Swing Motion Research Articles

Enhanced vehicle shimmy performance using inerter-based suppression mechanism

Shimmy may occur in the vehicle normal driving process, which is a harmful motion and should be controlled in practical engineering. In order to improve the vehicle driving and handling stability, four kinds of passive inerter-based suppression mechanisms are proposed and applied in the vehicle suspension to improve its shimmy performance. The configurations S1 and S2 are composed of one inerter and one damper, which are in parallel-connected and series-connected, respectively, furthermore, an auxiliary spring is added to constitute configurations S3 and S4. Combined with the magic nonlinear tire model, the vehicle shimmy model with four inerter-based suppression mechanisms is established using Lagrange theory, its shimmy performance is studied using bifurcation analysis method, the stable area and limit cycle oscillation (LCO) magnitude of the system are obtained and compared with those of the original suspension system. The effect of the structural parameters of the inerter-based suppression mechanisms on the vehicle shimmy performance is analyzed, and the structural parameter optimization of the inerter-based suppression mechanism is investigated. The results show that the only parallel-connected and series-connected configurations S1 and S2 have little improvement effect on the vehicle shimmy performance. As the configurations S3 and S4 are used, the unstable area dominated by left and right steering shimmy reduces, the shimmy occurred vehicle velocity range becomes narrower and the maximum LCO magnitude of the front wheel swing motion becomes smaller, which suppresses the vehicle shimmy effectively and clarifies the benefits of the inerter and the necessity of adding the auxiliary spring. In addition, larger inertance of the inerter and smaller stiffness of the auxiliary spring is beneficial to improve the vehicle shimmy performance. The optimized structural parameters of the configurations S3 and S4 are obtained, which maintain the vehicle shimmy system stable, and further shorten the time for the vehicle shimmy system to reach stability. Therefore, the inerter-based suppression mechanism can effectively restrain the vehicle shimmy motion and give guiding significance for the design of vehicle shimmy suppression mechanism.

Robustness Analysis for a Nonlinear Gantry Crane System Using Fuzzy Logic Controller

Gantry cranes are equipment used for loading and unloading heavy items. They are majorly used in the industries and shipyards to transport heavy loads. Generally, operational requirements for the gantry crane is to move the load with minimum swing angle, high positioning accuracy and with minimum time possible. External and environmental disturbances affects the performance of the gantry crane when in operation. Control of the gantry crane system has over many years attracted many researchers with interest in designing a robust gantry crane system free of swing motions. Several researchers have proposed the use of PID controllers. However, their control methods have limitations among them, being sensitive to disturbances. Thus, for the crane to operate effectively, trolley positioning and swing motion of the load need to be controlled. The main goal of this research is to design a robust control mechanism for the gantry crane system against swing motion due to uncertainties. The gantry crane system has been designed using mathematical modeling with assumption that the load is attached to a trolley using one rope and moves in 2D plane. The robustness analysis of the Fuzzy Logic Controller (FLC) has been simulated in MATLAB/Simulink environment and comparison done with auto-tuned PID controller in environment where external disturbances are present. Various transient response performance indices specifications have been used to determine the effectiveness of the controller model. The final results have demonstrated that FLC is capable of producing better results of minimizing swing motion as compared to PID controllers.

Design, modeling and experiments of swing L-shape piezoelectric beam applied to tidal and wave energy harvesting

Swing-piezoelectric energy harvesting has the potential to be used for small-scale tidal and wave energy harvesting. A novel method is proposed to capture tidal and wave energy by combining swing motion and piezoelectric elements in this paper. The dynamic equation and electromechanical coupling equation for the Swing L-shaped Beam Piezoelectric Energy Harvester (SLB-PEH) are derived using the Lagrangian equation, and a Simulink-Adams simulation model is constructed. The model's accuracy is confirmed by comparing theoretical, simulated, and experimental outcomes. Furthermore, key parameters' impact on SLB-PEH performance is examined through experiments. The paper introduces an interleaved SLB-PEH to enhance energy capture efficiency within space constraints. It also describes the design of the Integrated Spring Tidal-Wave Piezoelectric Energy Harvester (ISTW-PEH), which is inspired by the interleaved SLB-PEH structure. The experimental results demonstrate that the ISTW-PEH can generate a maximum power output of 13.6 mW at a flow velocity of 0.3 m/s and a maximum power of 57.6 mW under a wave height of 0.08 m and a wave period of 0.08s.

Extracting proficiency differences and individual characteristics in golfers' swing using single-video markerless motion analysis.

