Lateral Deviation Research Articles

Utilization of Vestibular Information for Balance Control in Children with Chiari I Malformation

(1) Background: Surgery for Chiari I malformation (CMI) is indicated when typical clinic-radiological features (syringomyelia, exertional headaches, sleep apnea syndrome, and tetraparesis) are present. Sometimes, patients have atypical complaints suggestive of otolaryngological (ENT) involvement, and it is sometimes difficult for the neurosurgeon to determine if these complaints are related to the CMI. Our aim was to describe postural control patterns in children with CMI using computerized dynamic posturography. To our knowledge, this is the first study addressing postural instability in pediatric CMI patients. (2) Methods: Twenty-eight children aged 6 to 17 years with both radiologically confirmed CMI and clinical ENT complaints were included. The children were separated into two groups, operated and non-operated patients, based on neurosurgical indication. Epidemiologic and posturographic results (CDP—Equitest®) were compared between both groups, as well as pre- and postoperatively in Group 2. (3) Results: In Group 2 patients, significant improvement of global SOT was found after intervention. When the three sensorial aspects of postural control calculated by the system were independently assessed, the greatest improvement was in the vestibular ratio. We also observed an altered CoG pattern (“lateral deviation”) in the Group 2 patients, which significantly differed from those in Group 1. Lateral deviation was significantly reduced postoperatively in the Group 2 patients. A correspondence between preoperative MRI and the side of lateralization on posturography was found in four children, but this cannot be regarded as significant due to the low number of patients. (4) Conclusions: Postural control seems to improve after surgery for CMI in children, mostly due to the improvement in vestibular function. There is a correspondence between the side of lateral deviation and the side of greatest tonsillar descent on MRI and perioperatively. Further studies are needed to support these results and to confirm the utility of CDP in CMI patients.

Integrated Navigation Method for Orchard-Dosing Robot Based on LiDAR/IMU/GNSS

To enhance the localization reliability and obstacle avoidance performance of the dosing robot in complex orchards, this study proposed an integrated navigation method using LiDAR, IMU, and GNSS. Firstly, the tightly coupled LIO-SAM algorithm was used to construct an orchard grid map for path planning and obstacle avoidance. Then, a global localization model based on RTK-GNSS was developed to achieve accurate and efficient initial localization of the robot’s coordinates and heading, and a Kalman filter was applied to integrate GNSS and IMU to improve robustness. Next, an improved A* algorithm was introduced to ensure the global operational path maintained a safe distance from obstacles, while the DWA algorithm handled dynamic obstacle avoidance. Field tests showed that the global localization model achieved an accuracy of 2.215 cm, with a standard deviation of 1 cm, demonstrating stable positioning performance. Moreover, the global path maintained an average safe distance of 50.75 cm from the obstacle map. And the robot exhibited a maximum absolute lateral deviation of 9.82 cm, with an average of 4.16 cm, while maintaining a safe distance of 1 m from dynamic obstacles. Overall, the robot demonstrated smooth and reliable autonomous navigation, successfully completing its tasks.

Can retroreflective rings enhance drivers’ safety perception of spatial right-of-way in freeway tunnels? A simulation exploration

In order to investigate whether retroreflective rings can enhance drivers’ perception of spatial right-of-way in freeway tunnels, this paper explores a simulation test. The characteristics of spatial right-of-way in tunnels are elucidated, and a comparative test is conducted using commonly used delineators and raised pavement markers against retroreflective rings to enhance the perception of spatial right-of-way. The test employs the perception of lateral deviation and longitudinal distance as indicators to reflect the lateral and longitudinal right-of-way. Video scenarios, incorporating different facilities and spacing, are created using 3Ds Max software following the design standards of freeway tunnels. The indicators of Stimulation of Subjectively Equal Distance (SSED), lateral deviation, and perception reaction time (PRT) are chosen to assess the effects of different facilities on drivers under varying spacing conditions. Fifty-two participants, divided into two groups of novice drivers and experienced drivers, underwent perception testing in a simulated driving environment. The results indicate that drivers exhibit the highest overestimation of longitudinal distance and the longest PRT of lateral deviation in the absence of facilities. Installing retroreflective rings with a spacing of 50–200 m significantly mitigates the overestimation of longitudinal distance, while reducing the PRT of lateral deviation. On the other hand, setting up delineators and raised pavement markers with a spacing of 6–12 m significantly reduces the PRT of lateral deviation, while there is no significant enhancement to the perception of longitudinal distance. A spacing of 200 m for retroreflective rings and 10 m for delineators and raised pavement markers in the straight section is recommended as a safer and more economical setting scheme. The combination of these facilities can enhance drivers’ safety perception of spatial right-of-way in freeway tunnels, facilitating rapid perception, correct judgment, and timely decision-making for the safe passage of vehicles.

