1. |
Ostrowski M., Błachowski B., Popławski B., Pisarski D., Mikułowski G., Jankowski Ł., Semi‐active modal control of structures with lockable joints: general methodology and applications,
STRUCTURAL CONTROL AND HEALTH MONITORING, ISSN: 1545-2255, DOI: 10.1002/stc.2710, pp.e2710-1-24, 2021Streszczenie: In this study, a novel modal control strategy by means of semi-actively lockable joints is proposed. The control strategy allows for a directed flow of energy between vibrational modes, which makes it suitable not only for vibration attenuation purposes but also for energy scavenging driven by electromechanical energy harvesters. The proposed control strategy is an extension of the prestress-accumulation release (PAR) technique; however, it introduces also new concepts that increase the efficiency of the overall control system. Contrary to the PAR, the proposed method requires measurement of both strains in the vicinity of the semi-active joints and translational velocities that provide global information about system behavior. The latter aspect requires the control system to be organized within a hierarchical feedback architecture. The benefit from this higher complexity of the control system is its better performance compared to the PAR. The proposed semi-active modal control not only attenuates structural vibration faster, but it also achieves this goal with a smaller number of switches implemented in the joints. The effectiveness of the proposed methodology has been demonstrated on structures equipped with two lockable joints. Two practical examples have been investigated: one employs the concept of vibration-based energy harvesting for a two-story frame structure, while the second one reduces vibration of an eight-story frame structure subjected to kinematic excitation. Słowa kluczowe: energy harvesting, lockable joint, modal coupling, semi-active control, vibration attenuation Afiliacje autorów:
Ostrowski M. | - | IPPT PAN | Błachowski B. | - | IPPT PAN | Popławski B. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Mikułowski G. | - | IPPT PAN | Jankowski Ł. | - | IPPT PAN |
| | 140p. |
2. |
Wasilewski M., Pisarski D., Adaptive semi-active control of a beam structure subjected to a moving load traversing with time-varying velocity,
JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2020.115404, Vol.481, pp.115404-1-20, 2020Streszczenie: A novel method for adaptive semi-active vibration control of structures subjected to a movingload is studied. The velocity of the load is assumed to be time-varying. The controller consistsof an internal model of the moving load, which is being frequently updated to accommodatechanges in the load's velocity. The control method relies on a near-optimal switching con-trol law that is based on the solution to the algebraic Lyapunov equation. The infinite-horizonformulation of the control problem enables us to use efficient numerical algorithms for adap-tive recomputing of the control signal. The asymptotic stability of the closed-loop system andperformance improvement in comparison to the passive method are analysed and formallyproven. The controller is tested by means of numerical experiments involving a flexible beamequipped with a set of semi-active viscous dampers. We investigate three distinct simulationscenarios, which correspond to highly non-uniform motions of the load that consist of accel-eration, deceleration and temporary halt phases. The results of the simulations are comparedto passive and optimal open-loop strategies. Słowa kluczowe: vibration control, adaptive control, semi-active control, moving load, stabilisation Afiliacje autorów:
Wasilewski M. | - | IPPT PAN | Pisarski D. | - | IPPT PAN |
| | 200p. |
3. |
Pisarski D., Konowrocki R., Jankowski Ł., Scalable distributed optimal control of vibrating modular structures,
STRUCTURAL CONTROL AND HEALTH MONITORING, ISSN: 1545-2255, DOI: 10.1002/stc.2502, Vol.27, No.4, pp.e2502-1-21, 2020Streszczenie: A scalable optimal control method for structural vibration mitigation is studied. The method relies on a structure's partitioning that leads to a set of dynamically interconnected subsystems. Each subsystem is operated with an individual subcontroller that collects the local state information and collaborates with the neighboring subcontrollers to estimate a short time prediction of the interconnecting forces defining the subsystem's boundary conditions. Using the extended model that represents the subsystem's dynamics together with the evolution of its boundary conditions, each subcontroller computes the control decision based on the solution to a finite‐time horizon