Motion System Research Articles

Projectile motion under quadratic air resistence via multistep-differential transformation method

The projectile motion system was examined in this study when air resistance was present (we only looked at the situation of quadratic air resistance). First, we used Newtonian mechanics to derive the equation governing the system. Second, the study focused on the projectile motion’s characteristics, namely its maximum height and maximum horizontal range. Additionally, we used simulation plots to apply the Differential Transform Method (DTM) and the Multistep Differential Transform Method (Ms-DTM) to solve the equations found. This allowed us to discuss the projectile’s trajectory. We computed the flying time and the maximum range by comparing our findings with experimental data from published research. In the end, the absolute errors were computed to find the optimal numerical approach to solve this problem.

Research on Automatic Grasping System of Industrial Robot Based on Computer Vision

The first paper focuses on YOLOv5 model optimization for advanced image processing, cu. The second paper explores low-cost machine vision cameras, achieving 97% accuracy in grasp verification. The third paper implements SVM algorithm with ArUco markers for hand-eye calibration. The adjustments made to the connection of sensing and motion system significantly expanded the scope of the detection while maintain the accuracy of grasping.. The fourth and fifth experiments improved the existing models by adding coordinate systems and wrist-mounted cameras separately. By doing so, it is possible to catch clearer and more precise pictures of the target objects. The final two research focus on promoting the automatic aspect of the system. Utilizing two networks and corresponding datasets, for one; employing multiple innovative vision-based techniques, for another. These studies collectively demonstrate the advancement in machine vision-based robotic grasping through various technical approaches, including model optimization, hardware evaluation, and algorithm implementation for improved accuracy and efficiency.

Phobia situations increase body sway in young adults

BACKGROUND: Recent studies have analyzed the influence of emotional state. However, most of these studies employed questionnaires exclusively and were conducted outside the context of the phobic episode. AIM: The study aimed to investigate how phobia interferes with body sway in younger adults. METHOD: Thirty-seven adults participated in the study and underwent a postural control assessment in which participants should maintain an upright static position while watching a video. They performed three conditions: pre-phobia, which involved viewing neutral images; phobia phase, which involved viewing images based on the previous phobia and fear questionnaire; and post-phobia phase, which involved viewing neutral images. Body sway was measured using a Vicon Motion System® - 200 Hz. Three passive markers were positioned on pre-determined anatomical landmarks of the body. The following parameters were analyzed: anterior-posterior and medial-lateral amplitude, mean velocity and displacement, and the entire oscillation trajectory. RESULTS: The ANOVA indicated the effect of phobia by analyzing the conditions of anterior-posterior displacement (F2,22 = 10.067, p <0.001) and mean velocity (F2,22 = 11.142, p <0.001). The phobia condition showed higher anterior-posterior displacement and mean velocity values than the pre- and post-phobia conditions (p <0.001). CONCLUSION: The findings indicated an increase in body sway in phobia situations, suggesting that individuals should avoid situations requiring balance when exposed to phobic stimuli.

Problem of low-frequency motion cueing along roll on flight simulators

An innovative approach to improve the fidelity of low-frequency lateral motion cueing within full-flight simulators for non-maneuvering aircraft is presented. On the basis of the perception peculiarities by the human vestibular system of movement along the roll, the problem of low-frequency motion cueing of lateral movement by motion systems of flight simulators was formulated and solved. The critical challenge of simulating the set of angular motion cues that pilots perceive during flights is decided. This research highlights two key outcomes. The fourth-order low-pass filter effectively extracts low-frequency motion cues from aircraft motion kinematic parameters, enhancing simulation accuracy. Secondly, proposed method significantly expands the range of simulated motion cues while ensuring their synchronization with high-frequency motion cues along relevant degrees of freedom. This formulation of the problem increases the range of simulated motion cues to ±0,3nz, which practically corresponds to the range of simulated motion cues of a transport aircraft, and thus increases the quality of motion cueing. The implementation of the developed method on the An-72TK-200 full flight simulator confirmed its effectiveness. In conclusion, this study introduces a promising methodology that enhances the quality of motion cueing, thus rendering flight simulations more realistic and beneficial for both pilots and aerospace engineering researchers in the real of non-maneuvering aircraft flight simulators

Improved Friction Reduction and Wear Resistance of Steel Using a Subnanometer Nanowires-Poly-α-Olefin Gel Lubricant.

