Body Acceleration Research Articles

Advanced active suspension control: A three-input fuzzy logic approach with jerk feedback for enhanced performance and robustness

Active suspension systems aim to increase ride comfort by reducing body acceleration due to road disturbances. This research proposes a new fuzzy logic controller (FLC) for such systems which includes acceleration error as third input. The objective of the proposed 3-inputs FLC is to improve vehicle comfort and ensure passenger safety. To assess the performances of the newly introduced controller, a theorical study is conducted on a quarter-car system with a four-wheel independent suspension design. Simulation results demonstrate high performances of the proposed 3-inputs FLC compared with conventional PID and 2-inputs FLC. The acceleration error as an additional FLC input was, to the best of our knowledge, not explored yet. Hence, this contribution offers a new method for the design of more effective active suspension systems.

Pulsatile flow of EMHD non-Newtonian nano-blood through an inclined tapered porous artery with combination of stenosis and aneurysm under body acceleration and slip effects

Research on blood flow in diseased arteries has become a priority in recent years. Stenosis/aneurysm is the most common arterial diseases. This work investigates the mixed effect of electric and magnetic fields on the unsteady, two-dimensional, laminar, non-Newtonian pulsatile flow of blood in an axisymmetrically inclined tapered porous artery with stenosis and aneurysm containing gold nanoparticles, subjected to body acceleration and slip effect. Thermal radiation and heat sources are also included. To immobilize the effect of the vessel wall, we use a radial coordinate transformation. The nonlinear partial differential equations governing the present problem, together with the prescribed boundary conditions, are solved using an explicit finite-difference scheme. The current analysis could help to understand the improvement in mass distribution and heat transfer in diseased blood vessels, which might be useful for drug delivery in the therapy of stenosis and aneurysm.

LQR-Based Suspension for Heavy Vehicles Considering the Time-Varying Characteristics of Vehicle–Road Interaction

The rapidly increasing demand for heavy vehicles in the transportation sector has led to more severe road damage and significantly higher road maintenance costs. Investigation of active suspension system incorporating vehicle–road interaction (VRI) can provide effective means to reduce the road damage and improve the ride comfort of vehicles. In this paper, an active vehicle suspension controller based on the strongly stable and robust linear–quadratic regulator (LQR) principle is developed for the time-varying VRI system. The coupled system is modeled by a quarter-car traveling on the road modeled by an Euler–Bernoulli beam resting on a viscoelastic foundation. Two types of road irregularities, deterministic sine wave and random, are considered in the numerical studies. A time-frozen technique, by which the linear time-varying system is converted to a time sequence of time-invariant systems, is applied to solve for the coupled responses. Three variables, the dynamic tire load, vehicle body acceleration, and suspension relative displacement, are used to assess the effectiveness of the LQR-based controller in comparison to the passive suspension system. The performance of the active control is investigated for different vehicle speeds, vehicle loads, and road profiles. Numerical studies show that the controller can effectively reduce the road damage and improve the ride comfort, with a slight increase in the suspension relative displacement. This work lays a useful foundation in the problem formulation and system parameter influences for future vehicle suspension design and road damage mitigation including VRI.

Online optimal tuning of fuzzy PID controller using grey wolf optimizer for quarter car semi-active suspension system

In order to reduce vibration and increase ride comfort, this article utilizes a system of quarter-car suspension integrated with a Fuzzy PID controller. To build and improve the Fuzzy PID controller for the semi-active suspension system used in quarter cars, using a novel meta-heuristic technique known as Grey Wolf Optimizer (GWO). Here the magnetorheological damper (MR) fluid with the Fuzzy PID controller was examined to optimize using the GWO algorithm. With the GWO technique and the integral of time absolute error (IAE) as a fitness function, the three gain parameters of the Fuzzy PID controller – Kp, Ki, and Kd– have been optimally set. The suggested approach has additional advantages for the optimization of functions with three variables, including simplicity in implementation, quick convergence traits, and superior computational capabilities. This work is significant, to the best of the author’s knowledge there is no optimization method using GWO to online tune a Fuzzy PID controller for a semi-active suspension system. The optimal output parameters of the controller can be updated online in real-time by GWO. The performance of the proposed controller was examined by assessing the root mean square (RMS) values and peak-to-peak (PTP) values of body displacement and body acceleration under various road profiles. To ensure that the intelligent controller was of the highest caliber, an online test rig was constructed. Results from simulations and online experiments demonstrated that the Fuzzy GWO PID controller significantly improved ride comfort under a variety of road conditions when compared to the Fuzzy PID controller and passive suspension system.

