Motion Characteristics Research Articles

Neuro-Fuzzy Logic for Automatic Animation Scene Generation in Movie Arts in Digital Media Technology

Animation scene generation (ASG) is the best digital media tool for lifelike scenes, particularly for movies. Traditional animation methods are laborious, computationally intensive, and scalable. Thus, this work addresses animation production issues using NFL-ASG. Combining fuzzy logic with a convolution neural network may create more realistic animated situations with less human interaction and better learning. Convolutional model training uses animation scenarios’ complicated motion patterns, character interactions, and ambient factors. Deep learning and fuzzy logic might change animation by boosting production techniques and releasing digital media technological creativity. After testing the system on the Moana Island scene dataset, it achieved a perception analysis success rate of 0.981% and a minimal processing complexity of (n logn).

Seismic Analysis of Irregular Building Subjected to Pounding

Earthquakes have always been a source of great devastation for humanity. With the fast growth of metropolitan cities, land limitation has become a critical issue, resulting in the construction of high-rise buildings very close to each other. Such buildings are prone to seismic pounding. During earthquake, the buildings vibrate out of phase and at rest separation is deficient to accommodate their relative motions. It can be prevented by ensuring safe separation distances between buildings. However, achieving the necessary separations is often not feasible in metropolitan areas due to high land values and limited land availability. Different combinations of 12-storey and 8-storey buildings with varying plan irregularities were considered for the analytical study using ETABS software. The pounding effect depends on building characteristics, ground motion characteristics and soil structure interaction. The parameters like displacement, impact force, and storey shear were determined.

Effects of ground motion characteristics on liquefaction response of earth dams using a non-Darcy hydro-mechanical model

During earthquake-induced excitations, significant pore pressure gradients can develop in earth dams, limiting the applicability of Darcy’s law for fluid flow. This study investigates the behavior of a liquefied earth dam subjected to various seismic excitations with differing frequency content, aiming to enhance insights into the effects of dynamic loading on fluid–structure interactions. To accurately capture the soil’s response, the Pastor-Zienkiewicz generalized plasticity model is employed to represent realistic soil behavior. Additionally, a modified Forchheimer equation is used to address varying permeability through a non-Darcy flow law. Numerical simulations, performed using a finite element code developed in Fortran, are validated through comparative analyses with previous studies. The results show that in low-permeability regions, changes in earthquake frequency content have minimal impact on discrepancies between the predicted results of Darcy and non-Darcy models. However, the non-Darcy model generally estimates horizontal displacements to be around 4% higher on average in these regions. This difference increases as earthquake frequency content decreases, reaching up to 6%. In contrast, in permeable regions, the non-Darcy model predicts significantly higher horizontal displacements, with an average increase of approximately 20% for high-frequency seismic events and 8% for low-frequency ones. Additionally, in high-permeability regions, the non-Darcy model deviates notably from the Darcy model as peak ground velocity increases, particularly affecting the upstream shell and clay core of the dam. This disparity becomes more pronounced as the input motion’s frequency content decreases, resulting in elevated pore pressures and slightly reduced vertical displacements in these regions.

A new approach for assessing the contribution of Ground Motions Frequency Content and Soil-Structure Interaction to the Seismic Response of Reinforced Concrete Moment Frames

One of the key steps in the seismic resilience assessment of buildings is gaining insight into their seismic response. The frequency content of ground motions and the dynamic characteristics of the building contribute mutually to the seismic response of the entire system (soil + structure). This study aims to present a new approach to assess the effects of the soil structure interaction (SSI) and of the frequency content of the ground motion. A case study of reinforced concrete moment frames (RCMFs) is herein presented by applying 280 ground motion time history records, which were registered on site classes A and B (based on ASCE 7–16). To this end, initially the characteristics of the input motions (e.g. amplitude and frequency content) were calculated, and then the time histories were partitioned into three clusters based on two optimal clustering features, namely Peak Ground Acceleration to Peak Ground Velocity ratio (PGA/PGV) and F5 (representing the frequency associated with 5% of total power in cumulative power spectral density, PSD). The clustering were done by implementing an unsupervised machine learning (ML) algorithm (i.e. K-means clustering), also the number of clusters was achieved using a well-known method in ML literature. Several time histories from each of the clusters were randomly selected to perform incremental dynamic analysis (IDA) on a 6- and a 10-story RCMF. Two different base conditions were considered: fixed-based (SSI neglected) and flexible-base (considering SSI effects). The findings demonstrate the contribution of frequency content and SSI to the seismic response of RCMFs, and also present an approach for considering frequency content in seismic analysis.

