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This study develops a new class of Euler-buckled beam based nonlinear energy sink (EBNES) with three configurations, which is expected to attenuate the disturbance effects and further enhance vibration suppression under launching and on-orbit loads simultaneously. The effects of different arrangements on amplitude-frequency responses of the primary system are derived and analyzed through complexification-averaging method, and the approximate solutions are verified by fourth-order Runge Kutta method. Comparison results exhibit that the EBNES-I is much more effective with enhanced vibration reduction performance and stability in a broad frequency range. Furthermore, a two-degree-of-freedom dynamic model of the flywheel system, which integrates the EBNES-I and the supporting structure in satellite, is established. The vibration reduction and bifurcation behaviors of the proposed EBNES-I are investigated, and the efficiency of the proposed EBNES-I in vibration reduction of the flywheel is compared to that of a traditional cubic-stiffness-type NES. It is found that the EBNES-I exhibits a good vibration reduction performance on the dynamic responses of the flywheel system in launching and on-orbit stage simultaneously. Additionally, the bifurcations of the coupled system are studied in order to investigate the influences of gravity and excitation amplitudes on the stability of the EBNES. Calculation results provide conditions for occurrence of the saddle-node (SN) and Hopf bifurcations. [ABSTRACT FROM AUTHOR]

We evaluated the effects of post-activation performance enhancement through flywheel exercise with varying inertial loads compared to traditional resistance exercise on countermovement jump performance and muscle recruitment. In a randomized crossover design, 13 trained men completed four main experimental trials after three familiarization sessions. These conditions included a traditional trial consisting of 5 sets of 1 repetition using the Smith machine (SM) squat at 90% 1RM, and three flywheel ergometer trials. Each flywheel protocol consisted of 3 sets of 8 repetitions with 3-minute rest intervals between sets, utilizing one of three inertial loads (0.0465, 0.0784, and 0.1568 kg · m2 for light, moderate, and heavy, respectively). Participants performed countermovement jumps before (baseline), immediately after (0 minute), and at the fourth (+4 minutes), eighth (+8 minutes), and twelfth (+12 minutes) minute following exercise. Compared to baseline, jump height was higher at +4 minutes for SM squats (p = 0.009). All flywheel conditions exhibited higher jump heights at +4 minutes (p < 0.05), +8 minutes (p < 0.001), and +12 minutes (p < 0.001) compared to baseline. Additionally, moderate and heavy loads resulted in higher jump heights at 0 minute (both p < 0.001). Integrated electromyographic activity values, a proxy for muscle recruitment, were significantly higher for the gluteus maximus muscle at both +8 minutes and +12 minutes for moderate (both p = 0.004) and heavy loads (p ≤ 0.002) compared to SM squats. Overall, flywheel protocols produce greater post-activation performance enhancement, extend the time window for improvement, and recruit more active musculature compared to heavy-load SM squats, particularly with heavier loads acting as a stronger preload stimulus. [ABSTRACT FROM AUTHOR]

Compared to traditional, static-based flywheel systems, vehicle-mounted magnetic suspension flywheels face more complex operating conditions, and existing control strategies usually regard disturbances in vehicles under different operating conditions to be the same problem. Therefore, it is necessary to determine the interference from complex operating conditions and reasonably distinguish among them under different operating conditions to provide flywheel systems with strong stability (the rotor offset was less than 0.025 mm). Thus, this paper proposes a high-stability control strategy for flywheels based on the classification of vehicle-driving conditions and designs its control strategy by taking the vehicle-mounted magnetic suspension flywheel with a virtual inertia spindle as an example. First, according to the different vehicle working conditions and the varying interference intensities affecting the flywheel system, the working mode is divided into four modes. Considering the obvious differences in each working mode, it is proposed to use BP neural network optimization based on the simulated annealing algorithm (SA-BPNN) to determine the flywheel's working condition. A relatively simple neural network can improve the response speed of the whole system. It also has a good effect. Secondly, it is proposed to use deep learning models based on convolutional neural networks, long short-term memory networks and attention mechanisms (CNN+LSTM+ATTENTION) to train the corresponding control parameters under each working condition to judge and predict the control parameters under different working conditions. Three evaluation parameters are used to evaluate the training results, and all achieved good results. Finally, the classification of working conditions and performance tests are carried out. The experimental results show the effectiveness and superiority of the proposed control strategy. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate and compare the effects of inertial flywheel training and accentuated eccentric loading training on the neuromuscular performance of well-trained male college sprinters. Fourteen sprinters were recruited and randomly assigned to either the flywheel training (FWT, n = 7) group or the accentuated eccentric loading training (AELT, n = 7) group. The FWT group completed four sets of 2 + 7 repetitions of flywheel squats, whereas the AELT group performed four sets of seven repetitions of barbell squats (concentric/eccentric: 80%/120% 1RM). Both groups underwent an eight-week squat training program, with two sessions per week. A two-way repeated ANOVA analysis was used to find differences between the two groups and between the two testing times (pre-test vs. post-test). The results indicated significant improvements in all measured variables for the FWT group: 1RM (5.0%, ES = 1.28), CMJ (13.3%, ES = 5.42), SJ (6.0%, ES = 2.94), EUR (6.5%, ES = 4.42), SLJ (2.9%, ES = 1.77), and 30 m sprint (−3.4%, ES = −2.80); and for the AELT group: 1RM (6.3%, ES = 2.53), CMJ (7.4%, ES = 3.44), SJ (6.4%, ES = 2.21), SLJ (2.2%, ES = 1.20), and 30 m sprint (−3.0%, ES = −1.84), with the exception of EUR (0.9%, ES = 0.63, p = 0.134), showing no significant difference. In addition, no significant interaction effects between group and time were observed for 1RM back squat, SJ, SLJ, and 30 m sprint (p > 0.05). Conversely, a significant interaction effect between group and time was observed for both CMJ and EUR (p < 0.001); post hoc analysis revealed that the improvements in CMJ and EUR were significantly greater in the FWT group compared to the AELT group (p < 0.001). These findings indicate that both FWT and AELT are effective at enhancing lower-body strength, power, and speed in well-trained male college sprinters, with FWT being particularly more effective in promoting elastic energy storage and the full utilization of the stretch–shortening cycle. [ABSTRACT FROM AUTHOR]

