Robust Design Research Articles

Constrained control for electromagnetic levitation system with matched and mismatched uncertainties via robust optimal design

Constrained control for electromagnetic levitation system with matched and mismatched uncertainties via robust optimal design

Electric Vehicle Steering System Fuzzy Modeling and Controller Design

Electric vehicle (EV) steering control becomes much more important in many senses such as driving comfort and safety. Unlike the traditional internal combustion engine powered vehicles that possess only one control input related to the steering wheel, the so‐called direct yaw moment control is yet another control input in EVs thanks to the dispersedly located in‐wheel motors. In view of controller design crucially depending on a proper mathematical model, this paper first focuses on the modeling of EV steering system with uncertainty in the system considered for the latter robust controller design. Then a Takagi‐Sugeno (T‐S) fuzzy model is obtained based on the EV's model, which is capable of varying vehicle velocity in a range. Finally, a robust controller with inputs constraint is designed based on the model, and the effectiveness is verified by computer simulations. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Downed wood removal effects on survival and site fidelity of woodrats in a California oak woodland

AbstractOwing to the increasing intensity and frequency of wildfires in the western United States, the removal of woody debris (downed dead wood and snags) from fire‐prone landscapes is being evaluated for wildfire mitigation. Consequently, the study of the ecological value of coarse woody debris to sustain dependent species has become of foremost importance. From 2004–2009, we used a before‐after control‐impact (BACI) study design to assess the effects of downed wood removal on a population of big‐eared woodrats (Neotoma macrotis) in an oak woodland (Quercus spp.) in coastal‐central California, USA. Using Pollock's robust design mark‐recapture analyses (with 12 primary capture occasions represented by trapping each spring and fall, and secondary occasions composed of 3 trap nights), we estimated survival and emigration rates. Further, applying mixed‐effects models, we evaluated the effects of 7 habitat attributes on woodrat abundance and reproduction. Following the experimental removal of downed wood from the 11 randomly selected treatment plots, woodrat survival was higher (P = 0.013), and emigration was lower (P = 0.007) among 11 control plots on which downed wood was retained. Woodrat abundance within plots was best predicted by stem density, demonstrating positive demographic associations with habitat complexity. Plot‐level reproductive success (i.e., the presence of juveniles within a plot during spring) was more likely with increasing snag density. These findings indicate that snags and downed dead wood are key components of high‐quality habitat for big‐eared woodrats. Management of woody debris to mitigate wildfire risk should consider the ecological value of this habitat attribute for big‐eared woodrats and other dependent species.

Development of a Six-Degree-of-Freedom Analog 3D Tactile Probe Based on Non-Contact 2D Sensors.

In this paper, a six-degree-of-freedom analog tactile probe with a new, simple, and robust mechanical design is presented. Its design is based on the use of one elastomeric ring that supports the stylus carrier and allows its movement inside a cubic measuring range of ±3 mm. The position of the probe tip is determined by three low-cost, noncontact, 2D PSD (position-sensitive detector) sensors, facilitating a wider application of this probe to different measuring systems compared to commercial ones. However, several software corrections, regarding the size and orientation of the three LED light beams, must be carried out when using these 2D sensors for this application due to the lack of additional focusing or collimating lenses and the very wide measuring range. The development process, simulation results, correction models, experimental tests, and calibration of this probe are presented. The results demonstrate high repeatability along the X-, Y-, and Z-axes (2.0 µm, 2.0 µm, and 2.1 µm, respectively) and overall accuracies of 6.7 µm, 7.0 µm, and 8.0 µm, respectively, which could be minimized by more complex correction models.

Nucleic acid-loaded poly(beta-aminoester) nanoparticles for cancer nano-immuno therapeutics: the good, the bad, and the future.

Immunotherapy has emerged as a promising approach to cancer treatment, offering improved survival rates and enhanced patients' quality of life. However, realizing the full potential of immunotherapy in clinical practice remains a challenge, as there is still plenty of room for modulating the complexity of the human immune system in favor of an antitumor immunogenicity. Nanotechnology, with its unique properties, holds promise in augmenting the efficacy of cancer immunotherapies in biotherapeutic protection and site- and time-controlled delivery of the immune modulator biologicals. Polymeric nanoparticles are promising biomaterials among different nanocarriers thanks to their robustness, versatility, and cost-efficient design and production. This perspective paper overviews critical concepts in nanometric advanced delivery systems applied to cancer immunotherapy. We focus on a detailed exploration of the current state of the art and trends in using poly(beta-aminoester) (pBAE) polymers for nucleic acid-based antitumor immunotherapies. Through different examples of the use of pBAE polymers reported in the literature, we revise the main advantages these polymers offer and some challenges to overcome. Finally, the paper provides insights and predictions on the path toward the clinical implementation of cancer nano-immunotherapies, highlighting the potential of pBAE polymers for advancements in this field.