Investigating the Effect of Dilatancy Angle and Cohesion on Particle Motion Characteristics Using the SPH Method

Investigating the Effect of Dilatancy Angle and Cohesion on Particle Motion Characteristics Using the SPH Method

The influence of canard wing parameters on the vertical water entry of a vehicle

Flow control techniques are beneficial for changing the flow and motion characteristics of a vehicle during water entry. Combined with high-speed photography and inertial measurement unit, this paper investigated the cavity evolution and vehicle kinematics during water entry by varying the length, height, and width of a single canard wing. Research indicates that changing the wing length minimally affects the shape and size of fore-end cavity. For the attached cavity on the wing, increasing wing length promotes the formation of the cloudy flow characterized by violent air–water mixing, destroying the integrity of it. As wing height increases, the fore-end cavity profile approaches a rectangle, while the attached cavity on the wing evolves from an ellipse to a triangle. Increasing the wing width shifts the fore-end cavity profile from a rectangle to a trapezoid. There is an impact on the vehicle when the fore-end cavity occurs pinch-off. The impact peak rises with the increase in wing height and width, while the impact duration decreases. Changing wing length has little effect on peak value of pinch-off. Increasing the wing length and height reduces deflection of the vehicle, while increasing the wing width promotes the deflection of the trajectory and attitude.

Dynamic response of spring valve subjected to underwater pressure pulse

Spring-loaded valves are widely used to protect sealed containers filled with liquid against sudden excessive overpressure; however, the unstable vibration of a valve spool under dynamic loading may lead to safety incidents. This study aims to investigate the nonlinear vibration processes of a valve spool subjected to an underwater pressure pulse. To achieve this objective, the spring-loaded valve was simplified to an air-back mass spring with a constraint boundary (AMSCB). A modified split Hopkinson pressure bar (SHPB) was adopted to generate a controllable pressure pulse to establish the relationship between the specific impulse and the discharged water mass. Following the experimental verification, the influences of the pressure pulse parameters and dimensionless time on the motion characteristics of the mass block and flow rate were studied based on finite element (FE) simulations. Five motion modes were identified according to the number of collisions with the constraint boundary and changes in movement direction: (i) no collision, (ii) single collision, (iii) chatter, (iv) single collision with direction change, (v) multiple collisions. Moreover, a theoretical model for predicting the movement of a mass block was developed and validated against numerical results. The classification phase diagram of the motion mode is presented in a two-dimensional plane composed of specific strength coefficient ϕ and fluid-structure interaction coefficient ψ, and the influence of the geometrical parameters of the AMSCB on the classification boundary of motion modes is presented. The results indicate that, when subjected to underwater pressure pulse loading, the mass block repeatedly collides with the constraint boundary and undergoes non-periodic motion. With higher loading pressure amplitude and duration, the mass block is more likely to collide with the back boundary, leading to a transition in movement modes from mode (i), mode (ii), mode (iv) to mode (v). Increasing the stiffness coefficient and areal density will increase the threshold of ϕ and ψ for the transition from mode (i) to mode (v), while the maximum allowable displacement has little effect on the classification boundaries. These research findings are valuable for analysing the motion response of mass spring with various constraint boundaries under dynamic loading, and for guiding the design of spring-loaded valves.

