Rapid Alignment Research Articles

Developing an Online Interactive Volumetric Surface Viewer for Visualizing Spatial Distribution of Intracranial Lesions.

The exact location of intracranial neoplasms and metastatic lesions within the cortex may provide key insights into predicting treatment effectiveness and toxicities. Modern neuroimaging approaches have enabled precise, rapid diffeomorphic alignment from individual brains to an atlas, allowing the registration of contours and dose distributions onto a common template. However, there is a paucity of intuitive tools to perform such functions. Here, we developed an online interactive volumetric surface viewer that displays distribution of brain lesions of specific clinical features within the context of prior radiation treatment in populations of patients on a common atlas. Data from 647 patients treated at our institution with radiotherapy for intracranial lesions were analyzed with FreeSurfer to perform intensity normalization, skull-stripping, and affine registration to Talairach coordinates. A custom-built VoxelMorph model was trained to register T1 MRIs to a common atlas. Radiation dose maps and contours on underlying CT simulation scans were rigidly aligned to the T1 MRIs. The diffeomorphic warps were then applied to the radiation dose maps and contours, including the gross tumor volumes. Surface rendering of the template atlas was performed using FreeSurfer and visualized using PyCortex. Clinical information including primary sites for brain metastases, lesion size, survival, recurrence, use of anti-epileptic medications, radiation necrosis, and neuro-cognitive toxicity was embedded into the PyCortex viewer. The custom-trained VoxelMorph model enabled rapid normalization of the T1MRIs to the atlas brain. PyCortex allows for interactive visualization of the spatial distribution of lesions on the cortical surface across a rich array of clinical parameters. Initial maps have qualitatively revealed a predilection for metastases in the right hemisphere. This WebGL viewer allows intuitive clinical interrogation on a visual surface enabling population inferences. For example, one can visualize the distribution of brain metastases of a large patient cohort based on their primary tumor sites, propensity for seizure and risk for radionecrosis. We successfully built an online interactive viewer to visualize the spatial distribution of intracranial lesions on a common reference. Our approach extends prior work allowing visual interaction of lesions and real-time generation of inference maps by combining a front-end viewer and back-end database of clinical data. This viewer may represent a critical step towards uncovering the location-dependent breakdown of the blood-brain-barrier, differentiating the propensity of primary lesions metastasizing to brain regions, and allowing the discovery of associations of previously understudied spatial neighborhoods. We plan to release a publicly available web-based viewer to further explore, interrogate, and inform future radiation treatments.

Resonant dynamical friction around a supermassive black hole: analytical description

ABSTRACT We derive an analytical model for the so-called phenomenon of resonant dynamical friction, where a disc of stars around a supermassive black hole interacts with a massive perturber, so as to align its inclination with the disc’s orientation. We show that it stems from a singular behaviour of the orbit-averaged equations of motion, which leads to a rapid alignment of the argument of the ascending node Ω of each of the disc stars, with that of the perturber, Ωp, with a phase difference of 90°. This phenomenon occurs for all stars whose maximum possible $\dot{\Omega }$ (maximized over all values of Ω for all the disc stars) is greater than $\dot{\Omega }_{\rm p}$; this corresponds approximately to all stars whose semi-major axes are less than twice that of the perturber. The rate at which the perturber’s inclination decreases with time is proportional to its mass and is shown to be much faster than Chandrasekhar’s dynamical friction. We find that the total alignment time is inversely proportional to the root of the perturber’s mass. This persists until the perturber enters the disc. The predictions of this model agree with a suite of numerical N-body simulations, which we perform to explore this phenomenon, for a wide range of initial conditions, masses, etc., and are an instance of a general phenomenon. Similar effects could occur in the context of planetary systems, too.

Effect of temperature on the dipole response, structural and dynamical properties of water under external electric fields

