Double Actuator Research Articles

A New Hybrid Stepper Motor, Compliant Piezoelectric Micro-Tweezer for Extended Stroke.

The revolutionary economic potential of micro and nanotechnology is already recognized. Micro and nano-scale technologies that use electrical, magnetic, optical, mechanical, and thermal phenomena separately or in combination are either already in the industrial phase or approaching it. The products of micro and nanotechnology are made of small quantities of material but have high functionality and added value. This paper presents such a product: a system with micro-tweezers for biomedical applications-a micromanipulator with optimized constructive characteristics, including optimal centering, consumption, and minimum size, for handling micro-particles and constructive micro components. The advantage of the proposed structure consists mainly in obtaining a large working area combined with a good working resolution due to the double actuation principle: electromagnetic and piezoelectric.

Reconfiguration control allocation of actuator faults for tailless aircraft with low aspect ratio

The triaxial attitude control of the tailless aircraft depends heavily on the effectiveness of the actuators. Still, the actuators have redundancy characteristics, cross-coupling of rudder effect, and so on. Therefore, the reconfigurable control allocation of the tailless aircraft under typical actuator faults is deeply studied in this paper. The effectiveness and rationality of the incremental control allocation method based on quadratic programming are thoroughly verified for application to maximize the residual control ability of the aircraft, ensure that the aircraft can still complete the flight mission typically, and guarantee flight safety. According to the research principle of surface failures from slight to severe, three typical rudder surface faults are designed successively: Efficiency loss of single actuator, single actuator stuckness, and double actuators combined stuckness. On this basis, the mechanism of reconfiguration allocation after actuator failures is studied, and the residual control ability of the actuator after loss is fully explored. What’s more, the range of allowable reduction of efficiency of each actuator and the acceptable stuck angle range of each actuator are explored, and the most severe failure in the combination of double actuators stuck is obtained. The attitude controller is designed with incremental backstepping (IBKS). The reconstruction allocation adopts a quadratic programming allocation method based on an effective set solver, which can be seamlessly connected with the IBKS method to improve the control accuracy and disturbance immunity effectively.

Simultaneous wing shape and actuator parameter optimization using the adjoint method

Increasing attention to urban air mobility with distributed electric propulsion causes an increased interest in propeller aircraft design and optimization. Various studies have focused on designing and optimizing the aerodynamic performance of wings and propellers. However, existing studies optimized the wing and propeller separately due to the numerical challenges in simulations and optimization. It is not clear to what extent high-fidelity coupled wing-propeller aerodynamic optimization can benefit the propeller aircraft design. As a first step to answer the above question, this study develops the capability to simultaneously optimize the wing shape and actuator parameters. We use a high-fidelity computational fluid dynamics solver to simulate the wing aerodynamics, and the propeller is modeled as an actuator disk. We develop a smoothed actuator disk formulation that allows us to change the actuator's location and radius during the optimization, along with the wing shape. We use the discrete adjoint approach to compute the derivatives and couple them with a gradient-based optimization framework. The benefit of the above adjoint-based optimization framework is that it can use a large number of design variables to allow large design freedom for both wing and actuator. We perform 15 optimizations to evaluate how various actuator parameters impact the wing aerodynamic performance; both single and double actuator configurations are considered. We observe that the spanwise location and outer radius are the two most important actuator parameters, and using more actuator parameters as the design variables result in better performance. For example, optimizing the wing shape while allowing the actuator location and outer radius to move exhibits 11.4% more drag reduction compared with optimizing the wing shape while fixing the actuator parameters. This study serves as the starting point for more detailed high-fidelity coupled wing-propeller aerodynamic optimizations.

Free Surface Double Actuator Disc Theory and Double Multiple Streamtube model for in-stream Darrieus hydrokinetic turbines

According to the literature, the last improvement to the Actuator Disc Theory for hydrokinetic turbines in channel flows included blockage ratio and Froude number as independent variables in a single-disc formulation. The authors attempted to solve these equations in a Blade Element Momentum model for axial-flow turbines, ensuring satisfactory results.To our best knowledge, no Blade Element Momentum code was developed for Darrieus rotors including an extended double-disc theory so far. In this perspective, a Free Surface double-disc LMADT is implemented to solve the governing equations in a Double Multiple Streamtube model, facilitating the assessment of In-Stream Darrieus hydrokinetic turbines. Rigid Lid equations, derived for higher-depth applications, are included for completeness. A further numerical procedure allows to set up the channel flow from downstream and update the inflow data due to the resistance induced by the turbine operation in a subcritical flow.In addition to corrections for flow curvature, shading of the downstream flow due to the shaft, and losses due to the mechanical struts, this work encloses an effective sub-model accounting for the turbine installation depth. The Double Multiple Streamtube model is finally validated with previous experimental data of a Darrieus turbine deployed in a narrow channel.