In order to solve the problem of frequency modulation power deviation caused by the randomness and fluctuation of wind power outputs, a method of auxiliary wind power frequency modulation capacity allocation based on the data decomposition of a "flywheel + lithium battery" hybrid-energy storage system was proposed. Firstly, the frequency modulation power deviation caused by the uncertainty of wind power is decomposed by the successive variational mode decomposition (SVMD) method, and the mode function is segmented and reconstructed by high and low frequencies. Secondly, a mathematical model is established to maximize the economic benefit of energy storage considering the frequency modulation mileage, and quantum particle swarm optimization is used to solve the target model considering the charging and discharging power of energy storage and the charging state constraints to obtain the optimal hybrid-energy storage configuration. Finally, the simulation results show that, in the step disturbance, the Δfmax of the hybrid-energy storage mode is reduced by 37.9% and 15.3%, respectively, compared with single-energy storage. Under continuous disturbance conditions, compared with the single-energy storage mode, the Δfp_v is reduced by 52.73%, 43.72%, 60.71%, and 47.62%, respectively. The frequency fluctuation range is obviously reduced, and the frequency stability is greatly improved. [ABSTRACT FROM AUTHOR]

The most common and destructive event of unsteady flow in pipes is water hammer. This phenomenon is caused by a sudden change in boundary conditions in pressurized pipes. Unsteady flow in pipelines can lead to a significant increase or decrease in pressure. This pressure generation may cause cavitation, bursting of pipes, and failure of the whole system. One type of equipment that can control both positive and negative pressure phases is a pressurized tank. Implementing such a pressure tank can impose increased costs. In order to reduce the design costs, the combination of a flywheel with the pressure tank can be used. In this study, a transmission pipeline from Zarineh River to Tabriz city is numerically simulated, and the effect of increasing the inertia of the flywheel on the reduction of the pressurized tank volume is investigated. The results show that increasing the flywheel inertia from 125 to 165 Nm2 can reduce the pressurized tank volume from 90 to 75 m3. [ABSTRACT FROM AUTHOR]

To solve the problem that the poor accuracy of long-term prediction relying on model accuracy for the filter-based prediction method, a fusion fault prediction algorithm based on filter and long short-term memory (LSTM) network is proposed to achieve the prediction of spacecraft flywheel slowly growing faults. Firstly, a mini-batch normalization LSTM network and a trend recognition module are designed, which are connected in series to form a neural network predictor to improve the time series prediction accuracy. Then, the Kalman filter update process is improved by the recursive least square (RLS) parameter estimation principle to enhance the robustness for time series prediction error. On this basis, the predicted values output by the neural network predictor are fused with the improved filter. Prediction residual can be obtained for iterative updating and prediction, overcoming the dependence of the filter algorithm on the model and improving prediction accuracy. Finally, the time series predictive performance of three neural network predictors are analyzed by simulation experiments. And considering the degradation fault of flywheel bearing performance, the proposed fusion prediction algorithm is used to determine that the flywheel degrades to a threshold at 856 s, with a prediction time error of 36 s. The simulation results verify the effectiveness of the proposed algorithm for slowly growing fault.

A multiyear power system R&D program was completed with the objective of developing an off-road hybrid heavy duty diesel engine with front end accessory drive-integrated energy storage. This system was validated to deliver 10.5-25.6% reduction in fuel consumption over current Tier 4 Final-based 18L diesel engines, over various off-road machine application cycles. The power system consisted of a downsized heavy-duty diesel 13L engine containing advanced combustion technologies, capable of elevated peak cylinder pressures and thermal efficiencies, thermal barrier coatings, exhaust waste heat recovery via SuperTurbo™ turbocompounding, and hybrid energy assisting and recovery through both mechanical and electrical systems. Following the concept definition, design, and analysis phases of the program, the final phase focused on building and validating the performance and efficiency in laboratory tests. While aspects of the system such as start/stop and reduced off-road cooling package energy losses were only analytically evaluated, the main 13L concept engine with full hybrid system was successfully built and tested in steady-state and in transient certification and real-world application cycles. Extensive simulations in Caterpillar's DYNASTY™ software environment utilized the validation test data to assess performance more fully and confidently over varied cycles and strategies. An average fuel consumption reduction of 17.9% was realized, and the majority (~13%) of the benefit stemmed from the core concept 13L engine. To conclude, a total cost of ownership analysis provides context to commercial viability and where adoption focus should be placed. [ABSTRACT FROM AUTHOR]

