Systematic Modeling Method Research Articles

Digital twin modeling method based on biomimicry for machining aerospace components

High-performance aerospace component manufacturing requires stringent in-process geometrical and performance-based quality control. Real-time observation, understanding and control of machining processes are integral to optimizing the machining strategies of aerospace component manufacturing. Digital Twin can be used to model, monitor and control the machining process by fusing multi-dimensional in-context machining process data, such as changes in geometry, material properties and machining parameters. However, there is a lack of systematic and efficient Digital Twin modeling method that can adaptively develop high-fidelity multi-scale and multi-dimensional Digital Twins of machining processes. Aiming at addressing this challenge, we proposed a Digital Twin modeling method based on biomimicry principles that can adaptively construct a multi-physics digital twin of the machining process. With this approach, we developed multiple Digital Twin sub-models, e.g., geometry model, behavior model and process model. These Digital Twin sub-models can interact with each other and compose an integrated true representation of the physical machining process. To demonstrate the effectiveness of the proposed biomimicry-based Digital Twin modeling method, we tested the method in monitoring and controlling the machining process of an air rudder.

A Systematic Method for Predictive In Silico Chemical Vapor Deposition

A comprehensive systematic method for chemical vapor deposition modeling consisting of seven well-defined steps is presented. The method is general in the sense that it is not adapted to a certain ...

Dependency and correlation analysis of specifications and parameters of products for supporting design decisions

Design changes often occur during product development processes and some design changes may require significant modifications of product specifications and design parameters, which may affect life cycle performances of the product. Due to complexities and possibly unknown relationships among specifications and parameters of products, the design change decisions must be carefully evaluated. This paper proposes a systematic method for modeling and analysis of dependencies and correlations among product specifications and critical design parameters for supporting design decisions. A case study illustrates the feasibility and effectiveness of the proposed approach.

Formalising the Hybrid ERTMS Level 3 specification in iUML-B and Event-B

We demonstrate refinement-based formal development of the hybrid, ‘fixed virtual block’ approach to train movement control for the emerging European Rail Traffic Management System (ERTMS) level 3. Our approach uses iUML-B diagrams as a front end to the Event-B modelling language. We use abstraction to verify the principle of movement authority before gradually developing the details of the Virtual Block Detector component in subsequent refinements, thus verifying that it preserves the safety properties. We animate the refined models to demonstrate their validity using the scenarios from the Hybrid ERTMS Level 3 (HLIII) specification. We reflect on our team-based approach to finding useful modelling abstractions and demonstrate a systematic modelling method based on the state and class diagrams of iUML-B. The component and control flow architectures of the application, its environment and interacting systems emerge through the layered refinement process. The runtime semantics of the specification’s state-machine behaviour are modelled in the final refinements. We discuss how the model could be used to generate an implementation using code generation tools and techniques.

Publisher’s Note: “A systematic error modeling and separation method for the special cylindrical profile measurement based on 2-dimension laser displacement sensor” [Rev. Sci. Instrum. 90, 105006 (2019)

Publisher’s Note: “A systematic error modeling and separation method for the special cylindrical profile measurement based on 2-dimension laser displacement sensor” [Rev. Sci. Instrum. 90, 105006 (2019)

A systematic error modeling and separation method for the special cylindrical profile measurement based on 2-dimension laser displacement sensor

The aim of this study is to improve aeroengine multistage rotor performance and to reduce the incidence of failures. Measuring the form error of seam allowance connecting cylindrical surface accurately is critical to achieve rotor optimal stack assembly stage-by-stage. In this paper, compared to the traditional cylindrical profile measurement model, a more comprehensive measurement model was built based on a 2-dimensional line laser sensor measurement technique, a model in which the component eccentricity error e, the sensor lateral offset error d, the sensor forward tilt error θx, the sensor lateral tilt error θy, and the rotary table tilt error γ were gradually modeled and separated. The particle swarm optimization algorithm was adopted to solve the model error parameters. The residual error simulation was performed to observe the effect of different levels of offset errors on the measurement results. The aeroengine rotor seam allowance surface measurement experiment was performed to verify the validity of the method model. We can conclude that the sensor lateral offset error d was 3.214 µm, sensor forward tilt error θx was 12.754″, sensor lateral tilt error θy was 10.365″, and rotary table tilt error γ was 2.146″. The cylindricity error value was 3.701 µm. Compared with the traditional cylindrical profile measurement method, the measurement accuracy of cylindricity error was improved by 1.768 µm. The proposed method can improve the measurement accuracy significantly of multistage rotors in the aeroengine measurement process; besides, it can also be extended to the measurement of other geometric form errors.

