• Title/Summary/Keyword: LuGre 동적마찰모델

Search Result 4, Processing Time 0.015 seconds

Robust Control for Nonlinear Friction Servo System Using Fuzzy Neural Network and Robust Friction State Observer (퍼지신경망과 강인한 마찰 상태 관측기를 이용한 비선형 마찰 서보시스템에 대한 강인 제어)

  • Han, Seong-Ik
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.25 no.12
    • /
    • pp.89-99
    • /
    • 2008
  • In this paper, the position tracking control problem of the servo system with nonlinear dynamic friction is issued. The nonlinear dynamic friction contains a directly immeasurable friction state variable and the uncertainty caused by incomplete parameter modeling and its variations. In order to provide the efficient solution to these control problems, we propose the composite control scheme, which consists of the robust friction state observer, the FNN approximator and the approximation error estimator with sliding mode control. In first, the sliding mode controller and the robust friction state observer is designed to estimate the unknown internal state of the LuGre friction model. Next, the FNN estimator is adopted to approximate the unknown lumped friction uncertainty. Finally, the adaptive approximation error estimator is designed to compensate the approximation error of the FNN estimator. Some simulations and experiments on the servo system assembled with ball-screw and DC servo motor are presented. Results show the remarkable performance of the proposed control scheme. The robust friction state observer can successfully identify immeasurable friction state and the FNN estimator and adaptive approximation error estimator give the robustness to the proposed control scheme against the uncertainty of the friction parameters.

Design of Adaptive Controller to Compensate Dynamic Friction for a Benchmark Robot (벤치마크 로봇의 동적 마찰 보상을 위한 적응 제어기 설계)

  • Kim, In-Hyuk;Cho, Kyoung-Hoon;Son, Young Ik;Kim, Pil-Jun
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.51 no.1
    • /
    • pp.202-208
    • /
    • 2014
  • Friction force on robot systems is highly nonlinear and especially disturbs precise control of the robots at low speed. This paper deals with the dynamic friction compensation problem of a well-known one-link benchmark robot system. We consider the LuGre model because the model can successfully represent dynamic characteristics and various effects of friction phenomenon. The proposed controller is constructed as two parts. An adaptive controller based on dual observers is used to estimate and compensate the dynamic friction. In order to attenuate the friction estimation error and other disturbances, PI observer is additionally designed. Through the computer simulations with the benchmark system, this paper first examines the effects of nonlinear dynamic friction on the control performance of the benchmark robot system. Next, it is shown that the control performance against the dynamic friction is improved by using the proposed controller.

Robust Adaptive Back-stepping Control Using Dual Friction Observer and RNN with Disturbance Observer for Dynamic Friction Model (외란관측기를 갖는 RNN과 이중마찰관측기를 이용한 동적마찰모델에 대한 강인한 적응 백-스테핑제어)

  • Han, Seong-Ik
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.18 no.1
    • /
    • pp.50-58
    • /
    • 2009
  • For precise tracking control of a servo system with nonlinear friction, a robust friction compensation scheme is presented in this paper. The nonlinear friction is difficult to identify the friction parameters exactly through experiments. Friction parameters can be also varied according to contact conditions such as the variation of temperature and lubrication. Thus, in order to overcome these problems and obtain the desired position tracking performance, a robust adaptive back-stepping control scheme with a dual friction observer is developed. In addition, to estimate lumped friction uncertainty due to modeling errors, a DEKF recurrent neural network and adaptive reconstructed error estimator are also developed. The feasibility of the proposed control scheme is verified through the experiment fur a ball-screw system.

Dynamic Behavior Analysis of Tiny Robot

  • Wang, Zhao;Lim, Eng Gee
    • Journal of Convergence Society for SMB
    • /
    • v.4 no.1
    • /
    • pp.17-29
    • /
    • 2014
  • The wireless capsule endoscopy played an important role as the evolutionary medical device to solving the difficulties such as diagnosing the intestine diseases. Due to the limited size and functions, it has some drawbacks. The most obstacle thing is the disability of self-motion, it means that it cannot provide the speed problem. Hence, the characteristics of human digestion system is briefly introduced, especially the intestine, to get the information of endoscopy dynamics. Next, in order to make an abstraction of the condition, a new dynamic friction model called LuGre model is introduced and clearly analysed to get the characteristics and the usage of the model. By the consideration of parameters that are tightly related with the real situation of the capsule endoscopy. The Matlab Simulink was applied to build the model and verified by the simulation to discover the features.

  • PDF