XY Stage Research Articles

Design and Control of Modular Compliant XY Positioning stage

The modular design and controller implementation of compliant XY stage having large motion range are presented.The design involves symmetric parallel kinematic configuration using compound parallelogram flexure module (CPM) with input-output decoupling properties. The architectural parameters are determined based on the performance metrics such as stiffness, resonance frequency and motion range etc. The FEA simulation predicts the range of motion of 12 mm along each working axes.A prototype is developed to assess the performances of the stage. The results exhibit the small deviation between the two working axes which reflects the better decoupled motions.The PID controller is implemented to achieve the accuracy of positioning with submicron resolution.

Modeling and compensation of a hollow XY stage based on hybrid reluctance actuators

In the field of beam pointing and optoelectronic imaging, there is a growing demand for control mechanisms that offer large stroke, and high bandwidth. These are precisely the characteristics of hybrid reluctance actuator, which therefore is increasingly being used in XY stage to replace piezo-actuator and voice coil motor. This study presents a hollow XY stage utilizing hybrid resistance actuators, aiming to adapt to optical applications with inherent nonlinearity and biaxial coupling, which are further modeled and compensated to mitigate their impacts. Firstly, the basic composition and working principle of the hollow XY stage are described, and the impact of its nonlinearity and biaxial coupling characteristics is elucidated. Secondly, the sources of nonlinearity and biaxial coupling are analyzed, and an analytical model of hybrid reluctance actuators is established. The magnetic leakage coefficient of the model is determined, and the accuracy of the model is verified by Finite Element Method (FEM) and experiment, demonstrating consistency with the analytical model's results. Furthermore, based on the nonlinear and biaxial coupling model, a compensator based on feedback linearization method is established, and verified through experiment. The results show that this method has a significant suppression effect on nonlinear and biaxial coupling, and the tracking error and cross-talk is obviously reduced, which proves the effectiveness of this compensation method.

Phantom-Enhanced High Mechanical Accuracy for Frame-Based Deep Brain Stimulation.

Deep brain stimulation (DBS) is a neurosurgical procedure that depends on high-accuracy targeting of structures to implant electrodes within the brain. The positioning of these electrodes in the brain determines the long-term efficacy of treating diseases such as Parkinson's disease, essential tremor, or dystonia.Misplaced electrodes in DBS can lead to poor efficacy and stimulation-induced side effects. Widespread targeting errors and variability have been published throughout the literature. As such,improvement in targeting accuracy is needed to enhance the quality of the procedures. A stereotactic phantom was utilized to test and adjust targeting before the surgical placement in the brain for 91 sequential electrodes.The tip of the microelectrode, the first rigid point in time, was measured and compared to the planned target.The technique utilized a to-target cannulawith an XY stage that allowed x-axis and y-axis adjustments and correction for inaccuracies relative to the phantom.A calculation was developed to convert anatomical angles (sagittal and coronal) provided by commercial planning stations to spherical angles to calculate points along a trajectory.Errorcalculations included each dimensional axis, Euclidean error, and radial error. Bends in the cannula and microelectrode were observed and corrected by referencing the phantom. All 91 first-pass tracks traversed the intended target, and three electrodes required a second mapping track beyond the first penetration due to neurophysiological and intraoperative testing. The results showed overall ultra-high (0-0.5 mm) to high (>0.5-1 mm) accuracy, an average Euclidean error of 0.66±0.30 mm, and a radial error of 0.45±0.28 mm with dimensional errors of less than 0.5 mm per axis. The utilization of a stereotactic phantom is an important tool to enhance the stereotactic targeting before insertion into the brain. This phantom technique yielded ultra-high to high accuracy in error calculations.Future methods and studies shouldfocus on error minimization to enhance these DBS mechanical accuracy and correlations with clinical outcomes.

Body-Mounted MR-Conditional Robot for Minimally Invasive Liver Intervention.

