Longitudinal Movement Research Articles

Open Source, Open Science: Development of OpenLESS as the Automated Landing Error Scoring System.

The Open Landing Error Scoring System (OpenLESS) is a novel development aimed at automating the LESS for assessment of lower extremity movement quality during a jump-landing task. With increasing utilization of clinical measures to monitor outcomes and limited time during clinical visits for a lengthy analysis of functional movement, there is a pressing need to extend automation efforts. Addressing these issues, OpenLESS is an open-source tool that utilizes a freely available markerless motion capture system to automate the LESS using three-dimensional kinematics. To describe the development of OpenLESS, examine the validity against expert rater LESS scores in healthy and clinically relevant cohorts, and assess the intersession reliability collected across four time points in an athlete cohort. Observational. 92 participants (72 females and 20 males, mean age 23.3 years) from healthy, post-anterior cruciate ligament reconstruction (ACLR; median 33 months since surgery), and amateur athlete cohorts. A software package, "OpenLESS," was developed to interpret movement quality (LESS score) from kinematics captured from markerless motion capture. Validity and reliability were assessed with intraclass correlation coefficients (ICC), standard error of measure (SEM), and minimal detectable change (MDC). OpenLESS agreed well with expert rater LESS scores for healthy (ICC 2, k =0.79) and clinically relevant, post-ACLR cohorts (ICC 2, k =0.88). The automated OpenLESS system reduced scoring time, processing all 159 trials in under 15 minutes compared to the 18.5 hours (7 minutes per trial) required for manual expert rater scoring. When tested outside laboratory conditions, OpenLESS showed excellent reliability across repeated sessions (ICC 2, k >0.89), with a SEM of 0.98 errors and MDC of 2.72 errors. OpenLESS shows promise as an efficient, automated tool for clinically assessing jump-landing quality, with good validity versus experts in healthy and post-ACLR populations, and excellent field reliability, addressing the need for objective movement analysis. OpenLESS accurately detected jump-landing events (ICC>0.99) using markerless motion capture, validating its use as an alternative to laboratory-based force plate measurements.The automated scoring system showed good agreement with expert raters in healthy (ICC=0.79) and post-ACLR (ICC=0.88) populations.OpenLESS demonstrated good to excellent test-retest reliability (ICC=0.89) across multiple testing sessions, with minimal score variation, supporting its utility for longitudinal movement assessment.

Interferential Current Stimulation of Rectal Motor Activity - Objective Data from the Isolated Perfused Porcine Rectum.

Interferential Current (IFC) has been studied in several clinical trials for the treatment of bowel motility disorders, most often in children. However, only moderate effects are reported and in contrast to IFC, the so-called placebo application is indiscernible. The mechanisms and neuroanatomic points of action remain elusive. Therefore, this therapy remains being questioned. To gain objective experimental data about IFC stimulation, we examined this method ex-vivo in an isolated perfused porcine rectum including the mesorectum. To elucidate the role of plexus nerve fibers and enteric ganglia, we performed IFC stimulation also in the presence of tetrodotoxin or hexamethonium. We applied the commonly used stimulation modes with a beat frequency sweeping between 5-25Hz (IFCd5-25) and 80-150Hz (IFCd80-150). We monitored intraluminal pressure and motility by online barometry and video recording, respectively. Motor activity, reflected by changes in the intraluminal pressure (cmH2O s-1) and longitudinal movements (pixels s-1), was quantified over time as Root Mean Squares (RMS). After IFCd5-25 we observed a 30% increase of the rectal motility in the pressure changes which was sustained over 30 minutes post stimulation (p<0.02); only a minor effect was detected for IFCd80-150. Both tetrodotoxin and hexamethonium abolished the stimulation. This suggests neuronal modulation. IFCd5-25 stimulates rectal motor activity in the isolated perfused porcine rectum. Ganglia in the enteric nervous system are modulated to allow increased activity throughout at least 30min. Therefore, the isolated porcine rectum is a suitable tool to study the effectiveness of various IFC settings in the rectum.

Predictive uncertainty in state-estimation drives active sensing.