optimal control problem. In order to cope with the changes in the boundary conditions, the optimal solution is computed repetitively according to the receding horizon scheme. The method is validated numerically for a cantilever structure equipped with actively controlled electromagnetic actuators and subjected to a variety of initial condition scenarios. The performance of the designed controller is tested by comparisons to the centralized and isolated decentralized controllers. The introduced system partitioning and distributed controller allow performing parallel computing which makes the method fully scalable and applicable to large‐scale structures. The computational complexity of the designed distributed control is studied for different settings in the modeling of the subsystem's boundary conditions. Słowa kluczowe: active control, distributed control, modular structure, scalable optimization, stabilization Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Konowrocki R. | - | IPPT PAN | Jankowski Ł. | - | IPPT PAN |
| | 140p. |
4. |
Pisarski D., Szmidt T., Konowrocki R., Decentralized semi‐active structural vibration control based on optimal system modelling,
STRUCTURAL CONTROL AND HEALTH MONITORING, ISSN: 1545-2255, DOI: 10.1002/stc.2624, Vol.27, No.11, pp.e2624-1-20, 2020Streszczenie: The problem of decentralized semi‐active stabilization of vibration of a beam structure is studied. The decentralized controller's architecture is attained by means of optimal system modelling. In this approach, based on a specially designed and optimized set of basis functions, the solution to the continuous Euler-Bernoulli beam equation is approximated by a discrete system, where the mass and stiffness matrices ensure that the assumed stabilizing control law can be operated by using solely the local state information. The performance of the method is examined through numerical experiments for a series of free‐vibration scenarios with comparison to competitive decentralized and centralized control strategies. The performance impact of the selection of the parameters of the optimal system model is also studied. The designed method allows practical modular arrangements of the control system and is applicable to large‐scale structures. Słowa kluczowe: bilinear system, decentralized control, polynomial basis, semi-active control, stabilization Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Szmidt T. | - | IPPT PAN | Konowrocki R. | - | IPPT PAN |
| | 140p. |
5. |
Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Modal energy transfer by controlled structural connections,
DIAGNOSTYKA, ISSN: 1641-6414, DOI: 10.29354/diag/116692, Vol.21, No.1, pp.61-70, 2020Streszczenie: This paper describes a semi-active control strategy that allows to transfer the vibration energy from an arbitrarily induced to a selected structural mode. The intended aim of the proposed control strategy is energy harvesting from structural vibrations. Another potential application is related to structural safety. In the paper, a mathematical model is first introduced to describe the phenomenon of vibrational energy transfer, and then, based on this model, an efficient semi-active control strategy is proposed. Finally, some problems related to measurement techniques are discussed. The effectiveness of the proposed methodology is demonstrated in an example of energy transfer between vibrational modes of a three-bar planar frame structure. Słowa kluczowe: vibration energy, modal control, lockable joint, modal coupling Afiliacje autorów:
Ostrowski M. | - | IPPT PAN | Błachowski B. | - | IPPT PAN | Jankowski Ł. | - | IPPT PAN | Pisarski D. | - | IPPT PAN |
| | 20p. |
6. |
Pisarski D., Myśliński A.^{♦}, Suboptimal distributed state-feedback control of semi-active vibrating systems,
JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2018.12.009, Vol.443, pp.637-651, 2019Streszczenie: A novel semi-active control method for mitigating structural vibration is studied. The method relies on distributed state information patterns and the solution to a suboptimal control problem that aims at replicating the switched structures of the optimal open-loop stabilizing controls. The optimality conditions and the method of solution of the suboptimal problem are discussed. The performance of this method is examined by means of numerical experiments performed for a double cantilever system equipped with a set of semi-active elastomers with controlled viscoelastic properties. The experiments were carried out for different controller architectures and a series of initial conditions. In terms of the assumed objectives, the proposed distributed control strategy significantly outperforms the passive damping strategies and is competitive with a standard centralized control. The proposed approach is general to a class of bilinear control systems concerned with smart structural elements. The practical aspects of the designed distributed controller are highlighted. Słowa kluczowe: distributed control, optimal control, bilinear system, stabilization, semi-active structure Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Myśliński A. | - | Systems Research Institute, Polish Academy of Sciences (PL) |