MR-guided microwave ablation (MWA) has proven effective in treating hepatocellular carcinoma (HCC) with small-sized tumors, but the state-of-the-art technique suffers from sub-optimal workflow due to the limitedaccuracy provided by the manual needle insertions. This paper presents a compact body-mounted MR-conditional robot that can operate in closed-bore MR scanners for accurate needle guidance. The robotic platform consists of two stacked Cartesian XY stages, each with two degrees of freedom, that facilitate needle insertion pose control. The robot is actuated using 3D-printed pneumatic turbines with MR-conditional bevel gear transmission systems. Pneumatic valves and control mechatronics are located inside the MRI control room and are connected to the robot with pneumatic transmission lines and optical fibers. Free-space experiments indicated robot-assisted needle insertion error of 2.6 ± 1.3 mm at an insertion depth of 80mm. The MR-guided phantom studies were conducted to verify the MR-conditionality and targeting performance of the robot. Future work will focus on the system optimization and validations in animal trials.

Piezoelectric-synchronized step emulsification for facile generation of microdroplet library with fluid-independent drop size regulation regime

Microdroplets play a crucial role in various applications based on microfluidics, including biomedicine, materials synthesis, and analytical chemistry. However, there is still an urgent need for a microdroplet preparation method that is simple in design, precise in droplet size control and meanwhile independent of the properties of the fluid. Here, we present a piezoelectric-synchronized step emulsification method. The drop formation process can be synchronized by the introduced periodic vibration via the piezoelectric element, which occurs in a specific frequency range determined by a dimensionless parameter. The competing between the step emulsification regime and the piezoelectric-triggered local flow rate fluctuation leads to various microscopic flow behavior. A novel instantaneous jetting regime is found to be responsible for the extended achievable drop size range. By combining the piezoelectric step emulsification and the XY stage control, we achieve facile production of microdroplet and hydrogel microsphere library in well plates, which is promising to be integrated as a low-cost drop-generating technique into bioassay instruments.

Research of Processing Technology of Longjing Tea with 'Baiye 1' Based on Non-Targeted Aroma Metabolomics.

Longjing tea is favored by consumers due to its refreshing and delicate aroma, as well as its fresh and sweet flavor. In order to study the processing technology of Longjing tea with 'Baiye 1' tea varieties, solid phase microextraction and gas chromatography-mass spectrometry were used to analyze the volatile components of Longjing tea in different process stages. The results revealed the identification of 275 aroma metabolites in the processing samples of Longjing tea. The sensory evaluation and principal component analysis revealed that the leaves of fresh (XY) and spreading (TF) were different from the leaves of first panning (YQ), second panning (EQ), final panning (HG), and fragrance enhancing (TX). The relative contents of geraniol (1199.95 and 1134.51), linalool (745.93 and 793.98), methyl salicylate (485.22 and 314.67), phenylethyl alcohol (280.14 and 393.98), 2-methylfuran (872.28 and 517.96), 2-butenal (56.01 and 154.60), and 2-hexenal (46.22 and 42.24), refreshing and floral substances in the XY and TF stages, were higher than other stages. The aroma contents of 2-methylfuran, furfural, 2-methyl-1-penten-3-one, 3-hexen-2-one, dodecane, hexanoyl hexanoate, 2,5-dimethyl-pyrazine, and methyl-pyrazine were found to be significantly positively correlated with the intensity of chestnut aroma. In conclusion, this study contributes to a better understanding of the composition and formation mechanism of chestnut-like aroma and provides new insights into the processing technology to improve the quality of albino green tea.

Iterative learning control with parameter estimation for non-repetitive time-varying systems

This paper presents an extension method of iterative learning control (ILC) to address the applications associated with non-repetitive time-varying systems (NTVSs). Conventional ILC approaches employ fixed nominal system models, but non-repetitive time-varying models may lead to accumulated model uncertainties, which fails to satisfy the robust convergence conditions. To tackle this issue, a novel ILC algorithm with parameter estimation is proposed using back propagation neural network. This algorithm incorporates an approach that utilizes Bayesian regularization training mechanism to accurately estimate non-repetitive time-varying parameters. Through comprehensive experiment on Monolithic XY Stage, the performance of proposed algorithm is validated to demonstrate its feasibility and effectiveness while handling tasks on NTVSs.

