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This paper evaluates the effectiveness and performance of ionic polymer metal composite (IPMC)-based active vibration control scheme equipped with the Kalman estimation algorithm. To assess the vibration attenuation efficiency, a rotating flexible manipulator has been modelled integrating two IPMC actuators following the modal approach. The elastic...
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The two-inertial system is a typical motion control problem with compliance between the motor and load, where the resonance makes it very challenging to regulate the load response and stabilize the motor at the same time. Concerned with setpoint tracking, disturbance rejection, and internal stability, an observer based Active Vibration Control solu...
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... Based on Eq. (19), the estimated state is given by [53]. ...
This paper reports electromechanical dynamics modeling and microscopic vibration suppression for a high-speed macro–micro manipulator with structural flexibility and parameter perturbation. The macro–micro manipulator contains an air-floating macro-motion platform and a macro-fiber-composite (MFC) micromanipulator. The electromechanical dynamics model is derived by combining the assumed mode method and the asymmetric Prandtl-Ishlinskii hysteresis model. Then, a robust control strategy combining a perturbation H-infinity controller with a Kalman filter is proposed to compensate for the hysteresis nonlinearity and suppress the microscopic vibration during and after the macro motion. In particular, an additive perturbation is used to estimate the model uncertainties from the varying end mass and all other unknown dynamics. Also, the Kalman filter is designed to improve the signal-to-noise ratio of the displacement detection based on the process and measurement noises. Several experiments are conducted to validate the effectiveness and feasibility of the proposed dynamic model and robust controller. The elastic vibrations during and after macro motion are significantly suppressed even with the parameter perturbation. Thus, the proposed control strategy can improve the manipulation stability, robustness, and accuracy.
... Piezoelectric materials have the advantages of fast response and excellent actuation capabilities (Xie et al., 2017). The studies in active control of smart structures using piezoelectric actuators have become more attractive (Bandopadhya and Njuguna, 2010). ...
Auto-regressive moving average with exogenous excitation (ARMAX) model based experimental identification and vibration suppression of a flexible piezoelectric manipulator are conducted. Experimental identification based on ARMAX models with different orders is conducted. To remove the spurious modes that do not correspond to structural modes, a balanced model reduction method based on the Hankel singular value is employed. After balanced transformation and model reduction, the identified ARMAX model with a high order is transformed into a reduced-order controllable and observable system. Comparative experimental results show that the identified reduced-order model matches closely with the system dynamics. Therefore, an optimal discrete multi-poles shifting controller, which combines the multi-poles recursive shifting method and linear quadratic regulator (LQR) control, is proposed. The first complex conjugate poles pair of the system is shifted to some desired positions by solving a discrete algebraic equation. The weighting matrixes of the LQR are determined based on the solution of the discrete algebraic equation. Then, multi-poles of the identified model are shifted through recursive applications of the reduced-order poles shifting method. Experimental results show that vibrations of the manipulator are significantly diminished. Consequently, the effectiveness of the proposed controller is proven.
... For tracking first three modes of cantilevered plate, all states of the system need to be available. Since the measurement of all states of the system is difficult, an observer is used to estimate states of the system (Dong et al. 2006;Bandopadhya and Njuguna 2010). Kalman filter is employed to online estimate first three modes of the smart plate. ...
The area of vibration control is evolving rapidly primarily due to the high demand of lightweight automotive structures. To achieve desired vibration characteristics of the product in field, extensive vibration testing is required of the product in a laboratory. In this study, a novel technique is presented for generating desired structural transient vibrations in a product in a laboratory. A cantilevered test-plate instrumented with piezoelectric patches is made to track desired transient vibration curves. Finite element technique is used for mathematical modeling and optimal tracking control is used to simultaneously track first three vibration modes of the plate. Presented strategy can be used to do dynamic vibration testing of a structure by forcing the structure to experience same transient vibrations that it is expected to experience while in field.
... However, it is impossible to model and active control all these modes due to the computational and control limitations. In practice, the reduced order models of flexible structures are always developed by modal truncation, where only the dominant modes are considered [18]. Consequently, the problem of spillover associated with the un-modeled but often non-negligible modes is unavoidable, and the spillover effect will cause instability of the closed loop system [19]. ...
This paper presents experimental identification and vibration suppression of a flexible manipulator with piezoelectric actuators and strain sensors using optimal multi-poles placement control. To precisely identify the system model, a reduced order transfer function with relocated zeros is proposed, and a first-order inertia element is added to the model. Comparisons show the identified model match closely with the experimental results both in the time and frequency domains, and a fit of 97.2% is achieved. Based on the identified model, a full-state multi-poles placement controller is designed, and the optimal locations of the closed loop poles are determined where the move distance of the closed loop poles is the shortest. The feasibility of the proposed controller is validated by simulations. Moreover, the controller is tested for different locations of the closed loop poles, and an excellent performance of the optimal locations of the closed loop poles is shown. Finally, the effectiveness of the proposed controller is demonstrated by experiments. Results show that the vibrations of the expected modes are significantly diminished. Accordingly, multi-mode vibrations of the manipulator are well attenuated.
