Dominik Pisarski, Ph.D. 

Doctoral thesis
20120426  SemiActive Control System for Trajectory Optimization of a Moving Load on an Elastic Continuum
 656 
20140916  Collaborative Ramp Metering Control: Application to Grenoble South Ring (Université Grenoble)
 1079 
Recent publications
1.  Pisarski D., Decentralized stabilization of semiactive vibrating structures, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 08883270, DOI: 10.1016/j.ymssp.2017.08.003, Vol.100, pp.694705, 2018 Abstract: A novel method of decentralized structural vibration control is presented. The control is assumed to be realized by a semiactive device. The objective is to stabilize a vibrating system with the optimal rates of decrease of the energy. The controller relies on an easily implemented decentralized switched statefeedback control law. It uses a set of communication channels to exchange the state information between the neighboring subcontrollers. The performance of the designed method is validated by means of numerical experiments performed for a double cantilever system equipped with a set of elastomers with controlled viscoelastic properties. In terms of the assumed objectives, the proposed control strategy significantly outperforms the passive damping cases and is competitive with a standard centralized control. The presented methodology can be applied to a class of bilinear control systems concerned with smart structural elements. Keywords:structural control, decentralized control, smart structures, modular structures, stabilization Affiliations:
 
2.  Pisarski D., Konowrocki R., Szmidt T., Dynamics and optimal control of an electromagnetically actuated cantilever pipe conveying fluid, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022460X, DOI: 10.1016/j.jsv.2018.06.045, Vol.432, pp.420436, 2018 Abstract: This paper deals with the problem of applying electromagnetic devices of the motional type to improve the dynamic stability of a pipe conveying air. When the flow velocity reaches a critical value, the steady equilibrium position becomes unstable, and selfexcited lateral vibrations arise. In contrast, electromagnetic devices of the transformer type have been demonstrated to be highly effective in the passive stabilization of such a system, as well as the active stabilization of similar nonconservative systems with a follower force. In the present paper, we apply a pair of motional devices made of a conducting plate which is attached to the pipe and moves together with it within the perpendicular magnetic field generated by the controlled electromagnets. This motion generates eddy currents in the plates and a drag force of a viscous character. In this setting, we first investigate the possibility of designing a stabilizing control within the region of the magnetic field where every passive solution results in an fluid–structure interaction, electromagnetic device, optimal control, stabilization, smart structure Affiliations:
 
3.  Pisarski D., Optimal control of structures subjected to traveling load, JOURNAL OF VIBRATION AND CONTROL, ISSN: 10775463, DOI: 10.1177/1077546316657244, Vol.24, No.7, pp.1283 1299, 2018 Abstract: The problem of the optimal semiactive control of a structure subjected to a moving load is studied. The control is realized by a change of damping of the structure’s supports. The objective is to provide a smooth passage for vehicles and extend the time needed for the safety service of the carrying structures. In contrast to the previous works of the author, in this paper, the model used takes into account timevarying passage speeds, which allows a broader application, in particular, to robotics. The study of the optimal control problem produces a practical condition that justifies whether, for a given set of parameters, the controlled system can outperform its passively damped equivalent. For the optimization, an efficient method of parametrized switching times is developed and tested via a numerical example. The designed optimal control is examined on a real test stand. The experiments are carried out for three different passage scenarios. In terms of the assumed metrics the proposed method outperforms the passive case by over 40%. Keywords:optimal control, structural control, semiactive control, vibration control, moving load Affiliations:
 
4.  Bajer C.I., Pisarski D., Szmidt T., Dyniewicz B., Intelligent damping layer under a plate subjected to a pair of masses moving in opposite directions, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022460X, DOI: 10.1016/j.jsv.2017.01.046, Vol.394, pp.333347, 2017 Abstract: Reducing displacements of a plate vibrating under a pair of masses traveling in opposite directions can be improved by adding a smart subsoil instead of a classical damping layer. We propose a material that acts according to the instantaneous state of the plate, i.e., its displacements and velocity. Such an intelligent damping layer reduces vertical displacements even by 40%–60%, depending on the type of load and the assumed objective function. Existing materials enable the application of the proposed layer in a semiactive mode. The passive mode can be applied with materials exhibiting directiondependent viscosity. Keywords:Plate vibration, Moving load, Intelligent damping layer, Semiactive damping Affiliations:
 