Development and testing of XY stage compliant mechanism

Development and testing of XY stage compliant mechanism

On-line six-degree-of-freedom errors measurement and compensation for XY stages

On-line six-degree-of-freedom errors measurement and compensation for XY stages

CNC 레이저 가공기의 가공 정밀도 개선을 위한 입력성형 적용

This study presents an application of input shaping to a CNC laser processing machine to enhance performance. An effective command generation method is developed to reduce tracking errors and vibrations during the XY stage of laser processing. This study then conducts simulations with an analytical model of the stage in which anisotropic characteristics are considered. Simulation results revealed that two-mode input shapers should be employed during command generation to reduce tracking errors caused by input shaping. Experiments were successfully performed to show the enhanced processing quality with the CNC laser processing machine on two typical laser marking processes: linear marking and a combined process of linear and circular marking. The simulations and experiments showed that the proposed command generation method is very useful for improving the processing precision of the CNC laser processing machine.

Minimal Detection Time for Localization of Radioactive Hot Spots in Low and Elevated Background Environments Using a CZT Gamma-Ray Spectrometer

This study determines the minimal detection time (MDT) needed for successful localization of radioactive hot spots during nuclear decommissioning work. An automated XY stage, equipped with a CdZnTe (CZT) spectrometer, was used to identify and localize hot spots of 241Am, 137Cs, and 60Co in a 1.7 × 1.7-m area. The stage served as a preliminary test platform for the development of an automated robotic characterization platform [Autonomous Robotic platform for CHaractERization (ARCHER) robot]. The dependence of the MDT on the detector efficiency and background (BKG) level was examined. For low BKG environments, the MDT for 137Cs was 871 ms and resulted in an error of the source localization of 14.21 mm and an error of the activity of 6.85%. For elevated BKG levels, the MDT increased to 15 526 ms. The 137Cs source was localized with an error of 34.13 mm and an error of the source activity of −7.04%. The MDT determination method used here offers a valuable approach for decreasing total scanning times while avoiding missing the presence of hot spots.

Analysis of solid uranium particulates on cotton swipes with an automated microextraction-ICP-MS system.

An automated microextraction method coupled to an inductively coupled plasma - mass spectrometer (ICP-MS) was developed for the direct analysis of solid uranium particulates on the surface of cotton swipes. The microextraction probe extracts particulates from the sample surface, in a flowing solvent, and directs the removed analyte to an ICP-MS for isotopic determination. The automated system utilizes a mechanical XY stage that is software controlled with the capability of saving and returning to specific locations and a camera focused to the swipe surface for optimal viewing of the extracted locations (i.e., material present). Here, particulates (n = 135) were extracted and measured by ICP-MS, including 35 depleted uranyl nitrate hexahydrate (UN) (used for mass bias corrections), 50 uranyl fluoride (UO2F2), and 50 uranyl acetate (UAc) particulates. Blank extractions were performed on the cotton swipes between triplicate sample analyses. Between each swipe extraction, the probe was sent between two wells containing 10% and 5% HNO3 to clean the probe head and to eliminate any analyte carryover between particulates. The measured 235U/238U and 234U/238U isotope ratios for the UO2F2 particulates were 0.00725(8) and 0.000054(4), a percent relative difference (% RD) of -0.041% and -1.7% from the reference isotope ratios determined in-lab through multi-collector ICP-MS analysis of dissolved aliquots of the U material. The UAc samples had a measured 235U/238U isotope ratio of 0.00206(7), a -0.96% relative difference from the reference value of 0.00208(1). The 234U/238U and 236U/238U isotope ratios were 0.000008(1) and 0.000031(4), -5.1% RD and -4.3% RD, respectively. The automated sample stage enabled seamless and rapid particle analysis, leading to a significant increase in throughput versus what was previously possible. Additionally, the saved location capability reduced user sampling error as sampling locations were easily stored and recalled. Analysis of U particles on the swipe surface - including blanks, mass bias, and triplicate extractions - was completed in less than an hour without any sample preparation necessary.