Water, as simultaneously the most intriguing and ubiquitous liquid on the planet, holds central relevance in our world – and displays a suite of fascinating anomalies. Of notable interest in this study is the leveraging of non-equilibrium molecular dynamics (NEMD) simulation to study the response of water molecules under the influence of external electric-fields while subjected to temperature changes. In particular, external static and oscillating electric fields with varying (r.m.s) intensities 0.05V/Å and 0.10V/Å and oscillating-field frequencies 50, 100 and 200GHz were examined to gauge the influence of supercooled and nearer-ambient temperature regions on water structure and interaction, dynamical properties, dipolar response, hydrogen-bond kinetics and lifetime. Interestingly, the impact of heating the system was accentuated with increase in the hydrogen-bond lengths, and A–D–H angles while the number of hydrogen-bonds reduced with increase in the temperature for all the fields conditions, although slight variations were observed under the influence of static and oscillating fields. Furthermore, as temperature increases, the increased rate of hydrogen-bond breakage influenced the rapid decay of hydrogen-bond lifetimes for zero- and static-field conditions, while molecular rotations caused by dipole-alignment response to the oscillating fields enhanced to a greater extent the mobility of the molecules, and also increased the rate of hydrogen-bond breakage and diffusivity due to the increased thermal motion. Moreover, the effect of increasing the temperature on the polarisation properties of the liquid weakened the hydrogen-bond network and also led to a decrease in the molecular and time response of the system’s dipole moment; higher temperature and field intensity invoked more rapid system dipolar alignment, in addition to the frequency relating to longer periods and greater intensity. With increasing temperature, the behaviour of system dynamics revealed shorter correlation times for zero-field conditions while oscillating-field with increased intensity revealed more rapid autocorrelation decay in comparison to those with reduced intensity. Indeed, the presence of much longer correlation time manifested by zero-field conditions in the supercooled temperature region evinced succinctly the lack of rotational motion that allows for more rapid decay time.

Spontaneous Orthogonal Alignment of Smooth Muscle Cells and Endothelial Cells Captures Native Blood Vessel Morphology in Tissue-Engineered Vascular Grafts.

Tissue-engineered vascular grafts (TEVGs) have emerged as a potential alternative to autologous grafts for replacing small-diameter blood vessels during bypass surgery. The axial alignment of endothelial cells (ECs) and the circumferential alignment of smooth muscle cells (SMCs) are crucial for functional native blood vessels (NBVs). However, achieving this cellular alignment in TEVGs remains a formidable challenge. In this study, TEVGs were developed using a low-cost technique that aligned ECs axially and SMCs circumferentially within hours. The TEVGs comprised an electrospun polycaprolactone (PCL) layer and a gelatin methacryloyl (GelMA) cast layer. A freezing-induced alignment technique was developed that partially aligns the electrospun fibers axially, thereby promoting rapid axial alignment of ECs. Furthermore, SMCs cultured in a GelMA layer with intermediate stiffness (5-12 kPa) surrounding a PCL tube could promote conformation of the SMCs to the curvature of the PCL tube, resulting in their spontaneous circumferential alignment. Additionally, the TEVGs demonstrated mechanical properties similar to those of NBVs, which could facilitate future translation. This approach represents a significant advance in tissue engineering, enabling the fabrication of TEVGs with appropriate mechanical properties that recapitulate key NBV cell structural features within hours using a scalable and accessible method.

Rapid and Accurate INS Transfer Alignment for Air Launched Tactical Missile Using Kalman Filter

An Inertial Navigation System (INS) independently measures the Position, Velocity, and Attitude (PVA) of thevehicle to navigate it towards the target. Since INS is a dead-reckoning system, it requires accurate initialization toprovide the navigation (PVA) solution. In the case of an air-launched tactical missile, the aircraft navigation system(Master INS) information is used to initialize accurately the missile INS (Slave INS). Rapid transfer alignment isneeded in today’s combat operation to converge slave INS initialization in the shortest possible time using aircraftnavigation information. The transfer alignment consists of first initializing the missile INS and establishing anavigation solution (PVA) using the missile IMU rates and accelerations, then a Kalman filter is used to, estimatethe errors between the Slave INS and Master INS. The proposed method’s simulation results show that a tacticalmissile INS can be aligned to an acceptable accuracy in a very short time based on the aircraft’s attitude information and with natural maneuvers experienced during aircraft take-off.

Research on Integrated 3D Printing of Microfluidic Chips.

Microfluidic chips have the advantages of miniaturization, integration, and portability, and are widely used in the early diagnosis of major diseases, personalized medical treatment, environmental detection, health quarantine, and other fields. The existing microfluidic chip manufacturing process is difficult to operate because of complex three-dimensional channels, complicated manufacturing steps, limited printing materials, the difficulty of operating the bonding process, and the need to purchase expensive new equipment. In this paper, an integrated molding method for microfluidic chips that integrates 3D printing and polymer dissolution technology is proposed. First, the channel mold of poly(vinyl alcohol) (PVA) or high impact polystyrene (HIPS) is dissolved to complete the manufacturing of the microfluidic chip channel. The integrated 3D-forming method of microfluidic chips proposed in this paper can manufacture microchannels inside the microfluidic chip, avoid the bonding process, and eliminate the need for rapid alignment of microchannels, material modification, and other operations, thus improving the stability of the process. Finally, by comparing the microchannels made by PVA and HIPS, it is concluded that the quality of the microchannels made by HIPS is obviously better than that made by PVA. This paper provides a new idea for the fabrication of microfluidic chips and the application of HIPS.