Monitoring the strain in the rotating flywheel in a kinetic energy storage system is important for safe operation and for the investigation of long-term effects in composite materials like carbon-fiber-reinforced plastics. An optoelectronic strain-measurement system for contactless deformation and position monitoring of a flywheel was investigated. The system consists of multiple optical sensors measuring the local relative in-plane displacement of the flywheel rotor. A special reflective pattern, which is necessary to interact with the sensors, was applied to the surface of the rotor. Combining the measurements from multiple sensors makes it possible to distinguish between the deformation and in-plane displacement of the flywheel. The sensor system was evaluated using a low-speed steel rotor for single-sensor performance investigation as well as a scaled-down high-speed rotor made from PVC plastic. The PVC rotor exhibits more deformation due to centrifugal stresses than a steel or aluminum rotor of the same dimensions, which allows experimental measurements at a smaller flywheel scale as well as a lower rotation speed. Deformation measurements were compared to expected deformation from calculations. The influence of sensor distance was investigated. Deformation and position measurements as well as derived imbalance measurements were demonstrated. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To address our climate emergency, "we must rapidly, radically reshape society"—Johnson & Wilkinson, All We Can Save. In science, reshaping requires formidable technical (cloud, coding, reproducibility) and cultural shifts (mindsets, hybrid collaboration, inclusion). We are a group of cross‐government and academic scientists that are exploring better ways of working and not being too entrenched in our bureaucracies to do better science, support colleagues, and change the culture at our organizations. We share much‐needed success stories and action for what we can all do to reshape science as part of the Open Science movement and 2023 Year of Open Science. [ABSTRACT FROM AUTHOR]

An investigation on a flywheel is presented based on finite element modelling simulations for different geometries. The goal was to optimise the energy density (rotational energy-to-mass ratio) and, at the same time, the rotational energy of a flywheel rotor. The stress behaviour of flywheel rotors under the rotational speed at the maximum stress achievable by the flywheel was analysed. Under this condition, the energy density was obtained for the different geometries, as well as the rotational energy. The best energy density performance due to geometry was achieved with a flywheel rotor presenting a new Gaussian section, which is different from the known Laval disk shape. The best results using a single disk involved a rotational speed of nearly 279,000 rpm and a rotational energy density around 1584 kJ/kg (440 Wh/kg). These values still yielded low total energy; to increase its value, two or three rotors were added to the flywheel, which were analysed in regard to stability. In particular, the triple rotor energy density was ≈ 1550 kJ/kg (431 Wh/kg). As some instability was found in these rotors, a solution using reinforcement was developed to avoid such instabilities. The energy density of such a reinforced double rotor neared 1451 kJ/kg (403 Wh/kg), and the system achieved higher total energy. The material assumed for the devices was carbon fibre Hexcel UHM 12,000, a material kept constant throughout the simulations to allow comparison among the different geometries. [ABSTRACT FROM AUTHOR]

With the continuous improvement of the performance and capabilities of spacecrafts, the application of active magnetic bearings (AMBs) has become a major focus in current research. The AMBs-flywheel system is not only responsible for attitude control but also provides the required energy during shadow periods. In magnetically suspended single gimbal control moment gyroscope (SGCMG), self-excited vibration caused by high-speed rotor rotation significantly affects the stability of the AMB system. The research focus lies in magnetically supporting the flywheel at high speeds with low power consumption to explore gyroscopic mechanics at ultra-high speeds and assess the corresponding stability. This study presents an assessment of the stability performance of a high-speed flywheel equipped on a single gimbal with an angular momentum of 75 Nm. To achieve ultra-high-speed operation under low driving power, a high-precise dynamic balance was performed followed by a novel unbalance control strategy of a radial and axial automatic balancing algorithm to suppress effectively synchronous vibrations due to nutation and precession. Corresponding experiments including static stable suspension experiments as well as low-speed, high-speed, and series-based stability assessments were conducted. Stable suspension at any speed ranging from 0 to 30,000 r/min was successfully implemented. The stability performance of the high-speed flywheel on a rotating platform at different gimbal speeds was verified, with a maximum speed reaching 31,200 r/min. The entire output torque process within the range of 30,000 r/min was revealed. [ABSTRACT FROM AUTHOR]

Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The flywheel is a widespread mechanical component used for the storage of kinetic energy and angular momentum. It typically consists of cylindrical inertia rotating about its axis on rolling bearings, which involves undesired friction, lubrication, and wear. This paper presents an alternative mechanism that is functionally equivalent to a classical flywheel while relying exclusively on limited-stroke flexure joints. This novel one-degree-of-freedom zero-force mechanism has no wear and requires no lubrication: it is thus compatible with extreme environments, such as vacuum, cryogenics, or ionizing radiation. The mechanism is composed of two coupled pivoting rigid bodies whose individual angular momenta vary during motion but whose sum is constant at all times when the pivoting rate is constant. The quantitative comparison of the flexure-based flywheel to classical ones based on a hollow cylinder as inertia shows that the former typically stores 6 times less angular momentum and kinetic energy for the same mass while typically occupying 10 times more volume. The freedom of design of the shape of the rigid bodies offers the possibility of modifying the ratio of the stored kinetic energy versus angular momentum, which is not possible with classical flywheels. For example, a flexure-based flywheel with rigid pivoting bodies in the shape of thin discs stores 100 times more kinetic energy than a classical flywheel with the same angular momentum. A proof-of-concept prototype was successfully built and characterized in terms of reaction moment generation, which validates the presented analytical model. [ABSTRACT FROM AUTHOR]

