{"title":"Reinforcement Learning Generalization for Quadrotor With Slung Load Systems Through Homogeneity Transformations","authors":"Abdel Gafoor Haddad;Igor Boiko;Yahya Zweiri","doi":"10.1109/OJIES.2025.3557206","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3557206","url":null,"abstract":"Load transportation through unmanned aerial vehicles (UAVs), such as quadrotors, has a high potential for quick deliveries to locations that are out of the reach of ground vehicles. The complexity of the pick-and-place procedure in such tasks increases if the target location does not have a clearance at the top, necessitating the use of recent learning-based controllers such as reinforcement learning (RL). This article presents a new concept of dual-scale homogeneity, a property defined by scaled magnitudes and time in transformed coordinates that remain independent of system parameters. It demonstrates that applying transformations to achieve this property ensures consistent performance of a quadrotor with a slung load system (QSLS) despite variations in its parameters. Furthermore, it also presents an effective approach to design a parameter-dependent RL policy that homogenizes the QSLS. Unlike plain RL or gain-scheduled proportional-integral-derivative controllers, which confine parameter variations within a predefined range encountered during training or tuning, the developed approach works under large parameter variations, significantly surpassing the performance of traditional controllers. The conducted experiments on load placement in a confined space, utilizing a quadrotor to manage load swing, proved the proposed synergy between the homogeneity transformations and RL, yielding a success rate of 96% in bringing the load to its designated target with a 3-D RMSE of 0.0253 m.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"560-574"},"PeriodicalIF":5.2,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10947528","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Misalignment-Tolerant AUV-Capable Magnetic Coupler for Underwater Wireless Charging Systems","authors":"Chi-Fong Ieong;Hou-Wa Wong;Io-Wa Iam;Chi-Seng Lam","doi":"10.1109/OJIES.2025.3556244","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3556244","url":null,"abstract":"In the underwater environment, autonomous underwater vehicles (AUVs) have seen substantial use in the submarine environment. To avoid surfacing the AUV for recharging, magnetic coupler (MC)-embedded docking stations and AUVs for underwater wireless charging have attracted much attention in recent years. In this article, we propose a misalignment-tolerant, light-weighted, AUV-capable MC structure for underwater wireless charging applications. With the proposed design, the MC can provide a relatively stable coupling even under various types of coil misalignment. We also provide an analytical method to estimate the mutual inductance of the proposed MC under different positions. Simulations on the MC design are performed by using ANSYS Maxwell to evaluate its performance under different misalignment scenarios. To verify the viability of the proposed MC in an inductive power transfer system, a 750-W wireless charging experimental prototype was built in the laboratory with the proposed MC design. With a light-weighted and compact receiver of 320 g and 110 cm<sup>3</sup>, the system can achieve a maximum efficiency of 93.1%. Even under different coils’ axial, rotational, and off-center misalignment scenarios, the measured system efficiency is over 92%.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"548-559"},"PeriodicalIF":5.2,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10945652","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abdullah Berkay Bayindir;Ali Sharida;Sertac Bayhan;Haitham Abu-Rub
{"title":"Enhanced Inverse Model Predictive Control for EV Chargers: Solution for DC–DC Side","authors":"Abdullah Berkay Bayindir;Ali Sharida;Sertac Bayhan;Haitham Abu-Rub","doi":"10.1109/OJIES.2025.3553061","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3553061","url":null,"abstract":"This article presents an approach for enhancing the reliability and robustness of electric vehicle (EV) chargers, particularly the dc–dc side of the EV chargers, by using the inverse model predictive control (IMPC). IMPC, a recently introduced control method for power electronic converters, leverages the strengths of model predictive control (MPC), while minimizing its computational burden. IMPC excels in managing sophisticated and nonlinear systems, controlling multiple objectives, and adhering to various constraints. However, the effectiveness of conventional IMPC is heavily dependent on the accurate dynamic model of the power converter. This dependency makes IMPC susceptible to uncertainties and disturbances. To address this challenge, the proposed method employs an adaptive estimation strategy utilizing a recursive least square algorithm for online dynamic model estimation. This real-time estimated model enables IMPC to predict optimal switching states with improved reliability. The proposed control technique is designed to provide constant power, constant current, and constant voltage modes, with the ability to seamlessly transition between them. The efficacy of this technique is demonstrated through extensive simulations and experimental validation for a dual active bridge (DAB) converter. This adaptive method underscores the potential of IMPC for practical EV charging scenarios, ensuring reliable and high-performance charging.