A novel adaptive nonlinear Kalman filter scheme for DVL-aided SINS alignment in underwater vehicles

The rapid and accurate initial alignment of a strapdown inertial navigation system (SINS) aided by a Doppler velocity logger (DVL) still poses a significant challenge in unmanned underwater vehicle navigation. In this study, a novel adaptive nonlinear filtering alignment scheme is developed for a SINS with a large misalignment angle. In previous studies, the frame-inconsistency problem of the nonlinear SINS error model was neglected. Thus, a modified nonlinear error model of a SINS is derived here rigorously as the process model of the nonlinear Kalman filter. In addition, the noise amplification of applying Sage-Husa adaptive Kalman filter (SHAKF) in alignment is analyzed, and a novel arctangent fading memorial factor is introduced to dynamically adjust the weight of current measurements. Simulations and field experiments indicate that the proposed algorithm is efficient in underwater DVL/SINS in-motion alignment. The alignment accuracy and convergence rate of the modified model are significantly improved compared to those of the traditional model. The arctangent fading memorial SHAKF can reliably estimate the measurement noise and improve the performance of alignment.

Tissue Microarray Lipidomic Imaging Mass Spectrometry Method: Application to the Study of Alcohol-Related White Matter Neurodegeneration.

Central nervous system (CNS) white matter pathologies accompany many diseases across the lifespan, yet their biochemical bases, mechanisms, and consequences have remained poorly understood due to the complexity of myelin lipid-based research. However, recent advances in matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS) have minimized or eliminated many technical challenges that previously limited progress in CNS disease-based lipidomic research. MALDI-IMS can be used for lipid identification, semi-quantification, and the refined interpretation of histopathology. The present work illustrates the use of tissue micro-arrays (TMAs) for MALDI-IMS analysis of frontal lobe white matter biochemical lipidomic pathology in an experimental rat model of chronic ethanol feeding. The use of TMAs combines workload efficiency with the robustness and uniformity of data acquisition. The methods described for generating TMAs enable simultaneous comparisons of lipid profiles across multiple samples under identical conditions. With the methods described, we demonstrate significant reductions in phosphatidylinositol and increases in phosphatidylcholine in the frontal white matter of chronic ethanol-fed rats. Together with the use of a novel rapid peak alignment protocol, this approach facilitates reliable inter- and intra-group comparisons of MALDI-IMS data from experimental models and could be extended to human disease states, including using archival specimens.

Plasmodium knowlesi circumsporozoite protein: genetic characterisation and predicted antigenicity of the central repeat region.

Circumsporozoite protein (CSP) central repeat region is one of the main target regions of the RTS,S/AS01 vaccine for falciparum infection as it consists of immunodominant B cell epitopes. However, there is a lack of study for P. knowlesi CSP central repeat region. This study aims to characterise the CSP repeat motifs of P. knowlesi isolates in Peninsular Malaysia. CSP repeat motifs of 64 P. knowlesi isolates were identified using Rapid Automatic Detection and Alignment of Repeats (RADAR). Antigenicity of the repeat motifs and linear B cell epitopes were predicted using VaxiJen 2.0, BepiPred-2.0 and BCPred, respectively. A total of 35 dominant repeat motifs were identified. The repeat motif "AGQPQAQGDGANAGQPQAQGDGAN" has the highest repeat frequency (n=15) and antigenicity index of 1.7986. All the repeat regions were predicted as B cell epitopes. In silico approaches revealed that all repeat motifs were antigenic and consisted of B cell epitopes which could be designed as knowlesi malaria vaccine.