Software compensation of undesirable racking motion of H-frame 3D printers using filtered B-splines

The H-frame (also known as H-Bot) architecture is a simple and elegant two-axis parallel positioning system used to construct the XY stage of 3D printers. It holds potential for high speed and excellent dynamic performance due to the use of frame-mounted motors that reduce the moving mass of the printer while allowing for the use of (heavy) higher torque motors. However, the H-frame's dynamic accuracy is limited during high-acceleration and high-speed motion due to racking -- i.e., parasitic torsional motions of the printer's gantry due to a force couple. Mechanical solutions to the racking problem are either costly or detract from the simplicity of the H-frame. In this paper, we introduce a feedforward software compensation algorithm, based on the filtered B-splines (FBS) method, that rectifies errors due to racking. The FBS approach expresses the motion command to the machine as a linear combination of B-splines. The B-splines are filtered through an identified model of the machine dynamics and the control points of the B-spline based motion command are optimized such that the tracking error is minimized. To compensate racking using the FBS algorithm, an accurate frequency response function of the racking motion is obtained and coupled to the H-frame's x- and y-axis dynamics with a kinematic model. The result is a coupled linear parameter varying model of the H-frame that is utilized in the FBS framework to compensate racking. An approximation of the proposed racking compensation algorithm, that decouples the x- and y-axis compensation, is developed to significantly improve its computational efficiency with almost no loss of compensation accuracy. Experiments on an H-frame 3D printer demonstrate a 43 percent improvement in the shape accuracy of a printed part using the proposed algorithm compared to the standard FBS approach without racking compensation.

Optimisation of Operational Parameters in Atmospheric Plasma Deposition

Nowadays additive manufacturing and 3D printing techniques are transferring in the mainstream industrial use. To compete for the share of the pie in this sector, atmospheric plasma can be used for deposition of material. In this work it will be presented the atmospheric plasma deposition of copper nanoparticles and the influence of the plasma operational parameters on the shape of the deposited copper line: the with and the density. The nanoparticles were produced by a facile aqueous-based seed-mediated chemical reduction method from copper nitrate hemi(pentahydrate), as described in article by Ankireddy et al. 1 The copper nanoparticles had bimodal size distribution with mean diameters of 3.6 and 64.6 nm. The nanoparticles were then dispersed in deionised water, caped with citric acid and used as a source for atmospheric plasma deposition. The plasma system comprised from nebuliser, nozzle and kHz power supply, as in the work of Gandhiraman et al. 2 During the plasma deposition of the particles the substrate was moving by XY step-motor stage. Parameters, that could be set and influenced the deposition were: gas mixture (different ratios of Ar and He gas flows), gas flow-rate, distance of the substrate from the plasma, plasma power, time between steps of XY stage and the number of passes/repetitions by XY stage. Different permutations of the parameters were used for the plasma deposition to determine the best parameter set for a dense deposition of a narrow line.In figure it can be seen two depositions with different parameters. The difference is obvious.[1] „Seed Mediated Copper Nanoparticle Synthesis for Fabricating Oxidation Free Interdigitated Electrodes using Intense Pulse Light Sintering for Flexible Printed Chemical Sensors“; Krishnamraju Ankireddy, Thad Druffel, Swathi Vunnam, Gregor Filipič, Ruvini Dharmadasa, Delaina A. Amos; Journal of Materials Chemistry C, 5 (2017), 11128 – 11137[2] „Plasma jet based in situ reduction of copper oxide in direct write printing“; Avishek Dey, Arlene Lopez, Gregor Filipič, Aditya Jayan, Dennis Nordlund, Jessica Koehne, Satheesh Krishnamurthy, Ram P. Gandhiraman, M. Meyyappan; Journal of Vacuum Science & Technology B, 37 (2019), 031203 Figure 1

A novel compliant XY micro-positioning stage using bridge-type displacement amplifier embedded with Scott-Russell mechanism