| | 200p. |
7. |
Wasilewski M., Pisarski D., Bajer C.I., Adaptive optimal control for seismically excited structures,
Automation in Construction, ISSN: 0926-5805, DOI: 10.1016/j.autcon.2019.102885, Vol.106, pp.102885-1-18, 2019Streszczenie: A novel adaptive control for structures subjected to seismic excitation is presented. The aim of the control is to provide a high stabilizing performance involving a limited computational burden while allowing for frequent update of the control decision to cope with the changes in the excitation characteristics. Consequently, the control is based on a computationally efficient solution to the infinite-horizon linear optimal control problem, which employs the autoregressive model for excitation signals and the alpha-shift method for a performance index. Based on numerical simulations involving an actively controlled 20-story building subjected to different earthquake scenarios, we demonstrate that the adaptive control outperforms the standard LQG and H∞ regulators. Our analysis of the controller's computational complexity has confirmed that the presented method can be successfully implemented in large-scale structures that are equipped with active control devices. Our follow up research will validate the performance of the designed control on a real environment platform and we will design an adaptive controller to mitigate vibration in semi-active structures. Słowa kluczowe: adaptive control, structural control, autoregressive model, vibration, optimal stabilization Afiliacje autorów:
Wasilewski M. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN |
| | 140p. |
8. |
Wasilewski M., Pisarski D., Konowrocki R., Bajer C.I., A new efficient adaptive control of torsional vibrations induced by switched nonlinear disturbances,
INTERNATIONAL JOURNAL OF APPLIED MATHEMATICS AND COMPUTER SCIENCE, ISSN: 1641-876X, DOI: 10.2478/amcs-2019-0021, Vol.29, No.2, pp.285-303, 2019Streszczenie: Torsional vibrations induced in drilling systems are detrimental to the condition of the machine and to the effectiveness of the engineering process. The cause of vibrations is a nonlinear and unknown friction between a drill string and the environment, containing jumps in its characteristics. Nonlinear behaviour of the friction coefficient results in self-excited vibration and causes undesirable stick-slip oscillations. The aim of this paper is to present a novel adaptive technique of controlling vibrating systems. The scheme is based on the linear quadratic regulator and uses direct measurements of the friction torque to synthesize its linear dynamic approximation. This approach allows generating a control law that takes into account the impact of the friction on the system dynamics and optimally steers the system to the desired trajectory. The controller's performance is examined via numerical simulations of the stabilization of the drilling system. The proposed solution outperforms the comparative LQG regulator in terms of the minimization of the assumed cost functional and the overall stability of the control system under the nonlinear disturbance. Słowa kluczowe: vibration control, adaptive control, linear-quadratic-regulator, drilling control Afiliacje autorów:
Wasilewski M. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Konowrocki R. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN |
| | 100p. |
9. |
Szmidt T., Pisarski D., Konowrocki R., Semi-active stabilisation of a pipe conveying fluid using eddy-current dampers: state-feedback control design, experimental validation,