Fluid-structure and electric coupled analysis of a valveless microfluidic system using metal-capped piezoelectric actuator

A new actuator in which a metal cap is combined with a bimorph piezoelectric element was proposed, and the liquid transfer and mixing performance when applied to valveless microfluid devices was numerically verified. Especially to ensure high versatility, we aimed to be able to demonstrate sufficient performance with a general power supply of AC 100 V, 50 Hz in Japan. Two drive modes were considered: a single actuator applied only to the upper surface of the circular tank and double actuators applied to the upper and lower surfaces. In the liquid transfer performance test, it was found that the flow rate was improved by about 19 times in the single MC-BMP (Metal-Capped Bimorph) and about 82 times in the double MC-BMP compared with the conventional BMP (Bimorph). On the other hand, in the mixing performance test, it was found that the mixing index was improved about 2.3 times in the single MC-BMP and about 2.9 times in the double MC-BMP compared with the conventional BMP. Furthermore, protrusions were inserted into the flow path at the connection between the main flow path and the piezoelectric actuator, and the effect on the mixing performance was also verified. As a result, the mixing performance was greatly improved by inserting the protrusions, and finally, when two protrusions were inserted in the double actuation of the new MC-BMP, the mixing index reached 85%. From these results, we were able to verify the superiority of the proposed new MC-BMP, the usefulness and versatility that can be used with the general power supply of 100 V and 50 Hz. The findings can be expected to contribute to the design and development of pumps and mixers for various valveless microfluid devices.

Control position of the double nozzles on the Y (+) and Y (-) axis of 3D symmetric bilateral printing using G-Code

The most widely used universal Cartesian 3-Dimensional (3D) Printing today is not fast enough. However, by applying double nozzles, the process for making symmetric bilateral product can be done in half of the time. A symmetric bilateral product is an object that has the same size on the right and left sides. So, the method can be implemented by having double actuators that are mounted by a nozzle on each side. Both nozzles, called as Y and -Y nozzle, move on the same time and distance but in different direction. Besides that, an appropriate mechanical support is needed to be prepared, so that the motors can move in different direction at the same time. Therefore, a design simulation for two Y actuators was carried out. The simulation and the data taking were using actuator simulation software. The simulation results shows that the G-code can control two Y actuators with 99.64% accuracy with average error of 0.216% for revolution speed, and 100% accuracy with average error 0% for distance. The motor can move in different directions with the same type of screw.

Axial strain effect on translational motion property of carbon nanotube thermal actuator

ABSTRACT The possibility of strain engineering of linear motion property of the double walled carbon nanotube thermal actuator is explored in this paper. Systematical study of axial strain effect on linear motion property of the carbon nanotube thermal actuator is conducted using molecular dynamics, and real-time controlling method for double walled carbon nanotube thermal actuator by applying axial strains is proposed as well. It is found that the axial strain has great influences on the linear motion behaviour of the thermal actuator, implying that the strain effect has potential to control the property of nano actuator. The strain effect and its mechanism are revealed by investigating the variation of thermal driving force and intertube distance as the axial strain is applied. The intertube interaction affected by axial strain is analyzed using the intertube stiffness constant drawn from the analytical model. The valuable conclusions for strain engineering of nanoscale actuator are obtained. This work suggests the great potential of strain effect to be real-time control method to nanoelectromechanical system and provides new ideas for the application of carbon nanotube thermal actuator.

Consensus of nonlinear multi-agent systems with fuzzy modelling uncertainties via state-constraint hybrid impulsive protocols

In this paper, the nonlinear multi-agent system which contains uncertainty and is controlled by state-constraint impulsive protocol is taken into consideration. For the uncertainty of the multi-agent system, it is replaced by fuzzy logic system approximately and a judgement strategy which only contains the relative information with neighbors is proposed in this paper. In order to do research in state-constraint impulsive protocol, three kinds of impulsive control protocols which conclude partial input saturation, double actuator saturation and single actuator saturation are discussed. Then, some sufficient conditions of the system are obtained to reach consensus. Finally, some numerical simulation examples are provided to prove the effectiveness of the theoretical analysis.

ANSYS Based Simulation of Single and Double Coil Axial Active Magnetic Bearing using Finite Element Method

For the successful design of an AMB system, proper material selection and actuator design is a must. The strength of the magnetic force depends upon the current density of the winding, actuator dimension and the gap between the actuator and the rotor. This paper presents the design of a U-O type single-actuator and a double-actuator Active Magnetic Bearing (AMB) utilizing ANSYS Maxwell 17.1 software. In double actuator AMB the actuators are placed at 180 degrees apart. In this study, Finite Element Method (FEM) based simulation has been performed for two different structures and their magnetic properties for instance- flux pattern, force, flux density and inductance are obtained for various air-gaps. Analysis has also been done with the change in current density by varying in the coil turns. The comparative results of single and double coil AMB are illustrated in 2-D and 3-D plots.

