Development of Stability/Robustness Considerations for Control System Design with Multiple Input/Multiple Output Plants

1988 ◽  
Author(s):  
Daniel J. Hurdle
Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 487
Author(s):  
Fumitake Fujii ◽  
Akinori Kaneishi ◽  
Takafumi Nii ◽  
Ryu’ichiro Maenishi ◽  
Soma Tanaka

Proportional–integral–derivative (PID) control remains the primary choice for industrial process control problems. However, owing to the increased complexity and precision requirement of current industrial processes, a conventional PID controller may provide only unsatisfactory performance, or the determination of PID gains may become quite difficult. To address these issues, studies have suggested the use of reinforcement learning in combination with PID control laws. The present study aims to extend this idea to the control of a multiple-input multiple-output (MIMO) process that suffers from both physical coupling between inputs and a long input/output lag. We specifically target a thin film production process as an example of such a MIMO process and propose a self-tuning two-degree-of-freedom PI controller for the film thickness control problem. Theoretically, the self-tuning functionality of the proposed control system is based on the actor-critic reinforcement learning algorithm. We also propose a method to compensate for the input coupling. Numerical simulations are conducted under several likely scenarios to demonstrate the enhanced control performance relative to that of a conventional static gain PI controller.


Author(s):  
Zhongxiang Chen ◽  
Tatsuya Sakanushi ◽  
Kou Yamada ◽  
Yun Zhao ◽  
Satoshi Tohnai

The modified repetitive control system is a type of servomechanism for a periodic reference input. When modified repetitive control design methods are applied to real systems, the influence of uncertainties in the plant must be considered. In some cases, uncertainties in the plant make the modified repetitive control system unstable, even though the controller was designed to stabilize the nominal plant. Recently, the parameterization of all robust stabilizing modified repetitive controllers was obtained by Yamada et al. In addition, Yamada et al. proposed the parameterization of all robust stabilizing modified repetitive controllers for time-delay plants. However, no paper has proposed the parameterization of all robust stabilizing modified repetitive controllers for multiple-input/multiple-output time-delay plants. In this paper, we expand the result by Yamada et al. and propose the parameterization of all robust stabilizing modified repetitive controllers for multipleinput/multiple-output time-delay plants.


Author(s):  
Yun Zhao ◽  
Kou Yamada ◽  
Tatsuya Sakanushi ◽  
Satoshi Tohnai

The modified repetitive control system is a type of servomechanism for a periodic reference input. When modified repetitive control design methods are applied to real systems, the influence of uncertainties in the plant must be considered. In some cases, uncertainties in the plant make the control system unstable, even though the controller was designed to stabilize the nominal plant. Recently, Chen et al. propose the parameterization of all robust stabilizingmodified repetitive controllers for multipleinput/ multiple-output time-delay plants. However, using their method, it is complex to specify the lowpass filter in the internal model for the periodic reference input of which the role is to specify the inputoutput characteristic. Because, the low-pass filter is related to four free parameters in the parameterization. To specify the input-output characteristic easily, this paper proposes the parameterization of all robust stabilizing modified repetitive controllers for multiple-input/multiple-output time-delay plants with specified input-output characteristic such that the input-output characteristic can be specified beforehand.


2010 ◽  
Vol 36 ◽  
pp. 273-281 ◽  
Author(s):  
Kou Yamada ◽  
Tatsuya Sakanushi ◽  
Takaaki Hagiwara ◽  
Iwanori Murakami ◽  
Yoshinori Ando ◽  
...  

In this paper, we examine the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic. The parameterization of all stabilizing modified repetitive controllers for non-minimum phase systems was solved by Yamada et al. However, when we design a stabilizing modified repetitive controller using the parameterization by Yamada et al., the input-output frequency characteristic of the control system cannot be settled so easily. The input-output frequency characteristic of the control systems is required to be easily settled. This problem is solved by obtaining the parameterization of all stabilizing modified repetitive controllers with the specified input-output frequency characteristic. However, no paper has proposed the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic. In this paper, we propose the parameterization of all stabilizing modified repetitive controllers for multiple-input/multiple-output plants with the specified input-output frequency characteristic.


2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Hai Jiang ◽  
Hongjun Song ◽  
Lei Guo ◽  
Wei Wang

The paper proposes special multiple-input single-output synthetic aperture radar (MISO-SAR) and multiple-input multiple-output SAR (MIMO-SAR) for bidirectional imaging, which can simultaneously illuminate two areas from different directions in azimuth. For the proposed MISO-SAR, two subpulses with the same carrier frequency and phase coding are transmitted with different azimuth directions by switching the phase coefficients in the transmit modules, and echoes corresponding to the subpulses are received by the main lobe and the first grating lobe of the whole antenna. To suppress mutual interference, the two subpulses are transmitted with different range-frequency bands, and their echoes are demodulated and recorded in different channels in the proposed MIMO-SAR. This paper presents the system design of these modes and analyzes their azimuth ambiguity to signal ratio (AASR). Besides, simulation results on points are carried out to validate the proposed bidirectional imaging modes.


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