Friction compensation as a fault-tolerant control problem

International Journal of Systems Science (Impact Factor: 2.1). 08/2010; 41(8):987-1001. DOI: 10.1080/00207720903434797
Source: DBLP

ABSTRACT The control of systems that involve friction presents interesting challenges. Recent research has focused on detailed modelling of friction phenomena in order to use robust on-line friction compensation procedures, attempting to cancel out the friction force effect in the feedback control of a mechanical or mechatronic system. However, the friction modelling problem remains a very difficult challenge and this article proposes a new approach to friction compensation which is based on the theory of robust fault estimation. The friction forces acting in a dynamic system can be viewed as actuator faults with time-varying characteristics to be estimated and compensated within an output feedback fault-tolerant control (FTC) scheme, so that the limitations arising from the use of a friction model are obviated. The friction (fault) estimation problem is hence embedded inside a control system with required stability, and performance robustness. This can be a significant advantage over well-known model-based friction compensation methods in which detailed modelling of friction phenomena is essential and for which robustness with respect to friction characteristics is difficult to achieve using non-linear models.

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    • "Traditionally safety critical systems have provided much of the main motivation for the development of the subject of FTC, however research during the last decade has shown that FTC methods represent promising approaches to handle several practical fault scenarios for real system applications. For example, in [6], FTC is utilised to compensate the effect of existing friction in mechatronic systems. In [7] FTC is used to enhance the performance of electromagnetic suspension system through tolerating the effect of air gap sensor fault and an accelerometer fault. "
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    ABSTRACT: The goal of this paper is to describe a novel fault tolerant tracking control (FTTC) strategy based on robust fault estimation and compensation of simultaneous actuator and sensor faults. Within the framework of fault tolerant control (FTC) the challenge is to develop an FTTC design strategy for nonlinear systems to tolerate simultaneous actuator and sensor faults that have bounded first time derivatives. The main contribution of this paper is the proposal of a new architecture based on a combination of actuator and sensor Takagi-Sugeno (T-S) proportional state estimators augmented with proportional and integral feedback (PPI) fault estimators together with a T-S dynamic output feedback control (TSDOFC) capable of time-varying reference tracking. Within this architecture the design freedom for each of the T-S estimators and the control system are available separately with an important consequence on robust L2 norm fault estimation and robust L2 norm closed-loop tracking performance. The FTTC strategy is illustrated using a nonlinear inverted pendulum example with time-varying tracking of a moving linear position reference
    International Journal of Control Automation and Systems 12/2013; 11(6):1149-1161. DOI:10.1007/s12555-013-0227-1 · 0.95 Impact Factor
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    • "A wide range of system applications exist in which fault estimation can be used to compensate faults within the control system (Patton, 1997); (Blanke et al, 2003); (Gao and Ding, 2007); (Gao et al, 2010); (Khedher et al, 2010), (Patton and Klinkhieo, 2009), (Patton and Klinkhieo, 2010); (Patton, Putra and Klinkhieo, 2010b) subject to fault-tolerance stability requirements. This class of systems belongs to the domain of active or direct FTC in which the combined problems of fault estimation and control compensation are frequently based on the use of linear system models. "
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    ABSTRACT: For systems that have no unique linearization equilibria, for example multi-link robot systems, the classical "direct" methods of Fault Tolerant Control (FTC) via fault estimation/compensation cannot easily be achieved via a linear time-invariant systems approach. This paper proposes an FTC strategy using an active fault estimator based on model reference control (MRC). The novelty lies in the combined use of on-line fault estimation and FTC design applied to a model reference system. The reference model is designed via pole-placement and the estimator design parameters are synthesized via a Linear Matrix Inequalities (LMIs) approach. An example of a non-linear two-link Manipulator (TLM) system is described to illustrate the design procedure.
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    • "A geometric approach for fault diagnosis in nonlinear systems is developed in [8]–[11]. Unknown input observers are developed in [10]–[12] to estimate the fault. These methods succeed to estimate/detect the faults for those cases where the frequency information of the fault does not have to be taken into account. "
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    ABSTRACT: Motorized antenna is a key element in overseas satellite telecommunication. The control system directs the on-board antenna toward a chosen satellite while the high sea waves disturb the antenna. Certain faults (communication system malfunction or signal blocking) cause interruption in the communication connection resulting in loss of the tracking functionality, and instability of the antenna. In this brief, a fault tolerant control (FTC) system is proposed for the satellite tracking antenna. The FTC system maintains the tracking functionality by employing proper control strategy. A robust fault diagnosis system is designed to supervise the FTC system. The employed fault diagnosis solution is able to estimate the faults for a class of nonlinear systems acting under external disturbances. Effectiveness of the method is verified through implementation and test on an antenna system.
    IEEE Transactions on Control Systems Technology 02/2011; 19(1-19):221 - 228. DOI:10.1109/TCST.2010.2040281 · 2.47 Impact Factor
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