3D Architecting triple gradient graphene-based fiber electrode for high-performance asymmetric supercapacitors

High-performance fibrous architectures and controllable fabrication methods for active nanomaterials are fundamental in the development of fiber-based supercapacitors (FSCs). Herein, we rationally designed a triple gradient structured fibrous electrode based on three-dimensional (3D) architectural approach with Ni3S2 nanoflakes (Ni3S2 NFs) in situ growth on Ni-coated graphene fiber (Ni3S2-NiGFs) for highly energy-dense asymmetric supercapacitors. Remarkably, the Ni-metal coating imparted the Ni3S2-NiGFs exceptional electrical conductivity (619.8 S cm−1), mechanical strength (335.0 MPa), and flexibility without significantly compromising its density. Moreover, the unique 3D interconnected ultrathin Ni3S2 NFs significantly increase the contact area between the electrode and the electrolyte solution, providing abundant redox activity to facilitate ion transport and accumulation. Therefore, the fibrous electrode showcased a remarkable areal specific capacitance of 1387.6 mF cm−2 at 3 mA cm−2 in 3 M KOHaq electrolyte, while its asymmetric FSCs delivered an impressive areal energy density of 15.6 μW h cm−2 at power density of 1.0 mW cm−2 along with durable cycle life (86.7 % of the initial specific capacitance retention over 10,000 cycles). In summary, the featured work provides a facile but robust electrode design to realize highly energy-dense flexible energy storage devices for next-generation wearable industries.

A study on robust design of cruciform torsional beam/cantilever beam

The electro-thermal actuator of a micro-electromechanical system (MEMS) has high power consumption and low response speed. To overcome this shortcoming, a steady state mechanism of cross torsion beam/cantilever beam is proposed in conjunction with the micro-electro-thermal actuator. Through the analysis of the structure and working principle of the cross torsion beam/cantilever beam, as well as the randomness analysis of its design variables and noise factors, the robust design is carried out, and the algorithm program of the stochastic model is written to solve the robust design model. The results show that the robust design method can not only ensure that the cantilever beam will not collapse excessively after the whole mechanism is released from the air but also ensure the robustness of the design solution when the design variables and noise factors change.

6σ Robust Lightweight Design of the GIL/GIS Bus Based on Co‐Simulation of Insulation, Current Flow, and Mechanical Stress

GIL/GIS bus is widely used in the field of power transmission and distribution, and the demand for lightweight is becoming more and more prominent. To reduce the weight of the bus and ensure the safety and reliability of the structure, a new 6σ robust design method of the GIL/GIS bus based on electric‐thermal‐mechanical co‐simulation is proposed. Taking a 550 kV/5000A bus as the initial structure, considering the uncertainty of product size and performance, a 6σ robust lightweight model of bus insulation electric field strength, current temperature rise, and mechanical stress multi‐performance co‐simulation is established. The finite element numerical calculation method is used to calculate and analyze the performance parameters of the bus. The Kriging surrogate model is used to form the response surface, and the optimal bus structure is obtained by genetic algorithm. The results show that after the robustness optimization, the performance of the bus meets the design requirements, the weight per meter decreased from 65.11 to 39.12 kg, and the lightweight effect is remarkable. Compared with the traditional deterministic optimization design, the reliability of the structure is improved. The new method of the GIL/GIS bus lightweight design proposed in this study has high feasibility and application prospects, which can provide new ideas for the development of gas‐insulated electrical equipment. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Impact of Hardware Impairment on the Joint Reconfigurable Intelligent Surface and Robust Transceiver Design in MU-MIMO System

Reconfigurable intelligent surface (RIS) is a revolutionary passive radio technique to facilitate capacity enhancement beyond the current massive multiple-input multiple-output (MIMO) transmission. However, the potential hardware impairment (HWI) of the RIS usually causes inevitable performance degradation and the amplification of imperfect CSI. These impacts still lack full investigation in the RIS-assisted wireless network. This paper developed a robust joint RIS and transceiver design algorithm to minimize the worst-case mean square error (MSE) of the received signal under the HWI effect and imperfect channel state information (CSI) in the RIS-assisted multi-user MIMO (MU-MIMO) wireless network. Specifically, since the proposed robust joint RIS and transceiver design problem yields non-convex characteristics under severe HWI, an iterative three-step convex algorithm is developed to approach the optimality by relaxation and convex transformation. Compared with the state-of-the-art baselines that ignore the HWI, the proposed robust algorithm inhibits the destruction of HWI while raising the worst-case MSE effectively in several numerical simulations. Moreover, due to the properties of the HWI, the performance loss is notable under the magnification of the number of reflected elements in the RIS-assisted MU-MIMO wireless network.

