Статті в журналах: "SWING STABILITY"

1

Gonzalez-Longatt, Francisco, Choidorj Adiyabazar, and Ernesto Vazquez Martinez. "Setting and Testing of the Out-of-Step Protection at Mongolian Transmission System." Energies 14, no. 23 (December 6, 2021): 8170. http://dx.doi.org/10.3390/en14238170.

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Modern distance relays have integrated numerous protection functions, including power-swing blocking and out-of-step or pole-slip tripping functions. The main purpose of the power-swing blocking function is to differentiate faults from power swings and block distance or other relay elements from operating during stable or unstable power swings. Most power-swing blocking elements are based on traditional methods that monitor the positive sequence impedance rate. The required settings for the power-swing blocking elements could be difficult to calculate in many applications, particularly those where fast swings can be expected. For these cases, extensive stability studies are necessary to determine the fastest rate of possible power swings. This paper presents a detailed step-by-step method for settings calculation of out-of-step (OOS) protection, both blocking and tripping functions considering a generic two-source system. Then the method is applied to define the protection relay settings installed at the interconnection between the Russian and Mongolian power systems, as it is crucial to feed the demand-rich Mongolian power system. In this paper, a specific impedance method is used for defining the OOS protection settings. This paper innovates by testing the settings using the recordings of the major events of 15 September 2018 in two approaches: hybrid co-simulation and cyber-physical. Both tests have demonstrated the appropriate performance of the proposed settings and proving the proposed methodology works appropriately.

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2

Qin, Jian-Hua, Jie Luo, Kai-Chi Chuang, Tian-Syung Lan, Lie-Ping Zhang, and Huai-An Yi. "Stable Balance Adjustment Structure of the Quadruped Robot Based on the Bionic Lateral Swing Posture." Mathematical Problems in Engineering 2020 (August 28, 2020): 1–10. http://dx.doi.org/10.1155/2020/1571439.

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Aiming at the problem that the stability of the quadruped robot is decreased as its leg momentum is too high, a stable balance adjustment structure of the quadruped robot based on the bionic lateral swing posture is proposed. First, the leg structure of the quadruped robot is improved and designed by using the mechanism of the lateral swing posture of the leg of the hoof animal. Then, the D-H method is used to construct the corresponding leg kinematics model and determine the generalized coordinates of the leg joints in the lateral swing posture. The torque expression of the quadruped robot when it is tilted is established. Based on the differential equation of momentum of the hip joint and its static stability analysis, the static stability conditions in the upright posture and the bionic lateral swing posture are given. Finally, the experimental simulation and comparative analysis of the upright posture and the lateral swing posture of the quadruped robot are proposed by using the Adams virtual prototype technology. The simulation results show that as the angle of lateral swing increases, the peak value of the positive flip torque of the quadruped robot body increases accordingly, while the degree of tilt decreases accordingly, which shows that the bionic lateral swing posture of the quadruped robot has higher static stability than the traditional upright posture. This research provides a technical reference for the design and optimization of the offline continuous gait of the robot and the improvement of stability.

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3

Rahmeyer, W. J. "Sizing Swing Check Valves for Stability and Minimum Velocity Limits." Journal of Pressure Vessel Technology 115, no. 4 (November 1, 1993): 406–10. http://dx.doi.org/10.1115/1.2929548.

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Unexpected wear and failure of swing check valves cost power plants and water treatment facilities millions of dollars each year. Operating swing check valves at too low flow velocities can cause the check valve internals to rapidly wear and suddenly fail. Many of the swing check valve failures could have been avoided by the use of a minimum velocity limit or a numerical model to predict the limit of minimum velocity. The following equations and methodology can be used to predict a minimum velocity limit or VMIN for swing check valves. The limit of VMIN is defined as the minimum flow velocity in which the valve disk is fully open and stable without motion. The procedures and equations can also be used to predict the velocity (VOPEN) to just open the disk to any position or angle. The equations presented in this paper are also unique in that they can be applied to swing check valves that have large degrees of disk position or valve opening. The equations are not limited to swing check valves that must have a portion of the valve disk protruding into the flow through the check valve. Although the methodology was developed primarily for horizontal liquid flows, limited testing has shown that the equations can be applied for installations with inclined slopes and for applications with compressible fluids. The following equations were derived from a large data base of tests of different sizes and types of swing check valves. Tables and figures are presented to support the suggested equations.

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4

Ferraris, Claudia, Gianluca Amprimo, Giulia Masi, Luca Vismara, Riccardo Cremascoli, Serena Sinagra, Giuseppe Pettiti, Alessandro Mauro, and Lorenzo Priano. "Evaluation of Arm Swing Features and Asymmetry during Gait in Parkinson’s Disease Using the Azure Kinect Sensor." Sensors 22, no. 16 (August 21, 2022): 6282. http://dx.doi.org/10.3390/s22166282.

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Arm swinging is a typical feature of human walking: Continuous and rhythmic movement of the upper limbs is important to ensure postural stability and walking efficiency. However, several factors can interfere with arm swings, making walking more risky and unstable: These include aging, neurological diseases, hemiplegia, and other comorbidities that affect motor control and coordination. Objective assessment of arm swings during walking could play a role in preventing adverse consequences, allowing appropriate treatments and rehabilitation protocols to be activated for recovery and improvement. This paper presents a system for gait analysis based on Microsoft Azure Kinect DK sensor and its body-tracking algorithm: It allows noninvasive full-body tracking, thus enabling simultaneous analysis of different aspects of walking, including arm swing characteristics. Sixteen subjects with Parkinson’s disease and 13 healthy controls were recruited with the aim of evaluating differences in arm swing features and correlating them with traditional gait parameters. Preliminary results show significant differences between the two groups and a strong correlation between the parameters. The study thus highlights the ability of the proposed system to quantify arm swing features, thus offering a simple tool to provide a more comprehensive gait assessment.

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5

Remelius, Jebb G., and Richard E. A. van Emmerik. "Time-To-Contact Analysis of Gait Stability in the Swing Phase of Walking in People With Multiple Sclerosis." Motor Control 19, no. 4 (October 2015): 289–311. http://dx.doi.org/10.1123/mc.2013-0106.