5.  Szmidt T., Pisarski D., Bajer C.I., Dyniewicz B., Doublebeam cantilever structure with embedded intelligent damping block: Dynamics and control, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022460X, DOI: 10.1016/j.jsv.2017.04.033, Vol.401, pp.127138, 2017 Abstract: In this paper, a semiactive method to control the vibrations of twin beams connected at their tips by a smart damping element is investigated. The damping element can be made of a magnetorheological elastomer or a smart material of another type, for instance, vacuum packed particles. What is crucial is the ability to modify the storage and loss moduli of the damping block by means of devices attached directly to the vibrating structure. First, a simple dynamical model of the system is proposed. The continuous model is discretized using the Galerkin procedure. Then, a practical statefeedback control law is developed. The control strategy aims at achieving the best instantaneous energy dissipation of the system. Numerical simulations confirm its effectiveness in reducing free vibrations. The proposed control strategy appears to be robust in the sense that its application does not require any knowledge of the initial conditions imposed on the structure, and its performance is better than passive solutions, especially for the system induced in the first mode. Keywords:Vibration control, Doublebeam structure, Sandwich beam, Magnetorheological elastomer, Semiactive damping, Stabilization Affiliations:
 
6.  Dyniewicz B., Pisarski D., Bajer C.I., Vibrations of a Mindlin plate subjected to a pair of inertial loads moving in opposite directions, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022460X, DOI: 10.1016/j.jsv.2016.09.027, Vol.386, pp.265282, 2017 Abstract: A Mindlin plate subjected to a pair of inertial loads traveling at a constant high speed in opposite directions along arbitrary trajectory, straight or curved, is presented. The masses represent vehicles passing a bridge or track plates. A numerical solution is obtained using the space–time finite element method, since it allows a clear and simple derivation of the characteristic matrices of the timestepping procedure. The transition from one spatial finite element to another must be energetically consistent. In the case of the moving inertial load the classical timeintegration schemes are methodologically difficult, since we consider the Dirac delta term with a moving argument. The proposed numerical approach provides the correct definition of force equilibrium in the time interval. The given approach closes the problem of the numerical analysis of vibration of a structure subjected to inertial loads moving arbitrarily with acceleration. The results obtained for a massless and an inertial load traveling over a Mindlin plate at various speeds are compared with benchmark results obtained for a Kirchhoff plate. The pair of inertial forces traveling in opposite directions causes displacements and stresses more than twice as large as their corresponding quantities observed for the passage of a single mass. Keywords:Mindlin plate, Mass moving at varying speed, Arbitrary trajectory, Inertial load, Space–time finite element method Affiliations:
 
7.  Pisarski D., Myśliński A.^{♦}, Online adaptive algorithm for optimal control of structures subjected to travelling loads, OPTIMAL CONTROL APPLICATIONS & METHODS, ISSN: 01432087, DOI: 10.1002/oca.2321, Vol.38, No.6, pp.11681186, 2017 Abstract: The problem of adaptive optimal semiactive control of a structure subjected to a moving load is studied. The control is realised by a change of damping of the structure’s supports. The results presented in the previous works of the authors demonstrate that switched optimal controls can be very efficient at reducing the vibration levels of the structure. On the other hand, these controls exhibit a high sensitivity to changes of the speed of the travelling load. The aim of this paper is to develop an algorithm that enables realtime adaptation of the optimal controls according to both the measured speed of the travelling load and the estimated state of the structure. The control objective is to provide smooth passage for the vehicles and reduce the material stresses on the carrying structures. The designed adaptive algorithm uses reference optimal controls computed for constant speeds and a set of functions describing the sensitivity of the system dynamics to the measured parameters. The convergence of the algorithm, as well as aspects of its implementation, is studied. The performance of the proposed method is validated by means of numerical simulations conducted for different travelling speed scenarios. In the assumed objective functional, the proposed adaptive controller can outperform the reference optimal solutions by over 50%. The practicality of the proposed method should attract the attention of practising engineers. Keywords:Adaptive control, Moving load, Online optimal control, Sensitivity analysis, Structural vibration control Affiliations:
 