Animals use active sensing movements to shape the spatiotemporal characteristics of sensory signals to better perceive their environment under varying conditions. However, the underlying mechanisms governing the generation of active sensing movements are not known. To address this, we investigated the role of active sensing movements in the refuge tracking behavior ofEigenmannia virescens, a species of weakly electric fish. These fish track the longitudinal movements of a refuge in which they hide by swimming back and forth in a single linear dimension. During refuge tracking,Eigenmanniaexhibits stereotyped whole-body oscillations when the quality of the sensory signals degrades. We developed a closed-loop feedback control model to examine the role of these ancillary movements on the task performance. Our modeling suggests that fish may use active sensing to minimize predictive uncertainty in state estimation during refuge tracking. The proposed model generates simulated fish trajectories that are statistically indistinguishable from that of the actual fish, unlike the open-loop noise generator and stochastic resonance generator models in the literature. These findings reveal the significance of closed-loop control in active sensing behavior, offering new insights into the underlying mechanisms of dynamic sensory modulation.

Intelligent Vehicle Trajectory Tracking Based on Horizontal and Vertical Integrated Control

To address the common issues of accuracy and stability in trajectory tracking tasks for autonomous vehicles, this study proposes an innovative composite control strategy that skillfully integrates lateral and longitudinal dynamic control. For lateral control, model predictive control (MPC) theory is introduced to compute the front wheel steering angle that ensures optimal trajectory following. On the longitudinal control level, the vehicle’s acceleration and deceleration logic are finely tuned to ensure precise adherence to the preset speed trajectory. More importantly, by deeply integrating these two control methods, the comprehensive coordination of the vehicle’s lateral and longitudinal movements is achieved. To validate the effectiveness of the proposed control strategy, simulations were conducted using the CarSim and MATLAB/Simulink platforms. The analysis of the simulation results confirms that the proposed method effectively improves speed tracking stability and significantly enhances path tracking accuracy and overall driving stability.

Left Ventricular Strains and Right Ventricular Longitudinal Shortening Are Associated in Healthy Adults-A Detailed Analysis from the Three-Dimensional Speckle-Tracking Echocardiographic MAGYAR-Healthy Study.

The right ventricle (RV) lies on the left ventricle (LV), and their shapes and movements are characteristic and significantly different. The aim of the present study was to investigate the relationship between three-dimensional speckle-tracking echocardiography (3DSTE)-derived LV strains, which represent LV contractility as quantitative features, and tricuspid annular plane systolic excursion (TAPSE) as determined by M-mode echocardiography, which represents the longitudinal movement of the RV, in healthy adults. A total of 79 healthy adults (mean age: 28.1 ± 6.3 years; 33 men) were enrolled in the present study. After two-dimensional Doppler echocardiography, 3DSTE-derived data acquisition was carried out in all cases, and detailed 3DSTE-based analysis was performed offline at a later date. Reduced TAPSE was associated with increased global and basal LV radial strain (RS). Increased TAPSE was also associated not only with increased global and basal LV-RS but also with global LV longitudinal strain (LS). An increase in global LV-RS and global LV circumferential strain (CS) showed associations with other strains except for global LV-LS. An increase in global LV-LS did not show associations with other strains. Increased global LV-RS was associated with reduced TAPSE, while the degree of global LV-LS and global LV-CS did not show associations with TAPSE. Three-dimensional speckle-tracking echocardiography-derived LV-RS and LV-LS are associated with the longitudinal shortening of the RV represented by TAPSE in healthy adults.