Beam Local Stress Prediction Model for Incremental Launching Construction Based on SSA-SVR Algorithm

In the multi-point incremental launching construction process, without setting temporary piers at the mid-span, it is difficult to ensure the synchronization of the launching equipment at the same pier, which can easily cause the beam to deviate from the design axis, leading to changes in the stress of the beam. Calculating the local maximum stress of the beam when lateral deviation occurs is beneficial for establishing a reasonable and reliable threshold for controlling beam deviations. To address this issue, this paper utilizes a finite element model of the bridge under typical adverse conditions, simulating the lateral deviation and asynchronous jacking of the beam to explore stress variation patterns. The results show that the beam stress increases as the lateral deviation and jacking differences increase, severely affecting the structural safety. To overcome the inefficiency of the finite element modeling method when dealing with multiple working conditions and to establish a reasonable deviation control threshold, this study proposes a beam local stress prediction model under the combined influence of lateral deviation and jacking height differences based on the SSA-SVR algorithm. The model calculates the local maximum stress of the beam for 2500 sets of parameters. An engineering case analysis shows that the prediction model has high calculation accuracy, reliable results, fast computational speed, and high efficiency. Based on the stress prediction results, it is recommended to set the jacking height difference control threshold at 20 mm. When the jacking height difference is less than 20 mm, the local maximum stress value under the combined influence of both parameters should be less than the standard limit. The corresponding lateral deviation control threshold can be dynamically adjusted according to the actual travel difference recorded by the jacking equipment, with the control precision improved to 1 mm.

Digital Analysis of Closest Speaking Space in Dentates—Method Proposal and Preliminary Findings

Aims: The aim of this study is to identify methods for the digital analysis of the closest speaking space in dentates and to assess certain particularities using digital analysis. Method: For the adult patients included in this study, traditional dental casts were fabricated, and interocclusal registrations of the maximal intercuspal position and of the closest speaking space were taken using polyvinyl siloxane. Dental casts in both positions were scanned using a dental laboratory scanner, and digital analysis was conducted using the 3Shape 3D Viewer. Results: The interocclusal distance corresponding to the closest speaking space can be easily and precisely measured digitally or assessed using occlusion maps, at the level of all teeth. The interocclusal distance was variable across the dental arch, central incisors, and second molars, registering the smallest values, and was asymmetrical, with mandibular lateral deviation being suggested. The assessment of the range of motion of the mandible during the speaking test, recorded based on tooth movement, was conducted using superimpositions. The movement of the tooth was the largest in central incisors and decreased progressively as the tooth was more distal, and, in all cases, mandibular deviation occurred, more frequently to the left. Conclusions: Digital methods for the analysis of the closest speaking space have the advantages of increased precision and a broader range of analysis and application, showing research and clinical value.

Unmanned Agricultural Machine Operation System in Farmland Based on Improved Fuzzy Adaptive Priority-Driven Control Algorithm

Autonomous driving technology for agricultural machinery can maximise crop yield, reduce labour costs, and alleviate labour intensity. In response to the current low degree of automation and low tracking accuracy of driving paths in agricultural equipment, this research proposes an unmanned agricultural machinery operating system based on an improved fuzzy adaptive PD control algorithm. Firstly, mechanical kinematic models and fuzzy adaptive control algorithms are introduced to achieve autonomous driving, and parameter settings and speed adjustments are made while considering errors. Secondly, in the autonomous driving operation system, taking a certain rice machine as an example, perception information, trajectory design, dynamic control, operation supervision, and remote control design are carried out. The experimental results show that the improved fuzzy algorithm exhibits smaller deviation results in driving path tracking, with an average error between the actual path and the expected path of less than 0.001 m. In different testing scenarios, compared with the actual control results, the maximum deviation of the control system platform in straight sections is less than 2.8 m, which is more stable. More than 95% of the lateral deviation results in the road sections are within 0.11 m. And the tracking distance error of the proposed method in the straight and curved segments is relatively small, far smaller than other comparative algorithms. The unmanned agricultural machinery operation system proposed in this study can significantly improve the efficiency and accuracy of agricultural machinery work, promote the development of intelligent and modern agricultural machinery, and provide reference value and important contributions to social and economic development as well as the progress and promotion of related technologies.