8.  Pisarski D., Bajer C.I., Dyniewicz B., Bajkowski J.M.^{♦}, Vibration control in smart coupled beams subjected to pulse excitations, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022460X, DOI: 10.1016/j.jsv.2016.05.050, Vol.380, pp.3750, 2016 Abstract: In this paper, a control method to stabilize the vibration of adjacent structures is presented. The control is realized by changes of the stiffness parameters of the structure׳s couplers. A pulse excitation applied to the coupled adjacent beams is imposed as the kinematic excitation. For such a representation, the designed control law provides the best rate of energy dissipation. By means of a stability analysis, the performance in different structural settings is studied. The efficiency of the proposed strategy is examined via numerical simulations. In terms of the assumed energy metric, the controlled structure outperforms its passively damped equivalent by over 50 percent. The functionality of the proposed control strategy should attract the attention of practising engineers who seek solutions to upgrade existing damping systems. Keywords:vibration, damping, smart materials, control, semiactive Affiliations:
 
9.  Bajkowski J.M.^{♦}, Bajer C.I., Dyniewicz B., Pisarski D., Vibration control of adjacent beams with pneumatic granular coupler: an experimental study, Mechanics Research Communications, ISSN: 00936413, DOI: 10.1016/j.mechrescom.2016.10.005, Vol.78, pp.5156, 2016 Abstract: A novel type of pneumatic device filled with granular material is proposed in the implementation of a switched control strategy to stabilize the vibration of slender structures. The analytically obtained control law for the airtight, elastic, granular coupler is implemented in a test structure with a relaytype control logic. In the experiment, the deformable granular coupler semiactively damps an initially deflected pair of adjacent, aluminum beams. Two cases of initial excitation are considered, showing an improvement of up to 33 percent in vibration abatement efficiency compared to the passive case. Although this semiactive device is conceptually simple, its ease of operation and low cost should attract the attention of engineers who seek solutions that can be used to build new structures and upgrade existing ones. Affiliations:
 
10.  Pisarski D., Szmidt T., Bajer C.I., Dyniewicz B., Bajkowski J.M.^{♦}, Vibration Control of DoubleBeam System with Multiple Smart Damping Members, SHOCK AND VIBRATION, ISSN: 10709622, DOI: 10.1155/2016/2438902, Vol.2016, pp.2438902114, 2016 Abstract: A control method to stabilize vibration of a double cantilever system with a set of smart damping blocks is designed and numerically evaluated. The externally controlled magnetorheological sheared elastomer damping block is considered, but other smart materials can be used as well. The robust bangbang control law for stabilization the bilinear system is elaborated. The key feature of the closed loop controller is the efficiency for different types of initial excitement. By employing the finite element model, the performance of the controller is validated for strong wind blow load and concentrated impact excitement of the particular point of one of the beams. For each of the excitations, the closed loop control outperforms the optimal passive damping case by over 27% for the considered energy metric. Affiliations:
 
11.  Wasilewski M., Pisarski D., Bajer C.I., Adaptive stabilization of partially damaged vibrating structures, Machine Dynamics Research, ISSN: 20809948, Vol.40, No.1, pp.6582, 2016 Abstract: In this paper, an online adaptive continuoustime control algorithm will be studied in the vibration control problem. The examined algorithm is a Reinforcement Learning based scheme able to adapt to the changing system’s dynamics and providing control converging to the optimal control. Firstly, a brief description of the algorithm is provided. Then, the algorithm is studied by the numeric simulation. The controlled model is a simple conjugate oscillator with a sudden change of its rigidity. The effectiveness of the adaptation of the algorithm is compared to the simulation results of controlling the same object by the traditional Linear Quadratic Regulator. Because of the lack of constraints for a system size or its linearity, this algorithm is suitable for optimal stabilization of more complex vibrating structures. Keywords:Vibration control, Adaptive control, Optimal control, Policy iterations, HamiltonJacobiBellman equation Affiliations:
 