In this study, we analyzed golfers' swing movement to extract differences in proficiency and individual characteristics using two-dimensional video data from a single camera. We conducted an experiment with 27 golfers who had a wide range of skill levels, using a 7-iron; we acquired video data with a camera on the sagittal plane. For data extraction, we used pose estimation (using HRNet) and object detection (using DeepLabCut) methods to extract human-joint and club-head data. We examined the relationship between proficiency and individual characteristics vis-à-vis forward tilt angle and club trajectory. The results showed that the stability and reproducibility of the forward tilt angle are characteristics of proficiency. Highly skilled golfers showed low variability and high reproducibility between trials in forward tilt angle. However, we found that club trajectory may not be a characteristic of proficiency but rather an individual characteristic. Club trajectory was divided roughly into clockwise rotation and counterclockwise rotation. Thus, the analysis based on video data from a single markerless camera enabled the extraction of the differences in proficiency and individual characteristics of golf swing. This suggests the usefulness of our system for simply evaluating golf swings and applying it to motor learning and coaching situations.

An affordable and easy-to-use tool to diagnose knee arthritis using knee sound

Arthritis, the most common form of osteoarthritis, affects millions of individuals worldwide. While it can affect any joint in the body, it predominantly affects the hands, neck, back, knees, and hips. Traditional imaging technologies like X-rays are impractical for diagnosing knee pathology and are insufficient for detecting disease symptoms, especially in the early stages of damage. Invasive procedures such as arthroscopy are often required to identify changes, but they are unsuitable for repeated assessments, follow-ups, or monitoring. Vibro-acoustography (VAG), which utilizes vibration and acoustic signals from the human knee during movement, has emerged as a non-invasive diagnostic tool. However, muscle-induced low-frequency irregularities triggered by knee movement significantly impact the accuracy of VAG signals. In this study, a novel machine learning-based approach is introduced for detecting knee osteoarthritis by processing sound signals recorded by a condenser microphone. Knee sounds from both healthy and osteoarthritic patients were captured during knee swing motions (flexion and extension). Three features were extracted from the knee sounds and classified using the Perceptron, MLP, SVM, GRNN, and RBF classifiers. The performance of different features and classifiers was compared, revealing that one feature demonstrated robust results with a high accuracy of 87% and an F1-score of 0.86. Compared to other conventional methods, the proposed approach is characterized by its speed, affordability, portability, and user-friendliness, with the potential for easy development into a mobile application.

Detumbling of Underactuated Tethered Satellite System Based on Hierarchical Sliding Mode Control

Millions of space debris pose a significant risk to operational spacecraft, making active debris removal (ADR) missions an urgent priority. Net capturing is a promising method to remove space debris objects due to its multiple advantages. However, once a target has been captured, a combined tethered system comprising the chaser, the target, and the tethers is formed, which requires effective stabilization. In this paper, stabilization of the entire postcapture system is realized by solely controlling the active chaser satellite. Such a control strategy can attenuate system hardware facilities compared with those by applying additional tether control such as using a winding mechanism, which were mostly discussed in the literature. Further, for the first time, considering the uncertainties during the capture process, including inaccurate target parameters, initial attitude error of the target, and external disturbances, a hierarchical sliding mode controller (HSMC) with two sublayers is developed to detumble this underactuated system. Additionally, a hybrid position controller is proposed to eliminate the undesired swing motion within the system. Numerical simulations demonstrate that HSMC method delivers better performance over the proportional-derivative controller in efficiency and robustness for postcapture stabilization of the combined tethered system. Overall, our proposed control strategy offers a promising solution for future ADR missions, contributing to a safer and more sustainable space environment.

Multimode microdimer robot for crossing tissue morphological barrier

Swimming microrobot energized by magnetic fields exhibits remotely propulsion and modulation in complex biological experiment with high precision. However, achieving high environment adaptability and multiple tasking capability in one configuration is still challenging. Here, we present a strategy that use oriented magnetized Janus spheres to assemble the microdimer robots with two magnetic distribution configurations of head-to-side configuration (HTS-config) and head-to-head configuration (HTH-config), achieving performance of multiple tasks through multimode transformation and locomotion. Modulating the magnetic frequency enables multimode motion transformation between tumbling, rolling, and swing motion with different velocities. The dual-asynchronization mechanisms of HTS-config and HTH-config robot dependent on magnetic dipole-dipole angle are investigated by molecular dynamic simulation. In addition, the microdimer robot can transport cell crossing morphological rugae or complete drug delivery on tissues by switching motion modes. This microdimer robot can provide versatile motion modes to address environmental variations or multitasking requirements.