Effects of Different Wearable Resistance Placements on Running Stability.

Stability during running has been recognized as a crucial factor contributing to running performance. This study aimed to investigate the effects of wearable equipment containing external loads on different body parts on running stability. Fifteen recreational male runners (20.27 ± 1.23 years, age range 19-22 years) participated in five treadmill running conditions, including running without loads and running with loads equivalent to 10% of individual body weight placed on four different body positions: forearms, lower legs, trunk, and a combination of all three (forearms, lower legs, and trunk). A tri-axial accelerometer-based smartphone sensor was attached to the participants' lumbar spine (L5) to record body accelerations. The largest Lyapunov exponent (LyE) was applied to individual acceleration data as a measure of local dynamic stability, where higher LyE values suggest lower stability. The effects of load distribution appear in the mediolateral (ML) direction. Specifically, running with loads on the lower legs resulted in a lower LyE_ML value compared to running without loads (p = 0.001) and running with loads on the forearms (p < 0.001), trunk (p = 0.001), and combined segments (p = 0.005). These findings suggest that running with loads on the lower legs enhances side-to-side local dynamic stability, providing valuable insights for training.

Modelling and simulation of suspension system based on topological structure

The traditional approach of longitudinal cutting in suspension system simplification introduces redundant degrees of freedom, leading to increased system errors. This study focused on a seven degrees of freedom (7DOF) car model and constructed a suspension system topology model based on an across-cutting approach. To emulate road surface excitation, the filtered white noise method was employed. MATLAB/Simulink was used to create simulation models for the across-cutting, traditional longitudinal cutting and the whole car structure. Comparative analysis of these three topologies was conducted in both the time and frequency domains. Simulation results demonstrated that the performance curve of the across-cutting simplified suspension system closely matched that of the whole car model, validating the accuracy of the proposed across-cutting topology. Furthermore, when compared to traditional longitudinal cutting, the across-cutting simplification method reduced the natural frequency error of body pitch vibration by 25% and decreased the root mean square error of body acceleration by 27%. The suspension topology based on across-cutting more closely resembled the actual car structure, offering a theoretical foundation for enhancing overall ride comfort in automobiles.

Optimizing Hydro-Pneumatic Inerter Suspension for Improved Ride Comfort and Handling Stability in Engineering Vehicles Using Simulated Annealing Algorithm

This study introduces a novel hydro-pneumatic inerter suspension (HPIS) system for engineering vehicles, aiming at enhancing ride comfort and handling stability. The research focuses on addressing the limitations of conventional suspension systems by incorporating an inerter element into the vehicle suspension. The unique aspects of HPIS, such as nonlinear stiffness and nonlinear damping characteristics of the hydro-pneumatic spring, are explored. Firstly, a half-car dynamic model of the HPIS suspension is established, and an improved simulated annealing algorithm is applied to optimize the suspension parameters. Then, we compare the dynamic performance of different HPIS structures, specifically parallel and series layouts. For practical analysis, a simplified three-element HPIS suspension model is used, and the suspension parameters are optimized by a simulated annealing algorithm at speeds of 10 m/s, 15 m/s, and 20 m/s. Key findings reveal that compared to the traditional suspension system of S0, the front and rear suspension working space of S1 decreased by 40%, 40.1%, 40.2% and 30.7%, 30.8%, 30.9%, while with the body acceleration and pitch acceleration deteriorated by 3.1%, 3.2%, 3.3% and 63.4%, 63.8%, 64.0%. However, the S2 can improve all the dynamic performance and offer better ride comfort and handling stability.