... But it is impossible to model and active control all these modes due to the computational and control limitations. In practice, the reduced order models of flexible structures are always developed by modal truncation, where only the dominant modes are considered [18]. Consequently, the problem of spillover associated with the un-modeled but often non-negligible modes is unavoidable, and the spillover effect will cause instability of the closed loop system [19]. ...
This paper presents experimental identification and vibration suppression of a flexible manipulator with non-collocated piezoelectric actuators and strain sensors using optimal multi-poles placement control. To precisely identify the system model, a reduced order transfer function with relocated zeros is proposed, and a first-order inertia element is added to the model to compensate the non-collocation. Comparisons show the identified model match closely with the experimental results both in the time and frequency domains, and a fit of 97.2% is achieved. Based on the identified model, a full-state multi-poles placement controller is designed, and the optimal locations of the closed loop poles are determined. The feasibility of the proposed controller is validated by simulations. Moreover, the controller is tested for different locations of the closed loop poles, and an excellent performance of the optimal locations of the closed loop poles is shown. Finally, the effectiveness of the proposed controller is demonstrated by experiments. Results show that the vibrations of the expected modes are significantly diminished. Besides, vibrations of the higher modes are also slightly suppressed. Accordingly, multi-mode vibrations of the manipulator are well attenuated, and the tip displacement converges quickly with the proposed method.
... Since measurement of all the states of system is difficult, an observer is used to estimate states of the system. The standard plant equation required for Kalman estimator [15] expressed as: ...
... Sensor signal sensed by sensor piezoelectric patch is conditioned, filtered and then fed to PXI controller through SCB-68 connector box. In the controller Kalman observer estimates first two modes of the plate and computes optimal control voltage as per optimal control law given in equation (15). Control voltage is then suitably amplified and applied on piezoelectric actuator patch. ...
A novel technique is presented for exciting desired transient vibrations in a structure. A cantilevered plate instrumented with piezoelectric sensor and actuator is used as a test-structure. Finite element model of the test-plate is developed using Hamilton's principle. Finite element model is reduced to first two modes using orthonormal modal truncation and then this reduced model is converted into a state-space model. Tracking optimal control is then employed to obtain desired transient curves simultaneously, of first two modes of vibration. Theoretical findings are verified by conducting experiments, for experimentation, Kalman observer is used to estimate first two modes and Labview software is used for interfacing. Presented strategy can be used to do dynamic vibration testing of a product by forcing the product to experience same transient vibrations that it is expected to experience in field.
... IPMCs, a type of smart material transducer, are implemented in the proposed manipulation system due to their intrinsic properties which make them desirable for this application, including very low mass, custom geometries, scalability, biocompatibility (for use in vitro and in vivo), flexibility and compliance, low power consumption and the ability to accurately achieve both micro and macro deflections without any gearing or other mechanisms [5][6][7]. IPMCs present a unique and smart system for cell manipulation due to their ability to work well in fluid and cellular environments as well as their natural compliance giving them a 'soft touch' when interacting with sensitive materials and/or in sensitive environments. Employing the soft and compliant IPMC actuators as cell and microorganism manipulators will present a solution for safe handling and manipulation of biological cells. ...
A precise and robust controller has been developed and implemented on a novel ionic polymer-metal composite (IPMC) actuated micro-manipulator to demonstrate its ability to enable safe and reliable manipulation of biological cells. A 2 degree-of-freedom (2DOF) control structure was employed to enable the system to be optimised for both the disturbance response (DR) and set-point (SP) tracking. The controller is adaptively tuned using a model-free iterative feedback tuning (IFT) approach which is ideal for operation in unknown cellular environments and handling the time-varying behaviour of the IPMCs themselves. IFT experiments have tuned the IPMCs to an 87% and 81% performance improvement in DR and SP respectively. Experiments then reveal that the tuned controller has equipped the manipulator with an accuracy of <7.1% of full scale, with up to 7° of motion in both axes. The controller has also demonstrated its ability to naturally cope with load disturbances up to 10 mN.
... The interest in IPMCs over the last two decades has resulted in significant advances in the manufacturing and materials processing [59][60][61], characterization [62], modeling [63][64][65], design [66], control [67], and application of IPMCs for actuation in soft bio-inspired systems [68], sensing [69], and even energy systems [70][71][72]. This issue and issue 4(4) contain eight papers that cover current research interest of IPMC technologies. ...