Multistep conformational changes leading to the gate opening of light-driven sodium pump rhodopsin

Membrane transport proteins require a gating mechanism that opens and closes the substrate transport pathway to carry out unidirectional transport. The "gating" involves large conformational changes and is achieved via multistep reactions. However, these elementary steps have not been clarified for most transporters due to the difficulty of detecting the individual steps. Here, we propose these steps for the gate opening of the bacterial Na+ pump rhodopsin, which outwardly pumps Na+ upon illumination. We herein solved an asymmetric dimer structure of Na+ pump rhodopsin from the bacterium Indibacter alkaliphilus. In one protomer, the Arg108 sidechain is oriented toward the protein center and appears to block a Na+ release pathway to the extracellular (EC) medium. In the other protomer, however, this sidechain swings to the EC side and then opens the release pathway. Assuming that the latter protomer mimics the Na+-releasing intermediate, we examined the mechanism for the swing motion of the Arg108 sidechain. On the EC surface of the first protomer, there is a characteristic cluster consisting of Glu10, Glu159, and Arg242 residues connecting three helices. In contrast, this cluster is disrupted in the second protomer. Our experimental results suggested that this disruption is a key process. The cluster disruption induces the outward movement of the Glu159-Arg242 pair and simultaneously rotates the seventh transmembrane helix. This rotation resultantly opens a space for the swing motion of the Arg108 sidechain. Thus, cluster disruption might occur during the photoreaction and then trigger sequential conformation changes leading to the gate-open state.

Research on the Performance Characteristics and Unsteady Flow Mechanism of a Centrifugal Pump under Pitch Motion

Pitch motion is the key factor affecting the performance characteristics of centrifugal pumps on board ships and exacerbates hydraulic excitation to induce the unsteady vibration of pump units. A hydraulic test platform with swing motion is established to explore the effects of pitch motion on a pump’s performance characteristics. An obvious hump zone exists in the head characteristic curve in the low-flow-rate condition due to the pitch motion. The pump head in the shut-off condition has a significant decrease due to the pitch motion, compared to the static state. The head decrease gradually increases as the maximum pitch angle increases or the pitch period shortens. Specifically, the head in the rated flow condition decreases by 6.3 % to reach a minimum at the maximum pitch angle of 20 degrees in a period of 5 s. Based on a multiple-reference coordinate system, a large eddy simulation with a shear-modified eddy viscosity model is employed to simulate inner flow characteristics under the influence of pitch motion. A distinct vortex flow appears near the blade suction surface and becomes increasingly turbulent as the pitch period shortens. The pitch motion intensifies the unsteady stretching and deformation of vortices. The periodic variations in fluid-induced pressure over time present parabolic features, and the amplitude in the frequency domain reaches its maximum value within a pitch period of 5 s.

GolfMate: Enhanced Golf Swing Analysis Tool through Pose Refinement Network and Explainable Golf Swing Embedding for Self-Training

Digital fitness has become a widely used tool for remote exercise guidance, leveraging artificial intelligence to analyze exercise videos and support self-training. This paper introduces a method for self-training in golf, a sport where automated posture analysis can significantly reduce the costs associated with professional coaching. Our system utilizes a pose refinement methodology and an explainable golf swing embedding for analyzing the swing motions of learners and professional golfers. By leveraging sequential coordinate information, we detect biased pose joints and refine the 2D and 3D human pose estimation results. Furthermore, we propose a swing embedding method that considers geometric information extracted from the swing pose. This approach enables not only the comparison of the similarity between two golf swing poses but also the visualization of different points, providing learners with specific and intuitive feedback on areas that require correction. Our experimental results demonstrate the effectiveness of our swing guide system in identifying specific body points that need adjustment to align more closely with a professional golfer’s swing. This research contributes to the digital fitness domain by enhancing the accuracy of posture analysis and providing a specialized and interpretable golf swing analysis system. Our proposed system offers a low-cost and time-efficient approach for users who wish to improve their golf swing, paving the way for broader applications of digital fitness technologies in self-training contexts.

Correlation between momentum and ball speed in shooting movements of female futsal players

The purpose of this study was to find a correlation between momentum and ball speed in the shooting movements of female futsal players. This study used a correlational research design. Five female futsal players (aged 19) participating in this study performed shooting movements, which were recorded on video for analysis. The shooting movements of female futsal players were analyzed based on swing movements, foot contact with the ball, and body position. Pearson correlation test was used for data analysis. The results showed that the average magnitude of momentum (impact from foot contact with the ball) was 8.14±4.68 Ns and resulted in an average ball speed of 18.51±10.63 m/s. There is a relationship between the amount of momentum and the resulting ball speed (sig < 0.05). The correlation was positive, which shows the direction of a positive relationship so that the greater the momentum, the faster the ball speed. The greatest momentum is 16.49 Ns resulting in the highest ball speed of 37.48 m/s. To generate great momentum and the highest ball speed, the shooting movement is carried out with a backswing flexion angle of 106°, a kicking leg angle of 57°, and a hip and shoulder tilt angle of 14°.