Protein remote homology recognition using local and global structural sequence alignment

Protein Remote Homology and fold Recognition (PRHR) is the most crucial task to predict the protein patterns. To achieve this task, Sequence-Order Frequency Matrix-Sampling and Deep learning with Smith-Waterman (SOFM-SDSW) were designed using large-scale Protein Sequences (PSs), which take more time to determine the high-dimensional attributes. Also, it was ineffective since the SW was only applied for local alignment, which cannot find the most matches between the PSs. Hence, in this manuscript, a rapid semi-global alignment algorithm called SOFM-SD-GlobalSW (SOFM-SDGSW) is proposed that facilitates the affine-gap scoring and uses sequence similarity to align the PSs. The major aim of this paper is to enhance the alignment of SW algorithm in both locally and globally for PRHR. In this algorithm, the Maximal Exact Matches (MEMs) are initially obtained by the bit-level parallelism rather than to align the individual characters. After that, a subgroup of MEMs is obtained to determine the global Alignment Score (AS) using the new adaptive programming scheme. Also, the SW local alignment scheme is used to determine the local AS. Then, both local and global ASs are combined to produce a final AS. Further, this resultant AS is considered to train the Support Vector Machine (SVM) classifier to recognize the PRH and folds. Finally, the test results reveal the SOFM-SDGSW algorithm on SCOP 1.53, SCOP 1.67 and Superfamily databases attains an ROC of 0.97, 0.941 and 0.938, respectively, as well as, an ROC50 of 0.819, 0.846 and 0.86, respectively compared to the conventional PRHR algorithms.

An Unsupervised Rapid Network Alignment Framework via Network Coarsening

Network alignment aims to identify the correspondence of nodes between two or more networks. It is the cornerstone of many network mining tasks, such as cross-platform recommendation and cross-network data aggregation. Recently, with the development of network representation learning techniques, researchers have proposed many embedding-based network alignment methods. The effect is better than traditional methods. However, several issues and challenges remain for network alignment tasks, such as lack of labeled data, mapping across network embedding spaces, and computational efficiency. Based on the graph neural network (GNN), we propose the URNA (unsupervised rapid network alignment) framework to achieve an effective balance between accuracy and efficiency. There are two phases: model training and network alignment. We exploit coarse networks to accelerate the training of GNN after first compressing the original networks into small networks. We also use parameter sharing to guarantee the consistency of embedding spaces and an unsupervised loss function to update the parameters. In the network alignment phase, we first use a once-pass forward propagation to learn node embeddings of original networks, and then we use multi-order embeddings from the outputs of all convolutional layers to calculate the similarity of nodes between the two networks via vector inner product for alignment. Experimental results on real-world datasets show that the proposed method can significantly reduce running time and memory requirements while guaranteeing alignment performance.

Rapid Transfer Alignment for Large and Time-Varying Attitude Misalignment Angles

Transfer alignment is an effective method to estimate the attitude difference between two inertial platforms. Traditional transfer alignment methods are either meant for small misalignments or use nonlinear filtering. Linear methods for large misalignments use quaternion attitude representation, but their performance degrades when the misalignment is not constant or slowly varying. This work proposes applying rapid transfer alignment to the inertial stabilization of a Satcom On-The-Move antenna. In this application case, the two inertial platforms are connected by a kinematic chain, meaning the attitude difference between the inertial platforms is both large and time-varying. This work proposes a method to estimate this attitude difference, with a Kalman filter used for the estimation of the unknown angles. To that effect, a new propagation model is developed to take into account the misalignment variations using master and slave rotation rates. Simulation results show the performance of the proposed solution in a Satcom antenna inertial stabilization case.

경사 발사 유도무기체계에서 함상 저장 전달정렬 가능성 연구

Shipboard transfer alignment is a procedure for determining the initial navigation information of the ship-mounted guided weapon system’s SINS by receiving the surface ship INS information. In order to improve the navigation accuracy of the ship-launched guided missile system, it is necessary to enhance the precision and accuracy of the shipboard transfer alignment. Generally, the shipboard transfer alignment uses both velocity matching and attitude matching to increase observability. Estimating the misalignment error between SINS and MINS using an extended Kalman filter is necessary to obtain the initial attitude of SINS in shipboard transfer alignment to which attitude matching is applied. Because it takes several minutes for the estimated misalignment error to converge, it is essential to reduce the alignment time, especially in the case of weapon systems. This paper presents the possibility of utilizing the shipboard stored transfer alignment for navigation-grade INS mounted on the inclined launching system. There have been no reports of previous studies on the shipboard stored transfer alignment. In a similar research case, a rapid initial alignment method using the pre-performed alignment results was proposed to reduce the alignment time of tactical-grade INS, which was mounted on the launch platform with MINS. To verify the possibility of the shipboard stored transfer alignment, the existing shipboard transfer alignment was repeatedly performed using an inclined guided missile system deployed in the military. The results show that the repeatability and accuracy of the misalignment error satisfy the initial attitude error requirement. Therefore, based on the test results, it is verified that the shipboard stored transfer alignment for the inclined launching guided missile equipped with a navigation-grade INS is possible.

