Robust Discrete-Time Output Tracking Controller Design for Nonminimum Phase Systems

Exact output tracking requires preview information of the desired output for nonminimum-phase systems. For situations when preview information is not available, this article proposes an output-boundary regulation (OBR) approach that maintains the output-tracking error within prescribed bounds for nonlinear nonminimum-phase systems. OBR transitions the output-tracking error to zero whenever the output error reaches a set magnitude using polynomial output trajectories for each transition. The main contribution is to show that an output-transition-based OBR (O-OBR, which uses post-actuation input to transition the system state after the output-error transition is completed) can enable OBR of more aggressive output trajectories when compared to a state-transition-based OBR (S-OBR) that transitions the full system state and therefore achieves the output transition as well. Results from an example simulation system is used to illustrate the proposed OBR approach and comparatively evaluate the S-OBR and O-OBR approaches, which show that, for the example system, the O-OBR can track 3 times faster desired output trajectory than the S-OBR approach.

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Output Tracking of Nonlinear Nonminimum Phase Systems: an Engineering Solution

Proceedings of the 44th IEEE Conference on Decision and Control ◽

10.1109/cdc.2005.1582698 ◽

2006 ◽

Cited By ~ 1

Author(s):

Dong Li

Keyword(s):

Nonminimum Phase ◽

Output Tracking ◽

Engineering Solution ◽

Nonminimum Phase Systems ◽

Phase Systems

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Precision Tracking Control of Discrete Time Nonminimum-Phase Systems

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2899027 ◽

1993 ◽

Vol 115 (2A) ◽

pp. 238-245 ◽

Cited By ~ 16

Author(s):

Chia-Hsiang Menq ◽

Jin-jae Chen

Keyword(s):

Discrete Time ◽

Tracking Control ◽

Tracking Performance ◽

Nonminimum Phase ◽

Nonminimum Phase Systems ◽

Control Scheme ◽

Feedforward Controller ◽

Precision Tracking ◽

Phase Systems ◽

Precision Tracking Control

In this paper, a precision tracking control scheme for linear discrete time nonminimum-phase systems is proposed. This control scheme consists of a preview filter, a tracking-performance filter, a command feedforward controller, and a feedback controller. A command feedforward controller, whose design is based on the minimal order inverse model of the plant being controlled, will result in a completely decoupled system. The preview filter is introduced to compensate the phase and gain errors induced by the nonminimum phase zeros or lightly damped zeros of the system. Using the command feedforward controller along with the proposed preview filter, the tracking performance of the proposed control scheme can be characterized by the frequency response of the tracking-performance filter. For the design of the preview filter, a generalized Nth order preview filter and its associated penalty function that quantifies the tracking error of a design are defined. It is shown that, given the desired bandwidth and the order of the preview filter, the optimal solution for the design of the preview filter can be obtained explicitly. The proposed control scheme together with the optimal preview filter is shown to be very effective in achieving precision tracking control of discrete time MIMO nonminimum phase systems. It is also shown that the tracking performance is improved as the order N of the preview filter is increased.

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