Dynamic Design Method Research Articles

Dynamic Optimization Design of Cranes Based on Human–Crane–Rail System Dynamics and Annoyance Rate

The operators of overhead traveling cranes experience discomfort as a result of the vibrations of crane structures. These vibrations are produced by defects in the rails on which the cranes move. To improve the comfort of operators, a nine-degree-of-freedom (nine-DOF) mathematical model of a “human–crane–rail” system was constructed. Based on the theoretical guidance provided in ISO 2631-1, an annoyance rate model was established, and quantization results were determined. A dynamic optimization design method for overhead traveling cranes is proposed. A particle swarm optimization (PSO) algorithm was used to optimize the crane structural design, with the structure parameters as the basic variables, the annoyance rate model as the objective function, and the acceleration amplitude and displacement amplitude of the crane as the constraint conditions. The proposed model and method were used to optimize the design of a double-girder 100 t–28.5 m casting crane, and the optimal parameters are obtained. The results show that optimization decreases the human annoyance rate from 28.3% to 9.8% and the root mean square of the weighted acceleration of human vibration from 0.59 m/s2to 0.38 m/s2. These results demonstrate the effectiveness and practical applicability of the models and method proposed in this paper.

Design of Dynamic Reconfigurable Structure Based on Integrated Filter Banks

In electronic confrontation, radar confrontation is an important part. Various radars widely used in modern warfare are the most important equipment in the field of information acquisition and precision guidance. Especially in the vast battle space, in order to achieve timely, accurate and comprehensive access to various target information, the role of radar is irreplaceable. Especially in the vast battle space, the role of radar is irreplaceable in order to achieve timely, accurate and comprehensive access to various target information. Therefore, in the war, it will not be able to protect their own survival and play combat effectiveness if not having the radar's ability to fight. At this time, that is the need for radar equipment in time to detect radar exposure, rapid measurement of radar signal parameters and identify threat signals, and targeted to do the implementation of interference or the implementation of technical attacks. In order to extract the parameters of the received signal to facilitate the subsequent research and analysis, this paper deduces the structure of the integrated filter bank in detail, and gives the reconfigurable filter bank structure design method, under the condition of accurate reconstruction of the signal. Based on the analysis of the design and calculation complexity of the filter bank structure, the dynamic reconfigurable design method con-sumes less hardware resources and wide application range, and the simulation structure also verifies the correctness and flexibility of the structure.

Approximation-based decentralized adaptive tracking for a class of arbitrarily switched interconnected non-affine nonlinear systems

This paper investigates the decentralized adaptive tracking problem for a class of uncertain switched interconnected non-affine nonlinear systems under arbitrary switching. Based on dynamic surface design and common Lyapunov function method, an adaptive approximation design methodology for the decentralized adaptive tracking is proposed to ensure that the total controlled closed-loop system is asymptotically bounded and the local output tracking performance is maintained within preselected time-varying bounds independent of switched interactions. For this decentralized tracker design, an auxiliary nonlinear function is introduced to overcome the interaction problem of unknown switched nonlinearities. Contrary to the related results in the literature, the proposed new design approach firstly deals with the switched interactions among switched subsystems in the non-affine form, ensures the transient performance at switching instants within preselected bounds, and does not require the information on the signs of control gain functions. A simulation example is provided to show the effectiveness of the resulting decentralized control system.

Fault detection of a sandwich system with dead-zone based on robust observer

Non-smooth sandwich systems with dead-zone widely exist in the real engineering applications. For accurately detecting its faults, a novel robust observer has been proposed in this paper. With the consideration of the model uncertainties, disturbances, and switching error which specially belongs to the system, the so-called general disturbance is defined. After that, the conventional dynamic robust observer design method can be applied to the system. Then, for saving the computing time and effectively reducing the effect of the disturbances to the residual, the main frequencies of the disturbances have been identified by the spectrum analysis of the residual created by the conventional observer and the zeros assignment methodology has been applied to get one feedback matrix of the robust observer. Finally, the rest of the feedback matrices of the robust observer can be obtained by solving an optimal problem with H∞,F/H−,F as the minimizing object. For verifying the effectiveness of this novel robust observer, the comparison between the proposed robust non-smooth scheme and the conventional method has been made. The final results show that the proposed robust fault detection approach can detect the actuator and sensor faults of the system more accurately and timely with a lower missing and false alarm rates comparing with the conventional one.

