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In this paper, we introduce quadratic and cubic polynomial enrichments of the classical Crouzeix–Raviart finite element, with the aim of constructing accurate approximations in such enriched elements. To achieve this goal, we respectively add three and seven weighted line integrals as enriched degrees of freedom. For each case, we present a necessary and sufficient condition under which these augmented elements are well-defined. For illustration purposes, we then use a general approach to define two-parameter families of admissible degrees of freedom. Additionally, we provide explicit expressions for the associated basis functions and subsequently introduce new quadratic and cubic approximation operators based on the proposed admissible elements. The efficiency of the enriched methods is compared with that of the triangular Crouzeix–Raviart element. As expected, the numerical results exhibit a significant improvement, confirming the effectiveness of the developed enrichment strategy. [ABSTRACT FROM AUTHOR]

Space robots are inseparable components of many space missions. However, capabilities of space robots with rigid manipulators are restricted in confronting with unknown and confined environments and situations require high safety. To overcome these defects, the potential of bio-inspired soft robots for space applications has recently been addressed in the literature. Dynamic modeling and control of soft manipulators are challenging due to their infinite degrees of freedom. In this paper, a general comprehensive three-dimensional dynamic modeling framework is developed for a floating soft manipulator-spacecraft system employing the Euler-Lagrange method. This framework derives the coupled equations of motion adapting the generalized Jacobian approach. Consequently, the opportunity of exploiting model-based control methods will be provided. In addition, the proposed model avoids numerical singularities once the bending angles are near zero. Furthermore, the generalized Jacobian matrix is defined for any arbitrary point of the soft manipulator essential for the contact dynamics. Eventually, to verify the proposed dynamic modeling procedure, the dynamic response of a floating soft manipulator-spacecraft system released from an initial configuration is investigated. Then, a sliding mode controller is designed for the floating soft manipulator to track the desired shape and compared to the proportional-derivative control scheme. The obtained results follow the physical principles and fulfill the control objective. • To overcome defects of usual rigid manipulators, soft space robots are concentrated. • A thorough 3D modeling frame is presented for soft manipulator-spacecraft systems. • Thorough dynamic modeling process is established using the Euler-Lagrange approach. • The generalized Jacobian matrix is derived for any optional point of the soft arm. • Application of the sliding mode control is proven for the soft space manipulator. [ABSTRACT FROM AUTHOR]

• Identifies factors affecting the workers' bargaining power. • Builds a composite index for the United States using the principal component analysis. • Analyses the relationship between this index and the wage share in the years 1960–2018. • Discusses the link between the workers' bargaining power and inflation. • Estimates the Phillips curve and explains why it has flattened over the last decades. This paper aims to construct a synthetic index of workers' bargaining power and investigate the relationship between it and inflation in the U.S. economy. As a first step, we identify the factors affecting the bargaining power of workers, referring to different groups of variables: labour market indicators; institutional indicators (e.g., collective bargaining coverage, union density); characteristics of the economy (e.g., degree of freedom for capital mobility, share of employment by sector). We then implement Principal Component Analysis (PCA) to assess the adequacy of the indicators and calculate the weights to aggregate the single indicators into a composite index. As a second step, we estimate the impact of our Bargaining Index on inflation by estimating an equation of the determinants of inflation. The composite index thus has a twofold use: it sheds light on the extent to which changes in the labour market in recent decades have weakened workers' bargaining power, and it can be used to test how the evolution of the wage bargaining system affects inflation. [ABSTRACT FROM AUTHOR]

The targeted placement of selected carbon nanotubes is associated with low throughput rates. Hence, this paper presents a novel stage design for the fully automatic assembly of carbon nanotube field-effect transistors (CNTFETs) via mechanical dry transfer. It constitutes the core module of an assembly machine for the precise deployment of nanotubes onto a prefabricated wafer. The mechanical dry transfer approach allows high level of carbon nanotube selectivity with the aim of enabling a high-volume fabrication of ultra-clean devices. The previous production rate of such ultra-clean devices is less than one per hour, which offers a high potential for improvement. The stage consists of a parallel kinematic mechanism (PKM) with 3 degrees of freedom ( X 2 Y 2 C 1 ) carrying two additional stacked axes ( Z 1 C 2 ). The PKM is suspended on a vacuum preloaded aerostatic bearing, voice coil motors (VCM) and flexure hinges. Together with a combination of high precision and resolution touch probe measurement systems close to its tool center point (TCP), high accuracy and low settling time can be achieved. Based on realistic manufacturing tolerances, a sensitivity analysis of the mechanism's pseudo rigid body model (PRBM) suggests a theoretical closed-loop error below 0. 15 μ m over the entire XY workspace of 20 mm × 2. 8 mm. Measurements of positioning motions show that the settling time can be decreased by the compensation of friction resistances inside the internal bearings of the VCMs. [Display omitted] • Parallel kinematic micromanipulator with novel axis configuration. • Non-monolithic flexure hinge/voice coil combination. • Sensitivity analysis for the accuracy assessment of the manipulator. • Significant reduction of overshoot and settling time. [ABSTRACT FROM AUTHOR]

In this paper, we present explicit expressions for conforming finite element function spaces, basis functions, and degrees of freedom on the pentatope (the 4-simplex) and tetrahedral prism elements. More generally, our objective is to construct high-order finite element function spaces that maintain conformity with infinite-dimensional spaces of a carefully chosen de Rham complex in four dimensions. This paper is a natural extension of the companion paper entitled "Conforming finite element function spaces in four dimensions, part I: Foundational principles and the tesseract" by Nigam and Williams (2024). In contrast to Part I, in this paper we focus on two of the most popular elements which do not possess a full tensor-product structure in all four coordinate directions. We note that these elements appear frequently in existing space-time finite element methods. In order to build our finite element spaces, we utilize powerful techniques from the recently developed 'Finite Element Exterior Calculus'. Subsequently, we translate our results into the well-known language of linear algebra (vectors and matrices) in order to facilitate implementation by scientists and engineers. [ABSTRACT FROM AUTHOR]

The stability, robustness, accuracy, and efficiency of space-time finite element methods crucially depend on the choice of approximation spaces for test and trial functions. This is especially true for high-order, mixed finite element methods which often must satisfy an inf-sup condition in order to ensure stability. With this in mind, the primary objective of this paper and a companion paper is to provide a wide range of explicitly stated, conforming, finite element spaces in four dimensions. In this paper, we construct explicit high-order conforming finite elements on 4-cubes (tesseracts); our construction uses tools from the recently developed 'Finite Element Exterior Calculus'. With a focus on practical implementation, we provide details including Piola-type transformations, and explicit expressions for the volumetric, facet, face, edge, and vertex degrees of freedom. In addition, we establish important theoretical properties, such as the exactness of the finite element sequences, and the unisolvence of the degrees of freedom. [ABSTRACT FROM AUTHOR]