Energy storage systems are essential in modern energy infrastructure, addressing efficiency, power quality, and reliability challenges in DC/AC power systems. Recognized for their indispensable role in ensuring grid stability and seamless integration with renewable energy sources. These storage systems prove crucial for aircraft, shipboard systems, and electric vehicles, addressing peak load demands economically while enhancing overall system reliability and efficiency. Recent advancements and research have focused on high-power storage technologies, including supercapacitors, superconducting magnetic energy storage, and flywheels, characterized by high-power density and rapid response, ideally suited for applications requiring rapid charging and discharging. Hybrid energy storage systems and multiple energy storage devices represent enhanced flexibility and resilience, making them increasingly attractive for diverse applications, including critical loads. This paper provides a comprehensive overview of recent technological advancements in high-power storage devices, including lithium-ion batteries, recognized for their high energy density. In addition, a summary of hybrid energy storage system applications in microgrids and scenarios involving critical and pulse loads is provided. The research further discusses power, energy, cost, life, and performance technologies. [ABSTRACT FROM AUTHOR]

This paper presents the development of an airport bipolar DC microgrid and its interconnected operations with the utility grid, electric vehicle (EV), and more electric aircraft (MEA). The microgrid DC-bus voltage is established by the main sources, photovoltaic (PV) and fuel cell (FC), via unidirectional three-level (3L) boost converters. The proposed one-cycle control (OCC)-based current control scheme and quantitative and robust voltage control scheme are proposed to yield satisfactory responses. Moreover, the PV maximum power point tracking (MPPT) with FC energy-supporting approach is developed to have improved renewable energy extraction characteristics. The equipped hybrid energy storage system (HESS) consists of an energy-type battery and a power-type flywheel; each device is interfaced to the common DC bus via its own 3L bidirectional interface converter. The energy-coordinated operation is achieved by the proposed droop control. A dump load leg is added to avoid overvoltage due to an energy surplus. The grid-connected energy complementary operation is conducted using a neutral point clamped (NPC) 3L three-phase inverter. In addition to the energy support from grid-to-microgrid (G2M), the reverse mcrogrid-to-grid (M2G) operation is also conductible. Moreover, microgrid-to-vehicle (M2V) and vehicle-to-microgrid (V2M) bidirectional operations can also be applicable. The droop control is also applied to perform these interconnected operations. For the grounded aircraft, bidirectional microgrid-to-aircraft (M2A)/aircraft-to-microgrid (A2M) operations can be performed. The aircraft ground power unit (GPU) function can be preserved by the developed microgrid. The MEA on-board facilities can be powered by the microgrid, including the 115 V/400 Hz AC bus, the 270 V DC bus, the switched-reluctance motor (SRM) drive, etc. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The primary aim of this study was to investigate the intra- and inter-day reliability of flywheel cluster set training in concentric power (CON), eccentric power (ECC), and ECC overload during the Romanian deadlift exercise (RDL). A secondary aim was to assess the acute effect of internal and external attentional focus instructions on mean power when performing the flywheel RDL. Fourteen collegiate male field sport athletes (age, 23.3 ± 3.7 years; mass, 80.8 ± 9.9 kg; height, 1.79 ± 0.06 m) were randomized into internal (n = 7) or external (n = 7) attentional focus groups and attended four testing sessions, with a between-session separation of 7 days. Sessions consisted of four cluster sets of fifteen repetitions "excluding momentum repetitions" (4 × (5 + 5 + 5)) using a specific inertial load (0.025, 0.050, 0.075, and 0.100 kg·m−2) for a given set in a randomized ascending or descending order. Cluster sets were separated by a 45 s intra-set rest period. Both instructional focus groups attained familiarization, although the time taken to achieve familiarization (outcome stability) differed between groups. The external instructional group attained familiarization post-session 2 (Cohen's d (ES), ES = 0.11–0.65) with little volatility between performance measures (CV% = 4.61–9.59). Additionally, the internal group reported inconsistencies among all inertial loads, reporting large differences in MP in the 0.100 kg·m−2 inertial load from day 2 to day 3 (ES = 1.22) and both 0.050 kg·m2 (p = 0.010) and 0.075 kg·m−2 (p = 0.016) between day 3 and day 4. The flywheel RDL cluster set approach is a reliable training modality for maintaining mean power output during cluster set repetitions. [ABSTRACT FROM AUTHOR]

Abstract To address our climate emergency, “we must rapidly, radically reshape society”—Johnson & Wilkinson, All We Can Save. In science, reshaping requires formidable technical (cloud, coding, reproducibility) and cultural shifts (mindsets, hybrid collaboration, inclusion). We are a group of cross‐government and academic scientists that are exploring better ways of working and not being too entrenched in our bureaucracies to do better science, support colleagues, and change the culture at our organizations. We share much‐needed success stories and action for what we can all do to reshape science as part of the Open Science movement and 2023 Year of Open Science.