Disturbance observer-based sliding mode control of active vertical suspension for high-speed rail vehicles

Disturbance observer-based sliding mode control (SMC) on the active vertical suspension (AVS) is developed to suppress the car body’s rigid and flexible vibration to improve ride comfort for a high-speed rail vehicle. A vertical-dynamics-intended vehicle model is foremost built with the bounce, pitch, and bending mode of the car body involved. Two sliding surfaces and disturbance observers are then designed for SMC, which only require the car body states, obviating the bogies’ states. The observer is successful in estimating the effect of unknown track irregularities perturbation as well as externally straightforwardly excitations on the car body with good accuracy. Control efficacy is verified through comparison with passive cases and sky-hook controls. With modal damping below 2% in passive cases, the mode shape function, especially with large displacement at the suspension support, would enlarge the car body acceleration. Moreover, the longitudinal traction rod can significantly multiply the flexible vibration at certain speeds. Comparative studies indicate that SMC provides satisfactory outcomes in the rigid and bending vibration suppression when all the car body’s three modes are considered in the sliding surface. However, it requires a high-frequency response actuator and allows a tighter tolerance of the control time delay than the sky-hook control.

Diagnosis of disease affecting gait with a body acceleration-based model using reflected marker data for training and a wearable accelerometer for implementation

This paper demonstrates the value of a framework for processing data on body acceleration as a uniquely valuable tool for diagnosing diseases that affect gait early. As a case study, we used this model to identify individuals with peripheral artery disease (PAD) and distinguish them from those without PAD. The framework uses acceleration data extracted from anatomical reflective markers placed in different body locations to train the diagnostic models and a wearable accelerometer carried at the waist for validation. Reflective marker data have been used for decades in studies evaluating and monitoring human gait. They are widely available for many body parts but are obtained in specialized laboratories. On the other hand, wearable accelerometers enable diagnostics outside lab conditions. Models trained by raw marker data at the sacrum achieve an accuracy of 92% in distinguishing PAD patients from non-PAD controls. This accuracy drops to 28% when data from a wearable accelerometer at the waist validate the model. This model was enhanced by using features extracted from the acceleration rather than the raw acceleration, with the marker model accuracy only dropping from 86 to 60% when validated by the wearable accelerometer data.

Influence of environment-induced bridge vibration on high-speed train’s driving performance

When railways traverse densely populated industrial areas, the periodic operation of large-scale factory equipment can produce consistent and regular environmental excitation on bridge structures. This excitation, if resonant with the structure, may cause significant vibration of the bridge, posing a threat to trains’ running safety. For the first time, this paper tackles this practical concern by combining field measurements with an analysis of how environment-induced bridge vibrations impact the operational performance of high-speed trains. The environmental vibration was equivalently incorporated into the analysis of the train-bridge coupled vibration system, examining the effects of structural vibration amplitude, frequency, and environmental influence range. The effect of bridge vibration on the driving performance of high-speed trains was evaluated from the spatial frequency domain properties of dynamic irregularity of track and the trains’ performance sensitivity to different parameters. The field measurements reveal that the environment-induced bridge vibration results in a translational motion of the beam driven by the transverse bending of the pier, resonating at approximately 1.5 Hz with an amplitude of 1.33 mm. The CRH series train, characterized by a prominent lateral mode close to 1.5 Hz (i.e., the wavelength sensitive to the train’s lateral running stability predominantly falls within the 30 m–100 m range at speed of 200∼350 km/h), exhibits a high susceptibility to vibrations induced by the environment in bridges. Among the examined parameters, the amplitude of bridge vibration has the most pronounced impact on the train’s acceleration, showing a linear correlation. The combined effect of bridge vibration and track static irregularity resulted in the lateral acceleration of the car body reaching 0.9 m/s2, which is close to the regulatory limit of 1.0 m/s2. Through parameter analysis, the maximum amplitude of the bridge that can be sustained while ensuring driving stability can be determined.