Identifying possible ways for adapting an open wagon for transporting containers

The object of this study is the processes of perception and redistribution of loads in the supporting structure of a open wagon loaded with containers, taking into account the new scheme of their fastening. For safe transportation of containers in an open wagon, it is suggested to use a removable module. This module works according to the principle of an intermediate adapter between the container and the open wagon body. Fastening of the module itself in the open wagon is carried out through the fitting stops, which are placed on the floor of the open wagon. Mathematical modeling was carried out to determine the longitudinal dynamic load acting on the container fixed according to the new scheme in the open wagon. To this end, a mathematical model was built that characterizes the longitudinal movements of the "open wagon - removable module - container" system. Determination of the accelerations that act on the supporting structure of the open wagon loaded with containers was also carried out by means of computer simulation. Verification of the formed model of the dynamic load of the open wagon was carried out according to the F-criterion. Also, as part of the study, a modal analysis of the load-bearing structure of a open wagon loaded with containers was carried out, which made it possible to assess its traffic safety. A feature of the results obtained as part of the research is that the proposed design of the removable module could be used not only for fastening containers but also for transportation of other types of cargo. The field of practical application of the results is railroad transport, including other transportation industries. The conditions for the practical use of the results are a symmetrical scheme of loading the body of a open wagon with containers. The results of this study will contribute to increasing the efficiency of container transportation and the profitability of railroad transport

Effects of Toe-Strengthening Exercises on Medial Longitudinal Arch Height, Muscle Stiffness, and Functional Movement

Background: Prolonged training in combat boots can place significant stress on the medial longitudinal arch, potentially leading to lower-extremity muscle stiffness and an increased risk of injury. This study assessed the impact of toe-strengthening exercises on improving the lower-extremity function and functional movement in cadets undergoing training. Methods: Forty junior cadets (mean age: 22.6 years) participated in this study. The measurements included the medial longitudinal arch height, lower-extremity muscle stiffness, functional movement, and leg length. Results: Cadets who performed the toe exercises demonstrated improved lower-extremity muscle stiffness and functional movement performance (hurdle step, p = 0.010; rotary stability, p = 0.001). A significant correlation was observed between the exercise group and time (tibialis right, p = 0.008; tibialis left, p = 0.028). Conclusions: This study highlighted the potential of toe-strengthening exercises to enhance the lower-extremity function and reduce the risk of injury among cadets. However, challenges in identifying the medical history, past injuries, and specific areas of pain for each cadet were noted. These findings support the implementation of targeted toe exercises in military training programs to prevent injuries.

Analysis of the left atrial appendage function by intracardiac echocardiography in patients with atrial fibrillation

Abstract Introduction Intracardiac echocardiography (ICE) is frequently performed during catheter ablation procedures in order to guide the transseptal puncture and has been recently used to evaluate the morphology of the LAA. Purpose The objective of this study was to evaluate the feasibility of using an ICE catheter placed in the coronary sinus (CS) to delineate the LAA function during catheter ablation for atrial fibrillation. Methods We included 21 consecutive patients (age 62±9 years, 5 women, 6 paroxysmal AF) who underwent catheter ablation for AF. An 8-Fr phased-array ICE catheter was used to obtain images of the LAA, while in sinus rhythm. The LAA was visualized with the ICE probe placed sequentially in the left atrium (LA, Figure A), with the ultrasound section plane parallel to the long axis of the left ventricle (LV), and in the CS, with the ultrasound section plane perpendicular to the LV long axis (Figure B). LAA emptying flow velocity, and LAA fractional area change (FAC) were used to evaluate LAA function. There were no procedural complications. Results ICE imaging was possible in all cases. The LAA peak flow velocity was similar when the ICE catheter was placed in the LA and in the CS (64±7 cm/s and 62±5cm/s respectively, P=NS). The LAA FAC was significantly lower when the ICE catheter was placed in the CS when compared to an LA location (14±6% vs 36±14%; P&amp;lt;0.001). The LAA FAC measured from the LA correlated with the mitral annular plane systolic excursion while the LAA FAC measured from the CS did not. Thus, LAA contraction in a plane perpendicular to the LV long axis is independent of the LV longitudinal contraction. These results suggest that in our patient group most of the LAA contraction was due to the longitudinal movement of the LV base during systole and diastole. Conclusions Imaging of LAA using an ICE probe positioned in the LA and CS was feasible in all cases. The LV longitudinal contraction appears to impact the LAA function.