• A comprehensive vertical dynamics model of the electric vehicle considering the integrated powertrain system is proposed. • The limitations of traditional vertical dynamics model of electric vehicle in the high frequency range are revealed. • The effects of mounting stiffness and damping on the vibration of chassis and integrated powertrain system are explored. • A multi-objective optimization model is designed to minimize the vibration of chassis and integrated powertrain system. Integrated powertrain system, mainly composed of driving motor and reducer, is one of the excitation sources to electric vehicle vibration but is limited in coupling with the vertical vehicle dynamic in the existing research, which restricts the reliability of dynamics investigation of vehicle and integrated powertrain system. This work proposes a novel vertical dynamic model of the electric vehicle considering the integrated powertrain system, enabling the way to access the coupled vibration among the chassis, unsprung mass, and integrated powertrain system. The road irregularity, unbalanced magnetic pull, and gear mesh excitation are developed and are further applied to the novel vehicle dynamic model with ten degrees of freedom (DOFs). Then, the dynamic response between the novel model and traditional one is compared. Further, the effects of the stiffness and damping of suspension and mounting on the vibration of chassis and integrated powertrain system are explored by numerical calculation. Finally, a multi-objective optimization model is proposed and is driven by the dragonfly algorithm to minimize the vibration of chassis and integrated powertrain system. The research results shown that there will be present the new complex dynamic characteristics with considering the excitation from the integrated powertrain system. The suspension and mounting parameters have the nonlinear effects on the vehicle vibration. And the system vibration can be globally optimized with the optimization algorithm. [ABSTRACT FROM AUTHOR]

Space robots have proven their ability to accomplish many space missions impossible or dangerous for the human. However, the conventional space robots suffer from the low adaptability, heavy structures, and the low safety. In this regard, the bio-inspired soft robots, composed of the soft material, have been emerged to overcome these shortcomings and to expand the space missions' diversity. The potential of soft robots for space applications has recently been investigated in the literature. Although the dynamic modeling and control of soft robotic arms are complicated due to their infinite degrees of freedom, soft manipulators are anticipated to provide the adaptive capture of targets, confined space operations, and the long-distance handling of space facilities. In this regard, a general novel dynamic modeling algorithm is presented here for soft space robotic manipulators (SSRM) in a specified orientation based on the generalized Jacobian method. The proposed algorithm could be employed for different numbers of soft manipulator constant-curvature elements and avoids numerical singularities using the Taylor expansion as well. In addition, the generalized Jacobian matrix is defined to compute the velocity of any arbitrary point on the soft manipulator for contact dynamics objectives. Accuracy of the proposed dynamic model has been verified via comparison to the simulation results of the existing fixed-base soft manipulators. Moreover, performance of the proposed model has been more investigated through two numerical simulation case studies. The first case verifies that the dynamic responses of the floating SSRM follows the physical principles. While the second one addresses the configuration tracking problem of the floating SSRM exposing a computed torque control scheme. The obtained results indicate the effectiveness of the presented dynamic modeling algorithm and the proposed control scheme. [ABSTRACT FROM AUTHOR]

Given a ground-set of elements and a family of subsets, the set covering problem consists in choosing a minimum number of elements such that each subset contains at least one of the chosen elements. This research focuses on the set covering polytope, which is the convex hull of integer solutions to the set covering problem. We investigate the connection between the study of the facets of the set covering polytope and tilting theory. This theory studies how inequalities can be rotated around their contact points with a polyhedron in order to obtain inequalities inducing higher dimensional faces. To study this connection, we introduce the concept of tilting vectors which characterize the degrees of freedom of rotation of an inequality. These vectors characterize facet-defining inequalities and can be used to tilt inequalities with a similar procedure to the one used for arbitrary polyhedra. Additionally, we demonstrate that the computational effort needed to tilt an inequality can be reduced when the inequality has many null coefficients. Finally, we use the tilting vectors to extend several necessary and/or sufficient conditions for facets of the set covering polytope presented by several previous works of the literature. [ABSTRACT FROM AUTHOR]

In the conventional two-grid (TG) method, the nonlinear system on the fine grid is transformed into a nonlinear subsystem on the coarse grid and a linear subsystem on the fine grid to reduce computational costs. It has been successfully applied in various fields. Nonetheless, its computational efficiency remains relatively low. For this, we develop a novel reduced-order two-grid (ROTG) method with less degrees of freedom for solving the semilinear parabolic equation. For the two subsystems mentioned, the proper orthogonal decomposition (POD) technique is utilized to substantially reduce degrees of freedom. An a priori error estimate for the ROTG scheme is derived. Finally, we conduct several numerical tests to observe the ROTG method's behavior and verify the theoretical analysis. [ABSTRACT FROM AUTHOR]

In this paper, we develop the Hermite-type virtual element method to solve the second order problem. A Hermite-type virtual element of degree ≥3 is constructed, which can be taken as an extension of classical Hermite finite element to polygonal meshes. For this virtual element, we rigorously prove some inverse inequalities and the boundedness of basis functions. Further, we prove the interpolation error estimates. Based on a computable H 1 -projection, we give the discrete formulation and prove the optimal convergence for the Hermite-type virtual element method. Finally, we show some numerical results to verify the convergence of Hermite-type virtual element. Additionally, compared with other virtual elements, both theoretical analysis and numerical experiments demonstrate that the Hermite-type virtual element has fewer global degrees of freedom and results in significant computational savings. [ABSTRACT FROM AUTHOR]

Ground-based full-scale physical experiments on spacecraft have become an essential part of ground simulations. However, achieving a vertical translational degree of freedom for zero-gravity simulation has become a key technological bottleneck for six-degree-of-freedom ground simulations. The combined active–passive vertical zero-gravity system discussed in this paper can achieve zero-gravity simulation in the vertical direction; however, it exhibits deficiencies such as inaccurate modeling, low control precision, and significant control delays. Addressing the issue of inaccurate modeling, this study uses interpretable ODE neural networks to identify the dynamic model of the system. For resolving the problems of poor control precision and significant delays, this study proposes a hybrid control algorithm based on the ODE dynamic model. The controller includes nominal model feedforward, PID feedback, and learning-based feedforward components. Finally, comparative experiments are designed to validate the proposed model-based hybrid control algorithm. Compared to PID-Feedforward controller, the hybrid controller exhibits a higher response speed, while compared to model-based feedforward controller, it exhibits a better control accuracy. Therefore, the proposed hybrid control algorithm based on the ODE dynamic model effectively enhances the control response speed and improves the control precision of the system. • A satellite simulator that realizes vertical zero-gravity simulation by combining active and passive methods. • Higher precision modeling of nonlinear dynamics by interpretable ODE neural networks. • Smaller control error compared with model-based feedforward controller, using model-based hybrid control algorithm. • Faster response speed compared with PID-Feedforward controller, using model-based hybrid control algorithm. [ABSTRACT FROM AUTHOR]

