Error Harvest: A Method for System Design in Non- Ideal Conditions

Background: Piezoceramic materials have unique property which enables direct and bilateral conversion between mechanical and electrical energy. This ability facilitates significant miniaturisation of technology and opens many opportunities in design of new actuators and energy harvesters. Mathematical modelling of piezoelectric modules is notoriously hard due to complex constitutive equations defining mechanical and electrical energy conversion. Methods: The article presents research on a new synthesis method based on the Cauer’s method for electrical and mechanical system design. Mechanical damping is introduced with the use of Rayleigh’s approximation. A discrete electromechanical model is formed based on the Mason’s piezoelectric model. As an additional element of the research, a non-standard model analysis method using edge graphs and structural numbers is employed to investigate potential reductions in computational requirements for model analysis. Results: The electromechanical model analysis has shown an error of 5% in relation to the resonance target. The calculated peak in magnitude of displacement at the resonant frequency was well above the capability of a 3.5mm thick piezoelectric plate. The proposed non-standard method of analysis gave identical results in terms of obtained resonance frequencies. The calculated magnitude of vibrations was varying by 50 – 58%. Conclusions: The synthesis method presented in this paper allows an approximation of piezoelectric parameters of a real system based on the created mathematical model. Currently this method is subject to a considerable error in the determined vibration amplitudes of the system, but it allows a coarse approximation of the parameters while having a very limited number of input data. The additional method of analysis based on structural numbers offers a promising alternative to matrix calculations but requires a more thorough investigation of the computational power required to determine whether it can compete with existing algorithms.

Do secure information system design methods provide adequate modeling support?

Systematic design methods are widely diffused in academia, representing a standard in many engineering courses. Nevertheless, some flaws related to the conceptual design phase have been ascribed to these methods, especially concerning a non-comprehensive support to innovation. However, literature acknowledges several creativity-enhancing tools that can be conveniently combined with systematic design methods. In particular, many scholars refer to TRIZ, i.e. the well-known Russian problem-solving theory. Moreover, recent literature contributions propose some alternatives to the classical Functional Decomposition and Morphology (FDM), claiming to overcome some of the related flaws. One of them is the Problem Solution Network (PSN) approach, i.e. a systematic conceptual design method strongly based on a problem-solution co-evolutionary logic. In this context, our work aims at combining the potentialities of TRIZ with the benefits claimed for the PSN, by proposing a comprehensive integration procedure. Accordingly, this paper reports a detailed description of the proposal, where TRIZ tools are exploited to support problem solving within the PSN approach. Furthermore, an application is also reported where an industrial case study is presented to argue about possible potentialities and lacks of the proposed approach.

Optimization and design of heat recovery system for aviation

Multimode hybrid electric vehicles (HEVs) have been widely applied due to its high efficiency and excellent overall performance. However, the introduction of multimode HEVs makes it difficult to choose reasonable design factors (architectures, component parameters, and control strategies) and determine correct mode shift rules, which undoubtedly enhances design complexity. To improve the design efficiency and reduce screen difficulty of optimal multimode configurations, a systematic design method is proposed to generate, screen, and optimize multimode HEVs with a single planetary gear. Based on equivalent tree graph method, the novel architectures are first generated. Then, considering mode shift rules and component parameters, requirements of speed and torque in corresponding main mode and minimum shift rule graph of working modes are taken as constraints to complete configuration screening. Finally, the equivalent consumption minimization strategy considering the proposed mode shift rules is put forward to evaluate and optimize energy management. The numerical results show that fuel economy of optimized configurations is improved by at least 22.1%, which proves the effectiveness of proposed systematic design method. Furthermore, it reveals that the multimode configuration can achieve better fuel economy when adopting the appropriate mode shift rule and designing the right arrangement and number of clutches and brakes.