Transition of Human Heart Rate Variability and Body Acceleration during the COVID-19 Pandemic Observed from Holter Electrocardiogram Big Data

Transition of Human Heart Rate Variability and Body Acceleration during the COVID-19 Pandemic Observed from Holter Electrocardiogram Big Data

Performance analysis of fuzzy-LQR and fuzzy-LQG controllers for active vehicle suspension systems

Suspension systems in vehicles are crucial to both ride quality and driving security. The challenge of creating an effective control mechanism for automotive active suspension systems is addressed in this work. In the event of unforeseen road disturbances, the active suspension systems are intended to deliver a more pleasant ride and good handling. Fuzzy-Linear Quadratic Gaussian (FLQG) and Fuzzy-Linear Quadratic Regulator (FLQR) controllers adapting to road disturbances are proposed to enhance vehicle comfort through the reduction of the driver's overall body acceleration. The simulation findings demonstrate that the FLQR and FLQG controllers are efficient in adjusting the automotive suspension configuration under varying road profiles compared to those of the conventional LQR and LQG controllers.

Impact of Annotation Modality on Label Quality and Model Performance in the Automatic Assessment of Laughter In-the-Wild

Although laughter is known to be a multimodal signal, it is primarily annotated from audio. It is unclear how laughter labels may differ when annotated from modalities like video, which capture body movements and are relevant in in-the-wild studies. In this work we ask whether annotations of laughter are congruent across modalities, and compare the effect that labeling modality has on machine learning model performance. We compare annotations and models for laughter detection, intensity estimation, and segmentation, using a challenging in-the-wild conversational dataset with a variety of camera angles, noise conditions and voices. Our study with 48 annotators revealed evidence for incongruity in the perception of laughter and its intensity between modalities, mainly due to lower recall in the video condition. Our machine learning experiments compared the performance of modern unimodal and multi-modal models for different combinations of input modalities, training, and testing label modalities. In addition to the same input modalities rated by annotators (audio and video), we trained models with body acceleration inputs, robust to cross-contamination, occlusion and perspective differences. Our results show that performance of models with body movement inputs does not suffer when trained with video-acquired labels, despite their lower inter-rater agreement.

Topology Optimization Design and Dynamic Performance Analysis of Inerter-Spring-Damper Suspension Based on Power-Driven-Damper Control Strategy

In this paper, the problem of broadband vibration suppression of power-driven-damper vehicle “inerter-spring-damper” (ISD) suspension is studied. The suspension can effectively inherit the low-frequency vibration suppression effect of ISD suspension and the high-frequency vibration suppression effect of the power-driven-damper control strategy. Based on the structural method, this paper proposes four suspensions with different structures. The optimal structure and parameters are obtained by using pigeon-inspired optimization. The results show that, based on the optimal structure, the Root-Mean-Square (RMS) of body acceleration and the RMS of suspension working space are reduced by 23.1% and 6.6%, respectively, compared to the traditional passive suspension. The influence of the damping coefficient on the dynamic performance of the power-driven-damper vehicle ISD suspension is further studied. The vibration suppression characteristics of the proposed suspension are simulated and analyzed in both the time domain and frequency domain. It is shown that the power-driven-damper vehicle ISD suspension can effectively reduce vibrations across a wide frequency range and significantly improve body acceleration and suspension working space, thereby enhancing the ride comfort.