Integrated Control of Intelligent Vehicle Driving Stability Using Three-Dimensional Phase Space

<div>To enhance vehicle dynamic stability during driving, we developed a three-dimensional phase space model that incorporates the sideslip angle of center of mass, yaw rate, and lateral load transfer rate. This model enabled real-time evaluation and active control of vehicle stability. First, longitudinal and lateral controllers were implemented to ensure precise vehicle trajectory. Second, a hierarchical control strategy was designed to actively manage the desired sideslip angle, yaw rate, and roll angle based on the vehicle’s destabilizing conditions, thereby maintaining the vehicle within a stable state space. We simulated and tested the stability analysis methods and integrated control strategies for both cars and trucks under DLC (double lane change) and CDC (circular driving condition) scenarios using joint simulations with CarSim/TruckSim and Simulink. The proposed integrated stability control strategy, which combined MPC-based trajectory tracking with direct yaw moment control and active suspension control, enhanced the vehicle’s directional and roll stability. This approach effectively mitigated vehicle instability under extreme conditions. Compared to the MPC lateral tracking control system, the performance of the integrated control system was significantly improved. In the DLC scenario, the maximum values of the sedan’s lateral deviation, sideslip angle, yaw rate, and vehicle roll angle decreased by 22.6%, 33.9%, 5.5%, and 1.2%, respectively. In the CDC scenario, the truck’s lateral acceleration, sideslip angle, yaw rate, and vehicle roll angle decreased by 7.5%, 46.8%, 8.2%, and 80%, respectively. Additionally, open-loop simulation tests were conducted under fishhook steering conditions for both passenger cars and trucks. The results further validated the effectiveness of the integrated control strategy, demonstrating its ability to significantly improve yaw rate and roll response, thereby enhancing overall vehicle stability under challenging driving conditions.</div>

An Unusual Skin Finding in a Rare Case of Goltz Syndrome

Abstract Introduction/Objective Goltz Syndrome (Focal Dermal Hypoplasia) is a rare X linked dominant genetic disorder with various dermatologic, musculoskeletal and neurologic manifestations, secondary to a mutation in the PORCN gene. Skin findings include telangiectasias, raspberry-like papillomas (angiofibroma like lesions), nodular fat herniation, xerosis and photosensitivity. Lesions are bilateral, and asymmetrically distribututed along the lines of Blasco. The adipocytic lesions can be diagnosed via a skin biopsy showing adipose tissue in the superficial epidermis and dermis or via molecular techniques showing a mutation in the PORCN gene. Here we report a case of Goltz Syndrome with unique dermal findings. Methods/Case Report A male infant presented at birth with mild diffuse xerosis, large hypopigmented and depigmented atrophic patches and plaques and multiple pink yellow red exophyitic soft papules distributed asymetrically across the body along the lines of Blascho. Additionally the patient had clinodactly, widely spaced nipples, extra pads of fat in the toes and philtrum and fingernails with longitudal ridges and lateral nail plate deviation. A diagnosis of Goltz syndrome was made via molecular analysis that showed mosiacism at C.502G>A (p.Gly168Arg) in the PORCN gene. The patient had a very superficial 2-3 mm erosion at the intersection between the scrotum and perineum. At 18 months, this had grown to finger like projections and eventually grew into multiple tan red exophytic warty papillomatous telangactatic like lesions measuring 3.0 x 0.8 cm that were painful and bled easily. A biopsy of this lesion showed focal mild epidermal hyperplasia and elongation of the rete ridges with wide spread diffuse vascular proliferation with multiple ectactic vessels along with mild dermal and perivascular inflammatory infiltrates. Also noted was infiltration of mature adipose tissue in the superficial epidermis and dermis. We preformed elastin and trichrome stains to identify if this lesion was reactive in nature or de novo. Our results showed retained elastin staining with a negative trichrome eluding to a denovo process. Additionally GLUT1 was negative, ruling out an infantile hemangioma. The above findings in this lesion do not represent any previously described dermatologic entity. Results (if a Case Study enter NA) NA Conclusion This is a rare and unique dermatologic finding of a case of Goltz sydrome, which itself is a rare disorder. In our literature review, this is the only case of Goltz Syndrome thusfar to have presented with this unique skin lesion.