This paper presents a new bridge-type compliant displacement amplifier embedded with Scott-Russell mechanism. Based on this design, a novel compliant XY micro-positioning stage is also designed, analyzed and tested to illustrate the advantages of the proposed amplifier. The main feature of the new amplifier is to employ Scott-Russell mechanism to replace one arm of the compound bridge-type mechanism, aiming to improve its lateral stiffness and the natural frequency in the working direction. The compliant XY micro-positioning stage is driven by two novel bridge-type amplifiers with orthogonal distribution. Double parallelogram guide mechanisms are added at the output ends of the bridge-type mechanisms to further lower the parasitic movements of the XY stage. Then, an analytical model based on the stiffness matrix transfer method is established for the static and dynamic characteristics of stage, which are also verified by performing finite element analysis. Finally, an experimental prototype is manufactured and its static and dynamic performances are tested. The test results demonstrate that the stage can realize a workspace of 181.0 μm × 179.5 μm with motion resolution of 20 nm and a maximum coupling error of 1.07%. The natural frequencies of XY stage along the working direction are 178 Hz and 248 Hz respectively when the PZTs are not installed or installed. Additionally, the trajectory tracking performance of the stage is also preliminarily evaluated. All of the results obtained from the analytical model, finite element analysis and experimental tests verify the effectiveness of the novel bridge-type displacement amplifier and the compliant XY micro-positioning stage.

An Open-Source Framework for Automated High-Throughput Cell Biology Experiments.

Modern data analysis methods, such as optimization algorithms or deep learning have been successfully applied to a number of biotechnological and medical questions. For these methods to be efficient, a large number of high-quality and reproducible experiments needs to be conducted, requiring a high degree of automation. Here, we present an open-source hardware and low-cost framework that allows for automatic high-throughput generation of large amounts of cell biology data. Our design consists of an epifluorescent microscope with automated XY stage for moving a multiwell plate containing cells and a perfusion manifold allowing programmed application of up to eight different solutions. Our system is very flexible and can be adapted easily for individual experimental needs. To demonstrate the utility of the system, we have used it to perform high-throughput Ca2+ imaging and large-scale fluorescent labeling experiments.

Design of a flexure-based parallel XY micropositioning stage with millimeter workspace and high bandwidth

This paper presents the design of a flexure-based parallel XY micropositioning stage with millimeter workspace and high bandwidth. The large range micropositioning requires the workspace of flexure-based stage to reach millimeter level. Meanwhile, the structural bandwidth of the flexure-based stage with large range is relatively low, which limits the scan rate and is required to be improved. A novel parallel mechanism is implemented to improve the structural bandwidth of the millimeter level flexure-based XY stage by removing redundant mass. The coupling between the working axes is reduced by a decoupler based on circular hinges. The mechanical performances of the designed XY stage are analyzed by theoretical models and verified by finite element analysis (FEA). Experimental results indicate that the designed XY micropositioning stage is capable of achieving millimeter workspace as well as a relatively high resonance frequency compared with other millimeter level flexure-based XY stages.

Platform Incubator with Movable XY Stage: A New Platform for Implementing In-Cell Fast Photochemical Oxidation of Proteins