12.  Pisarski D.^{♦}, CanudasdeWit C.^{♦}, Nash Game Based Distributed Control Design for Balancing of Traffic Density over Freeway Networks, IEEE Transactions on Control of Network Systems, ISSN: 23255870, DOI: 10.1109/TCNS.2015.2428332, Vol.3, No.2, pp.149161, 2016 Abstract: In this paper, we study the problem of optimal balancing of vehicle density in freeway traffic. The optimization is performed in a distributed manner by utilizing the controllability properties of the freeway network represented by the Cell Transmission Model. By using these properties, we identify the subsystems to be controlled by local ramp meters. The optimization problem is then formulated as a noncooperative Nash game that is solved by decomposing it into a set of twoplayers hierarchical and competitive games. The process of optimization employs the communication channels matching the switching structure of system interconnectivity. By defining the internal model for the boundary flows, local optimal control problems are efficiently solved by utilizing the method of linear quadratic regulator. The developed control strategy is tested via numerical simulations in two scenarios for uniformly congested and transient traffic. Affiliations:
 
13.  Pisarski D., Distributed Control Design for Structures Subjected to Traveling Loads, MATHEMATICAL PROBLEMS IN ENGINEERING, ISSN: 1024123X, DOI: 10.1155/2015/206870, Vol.2015, pp.206870112, 2015 Abstract: This paper presents a novel distributed control method that adapts the structures subjected to traveling loads. The adaptation is realized by changes of the damping of the structure’s supports. The control objective is to provide smooth passage of vehicles and to extend the safe lifetime of the carrying structures. The results presented in the previous works of the author exhibited high performance of supports with an openloop switching damping policy. In this paper, the goal is to develop a state feedback strategy that is significantly less sensitive to the system parameters and much simpler for practical implementation. Further efforts are put into designing a distributed controller architecture, where only the local and the relevant neighboring states are used to compute the control decisions. The proposed controller is validated experimentally. It exhibits high performance in a wide range of travel speeds. The practicality of the proposed solution should attract the attention of practicing engineers. Affiliations:
 
14.  Dyniewicz B., Pisarski D., Konowrocki R., Semiactive control of track subjected to an inertial moving load, VIBRATIONS IN PHYSICAL SYSTEMS, ISSN: 08606897, Vol.25, pp.147152, 2012 Abstract: The paper deals with the problem of stabilization of vibrations of the load carrying structure via adaptive damping performed with a smart material. The properties of such a material must ensure reduction of vibrations, especially accelerations and displacements of selected stationary or follower points in a higher range than in the case of the material with homogeneous bilateral characteristics. Analytical calculations and numerical simulations proved the eﬃciency of the approach. Results obtained with the testing system equipped with magnetorheological controlled dampers will allow us to prove experimentally assumed control strategies and rheological properties of the ﬁlling material. Keywords:control, moving inertial load, vibrations, smart materials Affiliations:
 
15.  Pisarski D., Bajer C.I., Smart suspension system for linear guideways, JOURNAL OF INTELLIGENT AND ROBOTIC SYSTEMS, ISSN: 09210296, DOI: 10.1007/s1084601094507, Vol.62, pp.451466, 2011 Abstract: This paper presents a new method for the semiactive control of the span system of linear guideways subjected to a travelling load. Two elastic beams are coupled by a set of controlled dampers. The relative velocity of the spans provides an opportunity for efficient control via semiactive suspension. The magnitude of the moving force is assumed to be constant by neglecting inertial forces. The response of the system is solved in modal space. The full analytical solution is based on the power series method and can be given over an arbitrary time interval. The control strategy is formulated by using bilinear optimal control theory. As a result, bangbang controls are taken into account. The final solution is obtained as a numerical mean value. Several examples demonstrate the efficiency of the proposed method. The controlled system outperforms passive solutions over a wide range. Due to the simplicity of its design, the presented solution should be interesting to engineers. Keywords:Semiactive control, Smart suspension system, Vibration control, Linear guideway, Moving load Affiliations:
 
