Bintang Yang

Non-Contact Translation-Rotation Sensor Using Combined Effects of Magnetostriction and Piezoelectricity

Precise displacement sensors are an important topic in precision engineering. At present, this type of sensors typically have a single feature of either translation or rotation measurement. They are also inconvenient to integrate with the host devices. In this report we propose a new kind of sensor that enables both translation and rotation measurement by using the combined effect of magnetostriction and piezoelectricity. As a proof of concept, we experimentally realized a prototype of non-contact translation-rotation precise sensor. In the current research stage, through both theoretical and experimental study, the non-contact displacement sensor is shown to be feasible for measuring both translation and rotation either in coarse or fine measurement. Moreover, owing to its compact, rigid structure and fewer components, it can be easily embedded in host equipment.

Design of a safety escape device based on magnetorheological fluid and permanent magnet

In this research, a novel safety escape device based on magnetorheological fluid and permanent magnet is designed, manufactured, and tested. The safety escape device with magnetorheological fluid and permanent magnet can provide an increasing braking torque for a falling object by increasing the magnetic field intensity at the magnetorheological fluid. Such increase is realized by mechanically altering the magnetic circuit of the device when the object is falling. As a result, the falling object accelerates first and then decelerates to stop in the end. Finite element analysis is used to determine some of the specifications of the safety escape device for larger braking torque and smaller size. Finite element analysis results are also used for theoretical study and establishment of the dynamic model of the safety escape device. A prototype is realized and tested finally. The experimental test results show that the operation of the prototype conforms to the prediction by the dynamic model and validates the feasible application of magnetorheological fluids in developing falling devices.

Non-linear modelling of multilayer piezoelectric actuators in non-trivial configurations based on actuator design parameters and piezoelectric material properties

Current models of non-linear electromechanical behaviours of piezoactuators are mostly intended for actuator configurations where the strain of the piezoelectric material is directly used as the linear output. On the other hand, in the design of piezoactuators, there exist non-trivial configurations where the internal strains of the piezoelectric materials manifest externally in the form of bending and curving rather than simple elongation or contraction, it is also important to predict the non-linear performance of the actuator based on the design parameters. Therefore, it is the intent of this article to present a model that enables calculation of the quasi-static mechanical response of piezoelectric multilayer actuators in non-trivial configurations. It is based on the polarization hysteresis loop and butterfly curve of its constituent piezoelectric material. Using an energy-based formulation, the model takes into account the non-piezoelectric sections as well as the mechanical boundary conditions of the actuator. Furthermore, a three-layer lead zirconium titanate bimorph with both ends clamped is considered in this study. Model calculation of its relationship between input voltage V and midpoint vertical displacement X is carried out based on ferroelectric hysteresis data of the bimorph material from the literature. The calculation results are then validated by measurements.

Adaptive infinite impulse response system identification using opposition based hybrid coral reefs optimization algorithm

An efficient global adaptive algorithm is required to determine the parameters of infinite impulse response (IIR) filter owing to the error cost surface of adaptive IIR system identification problem being generally nonlinear and non-differentiable. In this paper, a new bio-inspired algorithm, called opposition based hybrid coral reefs optimization algorithm (OHCRO) is applied for the IIR system identification problem. Coral reefs optimization algorithm (CRO) is a novel global algorithm, which mimics the behaviors of corals’ reproduction and coral reef formation. OHCRO is a modified version of CRO, on the one hand utilizing opposition based learning to accelerate global convergence, on the other hand cooperating with rotational direction method to enhance the local search capability. In addition, the Laplace broadcast spawning and power mutation brooding operator are used to maintain the diversity. The simulation studies have been performed for the performance comparison of genetic algorithm, particle swarm optimization and its variants, differential evolution and its variants and the proposed OHCRO for well-known benchmark examples with same order and reduced order filters. Simulation results and comparative studies justify the efficacy of the OHCRO based system identification approach in terms of convergence speed, identified coefficients and fitness values. In conclusion, OHCRO is a promising method for adaptive IIR system identification.

Study on Formalizable Aircraft Assembly Process Planning Knowledge

Domain knowledge representation is various and domain-concerned. The aircraft assembly process planning (A2P2) is a special domain, a lot of things should be taken into account, and the knowledge representation of A2P2 is complicated. It is focused on the knowledge representation of A2P2 in this paper. Based-on case, the framework of A2P2 knowledge is presented. The main considerations of A2P2 are analyzed, the transformation and reassembly of native A2P2 knowledge is studied, the features of A2P2 is acquired, and the formalizable framework of A2P2 is proposed. With BNF, a formal description of A2P2 knowledge is given.