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This study investigated timing and coordination during the swing phase of swing leg, body center of mass (CoM) and head during walking people with multiple sclerosis (MS; n = 19) and controls (n = 19). The MS group showed differences in swing phase timing at all speeds. At imposed but not preferred speeds, the MS group had less time to prepare for entry into the unstable equilibrium, as the CoM entered this phase of swing earlier. Time-to-contact coupling, quantifying the coordination between the CoM and the swing foot, was not different between groups. The projection of head motion on the ground occurred earlier after toeoff and was positioned closer to the body in the MS group, illustrating increased reliance on visual exproprioception in which vision of the body in relation to the surface of support is established. Finally, prospective control, linking head movements to the swing foot time-to-contact and next step landing area, was impaired in the MS group at higher gait speeds.

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6

Lee, Ho-Hoon. "A New Motion-Planning Scheme for Overhead Cranes With High-Speed Hoisting." Journal of Dynamic Systems, Measurement, and Control 126, no. 2 (June 1, 2004): 359–64. http://dx.doi.org/10.1115/1.1767855.

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This paper proposes a motion-planning method for a high-performance anti-swing control of overhead cranes, where the motion-planning problem is solved as a kinematic problem. First, an anti-swing regulating control law is proposed based on the Lyapunov stability theorem, where the proposed anti-swing control drives trolley velocity regulating error asymptotically to zero while suppressing load swing rapidly to zero for given arbitrary high-speed hoisting motions. Then a motion-planning scheme is designed based on the concept of minimumtime control, the proposed anti-swing control law, and typical anti-swing crane-operation practices. The motion-planning scheme is free from the usual mathematical constraints in anti-swing control such as small swing angle, small hoisting speed, and small hoisting distance. The effectiveness of the proposed motion planning is shown by generating high-performance anti-swing trajectories with high hoisting speed and hoisting ratio.

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7

Li, Ang, Jin Yun Pu, and Yue Hou. "On the Dynamic Characteristics of Swinging Damaged Rectangular Vessels - An Analysis Employing Collaborative Simulation Based on MATLAB/FLUENT." Applied Mechanics and Materials 253-255 (December 2012): 2145–51. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.2145.

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The existing stability evaluation methods of damaged vessels fell short of the consideration of the turbulent characteristics. Based on the analysis of the coupled relation of the damaged rectangular vessels’ stability and the water dynamic characteristics under different stages, collaborative simulations were made with the aid of MATLAB and FLUENT. Results show that: (1) the swing significantly hinders the turbulent; when the swinging amplitude is comparatively small, its impact is weakened accordingly. (2) When the swinging amplitude increases, in phase , backflow emerges. (3) When the swing frequency is high, an extremum appeared in phase , whose value is determined by the biggest swing angular acceleration.

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8

Al-Badrany, Ahmad A. "Modeling and Simulation of Out of Step Blocking Relay for Power Swing using Concentric Polygons Scheme." Tikrit Journal of Engineering Sciences 17, no. 1 (March 31, 2010): 21–31. http://dx.doi.org/10.25130/tjes.17.1.08.

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This paper investigates a power swing effect on a distance protection relay performance installed on (HV/EHV) transmission line as well as power system stability. A conventional distance relay can’t properly operate under transient stability conditions; therefore, it cause mol-operation, and it will adversely impact on its trip signals. To overcome this problem, the Out Of Step (OOS) relay has modeled and simulated to joint with distance relay to supervise and control on its trip signals response. The setting characteristics technique of the OOS based on concentric polygons scheme method to detect power swing under transient stability situation. This study ia a modeling and simulating using (Maltab\ Simulink) software. A Two relays had been performed and tested with two equivalents network connected to ends. The results of this study showed an activity and reliability of this way to control the distance relay response under a transient stability conditions and it indicated the possibility to find out faults which may occur at period of power swing.

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9

Liu, Peng Fei, Bin Lin, Xiao Feng Zhang, Xu Zhang, and Meng Long Zhou. "Safety and Stability Analysis of the Ship Loader during Shipping." Materials Science Forum 770 (October 2013): 189–93. http://dx.doi.org/10.4028/www.scientific.net/msf.770.189.

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The influence which is brought by the variation law of the whole machines center of gravity position when the telescopic boom and fixed boom at different pitch angles during shipping is been given by using ANSYS and MATLAB. Meanwhile, the influence which the swing arms different pitch angles bring to the safety of the ship loaders own structure is also being analyzed in this paper. Finally, the best placement angle of the ship loaders swing arm is given based on the comprehensive analysis of all factors.

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10

Siragy, Tarique, Allen Hill, and Julie Nantel. "Recovery of dynamic stability during slips unaffected by arm swing in people with Parkinson’s Disease." PLOS ONE 16, no. 4 (April 6, 2021): e0249303. http://dx.doi.org/10.1371/journal.pone.0249303.

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The arm elevation strategy assists in recovering stability during slips in healthy young and elderly individuals. However, in people with Parkinson’s Disease, one of the main motor symptoms affecting the upper limbs is reduced arm swing which intensifies throughout the course of the disease before becoming absent. This holds direct implications for these individuals when encountering slips as the arm elevation strategy is an integral component in the interlimb slip response to restore stability. Arm swing’s effect in recovering from slips in people with Parkinson’s Disease though remains unexamined. Twenty people with Parkinson’s Disease (63.78 ± 8.97 years) walked with restricted and unrestricted arm swing conditions on a dual-belt treadmill where slips were induced on the least and most affected sides. Data were collected on the CAREN Extended System (Motek Medical, Amsterdam, NL). The Margin of Stability, linear and angular trunk velocities, as well as step length, time, and width were calculated. Data were examined during the slipped step and recovery step. The restricted arm swing condition, compared to unrestricted, caused a faster step time during the slipped step. Compared to the most affected leg, the least affected had a wider step width during the slipped step. During the recovery step, the least affected leg had a larger anteroposterior Margin of Stability and longer step time than the most affected. No differences between our arm swing conditions suggests that the normal arm swing in our participants was not more effective at restoring stability after an induced slip compared to when their arm motion was restricted. This may be due to the arm elevation strategy being ineffective in counteracting the slip’s backward destabilization in these individuals. Differences between the legs revealed that our participants were asymmetrically impaired in their slip recovery response.

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11

Ma, Rui, Yayao Zhang, Ziqian Yang, Jürgen Kurths, Meng Zhan, and Congping Lin. "Synchronization stability of power-grid-tied converters." Chaos: An Interdisciplinary Journal of Nonlinear Science 33, no. 3 (March 2023): 032102. http://dx.doi.org/10.1063/5.0136975.

