Optimal preview-based stable-inversion for output tracking of nonminimum-phase linear systems

2007 ◽  
Author(s):  
Qingze Zou
Keyword(s):  
Linear Systems ◽  
Nonminimum Phase ◽  
Output Tracking ◽  
Stable Inversion

Preview-Based Stable-Inversion for Output Tracking of Linear Systems

1999 ◽  
Vol 121 (4) ◽  
pp. 625-630 ◽  
Author(s):  
Qingze Zou ◽  
Santosh Devasia
Keyword(s):  
Linear Systems ◽  
Tracking Error ◽  
High Accuracy ◽  
Nonminimum Phase ◽  
Output Tracking ◽  
Stable Inversion ◽  
Nonminimum Phase Systems ◽  
Phase Systems ◽  
Inversion Techniques ◽  
Planning Problems

Stable Inversion techniques can be used to achieve high-accuracy output tracking. However, for nonminimum phase systems, the inverse is noncausal—hence the inverse has to be precomputed using a prespecified desired-output trajectory. This requirement for prespecification of the desired output restricts the use of inversion-based approaches to trajectory planning problems (for nonminimum phase systems). In the present article, it is shown that preview information of the desired output can be used to achieve online inversion-based output-tracking of linear systems. The amount of preview-time needed is quantified in terms of the tracking error and the internal dynamics of the system (zeros of the system). The methodology is applied to the online output tracking of a flexible structure and experimental results are presented.

Preview-Based Output Tracking of Nonminimum-Phase Linear Systems via Trajectory Decomposition: Nanomanipulation Example

2010 ◽  
Author(s):  
Haiming Wang ◽  
Kyongsoo Kim ◽  
Qingze Zou ◽  
Hongbing Xu
Keyword(s):  
Control Technique ◽  
Control Input ◽  
Nonminimum Phase ◽  
Output Tracking ◽  
Actuation Time ◽  
Stable Inversion ◽  
Inversion Technique ◽  
Nonminimum Phase Systems ◽  
Phase Systems ◽  
Trajectory Decomposition

In this article, a trajectory-decomposition-based approach to output tracking with preview for nonminimum-phase systems is proposed. When there exists a finite (in time) preview of the future desired trajectory, precision output tracking of nonminimum-phase systems can be achieved by using the preview-based stable-inversion technique. The preview-based stable-inversion technique has been successfully implemented in various high-speed positioning applications. The performance of this approach, however, can become sensitive to system dynamics uncertainty. Moreover, the computation involved in the implementation of this approach can be demanding. In the proposed approach, such preview-based inversion related challenges are addressed by integrating the notion of signal decomposition and the iterative learning control technique together. Particularly, a library of desired output elements and their corresponding control input elements is constructed, and the ILC techniques such as the recently-developed model-less inversion-based iterative control (MIIC) are used to obtain the control input elements that achieve precision output tracking of the corresponding desired output elements. Then the previewed future desired trajectory is decomposed as a summation of desired output elements, and the control input is synthesized by using the input elements selected for the corresponding output elements with chosen pre-actuation time. Furthermore, the required pre-actuation time is quantified based on the stable-inversion theory. The proposed approach is illustrated through simulation study of a nanomanipulation application using a nonminimum-phase piezo actuator model.

-spline-decomposition-based output tracking with preview for nonminimum-phase linear systems

Automatica ◽  
2013 ◽  
Vol 49 (5) ◽  
pp. 1295-1303 ◽  
Author(s):  
Haiming Wang ◽  
Kyongsoo Kim ◽  
Qingze Zou
Keyword(s):  
Linear Systems ◽  
Nonminimum Phase ◽  
Output Tracking
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