Authors: Karimi, Hamid Reza

Abstract: This paper proposes a numerical approach for finding an optimal control based on wavelet functions for vibration reduction of a base-isolated building subjected to actual earthquakes. The objective is two-fold: (1) to find a computational method using properties of Haar functions, and (2) to calculate controller gains approximately by solving only algebraic equations instead of solving the Riccati differential. Simulation results are included to demonstrate the validity and applicability of the technique.

Keywords: Vibration and modal analysis; Control under computation constraints

Identifier: 10.3182/20110828-6-IT-1002.03169

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Nagase, Kenji; Takeuchi, Yasuyuki

Abstract: This paper is concerned with a new feedback control design methodology for vibration control of flexible structures by the wave control. In the wave control, controllers are usually designed to minimize the reflection coefficient based on the wave analysis. However, because the method utilizes the wave analysis directly, it has been mainly applied to simple uniform structures, and the control design method with some additional control objectives has not been established yet. In this paper, aiming to establish a control design method for more complex systems and more complex control design, we propose a method based on the impedance matching index, which represents the difference of the transfer functions between the closed system and the controller. The index is motivated by the wave analysis and control for the uniformly varying ladder networks, an electric circuit analogy of a class of mechanical systems. As a design example for vibration control of mechanical systems, optimal tuning of the passive damper and the dynamic absorber by the index is conducted in the numerical example.

Keywords: Application of mechatronic principles; Identification and control methods

Identifier: 10.3182/20110828-6-IT-1002.00498

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Cazzulani, Gabriele; Ghielmetti, Christian; Resta, Ferruccio; Ripamonti, Francesco

Abstract: In this paper an active modal TMD control logic for the vibration suppression is presented. Starting from the traditional TMD theory, a closed loop formulation is proposed to calculate the active control force. The possibility to describe every mechanical systems or civil structures with a set of modal coordinates allows to act independently on each modal degree of freedom. The technique is compared with different solutions already present in literature, such as the IMSC and the PPF. Numerical simulations, based on a FEM linear model, are carried out to investigate the pro and con of each logic.

Keywords: Linear systems; Observers for linear systems

Identifier: 10.3182/20110828-6-IT-1002.02087

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Aribowo, Wisnu; Yamashita, Takahito; Terashima, Kazuhiko; Masui, Youji; Saeki, Toru; Kamigaki, Toshio; Kawamura, Hirotoshi

Abstract: High speed operation of industrial transfer robot arm generates residual vibration, which in many cases may limit productivity of the factory. In this paper, we use input shaping approach to reduce the residual vibration. The approach needs value of natural frequency and damping ratio to be identified in advance. We present an integrated tool of parameter identification and vibration control for higher modes vibration systems, as an easy and effective tool to help industrial people to analyze and solve the vibration problem. A semiconductor wafer transfer robot arm is used as an application case. Experiments have been carried out, and the results showed big reduction in settling time as well as total movement time of the robot arm.

Keywords: Vibration and modal analysis; Frequency domain identification; Input and excitation design

Identifier: 10.3182/20110828-6-IT-1002.02675

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Zhu, Wen-Hong; Vukovich, George

Abstract: Virtual decomposition control (VDC) is one of the most efficient approaches toward precision control of complex robots. The VDC approach uses subsystem (such as links and joints) dynamics with parametric uncertainty to construct model-based feedforward compensation terms and guarantees the stability of the entire complex robot with mathematical certainty, leading to precise motion/force tracking control with the control bandwidth being independent of the feedback control gains. The VDC approach can be naturally applied to modular robot manipulators to overcome their long-standing problem of lacking control precision in coordinated motion. In this paper, with respect to a typical module comprised of two links and one joint, the control equations of VDC are given and the virtual stability, a necessary and sufficient condition to ensure the stability of the entire robot, is proven. The experiment result yields unprecedented motion tracking precision for a one-module robot using a harmonic drive with significant friction. The ratio of the maximum position tracking error to the maximum velocity reaches 0.00024 (s).

Keywords: Robots manipulators; Robotics technology

Identifier: 10.3182/20110828-6-IT-1002.02233

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Zhou, Zewei; Feng, YiPing; Rong, Gang; Zhu, Feng

Abstract: A virtual factory integrated manufacturing system combined with system simulation and virtual reality is introduced in this paper. We describe the system architecture and development methodology, provide the working principle of process simulation and monitoring in virtual factory, and then explain the detailed applications of virtual factory integrated manufacturing system. With the visualization and three-dimensional human-computer interaction about process and production data, this platform can provide effective supports on monitoring, control and operation of manufacturing system.