16.  Pisarski D., Bajer C.I., Semiactive control of 1D continuum vibrations under a travelling load, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022460X, DOI: 10.1016/j.jsv.2009.09.006, Vol.329, pp.140149, 2010 Abstract: The paper presents a method for computing the response of a 1D elastic continuum supported by a set of semiactive viscous dampers and induced by a load travelling over it. The magnitude of the moving force has been assumed to be constant by neglect of the inertia forces. Full analytical solution is based on the power series method and is given in an arbitrary time interval. The timemarching scheme allows us to continue a solution in successive layers with initial conditions taken from the end of previous stages. The semiactive open loop control strategy is proposed. Shapes of damping functions are defined as a form of piecewise constant function. The control strategy is suboptimal and it outperforms the passive case. Numerical results are presented for the cases of a string and a Bernoulli–Euler beam. Affiliations:
 
17.  Pisarski D., Bajer C.I., On the semiactive control of carrying structures under moving a load, VIBRATIONS IN PHYSICAL SYSTEMS, ISSN: 08606897, Vol.24, pp.325330, 2010 Abstract: In this paper we address a group of recent research focused on the semi active control problems in carrying structures systems subjected to a travelling load. The magnitude of the moving force is assumed to be constant by neglecting inertial forces. The response of the system is solved in modal space. The optimal control problem is stated and it is solved by using of Pontryagin Maximum Principle. Switching control method is verified by numerical examples. The controlled system widely outperforms passive solutions. Due to its simplicity in practical design, the presented solution should be interesting to engineers. Keywords:Semiactive control, structural control, optimization, moving load Affiliations:
 
18.  Pisarski D., Bajer C.I., Aktywne tłumienie drgań struny i belki pod obciążeniem ruchomym, DROGI I MOSTY, ISSN: 16431618, Vol.8, No.4, pp.7187, 2009 
List of recent monographs
1. 372  Bajer C.I., Dyniewicz B., Pisarski D., Bajkowski J.M.^{♦}, Vibration control with smart materials, IPPT PAN, pp.1240, 2015 
List of chapters in recent monographs
1. 300  Bajer C.I., Myśliński A.^{♦}, Żochowski A.^{♦}, Dyniewicz B., Pisarski D., Interactive computer environment for solving optimal problemsIDOS, rozdział: Solving optimal control problems described by PDEs, Ed. R. Pytlak, pp.347394, 2012 
2. 486  Pisarski D., Bajer C.I., Theoretical Foundations of Civil Engineering: XVII PolishUkraïnianLithuanian Transactions, rozdział: Active Suspension Control of 1D Continuum under a Travelling Load, Oficyna Wydawnicza Politechniki Warszawskiej, red. nauk.: Wacław Szcześniak, Artur Zbiciak, pp.273278, 2009 
Conference papers
1.  Pisarski D., Myśliński A.^{♦}, Online adaptive semiactive vibration damping of slender structures subject to moving loads, ICoEV 2017, International Conference on Engineering Vibration, 20170904/0907, Sofia (BG), DOI: 10.1051/matecconf/201814805006 , No.148, pp.16, 2018 Abstract: The paper deals with the adaptive optimal semiactive control of the slender vibrating structures subjected to the moving loads. The deflection of the structure is governed by EulerBernoulli beam equation approximated by the system of bilinear ordinary differential equations. The damping function of the structure support is chosen as the control function. The optimal control problem consists in finding such bangbang control function to minimize the energy as well as the vibrations of the carrying structure. Although the switched optimal control is a very efficient tool in the reduction of structure vibrations it is very sensitive with respect to changes of the speed of the traveling load. This paper deals with the development of the adaptive descent type algorithm that enables the update of the optimal controls in real time based on the measured speed of the traveling load or structure’s state. The proposed algorithm uses reference optimal controls computed for the constant speeds and the set of functions describing the sensitivity of the system dynamics with respect to the measured parameters. Numerical computations are carried out for different speed scenarios of the moving load. The obtained numerical results indicate that the proposed adaptive controller can significantly outperform the reference optimal solutions. Affiliations:
 