The present study proposes a novel approach for efficiently solving an anisotropic transient diffusion problem using an enriched finite element method. We develop directional enrichment for the finite elements in the spatial discretization and a fully implicit scheme for the temporal discretization of the governing equations. Within this comprehensive framework, the proposed class of exponential functions as enrichment enhance the approximation of the finite element method by capturing the directional based behaviour of the solution. The incorporation of these enrichment functions leverages a priori knowledge about the anisotropic problem using the partition of unity technique, resulting in significantly improved approximation efficiency while retaining all the advantages of the standard finite element method. Consequently, the proposed approach yields accurate numerical solutions even on coarse meshes and with significantly fewer degrees of freedom compared to the standard finite element methods. Moreover, the choice of mesh coarseness remains independent of the anisotropy in the problem, enabling the use of the same mesh regardless of changes in the anisotropy. Using extensive numerical experiments, we consistently demonstrate the efficiency of the proposed method in attaining the desired levels of accuracy. Our approach not only provides reliable and precise solutions but also extends the capabilities of the finite element method to effectively address aspects of the heterogeneous anisotropic transient diffusion problems that were previously considered ineffective when using this method. [ABSTRACT FROM AUTHOR]

Efficient solution strategies for wave propagation problems with complex geometries are essential in many engineering fields. Immersed boundary methods simplify mesh generation by embedding the domain of interest into an extended domain that is easy to mesh, introducing the challenge of dealing with cells that intersect the domain boundary. We consider the finite cell method that extends the weak form from the physical into the extended domain, multiplied by a small value, to stabilize badly cut cells. Combined with explicit time integration methods, the presence of finite cells with very little support in the physical domain results in tiny critical time step sizes. While the finite cell stabilization limits how small the critical time step size can become, this limit is still restrictive for many applications. Explicit transient analyses commonly use the spectral element method due to its natural way of obtaining diagonal mass matrices through nodal lumping. The resulting method is very efficient since nodal lumping renders the solution of the equation systems trivial while not reducing the accuracy or the critical time step size. The combination of the spectral element and finite cell methods is called the spectral cell method. Unfortunately, a direct application of nodal lumping in the spectral cell method is impossible due to the special quadrature necessary to treat the discontinuous integrand inside the cut cells. The existing approaches to lump the mass matrices of cut cells significantly reduce the accuracy of the approximation. We analyze an implicit-explicit (IMEX) time integration method to exploit the advantages of the nodal lumping scheme for uncut cells on one side and the unconditional stability of implicit time integration schemes for cut cells on the other. In this hybrid, immersed Newmark IMEX approach, we use explicit second-order central differences to integrate the uncut degrees of freedom that lead to a diagonal block in the mass matrix and an implicit trapezoidal Newmark method to integrate the remaining degrees of freedom (those supported by at least one cut cell). The immersed Newmark IMEX approach preserves the high-order convergence rates and the geometric flexibility of the finite cell method while retaining the efficiency of the nodal lumping scheme for uncut cells without compromising the critical time step size. We analyze a simple system of spring-coupled masses to highlight some of the essential characteristics of Newmark IMEX time integration. We then solve the scalar wave equation with immersed boundaries on two- and three-dimensional examples with significant geometric complexity to show that our approach is more efficient than state-of-the-art time integration schemes when comparing accuracy and runtime. While we focus on the finite and spectral cell methods, we expect other immersed methods to benefit equally from Newmark IMEX time integration. [ABSTRACT FROM AUTHOR]

In the present work, a complete numerical scheme to perform adaptive refinement and coarsening in the context of isogeometric analysis applied to thermomechanics is introduced. In particular, truncated hierarchical B-splines (THB-splines) are considered as a basis for the analysis and suitably graded isogeometric meshes are constructed to guarantee admissible configurations at each refinement and coarsening iteration. The algorithms are developed and implemented in a full three-dimensional framework and applied to solve coupled thermoelastic problems. The proposed numerical framework is verified on two relevant problems with respect to overkill solutions, obtained either with a commercial finite element software or with uniform isogeometric meshes. Different refinement and coarsening strategies are considered and compared. The obtained results demonstrate the ability of the THB-spline-based adaptive scheme to deliver robust discretizations guaranteeing a suitable trade-off between computational accuracy and number of degrees of freedom. [ABSTRACT FROM AUTHOR]

Clamping precision as a key factor of precision injection molding of high-quality plastic parts is restricted by low-precision clamping systems. Herein, a novel clamping method capable of sensing mold misalignment and self-adjusting mold position and attitude through floating structures is proposed to eliminate the restriction of clamping system, thereby achieving high clamping precision. The innovative clamping method possesses prestress steel wire-winding frames and rubber capsules filled with hydraulic oil, which ensures the floating structures work. Meanwhile, the hydraulic oil provides isostatic pressure to clamp the mold. The working space of the floating structures and the loading of the prestress steel wire-winding frames have been modeled to confirm their feasibility in the self-adaptive clamping method. Based on the modeling activities, a prototype injection molding machine was developed to evaluate the clamping precision. The experimental results indicate that the parallelism between the mold plates is 0.031 mm, far superior to that in China Machinery Industry Standards, and the uneven clamping force rate on mold cavity surface is 1.3 %. Moreover, the clamping force repeatability is only 0.14 %, superior to toggle and two-platen clamping systems. This method offers a new chance for the development of precision injection molding. • A novel clamping method capable of sensing mold misalignment and self-adjusting mold position and attitude. • The clamping method utilizes capsule with hydraulic oil to provide isostatic pressure and ensure floating structures work. • The prestress steel wire-winding frames in the clamping system cannot restrict degree of freedom of floating structures. • The developed clamping system is verified that the clamping precision is superior to traditional clamping systems. [ABSTRACT FROM AUTHOR]