Dynamic similarity design method for an aero-engine dualrotor test rig

This paper presents a dynamic similarity design method to design a scale dynamic similarity model (DSM) for a dual-rotor test rig of an aero-engine. Such a test rig is usually used to investigate the major dynamic characteristics of the full-size model (FSM) and to reduce the testing cost and time for experiments on practical aero engine structures. Firstly, the dynamic equivalent model (DEM) of a dual-rotor system is modelled based on its FSM using parametric modelling, and the first 10 frequencies and mode shapes of the DEM are updated to agree with the FSM by modifying the geometrical shapes of the DEM. Then, the scaling laws for the relative parameters (such as geometry sizes of the rotors, stiffness of the supports, inherent properties) between the DEM and its scale DSM were derived from their equations of motion, and the scaling factors of the above-mentioned parameters are determined by the theory of dimensional analyses. After that, the corresponding parameters of the scale DSM of the dual-rotor test rig can be determined by using the scaling factors. In addition, the scale DSM is further updated by considering the coupling effect between the disks and shafts. Finally, critical speed and unbalance response analysis of the FSM and the updated scale DSM are performed to validate the proposed method.

Optimal dynamic design of planar mechanisms using teaching–learning-based optimization algorithm

A two-stage optimization method for optimal dynamic design of planar mechanisms is presented in this paper. For dynamic balancing, minimization of the shaking force and the shaking moment is achieved by finding optimum mass distribution of mechanism links using the equimomental system of point-masses in the first stage of the optimization. In the second stage, their shapes are synthesized systematically by closed parametric curve, i.e. cubic B-spline curve corresponding to the optimum inertial parameters found in the first stage. The multi-objective optimization problem to minimize both the shaking force and the shaking moment is solved using evolutionary optimization algorithm – “Teaching-learning-based optimization (TLBO) algorithm”. The computational performance of TLBO algorithm is compared with another evolutionary optimization algorithm, i.e. genetic algorithm.

Dynamic design method for deep hard rock tunnels and its application

Numerous deep underground projects have been designed and constructed in China, which are beyond the current specifications in terms of scale and construction difficulty. The severe failure problems induced by high in situ stress, such as rockburst, spalling, damage of deep surrounding rocks, and time-dependent damage, were observed during construction of these projects. To address these problems, the dynamic design method for deep hard rock tunnels is proposed based on the disintegration process of surrounding rocks using associated dynamic control theories and technologies. Seven steps are basically employed: (i) determination of design objective, (ii) characteristics of site, rock mass and project, and identification of constraint conditions, (iii) selection or development of global design strategy, (iv) determination of modeling method and software, (v) preliminary design, (vi) comprehensive integrated method and dynamic feedback analysis, and (vii) final design. This dynamic method was applied to the construction of the headrace tunnels at Jinping II hydropower station. The key technical issues encountered during the construction of deep hard rock tunnels, such as in situ stress distribution along the tunnels, mechanical properties and constitutive model of deep hard rocks, determination of mechanical parameters of surrounding rocks, stability evaluation of surrounding rocks, and optimization design of rock support and lining, have been adequately addressed. The proposed method and its application can provide guidance for deep underground projects characterized with similar geological conditions.

Hierarchical Blind Interference Alignment Over Interference Networks With Finite Coherence Time

We investigate a blind interference alignment (BIA) scheme through staggered antenna switching over various interference networks (e.g., broadcast channel, interference channel, and cellular networks) with realistic channel assumptions. In existing BIA, the coherence time of channel is assumed to be long enough, but that may not always be true in realistic scenarios. Therefore, we propose a dynamic supersymbol design method which can construct a supersymbol with limited symbol extension that is determined by the coherence time of channel. It is demonstrated that the supersymbol block length can be reduced significantly by aligning interferences in a hierarchical manner, referred to as hierarchical BIA. The key idea of hierarchical BIA is to align interferences in groups and to use the same supersymbol structure between groups, producing aligned inter-group interferences without inner-group interference. Consequently, it is observed that with a given coherence time the proposed dynamic supersymbol design that exploits hierarchical BIA achieves higher degrees of freedom than the conventional method.

Modal Strain Based Method for Dynamic Design of Plate-Like Structures

Design optimization of dynamic properties, for example, modal frequencies, can be of much importance when structures are exposed to the shock and/or vibration environments. A modal strain based method is proposed for fast design of natural frequencies of plate-like structures. The basic theory of modal strains of thin plates is reviewed. The capability of determining the highly sensitive elements by means of modal strain analysis is theoretically demonstrated. Finite element models were constructed in numerical simulations. Firstly, the application of the proposed method is conducted on a central-massed flat plate which was topologically optimized by the Reference. The results of modal strain analysis at the first mode have good agreement with the results from the topology optimization. Furthermore, some features of the strain mode shapes (SMSs) of the flat plate are investigated. Finally, the SMSs are applied to the optimization of a stiffened plate. Attention is focused on the distributions of the SMSs of the stiffeners, which also shows good agreement with the results from the topology optimization in the previous study. Several higher orders of SMSs are extracted, which can visualize the most sensitive elements to the corresponding modal frequency. In summary, both the theory and simulations validate the correctness and convenience of applying SMSs to dynamic design of plate-like structures.