Keywords: Intelligent manufacturing systems; Architectures and software tools for enterprise integration and networking in manufacturing; Decision support systems in manufacturing

Identifier: 10.3182/20110828-6-IT-1002.00328

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Formentin, Simone; Savaresi, Sergio

Abstract: In the scientific literature, model-reference control of LPV systems is rarely treated. In data-driven settings where input-output models are derived, further manipulation steps are required between model identification and controller tuning, since all existing design methods rely on state-space representation of the plant dynamics. In this work, a data-driven algorithm is proposed to directly design a model-reference controller without need of identifying and transforming the process. The method is based on the Virtual Reference Feedback Tuning (VRFT) approach and it guarantees very good performance if model-matching can be achieved and the controller is correctly parameterized. A preliminary study of the undermodeling case is proposed to lay the groundwork of future research.

Keywords: Linear parameter-varying systems; Data-based control; Model following control

Identifier: 10.3182/20110828-6-IT-1002.01184

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Gratal, Xavi; Romero, Javier; Kragic, Danica

Abstract: We propose a system for markerless pose estimation and tracking of a robot manipulator. By tracking the manipulator, we can obtain an accurate estimate of its position and orientation necessary in many object grasping and manipulation tasks. Tracking the manipulator allows also for better collision avoidance. The method is based on the notion of virtual visual servoing. We also propose the use of distance transform in the control loop, which makes the performance independent of the feature search window.

Keywords: Robust neural and fuzzy control; Fuzzy and neural systems relevant to control and identification

Identifier: 10.3182/20110828-6-IT-1002.02970

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Winkler, Alexander; Suchý, Jozef

Abstract: This article presents an approach to collision avoidance of industrial robots. It is based on the method of artificial potential or force fields. The field is generated by virtual charges which are placed on obstacles. The virtual force acts on the robot which results in the modification of the manipulator path to avoid collisions. Robot path modification is performed by means of impedance control. The positions of the obstacles are determined continuously by image processing using a simple USB camera, therefore collision avoidance is also able to deal with moving obstacles, e.g. other manipulators. All algorithms are implemented with a real robot system and experimental results are presented.

Keywords: Intelligent robotics; Robots manipulators; Robotics technology

Identifier: 10.3182/20110828-6-IT-1002.00472

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Gomez Balderas, Jose Ernesto; Castillo, Pedro; Guerrero, Jose Alfredo; Lozano, Rogelio

Abstract: A vision based line tracking control strategy for a mini-rotorcraft is presented in this paper. The vision algorithm, employed to estimate the 3D position of the mini helicopter, is based on the vanishing points technique. Also, the dynamic model of this rotorcraft is presented in order to propose a nonlinear controller to navigate following a line. To validate the theoretical results, a real-time embedded control system has been developed. Experimental results have shown the good behavior of the proposed control vision scheme.

Keywords: Flying robots; Autonomous robotic systems; Guidance navigation and control

Identifier: 10.3182/20110828-6-IT-1002.03489

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Takahashi, Satoru

Abstract: In this paper, we introduce a tracking method for moving insect. Our method is robust image processing to change of illumination under orientation code matching. Further, based on an extended Kalman filter, it can track moving insects which are acting under the random motion. Through experiments, this paper shows effectiveness of our method.

Keywords: Tracer kinetic modeling using various imaging systems; Biomedical imaging systems; Parameter and state estimation

Identifier: 10.3182/20110828-6-IT-1002.02664

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Yamamoto, Shigeru; Sakaguchi, Eiji

Abstract: In this paper, we consider a decentralized control problem for suppressing the traffic jam in a cyclic traffic flow. In recent years, to explain the mechanism that causes the traffic jam, experiments have been done for multiple vehicles on the circle. The traffic jam can be explained by the so-called optimal velocity model with the model, the optimal velocity function which is a nonlinear function of the headway of the preceding vehicle and describes driver's characteristics. In this paper, we apply washout control to suppress the traffic jam in a cyclic traffic flow not to disturb driver's characteristics. Then, we show a method to select parameters to keep stability of the closed-loop system. We find that our proposed method for selecting parameters is better than the conservative method using the small gain theorem. In addition, we illustrate the effectiveness with several simulations.

Keywords: Intelligent driver aids; Integrated traffic management; Man-machine interfaces

Identifier: 10.3182/20110828-6-IT-1002.02388

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Arce, Alicia; Bordons, Carlos; Del Real, Alejandro J.

