Generic properties and control of linear structured systems: a survey

This paper concerns structured systems, namely linear systems where the state-space matrices have zeros in some fixed positions, and free parameters in all other entries. In particular, it focuses on discrete-time linear time-invariant systems affected by an unknown input. The goal is to study delay-L left invertibility, namely the possibility to reconstruct the input sequence from the output sequence, assuming that the initial state is known, and requiring that the inputs can be reconstructed at least up to L time steps before the current output. Under the assumption that the unknown input is scalar, this paper presents a simple graphical condition characterizing the structured systems which are generically delay-L left invertible.

Input-output decoupling and disturbance rejection problems in structural analysis

Multipurpose deadbeat controller synthesis in m-dimensional discrete multivariable systems

Notice of Violation of IEEE Publication Principles<br><br>"System Model and Controller Design of an Inverted Pendulum"<br>by Baoping Xiao, Chang Xu, and Lijun Xu<br>in the Proceedings of the 2009 Second International Conference on Industrial and Information Systems, April 2009, pp 356-359<br><br>After careful and considered review of the content and authorship of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE's Publication Principles.<br><br>This paper is a near verbatim copy of the work cited below. The original text and figures were copied without attribution (including appropriate references to the original author(s) and/or paper title) and without permission.<br><br>Due to the nature of this violation, reasonable effort should be made to remove all past references to this paper, and future references should be made to the following article:<br><br>"The Inverted Pendulum"<br>by John Stang,<br>as a Student Project: ECE691, May 2005<br> http://instruct1.cit.cornell.edu/courses/eceprojectsland/STUDENTPROJ/2004to2005/jss67/index.html<br><br> <br/> The inverted pendulum is a classical control problem, which involves developing a system to balance a pendulum. For visualization purposes, this is similar to trying to balance a broomstick on a finger. There are three main subsystems that compose this design including the mechanical system, the feedback network which includes sensors and a method to read them, and a controller and its interface to the mechanical system. The system model, state space representation and controller design is described, the model is converted into state space form, and is used to design a controller using the Linear Quadratic Regulator (LQR) cost equation. The final system results in a cart that could balance a pendulum for a limited amount of time. This was due to many imperfections in the mechanical system and the inability to model the dynamics of these imperfections along with the calculation limitations of the Atmel Mega32.

Digraph Programs for Multivariable Control

On Absolute Stability of Lur’e Control Systems with Multiple Non-Linearities

Offshore compliant structures such as guyed platforms, tension leg platforms and articulated towers are economically attractive for deep water conditions because of their reduced structural weight compared to conventional platforms. The foundations of these kinds of structures do not resist lateral environmental loads forces; instead, restoring moments are provided by a large buoyancy force, a set of guylines or a combination of both. These structures have a fundamental frequency well below the ocean wave’s lower frequency-bound. As a result of the relatively large displacements, geometric nonlinearity is an important consideration in the analysis of such a structure. This paper presents a literature review on offshore compliant structures. The review focuses on the static and dynamic response of the structure due to various environmental conditions, such as wind, waves and current. Emphasis is placed on modeling techniques and methods of solution. Many modeling and analysis techniques are common to the aerospace and ocean engineering communities due to the similarities in structural and environmental complexities. For example, aerodynamic loads on offshore platforms are a significant part of any analysis. Also, fluid loading models bear great similarities to mechanistic wind loading models. It is in this vein that a review paper with the focus on offshore structures is included in a journal of aerospace engineering.