TO THE ISSUE OF SOIL VARIOUS TYPES INFLUENCE ON PIPELINE LONGITUDINAL MOVEMENT

Achieving and maintaining the required reliability of the linear part of the main gas pipelines is of great importance. Emergency destruction usually leads to large gas leaks into the atmosphere and undersupply to consumers, significant costs for the restoration of main gas pipelines. The rise in cost of repair work on main gas pipelines directly depends on the difficult conditions of the route. Special technical solutions are to be used for achieving the necessary stability and reliability of pipelines on low-bearing soils. Thus, on operating gas pipelines at variable temperatures of the transported product, their longitudinal movements occur, resulting in longitudinal forces appearance and correspondingly in increase of gas pipeline stress state and their possible destruction. The significant period of time of increase in gas pipeline movements indicates that these changes in pipeline position occur due to the rheological properties of soils. An analysis of the stress state of such sections of gas pipelines is necessary to assess their operational reliability and, as a result, the timing and methods of repair. This article discusses the maximum values of longitudinal displacements of a pipeline laid in various soils and the deflection values corresponding to these models for potentially dangerous sections.

Jaw-neck motor function 2 years after whiplash trauma.

There is limited knowledge about the possible long-term effects on jaw motor function after whiplash trauma. The primary aim was to evaluate integrated jaw and head-neck movement amplitudes during jaw function in individuals 2 years after whiplash trauma, compared to controls. The secondary aim was to evaluate changes between the acute stage and a 2-year follow-up in terms of jaw and head-neck movement amplitudes during jaw function. This study included 28 cases exposed to a whiplash trauma 2 years earlier (13 women) and 28 controls (13 women) without previous neck trauma. Head and jaw movement amplitudes were recorded during maximal jaw opening-closing movements using an optoelectronic 3D recording system. For a subpopulation of 12 cases and 15 controls, recordings had also been performed in the acute stage after the whiplash trauma. Jaw and head movement amplitudes were analysed using linear regression with group and sex as independent variables. The subpopulation longitudinal analysis was adjusted for movement amplitudes at baseline. Jaw movement amplitudes were significantly associated with group (coefficient: -0.359: 95% CI: -10.70 to -1.93, p = .006) with smaller amplitudes of jaw movements for whiplash cases. Head movement amplitudes were not associated with group (coefficient: -0.051, 95% CI: -4.81 to 3.20, p = .687). In the longitudinal analysis, both jaw and head movement amplitudes showed significant associations between baseline and the 2-year follow-up. The present findings indicate that the effects on jaw function in terms of jaw opening capacity in the acute stage after whiplash trauma do not spontaneously recover.

Single-file movement of pedestrians at different visibility levels

Previous studies indicate that the movement of pedestrians under poor visibility conditions is significantly different from that under good visibility conditions. To investigate the influence of visibility factor on the longitudinal movement of pedestrian, series of single-file experiments were performed under the quantitative control of visibility level. Based on the extracted trajectories, typical evacuation behavior and movement characteristics of pedestrians under different visibility conditions are explored. It is found that the lateral swing amplitude of pedestrians during movement is within 20 cm under low densities while it is close to 30 cm at high densities. The free velocity under the light transmission of 100 %, 2.2 %, 0.5 % and 0.1 % is 0.856 m/s, 0.823 m/s, 0.741 m/s and 0.712 m/s respectively. Individuals cannot accurately perceive the surrounding situations with the worsening of visual condition, therefore the movement speed decreases under the poor visibilities. Besides, two regimes including the constrained regime and free regime are identified in the headway-velocity relation at different visibility levels. The maximum specific flow under the light transmission of 100 %, 2.2 %, 0.5 % and 0.1 % is 0.70 s−1, 0.67 s−1, 0.62 s−1 and 0.55 s−1 respectively. The study is helpful to reveal the pedestrian dynamics of single-file movement under the limited visibility conditions.