Managing Through a Pandemic: A Daily Management System for COVID-19 Response and Recovery.

This study explored the use of a Lean daily management system (DMS) for COVID-19 response and recovery in U.S. hospitals and health systems. Originally developed in manufacturing, Lean is an evidence-based approach to quality and process improvement in healthcare. Although Lean has been studied in individual hospital units and outpatient practices, it has not been examined as a whole system response to crisis events. We conducted qualitative interviews with 46 executive leaders, clinical leaders, and frontline staff in four hospitals and health systems across the United States. We developed a semistructured interview guide to understand DMS implementation in these care delivery organizations. As interviews took place 6-8 months following the onset of the pandemic, a subset of our interview questions centered on DMS use to meet the demands of COVID-19. Based on a deductive approach to qualitative analysis, we identified clusters of themes that described how DMS facilitated rapid system response to the public health emergency. There were many important ways in which U.S. hospitals and health systems leveraged their DMS to address COVID-19 challenges. These included the use of tiered huddles to facilitate rapid communication, the creation of standard work for redeployed staff, and structured problem-solving to prioritize new areas for improvement. We also discovered ways that the pandemic itself affected DMS implementation in all organizations. COVID-19 universally created greater DMS visibility by opening lines of communication among leadership, strengthening measurement and accountability, and empowering staff to develop solutions at the front lines. Many lessons learned using DMS for crisis management will carry forward into COVID-19 recovery efforts. Lessons include expanding telehealth, reactivating incident command systems as needed, and efficiently coordinating resources amid potential future shortages. Overall, the Lean DMS functioned as a robust property that enabled quick organizational response to unpredictable events. Our findings on the use of DMS are consistent with organizational resilience that emphasizes collective sense-making and awareness of incident status, team decision-making, and frequent interaction and coordination. These features of resilience are supported by DMS practices such as tiered huddles for rapid information dissemination and alignment across organizational hierarchies. When used in conjunction with plan-do-study-act methodology, huddles provide teams with enhanced feedback that strengthens their ability to make changes as needed. Moreover, gaps between work-as-imagined (how work should be done) and work-as-done (how work is actually done) may be exacerbated in the initial chaos of emergency events but can be minimized through the development of standard work protocols. As a facilitator of resilience, the Lean DMS may be used in a variety of challenging situations to ensure high standards of care.

A Fast North-Finding Algorithm on the Moving Pedestal Based on the Technology of Extended State Observer (ESO).

We propose a kind of fast and high-precision alignment algorithm based on the ESO technology. Firstly, in order to solve the problems of rapid, high-accuracy, and anti-interference alignment on the moving pedestal in the north-seeker, the ESO technology in control theory is introduced to improve the traditional Kalman fine-alignment model. This method includes two stages: the coarse alignment in the inertial frame and fine alignment based on the ESO technology. By utilizing the ESO technology, the convergence speed of the heading angle can be greatly accelerated. The advantages of this method are high-accuracy, fast-convergence, strong ability of anti-interference, and short time-cost (no need of KF recursive calculation). Then, the algorithm model, calculation process, and the setting initial-values of the filter are shown. Finally, taking the shipborne north-finder based on the FOG (fiber-optic gyroscope) as the investigated subject, the test on the moving ship is carried out. The results of first off-line simulation show that the misalignment angle of the heading angle of the proposed (traditional) method is ≤2.1′ (1.8′) after 5.5 (10) minutes of alignment. The results of second off-line simulation indicate that the misalignment angle of the heading angle of the proposed (traditional) method is ≤4.8′ (14.2′) after 5.5 (10) minutes of alignment. The simulations are based on the ship-running experimental data. The measurement precisions of Doppler velocity log (DVL) are different in these two experiments.

Fast Local Alignment of Protein Pockets (FLAPP): A System-Compiled Program for Large-Scale Binding Site Alignment