Parametric classification based on kinematic characteristics of objects for identification of criminals

The problem of identifying objects in conditions of their disguise and impossibility of assessment by video images is studied. Potential criminals can be considered as such objects. The task is to assess whether the observed object is a potential criminal element or an ordinary person.It is proposed to use kinematic characteristics of human motion as factors-features for solving the recognition problem, in particular, components of the speed and acceleration vectors of characteristic points of the body in the system of generalized coordinates using Lame functions.It is proposed to use a parametric classification algorithm to solve the identification problem with such a choice of factors-features. The proposed idea, if practically implemented, can create conditions for detecting criminals or identifying suspicious persons for subsequent control checks

Motion characteristics of sphere with uniaxial through-hole after passing through air–water interface: Case study with different submergence depths

A vented sphere with a density of 2.6 × 103 kg/m3 and a diameter of 25.4 mm containing a circular uniaxial through-hole (diameter: 6 mm) was launched vertically upward from stationary water toward the air–water interface. The launch speed was adjusted such that the Reynolds number of the sphere was approximately 3000 immediately after it passed through the air–water interface. The effects of varying the submergence depth on the motion of the vented motion and behavior of the air–water interface were investigated. The entrained water mass increased with the submergence depth, resulting in an increase in the kinetic energy loss of the vented sphere. As the submergence depth increased, the vented sphere rotated as it passed through the air–water interface, and a sheet-like water mass was formed parallel to the direction of the through-hole. The vented sphere moved in the direction opposite to the scattering of the water mass. The vented sphere lost more kinetic energy compared to a normal sphere (without through-holes) while passing through the air–water interface at the same Reynolds number. These results indicated that the presence of the through-hole affected the motion characteristics of the sphere and behavior of the entrained water mass. These findings provide useful information for effectively controlling the attitude of artificial swimming devices that pass-through air–water interfaces.

Mathematical modeling and CFD investigation of the novel oscillating shear valve generating sinusoidal signals by fluid pressure fluctuation

The oscillating shear valve pulser is a critical component of advanced downhole high-speed transmission systems, playing a vital role in efficient drilling operations. It is highly valued for its flexible and accurate source signal modulation capabilities, as well as its ability to operate safely without blockages. Specifically, how to ensure that the oscillatory shear valve pulse generator produces high-quality sinusoidal differential pressure source signals is particularly crucial. Consequently, this paper initially considers the motion characteristics of the shear valve in acceleration-uniform speed-deceleration, derives the calculation formula of the throttle area of the valve hole based on the fan-arc-fillet-line, and adopts the latest unsteady-liquid thin-walled cutting-edge throttling mechanism (UTCTM) we discovered, innovatively proposing the mechanism model of the differential pressure signal generation of the oscillatory shear valve. Based on this model, a typical optimized four-blade oscillatory shear valve was obtained. Through a series of CFD computational fluid dynamics studies, the amplitude variation characteristics and sinusoidal morphology evolution laws of the differential pressure signal at different frequencies were revealed, forming a unique design method for oscillatory shear valves, which provides a solid theoretical basis and technical support for the development of a new generation of pulsers.

Ground motion characteristics of subshear and supershear ruptures in the presence of sediment layers

SUMMARY We investigate the impact of sediment layers on ground motion characteristics during subshear and supershear rupture growth. Our findings suggest that sediment layers may lead to local supershear propagation, affecting ground motion, especially in the fault parallel (FP) direction. In contrast to homogeneous material models, we find that in the presence of sediment layers, a larger fault normal (FN) compared to FP particle velocity jump, reflects shear propagation at depth but does not rule out shallow supershear propagation. Conversely, a large FP compared to FN particle velocity jump indicates supershear propagation at depth. In the presence of a shallow layer, we also uncover a non-monotonic behaviour in the sediment’s influence on supershear transition and ground motion characteristics. During supershear propagation at depth we observe that sediment layers contribute to enhancing FP velocity pulses while minimally affecting the FN component. Furthermore, in the limit of global supershear propagation we identify local supersonic propagation within the sediment layers that significantly alters the velocity field around the rupture tip as observed on the free surface, creating both dilatational and shear Mach cones. In all our models with sediments we also find a significant enhancement in the fault vertical component of ground velocity. This could have particular implications for hazard assessments, such as in applications related to linear infrastructure, or a higher propensity to tsunami wave generation. Our research unravels the importance of considering heterogeneous subsurface material distribution in our physical models as they can have drastic implications on earthquake source physics.