APPLICATION OF THE VIBROPNEUMATIC SEPARATOR IN THE CLEANING AND PREPARATION SECTION OF THE CEREALS PROCESSING COMPANY

The development and introduction in the milling industry of new vibrating machines for separating and drying solid particles contributes to the intensification of this difficult technological process. The vibration action allows considerably improving the kinematic parameters – increasing the acceleration and frequency of the working body, reducing the amplitude of the oscillation of the working body compared to existing machines. Cleaning the batch of grains from impurities, sorting their derived products, as well as partially reducing humidity, represent the set of operations, which are carried out with the aim of increasing the quality of the grains in the batch and the derived products. Simultaneously with the removal of impurities, cleaning reduces the volume of products that must be handled, transported and stored, as well as the removal of 1-2% of moisture along the way. In the case of wheat intended for consumption, it is aimed to eliminate impurities as much as possible, which have no food value. The modernized vibropneumatic separator intended for the processing of cereal products, contains a body, mounted on a drum, with a hermetically fixed cover, in which a telescopic connection is placed for cutting the wet product. A working organ is located inside the body, made in the form of a conical sieve with the tip up. The conical sieve is rigidly connected with a vibrating mechanism, and with the bat - by means of elastic elements. Under the action of the vibrating mechanism, the working organ performs a complex spatial movement. Ducts for exhausting the air flow are installed on the circumference of the cover. An inner cone and an outer cone are placed one inside the other under the conical sieve. The device also contains connections for the discharge of the sifted fractions and refuse.

Determining energy expenditure in a large seabird using accelerometry.

The trade off between energy gained and expended is the foundation of understanding how, why and when animals perform any activity. Based on the concept that animal movements have an energetic cost, accelerometry is increasingly being used to estimate energy expenditure. However, validation of accelerometry as an accurate proxy for field metabolic rate in free-ranging species is limited. In the present study, Australasian gannets (Morus serrator) from the Pope's Eye colony (38°16'42″S 144°41'48″E), south-eastern Australia, were equipped with GPS and tri-axial accelerometers and dosed with doubly labelled water (DLW) to measure energy expenditure during normal behaviour for 3-5 days. The correlation between daily energy expenditure from the DLW and vectorial dynamic body acceleration (VeDBA) was high for both a simple correlation and activity-specific approaches (R2=0.75 and 0.80, respectively). Varying degrees of success were observed for estimating at-sea metabolic rate from accelerometry when removing time on land using published energy expenditure constants (R2=0.02) or activity-specific approaches (R2=0.42). The predictive capacity of energy expenditure models for total and at-sea periods was improved by the addition of total distance travelled and proportion of the sampling period spent at sea during the night, respectively (R2=0.61-0.82). These results indicate that accelerometry can be used to estimate daily energy expenditure in free-ranging gannets and its accuracy may depend on the inclusion of movement parameters not detected by accelerometry.

Entropy generation in the ternary nanofluid flow through an atherosclerotic vessel under periodic body acceleration

This article delves into the examination of the entropy generation within the slip flow of a ternary nanofluid flowing through a stenotic blood vessel. To capture the non-Newtonian rheology of blood, the constitutive equation of the Sutterby fluid model is employed. The governing equations are modeled in cylindrical polar coordinates. These equations are made dimensionless by a suitable choice of dimensionless parameters. Additionally, the dimensionless governing equations are simplified by applying the mild stenosis assumption. With the help of prescribed initial and boundary conditions, the numerical solution of the formulated problem is acquired by applying the explicit finite difference scheme. The outcomes of numerous governing parameters on the velocity profile, temperature profile, and entropy generation are explored through graphical forms. The velocity profile rises as the slip parameter and the inclination parameter are increased. The temperature profile rises with the growing values of the source parameter and decreases with enhancing values of the shape size parameter. The increasing strength of the applied magnetic field causes a reduction in the entropy generation. A comparison of the current study with the existing results is also presented. The plot of the Nusselt number shows that the height of stenosis plays an important role in monitoring its temporal variation. The current findings have been refined to provide elasticity-worthy material for researchers in the field of biomedical science who are interested in assessing blood flow under stenosis conditions and developing effective therapies for a wide range of diseases.

