Centrifugal microfluidics has been widely applied in the sample-in–answer-out systems for the analyses of nucleic acids, proteins, and small molecules. However, the inherent characteristic of ...unidirectional fluid propulsion limits the flexibility of these fluidic chips. Providing an extra degree of freedom to allow the unconstrained and reversible pumping of liquid is an effective strategy to address this limitation. In this study, a wirelessly charged centrifugal microfluidic platform with two rotation axes has been constructed and the flow control strategy in such platform with two degrees of freedom was comprehensively studied for the first time. Inductively coupled coils are installed on the platform to achieve wireless power transfer to the spinning stage. A micro servo motor is mounted on both sides of the stage to alter the orientation of the device around a secondary rotation axis on demand during stage rotation. The basic liquid operations on this platform, including directional transport of liquid, valving, metering, and mixing, are comprehensively studied and realized. Finally, a chip for the simultaneous determination of hexavalent chromium Cr(VI) and methanal in water samples is designed and tested based on the strategy presented in this paper, demonstrating the potential use of this platform for on-site environmental monitoring, food safety testing, and other life science applications.
•A new fractional-order proportional-Clegg integrator in reset applications is investigated.•Fractional-order proportional-Clegg integrator can avoid Zeno solution.•Stability of fractional-order ...reset systems is analyzed in the frequency domain.
This paper deals with fractional-order reset control systems and their stability. The possibilities of use of a new fractional-order proportional-Clegg integrator (FPCI) in reset applications are investigated. The key feature of this controller is to tune its order α to achieve an optimized system performance, especially referred to avoid the Zeno solution. The stability of reset control systems is generalized for such fractional-order systems. Fractional- and integer-order reset controllers are designed and compared for the velocity control of a servomotor. Simulated and experimental results are given to show the benefits of using FPCI on the servomotor performance.
In this paper, various methods for synchronizing the position of tape materials during automatic assembly have been analyzed. Methods for ensuring a constant relative position of two materials have ...been considered. A mechatronic transport system has been proposed, containing a servomotor, a linear guide with a ball screw, a movable carriage, a servomotor rotation angle sensor, and a photoelectric sensor for marks printed with a certain step on one of the tapes. Methods and control algorithms for the created mechatronic transport system have been proposed and described, which make it possible to ensure high assembly quality and the required position of the assembly components relative to each other. Numerical simulation of the proposed algorithms showed their high reliability and adaptability.
•Shear and extensional deformation resulted in a qualitatively similar ink transfer trends in both shear thickening and viscoelastic fluids..•Shear-induced ink trasfer was reduced in magnitude ...compared to extension in both non-Newtonian cases.•Extensional thickening enhanced the ink transfer in both non-Newtonian fluids.•Onset of extensional or shear thinning resulted in a plateau in the ink transfer.
In the presented study, we have investigated the effect of a complex flow field consisting of a combination of both shear and extensional deformation on the liquid transfer from an idealized gravure cell. The study was conducted for two classes of non-Newtonian fluid; a shear and extensional thickening nanoparticle dispersion and a extensional thickening viscoelastic polymer solution with a constant shear viscosity. The shear thickening fluid was a dispersion of fumed silica nanoparticles in polypropylene glycol and the viscoelastic fluid was a solution of polyethylene oxide (PEO) in water. The idealized gravure printing experiments were conducted using a combination of linear servo motor used to impose an extensional flow and a rotational servo motor to impose a shear flow during pickout. The fluid pickout from the gravure cell was studied as a function of the magnitude of the extensional and shear deformation rates. The fluid filament interface profile evolution during the pickout process was examined using a high speed camera. For the shear thickening fluid, the pickout resulting from a pure extensional flow field was found to be enhanced compared to Newtonian fluids at moderate velocities, resulting from the extensional thickening of the fluid. However, at large stretching velocities the pickout was found to decay dramatically due to extensional thinning of the fluid at large extension rates. The pickout behavior of the shear thickening fluid resulting from a pure shear field was found to exhibit a qualitatively similar trend to that of the extensional pickout although the pickout fraction was significantly smaller. Superposition of shear and extensional flow was found to initially improve pickout by driving the overall deformation rate higher and introducing an asymmetry in the gravure cell dewetting. At large rates, shear negatively affected pickout by causing an early onset of extensional thinning. In viscoelastic fluids, thickening of the extensional viscosity was found to enhance both the pure shear-induced pickout as well as the pure extensional-induced fluid pickout, with the shear-induced pickout relatively smaller compared to the extensional-induced pickout. For superimposed shear and extensional deformation, an enhancement in the fluid pickout was observed at certain velocity regimes, likely associated with the asymmetric dewetting from the gravure cavity wall assisted by the superimposed flows.
Abstract
At present automated technology is a trend and is easy to access, user friendly and easy to monitor. Having pet can be an enjoyment in our life. In this paper a prototype has been proposed ...to solve the problem of providing food and water for all types of pet when owner is residing away from home such as lockdown situation. By the application of this prototype, the owner can supply food and water to the pet at their preferred scheduled time. The system proposed is controlled through an ATMEGA32 Microcontroller. A conical structure created using ply board (collected from waste material) for reserving the pet’s food. A servomotor has been interfaced to control the outflow of the food through a PVC pipe connected to the bowl. The bowl is placed on a load cell to inspect the weight of food. The owner can assign the timing and quantity of food through a keyboard to supply food depending on the instantaneous weight of the food in the bowl. By using float sensor water level in the container has been monitored and refilled.