Research on stability of modular multi-legged robots with non-isomorphic configurations

Modular robots can be reconfigured and deformed into multiple non-isomorphic configurations. Different configurations of robots exhibit diverse motion and stability characteristics. Therefore, the stability of robots with different configurations is essential to improve their motion control robustness and expand their application range. In this article, a new reconfigurable modular multi-legged robot is designed. To analyze the stability of the various typical non-isomorphic configurations of modular robots, a hybrid discrimination method combining the static stability margin-force angle stability margin-stability cone is proposed. By conducting simulation experiments on the static minimum tilt angle of robots in tilt, pitched, and yawed terrains, as well as their combinations, and evaluating the performance index of tipping in the presence of external force interference, the effectiveness of the proposed method can be proved. Furthermore, the movement experiments of the robot in irregular terrain under the quadruped configuration and hexapod configuration were carried out, it is proven that the robot under different configurations can maintain the stability of the structure.

Fast moving table tennis ball tracking algorithm based on graph neural network

The key object tracking in sports video scenarios poses a pivotal challenge in the analysis of sports techniques and tactics. In table tennis, due to the small size and rapid motion of the ball, identifying and tracking the table tennis ball through video is a particularly arduous task, where the majority of existing detection and tracking algorithms struggle to meet the practical application requirements in real-world scenarios. To address this issue, this paper proposes a combined technical approach integrating detection and discrimination, tailored to the unique motion characteristics of table tennis. For the detector, we utilize and refine a common video differential detector. As for the discriminator, we introduce GMP (a Graph Max-message Pass Neural Network), which is designed specifically for tracking table tennis balls or similar objects. Furthermore, we enhance an existing dataset for table tennis tracking problems by enriching its scenarios. The results demonstrate that our proposed technical solution performs impressively on both the dataset and the intended real-world environments, showcasing the good scalability of our algorithms and models as well as their potential for application in other scenarios.

Dynamic Analysis of Soil-Structure Interaction in Earthquake-Prone Areas

This study used a thorough experimental method to examine the dynamic interaction between soil and structures in earthquake-prone locations. The study challenge concentrated on how different soil types and configurations influence the diversity of structural reactions under seismic loading conditions. The research utilized a mixed methods approach, which involved quantitatively analyzing soil parameters and assessing structure dynamics. The methods employed included the creation of scaled replicas depicting common architectural structures situated on various soil types, including sandy, clayey, and mixed compositions. We used high-precision sensors to record ground motion characteristics such as Acceleration, velocity, and Displacement. The data was then evaluated using statistical methods such as ANOVA and regression analysis. The results revealed substantial differences in the structural reaction based on the type of soil and the parameters of the structure. Structures built on sandy soils saw greater peak accelerations (up to 0.170 g) but smaller displacements. On the other hand, structures on clayey soils had moderate accelerations (up to 0.140 g) but had bigger inter-story drifts. The varied soil layers, ranging from 1.500 Hz to 1.780 Hz, influenced the natural frequencies of the buildings. The damping ratios ranged from 5.000% to 7.800%, indicating that structural damping effectively reduces seismic forces. The results emphasized the critical importance of the interaction between soil and structures in seismic design and the necessity for customized engineering solutions based on the individual soil conditions at the site. Suggested measures include improving methods for soil characterization, optimizing structural dynamics using cutting-edge dampening technologies, and upgrading seismic design codes to enhance the ability of structures to withstand earthquakes in places prone to seismic activity.

Microsensor-Internalized Fibers as Autonomously Controllable Soft Actuators.