Electromagnetohydrodynamics Casson pulsatile nanofluid flow through a bifurcated stenosed artery: Magnetically targeted drug delivery

The current study is centered on the application of magnetically targeted drug delivery in a constricted vertical bifurcated artery utilizing Fe3O4 nanoparticles. The arterial stenosis is characterized by a bell-shaped narrowing in the parent artery and overlapping narrowing in the daughter artery. The blood is regarded as exhibiting the rheological behavior of a Casson fluid. The temperature-dependent nature of blood viscosity is postulated, and Reynold’s viscosity model describes it. This study examines the impact of electromagnetohydrodynamics (EMHD), body acceleration, Joule heating, and viscous dissipation. The assumption of a no-slip velocity condition is made at the walls of the artery. The governing equations are subjected to a process of non-dimensionalization and simplification, employing the mild-stenosis approximation. The resulting equations are subsequently solved in MATLAB by employing the finite-difference Crank–Nicolson technique. Entropy plays a significant role during any treatment or surgery; therefore, the present problem addresses entropy generation minimization. The results for velocity, temperature, wall shear stress, flow rate, impedance, heat transfer rate, entropy generation number, and Bejan number are represented graphically. The velocity contours illustrate that the flow velocity enhances with the Casson fluid and particle mass parameters. Furthermore, the number of trapped bolus also increases in the daughter artery. The nanofluid velocity and particle velocity decrease with an increase in the particle concentration parameter in the parent artery and the daughter artery. Entropy declines with the temperature difference parameter increment, whereas the Bejan number enhances. Magnetite (Fe3O4) nanoparticles have various applications owing to their biocompatibility, elevated magnetic susceptibility, chemical stability, non-toxic nature, and cost-effectiveness.

Effect of Inter-Vehicle Suspension on Variable Speed Curve Running of Train under Crosswinds

High-speed trains operating in windy areas may accelerate and decelerate frequently to maintain safe travel, especially when passing curves. During acceleration and deceleration, the role of inter-vehicle suspension (IVS) cannot be ignored. The present study aims to evaluate the effect of IVS on the variable speed curve running of trains under crosswinds. To achieve this purpose, a multibody model of a China Railways High-speed 2 (CRH2) high-speed train considering the IVS is established. By inputting the crosswind loads and traction or braking forces to the model and setting curved tracks with different radii and the unloading factor set as safety criterion, the safe running speeds of the train under different crosswind speeds and different track radii were obtained. The difference in the vehicle dynamics considering the IVS and the fixed connection under traction and braking conditions is analyzed. The radius of the curve track significantly affects the safety characteristics of a train under crosswinds, but its impact diminishes for radii greater than 7000 m. The lateral acceleration, movement angle, unloading factor, and derailment coefficient in both acceleration and deceleration cases of car bodies are affected by the IVS. As a consequence, the IVS will lead to lower safe speeds than fixed connections, but it will also convey more realistic and credible train dynamics.

MHD blood flow effects of Casson fluid with Caputo-Fabrizio fractional derivatives through an inclined blood vessels with thermal radiation

This study investigates a fractional-order time derivative model of non-Newtonian magnetic blood flow in the presence of thermal radiation and body acceleration through an inclined artery. The blood flow is formulated using the Casson fluid model under the control of a uniformly distributed magnetic field and an oscillating pressure gradient. Caputo-Fabrizio's fractional derivative mathematical model was used, along with Laplace transform and the finite Hankel transform technique. Analytical expressions were obtained for the velocity of blood flow, magnetic particle distribution, and temperature profile. These distributions are presented graphically using Mathcad software. The results show that the velocity increases with the time, Reynolds number and Casson fluid parameters, and diminishes when Hartmann number increases. Moreover, fractional parameters, radiation values, and metabolic heat source play an essential role in controlling the blood temperature. More precisely, these results are beneficial for the diagnosis and treatment of certain medical issues.