2015 |
Aneel Tanwani / Hyungbo Shim / Daniel Liberzon Comments on “Observability of Switched Linear Systems: Characterization and Observer Design” Journal Article In: IEEE Transactions on Automatic Control, vol. 60, no. 12, pp. 3396-3400, 2015. Abstract | Links | BibTeX | Tags: Linear system @article{TanwaniShimLiberzon15,This note points out certain limitations of our results from the paper mentioned in the title, and provides a modified approach to overcome these limitations. Specifically, the observer design addressed in the aforementioned paper is, in general, only applicable to switched linear systems with invertible state reset maps and this note presents a modified algorithm for state estimation that can also handle non-invertible state reset maps. In the process, we also identify some equalities from that paper which may not hold in general for arbitrary state reset maps. |
2013 |
Chanhwa Lee / Zhaowu Ping / Hyungbo Shim On-line Switching Signal Estimation of Switched Linear Systems with Measurement Noise Proceedings Article In: In this paper, we study a switching signal estimation problem for continuous time switched linear control systems with measurement noise. Inspired by the work of [8], we first propose a generalized minimum distance criterion to estimate the active mode of the plant with inputs. Then we propose an implementable on-line robust switching signal estimation algorithm to detect the switching time with guaranteed precision, where some update condition and threshold condition are checked all the time. Under the update and threshold conditions, we detect the switching time within a predetermined time interval after the switching occurred., pp. 2180-2185, IEEE, Zurich, Switzerland, 2013. Abstract | Links | BibTeX | Tags: Estimation theory, Linear system @inproceedings{LeePingShim13,In this paper, we study a switching signal estimation problem for continuous time switched linear control systems with measurement noise. Inspired by the work of [8], we first propose a generalized minimum distance criterion to estimate the active mode of the plant with inputs. Then we propose an implementable on-line robust switching signal estimation algorithm to detect the switching time with guaranteed precision, where some update condition and threshold condition are checked all the time. Under the update and threshold conditions, we detect the switching time within a predetermined time interval after the switching occurred. |
Aneel Tanwani / Hyungbo Shim / Daniel Liberzon Observability for Switched Linear Systems: Characterization and Observer Design Journal Article In: IEEE Transactions on Automatic Control, vol. 58, no. 4, pp. 891-904, 2013. Abstract | Links | BibTeX | Tags: Linear system, Time-varying system @article{TanwaniShimLiberzon13,This paper presents a characterization of observability and an observer design method for switched linear systems with state jumps. A necessary and sufficient condition is presented for observability, globally in time, when the system evolves under predetermined mode transitions. Because this characterization depends upon the switching signal under consideration, the existence of singular switching signals is studied alongside developing a sufficient condition that guarantees uniform observability with respect to switching times. Furthermore, while taking state jumps into account, a relatively weaker characterization is given for determinability, the property that concerns with recovery of the original state at some time rather than at all times. Assuming determinability of the system, a hybrid observer is designed for the most general case to estimate the state of the system and it is shown that the estimation error decays exponentially. Since the individual modes of the switched system may not be observable, the proposed strategy for designing the observer is based upon a novel idea of accumulating the information from individual subsystems. Contrary to the usual approach, dwell-time between switchings is not necessary, but the proposed design does require persistent switching. For practical purposes, the calculations also take into account the time consumed in performing computations. |
2012 |
Jaeyong Kim / Jongwook Yang / Jung-Su Kim / Hyungbo Shim Practical Consensus for Heterogeneous Linear Time-Varying Multi-Agent Systems Proceedings Article In: Proc. of 2012 12th International Conference on Control, Automation and Systems (ICCAS), pp. 23-28, IEEE, JeJu Island, South Korea, 2012. Abstract | BibTeX | Tags: Linear system, Time-varying system @inproceedings{KimYangKimShim12,This paper studies practical consensus (PC) problem for linear multi-agent systems (MAS) under a fixed, connected, and undirected communication network. PC means that the difference between any two agents remains in an arbitrarily chosen neighborhood of the origin after some time by using a suitable control law. All the agents, which are heterogeneous first-order linear time-varying (LTV) systems, can collect only relative state information from their neighborhoods. According to the assumptions of MAS, we divide the problem into two cases; one is a class of homogeneous LTV MAS with heterogeneous disturbances where the difference between any two disturbances is bounded, and the other is a class of heterogeneous LTV MAS with heterogeneous bounded disturbances. Finally, we show that PC for each case is always achieved if the control gain is sufficiently large. |
2005 |
Young Ik Son / Hyungbo Shim / Nam Hoon Jo / Kab-II Kim A new approach to design of a dynamic output feedback stabilizing control law for LTI systems Journal Article In: Journal of Mechanical Science and Technology, vol. 19, no. 2, pp. 618-624, 2005, ISSN: 1738-494X. Abstract | Links | BibTeX | Tags: Linear system @article{SonShimJoKim05,We present a new state-space approach to construct a dynamic output feedback controller which stabilizes a class of linear time invariant systems All the states of the given system are not measurable and only the output is used to design the stabilizing control law In the design scheme, however, we first assume that the given system can be stabilized by a feedback law composed of the output and its derivatives of a certain order Beginning with this assumption, we systematically construct a dynamic system which removes the need of the derivatives The mam advantage of the proposed controller is regarding the controller order, which may be smaller than that of conventional output feedback controller Using a simple numerical example, it is shown that the order of the proposed controller is indeed smaller than that of reduced-order observer based output feedback controller |
List of English Publication
2015 |
Comments on “Observability of Switched Linear Systems: Characterization and Observer Design” Journal Article In: IEEE Transactions on Automatic Control, vol. 60, no. 12, pp. 3396-3400, 2015. |
2013 |
On-line Switching Signal Estimation of Switched Linear Systems with Measurement Noise Proceedings Article In: In this paper, we study a switching signal estimation problem for continuous time switched linear control systems with measurement noise. Inspired by the work of [8], we first propose a generalized minimum distance criterion to estimate the active mode of the plant with inputs. Then we propose an implementable on-line robust switching signal estimation algorithm to detect the switching time with guaranteed precision, where some update condition and threshold condition are checked all the time. Under the update and threshold conditions, we detect the switching time within a predetermined time interval after the switching occurred., pp. 2180-2185, IEEE, Zurich, Switzerland, 2013. |
Observability for Switched Linear Systems: Characterization and Observer Design Journal Article In: IEEE Transactions on Automatic Control, vol. 58, no. 4, pp. 891-904, 2013. |
2012 |
Practical Consensus for Heterogeneous Linear Time-Varying Multi-Agent Systems Proceedings Article In: Proc. of 2012 12th International Conference on Control, Automation and Systems (ICCAS), pp. 23-28, IEEE, JeJu Island, South Korea, 2012. |
2005 |
A new approach to design of a dynamic output feedback stabilizing control law for LTI systems Journal Article In: Journal of Mechanical Science and Technology, vol. 19, no. 2, pp. 618-624, 2005, ISSN: 1738-494X. |