Range selective digital holographic imaging of vibrating objects using FMCW lidar

The use of frequency modulated continuous wave (FMCW) chirped transmit and reference waveforms in digital holographic (DH) imaging has enabled range selectivity. By frequency shifting the reference beam to compensate for the typical FMCW lidar beat frequency associated with a particular range, a temporally stable holographic image is formed for objects at the selected range and coherently integrates on a short wave infrared (SWIR) sensor. For vibrating objects, longitudinal movements of the object greater than half of an optical wavelength during the exposure time of the sensor array induce phase shifts that can wash out the hologram. An analog feedback system was designed and constructed whereby a lidar subassembly provides real time phase compensation information to a DH subassembly in order to stabilize the range selective digital holographic recording of the object. The design and characterization of the feedback system, as well as the results demonstrating the performance for vibrating objects that move over 17 wavelengths during the sensor exposure, are discussed.

FEATURES OF CALCULATING LONGITUDINAL DISPLACEMENTS OF PIPELINES LAID IN HETEROGENEOUS SOILS

Achieving and maintaining the required reliability of the linear part of the main gas pipelines is of particular importance. Emergency destruction usually leads to large gas leaks into the atmosphere and undersupply to consumers, significant costs for the restoration of main gas pipelines. The difficulty and cost of carrying out repairs of main gas pipelines directly depends on the difficult conditions of the route and special technical solutions are needed to achieve the stability and reliability of pipelines on low-bearing soils. Thus, on existing gas pipelines, their longitudinal movements occur under the action of longitudinal forces, which leads to an increase in the stress state of gas pipelines and even the destruction of pipes. The significant time duration of the increase in gas pipeline movements indicates that these movements occur due to the rheological properties of soils. An analysis of the stress state of such sections of gas pipelines is necessary to assess their reliability, timing and methods of repair.

HITCH DEVICE MODERNIZATION FOR TRANSLOADING OF BALE CARGO

The operation of unloading bales from a covered railway wagon is one of the most labor-intensive and dangerous operations when transporting bale cargo. The article proposes a modernized outside-mounted load-handling device for a universal light-sized forklift. The device is a mechanical equipment for transloading of bale cargo. The device includes a push-pull attachment (a purchased part) on which a frame, a lever clamp and a hydraulic cylinder are mounted. Тtrolleys are installed on the forks of the loader. The trolley is equipped with a roller in the front part and a frame in the back part for longitudinal movement on the forks. The trolley also has a support for the movable pusher plate and a grip for lifting the front edge of the bale. The trolleys are connected to the stationary pusher plate by a lever-type limiter. Before the start of gripping, the forklift is tilted forward at an angle from 3 to 5°, the trolleys are in the most forward position and are supported by a pusher. In this case, the rollers are in the position where they have moved off the forks. By moving the forklift forward, the trolley grips are inserted under the bale. The pusher is brought into the folded state. The loader moves forward, the noses of the forks abut against the roller and it rolls onto the forks, lifting the front edge of the bale. The forks are fully inserted under the bale. The clamp comes into operation, holding the load on the forks. This allows the bales to be removed from the stack and transported. The trolley was designed using CAD KOMPAS-3D. The proposed device is capable of picking up bales stacked without gaps and can be used inside a covered railway wagon. Commonly used side-clamp devices are not capable of this. The mathematical relation of the required traction force of the loader on the geometric parameters of the trolley is derived. It has been established that the required traction force is 60 to 70 % of the maximum traction force achieved by light-sized forklifts with a lifting capacity of 1000 kg.

Enhancing longitudinal performance in railway suspension bridges through an integrated cable restrainer system

Longitudinal motion is a crucial factor affecting the fatigue life of expansion joints, bearings, dampers and short suspenders in suspension bridges. Traditional control methods relying solely on fluid viscous dampers often magnify the relative displacement between the main cable and the girder (hereafter referred to as relative displacement), leading to fatigue problems in the short suspenders. To overcome these shortcomings, an Integrated Cable Restrainer System is proposed. Firstly, a suspension bridge is described, and both a Refined Finite Element Model (RFEM) and a Simplified Finite Element Model (SFEM) are developed and compared. Subsequently, the effectiveness of three cable measures in reducing the longitudinal motion response and the relative displacement of the bridge is evaluated: the cable central buckle (Type I, connecting the main cable and the girder), the inclined control cable (Type II, controlling the main cable) and the longitudinal control cable (Type III, controlling the girder). Finally, an Integrated Cable Restrainer System integrating type I to type III measures is proposed and compared with FVDs, and its control benefits on train and seismic induced vibration are discussed. The results indicate that the SFEM has a higher calculation efficiency while maintaining comparable accuracy. All three types of cable restrainers are effective in controlling the longitudinal movement of the girder end, although type III increases the relative displacement. The Integrated Cable Restrainer System not only effectively controls longitudinal motion (induced by trains and seismic events) but also reduces the relative displacement at the short suspender positions. By employing the Integrated Cable Restrainer System combined with dampers for controlling longitudinal motion, the undesirable effects associated with damper usage can be effectively mitigated. This research serves as a valuable reference for bridge design and longitudinal motion control in suspension bridges. Data AvailabilitySome or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.