Dynamic/static displacement sensor based on magnetoelectric composites

This study presents a dynamic/static displacement sensor based on both end fixed Terfenol-D/PZT (lead zirconate titanate) magnetoelectric composites. Owing to the fixed boundary condition, the magnetostriction of Terfenol-D under the magnetic field is limited and the stress acts on PZT through mechanical coupling, and finally, an induced voltage is generated due to the piezoelectric effect in PZT. The magnetic field applied on the magnetoelectric composites varies with the displacement of the permanent magnet which represents the displacement to be measured. In that case, the determination of displacement can be transformed into determining the variation of the magnetic field. The experimental results manifest that the frequency of magnetoelectric voltage is the same as the frequency of displacement. The dynamic displacement sensitivity of this sensor increases with the increase in the input frequency in the low frequency range and the decrease in the length of the air gap. The sensitivity is 6.549 mV/μm with a 0.75 mm air gap for dynamic displacement at 10 Hz and 0.84 μV/μm with a 2.5 mm air gap and an external magnetic field at 1 kHz for static displacement. It can be concluded that the displacement measuring mechanism based on the magnetoelectric effect is a promising robust and accurate method.This study presents a dynamic/static displacement sensor based on both end fixed Terfenol-D/PZT (lead zirconate titanate) magnetoelectric composites. Owing to the fixed boundary condition, the magnetostriction of Terfenol-D under the magnetic field is limited and the stress acts on PZT through mechanical coupling, and finally, an induced voltage is generated due to the piezoelectric effect in PZT. The magnetic field applied on the magnetoelectric composites varies with the displacement of the permanent magnet which represents the displacement to be measured. In that case, the determination of displacement can be transformed into determining the variation of the magnetic field. The experimental results manifest that the frequency of magnetoelectric voltage is the same as the frequency of displacement. The dynamic displacement sensitivity of this sensor increases with the increase in the input frequency in the low frequency range and the decrease in the length of the air gap. The sensitivity is 6.549 mV/μm ...

Effects of Tunable Angle for Vortex Generators on Aerodynamic Performances of Airfoils

Vortex generators (VGs) are commonly adopted to control the flow separation, and many researches have investigated their effects on the aerodynamic performance of wind turbines. However, nearly no attentions are paid to the VGs’ installation angle. Thus, in this paper, to investigate the effects of the VGs’ installation angle on airfoils, numerical simulations are conducted by CFD on the finite wing of NACA0012. According to the finite airfoil with or without VGs, three-dimensional models are established and numerical simulations are carried out in detail. It could be seen clearly that the VGs’ installation angle produces a significant impact on the aerodynamic performances. For some installation angles, special ranging from 45° to 90°, VGs can improve the lift-drag ratio apparently, even by 34.5%. While angle ranges from 15° to 30°, VGs negatively influence the lift-drag ratio. Furthermore, the fluctuation phenomenon is discussed through analysis of the streamlines and vortices. Based on those results, optimal aerodynamic performances could be achieved by the active control of the VGs’ installation angle.

Modeling of the Electromagnetic Drive Torque on the Permanent Magnet in a Novel Drive Mechanism

Analytical models of vibration exciters and shakers are of great importance to their dynamic analysis and control. Furthermore, the modeling of the drive torque/force of the driving principle plays a key role in the modeling of an entire driving system. This paper aims to find a more detailed analytical model of the electromagnetic drive torque on the permanent magnet with a new shape in a novel driving mechanism. The proposed model contains all the related parameters instead of treating them as only one variable. Two methods of the permanent magnet installation are firstly introduced and compared. Based on the magnetic charge model, torque models of the bipolar cylindrical permanent magnet and partial bipolar cylindrical permanent magnet are then obtained. Thereupon then the final model with a composite shape is gained by combining the cylindrical and partial cylindrical ones. Moreover, all analytical models are verified by finite element method and it is found the final detailed model can characterize the electromagnetic drive torque in a high accuracy.

The Adaptive Feedback Control with Dynamic Feed-Forward Compensation of the Giant Magnetostrictive Actuator

The giant magnetostrictive actuator (GMA) has been used in more and more areas. But due to the existence of the nonlinear hysteresis, how to realize the high precision drive of the GMA is becoming a key problem. The paper proposes a new control algorithm of the adaptive feedback control with the dynamic feed-forward compensation. Under the expected displacement of sinusoidal signal (1Hz of the frequency and 20μm of the amplitude), the experimental maximum error ratio can reach to 5.15% and mean square error ratio is 2.024%.The paper also gives an experimental comparison with other algorithms.

Design and Modeling of a New Inchworm Linear Motor

This paper presents a research work for the design and modeling of a new inchworm linear motor. The three actuators of the motor are based on electromagnetic and permanent magnetic combined drive. The actuator may generate large output force, large displacement and quick response. A permanent magnet cam is designed to realize the continuous and smooth movement for the actuator. The motion equation of the cam mechanism is established and analyzed by SIMULINK from which the optimal contour of the cam may be confirmed. Then the general dynamic model of the linear motor is established with a 4DOF lumped parameter system.