Abstract: This paper presents a controllability study of the water management inside the anode channel by regulating the stack temperature for PEM fuel cell systems with dead-ended anode. Moreover, this work includes the design of a steady-state target optimizer which calculates the temperature set-point profiles that minimize the stack degradation and the hydrogen leaks. The control architecture is successfully simulated and the results show promising performance.

Keywords: Optimal operation and control of power systems; Control system design; Model predictive and optimization-based control

Identifier: 10.3182/20110828-6-IT-1002.02432

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Aalto, Atte Erkko Juhani; Malinen, Jarmo

Abstract: We consider dynamical systems defined on graph structures. The dynamics on the edges are governed by partial differential equations that are interconnected at the graph vertices through algebraic conditions involving the boundary conditions of the PDEs. We show that a variety of such wave propagation problems on networks are solvable (forward in time) and energy passive or conservative — given that the governing PDEs are solvable on the separate edges. We treat these problems in the operator theoretic boundary control system framework.

Keywords: Input and excitation design; Vibration and modal analysis

Identifier: 10.3182/20110828-6-IT-1002.01439

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Osinuga, Mobolaji; Patra, Sourav; Lanzon, Alexander

Abstract: This paper proposes a design framework that maximizes the robust performance of a closed-loop system via weight optimization in H_infinity loop-shaping control. In line with design objectives, frequency-dependent optimization problems are formulated in LMI framework to maximize robust performance at low and high frequencies, and directly improve the robust stability margin at mid frequencies. The philosophy of the work thus gives the best robust performance that can be achieved on a particular problem once a level of robust stability margin is demanded. Loop-shaping weights and controller are simultaneously synthesized from the proposed algorithm.

Keywords: Robust control (linear case); LMIs; Convex optimization

Identifier: 10.3182/20110828-6-IT-1002.00153

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Wei, Peng; Sun, Dengfeng

Abstract: The airport transportation network structure and its performance are key factors to benefit the local area or national transportation capability and economic development. This paper presents a method based on the weighted algebraic connectivity to optimize and analyze the network. The indispensability of the weighted adjacent matrix and weighted Laplacian matrix in airport transportation network performance study is emphasized in this paper. According to practical operational viability, we formulate the weighted algebraic connectivity application as the flight routes addition/deletion problems. The greedy perturbation heuristic by Ghosh and Boyd is analyzed and extended into the Modified Greedy Perturbation Algorithm (MGP) to provide a local optimum in a fast iterative manner. The unweighted tabu search applying algebraic connectivity to airport transportation network by Vargo and Kincaid is re-designed as the Weighted Tabu Search (WTS) to fit the new weighted flight routes addition/deletion problems, potentially offering a global optimum with much longer running time. The simulation results indicate the trade-off between the Modified Greedy Perturbation and the Weighted Tabu Search, with which we can decide the appropriate algorithm to be used for enhancing the performance of an airport transportation network.

Keywords: Modeling and simulation of transportation systems; Automatic control, optimization, real-time operations in transportation

Identifier: 10.3182/20110828-6-IT-1002.00486

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Beattie, Christopher A.; Gugercin, Serkan

Abstract: Weighted model reduction problems appear in many important applications such as controller reduction. The most common approach to this problem is the weighted balanced truncation method. Interpolatory approaches to weighted model reduction have been mostly limited to simply choosing interpolation points in the regions where the weights are dominant. In this paper, we extend the (unweighted) tangential interpolatory model reduction to the weighted case using the recent generalized interpolation framework of cite{beattie2009ipm}. We generate a reduced-order model such that the weighted reduced-order system tangentially interpolates the weighted full-order system at the provided interpolation data.

Keywords: Linear systems; Large scale optimization problems

Identifier: 10.3182/20110828-6-IT-1002.03419

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Kong, Fook; Kuhn, Daniel; Rustem, Berc

Abstract: The set of correlated equilibria is convex and contains all Nash equilibria as special cases. Thus, the social welfare-maximizing correlated equilibrium is amenable to convex analysis and offers social welfare that is at least as good as the game’s best performing Nash equilibria.We employ robust semidefinite programming (SDP) for computing the social welfare-maximizing correlated equilibria in static polynomial games, giving rise to a dedicated sequential SDP algorithm, the first of this type that can cope with multivariate strategy sets. We apply this algorithm to a wireless communication problem, where two mutually-interfering transmitters and receivers maximize their channel capacities.