This work proposes a hybrid modeling framework based on recurrent neural networks (RNNs) and the finite element (FE) method to approximate model discrepancies in time-dependent, multi-fidelity problems, and use the trained hybrid models to perform bias correction of the low-fidelity models. The hybrid model uses FE basis functions as a spatial basis and RNNs for the approximation of the time dependencies of the FE basis' degrees of freedom. The training data sets consist of sparse, non-uniformly sampled snapshots of the discrepancy function, pre-computed from trajectory data of low- and high-fidelity dynamic FE models. To account for data sparsity and prevent overfitting, data upsampling and local weighting factors are employed, to instigate a trade-off between physically conforming model behavior and neural network regression. The proposed hybrid modeling methodology is showcased in three highly non-trivial engineering test-cases, all featuring transient FE models, namely, heat diffusion out of a heat sink, eddy-currents in a quadrupole magnet, and sound wave propagation in a cavity. The results show that the proposed hybrid model is capable of approximating model discrepancies to a high degree of accuracy and accordingly correct low-fidelity models. • A RNN/FE hybrid model is developed to learn model discrepancies of multi-fidelity FE simulations based on trajectory data. • The RNN captures the dynamics of the discrepancy function while spatial discrepancies are resolved by a FE basis. • Upsampling and Gaussian priors are employed to account for sparsity in the discrepancy data and prevent overfitting. • The model is employed as a correction operator for low-fidelity models in three non-trivial test cases. • The bias corrected models are significantly more accurate compared to the original low-fidelity models. [ABSTRACT FROM AUTHOR]

A facile one-step non-contact process was developed for preparing the substrates for Fabry-Perot-based side-polished optical fiber sensors. A carbon dioxide (CO 2) laser cladding removal technique was used to control the profile of the polished fiber surface and to introduce two reflective cavities. The substrates were characterized for a range of cavity lengths and their thermal response was studied. This device added a degree of freedom to the design of optical fiber based Fabry-Perot sensors and its potential was demonstrated by coating the substrate with polydimethylsiloxane (PDMS). The resulting sensors had a three-order of magnitude increase in sensitivity when compared to the substrate. The polished flat surface provided a route for the integration of novel materials for sensing applications, particularly those where polarization control was vital for light-matter interaction, for example, low dimensional materials such as graphene or MXene. The inherent simplicity, mechanical stability, and scalability of this approach are important steps for the realization of practical devices of this type. [Display omitted] • The in-fiber resonator and side-polished fiber were fabricated with a CO 2 laser in one single step. • The large evanescent field of the side-polished fiber treated with 2D PDMS induced a change in the effective refractive index. • The FPIR-PDMS demonstrated excellent sensitivity, with the dip wavelength shifting by 1.27 nm/℃. [ABSTRACT FROM AUTHOR]

We present a novel semi-implicit hybrid finite volume/finite element (FV/FE) method for the equations of viscous and resistive incompressible magnetohydrodynamics (MHD). The scheme preserves the divergence-free property of the magnetic field exactly on the discrete level, is second order accurate in space, and is stable in the limit of vanishing viscosity and resistivity. In particular, the MHD system is first split into a fluid and a magnetic subsystem. The former is then addressed via a semi-implicit hybrid FV/FE method. The latter belongs to a class of generalized advection-diffusion problems, for which we propose a novel semi-implicit scheme based on compatible finite element spaces and interpolation-contraction operators. In the case of vanishing resistivity, the new algorithm avoids the solution of a linear system at each time step, thanks to the framework of physical degrees of freedom, which allow to express the exterior derivative as the incidence matrix of an appropriate refinement of the original mesh. Regarding the timestepping, a local fully-discrete Lax-Wendroff-type evolution is proposed as an alternative to the classical semi-discrete method of lines. In order to suppress spurious oscillations in the presence of discontinuities or steep gradients in the magnetic field, a new simple but efficient a posteriori limiting procedure based on a nonlinear artificial resistivity is introduced. The novel methodology is validated with several test cases in two and three space dimensions using unstructured simplex meshes. [ABSTRACT FROM AUTHOR]

We consider two-scale stress mixed finite element elasticity models using H(div)-conforming tensor approximations for the stress variable, whilst displacement and rotation fields are introduced to impose divergence and symmetry constraints. The variables are searched in composite FE spaces based on polyhedral subdomains, formed by the conglomeration of local shape-regular micro partitions. The two-scale characteristic is expressed in terms of refined discretizations inside the subdomains versus coarser normal components of tensors over their boundaries (traction), with respect to mesh size, polynomial degree, or both. General error estimates are derived and stability is proved for five particular cases, associated with stable single-scale local tetrahedral space settings. Enhanced accuracy rates for displacement and super-convergent divergence of the stress can be obtained. Stress, rotation, and stress symmetry errors keep the same accuracy order determined by the traction discretization. A static condensation procedure is designed for computational implementation. There is a global problem for primary variables at the coarser level, with a drastic reduction in the number of degrees of freedom, solving the traction variable and piecewise polyhedral rigid body motion components of the displacement. The fine details of the solution (secondary variables) are recovered by local Neumann problems in each polyhedron, the traction variable playing the role of boundary data. In this sense, the proposed formulation can be interpreted as an equivalent Multiscale Hybrid Mixed method, derived from a global-local characterization of the exact solution. A numerical example with known smooth solution is simulated to attest convergence properties of the method based on local B D F M divergence-compatible finite element pairs. Application to a problem with highly heterogeneous material is analyzed for robustness verification. • Multiscale method for 3D mixed weak symmetry elasticity approximations. • Theoretical analysis for the convergence of the stress and displacement. • Numerical results confirm theoretical convergence rates. • Method applied to highly heterogeneous 3D model. • Method results in elementwise equilibrated stress field. [ABSTRACT FROM AUTHOR]

Luneburg lenses prepared by alumina stereolithography, have the advantages of low dielectric loss, corrosion resistance, and flexible structure. However, the supporting structure limits the degree of geometric design freedom. This paper analyzes the effects of modifiers and dispersants on paste properties from the molecular structure, which is different from the traditional process that doesn't analyze the influence of similar mechanisms and binding site competition while ignoring the correlation. Based on the dispersant's better flexibility bringing more obvious change in viscosity, we first determine the amount of dispersant and then adapt the amount of modifier to obtain self-supporting pastes of 82 wt % and 24.9 Pa.swithout gradation. The gain and beam deflection angle of Luneburg lenses with high geometric complexity and working bandwidth of 38° formed by stereolithography self-supporting process is matched to the simulation results without manufacturing defects, which provides a theoretical basis for more flexible design and manufacture of Luneburg lenses. [ABSTRACT FROM AUTHOR]