This paper focuses on the problem of adaptive output feedback fault tolerant control for a nonlinear hydro‐turbine governing system. A dynamic mathematical model of the system is established, which ...aims to investigate the dynamic performance of the model under servomotor delay and actuator faults. Then, a fault estimation adaptive observer is proposed to achieve online real‐time diagnosis of system faults. Based on the online fault estimation information, an observer‐based adaptive output feedback fault tolerant controller is designed. Furthermore, under reasonable assumptions, the results demonstrate that the closed‐loop control system can achieve global asymptotic stability by Lyapunov function. Finally, the numerical simulation results are presented to indicate the satisfaction control effectiveness of the proposed scheme.
The demand for the mass production of micro-lens arrays (MLAs) is increasing. An MLA is fabricated through an injection molding process, and its mold is manufactured by a five-axis high-precision ...machine tool using a small diameter endmill. A visual examination is not available to judge the quality of the mold while machining. Therefore, an effective process monitoring technology must be developed. A promising approach is to apply a servomotor current to in-process monitoring because as long as the servomotor works well, no external sensors, capital investment, or maintenance processes are required. From this perspective, a machine learning-based shape error estimation method using only the servomotor current is proposed. To explore the relationship between the motor current generated during micro-milling and the shape error of the mold, the servomotor current in
X
-,
Y
-, and
Z
-axes was recorded, and the corresponding shape error of the MLA mold was measured after machining. Input data were prepared by converting time-domain servomotor current data to frequency-domain data using short-time Fourier transform and reducing the dimensions of the data via principal component analysis. In terms of a meaningful label for the output data, the average shape error in the machined area corresponding to each window was provided. The input/output relationships were used to train five different machine learning models, and the accuracy of shape error estimation using each model was evaluated. In addition, the estimation accuracies using the
X
-,
Y
-, and
Z
-axes were compared to find the axis that senses the shape error with the highest accuracy. The results show that the non-linear method using the
X
-axis servomotor current information closest to the machining point achieved the highest shape error estimation accuracy.
This work aims to develop a novel system, including software and hardware, to perform independent control tasks in a genuine parallel manner. Currently, to control processes with various sampling ...periods, distributed control systems are most commonly utilized. The main goal of this system is to propose an alternative solution, which allows simultaneous control of both fast and slow processes. The presented approach utilizes FPGA (Field Programmable Gate Array) with Nios II processor (Intel Soft Processor Series) to implement and maintain instances of independent controllers. Instances can implement FDMC (Fast Dynamic Matrix Control) and PID (Proportional-Integral-Derivative) control algorithms with various sampling times. The FPGA-based design allows for true independence of controllers’ execution both from one another and the managing processor. Also, pure parallel execution allows for implementing slow and fast controllers in the same device. The complete flexible system with a matrix of controllers working in parallel in real-time was tested with both simulated and actual control processes (servomotor), yielding the same results as fully simulated experiments.
•The article presents a new method of measuring the static coefficient of fibre friction in a semi-automated way.•The analytical model of the belt friction coefficient was theoretically derived.•The ...paper is intended for accurate engineering measurements.•Can be used to declare the coefficients of unknown combinations of contacting materials of fibre and a cylindrical surface.
The paper aims to present a new method measuring the belt friction coefficient by the original computer-controlled measuring set. The essential elements of this semi-automated assembly are a digital force gauge and a digital servomotor. The Dynamixel MX64T servomotor with the externally installed shaft is a reliable, accurate and affordable instrument for examining frictional force and the belt friction coefficient, in dependence on the set constant rotational speed of the shaft. The new measurement method is realized by a double arrangement of the measuring assembly by winding the fibre onto the roller surface of the external shaft of the digital servo-motor and pulling the fibre over the external roller surface by the digital servomotor. The paper is intended for accurate engineering measurements or university scientific-research measurements, especially when it is necessary to declare the coefficients of unknown combinations of contacting materials of fibre and the roller surface, or the need to explore the properties of new types of fibres. The view of the tribological issues is physical-technical because virtually the relationships between the coupled physical phenomena of the same measuring set and the influences of the parameters of the sophisticated technical equipment on these phenomena are used.
One of the disadvantage of solar panel as a renewable energy is lack of power output when the solar panel is not directly leading to the sun. To increase the output power of solar panel, an active ...solar tracker based on the horizon coordinate system of solar has been developed. The solar horizon coordinate system used to determine the position of the sun at every single time, thus the solar panel's position to the sun is more precise. This device consists of arduinouno as control system, two servo motors as a panel drive, a PLX-DAQ program as a data monitoring, ACS - 712 as the current sensor, and a DC voltage sensor as the output voltage sensor. Sensor characterization shows that ACS-712 measures current in mA orde and has a maximum relative error of 4.25%, meanwhile the voltage sensor detects the output voltage up to 15 Volt and has the maximum relative error of 4.34%. The output power of this device increases 83,89% to the other active solar panels. To determine the effect of altitude and azimuth data, measurements were carried out in two different cities, there are Bekasi city and Tangerang city. The results show that the output power in both cities differed by 77.7%.
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