Multi-DOF compensation of piezoelectric actuators with recursive databases

2018 ◽  
Vol 66 (8) ◽  
pp. 656-664 ◽  
Author(s):  
Christopher Schindlbeck ◽  
Christian Pape ◽  
Eduard Reithmeier
Keyword(s):  
Tracking Control ◽  
Control Design ◽  
Cross Coupling ◽  
Piezoelectric Actuators ◽  
Nonlinear Effects ◽  
Open Loop ◽  
Degree Of Freedom ◽  
Decoupling Control ◽  
Open Loop Control ◽  
Loop Control

Abstract Piezoelectric actuators are subject to nonlinear effects when voltage-driven in open-loop control. In particular, hysteresis and creep effects are dominating nonlinearities that significantly deteriorate performance in tracking control scenarios. In this paper, we present an online compensator suitable for piezoelectric actuators that is based on the modified Prandtl-Ishlinskii model and utilizes recursive databases for the compensation of nonlinearities. The compensator scheme is furthermore extended to systems with more than one degree of freedom (DOF) such as Cartesian manipulators by employing a decoupling control design to mitigate inherent cross-coupling disturbances. In order to validate our theoretical derivations, experiments are conducted with coupled trajectories on a commercial 3-DOF micro-positioning unit driven by piezoelectric actuators.

Randomized Algorithms for Open-Loop Control of Clutch-to-Clutch Transmissions

1999 ◽  
Vol 121 (3) ◽  
pp. 508-517 ◽  
Author(s):  
Albert Yoon ◽  
Pramod Khargonekar ◽  
Kumar Hebbale
Keyword(s):  
Optimal Control ◽  
Randomized Algorithms ◽  
Automatic Transmission ◽  
Computational Cost ◽  
Control Design ◽  
Open Loop ◽  
Transmission Model ◽  
Open Loop Control ◽  
Loop Control ◽  
Randomized Search

In this paper, randomized algorithms are used to design an open-loop control for a clutch-to-clutch shift automatic transmission and to study the robustness of that control. The open-loop control design problem can be posed as an optimal control problem but because of the computational cost associated with each simulation and the complexity of the transmission model, classical results from optimal control theory are not a practically feasible approach for this problem. We apply randomized search algorithms for optimization to these problems and present some promising results.

scholarly journals A Specific Methodology of Creep Compensation for Piezoelectric Actuators by Open-Loop Control

2013 ◽  
Vol 281 ◽  
pp. 141-145 ◽  
Author(s):  
Xuan Wang ◽  
Valérie Budinger ◽  
Yves Gourinat
Keyword(s):  
Viscoelastic Model ◽  
Piezoelectric Actuators ◽  
Open Loop ◽  
Creep Model ◽  
Relaxation Model ◽  
Open Loop Control ◽  
Loop Control ◽  
Positioning Systems ◽  
Creep Effect ◽  
Nonlinear Viscoelastic Model

Piezoelectric actuators exhibit creep behavior in open-loop operation, which may lead to unaffordable errors in high precision static positioning systems. An inversion-based compensation strategy by open-loop control is presented for reducing creep effect. The approach utilizes a nonlinear viscoelastic model to portray creep phenomenon, which consists of a linear spring, a nonlinear dashpot and a series of nonlinear Voigt elements. It is shown that for the presented creep model the step responses are very similar to the piezoelectric actuators. In order to compensate creep effect, a concept of voltage relaxation in piezoelectric actuators is proposed. And the voltage relaxation model tantamount to the inverse creep model is derived using a PID closed-loop control system. Experimental results prove that, by insertion of voltage relaxation model in open-loop operation, creep effect is attenuated markedly in piezoelectric actuators.

Design and Analysis of a Micro-Positioning Stage

2011 ◽  
Author(s):  
Jau-Liang Chen ◽  
Yan-Ming Chen
Keyword(s):  
Piezoelectric Actuator ◽  
Open Loop ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Flexure Hinge ◽  
Open Loop Control ◽  
Maximum Displacement ◽  
Rotational Angle ◽  
Loop Control ◽  
Positioning Stage

The purpose of this research is trying to design a 6 degree-of-freedom micro-precision positioning stage with monolithic mechanism. It is hoped that this stage can reach 10 μm strokes along linear axis and with rotational angle no less than 50 μrad. The dimension of this positioning stage should be less than 200 mm × 200 mm × 50 mm. By using flexure hinge and piezoelectric actuator, this stage can achieve nanometer resolution. From the experimental results, it is found that the stage can achieve a maximum displacement of 29.3 μm in X axis; 11.94 μm in Y axis; and 6.74 μm in Z axis. The stage can also achieve a maximum rotation of 405.41 μrad around Z axis; 57.18 μrad around X axis; and 63.72 μrad around Y axis. With open loop control, we have shown that the minimum step for the stage is 110 nm in X-axis; 45 nm in Y axis; and 30 nm in Z-axis.

Quiet Seating Control Design of an Electromagnetic Engine Valve Actuator

2001 ◽  
Author(s):  
Chun Tai ◽  
Tsu-Chin Tsao
Keyword(s):  
Control Design ◽  
Tail Length ◽  
Open Loop ◽  
Open Loop Control ◽  
Loop Control ◽  
Engine Valve ◽  
Electromagnetic Valve ◽  
Valve Motion ◽  
Seating Position ◽  
Variable Valve

Abstract The control of engine valve seating velocity has been identified to be crucial for the application of an electromagnetic valve (EMV) actuator for camless variable valve timing engine operations. Analysis shows that the EMV actuator becomes unstable when the engine valve is hold steady close to the seating position. As such, valve motion under open loop control is sensitive to disturbances and suffers poor repeatability. Therefore, closed-loop control is required to achieve desirable quiet-seating performance consistently. A linear plant model was constructed based on a gray-box approach that combines mathematical modeling and system identification. A controller was developed with H∞ loop-shaping method to stabilize the EMV actuator. The performance of this control design is demonstrated by experimental results. “Seating velocity” and “seating tail-length” are defined and used to evaluate the control system performance.

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