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"478-490"},"PeriodicalIF":5.2,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10935818","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Minimizing Interference in Robotic Rehabilitation via Asymmetric Stiffness Force Fields","authors":"Yasuhiro Kato;Sho Sakaino;Toshiaki Tsuji","doi":"10.1109/OJIES.2025.3570789","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3570789","url":null,"abstract":"This article introduces a novel approach for guiding human arm movement in the context of robotic rehabilitation. We propose upper limb movement guidance using a force field based on an asymmetric stiffness matrix. By introducing asymmetry in stiffness design, the proposed force field can deflect arm movement toward the target direction of a reaching movement while minimizing impeding effects. We hypothesize that this method can guide a human in the desired direction without interfering with their voluntary movement. To evaluate the performance of the human arm guidance technique, we conducted upper limb reaching experiments using a 2-degree-of-freedom robot arm with ten healthy volunteers. The experimental results revealed that the proposed approach demonstrated a similar reduction in movement error compared to the conventional stiffness approach. Moreover, participants exhibited higher movement activeness, and robotic interference with human movement was lower. The proposed approach may improve movement guidance based on stiffness control by enabling the robot to guide without inhibiting voluntary movement.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"840-850"},"PeriodicalIF":5.2,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11006019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seong Jin Lim;Sung-Geun Song;Guangxu Zhou;Feel-Soon Kang
{"title":"Comparison of Surge Voltage Reduction and Economic Efficiency of DC SSCBs According to MOV and RCD Snubber Combination","authors":"Seong Jin Lim;Sung-Geun Song;Guangxu Zhou;Feel-Soon Kang","doi":"10.1109/OJIES.2025.3551369","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3551369","url":null,"abstract":"Metal oxide varistor (MOV) is a nonlinear resistive element whose resistance decreases rapidly when the applied voltage exceeds a threshold value. A dc solid-state circuit breaker (SSCB) uses MOVs or MOV with resistor-capacitor-diode (RCD) snubber circuit combinations to reduce the surge voltage that occurs when breaking a fault current. The more MOV and RCD circuit components are added, the greater the surge voltage reduction effect. However, an increase in several parts leads to a rise in the cost of the snubber circuit. This article aims to find an economical circuit structure that improves the surge voltage reduction rate and does not increase the cost significantly by adding MOV and RCD snubber combinations to the conventional MOV-based surge voltage reduction circuits. First, three circuit combinations employing MOV, R, C, and diodes are presented. We confirm the proposed snubber circuit structures effectively reduce surge voltage by comparing surge voltage reduction rates through theoretical analysis, simulation, and experiment. Second, cost model analysis for the proposed circuits is used to calculate the total price of components. Finally, the economic feasibility of the proposed snubber circuits is evaluated by the cost required to achieve a 1% surge voltage reduction rate. The results of this article facilitate the selection of an economical circuit structure that combines additional MOV or RCD snubbers in the conventional MOV-based snubber circuits to reduce the surge voltage of SSCBs while minimizing cost increase.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"522-534"},"PeriodicalIF":5.2,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10925887","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An Overview of Inertia Emulation Strategies for DC Microgrids: Stability Analysis and AC Microgrid Analogies","authors":"Mahdis Haddadi;Saman A. Gorji;Samson S. Yu","doi":"10.1109/OJIES.2025.3550625","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3550625","url":null,"abstract":"Inertia is a critical factor in maintaining the frequency stability of power systems. However, the growing integration of power electronics-based renewable energy sources (RESs) has significantly reduced system inertia. AC and dc microgrids have emerged as key solutions for integrating RESs. Unlike traditional synchronous generators, power electronic converters interfacing RESs lack inherent inertia and damping, posing challenges to the control and stability of these microgrids. To address these challenges, virtual inertia control strategies, which emulate the behavior of synchronous generators, have been widely adopted to enhance the stability of ac microgrids. Drawing on the analogies between ac and dc systems, similar virtual inertia concepts have been extended to dc microgrids, demonstrating their potential to improve system stability. This article provides a comprehensive review of inertia enhancement strategies for dc microgrids, examining their key features, benefits, and limitations. The analogy between synchronous generators/dc machines and energy storage systems is explored, with a particular focus on the implementation of virtual inertia and damping control in energy storage converters as a promising solution to mitigate power fluctuations. In addition, this article investigates the grid-forming and grid-following converter analogies in ac and dc microgrids. Various stability analysis methods applied to inertia enhancement strategies are also reviewed, offering readers a comprehensive understanding of the current state of research. By addressing the conceptual and technical analogies between ac and dc systems, this review aims to provide valuable insights for developing advanced control strategies for next-generation microgrids.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"491-521"},"PeriodicalIF":5.2,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10923700","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Improved Direct Power Control of T-Type Rectifiers With Parameter Robustness Feedforward Compensation for DC-Bus Voltage Ripple Suppression Under Unbalanced Grid Conditions","authors":"Yi-Hung Liao;Jia-Sheng Liu;Pu-Yi Huang;Ping-Ju Chen","doi":"10.1109/OJIES.2025.3549475","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3549475","url":null,"abstract":"In a three-phase three-level ac/dc converter, the T-type rectifier features high efficiency and lower power switch stress, and it allows the dc-side voltage to serve as two independent output voltage sources. In practical applications, the operation of the T-type rectifier under unbalanced three-phase grid conditions must be considered. This article establishes an improved direct power control structure based on extended power theory under unbalanced grid conditions to achieve distortion-free current for the T-type rectifier. Additionally, a feedforward virtual capacitor power compensation is created to eliminate the output voltage ripples caused by the ripple power of the rectifier inductance under the unbalanced three-phase grid. The controller design of the improved direct power control and the choice of the virtual capacitor are analyzed. Furthermore, the proposed method regulates the neutral point voltage of the T-type rectifier, eliminates neutral point current disturbances, and provides a stable and accurate dc output voltage, ensuring high quality power supply. The proposed strategy does not require a phase-locked loop or ac-side system parameters, resulting in excellent dynamic performance and robustness against parameter mismatches. Finally, the effectiveness and feasibility of the proposed control strategy are verified through simulation results and the implementation of a 2.4 kW three-phase T-type rectifier.