Energy Efficiency and Dynamic Analysis of a Novel Hydraulic System with Double Actuator

At present, increased attention has been given to energy efficiency promotion and energy saving of manufacturing equipment and systems. Hydraulic system is widely used in engineering machinery industries; however, the high energy consumption and low energy efficiency of which limit its development and application. On the basis of previous research on hydraulic system, an energy-efficient hydraulic system with double actuator is proposed in this study. This hydraulic system can reduce the energy consumption by reusing the potential energy loss of the system. In this novel hydraulic system, the chambers of two actuators are connected with rod by pipes and valves. During the operating processes, the falling operation of one cylinder and the returning operation of the other are synchronized. That is, one actuator remains at the top point performing the demanded operation, whereas the other one remains at the bottom performing the corresponding operation. System models are developed to address the energy consumption and dynamic performance of the proposed hydraulic system. This hydraulic system is applied into a press to study its energy-saving mechanism and dynamic performance during transient under various working conditions. On the basis of the simulation and experimental results, energy and production efficiency are compared and discussed. Results show that in comparison with the energy and time consumption of the original 630 kN hydraulic press, the energy-saving potential has reached 17.34%, and the production efficiency can be improved by 18.85%.

Edge event-triggered control and state-constraint impulsive consensus for nonlinear multi-agent systems

In the paper, some consensus problems of multi-agent system controlled by edge event-triggered strategy and state-constraint impulsive are taken into account. For the state-constraint impulsive protocol, two types of control protocols which contain input saturation and double actuator saturation are put forward. With regard to the edge event-triggered control, we propose the rule of it and let the time of the edge event-triggered be impulsive time to avoid the Zeno-behavior. Then, compared to the control method of others, we can greatly reduce the cost in the process of exchanging information. Next, some sufficient conditions of the system are required to reach consensus. In the end, a few examples are exploited for testing and checking the theoretical analyses.

Experimental analysis on force and correction factor of an active magnetic thrust bearing

Active magnetic thrust bearing (AMTB) is a device which is used to support an object by controlling the magnetic field. In practice, there is lot of difference between theoretical force and actual force developed between the stator and rotor of an AMTB. This difference is mainly due to fringing, leakage, variation in material properties, misalignments, vibrations, and temperature effects, etc. The difference is also varying with the air gap between stator and rotor and the current supplied. In this work, an experimental approach has been proposed to study the loss factor and efficiency of an Active Magnetic Thrust Bearing. A prototype of AMTB has been made and experimented at different air gaps. Based on the study of single acting actuator, the control performance of a double actuator has been studied. From the study of single acting actuator efficiency and double acting actuator control performance, an optimum air gap has been suggested.

Seismic performance on stiffness and hysteresis loop of interior wall-slab joint for tunnel form building designs to British standard

Wall-slab is a system suitable for use in the field of high-rise building where the main load resisting system is in the form rigidly connected wall-slab member. This paper presents the performance of a full-scale wall-slab joint in tunnel form system subjected to lateral cyclic loading. The objectives are to determine seismic behavior on the hysteresis loops and stiffness. Interior wall-slab joint was tested up to failure drift of 1.5%. The biggest hysteresis loops were occurred at the closest to the double actuator. The stiffness of wall-slab joint started to decrease from 0.25% drift until 0.5% drift and lost it stiffness after 0.5% drift. Incretion of the percentage of reinforcement bars in the wall-slab and proper detailing at joint is required for seismic loading. Keywords: wall-slab; hysteresis; stiffness; joint; cyclic

Parametric Study of Paraelectric and Peristaltic Pulsed DBD Plasma Actuation for Aerodynamic Flow Control Based on PIV

Using single and multiple dielectric barrier discharge plasma actuators, the velocity fields induced by steady, pulsed, asynchronous, and duty cycle plasma actuation are studied based on Particle Image Velocimetry (PIV). First, the flow fields induced by a single dielectric barrier discharge with different discharge models and actuation parameters are investigated. According to the velocity distributions, a parametric study on the influence of excitation voltages, carrier frequencies, pulse frequencies, and duty ratios on plasma actuation is presented and the optimum actuation parameters are provided. Emphatically, through double actuators alternating discharge, the peristaltic acceleration plasma actuation, a new plasma actuation mode, has been proposed and studied. The efficiency of the plasma actuators in steady and pulsed discharge modes is explored. The velocity field induced by plasma actuation with different phase angles and duty cycle ratios is acquired and the momentum transfer characteristics of the flow field were discussed. Finally, based on the above-mentioned results, the technical superiority and mechanism of the peristaltic acceleration induced by multiple dielectric barrier discharge plasma actuators are analyzed.