Process quality control of the manufacturing of Chinese Materia Medica by process analysis technology

Process quality control is essential for the manufacturing of Chinese Materia Medica. Non-destructive monitoring is still a challenge for the quality control of Chinese Materia Medica manufacturing. As the commonly used non-destructive process analysis technology, near infrared spectroscopy, near infrared chemical imaging, and laser-induced breakdown spectroscopy have been applied to the quality control of Chinese Materia Medica manufacturing. The characteristic near infrared bands of 29 natural chemical components have been assigned. Ten spectral pre-processing methods and five variable selection methods have been optimized, respectively. Given the interrelationship among modeling parameters, a system modeling concept was put forward to establish a global model. Accuracy Profile was further proposed as the validation method of models. In addition, the homogeneity of chlorpheniramine maleate tablets from six brands was successfully visualized by near infrared-chemical imaging. As and Hg variation in An-Gong-Niu-Huang Wan have been rapidly monitored by laser-induced breakdown spectroscopy. A systematic modeling method (model establishment, evaluation, and validation) and the non-destructive technology of homogeneity visualization and toxic element detection have been developed for quality control of Chinese Materia Medica manufacturing, which is shown in Figure 1 of the article. These achievements have greatly promoted the research and application of process analysis technology in Chinese Materia Medica manufacturing, laying a solid foundation for the development of intelligent Chinese pharmaceutical industry.

Modeling and Control of Heterogeneous Agricultural Field Robots Based on Ramadge–Wonham Theory

Cooperation among heterogeneous agricultural field robots in an agricultural environment guarantees the advantages of effectiveness and scalability. However, traditional control theories for coordination among multiple heterogeneous robots lack a systematic modeling method and a control strategy under unstructured and uncertain environments. To handle these limitations, a novel approach based on the Ramadge–Wonham theory and discrete event system is proposed in this letter. Specifications and a supervisory controller based on discrete event models were defined from an agricultural perspective considering cooperation among heterogeneous agricultural field robots. Discrete event systems were modeled through the automata theory and the behavior of heterogeneous field robots satisfied the designed specifications. The resulting supervisor ensures that the control objectives of formation control, obstacle avoidance, movements, and path following are satisfied. The approach and architecture proposed in this study were validated using a physics-based simulator and field experiments.

Closed-form dynamic modeling and performance analysis of an over-constrained 2PUR-PSR parallel manipulator with parasitic motions

This paper presents an systematic dynamic modeling and performance analysis method of an over-constrained 2PUR-PSR parallel manipulator with parasitic motions, where P, U, S, and R represent the prismatic joint, universal joint, spherical joint, and revolute joint, respectively. The process of the deduction of the over-constrained forces/moment is given. The Newton–Euler approach and natural orthogonal complement method are adopted to establish two types of dynamic models with and without constrained forces/moments with the consideration of the over-constrained forces/moments. The dynamic manipulability ellipsoid, which measures the uniformity of changing the position and orientation of the manipulator’s moving platform, is adopted to evaluate the dynamic performance of the parallel manipulator. To show the feasibility of the proposed method, numerical simulations are conducted to investigate the dynamic models and performance of the 2PUR-PSR manipulator. The actuation forces, constrained forces/moments, and the compatible deformation are calculated. Distribution of the DME index is also obtained. The proposed modeling approach provides a fundamental basis for the structural optimization and control scheme design of the over-constrained parallel manipulator.