2.  Pisarski D., On optimal distributed semiactive control of vibrating structures, WCSCM, 7th World Conference on Structural Control and Monitoring, 20180723/0726, Qingdao (CN), pp.31483149, 2018 Abstract: A novel semiactive control method for mitigation of structural vibration is studied. The
 
3.  Wasilewski M., Pisarski D., Adaptive optimal control algorithm for vibrational systems under nonlinear friction, MMAR 2017, 22nd International Conference on Methods and Models in Automation and Robotics, 20170828/0831, Międzyzdroje (PL), pp.107112, 2017 Abstract: In this paper, a novel control algorithm for vibration attenuation is presented. The proposed scheme is developed to control linear systems with a presence of an external disturbance. The goal of the control is to steer the system to prescribed reference trajectory by minimizing associated quadratic performance index.
 
4.  Pisarski D., Collaborative Control for Structures Subjected to Traveling Loads, MSC 2015, IEEE MultiConference on Systems and Control, 20150921/0923, Sydney (AU), DOI: 10.1109/CCA.2015.7320688, pp.557562, 2015 Abstract: The paper presents a novel collaborative control method that adapts the structures subjected to traveling loads. The adaptation is realized by changes of the damping of the structure's supports. The control objective is to provide smooth passage of vehicles and to extend the safe lifetime of the carrying structures. The control method utilizes a distributed architecture where the local controllers communicate along the circular graph. The proposed controller is validated experimentally. It is simple for practical realization and exhibits the performance comparable to that provided by the optimal centralized strategies presented in [1] and [2]. Affiliations:
 
5.  Pisarski D.^{♦}, CanudasdeWit C.^{♦}, Optimal balancing of freeway traffic density: Application to the Grenoble South Ring, ECC 2013, 12th biannual European Control Conference, 20130717/0719, Zurich (CH), pp.40214026, 2013 Abstract: This paper presents the application of the idea of optimal balancing of traffic density distribution. The idea was previously studied in the papers [1], [2], and here it is implemented to the Grenoble South Ring in the context of the Grenoble Traffic Lab. The traffic on the ring is represented by the Cell Transmission Model that was tuned by using real data and Aimsun microsimulator. A special attention is paid to the calibration of a flow merging model. A largescale optimization problem is solved by using decomposition methods and it is implemented by introducing combinatorial procedures. The main difficulties in the implementation as well as the limitations of the designed software are highlighted. Finally, the results of different traffic scenarios on the Grenoble South Ring are presented. Affiliations:
 
6.  Pisarski D.^{♦}, CanudasdeWit C.^{♦}, Analysis and Design of Equilibrium Points for the CellTransmission Traffic Model, ACC, American Control Conference, 20120627/0629, Montréal (CA), DOI: 10.1109/ACC.2012.6315050, pp.57635768, 2012 Abstract: The problem of equilibrium points for the Cell Transmission Model is studied. The structure of equilibrium sets is analyzed in terms of model parameters and boundary conditions. The goal is to determine constant input flows, so that the resultant steady state of vehicle density is uniformly distributed along a freeway. The necessary and sufficient conditions for the existence of onetoone relation between input flow and density are derived. The equilibrium sets are described by formulas that allow to design a desired balanced density. A numerical example for the case of a twocell system is presented. Keywords:Traffic control, Vectors, Vehicles, Equations, Boundary conditions, Steadystate Affiliations:
 
7.  Pisarski D.^{♦}, CanudasdeWit C.^{♦}, Optimal Balancing of Road Traffic Density Distributions for the Cell Transmission Model, CDC, 51st IEEE Annual Conference on Decision and Control, 20121210/1213, Maui (US), DOI: 10.1109/CDC.2012.6426749, pp.69696974, 2012 Abstract: In this paper, we study the problem of optimal balancing of traffic density distributions. The optimization is carried out over the sets of equilibrium points for the Cell Transmission Traffic Model. The goal is to find the optimal balanced density distribution that maximizes the Total Travel Distance. The optimization is executed in two steps. At the first step, we consider a nonlinear problem to find a uniform density distribution that maximizes the Total Travel Distance. The second step is to solve the constrained quadratic problem to find the near balanced optimal equilibrium point. At both steps, we use decomposition methods. The quadratic optimization problem is solved by using the Dual Problem. The computational algorithms associated to such a problem are given. Keywords:Traffic control, Optimization, Vectors, Vehicles, Equations, Boundary conditions Affiliations:
 
