scholarly journals Observer Design for Estimation of Nonobservable States in Buildings

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
M. Długosz ◽  
J. Baranowski
Keyword(s):  
Temperature Control ◽  
Contraction Semigroup ◽  
Observer Design ◽  
State Variables ◽  
Control Applications ◽  
Fast Estimation ◽  
State Observers ◽  
Standard Observer ◽  
Efficient Control ◽  
Relevant Variables

Efficient temperature control requires more than air temperature measurements. Relevant variables, such as wall, ceiling, and other construction temperature evolution are usually unmeasured. Estimation of such quantities is often difficult because they are not observable with respect to available data. Their availability however would allow efficient control design. In this paper, we propose a method for designing state observers that efficiently estimate not only observable but also nonobservable (but detectable) state variables. Our method uses contraction semigroup, to obtain observer with a monotonic error reduction. Proposed approach gives twice as fast estimation as pure simulation and avoids transitional error standard observer would have. Problem of state estimation in building control applications is an important one. Attractiveness of obtaining values of physically unmeasurable variables is easily visible, as it would allow more efficient methods of temperature control. In this paper, authors discuss the problem of such estimation using a lumped capacitance model. This type of model is usually only detectable but not observable. Methods of observer tuning for such systems are not discussed properly in the literature and require special consideration. In this paper, three approaches for estimation are compared: pure model, eigenvalue shifting, and contraction semigroup observer. Results are illustrated with numerical experiments.

scholarly journals Observer Design for a Variable Moment of Inertia System

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5850
Author(s):  
Jerzy Baranowski
Keyword(s):  
Observer Design ◽  
Moment Of Inertia ◽  
Nonlinear Observer ◽  
Laboratory System ◽  
Systematic Testing ◽  
State Observers ◽  
Full State ◽  
Efficient Control ◽  
Linear Observer ◽  
Variable Moment

Variable moment of inertia systems are common, and a popular laboratory system of this type is the “ball-and-beam”. Such systems are, however, nonlinear and often unstable. Efficient control requires full state information (or at least partial velocities), which are generally difficult to measure. That is why the design of state observers is a relevant problem. In this paper, a new design of an observer is proposed. This new nonlinear observer uses partial output injection and the circle criterion to ensure semiglobal stability. Moreover, we present a complete modeling of the system and systematic testing of the observer in comparison to a baseline in the form of a linear observer. The results show that the designed observer outperforms its linear counterpart and does not impede control.

Observer Design for State Estimation of UV Curing Processes

2014 ◽  
Author(s):  
Adamu Yebi ◽  
Beshah Ayalew ◽  
Satadru Dey
Keyword(s):  
State Estimation ◽  
Online Monitoring ◽  
Uv Curing ◽  
Observer Design ◽  
Nonlinear Observer ◽  
Advanced Manufacturing ◽  
Monitoring And Control ◽  
State Observers ◽  
State Measurement ◽  
And Control

This article discusses the challenges of non-intrusive state measurement for the purposes of online monitoring and control of Ultraviolet (UV) curing processes. It then proposes a two-step observer design scheme involving the estimation of distributed temperature from boundary sensing cascaded with nonlinear cure state observers. For the temperature observer, backstepping techniques are applied to derive the observer partial differential equations along with the gain kernels. For subsequent cure state estimation, a nonlinear observer is derived along with analysis of its convergence characteristics. While illustrative simulation results are included for a composite laminate curing application, it is apparent that the approach can also be adopted for other UV processing applications in advanced manufacturing.