Compared to traditional, static-based flywheel systems, vehicle-mounted magnetic suspension flywheels face more complex operating conditions, and existing control strategies usually regard disturbances in vehicles under different operating conditions to be the same problem. Therefore, it is necessary to determine the interference from complex operating conditions and reasonably distinguish among them under different operating conditions to provide flywheel systems with strong stability (the rotor offset was less than 0.025 mm). Thus, this paper proposes a high-stability control strategy for flywheels based on the classification of vehicle-driving conditions and designs its control strategy by taking the vehicle-mounted magnetic suspension flywheel with a virtual inertia spindle as an example. First, according to the different vehicle working conditions and the varying interference intensities affecting the flywheel system, the working mode is divided into four modes. Considering the obvious differences in each working mode, it is proposed to use BP neural network optimization based on the simulated annealing algorithm (SA-BPNN) to determine the flywheel’s working condition. A relatively simple neural network can improve the response speed of the whole system. It also has a good effect. Secondly, it is proposed to use deep learning models based on convolutional neural networks, long short-term memory networks and attention mechanisms (CNN+LSTM+ATTENTION) to train the corresponding control parameters under each working condition to judge and predict the control parameters under different working conditions. Three evaluation parameters are used to evaluate the training results, and all achieved good results. Finally, the classification of working conditions and performance tests are carried out. The experimental results show the effectiveness and superiority of the proposed control strategy.

In order to solve the problem of frequency modulation power deviation caused by the randomness and fluctuation of wind power outputs, a method of auxiliary wind power frequency modulation capacity allocation based on the data decomposition of a “flywheel + lithium battery” hybrid-energy storage system was proposed. Firstly, the frequency modulation power deviation caused by the uncertainty of wind power is decomposed by the successive variational mode decomposition (SVMD) method, and the mode function is segmented and reconstructed by high and low frequencies. Secondly, a mathematical model is established to maximize the economic benefit of energy storage considering the frequency modulation mileage, and quantum particle swarm optimization is used to solve the target model considering the charging and discharging power of energy storage and the charging state constraints to obtain the optimal hybrid-energy storage configuration. Finally, the simulation results show that, in the step disturbance, the Δfmax of the hybrid-energy storage mode is reduced by 37.9% and 15.3%, respectively, compared with single-energy storage. Under continuous disturbance conditions, compared with the single-energy storage mode, the Δfp_v is reduced by 52.73%, 43.72%, 60.71%, and 47.62%, respectively. The frequency fluctuation range is obviously reduced, and the frequency stability is greatly improved.

Most haptic actuators available on the market today can generate only a single modality of stimuli. This ultimately limits the capacity of a kinaesthetic haptic controller to deliver more expressive feedback, requiring a haptic controller to integrate multiple actuators to generate complex haptic stimuli, with a corresponding complexity of construction and control. To address this, we designed a haptic controller to deliver several modalities of kinaesthetic haptic feedback using a single actuator: a flywheel, the orientation of which is controlled by two gimbals capable of rotating over 360 degrees, in combination with a flywheel brake. This enables the controller to generate multiple haptic feedback modalities, such as torque feedback, impact simulation, low-frequency high-amplitude vibrations, inertial effects (the sensation of momentum), and complex haptic output effects such as the experience of vortex-like forces (whirl effects). By combining these diverse haptic effects, the controller enriches the haptic dimension of VR environments. This paper presents the device's design, implementation, and characterization, and proposes potential applications for future work. [ABSTRACT FROM AUTHOR]

We compared the cardiovascular adaptations to resistance training (RT) using either traditional isotonic or iso-inertial resistance exercise in a randomized controlled study. Thirty-one healthy young adults (means ± SD, age = 24 ± 3 yr) completed 10 wk of traditional isotonic RT (TRT; n = 7 female/5 male), iso-inertial flywheel RT (FWRT; n = 7 female/4 male), or a habitual activity control (Con; n = 5 female/3 male). Before and following the intervention period, blood pressure, blood pressure reactivity, flowmediated dilation (FMD), carotid-femoral pulse wave velocity (cfPWV), baroreflex sensitivity (BRS), and heart rate variability (RMSSD) were assessed. TRT and FWRT similarly improved isometric muscle strength. TRT significantly increased systolic blood pressure reactivity during isometric exercise compared with both FWRT (mean difference ± 95% CI, þ10.8 ± 8.8 mmHg) and Con (þ11.8 ± 9.1 mmHg). Cardiovagal BRS was significantly reduced in TRT versus FWRT (-6.82 ± 4.9 ms/mmHg; P = 0.006) but not between TRT versus Con (P = 0.12) or FWRT versus Con (P = 0.43). Resting heart rate (RHR) and RMSSD worsened in TRT compared with FWRT (RHR, þ8 ± 5.8 beats/min, P = 0.006; RMSSD, -22.3 ± 15.6 ms, P = 0.004). Changes in BRS and RMSSD were associated with changes in blood pressure reactivity in the RT groups (r = -0.51 to -0.52). There were no significant changes in FMD or cfPWV in any group (P = 0.13). In conclusion, 10 wk of TRT and FWRT resulted in similar improvements in strength, but TRT caused impairments in blood pressure reactivity compared with FWRT and Con and parasympathetic nervous system activity compared with FWRT. [ABSTRACT FROM AUTHOR]