Lateral-Stability-Oriented Path-Tracking Control Design for Four-Wheel Independent Drive Autonomous Vehicles with Tire Dynamic Characteristics under Extreme Conditions

This paper proposes a lateral-stability-oriented path-tracking controller for four-wheel independent drive (4WID) autonomous vehicles. The proposed controller aims to maintain vehicle stability under extreme conditions while minimizing lateral deviation. Firstly, a tiered control framework comprising upper-level and lower-level controllers is introduced. The upper-level controller is a lateral stability path-tracking controller that incorporates tire dynamic characteristics, developed using model predictive control (MPC) theory. This controller dynamically updates the tire lateral force constraints in real time to account for variations in tire dynamics under extreme conditions. Additionally, it enhances lateral stability and reduces path-tracking errors by applying additional yaw torque based on minimum tire utilization. The lower-level controllers execute the required steering angles and yaw moments through the appropriate component equipment and torque distribution. The joint simulation results from CarSim and MATLAB/Simulink show that, compared to the traditional MPC controller with unstable sideslip, this controller can maintain vehicle lateral stability under extreme conditions. Compared to the MPC controller, which only considers lateral force constraints, this controller can significantly reduce lateral tracking errors, with an average yaw rate reduction of 31.62% and an average sideslip angle reduction of 40.21%.

Effect of Oral Somatosensory Training on Oral Somatosensory Dysfunction in Head and Neck Cancer Survivors.

The objective of this study was to determine the effect of an oral somatosensory training (OST) program on oral somatosensory dysfunction (OSD) in neck and head cancer survivors. One hundred and eight people with altered tastes were enrolled in this research based on inclusion and exclusion criteria and were randomized into groups A and B. Group A received conventional exercises whereas group B received OST. Focal sensations, subjective total taste acuity (STTA), objective taste test, range of motion (ROM), manual muscle testing (MMT), and MD Anderson Symptom Inventory-Head and Neck module (MDASI-HN) questionnaire were employed as outcome measures. To validate the outcomes, pre- and post-assessments of the above measures were conducted. Statistical analysis was done using SPSS statistical software (version 26.0). The results showed significant improvement in temperature (p= 0.0037, 0.0099, 0.0007, 0.0006), two-point discrimination (p<0.0001, 0.0010, 0.0112), light touch sensation (p<0.0001, 0.0006, 0.0055), STTA and ROM (p<0.0001), MMT scores depressors, elevators, retractors and lateral deviation and protrusion (p<0.0001) of patients undergoing OST as compared to conventional training. Also, the MDASI-HN questionnaire revealed the five most severe items in Group B being dry mouth, food taste problems, difficulty swallowing, mucus problems, and choking, and showed a significant decrease in the mean difference from 4.33±0.77, 8.4±0.40, 6.20±0.62, 5.92±0.69, 2.31±0.46 to 2.38±049, 3.09±0.44, 2.61±0.49, 2.48±0.50, and 0.27±0.45 as compared to Group A. The study concluded that OST program had shown a significant effect in improving OSD among head and neck cancer survivors.

The relationship between static and dynamic postural deformities with pain and quality of life in non-athletic women

BackgroundThe assessment of the postural condition with functional tests are used with the least facilities in the shortest time, for a wide the range of movements for different parts of the body. Both static and dynamic posture measurements are predictive of injury. These two assessments provide different information regarding posture control. Also, with the advancement of this technology, the speed of posture assessment and deformity diagnosis can be increased and done with the minimum facilities. This can signal a new method for the quick diagnosis of abnormalities and ultimately prevent or correct psychological effects and musculoskeletal pain in the future. Because as seen according to the citations, abnormalities cause musculoskeletal pains, movement restrictions and ultimately affect the quality of life.MethodsThe current research is of the applied and semi-experimental type, and in terms of the results it is of the relational and correlational type. In this research, 148 non-Athletic women from Fardis City participated, in which the results obtained from the static evaluation was analyzed by the Posture Screen application after taking photos from four directions using a smartphone, and also the dynamic evaluation was identified and analyzed by the researcher using the overhead squat test of compensatory movements, with the data that from Cornell pain and quality of life SF-36 questionnaires was. Data description and correlation between variables were done with the η coefficient method.ResultsAccording to the findings there is a positive and significant correlation between the prevalence of uneven pelvic deformity and the amount of pain in non-athletic women (P = 0.036, η (148) = 0.17). In other words, pain increased significantly when the pelvis was changed from a normal position to a lateral deviation position. Also, there is a negative and significant relationship between the prevalence of deformity of knee movement, back arch, straight back, heel lift and the quality of life in non-athletic women (P = 0.020, η (148) = 0.19).ConclusionsAccording to the results, deformities have an effect on pain and the frequency of pain, on the other hand, in the present study, dynamic evaluations showed deformities more accurately than static evaluations.

