Trajectory Measurements Research Articles

FEATURES OF RESTORING MEASUREMENT VALUES OF THE DOPPLER RADAR SYSTEM MFTR-2100/40 DURING ARMAMENT AND MILITARY EQUIPMENT TESTING

During the registration and processing of measurement information obtained by the MFTR-2100/40 radar system, there is a probability of missing values in the trajectory measurement data. Experience with the radar system indicates a high sensitivity of the angular channels to the propagation of the radar signal in the real atmosphere. As a result of these errors, object tracking may be lost over a certain period, causing periodic delays in data registration, necessitating the filling or restoring of missing values with acceptable accuracy. The built-in algorithms and mathematical methods of the WinTrack specialized software (SS) allow for the interpolation and extrapolation of the trajectory measurement data of the MFTR-2100/40 radar system for visual display and plotting of tracks, including ranges with missing values. However, the functional capabilities of the WinTrack SS are not designed for full and accurate restoration of missing values. Additionally, the limited tools of the WinTrack SS necessitate finding alternatives in other software to ensure the reliability of the restored results. Trajectory measurement data is a large dataset, so selecting the right method for filling in missing values is crucial to maintaining a low percentage of deviations in the obtained results. This publication examines the functional capabilities of the WinTrack SS that allow for the restoration of missing trajectory measurement values. The approximation of measured trajectory data values in the WinTrack SS enables partial filling of missing values upon export, but not for all data types. An algorithm for the process of restoring missing values in trajectory measurement data arrays is provided.

A three-dimensional trajectory measurement system for quasi-one-dimensional high-speed moving objects

Abstract The three-dimensional (3D) trajectory measurement of a quasi–one-dimensional (quasi-1D) high-speed moving object often cannot achieve the optimizations of both the measurement range and the object’s resolution at the same time. In this paper, a 3D trajectory measurement system for quasi-1D high-speed moving objects is proposed. The system was composed of a single camera and a galvo mirror. The posture of the virtual camera is changed by adjusting the angle of the galvo mirror, thereby achieving the tracking and imaging of a quasi-1D high-speed moving object. For a background with complex textures, a measurement method based on the reconstructed homography matrix is proposed. The extrinsic matrix of the virtual camera is estimated based on the feature points on the background, and the equation of the object trajectory’s plane is estimated based on the feature points on the object. Then, by combining the extrinsic matrix and the equation of the plane, a new homography matrix is reconstructed, realizing the measurement of the 3D coordinates of the object. For a background with weak textures, a method based on the deflection angle of the galvo mirror is proposed for the calibration of the extrinsic matrix of the virtual camera. This method can calculate the extrinsic matrix of the virtual camera based on the distance from the camera to the center point of the galvo mirror and the deflection angle of the galvo mirror. The experimental results show that the proposed system is able to increase the field of view by 430%. For complex-texture backgrounds, the relative error of the system is 0.79%, and for weak-texture backgrounds, the relative error is 4.65%.

On the correction of spiral trajectories on a preclinical MRI scanner with a high-performance gradient insert.

This study aimed to examine different trajectory correction methods for spiral imaging on a preclinical scanner with high-performance gradients with respect to image quality in a phantom and in vivo. The gold standard method of measuring the trajectories in a separate experiment is compared to an isotropic delay-correction, a correction using the gradient system transfer function (GSTF), and a combination of the two. Three different spiral trajectories, with 96, 16, and three interleaves, are considered. The best image quality is consistently achieved when determining the trajectory in a separate phantom measurement. However, especially for the spiral with 96 interleaves, the other correction methods lead to almost comparable results. Remaining imperfections in the corrected gradient waveforms and trajectories are attributed to asymmetrically occurring undulations in the actual, generated gradients, suggesting that the underlying assumption of linearity is violated. In conclusion, images of sufficient quality can be acquired on preclinical small-animal scannersusing spiral k-space trajectories without the need to carry out separate trajectory measurements each time. Depending on the trajectory, a simple isotropic delay-correction or a GSTF-based correction can provide images of similar quality.