An improved system design method for cell-based energy storage systems: A combination of a constraint satisfaction problem with an extended Ragone plot

The present paper discusses a design method for a single‐input single‐output linear time‐invariant dual‐rate sampled‐data control system, where the sampling interval of a plant output is longer than the holding interval of a control input. In such a control system, intersample output oscillation, called ripple, can occur even if the sampled output converges to the reference input. In order to resolve this problem, two design methods have been proposed such that the existing sampled output response is maintained: an open‐loop system design method and a closed‐loop system design method. However, the open‐loop design method cannot be applied to systems for which the gain matrix of the control input is full rank. On the other hand, the closed‐loop design method can be used for such systems, but the sampled output response is maintained only in the steady state. The present study proposes a new closed‐loop design method in which ripples are eliminated and both the transient and steady‐state responses are maintained. The effectiveness of the proposed method is demonstrated through numerical examples. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Based on the meshing principle of silent chain and the structure of an automobile engine, timing silent chain system including involute tooth sprocket, guide plate, tension plate, and silent chain is designed in this paper. Dynamics analysis model is built, and vibration of the chain system is studied. The link tensile force and the contact force between link and other components, and the transmission error of crankshaft sprocket and exhaust camshaft sprocket are analyzed. The design and analysis method of the timing silent chain system is proposed. The wear elongation of the timing silent chain system is studied through the road test. The wear morphology of the link plate and pin working surface are observed. Analysis results show that the design method of the timing silent chain system is feasible. The major wear mechanism of the pin is fatigue wear, and the major wear mechanism of the link plate is fatigue wear and abrasive wear. The results of the dynamic simulation and the experimental research show that the design and analysis method of timing silent chain system is scientific and feasible, and wear resistant of the timing silent chain system is high.

A new system design and information modelling method based on a classification of comprehensive information models called four primitives is presented for the design and development of new generation of space launch vehicles, taking advantages of the latest technologies of information modelling of systems. Through an extensive investigation of vast amount of information generated during the design processes of launch vehicles in this research, the information of a design system is classified into four-primitive model or information domains, namely, product information, design process, simulation models and design problems. Based on this classification, a new design method based on four-primitive models is proposed, by which a launch vehicle system design process consists of two phases: meta-design phase and design phase. Furthermore, five steps are generated as a generic procedure to tackle the whole design process, and these include requirement decomposition and mapping, design information modelling, structuring of design pattern, execution of design pattern and utilization of design results. The proposed design method has been validated by applying the method in a design and comparing its key design performance measurement including launch capacity as case study validation examples of the research work.

Recently, a concept of damped outrigger system has been proposed for tall buildings. Structural characteristics and design method of this system were not sufficiently investigated to date. In this study, control performance of damped outrigger system for building structures subjected to seismic excitations has been investigated. And optimal design method of damped outrigger system has been proposed using multi-objective genetic algorithm. To this end, a simplified numerical model of damped outrigger system has been developed. State-space equation formulation proposed in previous research was used to make a numerical model. Multi-objective genetic algorithms has been employed for optimal design of the stiffness and damping parameters of the outrigger damper. Based on numerical analyses, it has been shown that the damped outrigger system control dynamic responses of the tall buildings subjected to earthquake excitations in comparison with a traditional outrigger system.

A robust experimental design method was developed using a response surface methodology and models to facilitate the development process of retinol solid lipid nanoparticles (SLNs). The SLNs were evaluated to determine how different parameters including lipid and surfactant affect size and encapsulation efficiency. This was conducted using factorial analysis and a robust design (RD) method was used to achieve optimal formulations. Two models were developed based on the RD principle and both mean and variance of the response characteristics were estimated functionally using the least squares method. They proved useful in formulation studies aiming to develop optimum by allowing a systematic and reliable design method. A model for maximizing the overall desirability represented by the geometric mean of all objectives was found to provide a better solution. The newly designed method provides useful information to characterize significant factors and obtain optimum formulations, thereby allowing a systematic and reliable design method.