SiC components were joined under vacuum at 1100 °C for 10 min via Si–Mg composite fillers with added Al (X Al) ranging over 0–10 at.%. The joining mechanism involves Mg addition to Si, which lowers the melting point of Si. The transformation of the molten liquid phase into a solid Si layer is induced by Mg evaporation. In SiC/SiC joining, however, Mg evaporation was significantly suppressed when X Al = 0 at.%, with a large amount of Mg remaining in the joint, forming a brittle bonding layer of Si, Mg 2 Si, and MgO. Notably, Mg evaporation was enhanced by the addition of Al to the filler, resulting in the formation of a dense Si layer. The joint tensile strength increased with increasing X Al in the range of 0–6 at.% and then decreased with further increases in X Al. The changes in strength were correlated with microstructural changes in the bonding layer. From the microstructure and the phase diagrams, it was concluded that the added Al increased the thermodynamic degrees of freedom, which hindered the rate of Mg-evaporation-induced Si solidification from the liquid during joining. Because the amount of liquid surrounded and trapped by the solid Si decreased, more Mg in the liquid could diffuse to the surface. [ABSTRACT FROM AUTHOR]

This paper examined uplink and downlink di-state (primary and secondary) situations to build the theoretical and practical realization of a bidirectional cooperative wireless cellular network. In the primary scenario, full-duplex (FD) base stations support two sets of half-duplex (HD) users, where the transmitter (uplink) and receiver (downlink) respectively. Each uplink transmitted signal is rotated in a variant phase through a set of scalars known to the base stations before transmission. The signal from the transmitter ensures the reconfigurable receiver antennas at the base stations can configure the received signal as decoded signals. The proposed work exposed strong self and inter-user interference from the transmitter during demonstrating FD wireless communication mode that destroyed network functionality at the base stations. The occurred self-interference signals from the transmitter are neutralized using precoding and beam-forming technique. During the secondary scenario, decoded base station signals are independently encoded and transmitted to the downlink users. Base stations aid the inter-user interference management by precoding the uplink transmission data and forwarding it to the downlink users. Consequently, the inter-user interference signals are aligned using the span interference alignment technique. A proposed cooperative additional receiver (listener U1) can decode the desired signals and helps in recovering and reconstructing the interference signals. This proposed work completely characterized and evaluated the degree of freedom (DoF) for unknown channel state information at the transmitter (CSIT); whereas achievable lower and upper bound DoF are demonstrated for the partial CSIT. At last, the analytical and simulation results reveal the sum of DoF improvement for unknown and partial CSIT. [ABSTRACT FROM AUTHOR]

An optimization procedure is presented for prescribing the empirical coupling parameters of a modified coupled van der Pol (VDP) wake oscillator and mass–spring–damper system for a one degree of freedom (1DOF) circular cylinder system undergoing vortex induced vibrations (VIV). This approach allows for the generalization of the traditional VDP model to cover a large VIV parameter range. The procedure is developed using experimental data covering the parameter space: 3 < U ∗ < 11 , 8 < m ∗ < 20 , 0. 003 < ζ < 0. 063 , R e D = 4000. The VDP model contains empirical coupling coefficients that describe the regime specific dynamic damping, ϵ , and wake coupling, β. Two calibration procedures are considered and the improvements over the traditional VDP model in predicting the VIV response are discussed. Subsequently, a regression fit is used to prescribe the two empirical coupling coefficients as functions of m ∗ , ζ and U ∗. The generalized model results in a better prediction of the VIV response in terms of identification of lock-in regimes, lock-in frequency and amplitude response over several regimes when compared to the classical models. The use of a functional representation replaces the need for using tables and reduces user input for determining regime-specific coupling coefficients. • Two wake oscillator models were developed using a large VIV experimental data set. • The tuned models predict the different lock-in regimes shown in experiments. • The models' empirical coefficients are strongly correlated to the m* , ζ and U*. • The models are ideal for situations where response regimes are not known a priori. [ABSTRACT FROM AUTHOR]

Semiconductor photolithography equipment requires an actuation system that can satisfy high acceleration and precision demands on the nanoscale in order to operate with high throughput and efficiency. Reluctance actuators, which offer greater acceleration and force output than conventional Lorentz actuators, are one option. The photolithography technique uses a floating stage with air bearings to reduce friction; nonetheless, vibration transfer is not completely prevented, potentially causing misalignment and asymmetries between the actuator components. The output force can be significantly impacted by unequal offsets between the mover and stator. In the paper that follows, a technique for calculating the force of various asymmetrical instances for the C-core reluctance actuator is demonstrated. This paper looks into the effect of rotational offsets in all rotational degrees of freedom occurring simultaneously. Previously, only each degree of freedom was analyzed. Analytical models are developed and compared to Comsol Multiphysics (COMSOL) simulations, and experimental findings show accuracy to be within almost 10% for the ranges examined. The findings presented can allow for future control systems to be designed to counteract multi-axial asymmetric issues. • Derived an analytical equation of the output force under multi-axial angular offsets. • Implemented a FEM setup to further tune the analytical output force equation. • Tested experimentally on multi-axial offset cases to verify the analytical model. [ABSTRACT FROM AUTHOR]

Recently, industrial robots have been widely used in manufacturing due to their various advantages when compared with other equipment, such as maneuverability in a wide range of workspaces, high degrees of freedom, and flexibility. However, due to the low stiffness, they are difficult to be used for precision metal cutting process those require high position control performance under cutting force. This paper proposes a compensation method that estimates the position error induced by the cutting force and compensates the error by controlling the workpiece position by using additional two-axis servo system. The cutting force model was constructed to estimate the cutting force generated during milling without sensors. The kinematic and stiffness models of the industrial robot were developed to calculate the angular error of each joint and position error of the tool center position caused by cutting force. To verify the performance of the proposed compensation method, series of experiments were conducted under various cutting conditions and compared with traditional on-line compensation method. The position accuracy was increased by 63.68 % after the application of the proposed compensation method. • Position error of the end effector caused by the cutting force is estimated. • A cutting force model is designed to predict the force acting on the tool. • Kinematics and stiffness models are constructed to estimate the position error. • Two-axis servo system controls the workpiece position for compensation. • Performance of proposed method is verified by comparing with traditional method. [ABSTRACT FROM AUTHOR]