Rapid Modeling and Parameter Estimation of Partial Differential Algebraic Equations by a Functional Spreadsheet Paradigm

We present a systematic spreadsheet method for modeling and optimizing general partial differential algebraic equations (PDAE). The method exploits a pure spreadsheet PDAE solver function design that encapsulates the Method of Lines and permits seamless integration with an Excel spreadsheet nonlinear programming solver. Two alternative least-square dynamical minimization schemes are devised and demonstrated on a complex parameterized PDAE system with discontinues properties and coupled time derivatives. Applying the method involves no more than defining a few formulas that closely parallel the original mathematical equations, without any programming skills. It offers a simpler alternative to more complex environments which require nontrivial programming skill and effort.

Modeling and dynamic analysis of accessory drive systems with integrated starter generator for micro-hybrid vehicles

Belt-driven integrated starter generator system is a hybrid transmission that resembles the conventional serpentine belt-driven system. The system contains an integrated starter generator that performs a “start-stop” function on the engine. A two-pulley tensioner mechanism is attached to the integrated starter generator to maintain belt tension. The objectives of this paper are to develop modeling and calculation methods for estimating the performances of the belt-driven integrated starter generator system and to investigate the influence of damping of the two-pulley tensioner on vibration and shock. A systematic modeling and analysis method is proposed. The modeling method for the two-pulley tensioner is distinguished from any existing studies, which are generic for modeling the tensioner in belt-driven integrated starter generator systems with different layouts. A typical belt-driven integrated starter generator system is presented and a model is established to predict the dynamic response of rotational vibrations of pulleys, tensioner motions, and tension fluctuations. A parametric analysis is conducted to evaluate the two-pulley tensioner parameters with respect to their impact on the performances of the belt-driven integrated starter generator system.

Identification of spin maneuver aerodynamic nonlinear model by applying ensemble empirical mode decomposition and extended multipoint modeling

Identification of the “aircraft aerodynamic model” in some unusual flight conditions such as spin maneuver provides critical information to the flight controller to retake the “dynamic stability” after it has been disturbed by the systematic, natural or environmental oscillations. Hence, a method for identifying the appropriate aerodynamic model in spin maneuvers is presented in this paper. We present an innovative systematic method for aerodynamic modeling of spin maneuvers, which combines the ensemble empirical mode decomposition technique and extended multipoint modeling approach, using flight data. In ensemble empirical mode decomposition, in addition to having all the empirical mode decomposition features, the original signal is collected with the white noise, and by using its statistical characteristics, the ensemble empirical mode decomposition solves the mode mixing problem. By applying the ensemble empirical mode decomposition to the flight parameter data, their intrinsic mode frequencies are extracted and are used as inputs to the extended multipoint modeling model. The extended multipoint modeling structure includes some parameters describing the distribution of aerodynamic forces and moments along each of the aircraft components. Moreover, this method allows coupling between the forces and moments. Unlike conventional methods, which consider the average forces obtained by plane surfaces relative to the center of mass, in the extended multipoint modeling technique, the force generated by each plane of the aircraft is allowed to appear independently in the motion equations. For identifying the aerodynamic model with extended multipoint modeling structure, the equation error method is used with a maximum likelihood optimizer inside. The obtained algorithm has been applied to two sets of spin maneuver flight data which were recorded in actual spin flight. The results demonstrate that the proposed method is able to reproduce the aerodynamic forces and moments for the second spin flight inputs with high accuracy by using a model which is derived from the first spin data identification.

A qualitative knowledge representation model and application for crisis events

Emergency management information system requires lots of qualitative knowledge of crisis events, such as empirical knowledge, common-sense knowledge, etc., but as to the complexity of the crisis events, existing studies about qualitative knowledge have not formed systematic modeling method, and the knowledge representation model established cannot get personalized extension or their extendibility is not very well. In addition, relationships between any two crisis events cannot be supported and connected by the qualitative knowledge. Therefore, based on the system engineering point of view, this paper abstracts the common elements, that is, the ontology model of the evolutionary process of the crisis events, and creates the corresponding meta-model. Based on the above two models, by using framework structure and production rules, a personalized and extensible general qualitative knowledge representation model for crisis events is constructed, and then, according to the causal relationships between crisis events, the crisis events chain model which can realize the evolutionary process automatically is also constructed. Finally, a well-designed prototype system shows the application of the proposed model.