Despite their strengths in flexibility and miniaturization, the stable operation of soft actuators under ever-changing environmental and biological conditions is hindered by the lack of applicable methods using internal sensors to detect unintentional stimuli. Here, the integration of a microscale driving source and sensors in a single fiber via thermal drawing is presented as a strategy to scalably produce autonomously responsive, feedback-controllable soft actuators. The regulation of the input electrothermal stimuli via a closed loop control system that is based on completely coupled internal sensory components enables multimodal actuation of fiber-based actuators, which is further demonstrated through preservation of actuating conditions, actuation of selected devices in their bundles, and modulation of motion characteristics. The approach to manufacturing autonomously controllable soft actuators can expand applications of soft actuators in kaleidoscopic biomedical and bioengineering fields for transportation, robotics, and prosthetics.

Three-dimensional kinematic analysis of the cervical spine following posterior atlantoaxial fusion under physiological loading: An in vivo study

BackgroundThis study aimed to analyze the three-dimensional cervical motion characteristics in patients who underwent posterior atlantoaxial fusion surgeries using cone beam computed tomography and 3D3D registration technology. MethodsThe study selected 20 patients who underwent posterior atlantoaxial fusion surgery and 20 healthy people as the control group. All subjects underwent cone beam computed tomography scans of the occipital and cervical spine in 7 different functional positions, then 3D3D registration of Occipital-C7 was performed at each functional position to calculate the motion characteristics of each segment. The ranges of motion of the entire cervical spine and each segment were obtained in each functional position. FindingsIn the experimental group, ranges of motion of C1-C7 in flexion-extension and left-right twisting were significantly lower compared to controls (41.9° ± 13.8° vs. 56.6° ± 11.6°, 29.3° ± 9.6° vs. 91.2° ± 13.7°, respectively, P < 0.05). In the occipital-atlas segment, range of motion in flexion-extension was significantly smaller in the experimental group than controls (10.7° ± 3.2° vs. 19.4° ± 4.2°, P < 0.001), but it was larger in twisting (5.3° ± 4.2° vs. 2.1° ± 1.8°, P < 0.05). The twisting range of motion of C2-C3 was 4.7° ± 2.0° in the experimental group and 3.1° ± 1.6° in the control group (P < 0.05). Additionally, the alteration in ranges of motion during flexion-extension was primarily characterized by less extension. InterpretationThe posterior atlantoaxial fusion surgery induced biomechanical changes in the cervical spine. Following the procedure, the movement of C1-C7 during flexion-extension and twisting was significantly lower, with varying degrees of impact on adjacent and lower cervical segments. Moreover, the surgery had a greater effect on cervical extension than flexion.

Experimental study on the motion characteristics of non-spherical biomass particulate systems in a fluidization tube

This study experimentally investigated the transport characteristics of flaky, fibrous and streaky biomass particles in a fluidization tube. The movement and distribution of these non-spherical biomass particles in different sections of the fluidization tube were visualized and analyzed by using a Particle Tracking Velocimetry measuring approach. The method for calculating the solidity rate distribution of particles in the fluidization tube was also developed. Furthermore, the distribution patterns of non-spherical biomass particles with three different morphologies in the near-wall region of the fluidization tube were significantly analyzed. It could be observed that the area of the non-spherical biomass particles in the near-wall region exhibited an ’M’ shape. Three empirical formulas for predicting the maximum area of non-spherical biomass particle clusters in the fluidization tube were firstly proposed. Among the three prediction formulas, the correlation coefficients are 0.7142, 0.8797, and 0.9567, respectively.

