Resolver angle estimation using parameter and state estimation

In this paper, a new type of a resolver angle estimator that utilizes a combined parameter and state estimation scheme is proposed. A state-space model of a resolver is first developed with unknown parameters. Least square estimation is employed to obtain some unknown model parameters by using the measurements up to the current time. Based on the state-space model with estimated parameters, a constrained state estimator with finite memory is constructed to estimate the resolver angle. It is shown through simulation that the proposed scheme is very effective in suppressing noise and overcoming amplitude and phase imbalances compared with common angle tracking observers.     

Expansion of pipe blanks

The development of new shaping technologies for pipe blanks requires simulation of the stress and strain fields, which permits assessment of the limiting stress and strain values. The stress–strain state of a pipe blank in expansion (including nonuniform expansion) is analyzed in the present work. Joint solution of the equilibrium equations and plasticity condition is employed here; that is the traditional approach. Analytical dependences of the stress in the wall of the pipe blank on the technological parameters are obtained; the basic formulas for estimating the strain are also presented. Experiments confirm the results.     

Damage state assessment method for remanufacturing blanks based on magnetic and surface texture feature fusion

In order to improve the accuracy and efficiency of damage assessment, a novel method to evaluate the damage state for remanufacturing blanks based on the magnetic and surface texture feature fusion was developed. Through modeling of the magnetic and surface texture features, sample entropy parameters from the magnetic intensity and its gradients were extracted, and energy, entropy, contrast, and correlation parameters from surface texture were obtained. The two-layered feature fusion model comprised of the data layer and the index layer was established. In the data layer, parameters of the magnetic and surface texture features and their nonlinear mapping relationships with damage were obtained. In the index layer, the information fusion between the magnetic and surface texture features was carried out by Dempster-Shafer (D-S) evidence theory. Finally, fatigue test samples were selected to verify the feasibility of the proposed method. Results show that the method can be used to determine the damage states of the remanufacturing blanks, which provides theoretical and technical decision support for remanufacturability of the components.     

Feasibility studies on manufacturing tailored blanks by rolling partially stacked blanks

Tailored blanks with different blank thicknesses are semi-finished parts that can be used to produce lightweight vehicle parts. This study investigates a manufacturing process that can produce tailored blanks by rolling partially stacked blanks. The process was experimentally and numerically investigated using various processing conditions. To characterize the process, the deformation behaviors of upper and lower blanks were analyzed and quantified. The dimensional variations at the top end and the transition zones were analyzed based on the cross-sectional thickness profiles of formed blanks. The results show that the proposed process is feasible for the production of tailored rolled blanks that have both straight edges with a concave transition zone and convex edges with a straight transition zone.     

冲压件的智能排样

本文提出针对冲压件的一种基于知识的智能优化排样技术。把数学方法、子目标法、启发式搜索法及符号推理方法有机集成，协同求解。首次将制件下料技术的作业性作为排样的一种约束条件，探讨了智能优化排样的一些关键技术方法。     

Hybrid technologies in the production of manufacturing blanks

Economical short-run production technologies for manufacturing blanks are proposed.     

Vibroacoustic: The challenges of a mission impossible?

Why it is difficult to solve a vibroacoustic problem; what are the hidden pitfalls that one is called to overcome; are there methods or techniques suggested in other fields of physics that can help to formulate an efficient vibroacoustic prediction model? The authors provide personal answers to these questions and suggest also a classification of the numerous prediction methods proposed in the literature.     

Basing of cylindrical blanks on prisms

The basing of cylindrical blanks on prisms is analyzed. A new approach to selecting bases and basing configurations is proposed.     

Clock state estimation with the Kalman-like UFIR algorithm via TIE measurement

We show that recently designed the p-shift unbiased finite impulse response (UFIR) iterative algorithm is highly efficient in applications to clock state estimation via measurement of the time interval error (TIE). The algorithm is Kalman-like, but does not involve noise statistics and initial errors. Its crucial property is that the estimate becomes optimal in the minimum mean square error sense when the estimator memory is large that is typical for clocks. Examples are given for state estimation in an ovenized crystal clock and error prediction in a master clock. Based upon the experimental studies, we show that this algorithm outperforms the Kalman filter requiring the clock noise covariance matrix that is hard to specify correctly even in white Gaussian approximation.     

Cooling of superhard tools in the finishing of grinding-wheel blanks

Attention focuses on the cooling of tools by liquid jets and the use of composite wheels with aerodynamic cooling.     

Cutting complex blanks from anisotropic materials

A die for cutting out complex shell profiles is proposed. The number and directions of the scallops are determined. The efficiency in utilizing the material is estimated.     

Acoustic-emission quality control of plastically deformed blanks

The questions of modeling the process of failure under plastic restructuring of a material, the transformation of the strength state of the material of plastically deformed blanks into the state of the article material, the acoustic-emission assessment of the faultiness of the end item, and the liability of the flaws in a blank to development under rolling are considered.     

Primary and secondary factors affecting the basing precision of blanks

A method is proposed for determining the reference bases and their normalized sections for dimensions specified on the drawings. As an example, the bases are analyzed for a drawing of a prismatic part. The primary and secondary factors that affect the basing error are outlined. The influence of these factors on the basing precision is outlined, for a prismatic blank.     

Bulge forming of vessels from flat blanks

A forming process is suggested for producing vessels or containers of required shape from sheet metal by drawing, ironing and bulging under internal pressure and axial compressive force in one continuous operation. The process has been successively applied in the present series of tests for forming spherical and conical aluminium vessels.     

Decentralized state estimation for a large-scale spatially interconnected system

A decentralized state estimator is derived for the spatially interconnected systems composed of many subsystems with arbitrary connection relations. An optimization problem on the basis of linear matrix inequality (LMI) is constructed for the computations of improved subsystem parameter matrices. Several computationally effective approaches are derived which efficiently utilize the block-diagonal characteristic of system parameter matrices and the sparseness of subsystem connection matrix. Moreover, this decentralized state estimator is proved to converge to a stable system and obtain a bounded covariance matrix of estimation errors under certain conditions. Numerical simulations show that the obtained decentralized state estimator is attractive in the synthesis of a large-scale networked system.