An advanced criterion for optimal actuator and sensor placement on complex flexible structures
TL;DR: In this paper, an optimal placement of actuators and sensors for flexible mechanical systems is proposed to ensure a balance between low and high frequency modes, and at the same time applicability to complex systems in arbitrary system coordinates.
About: This article is published in IFAC Proceedings Volumes.The article was published on 2009-01-01. It has received 7 citations till now. The article focuses on the topics: Controllability & Observability.
Citations
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TL;DR: This paper formulate and analyse a framework in which two extra terms for penalising the number of actuators and sensors are incorporated into the variational formulations of controller synthesis problems in order to induce a favourable controller structure.
Abstract: When dealing with large-scale systems, manual selection of a subset of components (sensors/actuators), or equivalently identification of a favourable structure for the controller, that guarantees a certain closed-loop performance, is not very feasible. This paper is dedicated to the problem of concurrent optimal selection of actuators/sensors which can equivalently be considered as the structure identification for the controller. In the context of a multi-channel H2 dynamic output feedback controller synthesis, we formulate and analyse a framework in which we incorporate two extra terms for penalising the number of actuators and sensors into the variational formulations of controller synthesis problems in order to induce a favourable controller structure. We then develop an explicit scheme as well as an iterative process for the purpose of dealing with the multi-objective problem of controller structure and control law co-design. It is also stressed that the immediate application of the proposed a...
26 citations
23 Jun 2010
TL;DR: In this paper, the authors present a comprehensive robust ℋ ∞ -optimal control design methodology for complex flexible structures based on a pragmatic approach, where the control engineer produces an initial design and reuses it in subsequent design iterations and parameter optimization.
Abstract: Robust control design for complex flexible structures involves many consecutive essential steps. Additionally, many design parameters arise, which turn design optimization into a cumbersome and difficult task. This paper presents a comprehensive robust ℋ ∞ -optimal control design methodology for this class of systems. It relies on a pragmatic approach: The control engineer produces an initial design and reuses it in subsequent design iterations and parameter optimization. The methodology is illustrated by a large transport aircraft model and shows high potential to obtain and tune robust high-performance controllers. Expert knowledge and design decisions are introduced in a natural, clearly structured way, while control engineers are relieved from repetitive design tasks which are safely automated.
8 citations
Cites background from "An advanced criterion for optimal a..."
...Complex flexible structure systems can be transformed to modal form as outlined in [5] and [11]....
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TL;DR: The tasks of optimal actuator and sensor positioning, actuator sizing, and actuator bandwidth requirements are investigated, whereby solutions that are robust are sought with respect to parameter variations.
Abstract: This paper states an approach to actuator and sensor positioning optimization and design in the control system design of a large blended wing body (BWB) passenger aircraft. Numerous objectives have to be achieved by the control system: loads alleviation, vibration attenuation, and the fulfillment of handling quality requirements. Exploiting the system structure and existing system knowledge (excitation, comfort, and load formulations), evaluation criteria are designed to assess actuator and sensor effectiveness and efficiency for the aircraft dynamic range of interest. The tasks of optimal actuator and sensor positioning, actuator sizing, and actuator bandwidth requirements are investigated, whereby solutions that are robust are sought with respect to parameter variations. The results are shown on a BWB passenger aircraft model and verified using a normalized closed-loop performance assessment approach.
4 citations
Cites background or methods from "An advanced criterion for optimal a..."
...The relationship between the controller H2 norm and the design weight α is close to linearity in a loglog-scaling, so α can be found quickly (by few design iterations) by using a loglog-interpolation to obtain a target controller H2 norm....
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...This section reports the results obtained by applying the described methods to the described BWB aircraft system model....
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...The tasks of optimal actuator and sensor positioning, actuator sizing, and actuator bandwidth requirements are investigated, whereby solutions that are robust are sought with respect to parameter variations....
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TL;DR: This article addresses the issues of model reduction and actuator/sensor placement for flexible spacecraft with plant, actuator, and sensor faults by proposing a fault tolerant truncation method and a reconfiguration scheme based on the reduced-order faulty flexible spacecraft.