Fast Photochemical Oxidation of proteins (FPOP) coupled with mass spectrometry (MS) has become an invaluable tool in structural proteomics to interrogate protein interactions, structure, and protein conformational dynamics as a function of solvent accessibility. In recent years, the scope of FPOP, a hydroxyl radical protein foot printing (HRPF) technique, has been expanded to protein labeling in live cell cultures, providing the means to study protein interactions in the convoluted cellular environment. In-cell protein modifications can provide insight into ligand induced structural changes or conformational changes accompanying protein complex formation, all within the cellular context. Protein footprinting has been accomplished employing a customary flow-based system and a 248 nm KrF excimer laser to yield hydroxyl radicals via photolysis of hydrogen peroxide, requiring 20 minutes of analysis for one cell sample.To facilitate time-resolved FPOP experiments, the use of a new 6-well plate-based IC-FPOP platform was pioneered. In the current system, a single laser pulse irradiates one entire well, which truncates the FPOP experimental time frame resulting in 20 seconds of analysis time, a 60-fold decrease. This greatly reduced analysis time makes it possible to research cellular mechanisms such as biochemical signaling cascades, protein folding, and differential experiments (i.e., drug-free vs. drug bound) in a time-dependent manner. This new instrumentation, entitled Platform Incubator with Movable XY Stage (PIXY), allows the user to perform cell culture and IC-FPOP directly on the optical bench using a platform incubator with temperature, CO2 and humidity control. The platform also includes a positioning stage, peristaltic pumps, and mirror optics for laser beam guidance. IC-FPOP conditions such as optics configuration, flow rates, transient transfections, and H2O2 concentration in PIXY have been optimized and peer-reviewed. Automation of all components of the system will reduce human manipulation and increase throughput.

Platform Incubator with Movable XY Stage: A New Platform for Implementing In-Cell Fast Photochemical Oxidation of Proteins.

Fast Photochemical Oxidation of proteins (FPOP) coupled with mass spectrometry (MS) has become an invaluable tool in structural proteomics to interrogate protein interactions, structure, and protein conformational dynamics as a function of solvent accessibility. In recent years, the scope of FPOP, a hydroxyl radical protein foot printing (HRPF) technique, has been expanded to protein labeling in live cell cultures, providing the means to study protein interactions in the convoluted cellular environment. In-cell protein modifications can provide insight into ligand induced structural changes or conformational changes accompanying protein complex formation, all within the cellular context. Protein footprinting has been accomplished employing a customary flow-based system and a 248 nm KrF excimer laser to yield hydroxyl radicals via photolysis of hydrogen peroxide, requiring 20 minutes of analysis for one cell sample.To facilitate time-resolved FPOP experiments, the use of a new 6-well plate-based IC-FPOP platform was pioneered. In the current system, a single laser pulse irradiates one entire well, which truncates the FPOP experimental time frame resulting in 20 seconds of analysis time, a 60-fold decrease. This greatly reduced analysis time makes it possible to research cellular mechanisms such as biochemical signaling cascades, protein folding, and differential experiments (i.e., drug-free vs. drug bound) in a time-dependent manner. This new instrumentation, entitled Platform Incubator with Movable XY Stage (PIXY), allows the user to perform cell culture and IC-FPOP directly on the optical bench using a platform incubator with temperature, CO2 and humidity control. The platform also includes a positioning stage, peristaltic pumps, and mirror optics for laser beam guidance. IC-FPOP conditions such as optics configuration, flow rates, transient transfections, and H2O2 concentration in PIXY have been optimized and peer-reviewed. Automation of all components of the system will reduce human manipulation and increase throughput.

Investigations on piezo actuated micro XY stage for vibration-assisted micro milling

Vibration assisted machining is an advanced non-conventional precision machining technique aiming at improving the machining performance by superimposing a small amplitude, high-frequency vibration either on the tool or on the workpiece. This article presents the mechanical design, electromechanical simulation, and experimentation on the developed prototype of the flexural hinged micro XY stage for the vibration-assisted micro-milling system. The micro XY stage comprises three layers of flexural hinge structure surrounding the central parallel kinematic structure. The finite element analysis method is adopted to evaluate the static structural stiffness and harmonic behaviour. Two multilayer piezoelectric stack actuators drive the micro XY stage in X and Y directions. The experimental results show that the micro XY stage has a vibrating work area of 17.06 µm × 17.11 µm with a hysteresis nonlinearity and cross-coupling displacements on both axes. Therefore, an electromechanical model is essential to compensate for the hysteresis behaviour and cross-coupling displacements. Open-loop tracking control experiments determine the accuracy of the developed electromechanical model. Implementing a combined hysteresis and cross-coupling displacement compensation approach into the electromechanical model resulted in an open-loop tracking error of 7% for the synchronised circular path and a maximum deviation of 0.6 µm from the linear path.