Axiomatic Design Method for the Hydrostatic Spindle with Multisource Coupled Information

The strong coupling among different parts such as bearings, seals, and windings, which are associated with different fields such as tribology, dynamics, and fluid dynamics, should be addressed to design a high-performance hydrostatic spindle. For decoupling and integrating all multisource information, the axiomatic design is using to address the design problems. A mapping with four levels of functional requirements and design parameters (DPs) was developed for the hydrostatic spindle design, and 19 DPs for the physical parts of the hydrostatic motorized spindle were integrated in several parts such as rotor, bearing, and winding. A 19×19 design matrix was built. Using the design matrix, a flow chart for the dynamics design method coupled with multisource information was obtained. The design of a hydrostatic spindle was completed, and the major requirements were assessed. The results show that the dynamics design process and hydrostatic spindle can be optimized using the axiomatic design method.

Fault detection for sandwich systems with hysteresis based on robust observer

In the real application, realizing the accurate fault prediction of non-smooth sandwich system with hysteresis which widely exists in the real engineering systems is of great importance. Therefore, a novel dynamic robust observer is proposed in this paper. First, the non-smooth sandwich system with hysteresis is transformed into a system in which conventional dynamic robust observer design method can be applied by converting the non-smooth item into a general disturbance. Then, by zeros assignment and minimizing the H∞,F/H−,F indicator on the basic operation zone, the feedback matrices of this observer can be obtained. After that, the simulation results are presented. The comparison between the proposed robust non-smooth scheme and the conventional method demonstrated that the proposed robust fault detection approach can detect the actuator and sensor faults accurately and quickly which the conventional observer can not detect the faults at all. Moreover, the missing and false alarms are effectively reduced by the robust observer.

고속프레스의 다이나믹 시스템 및 방진시스템 설계에 관한 연구

In a high-speed press, numerous moving links are interconnected and each link executes a constrained motion at high speed. As a consequence, high-level dynamic unbalance force and unbalance moment are transmitted to the main frame of the press, which results in unwanted vibration and significantly degrades manufacturing accuracy. Dynamic unbalance force and unbalance moment inevitably transmits high-level vibrational force to the foundation on which the press is installed. Minimizing the vibrational force transmitted to the foundation is critical for the protection of both the operators and the surrounding structures. The whole task should be carried out in two steps. The first step is to reduce dynamic unbalance based upon kinematic and dynamic analyses. The second step is to design and build an optimal vibration isolation system minimizing the vibrational force transmitted to the foundation. Firstly, the dynamic design method is presented to reduce dynamic unbalance force and moment. For this a 3D CAD software was utilized and a computer program was written to compute dynamic unbalance force and moment. Secondly, the design method for vibration isolation system is presented. The method for designing coil springs and viscous dampers are explained in detail.

Containment control of networked autonomous underwater vehicles: A predictor-based neural DSC design

This paper investigates the containment control problem of networked autonomous underwater vehicles in the presence of model uncertainty and unknown ocean disturbances. A predictor-based neural dynamic surface control design method is presented to develop the distributed adaptive containment controllers, under which the trajectories of follower vehicles nearly converge to the dynamic convex hull spanned by multiple reference trajectories over a directed network. Prediction errors, rather than tracking errors, are used to update the neural adaptation laws, which are independent of the tracking error dynamics, resulting in two time-scales to govern the entire system. The stability property of the closed-loop network is established via Lyapunov analysis, and transient property is quantified in terms of L2 norms of the derivatives of neural weights, which are shown to be smaller than the classical neural dynamic surface control approach. Comparative studies are given to show the substantial improvements of the proposed new method.

Dynamic Bio-sensing Process Design in Mobile Wellness Information System for Smart Healthcare

As the wireless communication technologies of data communication media and biosensors to measure bioengineering signals of a human body are advanced, the wearable mobile computing technology is utilized and is developed in various areas such as personal healthcare, and care-giving for senior citizens and sports activity. This study suggests a customized healthcare service by means of wellness clothing that includes digital yarns and bio sensors. Wellness clothing is utilized to acquire, analyze, and present bio-engineering data including ECG, respiration, acceleration, and body temperature as part of the wellness information system framework. The conventional process configuration of biometric information system performs the fixed process without changing statically and consistently after the system is starting. However, the static configuration of these processes appears the inefficient and inconvenient applications of the mobile wellness information system in the mobile computing environment. This work proposes the dynamic process design and execution method as a way to overcome these inefficient static processes. As well as, it proposes a bio-information framework and service platform applicable for light-weighting mobile systems such as wearable computing, wellness system, etc.