Lubricating oil is commonly utilized due to its excellent lubricating properties in mechanical motion systems. However, high fluidity in lubricating oil often leads to leakage during machine operation, causing mechanical components to fail. Herein, a gel lubricant of SNWs-PAO6 was devised by combining subnanometer nanowires (SNWs) with poly α-olefin 6 (PAO6) at room temperature, effectively confining PAO6 and preventing PAO6's creeping and leakage while enhancing its load-bearing capacity. SNWs-PAO6 outperforms PAO6 in reducing friction and wear for steel-on-steel interfaces. The friction coefficient is markedly diminished by 57.53%, from 0.223 to 0.095, while the wear rate is significantly curtailed by 84.98%. Furthermore, SNWs-PAO6 remains stable even after 180 000 cycles at 200 N and 25 Hz, withstanding high-speed centrifugation without releasing PAO6. It remained stable over 6 months of resting and can well withstand low temperatures. Surface analysis of the wear scar and the formed tribochemical film after friction has demonstrated that PW12O403- is more likely to adsorb onto the steel surface, forming a lubricating medium film through tribochemical reactions and thus reducing interfacial friction and wear. This method facilitates the development of domain-limited nanomaterials-based gels for mass production and their applications in engineering moving parts.

Arm weight effects on dynamic walking stability in individuals with hemiparetic stroke.

This study examined the effects of arm weights on dynamic stability during overground walking in individuals with hemiparetic stroke. Arm weights have been shown to improve mobility in stroke survivors, potentially at the cost of decreased dynamic stability and increased fall risk. Data from nine stroke survivors (8 males, 1 female; age: 58.0 ± 6.8 years) were assessed under four conditions: no weight, weight attached to the non-hemiparetic side, weight attached to the hemiparetic side, and bilateral weights. Each condition used 0.45 kg sandbags. Kinematic data were captured using an eight-camera motion system and analyzed to assess center of mass position and velocity relative to the base of support. Although repeated measures ANOVA showed no significant differences in stability across conditions, individual scatter plots revealed variable responses among participants. Some maintained or improved their stability, while others experienced decreases under specific conditions. These findings underscore the need for personalized approaches in rehabilitation planning, suggesting that integrating arm weights into rehabilitation protocols may not compromise dynamic stability for most stroke survivors. Further research with larger sample sizes and varied weights is essential to validate these findings and tailor the use of arm weights in stroke rehabilitation more effectively.

A novel ultrasonic shot peening method for surface enhancement of fastener holes

Hole structures represent discontinuities in mechanical parts, and their inner walls need to be surface strengthened to enhance the service performance. In this study, a novel ultrasonic shot peening (USP) method, which is equipped with a wave-shaped horn and can be inserted into holes is developed to strengthen the fastener holes. Firstly, the axis uniformity of static and motional USP systems is compared in 304SS holes. After treated by static USP, the peening intensity along the hole axis is consistent with the wavy surface of the horn. The impact velocity and impact number of the balls driven by the trough of the horn are approximately four times and three times higher, respectively, compared to those driven by the peak structure. Thus the regions treated by the trough of the horn exhibit greater surface roughness (Ra = 0.97 μm), higher hardness (510 HV) and a deeper deformed layer (94.3 μm). While the motional system effectively improves the axis uniformity of the holes by diminishing the concentration of the stronger and weaker shot peening areas. For GH4169 holes treated by motional USP, a cold work layer with depths of 100–150 μm is formed; a plastic deformed layer exceeding 50 μm is observed and a residual compressive stress layer exceeding 200 μm is introduced. These results are consistent with those of plate or cylindrical samples treaded by USP. Moreover, the differences between USP and other techniques are subsequently discussed.