8.  Dyniewicz B., Pisarski D., Konowrocki R., Semiactive control of track subjected to an inertial moving load, XXV Symposium Vibrations in Physical Systems, 20120515/0519, PoznańBędlewo (PL), pp.16, 2012 Abstract: The paper deals with the problem of stabilization of vibrations of the load carrying structure via adaptive damping performed with a smart material. The properties of such a material must ensure reduction of vibrations, especially accelerations and displacements of selected stationary or follower points in a higher range than in the case of the material with homogeneous bilateral characteristics. Analytical calculations and numerical simulations proved the eﬃciency of the approach. Results obtained with the testing system equipped with magnetorheological controlled dampers will allow us to prove experimentally assumed control strategies and rheological properties of the ﬁlling material. Keywords:control, moving inertial load, vibrations, smart materials Affiliations:
 
9.  Pisarski D., Bajer C.I., Active Suspension Control of 1D Continuum under a Travelling Load, Theoretical foundations of civil engineering : 17 PolishUkraïnianLithuanian transactions, 200909/09, Warszawa (PL), Vol.17, pp.273278, 2009 
Conference abstracts
1.  Wasilewski M., Pisarski D., Konowrocki R., Bajer C.I., New efficient adaptive control of torsional vibrations induced by sudden nonlinear disturbances, CMM2017, 22nd International Conference on Computer Methods in Mechanics, 20170913/0916, Lublin (PL), pp.12, 2017 Abstract: The aim of this paper is to present a novel adaptive technique of control of the vibrating drilling systems. The algorithm constitutes an adaptive linear quadratic regulator that uses direct measurements of the disturbance to synthesize its linear dynamic approximation. This approach allows generating control law that includes the impact of the friction on the system dynamics and optimally steers the system to the desired trajectory. The effectiveness of the algorithm is validated via comprehensive numerical simulations of the control of the simplified drilling model. The results are compared to these obtained with the use of the Linear Quadratic Gaussian regulator. Keywords:vibration control, drillstring, adaptive control, autoregressive model Affiliations:
 
2.  Pisarski D., Szmidt T., SemiActive Stabilization of Pipe Discharging Air With Electromagnetic Devices of Motional Type, ICAST2017, The 28th International Conference on Adaptive Structures and Technologies, 20171008/1011, Kraków (PL), pp.1, 2017 Abstract: The study deals with a problem of applying electromagnetic devices of motional type to improve the dynamic stability of a pipe conveying air. When the flow velocity reaches its critical value the steady equilibrium position becomes unstable, and selfexcited lateral vibrations arise. Electromagnetic devices of another – transformer – type demonstrated to have been highly effective in the passive stabilization of such system as well as active stabilization of similar nonconservative system with a follower force. In the present work, we apply a pair of motional devices made of a conducting plate which is attached to the pipe and moves together with it within the perpendicular magnetic field generated by the controlled electromagnets. This motion generates eddy currents in the plates and a drag force of a viscous character. Under this setting, we firstly investigate the possibility of designing a stabilizing control within the magnetic field’s region where every passive solution results in an unstable or conservative state. For that purpose, we constitute a practical condition justifying the existence of a stabilizing control for a given set of system parameters. Later we pose and solve an optimal control problem aiming at stabilizing the system with the optimal rates of decrease of the system’s energy. The solution is examined by means of numerical simulations performed within the three regions of the flow velocity: low subcritical where the Coriolis acceleration of the conveyed fluid generates the predominate damping force, high subcritical where the inertia of the fluid begins to dominate dynamics of the system, and low supercritical where unstable flutter vibrations start to arise. The effectiveness of the designed optimal controller is validated by comparisons with the corresponding passive solutions. Affiliations:
 
3.  Pisarski D., Myśliński A.^{♦}, Online adaptive semiactive vibration damping of slender structures subject to moving loads, ICOEV2017, International Conference on Engineering Vibration, 20170904/0907, Sofia (BG), pp.1, 2017 Abstract: In this paper, the problem of the optimal control of a structure subjected to a moving load has been studied. In contrast to the previous works of the authors, focused on openloop strategies, this paper has been devoted to an adaptive closedloop control, where the switched damping strategy is subject to realtime adaptation according to the measured speed of the moving load.
 