Arthroscopically Assisted Reconstruction of Lateral Metatarsosesamoid Suspensory and Lateral Metatarsophalangeal Collateral Ligaments in the Management of Iatrogenic Hallux Varus Deformity

The medial and lateral metatarsosesamoid suspensory ligaments together with the sesamoid apparatus are the main contributors to the rotational stability of the first metatarsophalangeal joint (MTPJ). Rotational instability of first MTPJ is a major factor in the development of hallux valgus and varus deformities. As the great toe starts to rotate, the muscle pulls across the first MTPJ, causing it to become imbalanced and lead to progressive medial or lateral deviation of the great toe. The gold standard and most reliable option for hallux varus deformity is first MTPJ fusion. However, it results in stiffness and loss of joint function and is reserved for arthritic and stiff first MTPJ. Flexible iatrogenic hallux varus is corrected by optimally anatomic ligament reconstruction. The purpose of this Technical Note is to describe the details of arthroscopically assisted reconstruction of lateral metatarsosesamoid suspensory and lateral metatarsophalangeal collateral ligaments in management of iatrogenic hallux varus deformity. We reconstruct the lateral metatarsosesamoid suspensory ligament to restore the rotational stability of the first MTPJ in hallux varus deformity. This together with reconstruction of the lateral metatarsophalangeal collateral ligament anatomically corrects both the medial deviation and rotation deformity of the great toe.

An Ultrasonic Ridge-Tracking Method Based on Limiter Sliding Window Filter and Fuzzy Pure Pursuit Control for Ridge Transplanter

There are various types of fruits and vegetables that need to be planted on ridges. In order to allow for seedlings with a certain row space and seedling space, the ridge transplanter should be able to track along the ridge. Therefore, an ultrasonic ridge-tracking method and system were developed to let the ridge transplanter track the ridge accurately. The ultrasonic ridge-tracking method mainly contains a limiter sliding window filtering algorithm and a fuzzy look-ahead distance decision model. The limiter sliding window filtering algorithm was proposed to filter the abnormal measuring results to avoid disoperation of the steering mechanism. Moreover, the fuzzy look-ahead distance decision model was proposed to determine the optimal look-ahead distance in order to obtain a desirable tracking performance. Additionally, a comparison experiment of the proposed ultrasonic ridge-tracking method and the universal pure pursuit method was conducted. The experimental results show that the greatest mean absolute errors of the lateral deviations of the ultrasonic ridge-tracking method and universal pure pursuit were 10.56 mm and 13.11 mm. The greatest maximum absolute errors of the lateral deviations of the ultrasonic ridge-tracking method and universal pure pursuit were 18.87 mm and 23.23 mm. In addition, the greatest root mean square error of the lateral deviation of the ultrasonic ridge-tracking method and the universal pure pursuit method were 13.52 mm and 15.66 mm. According to the ridge-tracking performance of the proposed ultrasonic ridge-tracking method, it can be used in practical transplanting conditions. Moreover, in other fields, robots or intelligent machinery can also apply the proposed ultrasonic ridge-tracking method to track objects similar to ridges.

Tortícolis en lactante asociada a infección por citomegalovirus: ¿es un hallazgo casual?

Benign paroxysmal torticollis is a non-epileptic paroxysmal disorder that begins in the first year of life. It is characterized by recurrent episodes of head tilting lasting from hours to days. These episodes can be accompanied by irritability, pallor, nausea, vomiting, and ataxia, while the patient remains asymptomatic between episodes. We present the case of an infant with several episodes of lateral neck deviation lasting a few days each, without other accompanying symptoms, and asymptomatic between episodes. Magnetic resonance imaging was performed, ruling out a space-occupying process but revealing bilateral cervical adenopathy. Further testing detected positive IgG and IgM for Cytomegalovirus, leading to a diagnosis of Cytomegalovirus infection and benign paroxysmal torticollis. Both conditions are currently resolving and appear to be unrelated.