Effect of recording angle on accuracy of Kinovea-based kinematic gait analysis compared to three-dimensional motion analysis in healthy dogs: optimal at 90° recording angle

Abstract OBJECTIVE The goal of this study was to investigate the effect of recording angle on the accuracy of 2-D Kinovea-based kinematic motion analysis (KMA) compared to 3-D KMA in dogs. METHODS In this prospective study, 3-D marker-based KMA (VICON-Nexus, version 2.12.1, and Procalc, version 1.6; VICON Motion Systems Ltd) was performed on healthy dogs (body weight ≥ 20 kg) walking on a treadmill (study period: November 2022). Simultaneously, dogs were video-recorded by 3 smartphones (iPhone SE; Apple Inc) at 1.50 m distance and 45°, 90°, and 135° recording angles relative to the shoulder for Kinovea-based, angle-calibrated KMA. Shoulder, elbow, carpal, hip, stifle, and tarsal joint kinematics were calculated for 3 synchronized gait cycles. Each gait cycle was divided into 10 increments. The estimated difference between 3-D KMA and Kinovea was assessed using robust linear mixed-effects models. RESULTS 34 dogs were included. Differences of less than 5° between methods were considered reasonable. At a 45° recording angle, the estimated joint angle difference was < 5° for the carpus and hip during ≥ 5 of 10 gait cycle increments. At 90°, the difference was < 5° across all joints for ≥ 9 of 10 increments and at 135° was < 5° for the elbow, carpus, and hip for ≥ 7 of 10 increments. CONCLUSIONS Kinovea-based kinematics were most accurate when recorded at 90°. At 45°, Kinovea provided accurate data for the carpus and hip and at 135° for the elbow, carpus, and hip. CLINICAL RELEVANCE While angle-calibrated kinematic measurements can be accurate when using Kinovea for canine KMA, a 90° recording angle is preferable.

First motional stark effect measurements at Wendelstein 7-X

The rotational transform plays a crucial role in magnetic confinement devices and its profile is directly related to stability and confinement properties. A popular way to assess the rotational transform profile is using a Motional Stark Effect diagnostic system, which relies on the splitting of the Balmer alpha emission, due to the interaction between a particle beam and the plasma. A prototype diagnostic was installed at the stellarator Wendelstein 7-X, in order to demonstrate that such a diagnostic can be operated in this device. This work presents the diagnostic design and preliminary measurements as well as the calibration procedures necessary to deal with the extra complexity of measuring polarisation via an aluminium mirror. Qualitative agreement with simulations is shown in the variation of the measured polarisation angle over wavelength. A small but significant change in the measured angle is seen with changes in the plasma beta. While of a similar order to that expected, insufficient sensitivity of the prototype precludes a quantitative match to the prediction. The required changes to sufficiently improve the sensitivity to achieve this in future experiments is discussed.

Piezoceramic Actuation for Precision Enhancement in a Multistage Industrial Motion System

Piezoceramic Actuation for Precision Enhancement in a Multistage Industrial Motion System

Implementation of Control Valves System on Microturbine Drone’s Rotational Motion

The drone technology has received a wide range of research focusing on improving flight dynamics, battery life, payload capacity and sensor technology. However, for the applications of using drone for high rise buildings are limited by battery life for longer flight with longer duration tasks. This work presents the implementation of a control valve systems for the rotational motion of a microturbine drone. The first objective of this project was to design and develop a control valve system for a microturbine with propeller. The second objective was to measure micro turbine’s performance output which consisted of revolution per minute (rpm) and voltage (V) produced with the control valves system. The final objective was to verify the effectiveness of the control valve system by measuring the differences of the turbine speed of each turbine on the quadcopter to conceptually control the rotational motion of the drones. In conclusion, this work demonstrated the concept of the developed control valve system that can control the rotational motion of the drone.