This paper introduces a novel approach for regulating the pose of a free-flying dual-arm anthropomorphic space manipulator system (SMS) using a finite-time state-dependent Riccati equation (SDRE) controller. The proposed system finds applications in on-orbit satellite inspection, servicing, space structure assembly, and debris manipulation. The dual-arm SMS presented in this work consists of two 7 degrees of freedom (DoF) robotic arms mounted on a free-flying spacecraft, resulting in a complex 20-DoF system. Due to the high number of DoFs, advanced controller design and efficient computations are necessary. The finite-time SDRE controller relies on the state-dependent coefficient (SDC) parameterization matrices, which are nonlinear apparent linearizations of the dynamics. Conventionally, the computation of SDC matrices is offline and relies on the a priori derivation of the analytical equations governing the dynamics of the system. However, this strategy becomes computationally impractical for high DoF plants. To overcome this issue and deliver a more viable solution, a numerical method to construct and update the SDC matrices at each time step is presented. This approach relies on a screw-theory-based recursive Newton–Euler algorithm designed to reconstruct the manipulator inertia and Coriolis matrices. These quantities are the building blocks of the SDC parameters used in the synthesis of the SDRE controller. Simulation results demonstrate the performances of the finite-time SDRE controller augmented with the online update of the state-dependent coefficients. • Automatic derivation of the dynamics of free-flying robot with multiple open chains. • Implementation of a Newton-Euler approach for updating state-dependent coefficients. • Finite-time SDRE to control a 20 DoFs, anthropomorphic dual-arm space manipulator. [ABSTRACT FROM AUTHOR]

In this paper, we propose the application of an enriched Galerkin (EG) method to solve the elastic wave equation in the "displacement pseudo-pressure" mixed form, which is known for being locking-free. Unlike the continuous Galerkin (CG) method and the discontinuous Galerkin (DG) method, the EG method is based on the weak form of the DG method, and the enriched space combines a continuous piecewise linear vector-valued function space with some discontinuous piecewise linear functions. Specifically, we employ the enriched space to discretize the displacement, while the pseudo-pressure is discretized using the P 0 element space. As a result, compared to the DG method, the EG method significantly reduces the number of degrees of freedom. Furthermore, we adopt a more general θ -scheme for time discretization, which behaves as an implicit scheme for 1 4 ≤ θ ≤ 1 and as an explicit scheme for 0 ≤ θ < 1 4. We establish error estimates for both the semi-discrete and fully-discrete schemes. The accuracy of the proposed method is validated through numerical examples, which not only confirm the theoretical analysis but also provide simulations of elastic wave propagation. • Displacement pseudo-pressure mixed form of elastic wave equation. • Locking-free. • Enriched Galerkin mixed method. • Stokes projection technique. • Fully-discrete scheme based on 0 method. [ABSTRACT FROM AUTHOR]

In the quest of new absorbent for hydrogen storage, we investigate the capacities of slit pores formed by two BC 3 sheets decorated with Li atoms. Their hydrogen storage capacities are determined using density-functional theory in conjunction with a quantum-thermodynamic model that allows to simulate real operating conditions, i.e., finite temperatures and different loading and depletion pressures applied to the adsorbent in the charge-delivery cycles. We show that the capacities of the adsorbed hydrogen phase of Li-decorated BC 3 slit pores are larger than those reported recently for graphene and Li-decorated borophene slit pores. On the other hand, the usable volumetric and gravimetric capacities of Li-decorated BC 3 slit pores can meet the targets stipulated by the U.S. Department of Energy (DOE) for onboard hydrogen storage at moderate temperatures and loading pressures well below those used in the tanks employed in current technology. In particular, the usable volumetric capacity for pore widths of about 10 Å meets the DOE target at a loading pressure of 6.6 MPa when depleting at ambient pressure. Our results highlight the important role played by the rotational degree of freedom of the H 2 molecule in determining the confining potential within the slip pores and their hydrogen storage capacities. [Display omitted] • Li-decorated BC3 slit pores are promising materials for hydrogen storage. • Realistic predictions by combining DFT and a quantum-thermodynamic model. • The usable hydrogen storage capacities can reach the DOE targets. • The rotational degree of freedom of the H2 molecule plays an important role. [ABSTRACT FROM AUTHOR]

The κ -curve is commonly applied as a curvature pen tool in Adobe Illustrator® and Photoshop®. The κ -curve has an excellent property where the local maxima curvature occurred at the control points. Having the local maxima curvature at the control points gives salient features to the curve and keeps away the unintended creation of cusps and loops. However, the existing κ -curve has low degree of freedom since it was constructed from the classical quadratic Bézier curve with lack of local control shape, which will limit the flexibility and adjustability of curve modelling. Furthermore, the existing κ -curve needs to be optimized globally, where additional computational time is required when modifying control points. The κ -curve also only exhibits G 1 continuity at the inflection point. Hence, in this work, a new method is proposed to rectify the lower degree of freedom and to improve the flexibility and adjustability of the κ -curve. This study will also resolve the necessity of global optimization and adjust the smoothness of G 1 continuity at inflection point in the current κ -curve. The improved κ -curve can be constructed using the fractional Bézier curve with the help of fractional continuity. The fractional Bézier curve is equipped with shape and fractional parameters that will enhance the flexibility and adjustability of the curves while still maintaining the local maxima curvature at the control points. The algorithms for the construction of the modified κ -curve will be shown by using the fractional Bézier curve and fractional continuity. The nature of fractional continuity in the proposed algorithms will prevent the global optimization and guaranteed the G 2 / F 2 continuity everywhere. Therefore, the modified κ -curve is expected to rectify the aforementioned issues. [ABSTRACT FROM AUTHOR]

The migration and wake structure of a single bubble in a viscous medium near a vertical wall have been experimentally investigated using a two-camera orthogonal shadowing method combined with a particle image velocimetry system. The effects of bubble size, liquid properties, and migration modes on the motion of a near-wall bubble and its wake structure are discussed. It is shown that, unlike migration in pure water, collisions between bubbles and walls are rare in viscous liquids. As viscosity increases, the mobility of the bubble near the wall changes from 3D to 2D and finally exhibits 1D motion with only one degree of freedom. While 1D motion is dominated by viscous forces, 2D migration is influenced by both wall effects and viscous forces, while 3D migration is primarily affected by bubble size. After analyzing the wakes produced by different factors, it was found that the wakes generated by mobile bubbles in three dimensions exhibit similar shedding patterns to Karman vortex streets, while two-dimensional wakes show stronger continuity. The average topological flow field structure of the bubble wake is obtained through periodic phase averaging, and the effect of different factors on the evolution of near-wall bubble wakes is analyzed. • Phase-averaged analysis of the wake behind a near-wall bubble. • The impact of size and viscosity on the migration of a near-wall bubbles. • Shedding of near-wall bubble wakes. [ABSTRACT FROM AUTHOR]