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"429-444"},"PeriodicalIF":5.2,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10918756","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"New Bidirectional Isolated Three-Phase DC–DC Converter With Parallel-to-Serial Configuration for Energy Applications","authors":"Jorge Jiménez-Giménez;Antonio Lázaro;Álvar Mayor;Jaime López-López;Andrés Barrado","doi":"10.1109/OJIES.2025.3548842","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3548842","url":null,"abstract":"This article presents a set of bidirectional dc–dc power converter solutions for high-voltage, high-power applications using magnetic and semiconductor devices that need to handle a small fraction of the rated power and voltage. The elements are integrated in an interleaved operation, which results in the generation of a low rms and pseudosine phase current. All these features result in a topology with a high level of efficiency, maintaining soft-switching over the entire operating range. Steady-state equations and simulation results are presented and then experimentally validated with a 25 kW prototype converter. Finally, it is verified that the solution is suitable for the needs of the proposed dc-microgrid scenario, that includes hydrogen production and an EV-charger, using solar PV-panels and battery energy storage systems as energy sources.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"459-477"},"PeriodicalIF":5.2,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10916738","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roberto Martín López;Sergio de López Diz;Alessandro Faro;Emilio José Bueno Peña;Alessandro Lidozzi
{"title":"Grid-Forming Controller for Multi DC/AC Converter Topology Supplying 25 kVAC Single-Phase Railway Catenary From 3 kVDC","authors":"Roberto Martín López;Sergio de López Diz;Alessandro Faro;Emilio José Bueno Peña;Alessandro Lidozzi","doi":"10.1109/OJIES.2025.3548456","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3548456","url":null,"abstract":"One of the primary challenges associated with single-phase AC railway electrification is the unbalance created within the three-phase supply grid. This problem does not arise in DC electrification systems. The aim of this article is to introduce a novel Grid-Forming control strategy, which applied to a power electronics based topology allows the generation of an AC catenary from the DC catenary. Focusing on the capabilities of the control algorithm, the system is presented as a fully scalable solution employing multiple grid-forming DC/AC converters. These converters use power control loops based on the Virtual Synchronous Machine concept, adapted to single-phase operation. A key advantage of this approach is that all converters within the system contribute to supporting both voltage and frequency stability. In addition, the implementation does not require a higher-level controller or communication system. Through an appropriate power control design, the power supplied by each converter, relative to the total load demand, can be determined.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"445-458"},"PeriodicalIF":5.2,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10914004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Otto—Design and Control of an 8-DoF SEA-Driven Quadrupedal Robot","authors":"Antonello Scaldaferri;Simone Tolomei;Francesco Iotti;Paolo Gambino;Michele Pierallini;Franco Angelini;Manolo Garabini","doi":"10.1109/OJIES.2025.3567112","DOIUrl":"https://doi.org/10.1109/OJIES.2025.3567112","url":null,"abstract":"This article presents the mechanical design of Otto, a lightweight 8-degrees-of-freedom (8-DoF) quadrupedal robot employing series elastic actuators, and a training framework for learning locomotion control policies in simulation using reinforcement learning (RL). Otto's design differs from typical 12-DoF quadrupeds by lacking hip adduction–abduction DoF. This reduces the robot's cost and weight and increases complexity for tasks involving base rotation and angular twist following. The elastic elements at the joints improve compliance, energy efficiency, safety, and stability, increase robustness, and reduce damage to robot hardware components. Our locomotion control approach leverages RL to optimize policies in simulation, allowing stable and efficient movement despite mechanical constraints, i.e., an 8-DoF quadrupedal robot. Through extensive simulation training, leveraging highly parallel Graphics Processing Unit (GPU)-accelerated robotic simulators, we ensure the policy is well-suited for deployment in real-world scenarios, where accurate motion control is critical for performance. The trained policy is then transferred to the physical robot platform. We demonstrate its effectiveness in various tasks and real-life scenarios with varying payloads and terrains, and compare it with a state-of-the-art model-based method. The results show that Otto, equipped with our RL-based locomotion control, achieves robust performance, compensating for the reality gap and managing the reduced DoF available in Otto.","PeriodicalId":52675,"journal":{"name":"IEEE Open Journal of the Industrial Electronics Society","volume":"6 ","pages":"820-839"},"PeriodicalIF":5.2,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10988638","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144177410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}