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Synchronization stability is one of central problems in power systems, and it is becoming much more complicated with the high penetration of renewable energy and power electronics devices. In this paper, we review recent work by several nonlinear models for renewable-dominated power systems in terms of multiple timescales, in particular, grid-tied converters within the DC voltage timescale. For the simplest model, a second-order differential equations called the generalized swing equation by considering only the phase-locked loop (PLL) is obtained, which shows a similar form with the well-known swing equation for a synchronous generator in the traditional power systems. With more outer controllers included, fourth-order and fifth-order models can be obtained. The fourth-order model is called the extended generalized swing equation, exhibiting the combined function of grid synchronization and active power balance on the DC capacitor. In addition, a nonlinear model for a two coupled converter system is given. Based on these studies, we find that the PLL plays a key role in synchronization stability. In summary, the value of this paper is to clarify the key concept of the synchronization stability in renewable-dominated power systems based on different nonlinear models, which still lacks systematic studies and is controversial in the field of electrical power engineering. Meanwhile, it clearly uncovers that the synchronization stability of converters has its root in the phase synchronization concept in nonlinear sciences.

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12

Qi, Juntong, Yuan Ping, Mingming Wang, and Chong Wu. "Online Trajectory Planning Method for Double-Pendulum Quadrotor Transportation Systems." Electronics 11, no. 1 (December 24, 2021): 50. http://dx.doi.org/10.3390/electronics11010050.

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This study investigates the trajectory planning problem for double-pendulum quadrotor transportation systems. The goal is to restrain the hook swing and payload swing while achieving precise positioning. An online trajectory planning method with two capabilities—precise positioning and swing suppression—is proposed. The stability and convergence of the system are proved using the Lyapunov principle and the LaSalle’s invariance theory. Simulation results show that the proposed method has excellent control performance.

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13

Wei, Wei, and Xiao Ying Zhao. "Design of an Intelligent Point-to-Point Swing Arm Controller." Advanced Materials Research 706-708 (June 2013): 712–15. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.712.

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The point-to-point swing arm test is very important for large arms which have swing arm movement. Traditional point-to-point swing arm controller is relay control mode. The mode has many shortcomings, such as big volume, high power consumption, low stability, and so on. An intelligent point-to-point swing arm controller, using MCU as the control core, was designed for this reason. It was mainly composed of switch signal detecting module, solenoid valve drive module, USB storage interface module and MCU control module. According to the requirements of test, the controller was able to detect the valid signal of limit switch and control commutation operation of solenoid valve, meanwhile it could record the movement time between one point and another point, the time the arm swayed and the moment information, and these above information would be stored in USB memory. It has some advantages of small size, low power consumption, high stability and flexible functions.

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14

Karssen, J. G. Daniël, Matt Haberland, Martijn Wisse, and Sangbae Kim. "The effects of swing-leg retraction on running performance: analysis, simulation, and experiment." Robotica 33, no. 10 (May 28, 2014): 2137–55. http://dx.doi.org/10.1017/s0263574714001167.

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SUMMARYUsing simple running models, researchers have argued that swing-leg retraction can improve running robot performance. In this paper, we investigate whether this holds for a more realistic simulation model validated against a physical running robot. We find that swing-leg retraction can improve stability and disturbance rejection. Alternatively, swing-leg retraction can simultaneously reduce touchdown forces, slipping likelihood, and impact energy losses. Surprisingly, swing-leg retraction barely affected net energetic efficiency. The retraction rates at which these effects are the greatest are strongly model-dependent, suggesting that robot designers cannot always rely on simplified models to accurately predict such complex behaviors.

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15

Kumano, Teruhisa, Hirokazu Kaneko, Ken-ichi Suzuki, and Yasuji Sekine. "Effect of back swing phenomena upon transient stability." IEEJ Transactions on Power and Energy 109, no. 9 (1989): 403–10. http://dx.doi.org/10.1541/ieejpes1972.109.403.

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16

Béchaud, C., S. Mélen, D. Lasseux, M. Quintard, and C. H. Bruneau. "Stability analysis of a pressure swing adsorption process." Chemical Engineering Science 56, no. 10 (May 2001): 3123–37. http://dx.doi.org/10.1016/s0009-2509(01)00016-1.

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17

Knuesel, Heidi, Hartmut Geyer, and Andre Seyfarth. "Influence of swing leg movement on running stability." Human Movement Science 24, no. 4 (August 2005): 532–43. http://dx.doi.org/10.1016/j.humov.2005.08.002.

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18

Bidram, A., M. E. H. Golshan, and A. Davoudi. "Distributed generation placement considering first swing stability margin." Electronics Letters 48, no. 12 (2012): 724. http://dx.doi.org/10.1049/el.2012.0053.

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19

Baird, Gregory M. "The Pendulum Swing of Revenue Stability and Conservation." Journal - American Water Works Association 102, no. 8 (August 2010): 24–28. http://dx.doi.org/10.1002/j.1551-8833.2010.tb10161.x.

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20

Karunaratne, S., and P. D. C. Wijayatunga. "Synchronous Machine Transient Stability Analysis by an Extension to the Point by Point Method of Solution of the Swing Equation." International Journal of Electrical Engineering & Education 27, no. 1 (January 1990): 37–44. http://dx.doi.org/10.1177/002072099002700107.

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This paper presents a modification to the point by point method of solution of the swing equation, used in the analysis of transient stability of synchronous machines. This modification permits the swing equation to be solved in the presence of electromagnetic damping which is not possible in the original method.

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21

Lee, Ho-Hoon, Yi Liang, and Del Segura. "A Sliding-Mode Antiswing Trajectory Control for Overhead Cranes With High-Speed Load Hoisting." Journal of Dynamic Systems, Measurement, and Control 128, no. 4 (April 25, 2006): 842–45. http://dx.doi.org/10.1115/1.2364010.

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In this paper we propose a sliding-mode antiswing control for overhead cranes. The objective of this study is to realize an antiswing trajectory control with high-speed load hoisting. A sliding-mode antiswing trajectory control scheme is designed based on the Lyapunov stability theorem, where a sliding surface, coupling the trolley motion with load swing, is adopted for a direct damping control of load swing. The proposed control guarantees asymptotic stability while keeping all internal signals bounded. In association with a new antiswing motion planning scheme, the proposed control realizes a typical antiswing trajectory control in practice, allowing high-speed load-hoisting motion and sufficient damping of load swing. The proposed control is simple for a real-time implementation with high-frequency sampling. The effectiveness of the proposed control has been confirmed by experiments.

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22

Rankin, Bradford L., Stephanie K. Buffo, and Jesse C. Dean. "A neuromechanical strategy for mediolateral foot placement in walking humans." Journal of Neurophysiology 112, no. 2 (July 15, 2014): 374–83. http://dx.doi.org/10.1152/jn.00138.2014.