4.  Pisarski D., Bajer C.I., Dyniewicz B., Szmidt T., Distributed control of smart cantilever structure, ETAMM, Emerging Trends in Applied Mathematics and Mechanics, 20160530/0603, Perpignan (FR), pp.1, 2016 Abstract: The work presents a novel distributed vibration control method of twin cantilever beams system coupled by a set of magnetorheological elastomers. The control is realized by a change of magnetic field influencing elastomers’ mechanical properties. The objective is to stabilize the system with the optimal rates of decrease of the energy. The control is based on an easy for practical implementation distributed statefeedback structure. It employs a set of communication channels to exchange the state information between the neighboring controllers. The performance of the designed method is validated by means of the numerical experiments. In terms of the assumed metrics, the proposed distributed method significantly outperforms the passive case and is competitive to standard centralized control. Affiliations:
 
5.  Pisarski D., Decentralized stabilization of vibrating structures, XXIV FrancuskoPolskie Seminarium Mechaniki, 20161017/1018, Warszawa (PL), pp.1, 2016 Abstract: The work presents novel concepts of decentralized structural vibration control. The control is assumed to be realized by a semiactive device. The objective is to stabilize a vibrating system with the optimal rates of decrease of the energy. Two types of controllers, heuristic and optimal, are considered. Both controllers employ easy for implementation decentralized statefeedback structures. They utilize a set of communication channels to exchange the state information between the neighboring controllers. The performance of the designed controllers is validated by means of the numerical experiments performed for double cantilever system equipped with a set of elastomers with controlled viscoelastic properties. In terms of the assumed objectives, the proposed distributed method significantly outperforms the passive damping cases and is competitive to standard centralized control. Affiliations:
 
6.  Pisarski D., Bajer C.I., Dyniewicz B., SemiActive Stabilization of Smart Structures Subjected to Impact Exctitation, PCMCMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 20150908/0911, Gdańsk (PL), pp.805806, 2015 Abstract: In the work, a novel control method to stabilize vibrations of high structures is presented. The control is realized by changes of the stiffness parameters of the structural couplers. A seismic pulse excitation applied to the structure is submitted as a kinematic excitation. For such a representation the designed control law provides the best rate of the energy dissipation. Performance in different structural settings is studied by means of the stability analysis. Then, the efficiency of the proposed strategy is examined via numerical simulations. In terms of the assumed energy metric, the controlled structure outperforms its passively damped equivalent by over 50 percent. Keywords:Structural control, semiactive control, smart materials, smart buildings, stabilization Affiliations:
 
7.  Pisarski D., On realtime distributed adaptation of structures subjected to travelling loads, SolMech 2014, 39th Solid Mechanics Conference, 20140901/0905, Zakopane (PL), pp.107108, 2014  
8.  Pisarski D., Bajer C.I., Moving load passage optimization via semiactive control system, CMM 2011, 19th International Conference on Computer Methods in Mechanics, 20110509/0512, Warszawa (PL), pp.18812, 2011 Abstract: In this paper the optimal control system for straight passage of moving load is considered. The magnitude of the moving force is assumed to be constant by neglecting inertial forces. The response of the system is solved in modal space. The idea of semiactive control manner for 1D continuum subjected to travelling load was first based on the numerical investigations. Then, the switching control strategy was formulated. The methods of computing the optimal switching times was developed by means of adjoint state. We present the efficient way of calculating such a switching times. The effect of predeflected guideway is also considered. Several examples demonstrate the efficiency of the proposed techniques. The controlled system widely outperforms passive solutions. Keywords:optimization, beams, sandwich structures, vibrations, industrial problems Affiliations:
