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Marian Wiercigroch - One of the best experts on this subject based on the ideXlab platform.

  • Modelling of regenerative and frictional cutting dynamics
    International Journal of Mechanical Sciences, 2019
    Co-Authors: Yao Yan, Marian Wiercigroch
    Abstract:

    Abstract As most investigations of regenerative and frictional cutting chatters have been performed separately up to now, this paper aims to bridge the gap between the two sources of cutting instability by a new simple one degree-of-freedom (DOF) model involving both time-delayed regenerative Effect in chip thickness and Stribeck Effect in frictional velocity. In addition, process damping introduced by the interaction between workpiece material and tool’s flank face is included as well for the discussion of cutting stability in low-velocity zone. By comparing with other results, it is validated that the new model with Stribeck Effect improves the prediction of linear cutting stability in the low-velocity zone. Then the influences of friction on the linear stability is extensively investigated, which shows that a small coefficient of static friction and a large Stribeck velocity benefit the cutting stability in low- and intermediate-velocity zones. In addition, linear analysis of the cutting geometries proves that large shear and rake angles can improve the cutting stability as well.

  • Regenerative and frictional chatter in plunge grinding
    Nonlinear Dynamics, 2016
    Co-Authors: Yao Yan, Marian Wiercigroch
    Abstract:

    This paper studies self-excited vibrations, regenerative and frictional chatters, in a plunge grinding process. In consideration of lateral and torsional workpiece movements, a dynamic model with four degrees of freedom is proposed, which involves state-dependent time delays and Stribeck Effect for regenerative and frictional Effects, respectively. With this model, by linearising contact angle, regenerative grinding depth, frictional velocity and the state-dependent delays, eigenvalue analysis yields stability diagrams for the grinding, where boundaries for both regenerative and frictional instabilities are determined. Then, near the boundaries, simulations and bifurcation analyses are performed to reveal patterns of chatter onset. Bifurcation diagrams show coexistence of stable grinding and the regenerative chatter near the regenerative boundary, and a sudden switch between the stable and the frictionally unstable on the frictional boundary. Moreover, simulation results also show various dynamical properties in the grinding chatters, such as Effect of losing contact and stick–slip motion.

  • Forward and backward motion control of a vibro-impact capsule system.
    International Journal of Non-Linear Mechanics, 2015
    Co-Authors: Yang Liu, Marian Wiercigroch, Ekaterina Pavlovskaia, Zhike Peng
    Abstract:

    A capsule system driven by a harmonic force applied to its inner mass is considered in this study. Four various friction models are employed to describe motion of the capsule in different environments taking into account Coulomb friction, viscous damping, Stribeck Effect, pre-sliding, and frictional memory. The non-linear dynamics analysis has been conducted to identify the optimal amplitude and frequency of the applied force in order to achieve the motion in the required direction and to maximize its speed. In addition, a position feedback control method suitable for dealing with chaos control and coexisting attractors is applied for enhancing the desirable forward and backward capsule motion. The evolution of basins of attraction under control gain variation is presented and it is shown that the basin of the desired attractors could be significantly enlarged by slight adjustment of the control gain improving the probability of reaching such an attractor.

  • Vibro-impact responses of capsule system with various friction models
    International Journal of Mechanical Sciences, 2013
    Co-Authors: Yang Liu, Ekaterina Pavlovskaia, David F. Hendry, Marian Wiercigroch
    Abstract:

    Abstract The dynamics of the vibro-impact system which consists of a capsule main body interacting with a harmonically driven internal mass in various environments is studied in this paper. The environmental resistance is described by four different friction models which take into account Coulomb friction, viscous damping, Stribeck Effect, pre-sliding, and frictional memory. Our investigations are mainly focussed on the qualitative changes in the capsule dynamics. The bifurcation analysis is conducted by monitoring the mass velocity and the average progression of the capsule per period of excitation under variation of the mass ratio. By observing the progression of the capsule, we find that directional control of the system can be achieved either by varying its mass ratio or by switching between co-existing attractors.

Nathan Van De Wouw - One of the best experts on this subject based on the ideXlab platform.

  • Set-point control of motion systems with uncertain set-valued Stribeck friction
    IFAC-PapersOnLine, 2017
    Co-Authors: Ruud Beerens, H Henk Nijmeijer, Maurice Heemels, Nathan Van De Wouw
    Abstract:

    Abstract In this paper, we present a control architecture for the set-point stabilization of motion systems subject to set-valued friction, including a velocity-weakening (Stribeck) Effect. The proposed controller consists of a switching PID term and a term that robustly compensates for the Stribeck Effect. It is shown that the controller asymptotically stabilizes the set-point, and a particular design of the integrator part of the PID controller term allows for faster convergence when overshoot occurs, compared to a conventional integrator. Moreover, this controller is shown to be robust for unknown static friction, and an uncertain contribution of the Stribeck Effect. The working principle of the controller is illustrated by means of a numerical example.

  • Brief paper: Analysis of undercompensation and overcompensation of friction in 1DOF mechanical systems
    Automatica, 2007
    Co-Authors: Devi Putra, H Henk Nijmeijer, Nathan Van De Wouw
    Abstract:

    This paper investigates the Effects of undercompensation and overcompensation of friction in PD controlled 1DOF mechanical systems. The friction force that is acting on the mechanical system and the friction compensation term in the feedback loop are described by a class of discontinuous friction models consisting of static, Coulomb and viscous friction, and including the Stribeck Effect. Lyapunov's stability theorem and LaSalle's invariance principle are applied to prove that undercompensation of friction leads to steady-state errors and the properties of the @w-limit set of trajectories of a two-dimensional autonomous differential inclusion are used to show that overcompensation of friction may induce limit cycling. Furthermore, the analysis also indicates that the limit cycling Effect can be eliminated by tuning the PD controller gains.

Yang Liu - One of the best experts on this subject based on the ideXlab platform.

  • Forward and backward motion control of a vibro-impact capsule system.
    International Journal of Non-Linear Mechanics, 2015
    Co-Authors: Yang Liu, Marian Wiercigroch, Ekaterina Pavlovskaia, Zhike Peng
    Abstract:

    A capsule system driven by a harmonic force applied to its inner mass is considered in this study. Four various friction models are employed to describe motion of the capsule in different environments taking into account Coulomb friction, viscous damping, Stribeck Effect, pre-sliding, and frictional memory. The non-linear dynamics analysis has been conducted to identify the optimal amplitude and frequency of the applied force in order to achieve the motion in the required direction and to maximize its speed. In addition, a position feedback control method suitable for dealing with chaos control and coexisting attractors is applied for enhancing the desirable forward and backward capsule motion. The evolution of basins of attraction under control gain variation is presented and it is shown that the basin of the desired attractors could be significantly enlarged by slight adjustment of the control gain improving the probability of reaching such an attractor.

  • Vibro-impact responses of capsule system with various friction models
    International Journal of Mechanical Sciences, 2013
    Co-Authors: Yang Liu, Ekaterina Pavlovskaia, David F. Hendry, Marian Wiercigroch
    Abstract:

    Abstract The dynamics of the vibro-impact system which consists of a capsule main body interacting with a harmonically driven internal mass in various environments is studied in this paper. The environmental resistance is described by four different friction models which take into account Coulomb friction, viscous damping, Stribeck Effect, pre-sliding, and frictional memory. Our investigations are mainly focussed on the qualitative changes in the capsule dynamics. The bifurcation analysis is conducted by monitoring the mass velocity and the average progression of the capsule per period of excitation under variation of the mass ratio. By observing the progression of the capsule, we find that directional control of the system can be achieved either by varying its mass ratio or by switching between co-existing attractors.

Oleg Makarenkov - One of the best experts on this subject based on the ideXlab platform.

H Henk Nijmeijer - One of the best experts on this subject based on the ideXlab platform.

  • Set-point control of motion systems with uncertain set-valued Stribeck friction
    IFAC-PapersOnLine, 2017
    Co-Authors: Ruud Beerens, H Henk Nijmeijer, Maurice Heemels, Nathan Van De Wouw
    Abstract:

    Abstract In this paper, we present a control architecture for the set-point stabilization of motion systems subject to set-valued friction, including a velocity-weakening (Stribeck) Effect. The proposed controller consists of a switching PID term and a term that robustly compensates for the Stribeck Effect. It is shown that the controller asymptotically stabilizes the set-point, and a particular design of the integrator part of the PID controller term allows for faster convergence when overshoot occurs, compared to a conventional integrator. Moreover, this controller is shown to be robust for unknown static friction, and an uncertain contribution of the Stribeck Effect. The working principle of the controller is illustrated by means of a numerical example.

  • Brief paper: Analysis of undercompensation and overcompensation of friction in 1DOF mechanical systems
    Automatica, 2007
    Co-Authors: Devi Putra, H Henk Nijmeijer, Nathan Van De Wouw
    Abstract:

    This paper investigates the Effects of undercompensation and overcompensation of friction in PD controlled 1DOF mechanical systems. The friction force that is acting on the mechanical system and the friction compensation term in the feedback loop are described by a class of discontinuous friction models consisting of static, Coulomb and viscous friction, and including the Stribeck Effect. Lyapunov's stability theorem and LaSalle's invariance principle are applied to prove that undercompensation of friction leads to steady-state errors and the properties of the @w-limit set of trajectories of a two-dimensional autonomous differential inclusion are used to show that overcompensation of friction may induce limit cycling. Furthermore, the analysis also indicates that the limit cycling Effect can be eliminated by tuning the PD controller gains.

  • Observer design for an experimental rotor system with discontinuous friction
    2006 American Control Conference, 2006
    Co-Authors: A.l. Juloski, Nenad Mihajlovic, Wpmh Maurice Heemels, N. Van De Wouw, H Henk Nijmeijer
    Abstract:

    In this paper we present an experimental observer design for a rotor system with friction. The model of the system exhibits set-valued static friction law with the Stribeck Effect. As the model of the setup is non-smooth and non-Lipschitz, observer has to be designed using mathematical tools from convex analysis and the theory of differential inclusions. The designed observer guarantees that there exists a unique solution to the observer dynamics and that the estimated state converges to the true state of the system. Simulation and experimental results illustrate the design and performance of the observer in practice.

  • Analysis of Friction Compensation Effects in Controlled Mechanical Systems
    2006
    Co-Authors: D. Putra, H Henk Nijmeijer, Van De N Nathan Wouw, Ocl Haas, Keith J. Burnham
    Abstract:

    In this paper, the Effects of friction compensation, including exact compensation, undercompensation and overcompensation, in PD controlled 1DOF mechanical systems are investigated. The friction force that is acting on the mechanical system and the friction compensation termin the feedback loop are described by a class of discontinuous friction models consistingof static, Coulomb and viscous friction, and including the Stribeck Effect. In order to capture the sticking phenomenon at zero velocity, the friction model is expressed as a multi-valued map. Lyapunov’s stability theorem, LaSalle’s invariance principle and the properties of the omega-limit set of trajectories of a2-dimensional differential inclusion are employed to show that firstly, exact compensation leads to global exponential stability of the setpoint, secondly, undercompensation leads to steady state errors, and thirdly, overcompensation conditionally induceslimit cycling.

  • Friction-Induced Limit Cycling in Flexible Rotor Systems: An Experimental Drill-String System
    Volume 1: 20th Biennial Conference on Mechanical Vibration and Noise Parts A B and C, 2005
    Co-Authors: N. Van De Wouw, H Henk Nijmeijer, Nenad Mihajlovic
    Abstract:

    Friction-induced limit cycling deteriorates system performance in a wide variety of mechanical systems. In this paper, we study the way in which essential friction characteristics affect the occurrence and nature of friction-induced limit cycling in flexible rotor systems. This study is performed on the level of both numerical and experimental bifurcation analyses. Hereto, an experimental drill-string set-up is used. The synthesis of these numerical and experimental results confirms that friction-induced limit cycling is due to a subtle balance between a velocity weakening characteristic of the friction (Stribeck Effect) at lower velocities and viscous friction at higher velocities. Moreover, it is shown how these essential friction characteristics depend on physical conditions such as temperature and normal forces in the frictional contact in the experimental set-up.Copyright © 2005 by ASME