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Stability is an important concern during human walking and can limit mobility in clinical populations. Mediolateral stability can be efficiently controlled through appropriate foot placement, although the underlying neuromechanical strategy is unclear. We hypothesized that humans control mediolateral foot placement through swing leg muscle activity, basing this control on the mechanical state of the contralateral stance leg. Participants walked under Unperturbed and Perturbed conditions, in which foot placement was intermittently perturbed by moving the right leg medially or laterally during the swing phase (by ∼50–100 mm). We quantified mediolateral foot placement, electromyographic activity of frontal-plane hip muscles, and stance leg mechanical state. During Unperturbed walking, greater swing-phase gluteus medius (GM) activity was associated with more lateral foot placement. Increases in GM activity were most strongly predicted by increased mediolateral displacement between the center of mass (CoM) and the contralateral stance foot. The Perturbed walking results indicated a causal relationship between stance leg mechanics and swing-phase GM activity. Perturbations that reduced the mediolateral CoM displacement from the stance foot caused reductions in swing-phase GM activity and more medial foot placement. Conversely, increases in mediolateral CoM displacement caused increased swing-phase GM activity and more lateral foot placement. Under both Unperturbed and Perturbed conditions, humans controlled their mediolateral foot placement by modulating swing-phase muscle activity in response to the mechanical state of the contralateral leg. This strategy may be disrupted in clinical populations with a reduced ability to modulate muscle activity or sense their body's mechanical state.

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Roden-Reynolds, Devin C., Megan H. Walker, Camille R. Wasserman, and Jesse C. Dean. "Hip proprioceptive feedback influences the control of mediolateral stability during human walking." Journal of Neurophysiology 114, no. 4 (October 2015): 2220–29. http://dx.doi.org/10.1152/jn.00551.2015.

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Active control of the mediolateral location of the feet is an important component of a stable bipedal walking pattern, although the roles of sensory feedback in this process are unclear. In the present experiments, we tested whether hip abductor proprioception influenced the control of mediolateral gait motion. Participants performed a series of quiet standing and treadmill walking trials. In some trials, 80-Hz vibration was applied intermittently over the right gluteus medius (GM) to evoke artificial proprioceptive feedback. During walking, the GM was vibrated during either right leg stance (to elicit a perception that the pelvis was closer mediolaterally to the stance foot) or swing (to elicit a perception that the swing leg was more adducted). Vibration during quiet standing evoked leftward sway in most participants (13 of 16), as expected from its predicted perceptual effects. Across the 13 participants sensitive to vibration, stance phase vibration caused the contralateral leg to be placed significantly closer to the midline (by ∼2 mm) at the end of the ongoing step. In contrast, swing phase vibration caused the vibrated leg to be placed significantly farther mediolaterally from the midline (by ∼2 mm), whereas the pelvis was held closer to the stance foot (by ∼1 mm). The estimated mediolateral margin of stability was thus decreased by stance phase vibration but increased by swing phase vibration. Although the observed effects of vibration were small, they were consistent with humans monitoring hip proprioceptive feedback while walking to maintain stable mediolateral gait motion.

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Zhang, Zhongrui, Junqi Shen, Shengsun Hu, Yang Chen, Chengxuan Yin, and Xianzheng Bu. "Optimization of CMT Characteristic Parameters for Swing Arc Additive Manufacturing of AZ91 Magnesium Alloy Based on Process Stability Analysis." Materials 16, no. 8 (April 19, 2023): 3236. http://dx.doi.org/10.3390/ma16083236.

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The droplet transfer behavior and stability of the swing arc additive manufacturing process of AZ91 magnesium alloy based on the cold metal transfer (CMT) technique were studied by analyzing the electrical waveforms and high-speed droplet images as well as the forces on the droplet, and the Vilarinho regularity index for short-circuit transfer (IVSC) based on variation coefficients was used to characterize the stability of the swing arc deposition process. The effect of the CMT characteristic parameters on the process stability was investigated; then, the optimization of the CMT characteristic parameters was realized based on the process stability analysis. The results show that the arc shape changed during the swing arc deposition process; thus, a horizontal component of the arc force was generated, which significantly affected the stability of the droplet transition. The burn phase current I_sc_wait presented a linear function relation with IVSC, while the other three characteristic parameters, i.e., boost phase current I_boost, boost phase duration t_I_boost and short-circuiting current I_sc2, all had a quadratic correlation with IVSC. A relation model of the CMT characteristic parameters and IVSC was established based on the rotatable 3D central composite design; then, the optimization of the CMT characteristic parameters was realized using a multiple-response desirability function approach.

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25

Zhu, Hongbo, Minzhou Luo, Jianghai Zhao, and Tao Li. "Soft landing control strategy for biped robot." Industrial Robot: An International Journal 44, no. 3 (May 15, 2017): 312–23. http://dx.doi.org/10.1108/ir-09-2016-0244.

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Purpose The purpose of this paper was to present a soft landing control strategy for a biped robot to avoid and absorb the impulsive reaction forces (which weakens walking stability) caused by the landing impact between the swing foot and the ground. Design/methodology/approach First, a suitable trajectory of the swing foot is preplanned to avoid the impulsive reaction forces in the walking direction. Second, the impulsive reaction forces of the landing impact are suppressed by the on-line trajectory modification based on the extended time-domain passivity control with admittance causality that has the reaction forces as inputs and the decomposed swing foot’s positions to trim off the forces as the outputs. Findings The experiment data and results are described and analyzed, showing that the proposed soft landing control strategy can suppress the impulsive forces and improve walking stability. Originality/value The main contribution is that a soft landing control strategy for a biped robot was proposed to deal with the impulsive reaction forces generated by the landing impact, which enhances walking stability.

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Zhang, Lijie, Wenbo Fu, Xiaoming Yuan, and Zhaoliang Meng. "Research on Optimal Control of Excavator Negative Control Swing System." Processes 8, no. 9 (September 4, 2020): 1096. http://dx.doi.org/10.3390/pr8091096.

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In order to improve the energy efficiency and dynamic of negative control swing systems of excavators, this paper proposes a technical scheme of adding two PRVs (pressure reducing valves) to main valve pilot control circuit, which can adjust main value opening arbitrarily according to the working condition. A pump-value compound control strategy was formulated to regulate the system power flow. During swing motor acceleration, main pump and the two PRVs are controlled to match system supply flow with motor demand flow, thereby reducing motor overflow and shortening system response time. During swing motor braking, the channel from motor to tank is opened to release hydraulic brake pressure by controlling PRVs before swing speed reduces to zero, which prevents the motor from reversing and oscillating. A simulation model of 37-ton excavator was established, and the control strategy was simulated. The original and optimized performance of the swing system were compared and analyzed, and results show that the application of new scheme with the compound control strategy can reduce overflow and increase braking stability of the swing system. In addition, system response and speed control performance are also improved when excavator performs a single-swing action.