Planar Multibranch Open-Loop Robotic Manipulators Subjected to Ground Collision

In this article, a recursive approach is used to dynamically model a tree-type robotic system with floating base. Two solution procedures are developed to obtain the time responses of the mentioned system. A set of highly nonlinear differential equations is employed to obtain the dynamic behavior of the system when it has no contact with the ground or any object in its environment (flying phase); and a set of algebraic equations is exploited when this tree-type robotic system collides with the ground (impact phase). The Gibbs–Appell (G–A) formulation in recursive form and the Newton’s impact law are applied to derive the governing equations of the aforementioned robotic system for the flying and impact phases, respectively. The main goal of this article is a systematic algorithm that is used to divide any tree-type robotic system into a specific number of open kinematic chains and derive the forward dynamic equations of each chain, including its inertia matrix and right-hand side vector. Then, the inertia matrices and the right-hand side vectors of all these chains are automatically integrated to construct the global inertia matrix and the global right-hand side vector of the whole system. In fact, this work is an extension of Shafei and Shafei (2016, “A Systematic Method for the Hybrid Dynamic Modeling of Open Kinematic Chains Confined in a Closed Environment,” Multibody Syst. Dyn., 38(1), pp. 21–42.), which was restricted to a single open kinematic chain. So, to show the effectiveness of the suggested algorithm in deriving the motion equations of multichain robotic systems, a ten-link tree-type robotic system with floating base is simulated.

Estimation and Compensation of the LuGre Friction Model in High-Speed Micro-Motion Control

Static friction compensation is usually required to reduce friction in precision motion control and manufacturing processes. Micro-motion control is a current trend for precision machining in the electronics industry. Dynamic friction plays an important role in systems using micro-scale motion at high-speed and high-frequency command. The Lund–Grenoble (LuGre) friction model is suitable for coping with the dynamic friction effect. However, the parameters of this model are difficult to accurately identify to ensure satisfactory control performance in miniature machining. This paper proposes an efficient and systematic three-step parameter estimation method for LuGre modeling. The friction compensation of the proposed approach was successfully demonstrated on a 400W AC servo motor. Furthermore, under a peck drilling command on DYNA 1007 CNC machine, the LuGre model also improved motion precision by 72.0% in the maximum peak error.

Parameter Extraction and Wideband Modeling of $\pm $ 1100 kV Converter Valve

As the key equipment of ultra-high-voltage direct-current (UHVDC) transmission systems, the converter valve would bear different forms of overvoltage. Consequently, a wideband model for the $\pm $ 1100 kV UHVDC converter valve is essential for the converter system to make overvoltage analysis, insulation design, and electromagnetic disturbance prediction. This paper proposed a wideband modeling method for the $\pm $ 1100 kV converter valve. First, the physics-based wideband model for the key component in the converter valve module is built, of which the parameters could be obtained through genetic algorithm. Second, the parasitic capacitances are obtained through a simplified boundary-element method according to the given structure of the $\pm $ 1100 kV converter valve. By combining wideband models for key components in the converter valve module and the parasitic capacitances of the valve tower, the integrated wideband model for the converter valve could be obtained. The systematic modelling method proposed in this paper could also be of reference value to the modelling of other large-scale complex high-voltage power-electronic equipment. Finally, the experiments for converter valve module and converter tower are carried out, and the corresponding results justified the effectiveness and correctness of the proposed wideband model for the converter valve tower.