The problem of controlling large scale economic systems has led to the introduction of the state space forms as an alternative representation of traditional model forms in various theoretical and empirical studies of dynamic economic systems, especially in the application of optimal decision rules for macroeconomic planning and policy models. The application of optimal control techniques to macroeconomics has demonstrated the potential of optimal control theory for macroeconomic growth theory, development and stabilisation (Shell (1967), Kendrick and Taylor (1970), Dobell and Ho (1967)). To open up the field of econometric modelling to the techniques of optimal control econometric models, in either structural, reduced or final form, have usually been translated into state space form; see for example Preston and Wall (1973).KeywordsInterconnected SystemState Space FormDegenerate SystemTime Scale SeparationOptimal Decision RuleThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Gimbals are mechatronic systems well known for their use in the stabilization of cameras which are under the effect of sudden movements. Gimbals help keeping cameras at previously defined fixed orientations, so that the captured images have the highest quality. This paper focuses on the design of a Linear Quadratic Gaussian, LQG, controller, based on the physical modeling of a commercial Gimbal with two degrees of freedom (2DOF), which is used for first-person applications in unmanned aerial vehicle (UAV). This approach is proposed to make a more realistic representation of the system under study, since it guarantees high accuracy in the simulation of the dynamic response, as compared to the prediction of the mathematical model of the same system. The development of the model starts by sectioning the Gimbal into a series of interconnected links. Subsequently, a fixed reference system is assigned to each link body and the corresponding homogeneous transformation matrices are established, which will allow the calculation of the orientation of each link and the displacement of their centers of mass. Once the total kinetic and potential energy of the mechanical components are obtained, Lagrange’s method is utilized to establish the mathematical model of the mechanical structure of the Gimbal. The equations of motion of the system are then expressed in state space form, with two inputs, two outputs and four states, where the inputs are the torques produced by each one of the motors, the outputs are the orientation of the first two links, and the states are the aforementioned orientations along with their time derivatives. The state space model was implemented in MATLAB’s Simulink environment to compare its prediction of the transient response with the prediction obtained with the representation of the same system using MATLAB’s SimMechanics physical modelling interface. The mathematical model of each one of the three-phase Brushless DC motors is also expressed in state space form, where the three inputs of each motor model are the voltages of the corresponding motor phases, its two outputs are the angular position and angular velocity, and its four states are the currents in two of the phases, the orientation of the motor shaft and its rate of change. This model is experimentally validated by performing a switching sequence in both the simulation model and the physical system and observing that the transient response of the angular position of the motor shaft is in accordance with the theoretical model. The control system design process starts with the interconnection of the models of the mechanical components and the models of the Brushless DC Motor, using their corresponding state space representations. The resulting model features six inputs, two outputs and eight states. The inputs are the voltages in each phase of the two motors in the Gimbal, the outputs are the angular positions of the first two links, and the states are the currents in two of the phases for each motor and the orientations of the first two links, along with their corresponding time derivatives. An optimal LQG control system is designed using MATLAB’s dlqr and Kalman functions, which calculate the gains for the control system and the gains for the states estimated by the observer. The external excitation in each of the phases is carried out by pulse width modulation. Finally, the transient response of the overall system is evaluated for different reference points. The simulation results show very good agreement with the experimental measurements.

A simple and direct deadbeat control design algorithm for discrete-time multivariable systems is introduced. Our brief was to synthesize a realizable controller to achieve the following objectives: (1) input-output decoupling, (2) deadbeat tracking of any prespecified class of changeable deterministic reference signals and (3) changeable deterministic disturbances rejection where the changeable reference signals and disturbances can be different at each channel. Since the internal stability requirement is satisfied, our design algorithm can easily handle both unstable and non-minimum phase systems. Some constraints on the transfer function are also derived to make sure that the derived controller is realizable. Since all solutions can be described in parametric form, some of the performance criteria can be combined.

The Data Collection System for Prospective Citizens and Residents (Trainers) in the Setia Hati Brotherhood in the Pekanbaru Branch still uses a manual system. Where paper becomes a means in data collection and data information sources. The rapid development of technology in the current era of globalization that can facilitate all respects, including data collection of information that can make data collection more effective and efficient. PSHT Pekanbaru Branch corrects the problem in this data collection to make data collection faster because the system has not been computerized. The data collection in the PSHT Pekanbaru Branch requires a new system so that the system can be improved. As for the system carried out by the writer who discusses structured development systems using the waterfall method, as well as analysis and design tools using the Unified Modeling Language (UML). As for the implementation, some software is published using the framework framework , the code editor uses Atom, the PHP package uses XAMPP version 3.2.4 (PHP 7.3.9, Apache web server 2.4.7 and MySQL database version 5.0.12) and which the last web browser using Google Chrome

Robot software controllers are often concurrent and time critical, and requires modern engineering approaches for validation and verification. With this motivation, we have developed a tool and techniques for graphical modelling with support for automatic generation of underlying mathematical definitions for model checking. It is possible to check automatically both general properties, like absence of deadlock, and specific application properties. We cater both for timed and untimed modelling and verification. Our approach has been tried in examples used in a variety of robotic applications.