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Ross, James A., Justin W. L. Keogh, and Christian Lorenzen. "Reliability of kettlebell swing one and five repetition maximum." PeerJ 10 (November 21, 2022): e14370. http://dx.doi.org/10.7717/peerj.14370.

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Background Research into the kettlebell swing has increased in the last decade. There has been a paucity of literature assessing an individual’s ability to perform the kettlebell swing exercise. The purpose of this study was to determine the test-retest reliability of the one and five repetition maximum (1RM and 5RM) kettlebell swing. Materials & Methods Twenty four recreational resistance-trained participants performed an isometric mid-thigh pull (IMTP) and two familiarization sessions followed by three test sessions for each RM load approximately one week apart, using a custom-built plate-loaded kettlebell. On each test occasion, subjects completed a series of warm-up sets followed by 3–4 progressively heavier kettlebell swings to a standardized height until 1RM or 5RM was reached. Test-retest reliability was calculated using the intra-class correlation (ICC) and typical error was represented as the coefficient of variation (CV%) with 90% confidence limits (90% CL). The smallest worthwhile change (SWC%) representing the smallest change of practical importance, was calculated as 0.2 × between-subject standard deviation. The relationship of kettlebell swing performance and maximum strength was determined by Pearson correlation with ±90% CL between the absolute peak force recorded during IMTP and 1RM or 5RM. Results Results demonstrated a high test-retest reliability for both the 1RM (ICC = 0.97, 90% CL [0.95–0.99]; CV = 2.7%, 90% CL [2.2–3.7%]) and 5RM (ICC = 0.98, 90% CL [0.96–0.99]; CV = 2.4%, 90% CL [1.9–3.3%]), respectively. The CV% was lower than the SWC for both the 1RM (SWC = 2.8%, 90% CL [1.9–3.5]) and 5RM (SWC = 2.9%, 90% CL [1.9–3.6]) kettlebell swing. The correlation between IMTP absolute peak force and the 1RM (r = 0.69, 90% CL 0.43–0.83) was large and very large for the 5RM (r = 0.75, 90% CL [0.55–0.87]). Conclusions These results demonstrate the stability of 1RM and 5RM kettlebell swing performance after two familiarization sessions. Practitioners can be confident that changes in kettlebell swing 1RM and 5RM performance of >3.6 kg represent a practically important difference, which is the upper limit of the 90% CL.

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Dalvand, Mohsen Moradi, Bijan Shirinzadeh, and Saeid Nahavandi. "Swing-Up and Stability Control of Wheeled Acrobot (WAcrobot)." Automatika 55, no. 1 (January 2014): 32–40. http://dx.doi.org/10.7305/automatika.2014.01.109.

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29

Bruijn, S. M., O. G. Meijer, P. J. Beek, and J. H. van Dieen. "The effects of arm swing on human gait stability." Journal of Experimental Biology 213, no. 23 (November 12, 2010): 3945–52. http://dx.doi.org/10.1242/jeb.045112.

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30

Bidram, Ali, Mohamad-esmail Hamedani-golshan, and Ali Davoudi. "Capacitor Design Considering First Swing Stability of Distributed Generations." IEEE Transactions on Power Systems 27, no. 4 (November 2012): 1941–48. http://dx.doi.org/10.1109/tpwrs.2012.2193603.

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31

Yellajosula, Jaya Raghavendra Arun Kumar, Yawei Wei, Maciej Grebla, Sumit Paudyal, and Bruce A. Mork. "Online Detection of Power Swing Using Approximate Stability Boundaries." IEEE Transactions on Power Delivery 35, no. 3 (June 2020): 1220–29. http://dx.doi.org/10.1109/tpwrd.2019.2941522.

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32

Musavi, M., and N. Narasimhamurthi. "Bounding the short term phase plots of inter-machine swings for determining first swing stability." IEEE Transactions on Circuits and Systems 32, no. 7 (July 1985): 712–18. http://dx.doi.org/10.1109/tcs.1985.1085778.

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33

Cho, Joon-Haeng, and Seung-Min Kwon. "Effect of Swing Fan(Air resistance trainer) on Dynamic Postural Stability at Time of Golf Swing." Journal of Golf Studies 12, no. 1 (March 31, 2018): 17–26. http://dx.doi.org/10.34283/ksgs.2018.12.1.17.

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34

Zhang, Yuzhe, Minghui Li, and Yanchao Fang. "Research and Design of Speed Profiles for Stacker Cranes." Journal of Physics: Conference Series 2562, no. 1 (August 1, 2023): 012062. http://dx.doi.org/10.1088/1742-6596/2562/1/012062.

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Abstract Given the industrial and commercial pursuit of efficiency, it has become urgent to enhance the overall operational efficiency of automated three-dimensional warehouses. This paper focuses on improving the operational efficiency of the stacker in such warehouses. To this end, we deduce the deflection formula and simulate the swing of the stacker to identify the factors that affect its operational stability. Based on these findings, we propose a new speed curve optimization control scheme that properly controls the maximum acceleration and selects an appropriate acceleration change form. This scheme can effectively restrain column swing and improve the stacker’s operational stability, thereby boosting work and production efficiency.

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Li, Xuefei, Jian Li, Lida Su, and Yue Cao. "Control Methods for Roll Instability of Articulated Steering Vehicles." Mathematical Problems in Engineering 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/8041816.

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This study examines the control methods for roll instability of articulated steering vehicles (ASVs) by taking wheel loaders as the research object. An eight-degrees-of-freedom nonlinear dynamics model of ASVs was built on the basis of multibody dynamics. Three methods, namely, active braking (the front and rear axles have the same braking torque), active steering, and adjusting the swing bridge (applying a control torque between the rear body and rear axle), were adopted to analyze the effects on the roll stability of ASVs through the dynamic model. The results show that active braking is conducive to the roll stability of ASVs during turning, active steering can improve the roll stability of ASVs during turning and passing over obstacles, and adjusting the swing bridge can improve the roll stability of ASVs by changing the vehicle posture and the position of the gravity center.