This work introduces a solid-shell element with eight nodes for the bending behavior of structures embedded with piezoelectric layers using the FSDT theory. The mechanical degrees of freedom are coupled, through the constitutive equations, with the piezoelectric one considering the linear distribution of the electric potential along the piezoelectric face's thickness. In order to subdue shear and thickness locking, the Assumed Natural Strain (ANS) method as well as the Enhanced Assumed Strain (EAS) method are adopted. Bonding the external faces of shell structures with piezofaces accentuates the smart aspect of solid shells. The middle part of the structure is made of a Functionally Graded Material (FGM) with distributed pores along the thickness. The formulated finite element model is implemented to investigate the effects of some parameters on the bending response of solid shells such as the impact of various configurations of porous FGM, the power law index of FGM and some geometrical parameters of solid shell structures. [ABSTRACT FROM AUTHOR]

• Extension of the s-version FE method to non-linear material problems was proposed. • A strategy to improve efficiency of constructing stiffness matrices was introduced. • Accuracy and efficiency were validated with a 3D stress concentration problem. • This study simplifies modelling structures with defects and material nonlinearity. This study intended to extend the s-version of the finite element method (s-version FEM) to cope with elastic–plastic problems. Compared with the conventional FEM, the s-version FEM, which overlays a set of local mesh with fine element size representing irregular features over the conventional FE mesh with coarse element size, can considerably simplify issues in domain discretisation with fewer degrees of freedom and provide accurate numerical predictions. However, most applications of the s-version FEM were limited to elastic problems only, leaving its applications to elastic–plastic problems almost blank owing to insufficient instructions on stress update when plasticity sets in. To address these issues, detailed instructions and formulations to cope with plasticity problems with the s-version FEM were presented for its first time. The recursive element subdivision technique was implemented to generalise its application where local elements intersect with global element edges. A 3D stress concentration problem with linear/non-linear material properties was analysed; their numerical results were compared with the exact solutions and those obtained from the conventional FEM with very fine elements. The comparison highlights the flexibility of the s-version FEM in domain discretisation and its superior accuracy in numerical calculations, thereby exhibiting high potential applications in structural integrity assessment with complex structures, geometric defects, and material non-linearity. [ABSTRACT FROM AUTHOR]

• A high-efficient model for vehicle-track-soil dynamic interaction based on hybrid solution method. • Cyclic calculation boundary and multi-time-step strategies are integrated into the hybrid model. • The proposed hybrid model can evaluate the vehicle-track-soil performance efficiently without losing accuracy. To meet the demand for dynamic analysis of railway engineering structures accurately, the numerical model considering the coupled vibrations of the vehicle, track and substructure becomes a research tendency. However, it generates low-efficiency risk due to high degrees of freedom of the model. In this paper, a hybrid integration method based on the implicit scheme and Green's function is introduced and combined with the cyclic calculation method and the multi-time-step solution method to optimize the dynamic procedure for high-efficient solution of vehicle-track-soil (VTS) dynamic interaction. The VTS system is divided into two sub-models: vehicle-rail sub-model and the track slab-soil sub-model. The compatibility between two sub-models is maintained by the equilibrium mechanism of the fasteners' interaction forces. Through detailed validation, discussion and numerical studies, the feasibility and efficiency of the proposed model combing the hybrid integration method and two optimized dynamic solution strategies are fully demonstrated in the dynamic assessment of VTS dynamic interaction. [ABSTRACT FROM AUTHOR]

In correlated oxides, collaborative manipulation on light intensity, wavelength, pulse duration and polarization has yielded many exotic discoveries, such as phase transitions and novel quantum states. In view of potential optoelectronic applications, tailoring long-lived static properties by light-induced effects is highly desirable. So far, the polarization state of light has rarely been reported as a control parameter for this purpose. Here, we report polarization-dependent metal-to-insulator transition (MIT) in phase-separated manganite thin films, introducing a new degree of freedom to control static MIT. Specifically, we observed giant photoinduced resistance jumps with striking features: (1) a single resistance jump occurs upon a linearly polarized light incident with a chosen polarization angle, and a second resistance jump occurs when the polarization angle changes; (2) the amplitude of the second resistance jump depends sensitively on the actual change of the polarization angles. Linear transmittance measurements reveal that the origin of the above phenomena is closely related to the coexistence of anisotropic micro-domains. Our results represent a first step to utilize light polarization as an active knob to manipulate static phase transitions, pointing towards new pathways for nonvolatile optoelectronic devices and sensors. [ABSTRACT FROM AUTHOR]

Matrix production systems are modular, cycle time-independent, and flow-oriented production systems. They combine flexibility plus productivity and consist of flexibly linked and freely accessible process modules. The derivation and design of these process modules in flexible structures is still very time-consuming due to many degrees of freedom and limiting constraints. This paper presents a method for deriving flexible process modules, taking into account the creation of increased automation potentials, flexible order flows, and specialization in processes. The method consists of seven steps to derive harmonized process modules for multiple products. It is suitable for all manufacturing industries to reduce the planning effort. The defined process modules can be further used for layout planning. [ABSTRACT FROM AUTHOR]

This paper reports the development and displacement self-sensing of a new four degrees-of-freedom (DOF) piezoelectric micromanipulator. In particular, each micromanipulator arm can move along the clamping and vertical directions, constructing with two degrees of freedom, and two micromanipulator arms exhibit four degrees of freedom. Thus, it improves operational flexibility. Meanwhile, the self-sensing method avoids additional external sensors when detecting output displacements. The piezoelectric micromanipulator is devised based on the transverse inverse piezoelectric effect of two sets of vertical spatial crossings. Static and dynamic characteristics are analyzed via finite element optimization of geometric parameters. Then, a displacement self-sensing method based on charge integration is proposed. This method measures the generated charge on the clamping arm surface from the piezoelectric wafer deformation under the driving voltage. A self-sensing circuit is designed to obtain the surface charge of the clamping arm. Then, several experiments are conducted to test the micromanipulator. The maximum displacements of the designed micromanipulator are about 66.29 μm and 63.09 μm along clamping and vertical directions. Moreover, output displacements, response time, and inherent frequencies obtained based on the self-sensing method agree well with those with laser sensors. In addition, an operation application for micro-shaft assembly is presented, demonstrating the grasping and docking operations of the micro-shaft in the clamping and vertical directions. • A new four-degree-of-freedom piezoelectric micromanipulator. • Self-sensing method for output displacement based on integral charge. • Various experiments and verifications. [ABSTRACT FROM AUTHOR]