Keywords: Control over communication; Control of networks; Multi-agent systems

Identifier: 10.3182/20110828-6-IT-1002.02982

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Spudić, Vedrana; Baotic, Mato; Perić, Nedjeljko

Abstract: We propose an optimization-based strategy for wind farm control. The objectives for the farm are to produce demanded power and to minimize the loads on mechanical parts of wind turbines that occur due to turbulent winds. The load reduction is achieved by dynamic adaptation of individual wind turbine power references to the current, turbulence induced, disturbances. However, the changes in operation of all wind turbines are coordinated to ensure that the wind farm produces power according to the grid operator demands. The pursued approach uses parametric programming to find the optimal control actions for the wind farm with respect to the constraints inherent to the system. The considered control design is also motivated by the need for efficient controller computation that will allow implementations on large wind farms.

Keywords: Optimal operation and control of power systems; Control system design

Identifier: 10.3182/20110828-6-IT-1002.02956

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Ozdemir, Ahmet Arda; Seiler, Peter; Balas, Gary J.

Abstract: Up-down counters are commonly used in the aerospace industry for fault detection thresholding. This paper applies the up-down counter technique to detect wind turbine faults. The thresholding problem involves a tradeoff between false alarms and missed detections. Counter based thresholding can detect smaller faults with higher probability and lower false alarms than is possible using simple constant thresholds. This improvement is achieved by effectively introducing dynamics into the thresholding logic as opposed to decisioning based on a single time step. Up down counters are applied to the development of a fault detection system for a commercial sized 4.8MW wind turbine. Realistic fault scenarios in the sensing, actuation and drivetrain subsystems are considered. It is seen that most faults can be detected with fast detection times and minimal false alarms without implementation of more complex filtering and detection techniques on residuals.

Keywords: Fault detection and diagnosis; Continuous time system estimation; Estimation and filtering

Identifier: 10.3182/20110828-6-IT-1002.01758

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Cai, Shichao; Becherif, Mohamed; Wack, Maxime

Abstract: Components and actuators of modern vehicles are now tested using a Laptop in a repairing garage. In the near future, those tests will be done using a wireless communication. This paper deals with the wireless control of a car actuator. In order to control the angular displacement of an automobile Pierburg mechatronic actuator and achieve a wireless network control, a new PID-fuzzy logic controller topology is designed, which takes advantage of PID and fuzzy logic controllers and reduce the time delay caused by the wireless communication in the control loop. Different from other fuzzy PID controllers, our PID controller is located before the fuzzy controller and acts as its inputs. The proposed PID-fuzzy logic controller achieves the control task reducing the steady-state error. Experimentation of the wireless control is presented exhibiting good results.

Keywords: Nonlinear system control; Systems with time-delays; Adaptive control

Identifier: 10.3182/20110828-6-IT-1002.03067

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Lieu, Binh K.; Jovanovic, Mihailo; Kumar, Satish

Abstract: Amplification of deterministic disturbances in inertialess channel flows of viscoelastic fluids is studied by analyzing the frequency responses from spatio-temporal body forces to the velocity fluctuations. In strongly elastic flows, we show that velocity fluctuations can exhibit significant amplification even in the absence of inertia. Our analysis demonstrates that streamwise-constant disturbances are the most amplified. Explicit expressions are established for the worst-case amplification of velocity fluctuations arising from different components of the body forces. These show that amplification from the wall-normal and spanwise forces to the streamwise velocity component scales quadratically with the Weissenberg number. The underlying physical mechanism involves stretching of polymer stress fluctuations by a background shear, which is a close analog of the vortex titling mechanism that is responsible for amplification in inertial flows of Newtonian fluids.

Keywords: Infinite-dimensional systems; Robustness analysis; Complex systems

Identifier: 10.3182/20110828-6-IT-1002.03289

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011

Authors: Stoican, Florin; Olaru, Sorin; De Dona, Jose Adrian; Seron, Maria

Abstract: This paper deals with robust invariant sets construction for discrete-time linear time-invariant dynamics. The case of a zonotopic disturbance set is analysed in detail by exploiting the properties of these geometrical structures. A constructive method is provided for diminishing the conservatism of ultimate bound invariant sets. It is shown that the resulting zonotopic set is related to the minimal robust positively invariant set in the sense that their boundaries have common points. %Finally, it is shown that the geometrical construction is equivalent to a low complexity optimisation problem.

Keywords: Convex optimization; Linear systems

Identifier: 10.3182/20110828-6-IT-1002.03247

Conference: Proceedings of the 18th IFAC World Congress, 2011

Location: Università Cattolica del Sacro Cuore, Milano, Italy

Start Date: Sun Aug 28 2011 - End Date: Fri Sep 02 2011