Medial congruent with posterior cruciate ligament resected achieves similar short term outcome as posterior stabilised total knee arthroplasty.

Medial congruent (MC) systems and Posterior stabilized (PS) systems are widely utilized as implant options in total knee arthroplasties (TKAs). Nevertheless, determining which system yields superior clinical outcomes remains unresolved. This study seeks to compare these two systems by conducting a retrospective analysis of data from a single surgeon's registry encompassing both systems. Evaluation parameters consist of range of motion (ROM) and various clinical scoring systems. A retrospective analysis of data from a single surgeon's registry compared 45 MC with PCL resected (MC-PCLR) TKAs with 44 PS TKAs. Inclusion criteria comprised primary knee osteoarthritis with a minimum 1-year follow-up, while exclusion criteria involved secondary knee osteoarthritis and revision TKAs. Range of motion, Oxford Knee Score (OKS), Knee Society Scoring System (KS) Function Score (KS-FS), and KS Knee Score (KS-KS) were assessed preoperatively, at 3months, and at 12months postoperatively. Statistical analysis was performed on retrieved data. Both group has similar baseline demographics in terms of gender (68% vs. 73% female, p = 0.60), BMI (26.4 ± 5.7 vs. 28.3 ± 5.1 p = 0.81) and American Society for Anaesthesiology score (75% vs. 84% score of 2, p = 0.12), with the exception of age where the PS group is significantly greater (71 ± 8 vs. 66 ± 7years, p < 0.01). There was no significant difference in range of motion (ROM), Oxford Knee Score (OKS), Knee Society Scoring System (KS) Function Score (KS-FS) and KS Knee Score (KS-KS) for all time periods except for one time stamp where preoperatively, the preoperative KS Knee Score (KS-KS) was significantly lower in the PS group. However, when comparing the change between KS-KS of pre-operation and 3months post operation (44 ± 18 vs. 31 ± 18,p < 0.01), and pre-operation and 1year post operation (46 ± 16 vs. 34 ± 17,p < 0.01), it is found to be significantly higher in the PS group for both time periods. All other comparisons between the three time periods were found to have similar parameters. PS and MC-PCLR demonstrates similar outcomes at the 1-year mark. However PS exhibits a faster rate of improvement from pre-operation to 3months as compared to MC-PCLR.

A novel bionic parallel XY piezoelectric stick-slip positioning stage

This paper reports a novel parallel XY piezoelectric stick-slip positioning stage with bionic actuation mechanisms and driving strategies by mimicking fleas in nature. In particular, it exhibits low stress, macro-stroke decoupling, easy regulation, and smooth transition. Double-circular arc bionic flexible hinges are devised to reduce stress. Meanwhile, piezoelectric stick-slip driving is combined with orthogonal guiding mechanisms to realize high resolution, large stroke, and parallel decoupling. Also, a bionic driving strategy with improved Hopf oscillators is proposed to regulate stick-slip motion and decrease system disturbances. Statics and dynamics models are derived, and stress, frequency, and single-step displacement are simulated. Finally, a prototype is manufactured, and its performance is tested. The maximum velocity is 9.03 mm/s, x- and y-direction displacement coupling rates are 0.89 % and 0.92 %, resolutions are 5 nm and 5.5 nm, and maximum horizontal and vertical loads are 1.4 N and 40 N, respectively. Meanwhile, the positioning stage can quickly converge to its steady state even under a 30 V interference and suppress the micro/nano vibration using the proposed driving strategy. Experiments verify the effectiveness of the structural design and bionic driving strategy.