Output Adaptive Observers Design for Linear Non-Stationary Systems with Polynomial Parameters

2021 ◽  
Vol 22 (8) ◽  
pp. 404-410
Author(s):  
K. B. Dang ◽  
A. A. Pyrkin ◽  
A. A. Bobtsov ◽  
A. A. Vedyakov ◽  
S. I. Nizovtsev
Keyword(s):  
Linear Time ◽  
State Observer ◽  
Observer Design ◽  
Model Parameters ◽  
Time Varying ◽  
State Variables ◽  
Unknown Constant ◽  
Established Method ◽  
Time Varying Parameters ◽  
True Values

The article deals with the problem of state observer design for a linear time-varying plant. To solve this problem, a number of realistic assumptions are considered, assuming that the model parameters are polynomial functions of time with unknown coefficients. The problem of observer design is solved in the class of identification approaches, which provide transformation of the original mathematical model of the plant to a static linear regression equation, in which, instead of unknown constant parameters, there are state variables of generators that model non-stationary parameters. To recover the unknown functions of the regression model, we use the recently well-established method of dynamic regressor extension and mixing (DREM), which allows to obtain monotone estimates, as well as to accelerate the convergence of estimates to the true values. Despite the fact that the article deals with the problem of state observer design, it is worth noting the possibility of using the proposed approach to solve an independent and actual estimation problem of unknown time-varying parameters.

Impulsive finite-time observer design for uncertain positive linear systems with L2-gain analysis

2020 ◽  
Vol 42 (10) ◽  
pp. 1871-1881 ◽  
Author(s):  
Morteza Motahhari ◽  
Mohammad Hossein Shafiei
Keyword(s):  
Linear Systems ◽  
Finite Time ◽  
Estimation Error ◽  
Sufficient Conditions ◽  
The State ◽  
Observer Design ◽  
Linear Matrix ◽  
Time Interval ◽  
State Variables ◽  
L2 Gain

This paper is concerned with the design of a finite-time positive observer (FTPO) for continuous-time positive linear systems, which is robust regarding the L2-gain performance. In positive observers, the estimation of the state variables is always nonnegative. In contrast to previous positive observers with asymptotic convergence, an FTPO estimates positive state variables in a finite time. The proposed FTPO observer, using two Identity Luenberger observers and based on the impulsive framework, estimates exactly the state variables of positive systems in a predetermined time interval. Furthermore, sufficient conditions are given in terms of linear matrix inequalities (LMIs) to guarantee the L2-gain performance of the estimation error. Finally, the performance and robustness of the proposed FTPO are validated using numerical simulations.

CRONE Observer of Nonlinear SISO Systems

2007 ◽  
Author(s):  
Patrick Lanusse ◽  
Jocelyn Sabatier ◽  
Mathieu Merveillaut
Keyword(s):  
State Observer ◽  
Open Loop ◽  
Observer Design ◽  
Observation Error ◽  
Dynamic Feedback ◽  
Fractional Differentiation ◽  
State Observation ◽  
State Observers ◽  
Crone Control ◽  
Siso Systems

CRONE control, robust control methodology based on fractional differentiation, is applied to state observer design. State observation can indeed be viewed as a regulation problem given that the goal of a state observer is to cancel the observation error in spite of measurement noise, disturbances and plant perturbations. This conclusion has been used recently to define a new class of state observers known in the literature as “dynamic observers” or “input-output observer”. It is based on the observation error dynamic feedback. In this paper, this idea is used to define the CRONE observer design methodology for nonlinear SISO systems. As for CRONE control, fractional differentiation in the definition of an equivalent open loop transfer function permits the reduction of the number of parameters to be optimised.

scholarly journals Distributed Finite-Time State Estimation of Interconnected Complex Metabolic Networks

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-20
Author(s):  
Alfonso Sepulveda-Galvez ◽  
Jesus A. Badillo-Corona ◽  
Isaac Chairez
Keyword(s):  
Escherichia Coli ◽  
State Estimation ◽  
Finite Time ◽  
Metabolic Networks ◽  
Complex Structure ◽  
High Gain ◽  
Observer Design ◽  
Superior Performance ◽  
State Observers ◽  
Metabolic Behavior

A set of distributed robust finite-time state observers was developed and tested to estimate the main biochemical substances in interconnected metabolic networks with complex structure. The finite-time estimator was designed by composing several supertwisting based step-by-step state observers. This segmented structure was proposed accordingly to the partition of metabolic network obtained as a result of applying the observability analysis of the model used to represent metabolic networks. The observer was developed under the assumption that a sufficient and small number of intracellular compounds can be obtained by some feasible analytic techniques. These techniques are enlisted to demonstrate the feasibility of designing the proposed observer. A set of numerical simulations was proposed to test the observer design over the hydrogen producing metabolic behavior of Escherichia coli. The numerical evaluations showed the superior performance of the observer (on recovering immeasurable state values) over classical approaches (high gain). The variations of internal metabolites inserted in the hydrogen productive metabolic networks were collected from databases. This information supplied to the observer served to validate its ability to recover the time evolution of nonmeasurable metabolites.