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Chen, Mao-Lin, Chun-Yen Chen, Chien-Hung Wen, Pin-Hao Liao, and Kai-Jung Chen. "Advanced Proportional-Integral-Derivative Control Compensation Based on a Grey Estimated Model in Dynamic Balance of Single-Wheeled Robot." Axioms 10, no. 4 (November 30, 2021): 326. http://dx.doi.org/10.3390/axioms10040326.

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This paper aims to design a one-wheeled robot as regards its pitch freedom and balance control on the one hand and to assess the application feasibility of the GM (1,1) swing estimation controller on the other. System control focuses mainly on one-wheeled robot stability, body swings in position, and speed control. Mathematical modeling and GM (1,1) prediction control are under investigation. The mathematical modeling is firstly conducted through referencing to the Newtonian mechanics and the Lagrange equation, from which the robot transfer function and state-space differential equation are derived. Next, the linear quadratic regulator is applied as the control rule at the balance point. Applying GM (1,1) to assess the robot gyro signal at a dynamic state is a discussion. Next, model reference estimation control is processed, and a mathematical model of the balance control method is completed. Finally, a simulation is conducted to verify the feasibility of the GM (1,1) estimation reference model. The linear quadratic regulator, which is credited with tenacity, can provide pitch swing and balance control of the one-wheeled robot.

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Misiaszek, John E. "Control of Frontal Plane Motion of the Hindlimbs in the Unrestrained Walking Cat." Journal of Neurophysiology 96, no. 4 (October 2006): 1816–28. http://dx.doi.org/10.1152/jn.00370.2006.

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This study describes the patterns of activity of hip abductor and adductor muscles and relates their activity to the frontal plane motions of the hindlimbs during unrestrained walking in the cat to provide insight into the function of these muscles in maintaining stability during walking. Electromyographic activity was recorded from hindlimb muscles while cats walked across a walkway. Four video cameras were used to record the movement of the animal in three dimensions. To further delineate the role of the hip abductors and adductors in regulating frontal plane movements of the legs, medial-lateral translations of the walking surface were periodically introduced. During walking, the hip abducts throughout much of the stance phase and adducts during swing. Normally, the abductors and adductors are co-active during much of the stance phase and are quiescent during swing. Consequently, the adduction observed during swing is likely the result of passive events. It is argued that the activity of the hip abductors during stance phase plays a prominent role in regulating frontal plane motion of the legs during walking. However, when medial-lateral stability is disturbed, both the hip abductors and adductors respond to stabilize the frontal plane motion of the body mass while also adjusting the frontal plane swing trajectory and subsequent paw placement. The balance corrective reactions observed in the cat after medial-lateral perturbations of the support surface reasonably approximate the reactions observed previously in humans, indicating that the cat is a reasonable model to explore the neural mechanisms of lateral stability during walking.

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38

Wang, Jianli, Shenghai Wang, Haiquan Chen, Anqi Niu, and Guoliang Jin. "Dynamic Modeling and Analysis of the Telescopic Sleeve Antiswing Device for Shipboard Cranes." Mathematical Problems in Engineering 2021 (February 18, 2021): 1–15. http://dx.doi.org/10.1155/2021/6685816.

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In order to explore the dynamic characteristics of the telescopic sleeve antiswing device for shipboard cranes under coupling excitation, a three-dimensional dynamic model of the ship crane telescopic sleeve antiswing device is established in this study, and the accuracy of the model is verified through experiments. By dynamic analysis, the influence of sleeve extension and contraction, damper parameters, and ship excitation on the payload swing is found; meanwhile, the influence of payload swing on ship stability is discovered. At the same time, the simulation results show that the three-dimensional dynamic model can accurately simulate the swing reduction characteristics of the antiswing device. The in-plane and out-plane angles of the swing are reduced by 70% and 90%. The research results have great significance to further explore the antiswing mechanism and structural design of the mechanical antiswing device.

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39

Suzuki, Soichiro, Masamichi Takada, and Yuta Iwakura. "Stability Control of a Three-Dimensional Passive Walker by Periodic Input Based on the Frequency Entrainment." Journal of Robotics and Mechatronics 23, no. 6 (December 20, 2011): 1100–1107. http://dx.doi.org/10.20965/jrm.2011.p1100.

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This study proposes a new control that stabilizes a three-dimensional (3D) passive walker without torque input at knees and ankles joints by using entrainment and a mechanical oscillator. It is difficult to stabilize a 3D biped passive walker in different environments because the range of initial conditions for stable walking is limited, so we designed a 3D biped passive walker as a passive walking platform by considering the results of human gait analysis to make the success of passive walking high. The stability of this platform was analytically determined by analyzing the frontal movement limit cycle. In the new control, the frontalmovement period is synchronized with the swing-leg period by a mechanical oscillator on the top of the walker. The mechanical oscillator controller generates a target path to synchronize oscillatormovement with swing-leg movement using frequency entrainment. The walker is stabilized when the frontal movement period was synchronized with the swing-leg period by periodic input generated by the mechanical oscillator. It was experimentally found consequently that the walker was stabilized on different slopes and flat floors.

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Jagodinsky, Adam E., Christopher Wilburn, Nick Moore, John W. Fox, and Wendi H. Weimar. "Ankle Bracing Alters Coordination and Coordination Variability in Individuals With and Without Chronic Ankle Instability." Journal of Sport Rehabilitation 30, no. 1 (January 1, 2021): 62–69. http://dx.doi.org/10.1123/jsr.2019-0380.

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Context: Ankle bracing is an effective form of injury prophylaxis implemented for individuals with and without chronic ankle instability, yet mechanisms surrounding bracing efficacy remain in question. Ankle bracing has been shown to invoke biomechanical and neuromotor alterations that could influence lower-extremity coordination strategies during locomotion and contribute to bracing efficacy. Objective: The purpose of this study was to investigate the effects of ankle bracing on lower-extremity coordination and coordination dynamics during walking in healthy individuals, ankle sprain copers, and individuals with chronic ankle instability. Design: Mixed factorial design. Setting: Laboratory setting. Participants: Forty-eight recreationally active individuals (16 per group) participated in this cross-sectional study. Intervention: Participants completed 15 trials of over ground walking with and without an ankle brace. Main Outcome Measures: Coordination and coordination variability of the foot–shank, shank–thigh, and foot–thigh were assessed during stance and swing phases of the gait cycle through analysis of segment relative phase and relative phase deviation, respectively. Results: Bracing elicited more synchronous, or locked, motion of the sagittal plane foot–shank coupling throughout swing phase and early stance phase, and more asynchronous motion of remaining foot–shank and foot–thigh couplings during early swing phase. Bracing also diminished coordination variability of foot–shank, foot–thigh, and shank–thigh couplings during swing phase of the gait cycle, indicating greater pattern stability. No group differences were observed. Conclusions: Greater stability of lower-extremity coordination patterns as well as spatiotemporal locking of the foot–shank coupling during terminal swing may work to guard against malalignment at foot contact and contribute to the efficacy of ankle bracing. Ankle bracing may also act antagonistically to interventions fostering functional variability.