EHFE refinement and extension for variable physical Earth radiation in spacecraft uncertainty thermal analysis

Spacecraft uncertainty thermal analysis is an important part of ensuring robust and reliable spacecraft thermal control system design. The calculation of the Earth external heat flux is an important part of it, however, the current model for calculating the Earth external heat flux is the constant physical Earth radiation model. In this paper, a model of the Earth’s variable physical radiation is developed based on the long-term averaging method. We refine and extend the application of the external heat flux expansion (EHFE) formula to accommodate our proposed model. This study further includes an uncertainty analysis of Earth radiative external heat flux, utilizing the enhanced EHFE formula in the context of a representative spacecraft. We provide statistical data, such as mean values, standard deviation, and probability density functions, derived from our analysis. The augmented EHFE formula, when properly generalized, can be applied to compute the celestial body’s variable physical radiative external heat flux affecting the spacecraft. This methodological advancement offers theoretical underpinning for the thermal design of spacecraft intended for deep space exploration.

Robust Regularization Design of Graph Neural Networks Against Adversarial Attacks Based on Lyapunov Theory

Robust Regularization Design of Graph Neural Networks Against Adversarial Attacks Based on Lyapunov Theory

Robust Transmission Design for RIS-Assisted Multi-Cluster Wireless Powered Communications With Hardware Impairments

Robust Transmission Design for RIS-Assisted Multi-Cluster Wireless Powered Communications With Hardware Impairments

Human Leukocyte Antigen Alleles (HLA-A, HLA-B, and HLA-DRB1) are associated with Acute Lymphoblastic Leukemia (ALL) : A Case-Control Study in a Sample of Iranian Population.

This study seeks to elucidate the association between HLA-A, HLA-B, and HLA-DRB1 alleles and their relative risk contributions to ALL within an Iranian cohort. Utilizing a robust case-control design, this research involved 71 ALL patients and 71 age and sex-matched healthy individuals. Genotyping of specified HLA alleles was performed using the advanced PCR-SSP technique. Our findings reveal a marked increase in the prevalence of the HLA-DRB1*04 allele among patients diagnosed with ALL compared to the control group (P<0.027). Conversely, the alleles HLA-A*26 (P=0.025), HLA-A*33 (P=0.020), and HLA-DRB1*03 (P=0.035) were observed at significantly reduced frequencies within the patient population. Our findings highlight HLA-DRB1*04 as a potential genetic marker for increased susceptibility to ALL, while HLA-A*26, HLA-A*33, and HLA-DRB1*03 emerge as protective factors.

Towards robust fault detection for Takagi–Sugeno nonlinear systems

This paper addresses robust fault detection observer design for a class of discrete-time Takagi–Sugeno nonlinear systems. A novel design method is presented based on finite-frequency H−/H∞ indices and peak-to-peak analysis. The finite-frequency H− and H∞ indices are utilized to characterize fault sensitivity and disturbance robustness, respectively. The peak-to-peak analysis is used to derive a dynamic threshold. An iterative algorithm is further developed to reduce conservatism. Theoretical proof shows that the performance of the proposed method is not worse than some existing works. Simulation results demonstrate the validity and viability of the proposed method.

UAV-Aided Secure Communication With Imperfect Eavesdropper Location: Robust Design for Jamming Power and Trajectory

UAV-Aided Secure Communication With Imperfect Eavesdropper Location: Robust Design for Jamming Power and Trajectory

Orthogonal array and artificial neural network approach for sustainable cutting optimization machining of 17-4 PH steel under CNC wet turning operations

Sustainable manufacturing strives to increase output while minimizing resource usage, costs, and environmental impact. Tool longevity is crucial, considering material, power, and resource consumption. Challenges like chip removal, heat, and friction necessitate effective solutions. Cutting fluids, like rice bran oil, reduce temperatures, friction, and enhance tool life and surface quality. Research focuses on using rice bran oil with a TiAlN tipped tool to minimize friction and cutting forces. Taguchi's robust design and L-9 orthogonal array reduce experimental trials. Controllable factors include speed, feed, depth of cut, and rice bran oil flow rate, with surface roughness as the performance metric. Taguchi analysis improves turning performance, particularly with 17-4 PH stainless steel. Rice bran oil reduces frictional forces, enabling improved surface quality across all samples, promoting sustainability. Surface roughness (Ra) is notably influenced by feed rate and rice bran oil, contributing 58.06% and 49.5%, respectively. This research underscores the potential of optimizing cutting fluid and process parameters to enhance sustainability in manufacturing.