Laboratory Assessment of Manual Wheelchair Propulsion

Self-propelled manual wheelchairs offer several advantages over electric wheelchairs, including promoting physical activity and requiring less maintenance due to their simple design. While theoretical analyses provide valuable insights, laboratory testing remains the most reliable method for evaluating and improving the efficiency of manual wheelchair drives. This article reviews and analyzes the laboratory methods for assessing the efficiency of wheelchair propulsion documented in the scientific literature: (1) A wheelchair dynamometer that replicates real-world driving scenarios, quantifies the wheelchair’s motion characteristics, and evaluates the physical exertion required for propulsion. (2) Simultaneous measurements of body position, motion, and upper limb EMG data to analyze biomechanics. (3) A method for determining the wheelchair’s trajectory based on data from the dynamometer. (4) Measurements of the dynamic center of mass (COM) of the human–wheelchair system to assess stability and efficiency; and (5) data analysis techniques for parameterizing large datasets and determining the COM. The key takeaways include the following: (1) manual wheelchairs offer benefits over electric ones but require customization to suit individual user biomechanics; (2) the necessity of laboratory-based ergometer testing for optimizing propulsion efficiency and safety; (3) the feasibility of replicating real-world driving scenarios in laboratory settings; and (4) the importance of efficient data analysis techniques for interpreting biomechanical studies.

Analysis and Experimentation on the Motion Characteristics of a Dragon Fruit Picking Robot Manipulator

Due to the complex growth positions of dragon fruit and the difficulty in robotic picking, this paper proposes a six degrees of freedom dragon fruit picking robot and investigates the manipulator’s motion characteristics to address the adaptive motion issues of the picking manipulator. Based on the agronomic characteristics of dragon fruit cultivation, the structural design of the robot and the dimensions of its manipulator were determined. A kinematic model of the dragon fruit picking robot based on screw theory was established, and the workspace of the manipulator was analyzed using the Monte Carlo method. Furthermore, a dynamic model of the manipulator based on the Kane equation was constructed. Performance experiments under trajectory and non-trajectory planning showed that trajectory planning significantly reduced power consumption and peak torque. Specifically, Joint 3’s power consumption decreased by 62.28%, and during the picking, placing, and resetting stages, the peak torque of Joint 4 under trajectory planning was 10.14 N·m, 12.57 N·m, and 16.85 N·m, respectively, compared to 12.31 N·m, 15.69 N·m, and 22.13 N·m under non-trajectory planning. This indicated that the manipulator operates with less impact and smoother motion under trajectory planning. Comparing the dynamic model simulation and actual testing, the maximum absolute error in the joint torques was −2.76 N·m, verifying the correctness of the dynamic equations. Through field picking experiments, it was verified that the machine’s picking success rate was 66.25%, with an average picking time of 42.4 s per dragon fruit. The manipulator operated smoothly during each picking process. In the study, the dragon fruit picking manipulator exhibited good stability, providing the theoretical foundation and technical support for intelligent dragon fruit picking.

Investigation into the rockfall impact process of a quarry landfill slope under highway expansion

AbstractA quarry landfill slope is commonly partially or entirely filled with quarry waste. On the surface, a substantial amount of rough stone waste accumulates. This study specifically investigated the hazards posed by individual rockfalls and cluster rockfalls induced by landslides in such slopes, using an engineering slope as an illustrative example. The discontinuous deformation and displacement analysis method was employed to analyze the individual and cluster rockfall motion characteristics, as well as the dynamic response of protection structures. The results indicate that: (1) The impact of individual falling rocks on structures results in deformation and damage that far surpasses that caused by a flat plane impact. Interestingly, the stress generated upon rockfall contact with the structure is not initially at its maximum; it gradually increases to a peak as deformation occurs. When the structure is damaged or rebounds, the impact stress significantly diminishes. For wedge-shaped falling rocks impacting the upper part of the structure, bending tilting failure tends to occur. Conversely, irregular blocks with larger volumes impacting the lower part of the structure often lead to direct toppling failure; (2) Clusters falling rocks impede the movement of the sliding body. As the front and rear sliding bodies fracture along the middle, the rear sliding body tilts. Consequently, accumulated blocks are struck by the sliding body, initiating oblique throwing movements. There is a high likelihood of these rocks crossing protective structures; (3) The protection rate of the protective structure against single block stone impact stands at 86.7%. However, when subjected to the impact of a group of rockfalls, the protective structure completely fails. Overall, although the current protective measures are relatively cost-effective, the extremely high probability of casualties makes them unacceptable.