The increasing number of constellation satellites requires re-thinking of the design and manufacturing process for reaction wheel rotors. Mass optimisation of reaction wheel rotors leads to cost reduction and performance increase. Those optimisations can be realised by taking ideas from nature. Therefore, design principles of diatoms were screened, abstracted and implemented in an algorithm-based design process. In this way, a bio-inspired rotor was created, which considers launch and in-operation loads, is capable of up to 7500 RPM and shows a compact design with a diameter of 282 mm . Regarding mechanical performance, an energy density of 4661 J kg - 1 and a mass moment of inertia ratio of 0.7584, which considers the component and an idealized design, could be achieved. Compared to a commercial rotor, this is equivalent to a similar inertia ratio and +85 % energy density, but +44 % mass due to manufacturing restrictions. Based on different boundary conditions, different first natural frequency for launch and operation conditions were obtained ( 658 Hz and 210 Hz ). The new design was cast from nano-reinforced aluminium alloy (AlSi10Mg + Al2O3) in 3D-printed sand moulds that were produced via binder-jetting process. Thus, a hybrid manufacturing process was used, by combining additive manufacturing and casting. Post-processing of the cast part via turning and milling was performed to compensate distortion and achieve the required surface quality. Preliminary vibration measurements were performed, showing a large need for balancing to achieve low vibration emissions. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate and compare the effects of inertial flywheel training and accentuated eccentric loading training on the neuromuscular performance of well-trained male college sprinters. Fourteen sprinters were recruited and randomly assigned to either the flywheel training (FWT, n = 7) group or the accentuated eccentric loading training (AELT, n = 7) group. The FWT group completed four sets of 2 + 7 repetitions of flywheel squats, whereas the AELT group performed four sets of seven repetitions of barbell squats (concentric/eccentric: 80%/120% 1RM). Both groups underwent an eight-week squat training program, with two sessions per week. A two-way repeated ANOVA analysis was used to find differences between the two groups and between the two testing times (pre-test vs. post-test). The results indicated significant improvements in all measured variables for the FWT group: 1RM (5.0%, ES = 1.28), CMJ (13.3%, ES = 5.42), SJ (6.0%, ES = 2.94), EUR (6.5%, ES = 4.42), SLJ (2.9%, ES = 1.77), and 30 m sprint (−3.4%, ES = −2.80); and for the AELT group: 1RM (6.3%, ES = 2.53), CMJ (7.4%, ES = 3.44), SJ (6.4%, ES = 2.21), SLJ (2.2%, ES = 1.20), and 30 m sprint (−3.0%, ES = −1.84), with the exception of EUR (0.9%, ES = 0.63, p = 0.134), showing no significant difference. In addition, no significant interaction effects between group and time were observed for 1RM back squat, SJ, SLJ, and 30 m sprint (p > 0.05). Conversely, a significant interaction effect between group and time was observed for both CMJ and EUR (p < 0.001); post hoc analysis revealed that the improvements in CMJ and EUR were significantly greater in the FWT group compared to the AELT group (p < 0.001). These findings indicate that both FWT and AELT are effective at enhancing lower-body strength, power, and speed in well-trained male college sprinters, with FWT being particularly more effective in promoting elastic energy storage and the full utilization of the stretch–shortening cycle.

Monitoring the strain in the rotating flywheel in a kinetic energy storage system is important for safe operation and for the investigation of long-term effects in composite materials like carbon-fiber-reinforced plastics. An optoelectronic strain-measurement system for contactless deformation and position monitoring of a flywheel was investigated. The system consists of multiple optical sensors measuring the local relative in-plane displacement of the flywheel rotor. A special reflective pattern, which is necessary to interact with the sensors, was applied to the surface of the rotor. Combining the measurements from multiple sensors makes it possible to distinguish between the deformation and in-plane displacement of the flywheel. The sensor system was evaluated using a low-speed steel rotor for single-sensor performance investigation as well as a scaled-down high-speed rotor made from PVC plastic. The PVC rotor exhibits more deformation due to centrifugal stresses than a steel or aluminum rotor of the same dimensions, which allows experimental measurements at a smaller flywheel scale as well as a lower rotation speed. Deformation measurements were compared to expected deformation from calculations. The influence of sensor distance was investigated. Deformation and position measurements as well as derived imbalance measurements were demonstrated.

An investigation on a flywheel is presented based on finite element modelling simulations for different geometries. The goal was to optimise the energy density (rotational energy-to-mass ratio) and, at the same time, the rotational energy of a flywheel rotor. The stress behaviour of flywheel rotors under the rotational speed at the maximum stress achievable by the flywheel was analysed. Under this condition, the energy density was obtained for the different geometries, as well as the rotational energy. The best energy density performance due to geometry was achieved with a flywheel rotor presenting a new Gaussian section, which is different from the known Laval disk shape. The best results using a single disk involved a rotational speed of nearly 279,000 rpm and a rotational energy density around 1584 kJ/kg (440 Wh/kg). These values still yielded low total energy; to increase its value, two or three rotors were added to the flywheel, which were analysed in regard to stability. In particular, the triple rotor energy density was ≈ 1550 kJ/kg (431 Wh/kg). As some instability was found in these rotors, a solution using reinforcement was developed to avoid such instabilities. The energy density of such a reinforced double rotor neared 1451 kJ/kg (403 Wh/kg), and the system achieved higher total energy. The material assumed for the devices was carbon fibre Hexcel UHM 12,000, a material kept constant throughout the simulations to allow comparison among the different geometries.