Motion System of a Four-Wheeled Robot Using a PID Controller Based on MPU and Rotary Encoder Sensors

Motion System of a Four-Wheeled Robot Using a PID Controller Based on MPU and Rotary Encoder Sensors

A radiation therapy platform to enable upright cone beam computed tomography and future upright treatment on existing photon therapy machines

AbstractBackgroundThe conventional lying down position for radiation therapy can be challenging for patients due to pain, swallowing or breathing issues. To provide an alternative upright treatment position for these patients, we have developed a portable rotating radiation therapy platform which integrates with conventional photon treatment machines. The device enables cone‐beam computed tomography (CBCT) imaging of patients in an upright position, and the future delivery of therapeutic radiation.PurposeTo design, manufacture, and test a device for upright radiation therapy. A collaborative partnership between physicists, engineers, radiation therapists, radiation oncologists, implementation researchers and consumers was established, to create a device that meets both the clinical and technical requirements of upright radiation therapy. The device is central to a clinical trial (ACTRN12623000498695) which will evaluate upright image quality in the context of future image guided radiation therapy for patients with lung cancer or head and neck cancer.MethodsThe weight and physical constraints of the device were assessed with respect to the American civilian population. The final design was evaluated with a series of tests to characterize the angular accuracy of the platform rotation and the reproducibility of the platform setup position in a radiation treatment room. To acquire an upright CBCT, the platform movement system was synchronized to the kilo‐voltage fluoroscopic imaging on an existing treatment machine. The accuracy of the synchronization was evaluated by assessing the positional reproducibility of upright CBCT imaging of a chest phantom.ResultsThe platform has a weight limit of up to 125 kg which is suitable for approximately 90% of males and 95% of females. The platform has physical constraints that accommodate approximately 95.6% of males and 99.6% of females: a maximum seated height of 97.5 cm, a maximum hip breadth of 63.0 cm, and maximum elbow to knuckle length of 46.5 cm. The angular accuracy of the motion system is within ±0.15° over a full rotation, which is within the guidelines for machine movement accuracy in radiation therapy (1 mm/1°). The platform is a portable device and can be reproducibly positioned in a radiation therapy treatment room with a translational range within ±0.04 mm and a rotational range within ±0.025°. The CBCT imaging can reproducibly detect the position of a chest phantom with a translational uncertainty of ±0.07 mm and a rotational uncertainly of ±0.22°, when imaging is acquired following a strict procedure.ConclusionThe upright radiation therapy platform is suitable for the evaluation of CBCT imaging in the context of image guided radiation therapy. The platform will allow the investigation of open questions in upright radiation therapy in the areas of patient experience, positional stability, anatomical changes, and treatment delivery. Improvements to the materials in the radiation beam line, synchronization with the existing treatment machine, and increasing the device weight limit are suggested prior to delivery of future upright treatments.

Development of a Shoelace Tensile Testing System and Investigation into the Effects of Different Running Speeds on Shoelace Tensile Variation

AbstractThis study investigated the validity and sensitivity of a custom-made shoelace tensile testing system. The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tightness levels during running. Mechanical tests were conducted using 16 weights, and various statistical analyses, including linear regression, Bland-Altman plots, coefficient of variation, and intraclass correlation coefficient, were performed to assess the system’s validity. Fifteen male amateur runners participated in the study, and three conditions (loose, comfortable, and tight) were measured during an upright stance. The system utilized VICON motion systems, a Kistler force plate, and a Photoelectric gate speed measurement system. Results showed a linear relationship between voltage and load at the three sensors (R2 ≥ 0.9997). Bland-Altman plots demonstrated 95% prediction intervals within ± 1.96SD from zero for all sensors. The average coefficient of variation for each sensor was less than 0.38%. Intraclass correlation coefficient values were larger than 0.999 (p&lt;0.0001) for each sensor. The peak tension of the front shoelace was greater than that of the front and middle when the shoelace was loose and tight. The rear shoelace had the highest tension force. The study also found that shoelace tension varied throughout the gait cycle during running. Overall, this research provides a novel and validated method for measuring shoelace tensile stress, which has implications for developing automatic shoelace fastening systems.