Factors Affecting Rear-End Collisions in Underground Road Junctions Using VISSIM

Due to urban overcrowding, available land is limited and traffic congestion has increased. Underground roads are being built to mitigate traffic congestion as an alternative. Studies associated with underground roads are needed because these roads are dark and closed and have a high risk of accidents compared to surface roads. In particular, there is limited study on junctions that connect two or more underground roads. In this study, an underground road network including junctions was constructed to analyze the factors behind rear-end collisions at underground road connections. To reflect the driving behavior on underground roads, the scenario analysis was conducted by applying the speed distribution of underground roads in Korea. The results of the analysis showed that variables such as acceleration standard deviation and lateral position standard deviation are crucial for accidents on underground roads. Thus, this study can be used as a basis for traffic management and safety improvement in the operation of underground road junctions in the future.

Efficient vehicle lateral safety analysis based on Multi-Kriging metamodels: Autonomous trucks under different lateral control modes during being overtaken

Different lateral control modes for autonomous trucks have been proposed in the past to improve road sustainability. To evaluate the lateral reliability and risk of autonomous trucks under different lateral control modes, especially in windy conditions and during overtaking, this study proposes a high-precision, efficient method based on Multi-Kriging (MK) metamodeling. Compared to Support Vector Regression (SVR), widely used in vehicle safety studies, the MK method builds Kriging metamodels for all potential deviation crashes of autonomous trucks, significantly reducing computational costs while ensuring accuracy. Additionally, instead of using the maximum lateral deviation as a dynamic risk indicator, this study innovatively suggests using the distance between the autonomous truck and the lane line after the maximum lateral deviation occurs. Considering the vehicle and environmental characteristics, the MK method is used to calculate the probability of a crash and the associated risk at various lateral positions of the autonomous truck, quantifying the crash probability and risk values under different lateral control modes. Furthermore, the study investigates the influence of the standard deviation of the normal distribution on the crash probability and risk values of autonomous trucks, providing valuable insights for future research on road sustainability and safety under autonomous driving conditions.

Accuracy of Cervical Pedicle Screw Insertion With and Without a Navigation-Linked High-Speed Drill: A Retrospective Clinical Study.

Cervical pedicle screw (CPS) fixation provides high stability but poses a risk of nerve and vascular injury. Although useful for reducing CPS deviation rates, navigation systems cannot completely eliminate deviation. This study aimed to compare two methods for creating insertion paths, one using a navigation-linked high-speed drill (NAVI drill) and the other using conventional manual probing. Our study comprised 104 patients with 509 CPSs at the C3-6 level who were treated at our institution between 2017 and 2023. CPS deviations were graded according to the Neo classification system, and the deviation direction (medial, lateral, cranial, or caudal) was assessed. Complications associated with CPS deviation were also investigated. We compared cases that used the NAVI drill (Group M) with those that used manual probing (Group N). Group M included 45 cases (252 screws), and Group N included 59 cases (257 screws). The CPS deviation rate was grade 1 or higher in 14.7% and 17.1% of cases in Groups M and N, respectively (p = 0.469). It was grade 2 or higher in 1.2% and 4.3% of cases in Groups M and N, respectively (p = 0.222). The medial, lateral, caudal, and cranial deviation direction rates were 56.8%, 2.7%, 40.5%, and 0% in Group M and 13.6%, 72.7%, 11.4%, and2.3% in Group N, respectively (p < 0.001). In one case in Group N, a grade 3 lateral deviation resulted in vertebral artery injury (VAI). The use of the NAVI drill was associated with a slightly lower, albeit insignificant, CPS deviation rate. However, it significantly lowered the proportion of lateral deviations. Therefore, the NAVI drill is a useful tool for preventing VAI.