High-Coupled Magnetic-Levitation Hybrid Nanogenerator with Frequency Multiplication Effect for Wireless Water Level Alarm.

Hybrid nanogenerators (HNGs) represent a promising avenue for water energy harvesting, yet their commercial viability faces hurdles such as limited power output, poor coupling, and constrained operational lifespans. Here, a highly coupled triboelectric-electromagnetic magnetic-levitation hybrid nanogenerator (ML-HNG) is introduced that shows great potential for water energy harvesting. The ML-HNG fulfills the challenges of high power output, strong coupling, and long operational lifespans. During the contact-separation process of the triboelectric nanogenerator (TENG), the changing magnetic flux in the electromagnetic generator's coils generates a potential difference between the coils and Cu electrodes. The unique design of the ML-HNG employs a shared coil electrode configuration, which enhances the coupling without adding extra volume. This integration allows the ML-HNG to achieve multi-frequency vibrations and multiple output cycles per external longitudinal movement, a phenomenon known as the frequency multiplication effect. With an average power density of 1.69W m-3 in water, the ML-HNG provides continuous power for a thermo-hygrometer and can quickly drive a wireless water level alarm system within a minute. This groundbreaking hybrid nanogenerator design holds significant promise for the efficient and consistent harvesting of low-frequency ocean wave energy, marking a substantial advancement in blue energy technology.

On integrated lateral and longitudinal control of brain-controlled vehicles

A brain-controlled vehicle (BCV) is a vehicle that uses the Brain–Computer interface (BCI) to analyze the driver’s electroencephalogram (EEG) to obtain human control commands, which can help disabled people extend movement range and improve their self-independence. At this stage, research on the control of BCVs usually focuses only on the lateral control or longitudinal control, and few studies have focused on the problem of integrated lateral and longitudinal control. Given this situation, this paper investigates the integrated control of brain-controlled vehicles (BCV) in both lateral and longitudinal directions, and proposes a control method that utilizes speed as the coupling point. Firstly, the vehicle’s speed is determined by the provided road information. To control the vehicle’s longitudinal speed, a hierarchical control method based on model predictive control (MPC) is implemented. This method introduces a threshold σ to speed up the calculation process and reduce resource consumption. Then, a global controller is developed to conduct the motion control. This controller utilizes three local ANFIS intelligent controllers, employing soft-switching combinations, to generate the steering wheel angle signal. The generated steering wheel angle signal is combined with the cornering command issued by the driver. This fusion process produces the final command, which is responsible for the vehicle’s motion control. Finally, a simulation model is developed to test the integrated control of the BCV in terms of both lateral and longitudinal movements. Multiple experiments are conducted under varying conditions, and the results prove that the proposed method is able to complete the integrated control of the BCV well, which fully illustrates its effectiveness.

