of cogging forces possible. A discontinuous projection based desired compensation adaptive robust controller (DCARC) is then constructed for linear motors, which makes full use of the proposed cogging force model for an improved cogging force compensation. Comparative experimental results are obtained on both axes of a linear motor driven Anorad industrial gantry having a linear encoder resolution of 0.5 μm. Experiments are done with each axis running separately to compare the three algorithms: DCARC without cogging force compensation, DCARC with sinusoidal cogging force model compensation, and DCARC with the proposed cogging force model compensation. The results show that DCARC with proposed model compensation achieves the best tracking performance among the three algorithms tested, validating the proposed cogging force model. The excellent tracking performances obtained in experiments also verify the effectiveness of the proposed ARC control algorithms in practical applications.

Generalised Theory of Ferrite-Field D.C. Linear Motors

1979 ◽  
Vol 16 (1) ◽  
pp. 43-49 ◽  
Author(s):  
A. Basak
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Linear Motor ◽  
Motor Speed ◽  
Linear Motors

A theory has been developed for the ferrite field d.c. linear motor based upon the generalised machine approach. Expressions for steady state and transient response of such motors have also been developed. Various motor parameters can be determined by analysing the transient response of the motor speed.

Development of Semicircular Tubular Core-less Linear Motor and Its Motion Control

2015 ◽  
Vol 135 (3) ◽  
pp. 246-257 ◽  
Author(s):  
Mototsugu Omura ◽  
Tomoyuki Shimono ◽  
Yasutaka Fujimoto
Keyword(s):  
Motion Control ◽  
Linear Motor

Analysis of Vibration Caused by Electromagnetic Force on Stator End-Winding of Large Dry Submersible Motor

2013 ◽  
Vol 416-417 ◽  
pp. 428-432
Author(s):  
Li Shan ◽  
Xiao Wei Cheng ◽  
Yong Fang ◽  
Xiao Hua Bao
Keyword(s):  
Electromagnetic Field ◽  
Steady State ◽  
Transition State ◽  
Electromagnetic Force ◽  
Radial Displacement ◽  
Radial Direction ◽  
Axial Direction ◽  
Axial Displacement ◽  
Force Density ◽  
Submersible Motor

This paper investigates the vibration which caused by electromagnetic on the stator end-winding of the large dry submersible motor. Firstly, the electromagnetic field which included transition state and steady state is researched by 3-D FEM. Secondly, the electromagnetic force which lead to vibrations of end-winding is calculated by numerical method, it can be obtained that where endured the largest force density along the slant part of end-winding. Finally, the radial displacement and the axial displacement of the slant part which caused by vibrations is studied, the analysis results show that the axial displacement is larger than the amplitude of radial displacement. It indicates that the slant part of end-winding will be more easily damaged at axial direction than radial direction.

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