Mechanics and Control
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ISSN 2083-6759
e-ISSN: 2300-7079
Issue Date
2011
Volume
Vol. 30
Number
No. 3
Description
Journal Volume
Mechanics and Control
Vol. 30 (2011)
Projects
Pages
Articles
Modelling of the semi-active suspension system
(2011) Gorczyca, Przemysław; Rosół, Maciej
The paper is concerned with a mathematical model of the Semi-Active Suspension system (SAS) of a vehicle equipped with the magnetorheological rotary brake manufactured by the Lord Corporation. SAS is a laboratory system animating the suspension action of a car quarter. A simulation model written in the MATLAB/Simulink environment is shown. The parameters of the mathematical model are identified by optimization procedures based on experimental data collected in the real-time. The mathematical model is verified. It means that appropriate system trajectories of SAS and the simulation model are compared.
Virtual recollocation of measurement signals in active vibration control systems
(2011) Gosiewski, Zdzisław
Collocation of sensors and actuators is an important feature of all motion control systems of active structures. Collocated systems provide great advantages from a stability, passivity, robustness and an implementation viewpoint. However it is not always possible to collocate the control actuators with sensors. Active magnetic bearings (AMBs) are examples of such systems. The paper presents a new method for recollocating the axes or planes of measurement to the axes or planes of actuation. Applying methods known from the control systems theory, such as state-space models, observers and transformations to canonical forms it is possible to calculate the transformation matrix that recollocates the measurement signals from the locations of sensors to the locations of actuators. The approach is illustrated with an analytical and numerical example of a rigid rotor supported by AMBs. The results confirm the correctness of the proposed method.
Gain-scheduled state-feedback control for active cancellation of multisine disturbances with time-varying frequencies
(2011) Heins, Wiebke; Ballesteros, Pablo; Bohn, Christian
The paper presents a discrete-time LTV controller for the rejection of harmonic disturbances with time-verying based on a state-augmented observer-based state-feedback controller with a time-verying internal model and a scheduled state-feed back gain. The control design method is based on quadratic stability for LPV systems. The design is carried out in discrete time and the controller can easily be implemented on real-time hardware.
Active vibration control system for 3D mechanical structures
(2011) Koszewnik, Andrzej Piotr; Gosiewski, Zdzisław
The active vibration control system for 3D mechanical structures is presented in the paper. The steel space framework which consists of 126 steel bars and 44 aluminium joints is a subject of our investigations. It is equipped in two piezoelectric stacks which are a part of chosen vertical bars in a plane X-Z. Bars, joints and piezo-stacks have got glue connections. The mathematical model was decoupled to change Two Input Two Output (TITO) system into two Single Input Single Output (SISO) systems. Such approach allowed us to design simple control laws with help of computer simulation procedure. In the last chapter the investigations on the laboratory stand of the active vibration control system with local controllers PD are described. Experimental results have proved that these PD controllers work good increasing the damping level. Additional damp in the system causes the excellent vibration reduction for the whole mechanical structure.
Feed-forward compensation for nonlinearity of vibrating plate as the sound source for active noise control
(2011) Mazur, Krzysztof; Pawełczyk, Marek
Active Noise Control (ANC) systems are usually designed in the feed-forward structure with adaptive linear control filters. However, performance of such systems, when a vibrating plate is used as the secondary source, may be poor due to significant non-linearity of the plate response. The linear systems are then unable to cope with higher harmonics generated by the nonlinearity. One solution to this problem is to apply a nonlinear ANC algorithm. However, it adds additional complexity to this layer. It is particularly severe for multichannel systems, where the algorithms are complex by themselves, and making them nonlinear may significantly reduce their scalability. In this paper, another approach is proposed. Multiple actuators are mounted on a single plate, in order to effectively excite more vibration modes and generate a higher acoustic power, than in case of a single actuator. The response of the vibrating plate as the sound source is then linearized with a set of nonlinear finite impulse response filters, operating individually for each actuator. The Filtered-x LMS algorithm is adopted to update parameters of the nonlinear filters. The control system is experimentally verified and obtained results are reported.