A facility for precise temperature control applications in microgravity

1988 ◽  
Vol 8 (12) ◽  
pp. 61-68 ◽  
Author(s):  
M.E. Glicksman ◽  
E. Winsa ◽  
T.A. Lograsso ◽  
S.H. Tirmizi ◽  
R.C. Hahn ◽  
...  
Keyword(s):  
Temperature Control ◽  
Control Applications

OBSERVATION OF NONLINEAR VERTICUM-TYPE SYSTEMS APPLIED TO ECOLOGICAL MONITORING

2012 ◽  
Vol 05 (06) ◽  
pp. 1250051 ◽  
Author(s):  
S. MOLNÁR ◽  
M. GÁMEZ ◽  
I. LÓPEZ
Keyword(s):  
Design Method ◽  
Type System ◽  
Type Systems ◽  
Ecological Monitoring ◽  
Observer Design ◽  
Observation System ◽  
State Variables ◽  
Rank Condition ◽  
Decomposition Approach ◽  
Observation Systems

In this paper the concept of a nonlinear verticum-type observation system is introduced. These systems are composed from several "subsystems" connected sequentially in a particular way: a part of the state variables of each "subsystem" also appears in the next "subsystem" as an "exogenous variable" which can also be interpreted as a control generated by an "exosystem". Therefore, these "subsystems" are not observation systems, but formally can be considered as control-observation systems. The problem of observability of such systems can be reduced to rank conditions on the "subsystems". Indeed, under the condition of Lyapunov stability of an equilibrium of the "large", verticum-type system, it is shown that the Kalman rank condition on the linearization of the "subsystems" implies the observability of the original, nonlinear verticum-type system. For an illustration of the above linearization result, a stage-structured fishery model with reserve area is considered. Observability for this system is obtained by applying the above linearization and decomposition approach. Furthermore, it is also shown that, applying an appropriate observer design method to each subsystem, from the observation of the biomass densities of the adult (harvested) stage, in both areas, the biomass densities of the pre-recruit stage can be efficiently estimated.

Robust Piecewise-Linear State Observers for Flexible Link Mechanisms

2006 ◽  
Author(s):  
Roberto Caracciolo ◽  
Dario Richiedei ◽  
Alberto Trevisani
Keyword(s):  
Nonlinear Model ◽  
Closed Loop ◽  
Linear Models ◽  
Piecewise Linear ◽  
Equilibrium Points ◽  
Loop System ◽  
State Variables ◽  
Flexible Link ◽  
Closed Loop System ◽  
State Observers

This paper tackles the problem of designing state observers for flexible link mechanisms: an investigation is made on the possibility of employing observers making use of suitable piecewise-linear truncated dynamics models. A general approach is proposed, which provides an objective way of synthesizing observers preventing the instability that may arise from using reduced-order linearized models. The approach leads to the identification of the regions of the domain of the state variables where the linear approximations of the nonlinear model can be considered acceptable. To this purpose, first of all, the stability of the equilibrium points of the closed-loop system is assessed by applying the eigenvalue analysis to appropriate piecewise-linear models. Admittedly, the dynamics of such a closed-loop system is affected by the pole perturbation caused by spillover, and by the discrepancies between the linearized models of the plant and the one of the observer. Additionally, when nodal elastic displacements and velocities are not bounded in the infinitesimal neighborhoods of the equilibrium points, the difference between the nonlinear model and the locally-linearized one is expressed in terms of unstructured uncertainty and stability is assessed by H∞ robust analysis. The method is demonstrated by applying it to a closed-chain flexible link mechanism.

Sign in / Sign up

Export Citation Format

Share Document