Molding robust S-box design based on linear fractional transformation and multilayer Perceptron: Applications to multimedia security

This study introduces a novel and refined approach for generating exceptionally efficient S-boxes. The proposed methodology employs a hybrid approach that combines linear fractional transformation (LFT) with a multilayer perceptron (MLP) architecture. This method makes use of a perceptron with three layers: input, hidden, and output. Each layer's neuron count is fine-tuned to conform to the S-box layout. In addition, a threshold nonlinear transformation is utilized to increase nonlinearity, and a novel algorithm for boosting nonlinearity is introduced. The utilization of both LFT and MLP approaches has led to the development of S-boxes that possess nearly ideal average nonlinearity values, surpassing those that have been presented in literature. Notably, one S-box achieved an exceptional nonlinearity score of 114.50. Furthermore, to demonstrate how well the S-box works, this study also employs it in an image encryption application.

Experimental evaluation and numerical investigation on the anti-collapse performance of beam-to-column connections in the minor-axis direction

This study examined the effects of structural resistance in both major- and minor-axis directions on the anti-collapse performance of a fully bolted composite frame. Current research in the field has focused predominantly on the anti-collapse performance of H-columns in the major-axis direction, potentially hindering accurate determination of anti-collapse transmission path within a structure. Herein, monotonic static loading experiments were conducted on two substructures in the minor-axis direction: one equipped with welded flange and bolted web connections and the other with fully bolted connections. The ductility development curve, dynamic collapse response curve, and resistance mechanism correlation curve were employed to evaluate the test results. Fully bolted connections exhibited superior nonlinear rotation capacity, which is essential for the development of a structure's catenary resistance The failure mechanisms and resistance development processes of the structures were reproduced using the ABAQUS/Explicit dynamic quasi-static modeling technique. A full-scale finite element model was developed for the frame with fully bolted connections loaded in the minor-axis direction. This research will contribute to the robust design of fully bolted structural frames that considers the effects of the column stiffness, thickness of the splicing cover plate, number of bolt rows, and bolt apertures of flange connections on deformation and resistance to loading in the minor-axis direction.

Joint Hybrid Beamforming Design for Millimeter Wave Amplify-and-Forward Relay Communication Systems

Hybrid beamforming (HBF) has been regarded as one of the most promising technologies in millimeter Wave (mmWave) communication systems. In order to guarantee the communication quality in non-line-of-sight (NLOS) scenarios, joint HBF design for the mmWave amplify-and-forward (AF) relay communication system is studied in this paper. The ideal case is first considered where the mmWave half-duplex (HD) AF relay system operates with channel state information (CSI) accurately known. In order to tackle the non-convex problem, a manifold optimization (MO)-based alternating optimization algorithm is proposed, where an optimization problem containing only constant modulus constraints in Euclidean space can be converted to an unconstrained optimization problem in a Riemann manifold. Furthermore, considering more practical cases with estimation errors of CSI, we investigate the robust joint HBF design with the system operating in full-duplex (FD) mode to obtain higher spectral efficiency (SE). A null-space projection (NP) based self-interference cancellation (SIC) algorithm is developed to attenuate the self-interference (SI). Different from the traditional SI suppression algorithm, there’s no limit on the number of RF chains. Numerical results reveal that our proposed algorithms has a good convergence and can effectively deal with the influence of different CSI estimation errors. A significant performance improvement can be achieved in contrast with other approaches.

A robustness-oriented procedure for the design of tying reinforcement in precast concrete hollow-core floors

Buildings may be subjected during their service life to extreme events which can trigger progressive collapse. On this front, the role played by tying reinforcement in structural members is crucial for an adequate load redistribution and the avoidance of disproportionate collapse. This work proposes a robustness-oriented procedure for the design of tying reinforcement placed in the hollow-core units and beams of precast concrete buildings, where limited studies are available in scientific literature. In particular, the aim is to provide a simple yet reliable approach for the design of concentrated and distributed ties in precast floors by adopting fundamental input parameters such as the system’s chord rotation capacity and dynamic amplification factor, which are not considered in current design codes. Firstly, a flow-chart of the design procedure is proposed and discussed. Secondly, the input parameters are calculated based on recent analytical approaches - proposed by some of the authors - to optimize the tying reinforcement design. Finally, the efficiency of the design procedure is demonstrated with an application example, and a novel detailing scheme is proposed which is aimed at a significant enhancement of structural robustness. Due to its simplicity, the proposed design procedure is contended to be applicable in robustness assessment and design of building structures with precast concrete hollow-core floors.