Heterogeneous Physical Systems Research Articles

Immersive and interactive cyber-physical system (I2CPS) and virtual reality interface for human involved robotic manufacturing

Smart manufacturing promotes the demand of new interfaces for communication with autonomies such as big data analysis, digital twin, and self-decisive control. Collaboration between human and the autonomy becomes imperative factor for improving productivity. However, current human-machine interfaces (HMI) such as 2D screens or panels require human knowledge of process and long-term experience to operate, which is not intuitive for beginning workers or is designed to work with the autonomy. This study proposes a human interface framework of cyber-physical system (CPS) based on virtual reality, named as immersive and interactive CPS (I2CPS), to create an interface for human-machine-autonomy collaboration. By combination of data-to-information protocol and middleware, MTConnect and Robot Operating System (ROS), heterogeneous physical systems were integrated with virtual assets such as digital models, digital shadows, and virtual traces of human works in the virtual reality (VR) based interface. All the physical and virtual assets were integrated in the interface that human, autonomy, and physical system can collaborate. Applying constraints in the VR interface and deploying virtual human works to industrial robots were demonstrated to verify the effectiveness of the I2CPS framework, showing collaboration between human and autonomy: augmentation of human skills by autonomy and virtual robot teaching to generate automatic robot programs.

Hybrid quantum systems with circuit quantum electrodynamics

The rise of quantum information science has provided new perspectives on quantum mechanics, as well as a common language for quantum engineering. The focus on platforms for the manipulation and processing of quantum information bridges between different research areas in physics as well as other disciplines. Such a crossover between borders is well embodied by the development of hybrid quantum systems, where heterogeneous physical systems are combined to leverage their individual strengths for the implementation of novel functionalities. In the microwave domain, the hybridization of various quantum degrees of freedom has been tremendously helped by superconducting quantum circuits, owing to their large zero-point field fluctuations, small dissipation, strong nonlinearity and design flexibility. These efforts take place by expanding the framework of circuit quantum electrodynamics. Here, we review recent research on the creation of hybrid quantum systems based on circuit quantum electrodynamics, encompassing mechanical oscillators, quantum acoustodynamics with surface acoustic waves, quantum magnonics and coupling between superconducting circuits and ensembles or single spins. Hybrid quantum systems combine heterogeneous physical systems for the implementation of new functionalities at the quantum level. This article reviews recent research on the creation of hybrid quantum systems within the circuit quantum electrodynamics framework.

From fractal media to continuum mechanics

AbstractThis paper presents an overview of modeling fractal media by continuum mechanics using the method of dimensional regularization. The basis of this method is to express the balance laws for fractal media in terms of fractional integrals and, then, convert them to integer‐order integrals in conventional (Euclidean) space. Following an account of this method, we develop balance laws of fractal media (continuity, linear and angular momenta, energy, and second law) and discuss wave equations in several settings (1d and 3d wave motions, fractal Timoshenko beam, and elastodynamics under finite strains). We then discuss extremum and variational principles, fracture mechanics, and equations of turbulent flow in fractal media. In all the cases, the derived equations for fractal media depend explicitly on fractal dimensions and reduce to conventional forms for continuous media with Euclidean geometries upon setting the dimensions to integers. We also point out relations and potential extensions of dimensional regularization to other models of microscopically heterogeneous physical systems.

Modeling and Simulation of the PMSM-Precision Reducer System with Modelica

There is still lack of effective modeling and simulation method for complex electromechanical coupling system. Modelica is a multi-domain unified modeling language to solve the modeling and simulation problems of the complex and heterogeneous physical systems. Dymola is a Modelica-based modeling and simulation platform for the complex physical systems. In this paper, the dynamics model of the permanent magnet synchronous motor (PMSM)-precision reducer system is established using Lagrange-Maxwell equation. The simulation model of this system is set up with Modelica language. The simulation of the system is realized in Dymola. Results show that the system can respond to good static and dynamic characteristics under a given speed for different loads. The dynamics model of the PMSM-precision reducer system can be further used in system control and optimization. The proposed modeling and simulation method based on Modelica may be commonly applied to other complex electromechanical systems.

An Impact Equivalence Principle of Separating Control Designs for Networked Heterogeneous Affine Systems

In this paper, the new concept of generalized passivity is introduced to extend the concept of passivity to a dynamical system of any relative degrees and to quantify by a penalty coefficient the impact of its dynamics on the performance of its networked operation. It is shown that the knowledge of an upper bound on those penalty coefficients is sufficient to synthesize a network-level cooperative control and that, if all the physical systems are individually made to be generalized passive by appropriately designing their self-feedback controls, they can arbitrarily be placed at the nodes of a network-enabled cooperative control system. The proposed separation principle prescribes a completely modularized design methodology, and it unravels the complexity of analyzing and designing cooperative control of heterogeneous physical systems.

Modelling and simulation of PDE problems in Modelica

Modelica is a new object-oriented multi-domain modelling and simulation language used for solving large, complex and heterogeneous physical systems with differential algebraic equations (DAEs). Presently, there is no simulation support available in Modelica for solving partial differential equations (PDEs) problems. In this paper, based on the object-oriented idea, we present a method of consistent representation of PDE and DAE problems. The description of PDE problems in Modelica is introduced. Then the PDE model is transferred into DAE model with the method of lines, and is solved in MWorks simulation platform based on Modelica. To illustrate the application of our method, a heat conduction problem is modelled and simulated in Modelica.

A parallel boundary element formulation for determining effective properties of heterogeneous media

AbstractThis paper presents a parallel implementation of the boundary element method for MIMD computer architectures to determine the effective properties of two heterogeneous physical systems. The first physical system is comprised of spheres sedimenting in a viscous fluid at low Reynolds numbers. The effective property is characterized by the hindered settling function which is a measure of the average sedimentation velocity. The second physical system is a short‐fibre reinforced composite. The effective property for this system is the composite modulus. The determination of effective properties of heterogeneous media requires performing statistical analyses of several realizations of physical systems based on defining characteristics of the media. The boundary element method is particularly well suited for studying such systems because of the simplification in the discretization associated with the method. However, as the number of heterogeneities to be modeled is increased so are the computational demands. Parallel computation offers the opportunity to model systems of greater complexity. We discuss a parallel boundary element formulation based on the torus‐wrap mapping. In this approach, blocks of the coefficient matrix associated with the discretized boundary element equations are assigned to processors as opposed to more traditional parallel boundary element implementations where rows or columns are assigned to processors. The torus‐wrap mapping can be shown to minimize communication volume between processors during the LU factorization. Therefore, the present formulation scales well with increases in the number of processors.