MECCANICA, ISSN: 0025-6455, DOI: 10.1007/s11012-019-00988-3, Vol.54, No.6, pp.761-777, 2019Streszczenie: An application of electromagnetic devices of the motional type (i.e. eddy-current dampers) to improve the dynamic stability of a cantilever pipe discharging fluid is proposed. When the flow velocity reaches a critical value, this system loses stability through the flutter. A contactless damping device is used. This actuator is made of a conducting plate attached to the pipe that moves together with it within the perpendicular magnetic field that is generated by the controlled electromagnets. During the motion the eddy currents in the plate and a resultant drag force of a viscous character are generated. First, an optimal control problem that aims to stabilise the system with the optimal rate of decrease of the system’s energy is posed and solved. Then a state-feedback parametrization of the obtained optimal control, which can be used in a closed-loop scheme is proposed. The effectiveness of the designed optimal controller is validated by making a comparison with the corresponding passive solutions on the specially designed and constructed experimental test stand of a pipe conveying air. Słowa kluczowe: fluid–structure interaction, electromagnetic device, eddy-current damper, optimal control, stabilisation, smart structure Afiliacje autorów:
Szmidt T. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Konowrocki R. | - | IPPT PAN |
| | 100p. |
10. |
Popławski B., Mikułowski G., Pisarski D., Wiszowaty R., Jankowski Ł., Optimum actuator placement for damping of vibrations using the prestress-accumulation release control approach,
SMART STRUCTURES AND SYSTEMS, ISSN: 1738-1584, DOI: 10.12989/sss.2019.24.1.027, Vol.24, No.1, pp.27-35, 2019Streszczenie: This paper proposes a quantitative criterion for optimization of actuator placement for the Prestress–Accumulation Release (PAR) strategy of mitigation of vibrations. The PAR strategy is a recently developed semi-active control approach that relies on controlled redistribution of vibration energy into high-order modes, which are high-frequency and thus effectively dissipated by means of the natural mechanisms of material damping. The energy transfer is achieved by a controlled temporary removal of selected structural constraints. This paper considers a short-time decoupling of rotational degrees of freedom in a frame node so that the bending moments temporarily cease to be transferred between the involved beams. We propose and test a quantitative criterion for placement of such actuators. The criterion is based on local modal strain energy that can be released into high-order modes. The numerical time complexity is linear with respect to the number of actuators and potential placements, which facilitates quick analysis in case of large structures. Słowa kluczowe: semi-active control, damping of vibrations, actuator placement, smart structures, prestress-accumulation release (PAR) Afiliacje autorów:
Popławski B. | - | IPPT PAN | Mikułowski G. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Wiszowaty R. | - | IPPT PAN | Jankowski Ł. | - | IPPT PAN |
| | 70p. |
11. |
Szmidt T., Pisarski D., Konowrocki R., Awietjan S.^{♦}, Boczkowska A.^{♦}, Adaptive damping of a double-beam structure based on magnetorheological elastomer,
SHOCK AND VIBRATION, ISSN: 1070-9622, DOI: 10.1155/2019/8526179, Vol.2019, pp.8526179-1-16, 2019Streszczenie: A method of vibration reduction based on activation of an MRE block that couples twin cantilever beams at their free ends is investigated. Four types of magnetorheological elastomers have been manufactured, and their rheological properties in a range of magnetic field intensities are established. Free vibrations of several double-beam structures with controllable damping members made of these MREs are investigated, and a method of semiactive control of such structures is proposed. The effects of compression of the elastomers and alignment of the magnets used to activate them are reported. The mathematical modeling of the system is verified experimentally. Afiliacje autorów:
Szmidt T. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Konowrocki R. | - | IPPT PAN | Awietjan S. | - | Warsaw University of Technology (PL) | Boczkowska A. | - | Warsaw University of Technology (PL) |
| | 70p. |
12. |
Pisarski D., Optimal control of structures subjected to traveling load,
JOURNAL OF VIBRATION AND CONTROL, ISSN: 1077-5463, DOI: 10.1177/1077546316657244, Vol.24, No.7, pp.1283-1299, 2018Streszczenie: The problem of the optimal semi-active 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 time-varying 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%. Słowa kluczowe: optimal control, structural control, semi-active control, vibration control, moving load Afiliacje autorów:
| | 45p. |
13. |
Pisarski D., Decentralized stabilization of semi-active vibrating structures,
MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 0888-3270, DOI: 10.1016/j.ymssp.2017.08.003, Vol.100, pp.694-705, 2018Streszczenie: A novel method of decentralized structural vibration control is presented. The control is assumed to be realized by a semi-active 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 state-feedback 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. Słowa kluczowe: structural control, decentralized control, smart structures, modular structures, stabilization Afiliacje autorów:
| | 45p. |
14. |
Pisarski D., Konowrocki R., Szmidt T., Dynamics and optimal control of an electromagnetically actuated cantilever pipe conveying fluid,
JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2018.06.045, Vol.432, pp.420-436, 2018Streszczenie: 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 self-excited 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 non-conservative 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 unstable or conservative state. For that purpose, we determine 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 rate 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 the 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. Słowa kluczowe: fluid–structure interaction, electromagnetic device, optimal control, stabilization, smart structure Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Konowrocki R. | - | IPPT PAN | Szmidt T. | - | IPPT PAN |
| | 35p. |
15. |
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: 0022-460X, DOI: 10.1016/j.jsv.2016.09.027, Vol.386, pp.265-282, 2017Streszczenie: 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 time-stepping procedure. The transition from one spatial finite element to another must be energetically consistent. In the case of the moving inertial load the classical time-integration 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. Słowa kluczowe: Mindlin plate, mass moving at varying speed, arbitrary trajectory, inertial load, space–time finite element method Afiliacje autorów:
Dyniewicz B. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN |
| | 35p. |
16. |
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: 0022-460X, DOI: 10.1016/j.jsv.2017.01.046, Vol.394, pp.333-347, 2017Streszczenie: 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 semi-active mode. The passive mode can be applied with materials exhibiting direction-dependent viscosity. Słowa kluczowe: plate vibration, moving load, intelligent damping layer, semi-active damping Afiliacje autorów:
Bajer C.I. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Szmidt T. | - | IPPT PAN | Dyniewicz B. | - | IPPT PAN |
| | 35p. |
17. |
Szmidt T., Pisarski D., Bajer C.I., Dyniewicz B., Double-beam cantilever structure with embedded intelligent damping block: Dynamics and control,
JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2017.04.033, Vol.401, pp.127-138, 2017Streszczenie: In this paper, a semi-active 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 state-feedback 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. Słowa kluczowe: Vibration control, Double-beam structure, Sandwich beam, Magnetorheological elastomer, Semi-active damping, Stabilization Afiliacje autorów:
Szmidt T. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN | Dyniewicz B. | - | IPPT PAN |
| | 35p. |
18. |
Pisarski D., Myśliński A.^{♦}, Online adaptive algorithm for optimal control of structures subjected to travelling loads,
OPTIMAL CONTROL APPLICATIONS & METHODS, ISSN: 0143-2087, DOI: 10.1002/oca.2321, Vol.38, No.6, pp.1168-1186, 2017Streszczenie: 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 real-time 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. Słowa kluczowe: adaptive control, moving load, online optimal control, sensitivity analysis, structural vibration control Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Myśliński A. | - | Systems Research Institute, Polish Academy of Sciences (PL) |
| | 30p. |
19. |
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: 0022-460X, DOI: 10.1016/j.jsv.2016.05.050, Vol.380, pp.37-50, 2016Streszczenie: 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. Słowa kluczowe: vibration, damping, smart materials, control, semi-active Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN | Dyniewicz B. | - | IPPT PAN | Bajkowski J.M. | - | Warsaw University of Technology (PL) |
| | 35p. |
20. |
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: 0093-6413, DOI: 10.1016/j.mechrescom.2016.10.005, Vol.78, pp.51-56, 2016Streszczenie: 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 relay-type control logic. In the experiment, the deformable granular coupler semi-actively 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 semi-active 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. Afiliacje autorów:
Bajkowski J.M. | - | Warsaw University of Technology (PL) | Bajer C.I. | - | IPPT PAN | Dyniewicz B. | - | IPPT PAN | Pisarski D. | - | IPPT PAN |
| | 25p. |
21. |
Pisarski D., Szmidt T., Bajer C.I., Dyniewicz B., Bajkowski J.M.^{♦}, Vibration Control of Double-Beam System with Multiple Smart Damping Members,
SHOCK AND VIBRATION, ISSN: 1070-9622, DOI: 10.1155/2016/2438902, Vol.2016, pp.2438902-1-14, 2016Streszczenie: 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 bang-bang 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. Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Szmidt T. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN | Dyniewicz B. | - | IPPT PAN | Bajkowski J.M. | - | Warsaw University of Technology (PL) |
| | 20p. |
22. |
Wasilewski M., Pisarski D., Bajer C.I., Adaptive stabilization of partially damaged vibrating structures,
Machine Dynamics Research, ISSN: 2080-9948, Vol.40, No.1, pp.65-82, 2016Streszczenie: In this paper, an online adaptive continuous-time 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. Słowa kluczowe: Vibration control, Adaptive control, Optimal control, Policy iterations, Hamilton-Jacobi-Bellman equation Afiliacje autorów:
Wasilewski M. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN |
| | 14p. |
23. |
Pisarski D.^{♦}, Canudas-de-Wit C.^{♦}, Nash Game Based Distributed Control Design for Balancing of Traffic Density over Freeway Networks,
IEEE Transactions on Control of Network Systems, ISSN: 2325-5870, DOI: 10.1109/TCNS.2015.2428332, Vol.3, No.2, pp.149-161, 2016Streszczenie: 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 two-players 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. Afiliacje autorów:
Pisarski D. | - | inna afiliacja | Canudas-de-Wit C. | - | CNRS (FR) |
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24. |
Pisarski D., Distributed Control Design for Structures Subjected to Traveling Loads,
MATHEMATICAL PROBLEMS IN ENGINEERING, ISSN: 1024-123X, DOI: 10.1155/2015/206870, Vol.2015, pp.206870-1-12, 2015Streszczenie: 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 life-time of the carrying structures. The results presented in the previous works of the author exhibited high performance of supports with an open-loop 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. Afiliacje autorów:
| | 20p. |
25. |
Dyniewicz B., Pisarski D., Konowrocki R., Semi-active control of track subjected to an inertial moving load,
VIBRATIONS IN PHYSICAL SYSTEMS, ISSN: 0860-6897, Vol.25, pp.147-152, 2012Streszczenie: 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. Słowa kluczowe: control, moving inertial load, vibrations, smart materials Afiliacje autorów:
Dyniewicz B. | - | IPPT PAN | Pisarski D. | - | IPPT PAN | Konowrocki R. | - | IPPT PAN |
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26. |
Pisarski D., Bajer C.I., Smart suspension system for linear guideways,
JOURNAL OF INTELLIGENT AND ROBOTIC SYSTEMS, ISSN: 0921-0296, DOI: 10.1007/s10846-010-9450-7, Vol.62, pp.451-466, 2011Streszczenie: This paper presents a new method for the semi-active 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 semi-active 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, bang-bang 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. Słowa kluczowe: Semi-active control, Smart suspension system, Vibration control, Linear guideway, Moving load Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN |
| | 20p. |
27. |
Pisarski D., Bajer C.I., Semi-active control of 1D continuum vibrations under a travelling load,
JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2009.09.006, Vol.329, pp.140-149, 2010Streszczenie: The paper presents a method for computing the response of a 1D elastic continuum supported by a set of semi-active 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 time-marching scheme allows us to continue a solution in successive layers with initial conditions taken from the end of previous stages. The semi-active 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. Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN |
| | 32p. |
28. |
Pisarski D., Bajer C.I., On the semi-active control of carrying structures under moving a load,
VIBRATIONS IN PHYSICAL SYSTEMS, ISSN: 0860-6897, Vol.24, pp.325-330, 2010Streszczenie: 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. Słowa kluczowe: Semi-active control, structural control, optimization, moving load Afiliacje autorów:
Pisarski D. | - | IPPT PAN | Bajer C.I. | - | IPPT PAN |
| | 6p. |
29. |
Pisarski D., Bajer C.I., Aktywne tłumienie drgań struny i belki pod obciążeniem ruchomym,
DROGI I MOSTY, ISSN: 1643-1618, Vol.8, No.4, pp.71-87, 2009 | | 6p. |