Comparative analysis of upper body kinematics in stroke, Parkinson's disease, and healthy subjects: An observational study using IMU-based targeted box and block test

BackgroundThe Box and Block Test (BBT) is an essential and widely used test in rehabilitation for the assessment of gross unilateral manual dexterity. Although it is a valid, simple, and ecological instrument, it does not provide a quantitative measure of the upper limb trajectories during the test. Research questionThe study introduces a new motion-capture-based method (using ecological Inertial Measurement Units - IMUs) to evaluate upper body kinematics while performing a targeted version of BBT (tBBT). MethodsThis observational study compares data from 35 healthy subjects, 35 subjects with Parkinson’s disease, and 35 post-stroke individuals to evaluate upper limb kinematics during tBBT quantitatively. Seven IMUs were placed on the trunk, head, and upper limb of each subject. The joint angles and kinematic scores were calculated and analyzed. Motor task execution time and kinematic scores were statistically correlated with clinical assessment measures. Kruskal-Wallis between groups test and Dunn-Bonferroni post-hoc were used. ResultsThe statistics revealed significant differences (p<0.05) among the three groups. The analyzed joint angles highlight various compensatory strategies in neurological subjects, such as using the trunk to complete a motor task instead of the shoulder and using the wrist instead of the elbow, along with differences in movement fluidity (DimensionLess-Jerk, p<0.05). A positive correlation was found between kinematics and the Fugl-Meyer Assessment-Upper Limb (r=0.7344; p<0.01), and a negative correlation between kinematics and the Unified Parkinson's Disease Rating Scale (r=-0.5286; p<0.01). SignificanceThe quantitative assessments of joint kinematics correlated to clinical assessments could guarantee a new method of assessment of the upper limb in subjects with motor deficits. This would allow to capture new insight into the characteristics of the subject’s disability, with implications for the choice of a personalized rehabilitation treatment focused on the motor recovery of the upper limb.

Finger Multi-Joint Trajectory Measurement and Kinematics Analysis Based on Machine Vision

A method for measuring multi-joint finger trajectories is proposed using MediaPipe. In this method, a high-speed camera is used to record finger movements. Subsequently, the recorded finger movement data are input into MediaPipe, where the system automatically extracts the coordinate data of the key points in the finger movements. From this, we obtain data pertaining to the trajectory of the finger movements. In order to verify the accuracy and effectiveness of this experimental method, we compared it with the DH method and the Artificial keypoint alignment method in terms of metrics such as MAPE (Mean Absolute Percentage Error), maximum distance error, and the time taken to process 500 images. The results demonstrated that our method can detect multiple finger joints in a natural, efficient, and accurate manner. Then, we measured posture for three selected hand movements. We determined the position coordinates of the joints and calculated the angular acceleration of the joint rotation. We observed that the angular acceleration can fluctuate significantly over a very short period of time (less than 100 ms), in some cases increasing to more than ten times the initial acceleration. This finding underscores the complexity of finger joint movements. This study can provide support and reference for the design of finger rehabilitation robots and dexterous hands.

基于扫描上下文和 NDT-ICP 融合方案的果园同步定位与绘图方法研究

Simultaneous localization and mapping (SLAM) is one of the key technologies for agricultural robots to build maps and localize in complex orchard environments and realize unmanned autonomous operations. Due to the complexity of the orchard environment, the single canopy feature and the diffuse reflection of light caused by the leaves, etc., the map construction process of the orchard environment leads to mismatch and increases the cumulative error of the map construction. Aiming at the above problems, this paper propose a navigation map construction method for orchard environment based on the fusion of Scan Context and NDT-ICP. The method firstly searches the Ring key quickly to get the candidate frames, and scores the similarity between the candidate frames and the current frame, and effectively detects the loopbacks by two-stage searching algorithm to reduce the false matches in the map of orchard environment. Meanwhile, a point cloud alignment method based on the fusion of normal distribution transform coarse alignment and iterative nearest point exact alignment is used to reduce the cumulative error of the orchard environment map. The results show that the improved algorithm compensates the drift of the point cloud map with higher mapping accuracy, better real-time performance, lower resource utilization, higher overlap between the trajectory estimation and the real trajectory, smoother loops, and a 4% reduction in CPU occupancy. In the complex orchard environment, the root mean square error and standard deviation of the trajectories of this paper's algorithm are 0.57 m and 0.19 m, which are 68% and 83% higher than those of the loop detection algorithms in the Lightweight Ground Optimized Lidar Trajectory Measurement and Multivariate Terrain Mapping (LeGO-LOAM), respectively. Accurate map construction and low drift pose estimation can be performed.The research algorithm effectively reduces the influence of mis-matching and large cumulative error in the process of map construction in the orchard environment, meets the demand for high-precision environmental mapping in the orchard environment, and provides technical support for promoting unmanned operation in the orchard environment.

