Searching for Robust Minimal-Order Compensators

1999 ◽  
Vol 123 (2) ◽  
pp. 233-236 ◽  
Author(s):  
Qian Wang ◽  
Robert F. Stengel
Keyword(s):  
Transfer Function ◽  
Design Procedure ◽  
Minimal Order ◽  
Single Input Single Output ◽  
Single Output ◽  
Parameter Variations ◽  
Single Input ◽  
Monte Carlo Evaluation ◽  
And Performance ◽  
Algorithm Search

A method of designing a family of robust compensators for a single-input/single-output linear system is presented. Each compensator’s transfer function is found by using a genetic-algorithm search for numerator and denominator coefficients. The search minimizes the probabilities of unsatisfactory stability and performance subject to real parameter variations of the plant. As the search progresses, probabilities are estimated by Monte Carlo evaluation. The design procedure employs a sweep from the lowest feasible transfer-function order to higher order, terminating either when design goals have been achieved or when no further improvement in robustness is evident. The method provides a means for estimating the best possible compensation of a given order based on repeated searches.

Design of Single-Input-Single-Output Compliant Mechanisms for Practical Applications Using Selection Maps

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Sudarshan Hegde ◽  
G. K. Ananthasuresh
Keyword(s):  
Compliant Mechanisms ◽  
Material Selection ◽  
Design Procedure ◽  
Single Input Single Output ◽  
Practical Applications ◽  
Beam Elements ◽  
Single Output ◽  
Out Of Plane ◽  
Single Input ◽  
Interactive Map

We present an interactive map-based technique for designing single-input-single-output compliant mechanisms that meet the requirements of practical applications. Our map juxtaposes user-specifications with the attributes of real compliant mechanisms stored in a database so that not only the practical feasibility of the specifications can be discerned quickly but also modifications can be done interactively to the existing compliant mechanisms. The practical utility of the method presented here exceeds that of shape and size optimizations because it accounts for manufacturing considerations, stress limits, and material selection. The premise for the method is the spring-leverage (SL) model, which characterizes the kinematic and elastostatic behavior of compliant mechanisms with only three SL constants. The user-specifications are met interactively using the beam-based 2D models of compliant mechanisms by changing their attributes such as: (i) overall size in two planar orthogonal directions, separately and together, (ii) uniform resizing of the in-plane widths of all the beam elements, (iii) uniform resizing of the out-of-plane thicknesses of the beam elements, and (iv) the material. We present a design software program with a graphical user interface for interactive design. A case-study that describes the design procedure in detail is also presented while additional case-studies are posted on a website.

Active Vibration Isolation of Metrology Frames; A Modal Decoupled Control Design

2005 ◽  
Vol 127 (3) ◽  
pp. 223-233 ◽  
Author(s):  
Marcel Heertjes ◽  
Koen de Graaff ◽  
Jan-Gerard van der Toorn
Keyword(s):  
Vibration Isolation ◽  
Isolation System ◽  
Single Input Single Output ◽  
Single Output ◽  
System A ◽  
Active Vibration ◽  
Single Input ◽  
And Performance ◽  
Six Degree Of Freedom ◽  
Active Vibration Isolation

For a six degree-of-freedom active vibration isolation system, a control strategy based on modal decoupling is proposed. This has the advantage of controlling the modal directions on a centralized single-input single-output basis. As a consequence, stability and performance can be imposed in each of the modal directions separately. An experimental demonstration is given using a dummy metrology frame. That is, a 1600 kg payload mass supported by three combined pneumatic and Lorentz controlled isolators. With this setup, two unstable modal directions resulting from a high center of gravity are stabilized without compromising performance in any of the remaining directions. In fact, performance in the remaining directions is enhanced using manual loop shaping.

Robust non-destructive inspection of composite aerospace structures by extraction of ultrasonic guided-wave transfer function in single-input dual-output scanning systems

2020 ◽  
Vol 31 (5) ◽  
pp. 651-664 ◽  
Author(s):  
Margherita Capriotti ◽  
Francesco Lanza di Scalea
Keyword(s):  
Transfer Function ◽  
Guided Wave ◽  
Single Input Single Output ◽  
Aircraft Fuselage ◽  
Single Output ◽  
Ultrasonic Guided Wave ◽  
Single Input ◽  
Non Destructive ◽  
Scanning Systems

Ultrasonic guided-wave testing is widely utilized for damage detection in plate-like structural components, including composite aircraft fuselage and wing panels. Many guided-wave tests involve transducer scanning to cover finite areas, a task that is most effectively performed by non-contact wave transduction means. The most common guided-wave test implementation consists of a “single-input single-output” scheme. The single-input single-output scheme leads to a transfer function that is convolved with the particular frequency response of the transducers and that of the transducer-to-structure paths (in both excitation and detection). These responses can be unknown or generally variable, especially in non-contact scanning systems and impact excitations. This article proposes a “single-input dual-output” scheme for ultrasonic guided-wave testing in scanning systems that is based on a deconvolution operation. The single-input dual-output scheme better isolates the structural transfer function that is the only property affected by the presence of possible damage. The single-input dual-output scheme was applied to two guided-wave scanning systems under development to detect impact-type damage in stiffened skin-to-stringer panels representative of modern composite aircraft construction. The results demonstrate the dual-output technique and also shed some light on the role of the different frequency bands for the detection of damage at different locations of the skin-to-stringer assembly.

Robust polynomial eigenstructure assignment using dynamic feedback controllers

1997 ◽  
Vol 211 (1) ◽  
pp. 35-51 ◽  
Author(s):  
B A White
Keyword(s):  
Eigenstructure Assignment ◽  
Systematic Design ◽  
Dynamic Feedback ◽  
Feedback Controllers ◽  
Single Input Single Output ◽  
Single Output ◽  
Stability Robustness ◽  
Single Input ◽  
And Performance ◽  
Value Decomposition

This paper presents a dynamic controller format for use in polynomial eigenstructure assignment. It formulates the controller in singular-value decomposition format, which enables the designer to use simple SISO (single-input, single-output) compensators, together with direction matrices to construct the controller. The technique utilizes the root locus to evaluate stability and performance. It also introduces several metrics for decoupling, disturbance rejection, actuator movement and stability robustness in a graphical manner that allows a systematic design to be carried out. The paper also includes a two-input, two-output design example to illustrate the technique.

Comparative analysis of SISO and wavelength diversity-based FSO systems at different transmitter power levels

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Varun Srivastava ◽  
Abhilash Mandloi ◽  
Dhiraj Kumar Patel
Keyword(s):  
Optical Signal ◽  
Free Space Optical ◽  
Optical Source ◽  
Transmit Power ◽  
Single Input Single Output ◽  
Transmitter Power ◽  
Single Output ◽  
Communication Links ◽  
Single Input ◽  
Matching Performance

AbstractFree space optical (FSO) communication refers to a line of sight technology, which comprises optical source and detector to create a link without the use of physical connections. Similar to other wireless communication links, these are severely affected by losses that emerged due to atmospheric turbulence and lead to deteriorated intensity of the optical signal at the receiver. This impairment can be compensated easily by enhancing the transmitter power. However, increasing the transmitter power has some limitations as per radiation regulations. The requirement of high transmit power can be reduced by employing diversity methods. This paper presents, a wavelength-based diversity method with equal gain combining receiver, an effective technique to provide matching performance to single input single output at a comparatively low transmit power.

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