3D Backward-Facing Step Flow Structure Modification with Plasma Actuators

Backward-Facing Step (BFS) shape is a common configuration found in several engineering applications. The turbulent flow structure in the backside of a BFS leads to risky situations. Then, flow control is a useful technique to achieve safe conditions. In recent years, plasma devices have become an interesting technology with high importance for flow control because of non-moving parts, fast time response and low energy consumption. This paper presents the experimental investigation of a set of Dielectric Barrier Discharge (DBD) plasma actuators placed on the rounded edge of a BFS and its capability for flow control by wind tunnel testing. In contrast to the other studies, the behaviour of the plasma actuators in presence of 3D flow over a BFS was investigated. Firstly, a parametric study by analysing the location and the influence of the electrical parameters of the DBD plasma actuator was performed at a freestream velocity of 6 m/s using Particle Image Velocimetry (PIV). It was seen that actuator with -45° wall jet provides the highest flow control at 30 kVpp and 2.5 kHz with a reattachment length reduction of 65.6% referred to plasma off case. This configuration was optimized and compared with a double actuator for a higher velocity (10 m/s). The manufacturing complexity of the double actuator recommends the use of a simple actuator due to the fact that they have similar results, with a 30% of reattachment point reduction approximately at 10 m/s. Anyhow, the results confirm the authority of plasma actuators to modify the flow structure behind a BFS.

Configuration of redundant drive wire mechanism using double actuator modules

A new wire mechanism called “redundant drive wire mechanism” (RDWM), driven by double actuator modules (DAMs) is introduced. When RDWM is used for producing multi-directional motions using DAMs, the number of wires increases and the wire matrix would become complicated. This makes finding and checking the candidates difficult. Therefore, we introduce an easier and simpler approach for judging RDWM candidates, which includes two procedures: conversion of the wire matrix to a new form, and judgment of candidates using the essential component of the new form of wire matrix related to the global motion. This paper shows a fast and convenient method for judging whether an RDWM candidate can produce the resultant forces needed to achieve required motions. The examples demonstrate the validity of the new method in dealing with RDWM candidates containing many wires.

Kinematical and static force analysis on redundant drive wire mechanism with velocity constraint modules to reduce the number of actuators

This study proposes new wire mechanism called “the redundant drive wire mechanism” (RDWM), driven by double actuator modules. The RDWM is configured with velocity constraint modules (VCMs) that provide high-acceleration global and fine local motions. Suitable RDWM candidates are found by combining the kinematic analysis with static force analysis. The study also clarifies the role of VCMs in reducing the required number of actuators while keeping the orientation of the top plate. We propose a judgment procedure with three steps: a static force analysis in the whole motion space, a kinematic analysis that finds the active constraint space wherein the top plate can produce velocity and a static force analysis in this active constraint space. The proposed judgment procedure and the role of VCMs are validated by examples.

English

English

The Design and Control of Electromagnetic Actuator for Six-Axis Force Sensor Dynamic Calibration

In order to calibrate six-axis force sensor dynamic characteristics, double E-type electromagnetic actuator is operated by electric magnets. It is capable of sending sinusoidal excitation signal with variable amplitude and frequency continuously. The theoretical modeling and linearization is established. Repetitive control plus proportion control method is presented. And the stabilization is analyzed by small gain theorem. Simulation results show, compared to PID control method, the proposed method has higher trajectory accuracy, no steady-state error and the slightly smaller bandwidth. It has theoretical and practical value to improve six-axis force sensor dynamic characteristics measurement accuracy.

Separation control by means of plasma actuation on a half cylinder approached by a turbulent boundary layer

The flow around a half cylinder (i.e. an immersed cylinder in a flat plate) approached by a turbulent boundary layer is studied, with the aim to control separation via steady Dielectric Barrier Discharge (DBD) plasma actuation. The electric wind induced by a single DBD plasma actuator is studied in quiescent air to understand the role of the different driving parameters and how the cylindrical shape influences the downstream development of the induced electric wind. A double DBD plasma actuator is then placed on the cylinder and the influence of the position of the actuator is studied in order to find the best achievable control. Comparison of the controlled and uncontrolled cases, using both hot-wire anemometry and pressure measurements, shows that a reduction of the separation bubble is possible. By optimizing the position of the double actuator, a reduction of up to 30% of the drag is achieved. The present geometry is chosen as a generic model of the flow around the front corners (A-pillars) of a truck cabin and the work is performed with the long-term vision to be able to reduce drag on trucks.