Abstract: This article addresses the issues of model reduction and actuator/sensor placement for flexible spacecraft with plant, actuator, and sensor faults. First, the sensitivity of controllability and observability with respect to faults is analyzed; Second, instead of a complete redesign of balanced truncation, a fault tolerant truncation method is proposed by estimating the bounds of Hankel singular value of faulty spacecraft and is fully based on the original balanced truncation structure; Third, a reconfiguration scheme of actuator/sensor placement is developed based on the reduced-order faulty flexible spacecraft.
3 citations
24 Jun 2009
TL;DR: Comparison to a state-of-the-art open-loop I/O selection method from literature verifies the proposed approach, but also shows that the closed-loop approach provides additional system insight and highly flexible applicability.
Abstract: One essential task in control system design is the optimal selection of inputs and outputs (I/O). In this paper a new concept for solving the I/O selection problem is proposed. It is based on normalized comparison of LQG closed loops, which are designed for each potential actuator/sensor separately. The LQG controller is iteratively tuned to obtain a prescribed and fixed value of a suitable system norm quantity. The proposed placement criterion is applied to flexible structures and demonstrated for an academic example and for a large-scale blended-wing-body (BWB) passenger aircraft pre-design model. Comparison to a state-of-the-art open-loop I/O selection method from literature verifies the proposed approach, but also shows that the closed-loop approach provides additional system insight and highly flexible applicability.
2 citations
Cites background from "An advanced criterion for optimal a..."
...If the designer tries not only to maximize energy transfer efficiency, but also seeks positions that guarantee a minimum controllability of all higher modes, the criterion has to be extended accordingly (this is done in [16])....
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References
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TL;DR: A set of criteria is proposed that a good IO selection method should possess, which is used to assess and compare the methods and it could be used as a guideline for new methods.
442 citations
TL;DR: In this article, a methodology is proposed for determination of actuator and sensor locations in motion control of flexible structures, which can be used before a control strategy is developed, relying on certain quantitative measures of degree of controllability and observability based on the controLLability and gramians, which are arrived at by considering the energies of the input and output under conditions of transient as well as persistent disturbances.
244 citations
TL;DR: A method for optimal positioning of piezoelectric actuators and sensors on a flexible structure and an energy based approach is developed, which leads quite naturally to the study of controllability and observability properties of the overall dynamical model.
Abstract: A method for optimal positioning of piezoelectric actuators and sensors on a flexible structure is presented. First, a two-dimensional (2-D) model of a piezoelectric actuator bonded to a plate is obtained. Then, a Ritz formulation is used to find a state model of the system in view of its control. To define an optimal positioning strategy, an energy based approach is developed. This leads quite naturally to the study of controllability and observability properties of the overall dynamical model. A new criterion based on energy assessment is proposed to locate actuators and sensors.
123 citations
13 Dec 1995
TL;DR: In this paper, the optimal location of sensors and actuators for both linear and nonlinear dynamical systems, in both the continuous-time and discrete-time case, on the basis of observability and controllability functions is discussed.
Abstract: In this paper, we discuss the optimal location of sensors and actuators for both linear and nonlinear dynamical systems, in both the continuous-time and discrete-time case, on the basis of observability and controllability functions. The optimal location of sensors can be viewed as the problem of maximizing the output energy generated by a given state. On the other hand, the optimal location of actuators can be viewed as the problem of minimizing the input energy required to reach a given state. Such design problems occur in many applications, such as the control of distributed parameter systems, arising in mechanical, hydraulic or chemical processes. In this paper, some new results on observability and controllability functions for nonlinear systems are also provided. Furthermore, we propose a general procedure for computing the optimal design parameters, based on both integer programming and a branch and bound method, suitable for large-scale systems. The effectiveness of this approach is demonstrated for a practical example.
113 citations
TL;DR: In this paper, a spatial H 2 norm-based computational scheme for finding the optimal locations of sensors and actuators in controlled flexible structures is proposed, where the authors use a genetic algorithm to solve the resulting nonlinear optimization problem.
93 citations