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Zheng, Kunyao, and Mingming Xu. "Design and Thermal Stability Analysis of Swing Micro-Mirror Structure for Gravitational Wave Observatory in Space." Machines 9, no. 5 (May 18, 2021): 104. http://dx.doi.org/10.3390/machines9050104.

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A kind of swing micro-mirror structure with high stability for gravitational wave observatory in space is proposed in this paper. As the key interface instrument in the gravitational wave observatory, the swing micro-mirror structure plays a very important role. Firstly, the 3D model of the mechanism is designed and established. Then, the solution method of the index of stability, pointing jitter, is researched. After that, the thermal stability and the first-order natural frequency of the mechanism are researched via finite element analysis. The first-order natural frequency of the mechanism is 247.55 Hz, which can meet the requirements of the design. It can be seen from the results of the simulation, the amplitude spectral density of the mirror angle deviation is 3.975 nrad/√Hz when the range of temperature variation is 0.1 °C, which is able to meet the requirements of the design. The thermal stability has a closed relationship with the structural stability around the X-axis. In addition, this article also studies the thermal stability of the mechanism in the case of temperature changes in different directions. It is found that the thermal stability of the mechanism around the Y-axis would be significantly affected by the temperature changes along the Y-axis.

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42

Gryc, Tomáš, Jitka Marenčáková, Matěj Brožka, and František Zahálka. "GOLF SWING VARIABILITY IN ELITE FEMALE JUNIOR GOLFERS." Lékař a technika - Clinician and Technology 49, no. 3 (March 19, 2020): 87–91. http://dx.doi.org/10.14311/ctj.2019.3.03.

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The aim of the study was to determine the variability of golf swing execution in lower and upper body parameters for two golf clubs. Eleven elite female golfers of junior age volunteered in the study and performed 10 trials with mid-iron and with driver at laboratory conditions. A 3D motion capture system was used to measure the lower and upper body movement parameters and club head speed. To assess variability, the coefficient of variation (CV%) and biological coefficient of variation (BCV%) were calculated. Two-tailed t test was used to identify differences between mid-iron and driver variability for each selected kinematic parameter. Any significant difference in variability of kinematics parameters was found between mid-iron club and driver club. However, for both clubs, we found high stability of performance in timing parameters and of lower limbs kinematic parameters at three selected moments of the golf swing. We conclude that timing stability may be the key to achieve the effective and repeatable golf swing in both golf clubs types and that high intra-individual variability of performance may be due to large age range in the study group.

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43

Lee, Kyumin, Laeyong Jung, and Hyunsang Hwang. "Study of high-pressure hydrogen annealing effects on InGaZnO thin-film transistors." Applied Physics Letters 121, no. 7 (August 15, 2022): 072104. http://dx.doi.org/10.1063/5.0098444.

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High-pressure hydrogen annealing (HPHA) treatment is an effective hydrogen doping method to improve electrical characteristics and stability of InGaZnO (IGZO) thin film transistors (TFTs). The HPHA effects on IGZO TFTs under various pressure conditions were investigated using analytical techniques. Drive current, field effect mobility, subthreshold swing, and bias stress stability of IGZO TFTs were significantly improved as the HPHA pressure was increased up to 20 atm. To analyze the performance enhancement, secondary ion mass spectroscopy, capacitance–voltage analysis, and x-ray photoelectron spectroscopy analysis techniques were performed. As a result, it was confirmed that doped hydrogen is combined with interface trap sites and oxygen vacancy related bulk defect sites, leading to improved subthreshold swing and bias stress stability. Furthermore, bulk trap passivation also contributes to high carrier density, thereby increasing driving current and field effect mobility. With increasing HPHA pressure condition, these effects of trap passivation and increase in the carrier density are more effective due to the heavily injected hydrogen.

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44

Zhang, Xue-Liang, Chun-Yu Zhao, and Bang-Chun Wen. "Theoretical and Experimental Study on Synchronization of the Two Homodromy Exciters in a Non-Resonant Vibrating System." Shock and Vibration 20, no. 2 (2013): 327–40. http://dx.doi.org/10.1155/2013/472407.

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In this paper we give some theoretical analyses and experimental results on synchronization of the two non-identical exciters. Using the average method of modified small parameters, the dimensionless coupling equation of the two exciters is deduced. The synchronization criterion for the two exciters is derived as the torque of frequency capture being equal to or greater than the absolute value of difference between the residual electromagnetic torques of the two motors. The stability criterion of synchronous state is verified to satisfy the Routh-Hurwitz criterion. The regions of implementing synchronization and that of stability of phase difference for the two exciters are manifested by numeric method. Synchronization of the two exciters stems from the coupling dynamic characteristic of the vibrating system having selecting motion, especially, under the condition that the parameters of system are complete symmetry, the torque of frequency capture stemming from the circular motion of the rigid frame drives the phase difference to approach PI and carry out the swing of the rigid frame; that from the swing of the rigid frame forces the phase difference to near zero and achieve the circular motion of the rigid frame. In the steady state, the motion of rigid frame will be one of three types: pure swing, pure circular motion, swing and circular motion coexistence. The numeric and experiment results derived thereof show that the two exciters can operate synchronously as long as the structural parameters of system satisfy the criterion of stability in the regions of frequency capture. In engineering, the distance between the centroid of the rigid frame and the rotational centre of exciter should be as far as possible. Only in this way, can the elliptical motion of system required in engineering be realized.

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45

Bhattacharyya, R. "Behavior of a Rubber Spring Pendulum." Journal of Applied Mechanics 67, no. 2 (April 7, 1998): 332–37. http://dx.doi.org/10.1115/1.1302304.

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The stability of motion of a nonlinear neo-Hookean rubber spring pendulum under a special type of support oscillation is studied. The small swing motion is described by a Mathieu-Hill equation, corresponding stability curves for which are generated in a relevant parametric plane with a stability criterion obtained earlier. Autoparametric resonance in the special case of linearized motions is found to occur, as usual. [S0021-8936(00)00801-1]

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46

Martin, Gulan, Salaj Michal, and Rohal'-Ilkiv Boris. "Achieving an Equilibrium Position of Pendubot Via Swing-Up and Stabilizing Model Predictive Control." Journal of Electrical Engineering 65, no. 6 (January 31, 2015): 356–63. http://dx.doi.org/10.2478/jee-2014-0058.