A functional feature modeling method

With the advances in CAD technology, it has been increasingly convenient to model product shapes digitally. For example, in a feature-based parametric CAD system, the product shape could be parameterized and thus altered with the change of parameters. However, without a consistent and systematic CAD modeling method, CAD models are not robust enough to capture functional design knowledge and cope with design changes, especially functional changes. A poorly constructed CAD model could result in erroneous or inconsistent design that requires a lot of expertise, manpower and repetitive computation to rebuild a valid and consistent model. The situation can be worse if the model is complex. The gap between functional design considerations and procedural CAD modeling demands an integrated CAD modeling approach. This paper proposes a functional feature-based CAD modeling method to guide designers building CAD models that are valid and yet agile to represent functional design considerations. A case study is presented to demonstrate the feasibility of the proposed research.

Modelling of the rotational vibrations of the engine front-end accessory drive system: a generic method

To investigate the rotation vibration dynamics of the pulleys and the tension arms, and to estimate the vibrations of the belts and the slip ratio between the belt and the pulleys in the engine front-end accessory drive systems, a systematic modelling and analytical method is proposed for engine front-end accessory drive systems; this can be used for modelling engine front-end accessory drive systems with different layouts and different numbers of tensioners, including automatic and fixed tensioners. In the modelling, the rotational pulleys are classified as fixed-axis pulleys and moveable-axis pulleys (such as the pulley in the tensioner). Moreover, the belt spans are classified as the belt spans between the two fixed pulleys, and the belt spans adjacent to the pulley of a tensioner. The equations of motion for each type of pulley and the tension calculation equations for each type of belt span are developed. In this way, the equations of motion for all the pulleys and the tensioner arms can be obtained easily, irrespective of the layout of the tensioners. To obtain the dynamic rotational vibration responses of an engine front-end accessory drive system by the conventional Runge–Kutta method, high-efficiency algorithms or methods are also proposed for calculating the tangent-point coordinates between a belt and the adjacent pulleys and the belt length of the contact arc on one pulley. The proposed modelling and analysis methods are validated by modelling different layouts of the engine front-end accessory drive systems with different types and numbers of tensioners, and also by comparisons between the calculated dynamic vibration responses of the pulleys and the belts and the real experimental data.

A Knowledge Modeling Method for Computer Graphics Design & Production Based on Ontology

As one of the most critical stages of CG (Computer Graphics) industry, CG design & production needs the support of professional knowledge and practice experience of multidisciplinary. With the outstanding performance in knowledge sharing, integration and reuse, knowledge modeling could increase greatly the efficiency, reduce the cost and avoid repeated error in CG design & production. However, knowledge modeling of CG design & production differs greatly from those of other fields. On the one hand, it is similar to physical product design, which involves great deal of tacit knowledge such as modeling skills, reasoning knowledge and so on. On the other hand, as film, CG design & production needs a lot of unstructured description information. The heterogeneity between physical product and film makes knowledge modeling more complicated. Thus a systematic knowledge modelling method based on Ontology is proposed to aid CG design & production in this paper. CG animation knowledge is capture and organized from viewpoint of three aspects: requirements and design and production. The knowledge are categorized into static and dynamic knowledge, and Ontology is adopted to construct a hierarchic model to organize the knowledge, so as to offer a uniform communication semantic foundations for designers from different fields. Based on animation script, the CG design task model is proposed to drive the organization and management of different knowledge involved in CG design & production. Finally, we apply this method in the knowledge modeling of naked-eye animation design and production to illustrate effectiveness of this method.

A Metamodel for the Manufacturing Process Information Modeling

Since the manufacturing process information and their mutual relationship are complex and diverse, the clear and accurate description and modeling of manufacturing process information is a challenge in related study of manufacturing process. Considering the diversity of the process data, a four-layer framework for manufacturing process information modeling based on metamodel is proposed. A 4-tuple manufacturing process information metamodel is specified and the concepts and relationships of the manufacturing process information are represented by UML. Following the four-layer hierarchical modeling procedures in the framework, manufacturing process information can be modeled from metamodel to model in consistence with their data relationships and representations. An instance of information model regarding to machining process is developed for verification. This work provides a systematic and standardized modeling method and information expression mechanism for manufacturing process information modeling.