Optimasi Deteksi Gerak Bahasa Isyarat dan Ekpresi Wajah Real Time Dengan Metode Random Forest

Sign language is the primary means of communication for deaf individuals, one of the alternative languages used by people with disabilities, and it has evolved from the deaf community. Sign language has many variations, making it something unfamiliar and difficult to interpret for some hearing or uninitiated people. This research aims to develop a real-time sign language motion and facial expression detection system using the Random Forest method. The main challenge in this detection is the complexity and variation of the movements and facial expressions. In this study, MediaPipe is used to extract features from video input, which are then analyzed using the Random Forest algorithm for classification. In this research, the model's evaluation results use a confusion matrix with testing scenarios based on the division of training and testing data. From the model evaluation results, an accuracy of 99% was achieved. This research is expected to help deaf individuals communicate with hearing people, thereby reducing social gaps.

Computational fluid dynamics for naval hydrodynamics

This article describes key issues which have to be addressed to apply Computational Fluid Dynamics to Naval Hydrodynamics. The specific aspects of Naval Hydrodynamics are discussed and illustrated by recent simulations and comparisons with available experiments. Free-surface flows with or without waves and even violent phenomena such as ventilation or cavitation can be modelled with mixture-fluid surface capturing. Turbulence modelling of thick boundary layers and vortical flows requires anisotropic RANS models or hybrid RANS/LES in case of strongly separated flows. Moreover, fluid–structure interaction in the form of rigid or flexible body motion and multi-body systems is crucial to represent ship manoeuvring and propulsion. Finally, the paper underlines the central role played by anisotropic adaptive grid refinement in the accurate simulation of marine flows.

Integrating Problem-Based Learning Through Worksheet Development To Enhance Students' Critical Thinking Skills

The principle of problem based learning is to carry out investigations to find the truth by studying theories, asking experts, and also by conducting experiments depending on the problems found. Worksheet based on problem design emphasizes student activities to search for information through various sources such as environmental investigations, studies related to issues according to the content, formulating problems, comparing investigation results, proposing and considering the solutions obtained. The average value results for advisability of the product from the two validators are presentation of content 95%, discussion 85.6% and language 97.5% are very advisability category. Student responses to teaching modules was 100% of students’ students stated they were eligible. To find out of effect of worksheet based on problem, from the results of statistical tests using the paired sample t test using the SPSS 26 application, it can be concluded that there is a difference in the average student scores before and after implementing the worksheet based on problem. The students' critical thinking test results obtained a gain score of 49.4 with a high category of 58.8%; 41.2% low; and 0% low. The conclusion from this development research is that there is an influence of worksheet based on problem on motion systems content in learning and increasing students' critical thinking. The presence of worksheet based on problem helps the process of training students' higher-level thinking skills

CoupNeRF: Property‐aware Neural Radiance Fields for Multi‐Material Coupled Scenario Reconstruction

AbstractNeural Radiance Fields (NeRFs) have achieved significant recognition for their proficiency in scene reconstruction and rendering by utilizing neural networks to depict intricate volumetric environments. Despite considerable research dedicated to reconstructing physical scenes, rare works succeed in challenging scenarios involving dynamic, multi‐material objects. To alleviate, we introduce CoupNeRF, an efficient neural network architecture that is aware of multiple material properties. This architecture combines physically grounded continuum mechanics with NeRF, facilitating the identification of motion systems across a wide range of physical coupling scenarios. We first reconstruct specific‐material of objects within 3D physical fields to learn material parameters. Then, we develop a method to model the neighbouring particles, enhancing the learning process specifically in regions where material transitions occur. The effectiveness of CoupNeRF is demonstrated through extensive experiments, showcasing its proficiency in accurately coupling and identifying the behavior of complex physical scenes that span multiple physics domains.