Hardware Trojan attacks relate to malicious modifications of integrated circuits during design or manufacturing, involving untrusted design tools or components. Such modifications can lead to undesired behavior of integrated circuits or the appearance of hidden data leakage channels. There are various methods of classification, detection and prevention of hardware Trojans insertion. One approach to prevent of Trojans insertion is an obfuscation-based design approach. This approach is based on hiding the functional and structural properties of the design, which makes it difficult for an attacker to insert Trojans. The subject matter of research is an aggregation-based obfuscation method for electronic systems design. The goal of the work is to study the process of aggregation-based obfuscation of the electronic systems design. The main idea is that the development and connection phase of the reference monitor is performed in a trusted environment. Thus, an attacker will not be able to obtain its functionality and original structure. The relevance of the work lies in the fact that this approach prevents the possibility of functioning of hardware Trojans. The following tasks were solved in the work: development and study of an aggregation-based obfuscation algorithm for electronic systems design; implementation of the reference monitor presentation as a separate subsystem associated with the main design; experimental evaluation of the possibilities of the method. As a result of the work the aggregation-based obfuscation method for electronic systems design was demonstrated; reference monitor was presented as a separate subsystem associated with the main design; experimental evaluation of the possibilities of the method was demonstrated. The studies allow us to conclude: the obfuscation-based design approach is that the integrated circuit is modified, thus, the functional and structural properties of the design are hidden, which makes it difficult for an attacker to insert Trojans. Aggregation-based obfuscation considers the reference monitor as a separate subsystem associated with the main design.

The design problem of control systems for nonlinear plants with differentiated nonlinearity is considered. The urgency of this problem is caused by the big difficulties of practical design of nonlinear control systems with the help of the majority of known methods. In many cases, even provision by these methods of just stability of equilibrium point of a designing system represents a big challenge. Distinctive feature of the method of nonlinear control systems design considered below is the use of the nonlinear plants models represented in a quasilinear form. This form of the nonlinear differential equations exists, if nonlinearities in their right parts are differentiated across all arguments. The quasilinear model of the controlled plant allows reducing the design problem to the solution of an algebraic equations system, which has the unique solution if the plant is controlled according to the controllability condition provided in the article. This condition is similar to the controllability condition of the Kalman’s criterion. Procedure of the nonlinear control systems design on a basis of the plant’s quasilinear models is very simple. Practically, it is close to the known polynomial method of the linear control systems design. The equations of the nonlinear systems designed with application of the plant’s quasilinear models also can be represented in the quasilinear form.
 The basic result of this article is the proof of the theorem and the corollary from it about conditions of the asymptotical stability at whole of the equilibrium point of the nonlinear control systems designed on a basis of the plant’s quasilinear models. For the proof of the theorem and consequence, the properties of simple matrixes and known theorems of stability of the indignant systems of the differential equations are used. A way of the stability research of the equilibrium point of the quasilinear control systems based on the proved theorem is illustrated by numerical examples. Computer simulation of these systems verifies correctness of the hypoyhesis of the proved theorem.
 Obtained results allow applying the method of nonlinear systems design on a basis of the quasilinear models for creation of various control systems for plants in power, aviation, space, robotechnical and other industries.

Optimal design and operation method of integrated energy system based on stochastic scenario iteration and energy storage attribute evaluation

The northwest region is one of the regions with the richest solar energy resources and superior natural conditions in China. It is an ideal region for developing comprehensive solar thermal energy systems. In this paper, first of all, taking advantage of the characteristics of solar energy resource endowment in the northwest region, a comprehensive solar thermal energy system is designed for the northwest region. Secondly, a proposed integrated layout and design method for solar thermal integrated energy systems addresses the issue of deep coupling between capacity allocation and operational planning that exists in traditional integrated energy systems. Next, an integrated layout and design method for solar thermal integrated energy systems is proposed, which solves the problem of inaccurate matching between capacity allocation and operational planning in traditional integrated energy systems. Finally, in order to verify the superiority of the proposed solar thermal integrated energy system and its integrated layout and design method, a typical park in the northwest region of China is taken as an example for a case study and compared with the “following heat load” operation mode of traditional integrated energy systems, verifying that the proposed solar thermal integrated energy system and its integrated layout and design method are in good condition. The experimental simulation results show that the comprehensive layout and design method of the solar thermal integrated energy system in the northwest region proposed in this paper can effectively reduce system operating expenses, significantly reduce carbon emissions, realize the comprehensive utilization of electricity and heat, and effectively alleviate the energy shortage in remote areas.