Robotic thoracic surgery is a minimally invasive technique that allows the surgeon to perform delicate, accurate surgical manoeuvres within the chest cavity without rib spreading. Previous studies have suggested potential benefits of the robotic platform in nodal upstaging due to its versatility, seven degrees of freedom of movement, and superior vision. However, there is currently a paucity of robust clinical data from Australia. This study aimed to assess the perioperative safety and oncological efficacy of anatomical pulmonary resections performed using the robotic platform. Endpoints included mortality and major morbidity outcomes according to Clavien–Dindo classification and rate of pathological nodal upstaging compared with preoperative imaging using positron emission tomography. A single-surgeon retrospective analysis was performed using data collected from two institutions from July 2021 to May 2022, after ethics committee approval. Consecutive patients who underwent anatomical robotic resections were included in the study, with subsequent analysis of patients who had confirmed primary lung cancer. A total of 52 patients underwent robotic anatomical pulmonary resection during the study period. Safety was demonstrated by 0% mortality and a 9.6% major complication rate, which was related to chest tube insertion for prolonged air leak or intensive care unit monitoring during treatment of atrial arrhythmia. After excluding patients who did not have primary lung cancer, 48 patients remained for further analysis; pathological nodal upstaging was observed in nine (18.8%) of these patients. On multivariate analysis, the total number of lymph nodes harvested was found to be a statistically significant predictor of nodal upstaging. Complete microscopic resection (R0) was achieved in 100% of patients. This study represents the most extensive documentation of robotic thoracic procedures in Australia in the existing literature. It demonstrated a satisfactory safety profile with a relatively high rate of nodal upstaging, possibly reflecting the ability of the robotic instruments to perform comprehensive and complete nodal resection at the time of anatomical pulmonary resection. [ABSTRACT FROM AUTHOR]

We present a particular derivation of the face-centred finite volume (FCFV) method and study its performance in non-linear, coupled transport problems commonly encountered in geoscientific and geotechnical applications. The FCFV method is derived from the hybridisable discontinuous Galerkin formulation, using a constant degree of approximation for the discretization of the unknowns defined on the mesh faces (edges in two dimensions). The piecewise constant degrees of freedom are determined in a global problem over the mesh skeleton. Then, the solution and its gradient are recovered at the cells centroid in a set of element-by-element independent postprocesses, both exhibiting linear convergence. The formulation of the transient advection-diffusion-reaction equation is presented in detail and the numerical analysis under challenging advective/diffusive regimes is studied. Finally, we use several numerical examples to illustrate the advantages and limitations of the FCFV method to solve problems of geoscientific and geotechnical relevance governed by the non-linear coupling between advection-diffusion-reactive transport and Stokes flow. Our results show that the FCFV method is an attractive and highly competitive alternative to other commonly used methods. • FCFV approach for solving ADR problems coupled with Stokes flow. • Linear convergence of the primal variable's gradient without flux reconstruction. • Accurate in advection-dominated scenarios with both uniform and distorted meshes. • All unknowns defined on the same nodes, favourable for non-linear coupled problems. • Performance is validated with multiple challenging cases of geoscientific relevance. [ABSTRACT FROM AUTHOR]

• A ROM methodology is proposed to solve convective-dominant conjugate heat transfer flows. • Numerical validation of the methodology is done exhaustively with benchmark solutions. • A mesh-based hyper-ROM approach is used to assess fast numerical approximations. • The use of ROM in all the unknown fields or only in the velocity and pressure is compared. • Speed-up of three hundred times is obtained through the use of ROM methodologies. This article presents a full and reduced-order methodology based on the finite element method that allows the characterization of convective-dominant conjugate heat transfer flows. Reduced-order modeling (ROM) allows the description of several degrees of freedom problems, referred to as full-order modeling (FOM), through a reduced-order surrogate representation based on a Petrov-Galerkin projection onto a reduced subspace. The FOM and ROM problems are stabilized through the Variational Multi-Scale (VMS) method, which ensures stability in dominant convective problems and allows equal interpolation spaces for the pressure, velocity, and temperature. The proposed methodology is validated solving natural heat convection in a differentially heated square cavity, considering air as the working fluid and Rayleigh numbers in the interval 10 4 ≤ Ra ≤ 10 8. In this problem, the benefit of using a ROM approximation for the three unknown fields, i.e., velocity, pressure, and temperature, is compared against ROM approximation only in the velocity and pressure fields and a FOM type approximation for temperature. The benefit of using mesh-based hyperreduction and its computational performance and precision are also analyzed. Subsequently, the method simulates a conjugate heat transfer problem that includes natural heat convection, allowing the inclusion of different rheologies between the working fluids. The results verify the precision and speed up of the calculations by more than three hundred times with respect to the time necessary to solve a full-order formulation, emerging it as a great potential tool in the resolution of thermally coupled flows. [ABSTRACT FROM AUTHOR]

Modern medical implants are characterized by non-circular shapes, which is often challenging for economic production. Non-Circular-Rotary-Turning (NCRT) is a newly developed process for manufacturing non-circular cross-sections at high productivity and a high degree of geometric freedom. In this work, the basic process kinematics of NCRT are presented. A process design method is proposed and validated. The fundamental cutting conditions are examined using simulation and the cutting forces are studied experimentally. In an example of application, NCRT enables to reduce machining time by a factor of more than ten compared to a conventional process chain, resulting even in better surface quality. [ABSTRACT FROM AUTHOR]

In this paper, a nonlinear control strategy is proposed for a pneumatic manipulator based on an adaptive extended state observer and a backstepping integral sliding mode controller. A single degree of freedom dynamic model is established for the pneumatic manipulator using an Euler–Lagrange dynamic equation. The adaptive extended state observer is designed by an adaptive law to estimate uncertainties and disturbances. The backstepping integral sliding mode controller is proposed using an integral sliding mode surface based on backstepping technique. Comparative experiments verify effectiveness of the proposed nonlinear control strategy for the pneumatic manipulator. • Combining a PAM model and an Euler Lagrange model, a practical dynamic model is proposed for a pneumatic manipulator. • An adaptive law is designed for the adaptive parameter in both an AESO and a backstepping sliding mode controller. • A backstepping sliding mode controller is designed with an adaptive parameter and an integral sliding mode function. [ABSTRACT FROM AUTHOR]