Research on dynamic constraint mechanism and motion control of intelligent vehicles based on preview distance optimization under complex road conditions

Aiming at the coupling and conflict issues between intelligent vehicle dynamics characteristics and path tracking system under complex road conditions, this paper investigates the dynamics constraint mechanism and motion control of intelligent vehicles, and proposes an intelligent vehicle lateral–vertical cooperative control method based on optimized preview distance. To begin with, an intelligent vehicle path tracking control system based on expected yaw velocity has been designed by establishing a three-degree-of-freedom dynamic model for intelligent vehicle. Then, we analyzed the mechanism by which changes in vehicle speed, road curvature, and preview distance affect the accuracy of vehicle path tracking and handling stability. Considering the “human-vehicle-road” system in intelligent transportation systems, critical values for collision and instability were set. Furthermore, we designed a proactive optimization method for preview distance under different working conditions, using an optimization algorithm to improve path tracking accuracy while ensuring vehicle stability, based on the lateral displacement deviation and lateral orientation deviation representing the accuracy of path tracking, as well as the lateral acceleration representing handling stability. Finally, hardware-in-the-loop platform test was conducted. The simulation and test results show that the optimized path tracking algorithm reduces lateral deviation to as low as 0.05 m, and the stability constraint control in the algorithm can be triggered promptly even under extreme conditions.

Using distributed simulations to investigate driver-pedestrian interactions and kinematic cues: Implications for automated vehicle behaviour and communication

As we move towards a future with Automated Vehicles (AVs) incorporated in the current traffic system, it is crucial to understand driver-pedestrian interaction, in order to enhance AV design and optimization. Previous research in this area, which has primarily used naturalistic observations or single-actor virtual reality simulations, has been limited by its inability to draw causal conclusions, also due to a lack of real human–human interactions. Our study addresses these limitations by employing a high-fidelity distributed simulation setup that links drivers in a motion-based simulator with pedestrians in a CAVE-based environment. This method allows for the examination of real-time and reciprocal interactions across a range of road-crossing scenarios. Using thirty-two pairs of drivers and pedestrians, we investigated how different factors, such as the presence of zebra crossings and varying time gaps of the approaching vehicle, influence driver behaviour and pedestrian crossing decisions. The effect of drivers’ control of the vehicle during such crossings (e.g., braking behaviour and lateral deviation) on pedestrians’ crossing decisions were also analysed. We found that the distribution of drivers’ average deceleration values were bimodal, where drivers either markedly yielded to pedestrians, or continued in their path, with very few instances of intermediate behaviour. We also found that pedestrian decisions were seemingly influenced by the different braking strategies adopted by the driver, with pedestrians crossing before the vehicles in response to soft and early, or late and hard braking, while late and soft braking often resulted in the vehicle passing first. We also observed a slight lateral movement of the vehicle away from pedestrians when drivers were not yielding, but more of a lateral deviation towards them when yielding. This may be because drivers subconsciously transfer their walking interaction habits to their driving behaviour, to avoid a collision with pedestrians. Finally, our results showed a stronger influence of these kinematic cues on pedestrian crossing decisions, when compared to zebra crossings. As well as highlighting the value of a novel approach for investigating vehicle–pedestrian interactions, this study illustrates how vehicle cues can assist pedestrian decisions, adding new knowledge in the development of human-like behaviour for future AVs.

Vision-based trajectory generation and tracking algorithm for maneuvering of a paddy field robot

In this study, we propose a novel visual-based autonomous trajectory-tracking control method for steering a wheeled robot following the lines of crop row in paddy field. A rice crop rows detection method, based on the region growth sequential clustering − random sample consensus (RANSAC) algorithm, is developed to generate trajectory. Concurrently, a dynamics predictive controller is employed to compute the command for the desired steering angle. The controller leverages a model that incorporates slip dynamics and operates on a low power consumption industrial computer. Experimental results show that the developed algorithm can successfully obtain the correct trajectory in more than 96.25 % of the cases, with the angle error consistently below 3°. Furthermore, the single-image processing time is notably swift at 13.98 ms, underscoring the commendable adaptability and real-time performance of the proposed methodology. During movement in the paddy field, the robot exhibits maximum lateral deviations of 4.55 cm, 5.65 cm, and 6.41 cm at speeds of 0.3 m/s, 0.6 m/s, and 0.9 m/s, respectively, accompanied by corresponding heading angle errors of 4.59°, 5.63°, and 7.39°. Notably, while adeptly tracking rice crop rows at all three speeds, the robot consistently maintains a maximum lateral error below one-fourth of the inter-row spacing of rice planting. This study assumes significance in enhancing the stability of ground-traversing agricultural robots, serving as a valuable reference for advancing the research and development of intelligent and efficient agricultural robotic systems.