Design and analysis of a microminiature omnidirectional wave energy-harvesting device based on a spatial slider–crank mechanism

Energy-harvesting devices using wave energy and ocean current energy can provide higher endurance and operation capacity for small floating or mobile equipment in offshore operations. In this paper, a microminiature omnidirectional wave energy-harvesting device based on a spatial slider–crank mechanism was designed for equipment whose length is less than ordinary ocean wavelength. It can harvest the ocean wave energy from the omnidirectional swing of the buoy and convert the reciprocating swing motion of the buoy into the unidirectional rotation motion of the generator to improve the energy conversion efficiency. The dynamic model and equivalent circuit model of the energy-harvesting device were established by the Lagrangian method and circuit-based analysis method, respectively. The model was simulated, and the effects of parameters such as crank length, wave period, etc. were investigated. The results showed that the device has good energy-harvesting performances, especially in medium and low sea conditions. In addition, the performance of the device can be improved by adjusting the length of the crank and rod.

Thermal annealing promoted room temperature phosphorescence: motion models and internal mechanism.

Thermal annealing has been proven to be an efficient method to optimize the device performance of organic and polymeric opto-electronic materials. However, no detailed information of aggregate structures was obtained for a deeper understanding of what happens during thermal annealing. Herein, through modulation of molecular configurations by tunable linkage positions, and the amplified amplitudes of molecular motions by incorporation of additional methylene units, accurate changes of aggregated structures upon thermal annealing have been achieved, accompanying with the 'turn-on' room temperature phosphorescence (RTP) response by about 4800- and 177-fold increase of lifetimes. The stretching and swing motion models have been proposed, which afforded an efficient way to investigate the science of dynamic aggregation in depth.

Using analytical methods for finding the approximate solutions to fractional differential equations

This essay focuses on studying the nonlinear fractional integral equation. Various methods, including Akbari-Ganji's Method (AGM), Homotopy Perturbation Method (HPM), and Vibrational Iteration Method (VIM), are utilized to obtain its solution. We introduce an innovative approach to obtain rough approximations for fractional differential equations. These equations play a significant role in the field of fluid dynamics and find widespread application. In this article, we have used analytical methods to check the correctness of the answers. Maple mathematical software is used to solve all fractional equations. Ordinary equations and fractional differential equations have connections to entropy, wavelets, and other related concepts. To demonstrate the method, a few examples are employed, chosen for their accuracy and simplicity of implementation. The solutions are explained using convergent series. According to the calculations performed with analytical methods on the fractional integral equations of the nonlinear oscillator, Due to the swing movements of the oscillator, as the swing movement's increase, the velocity gradient becomes an upward trend.

Sex differences regarding the effects of arm swing on ground reaction force and trunk movements between track and field athletes

The purpose of this study was to clarify the sex difference in the effects of arm swing movements of track and field athletes on ground reaction force and trunk movement. Seven male and nine female athletes belonging to a university track and field team were asked to perform arm swings for 10 seconds each under three different conditions (longitudinal, lateral, and original) while in the standing position. Three-dimensional coordinate data for each experimental trial was collected using an automatic optical motion analyser, and ground reaction forces were measured using a force plate. Under the longitudinal condition, the mean acceleration force was greater for males than for females (p < .05), and the operating range of trunk twist angle was significantly greater for females than for males (p < .05). However, under the original condition, there were no significant differences between the sexes in mean acceleration force, but there were significant differences in maximum twist angle and minimum and maximum shoulder abduction angles (p < .05). These results indicate that there are sex differences in trunk movement and ground reaction force depending on the direction of arm swing.

Study on the effect of ocean rolling motion on the thermal–hydraulic performance of supercritical carbon dioxide in horizontal tube

The effect of ocean rolling motion on the flow and heat transfer characteristics of the S-CO2 has been numerically investigated in this article. The results showed that increasing the rolling period makes the influence of rolling motion tend to be gentle. Increasing the maximum rolling angle and the rolling radius will increase the centrifugal and tangential forces on the fluid inside the tube, further making the swing motion of the flow field become more intense. Thus, this directly results in the tube wall temperature oscillation of 10 K to 50 K as well as the total pressure drop fluctuation of about 6%. In addition, the effect of three spatial positions relative to the rolling axis is also investigated. This research work can provide a theoretical reference for the development of marine equipment.