Protein function is a direct consequence of its sequence, structure, and the arrangement at the binding site. Bioinformatics using sequence analysis is typically used to gain a first insight into protein function. Protein structures, on the other hand, provide a higher resolution platform into understanding functions. As the protein structural information is increasingly becoming available through experimental structure determination and through advances in computational methods for structure prediction, the opportunity to utilize these data is also increasing. Structural analysis of small molecule ligand binding sites in particular provides a direct and more accurate window to infer protein function. However, it remains a poorly utilized resource due to the huge computational cost of existing methods that make large-scale structural comparisons of binding sites prohibitive. Here, we present an algorithm called FLAPP that produces very rapid atomic level alignments. By combining clique matching in graphs and the power of modern CPU architectures, FLAPP aligns a typical pair of binding sites at ∼12.5 ms using a single CPU core, ∼1 ms using 12 cores on a standard desktop machine, and performs a PDB-wide scan in 1-2 min. We perform rigorous validation of the algorithm at multiple levels of complexity and show that FLAPP provides accurate alignments. We also present a case study involving vitamin B12 binding sites to showcase the usefulness of FLAPP for performing an exhaustive alignment-based PDB-wide scan. We expect that this tool will be invaluable to the scientific community to quickly align millions of site pairs on a normal desktop machine to gain insights into protein function and drug discovery for drug target and off-target identification and polypharmacology.

A New Polar Rapid Transfer Alignment Method Based on Grid Frame for Shipborne SINS

A polar grid rapid transfer alignment method for shipborne strapdown inertial navigation system (SINS) is studied. The basic framework and the specific process of grid rapid transfer alignment are built. The grid equations of attitude error, velocity error and position error of SINS are deduced. The math model of alignment with velocity plus attitude quaternion method is established. The velocity plus attitude quaternion method and velocity plus attitude angle method are derived and compared. On this basis, the Kalman filter algorithm is used to design grid alignment filter. The ship trajectory is designed and generated, and the researched alignment method is simulated and verified by MATLAB. Simulation results show that the proposed method can accurately estimate the attitude error angle, velocity error, deflection deformation angle and installation error angle, except at the poles, whether in mid latitude or high latitude, and regardless of the sea state level. The horizontal estimation accuracy of attitude error angle is 0.8’, the azimuth estimation accuracy is within 1.8’, the velocity error is within 0.03m/s, and the estimation accuracy of deflection angle and installation error angle is within 1.2’. Finally, the ship experiment is carried out, and the experimental results show that the actual application effect of the proposed method was as satisfactory as in the simulation experiment. During the estimation time of 20 s, the attitude misalignment angle error is 0.2 ’, the velocity error is 0.05 m/s, and the estimation accuracy of deflection deformation angle and installation error angle is less than 1’.

Rapidly reprogrammable actuation of liquid crystal elastomers

A rapid and reprogrammable alignment strategy for the reversible actuation of liquid crystal elastomers has been achieved through the phase-transition-induced shape memory effect. This breakthrough, recently reported in <i>Advanced Materials</i> by Xie and colleagues, illustrated the important role of shape-memory-induced stress regulation in developing and improving functional polymer materials.

Self-calibration of micro-components based on manipulator guidance

Automatic alignment of micro-component position and posture is an important part of micro-assembly. A self-calibration method of micro-components based on a droplet manipulator is proposed. The shape of the operating surface of the droplet manipulator is changed according to the shape of the micro-component and a droplet of the corresponding shape is formed; the position and posture of the operating surface of the droplet manipulator is used as a guide to drive the rapid alignment through the recovery force of the liquid bridge to achieve self-calibration of the micro-component. The self-calibration principle and process are analyzed using rectangular and triangular micro-components as examples, and the effectiveness of the proposed method is demonstrated experimentally. The research and experimental results show that the self-calibration can be achieved by changing the shape parameters of the operating surface of manipulator and controlling the corresponding droplet form; the self-calibration of position and posture of micro-components with different shapes and sizes can be achieved by matching the operating surface shape of the droplet manipulator and the micro-components; the automatic calibration success rate is 100% under the condition that the contact surface of the micro-component is completely wetted.

A fast and accurate transfer alignment method without relying on the empirical model of angular deformation

AbstractThis paper, in allusion to the limitations of traditional transfer alignment methods based on the external measurement equipment or the empirical model of angular deformation, proposes a rapid and accurate transfer alignment method without relying on the empirical angular deformation model. Firstly, the relationship between the actual angular deformation and the angular velocities measured by the gyroscopes in the master and slave inertial navigation systems (INSs) is derived to roughly estimate the angular deformation. Secondly, according to the error characteristics of gyroscopes, the error model of angular deformation is established. Thirdly, expanding the angular deformation error instead of the installation error angle, flexure angle and flexure angle rate into the state vector, a low-order transfer alignment filtering model independent of the empirical angular deformation model is established. The proposed method not only gets rid of the dependence on an empirical angular deformation model, but also realises the rapid and accurate initial alignment of the slave INS without adding any external measurement equipment. The simulations and experiments evidence the validity of the proposed transfer alignment method.