With the continuous improvement of the performance and capabilities of spacecrafts, the application of active magnetic bearings (AMBs) has become a major focus in current research. The AMBs-flywheel system is not only responsible for attitude control but also provides the required energy during shadow periods. In magnetically suspended single gimbal control moment gyroscope (SGCMG), self-excited vibration caused by high-speed rotor rotation significantly affects the stability of the AMB system. The research focus lies in magnetically supporting the flywheel at high speeds with low power consumption to explore gyroscopic mechanics at ultra-high speeds and assess the corresponding stability. This study presents an assessment of the stability performance of a high-speed flywheel equipped on a single gimbal with an angular momentum of 75 Nm. To achieve ultra-high-speed operation under low driving power, a high-precise dynamic balance was performed followed by a novel unbalance control strategy of a radial and axial automatic balancing algorithm to suppress effectively synchronous vibrations due to nutation and precession. Corresponding experiments including static stable suspension experiments as well as low-speed, high-speed, and series-based stability assessments were conducted. Stable suspension at any speed ranging from 0 to 30,000 r/min was successfully implemented. The stability performance of the high-speed flywheel on a rotating platform at different gimbal speeds was verified, with a maximum speed reaching 31,200 r/min. The entire output torque process within the range of 30,000 r/min was revealed.

Energy storage systems are essential in modern energy infrastructure, addressing efficiency, power quality, and reliability challenges in DC/AC power systems. Recognized for their indispensable role in ensuring grid stability and seamless integration with renewable energy sources. These storage systems prove crucial for aircraft, shipboard systems, and electric vehicles, addressing peak load demands economically while enhancing overall system reliability and efficiency. Recent advancements and research have focused on high-power storage technologies, including supercapacitors, superconducting magnetic energy storage, and flywheels, characterized by high-power density and rapid response, ideally suited for applications requiring rapid charging and discharging. Hybrid energy storage systems and multiple energy storage devices represent enhanced flexibility and resilience, making them increasingly attractive for diverse applications, including critical loads. This paper provides a comprehensive overview of recent technological advancements in high-power storage devices, including lithium-ion batteries, recognized for their high energy density. In addition, a summary of hybrid energy storage system applications in microgrids and scenarios involving critical and pulse loads is provided. The research further discusses power, energy, cost, life, and performance technologies.

The flywheel is a widespread mechanical component used for the storage of kinetic energy and angular momentum. It typically consists of cylindrical inertia rotating about its axis on rolling bearings, which involves undesired friction, lubrication, and wear. This paper presents an alternative mechanism that is functionally equivalent to a classical flywheel while relying exclusively on limited-stroke flexure joints. This novel one-degree-of-freedom zero-force mechanism has no wear and requires no lubrication: it is thus compatible with extreme environments, such as vacuum, cryogenics, or ionizing radiation. The mechanism is composed of two coupled pivoting rigid bodies whose individual angular momenta vary during motion but whose sum is constant at all times when the pivoting rate is constant. The quantitative comparison of the flexure-based flywheel to classical ones based on a hollow cylinder as inertia shows that the former typically stores 6 times less angular momentum and kinetic energy for the same mass while typically occupying 10 times more volume. The freedom of design of the shape of the rigid bodies offers the possibility of modifying the ratio of the stored kinetic energy versus angular momentum, which is not possible with classical flywheels. For example, a flexure-based flywheel with rigid pivoting bodies in the shape of thin discs stores 100 times more kinetic energy than a classical flywheel with the same angular momentum. A proof-of-concept prototype was successfully built and characterized in terms of reaction moment generation, which validates the presented analytical model.

Most haptic actuators available on the market today can generate only a single modality of stimuli. This ultimately limits the capacity of a kinaesthetic haptic controller to deliver more expressive feedback, requiring a haptic controller to integrate multiple actuators to generate complex haptic stimuli, with a corresponding complexity of construction and control. To address this, we designed a haptic controller to deliver several modalities of kinaesthetic haptic feedback using a single actuator: a flywheel, the orientation of which is controlled by two gimbals capable of rotating over 360 degrees, in combination with a flywheel brake. This enables the controller to generate multiple haptic feedback modalities, such as torque feedback, impact simulation, low-frequency high-amplitude vibrations, inertial effects (the sensation of momentum), and complex haptic output effects such as the experience of vortex-like forces (whirl effects). By combining these diverse haptic effects, the controller enriches the haptic dimension of VR environments. This paper presents the device’s design, implementation, and characterization, and proposes potential applications for future work.

• First proposal of high-temperature superconducting electric flywheel energy storage system. • The system can self-stabilize suspension without the need for active control. • Comparative analysis of the performance of two structures. • Has practical engineering application value. This article presents a high-temperature superconducting flywheel energy storage system with zero-flux coils. This system features a straightforward structure, substantial energy storage capacity, and the capability to self-stabilize suspension and guidance in both axial and radial directions. The article provides an introduction to the system's structure and principle. Firstly, it analyzes the model mechanism and dynamic electromagnetic performance of the 8-shaped coil without cross connection structure while validating its accuracy through comparison with simulation results. Subsequently, it examines the electromagnetic performance of the cross-connected structure, demonstrating its superior performance compared to that of the non-cross-connected structure. These research findings serve as a valuable reference for designing high-temperature superconducting electric flywheel energy storage systems. [ABSTRACT FROM AUTHOR]