The growing digital consumerism in modern society is associated with higher expectations of customer experience, and as such the business environment is expected to co-evolve by developing more consumer-centric, sharing-based and fastpaced business models. This calls for deeper understanding of consumer aspirations and preferences in a given local context. Therefore, this paper explores the co-evolutionary dynamics of digital financial inclusion of Generation Z against a backdrop of limited understanding of the dynamic complexity of the financial business environment in the digital age. A case study of a digital financial ecosystem in Zambia within sub-Saharan Africa is then employed herein to reveal the co-evolutionary dynamics of financial inclusion of Generation Z within the framework of complex adaptive systems. For this purpose, a system dynamics modelling tool of Causal loop analysis is used to visualise the co-evolutionary dynamics. The paper has demonstrated that digital financial inclusion occurs within a continuum of co-evolutionary dynamics in which the financial institutions build consumer demand for digital financial services based on the participatory accountability and financial capability of the clientele. The paper concludes that digital financial inclusion is an emergent outcome of the complex adaptive behaviour of a financial business ecosystem in the increasingly digitising society. Therefore, development of inclusive financial business models must embrace the digital consumerism of the clientele, particularly in sub-Saharan Africa where there is a demographic boom of Generation Z with a growing propensity for digital consumerism.

We present an effective reduced-order model (ROM) technique to couple an incompressible flow with a transversely vibrating bluff body in a state-space format. The ROM of the unsteady wake flow is based on the Navier–Stokes equations and is constructed by means of an eigensystem realization algorithm (ERA). We investigate the underlying mechanism of vortex-induced vibration (VIV) of a circular cylinder at low Reynolds number via linear stability analysis. To understand the frequency lock-in mechanism and self-sustained VIV phenomenon, a systematic analysis is performed by examining the eigenvalue trajectories of the ERA-based ROM for a range of reduced oscillation frequency $(F_{s})$, while maintaining fixed values of the Reynolds number ($Re$) and mass ratio ($m^{\ast }$). The effects of the Reynolds number $Re$, the mass ratio $m^{\ast }$ and the rounding of a square cylinder are examined to generalize the proposed ERA-based ROM for the VIV lock-in analysis. The considered cylinder configurations are a basic square with sharp corners, a circle and three intermediate rounded squares, which are created by varying a single rounding parameter. The results show that the two frequency lock-in regimes, the so-called resonance and flutter, only exist when certain conditions are satisfied, and the regimes have a strong dependence on the shape of the bluff body, the Reynolds number and the mass ratio. In addition, the frequency lock-in during VIV of a square cylinder is found to be dominated by the resonance regime, without any coupled-mode flutter at low Reynolds number. To further discern the influence of geometry on the VIV lock-in mechanism, we consider the smooth curve geometry of an ellipse and two sharp corner geometries of forward triangle and diamond-shaped bluff bodies. While the ellipse and diamond geometries exhibit the flutter and mixed resonance–flutter regimes, the forward triangle undergoes only the flutter-induced lock-in for $30\leqslant Re\leqslant 100$ at $m^{\ast }=10$. In the case of the forward triangle configuration, the ERA-based ROM accurately predicts the low-frequency galloping instability. We observe a kink in the amplitude response associated with 1:3 synchronization, whereby the forward triangular body oscillates at a single dominant frequency but the lift force has a frequency component at three times the body oscillation frequency. Finally, we present a stability phase diagram to summarize the VIV lock-in regimes of the five smooth-curve- and sharp-corner-based bluff bodies. These findings attempt to generalize our understanding of the VIV lock-in mechanism for bluff bodies at low Reynolds number. The proposed ERA-based ROM is found to be accurate, efficient and easy to use for the linear stability analysis of VIV, and it can have a profound impact on the development of control strategies for nonlinear vortex shedding and VIV.

A scaled robotic endoscopy platform (REP) was previously developed to efficiently test new control schemes in a simulated colon environment. This article presents the derivation and tuning of a nonlinear model of the REP operating on various substrates. The modeling technique and novel empirical friction profiling demonstrated here are useful for a wide variety of devices interacting with unconventional substrates. The model is first derived from the REP drivetrain inertial characteristics, and then the interaction with synthetic tissue is quantified by an automated traction measurement system for multiple substrates. The resulting model is then used with ground-truth VICON and sensor data to optimize uncertain parameters by minimizing pose error over a variety of tests and substrates. The results show an average error reduction of 67% over all tests and substrates, with a worst-case 10% open-loop final position error. The success of these results proves a robust dynamic model of the REP and its tissue interactions without the need to model complex and computationally expensive viscoelastic material properties or discrete/nonlinear events such as stalling. The resulting model will be used to develop model-based feedback control for estimation, disturbance rejection, and autonomy for the REP in an actuated colon simulator.