Modal-based mixed vibration control for uncertain piezoelectric flexible structures

H-infinity norm relates to the maximum in the frequency response function and H-infinity control method focuses on the case that the vibration is excited at the fundamental frequency, while 2-norm relates to the output energy of systems with the input of pulses or white noises and 2-norm control method weighs the overall vibration performance of systems. The trade-off between the performance in frequency-domain and that in time-domain may be achieved by integrating two indices in the mixed vibration control method. Based on the linear fractional state space representation in the modal space for a piezoelectric flexible structure with uncertain modal parameters and un-modeled residual high-frequency modes, a mixed dynamic output feedback control design method is proposed to suppress the structural vibration. Using the linear matrix inequality (LMI) technique, the initial populations are generated by the designing of robust control laws with different H-infinity performance indices before the robust 2-norm performance index of the closed-loop system is included in the fitness function of optimization. A flexible beam structure with a piezoelectric sensor and a piezoelectric actuator are used as the subject for numerical studies. Compared with the velocity feedback control method, the numerical simulation results show the effectiveness of the proposed method.

The effects of adopting the innovative dynamic product design method on the performance of students of different learning styles

The innovative dynamic product design (IDPD) method has been proposed and proven to be effective in diversifying how designers think. To further understand the influence of learning styles on the applications of the IDPD method, this study recruited student designers to actually employ this method in designing products, and the effects of the method on the performance of the students with different learning styles were analysed. This study contains three stages. In the first stage, we divided the 16 industrial design students into 4 groups according to Kolb's learning style inventory, and every group was required to attend a product development workshop and apply the IDPD method. In the second stage, we conducted a questionnaire survey on the users who had used the products of the students and evaluated the performance of the student groups. In the third stage, the students evaluated and provided feedback regarding the IDPD method. The research results showed that the products yielded significantly different user evaluations based on student learning style: the accommodators garnered the highest score, followed by the assimilators, divergers, and convergers. The information processing method of accommodators and convergers were identically active experimentation. However, the difference in information perceptions of these two types of learners resulted in considerable difference in evaluations on design works. User evaluations on works by divergers and assimilators had little difference, which indicated that regardless of the methods to receive information the reflective observation information processing method did not pose extreme evaluations on student performance.

Reduced record method for efficient time history dynamic analysis and optimal design

Time history dynamic structural analysis is a time consuming procedure when used for large- scale structures or iterative analysis in structural optimization. This article proposes a new methodology for approximate prediction of extremum point of the response history via wavelets. The method changes original record into a reduced record, decreasing the computational time of the analysis. This reduced record can be utilized in iterative structural dynamic analysis of optimization and hence significantly reduces the overall computational effort. Design examples are included to demonstrate the capability and efficiency of the Reduced Record Method (RRM) when utilized in optimal design of frame structures using meta- heuristic algorithms.

Fuzzy Controllers for Nonaffine-in-Control Singularly Perturbed Switched Systems

This paper investigates the problem of fuzzy controller design for nonaffine-in-control singularly perturbed switched systems (NCSPSSs). First, the NCSPSS is approximated by Takagi-Sugeno (T-S) models which include not only state but also control variables in the premise part of the rules. Then, a dynamic state feedback controller design method is proposed in terms of linear matrix inequalities. Under the controller, stability bound estimation problem of the closed-loop system is solved. Finally, an example is given to show the feasibility and effectiveness of the obtained methods.

Zone Design of Tandem Loop AGVs Path with Hybrid Algorithm

AGV has been widely used in flexible manufacturing system. In order to prevent AGV collision for a workshop with complicated and crossover AGV paths, a dynamic tandem loop AGV path design method is proposed. A mathematical model for tandem loop AGV path optimization is established with the goal to minimize material flow between different loops of AGV path. AGV load balancing and material flow-within-loop balancing between different loops are taken as constraints. A hybrid genetic simulated annealing algorithm is proposed for optimization. The optimal scheme of allocating workstations to different tandem loops can be obtained finally. Case studies results, including an air conditioner assembly workshop AGV path design, have shown that the method is feasible and effective.

Axiomatic Design Method for the Rotor Dynamics of the Multi-source Information Coupled High-speed Turbopump

The strong coupling design information from the different parts(such as bearings, seals, balance disc, etc) and the different fields(such as tribology, dynamics, fluid dynamics, etc) need to be addressed for finishing the design of an advanced high-speed turbopump rotor dynamics. For decoupling and integrating all of the multi-source information, the design method based on the axiomatic design method is proposed. The four levels of the functional requirements(FRs) and the design parameters(DPs) mapping for the high-speed turbopump rotor dynamics design process is developed, and the 14 DPs are integrated in the 5 parts of the rotor system, such as journal bearings, seal, thrust bearing, balance disc, and shaft. The 14×14 design matrix is built. With the design matrix, the flow chart for the multi-source information coupled dynamics design method is obtained. A design case for a turbopump rotor dynamics is completed, and the major requirements are assessed. The results show the axiomatic design method for the high-speed turbopump rotor optimizes the dynamics design process and results.