We evaluated the effects of post-activation performance enhancement through flywheel exercise with varying inertial loads compared to traditional resistance exercise on countermovement jump performance and muscle recruitment. In a randomized crossover design, 13 trained men completed four main experimental trials after three familiarization sessions. These conditions included a traditional trial consisting of 5 sets of 1 repetition using the Smith machine (SM) squat at 90% 1RM, and three flywheel ergometer trials. Each flywheel protocol consisted of 3 sets of 8 repetitions with 3-minute rest intervals between sets, utilizing one of three inertial loads (0.0465, 0.0784, and 0.1568 kg · m 2 for light, moderate, and heavy, respectively). Participants performed countermovement jumps before (baseline), immediately after (0 minute), and at the fourth (+4 minutes), eighth (+8 minutes), and twelfth (+12 minutes) minute following exercise. Compared to baseline, jump height was higher at +4 minutes for SM squats (p = 0.009). All flywheel conditions exhibited higher jump heights at +4 minutes (p < 0.05), +8 minutes (p < 0.001), and +12 minutes (p < 0.001) compared to baseline. Additionally, moderate and heavy loads resulted in higher jump heights at 0 minute (both p < 0.001). Integrated electromyographic activity values, a proxy for muscle recruitment, were significantly higher for the gluteus maximus muscle at both +8 minutes and +12 minutes for moderate (both p = 0.004) and heavy loads (p ≤ 0.002) compared to SM squats. Overall, flywheel protocols produce greater post-activation performance enhancement, extend the time window for improvement, and recruit more active musculature compared to heavy-load SM squats, particularly with heavier loads acting as a stronger preload stimulus., Competing Interests: The authors declare no conflict of interest., (Copyright © Institute of Sport – National Research Instutite.)

Flywheel is an important component for the canned motor reactor coolant pump (RCP). The flywheel of horizontal canned motor reactor coolant pump (HRCP) is different from RCP's flywheel. Its clearance width or different thermal conductivity structure would affect the flow structure of flywheel clearance flow, and then affect temperature distribution of the clearance, which would further affects the life and stability of flywheel. Therefore, it is necessary to analyze the flow and heat transfer characteristics of flywheel clearance flow in detail. This paper applies a Detached Eddy Simulation (DES) method to study the flywheel clearance flow of HRCP. The results show that the DES method can capture the small-scale vortex structure in turbulence Taylor-Couette flow and then give a more refined flow field morphology. The authors further study the regularity of flywheel clearance flow with different thermal conductivity structure, and the results indicate that optimizing thermal conductivity structure can effectively reduce flywheel's temperature. The authors also investigate the heat dissipation mechanism of different flywheel clearance structures. [ABSTRACT FROM AUTHOR]

A novel variable inertia flywheel that uses the mass of a rotating hydraulic fluid is proposed in this paper. In contrast to variable inertia flywheels that use solid masses, this flywheel stands out for its simplicity. In contrast to many other common energy storages, it does not require any environmentally harmful, rare or expensive materials. The basic working principle and the equations that cover the hydraulic behaviour, the pneumatic behaviour and the energy from angular momentum are introduced. These equations are applied to the geometry of the proposed flywheel concept, which allows quantifying the pressures that act on the different mechanical flywheel components. These pressures, together with the centrifugal acceleration from rotation, lead to the loads that have to be withstood by the mechanical components. A simple method for quantifying these loads, and for dimensioning the mechanical components, allows deriving the stationary masses and inertias. A parameter study is conducted, in which different parameters of the flywheel are varied in order to find the maxima in energy density and specific energy. The results of this parameter study reveal that the proposed hydraulic variable inertia flywheel is a very simple and safe energy storage that could provide AC power systems with inertia and control power to support their frequency. • A hydraulic variable inertia flywheel for energy storage in e.g. power systems. • This flywheel does not require environmentally harmful materials. • It is very simple and hence wear-resistant. • A hydraulic fluid acts as movable mass. • It works entirely passive, i.e. it requires neither controls nor any communication. [ABSTRACT FROM AUTHOR]

• A new strategy is proposed for vibration control of flexible pendulums. • We introduce a flywheel to control flexible pendulum vibration. • The control method has robustness and is effective for nonlinear forced vibration. • An experiment platform is built to validate the proposed control strategy. Flexible inverted pendulums have found wide applications in mechanical systems, but their stability is susceptible to external disturbances. In this study, a new strategy that employs a flywheel to suppress vibration of flexible inverted pendulums is proposed. We develop the theoretical dynamic model of flexible pendulums with a flywheel by the Euler-Bernoulli beam theory, where the axial displacement of the pendulum and geometric nonlinearities are considered. An active control method based on the Bézier trajectory is proposed, where the acceleration of the flywheel is set as the input. Additionally, the equivalent damping ratio of the system including flywheel's motion is derived. The relationship between the parameters in the control equation and the suppression effect is obtained through the simulation of the equivalent damping ratio. Then, an experimental platform is built. The experimental results show that the present control strategy has good suppression effect on the vibration of the flexible inverted pendulums when selecting appropriate parameters. Meanwhile, the results of anti-disturbance test show that the present method has a certain robustness. Finally, the simulation results show that this strategy is also effective for nonlinear forced vibration under different excitation frequencies. [ABSTRACT FROM AUTHOR]