Numerical Study of Aerodynamic Characteristics of No-Swinging and Free-to-Swing Cross Parachute

During wind-tunnel experiments on parachutes, it is common to either fix the apex of the canopy to maintain a specific angle of attack or only fix the confluence point of the suspension lines to allow the canopy to move freely. These no-swinging and free-to-swing conditions affect considerably the aerodynamic characteristics of the parachute. This paper investigates the influence of these conditions on the aerodynamic characteristics and dynamic motion characteristics of both symmetric cross parachutes with eight equal suspension lines, and asymmetric cross parachutes with two (of eight) shortened suspension lines. The research reveals that the canopy of a no-swinging cross parachute exhibits a spinning motion around its axis. The free-to-swing parachute undergoes a conical swing motion around the suspension-line confluence point. The frequency of spin and conical swing increases in proportion to . The magnitude and direction of the lift force varies periodically owing to the conical swing of the free-to-swing parachute. Conversely, the no-swinging parachute, at a fixed angle of attack, maintains a comparatively stable lift force. The free-to-swing asymmetric cross parachute produces a stronger lift force because of the larger swing angle compared to the symmetric parachute. The resultant asymmetry in the aerodynamic shape caused by the shortening of suspension lines has minimal effect on aerodynamic characteristics.

Accuracy of badminton swing action recognition based on fractional time network

To improve the recognition accuracy of badminton players’ swing movements, this study proposes a single inertial sensor based method for badminton swing movement recognition. This article proposes a badminton racket-mounted data gathering system with a single inertial sensor and proposes a real-time motion data flow-based window segmentation technique to capture motion data. On this basis, a two-layer classifier recognition model based on C4.5 Decision Tree (C4.5 T) algorithm and Random Forest (RF) method is constructed to recognize swing technical actions. Using the C4.5 T to identify the swing style of athletes; The RF method is used to recognize the swing technical action. The final experiment showed that the method studied achieved a recognition accuracy of 95.36% for six common swing movements. The proposed model has good application prospects in the recognition of badminton swing movements. However, due to the limitations of the experimental conditions, the recognition effect of this method on more complex swing movements needs to be further verified.

The Dynamic Behavior of a Single Semiflexible Ring Chain in a Linear Polymer Matrix

We studied the dynamic behavior of a single semiflexible ring in linear chain matrix based on a coarse-grained model using the molecular dynamics simulation approach. We found that that ring chains’ hollow centers are frequently filled with linear chains. However, as the rigidity of the linear chains increases, the linear chains arranged parallel to each other and the ring chain are temporary caged. As a result, the swing movement in the normal direction of the ring is significantly limited, and the relaxation time in the normal direction increases significantly. Our findings can help to understand the physical mechanism of the movement of the ring chain in ring–linear polymer blends at the microscopic level.

Biomechanical Analysis of Golf Swing Motion Using Hilbert-Huang Transform.

In golf swing analysis, high-speed cameras and Trackman devices are traditionally used to collect data about the club, ball, and putt. However, these tools are costly and often inaccessible to golfers. This research proposes an alternative solution, employing an affordable inertial motion capture system to record golf swing movements accurately. The focus is discerning the differences between motions producing straight and slice trajectories. Commonly, the opening motion of the body's left half and the head-up motion are associated with a slice trajectory. We employ the Hilbert-Huang transform (HHT) to examine these motions in detail to conduct a biomechanical analysis. The gathered data are then processed through HHT, calculating their instantaneous frequency and amplitude. The research found discernible differences between straight and slice trajectories in the golf swing's moment of impact within the instantaneous frequency domain. An average golfer, a single handicapper, and three beginner golfers were selected as the subjects in this study and analyzed using the proposed method, respectively. For the average golfer, the head and the left leg amplitudes of the swing motions increase at the moment of impact of the swings, resulting in the slice trajectory. These results indicate that an opening of the legs and head-up movements have been detected and extracted as non-linear frequency components, reviewing the biomechanical meaning in slice trajectory motion. For the single handicapper, the hip and left arm joints could be the target joints to detect the biomechanical motion that triggered the slice trajectory. For the beginners, since their golf swing forms were not finalized, the biomechanical motions regarding slice trajectory were different from each swing, indicating that beginner golfers need more practice to fix their golf swing form first. These results revealed that our proposed framework applied to different golf levels and could help golfers to improve their golf swing skills to achieve straight trajectories.