A cellular automaton model for mixed traffic flow considering the size of CAV platoon

In the environment of intelligent connected vehicles, the mixed traffic flow consisting of human-driven vehicles (HDVs), connected and automated vehicles (CAVs), and their platoons will coexist for a long time. Exploring and discovering the operational rules of mixed traffic flow is the foundation for its management and control. This study delves into the distinct characteristics of various vehicles within a mixed traffic environment, particularly focusing on HDVs, CAVs, and CAV platoons. Drawing on the psychological predisposition of HDVs to maintain a prudent following distance, we introduce a discrete motion safety distance model to establish the longitudinal movement rule for HDVs. Furthermore, a longitudinal movement rule for CAVs is established based on their ability to keep a constant headway using Adaptive Cruise Control (ACC) and Cooperative Adaptive Cruise Control (CACC), alongside meeting specific speed and spacing criteria for platoon movement. On this basis, the paper proposes a cellular automaton model for single-lane mixed traffic flow that accounts for CAV platoon length and the decision-time disparity between HDVs and CAVs. The simulation results show that an increased proportion of CAVs can enhance the traffic capacity, elevate average speed, extend average platoon length, and reduce the congestion ratio and CACC degradation rate. Notably, in scenarios where the CAV proportion p > 0.7, the flow-density graph shows a trapezoidal shape, with the majority of CAVs in the traffic flow synchronizing their movements in CACC mode. Even when vehicular density surpasses the optimum threshold, the traffic flow maintains high-speed operation until reaching a critical congestion point, whereupon velocities precipitously decline. Through sensitivity analysis aimed at understanding the impact of maximum platoon length, it has been observed that, for CAV proportions below 0.7, variations in maximum platoon length negligibly impact traffic capacity, velocity, CACC degradation, and congestion levels. Only in scenarios dominated by CAVs does extending platoon length restrictions significantly enhance performance. However, as the maximum platoon length increases, the gains in traffic capacity, speed, CACC degradation rate, and congestion ratio diminish. When the platoon length of CACC exceeds a certain threshold, there will not be a significant improvement in traffic capacity or speed.

Effects of ingesting large prey on the kinematics of rectilinear locomotion in Boa constrictor.

Large and stout snakes commonly consume large prey and use rectilinear crawling; yet, whether body wall distention after feeding impairs rectilinear locomotion is poorly understood. After eating large prey (30-37% body mass), all Boa constrictor tested could perform rectilinear locomotion in the region with the food bolus despite a greatly increased distance between the ribs and the ventral skin that likely lengthens muscles relevant to propulsion. Unexpectedly, out of 11 kinematic variables, only two changed significantly (P<0.05) after feeding: cyclic changes in snake height increased by more than 1.5 times and the longitudinal movements of the ventral skin relative to the skeleton decreased by more than 25%. Additionally, cyclic changes in snake width suggest that the ribs are active and mobile during rectilinear locomotion, particularly in fed snakes, but also in unfed snakes. These kinematic changes suggest that rectilinear actuators reorient more vertically and undergo smaller longitudinal excursions following large prey ingestion, both of which likely act to reduce elongation of these muscles that may otherwise experience substantial strain.

Research on Intelligent Platoon Formation Control Based on Kalman Filtering and Model Predictive Control

Recently, the intelligent platoon has attracted a lot of attention in both academic and industrial research. For each intelligent platoon, all vehicles drive sequentially in a line, which helps to improve fuel economy and road capacity. Consider two adjacent vehicles in the intelligent platoon, and there is no mechanical boundary between them. However, an intelligent platoon may still suffer from the issues of poor vehicle-following performance during the process of vehicle-following, especially when it obtains its own position and other parameters inaccurately. To address this issue, this paper proposes a model predictive control method based on an improved version of Kalman filtering, aiming to enhance the anti-interference capacity of intelligent platoons in scenarios where the following vehicles have acquired inaccurate parameters resulting from environmental disturbances and sensor noise. Firstly, this paper establishes a three-degree-of-freedom single-track model for the following vehicle, conducting dynamic analysis of its lateral, longitudinal, and yaw movements. Then, this paper develops a horizontal and longitudinal formation driving control frame of the intelligent vehicle platoon. Moreover, this paper also has employed Kalman filtering for interference reduction of state parameters and designs an improved model predictive controller. The proposed scheme is verified and evaluated through a joint simulation within Carsim and MATLAB/Simulink, and the results demonstrate that the longitudinal following error is reduced by 37% and the lateral following error is reduced by 51% compared to traditional algorithms, effectively improving the stability of intelligent vehicle platoons during following driving.