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Abstract In this paper, a complex control strategy to swing-up and balance the under-actuated pendubot system in one of its unstable equilibrium positions is presented. The initial swing-up maneuver is performed using an energy-based approach. For the purposes of stabilizing the system in its mid unstable equilibrium position a model predictive controller based on optimal control law with integral action is proposed. Satisfaction of constraints is ensured by introducing perturbations in the LQ control law acting as corrections when input amplitude/rate bounds are to be exceeded. The stability issue is addressed via additional constraints imposed on the terminal set. The emphasis of the paper is on the experimental realization of the pendubot swing-up followed by its balancing, which reveals the accuracy of the proposed control scheme.

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47

Nguyen, Ngoc Hung, Van Phan Do, and Hoa Tien Vu. "Estimating Disturbance Torque Effects on the Stability and Control Performance of Two-Axis Gimbal Systems." Journal of the Russian Universities. Radioelectronics 25, no. 4 (September 29, 2022): 63–71. http://dx.doi.org/10.32603/1993-8985-2022-25-4-63-71.

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Introduction. Two-axis gimbal systems are applied for stabilizing and controlling the line of sight (LOS) of an optical or imaging system mounted on a moving vehicle. Gimbal systems are intended to isolate various disturbance torques and control the LOS toward the direction of a target. Two-axis gimbals can be of two main types, namely Yaw-Pitch and Swing-Roll type. In this article, we focus on investigating mathematical models of two-axis gimbals, which describe the impact of cross-disturbance torques on their stability and control performance. Simulations were conducted to compare advantages and disadvantages of the two types of two-axis gimbals.Aim. To study mathematical models describing the impact of cross-disturbance torques on the stability and control performance of two-axis gimbals.Materials and methods. Mathematical models of two-axis gimbal systems were synthesized by the Lagrange method. The operation of two-axis gimbal systems was simulated in the Matlab-Simulink environment. Results. Mathematical models and structural diagrams of the synthesized Yaw-Pitch and Swing-Roll gimbals were obtained. The conducted simulations of typical cases revealed different cross-disturbance effects.Conclusion. Motion equations for Swing-Roll and Yaw-Pitch gimbals were derived using similar methodology. The impact of cross-disturbance torques on gimbal systems was evaluated. The obtained results form a basis for selecting an optimal structure of tracking systems meeting the desired characteristics.

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48

YAZDI, NAVID, M. AHMADI, G. A. JULLIEN, and M. SHRIDHAR. "A LARGE-SWING HIGH-DRIVE CMOS BUFFER AMPLIFIER FOR A WIDE LOAD RANGE." Journal of Circuits, Systems and Computers 02, no. 04 (December 1992): 323–33. http://dx.doi.org/10.1142/s0218126692000209.

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A high-swing, high-drive CMOS buffer amplifier, with good stability over a wide range of capacitive and resistive loads, is presented in this paper. A new area efficient output stage with a relatively small compensation capacitor has been used so that the circuit occupies only 120 mils2 in a 3 μm CMOS technology. The buffer has a drive capability of 110 kHz into a 5000 pF load with a rail-to-rail output swing for load resistances greater than 10 kΩ and acceptable total harmonic distortion with loads down to 270 Ω.

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49

Zhang, Menghua, Yongfeng Zhang, Bing Ji, Changhui Ma, and Xingong Cheng. "Modeling and energy-based sway reduction control for tower crane systems with double-pendulum and spherical-pendulum effects." Measurement and Control 53, no. 1-2 (November 28, 2019): 141–50. http://dx.doi.org/10.1177/0020294019877492.

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As typical underactuated systems, tower crane systems present complicated nonlinear dynamics. For simplicity, the payload swing is traditionally modeled as a single-pendulum in existing works. Actually, when the hook mass is close to the payload mass, or the size of the payload is large, a tower crane may exhibit double-pendulum effects. In addition, existing control methods assume that the hook and the payload only swing in a plane. To tackle the aforementioned practical problems, we establish the dynamical model of the tower cranes with double-pendulum and spherical-pendulum effects. Then, on this basis, an energy-based controller is designed and analyzed using the established dynamic model. To further obtain rapid hook and payload swing suppression and elimination, the swing part is introduced to the energy-based controller. Lyapunov techniques and LaSalle’s invariance theorem are provided to demonstrate the asymptotic stability of the closed-loop system and the convergence of the system states. Simulation results are illustrated to verify the correctness and effectiveness of the designed controller.

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50

Mollineda, Ramón A., Daniel Chía, Ruben Fernandez-Beltran, and Javier Ortells. "Arm Swing Asymmetry Measurement from 2D Gait Videos." Electronics 10, no. 21 (October 25, 2021): 2602. http://dx.doi.org/10.3390/electronics10212602.

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Анотація:

Arm swing during gait has been positively related to gait stability and gait efficiency, particularly in the presence of neurological disorders that affect locomotion. However, most gait studies have focused on lower extremities, while arm swing usually remains ignored. In addition, these studies are mostly based on costly, highly-specialized vision systems or on wearable devices which, despite their popularity among researchers and specialists, are still relatively uncommon for the general population. This work proposes a way of estimating arm swing asymmetry from a single 2D gait video. First, two silhouette-based representations that separately capture motion data from both arms were built. Second, a measure to quantify arm swing energy from such a representation was introduced, producing two side-dependent motion measurements. Third, an arm swing asymmetry index was obtained. The method was validated on two public datasets, one with 68 healthy subjects walking normally and one with 10 healthy subjects simulating different styles of arm swing asymmetry. The validity of the asymmetry index at capturing different arm swing patterns was assessed by two non-parametric tests: the Mann–Whitney U test and the Wilcoxon signed-rank test. The so-called physiological asymmetry was observed on the normal gait sequences of both datasets in a statistically similar way. The asymmetry index was able to fairly characterize the different levels of asymmetry simulated in the second set. Results show that it is possible to estimate the arm swing asymmetry from a single 2D gait video, with enough sensitivity to discriminate anomalous patterns from normality. This opens the door to low-cost easy-to-use mobile applications to assist clinicians in monitoring gait condition in primary care (e.g., in the elderly), when more accurate and specialized technologies are often not available.

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