Kinetic Trajectories of Glucose Uptake in Single Cancer Cells Reveal a Drug-Induced Cell-State Change Within Hours of Drug Treatment.

The development of drug resistance is a nearly universal phenomenon in patients with glioblastoma multiforme (GBM) brain tumors. Upon treatment, GBM cancer cells may initially undergo a drug-induced cell-state change to a drug-tolerant, slow-cycling state. The kinetics of that process are not well understood, in part due to the heterogeneity of GBM tumors and tumor models, which can confound the interpretation of kinetic data. Here, we resolve drug-adaptation kinetics in a patient-derived in vitro GBM tumor model characterized by the epithelial growth factor receptor (EGFR) variant(v)III oncogene treated with an EGFR inhibitor. We use radiolabeled 18F-fluorodeoxyglucose (FDG) to monitor the glucose uptake trajectories of single GBM cancer cells over a 12 h period of drug treatment. Autocorrelation analysis of the single-cell glucose uptake trajectories reveals evidence of a drug-induced cell-state change from a high- to low-glycolytic phenotype after 5-7 h of drug treatment. Information theoretic analysis of a bulk transcriptome kinetic series of the GBM tumor model delineated the underlying molecular mechanisms driving the cellular state change, including a shift from a stem-like mesenchymal state to a more differentiated, slow-cycling astrocyte-like state. Our results demonstrate that complex drug-induced cancer cell-state changes of cancer cells can be captured via measurements of single cell metabolic trajectories and reveal the extremely facile nature of drug adaptation.

Annular optical trapping of metallic nanoparticles using the azimuthally polarized beam.

The unique physical and chemical properties make metallic nanoparticles promising for broad applications in many fields. Exploring the dynamics of metallic nanoparticles in optical traps is crucial for exploiting optical tweezers to advance the applications of metallic particles. In this paper, we present a detailed study of the annular optical trapping of gold nanoparticles with azimuthal polarization. Theoretical analysis based on the T-matrix method shows that the gold nanoparticles experience optical forces pointing to the equilibrium position along the radial direction, while there is no force along the azimuthal direction at this equilibrium position. Therefore, a tightly focused azimuthally polarized beam captures gold nanoparticles in an annular region. Experimental measurements of the motion trajectory of the confined gold nanoparticles reveal a donut profile consistent with the theoretical predictions. Our work reported in this paper is expected to deepen our understanding of the interactions between metallic nanoparticles and light and promote the application of metallic nanoparticles.

Blowing in the dark matter wind

Interactions between dark matter and ordinary matter will transfer momentum, and therefore give rise to a force on ordinary matter due to the dark matter ‘wind.’ We show that this force can be maximal in a realistic model of dark matter, meaning that an order-1 fraction of the dark matter momentum incident on a target of ordinary matter is reflected. The model consists of light (mϕ ≲ eV) scalar dark matter with an effective interaction ϕ2ψ¯ψ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\phi}^2\\overline{\\psi}\\psi $$\\end{document}, where ψ is an electron or nucleon field. If the coupling is repulsive and sufficiently strong, the field ϕ is excluded from ordinary matter, analogous to the Meissner effect for photons in a superconductor. We show that there is a large region of parameter space that is compatible with existing constraints, where the force is large enough to be detected by existing force probes, such as satellite tests of the equivalence principle and torsion balance experiments. However, shielding of the dark matter by ordinary matter prevents existing experiments from being sensitive to the dark matter force. We show that precise measurements of spacecraft trajectories proposed to test long distance modifications of gravity are sensitive to this force for a wide range of parameters.

Application of locally regularized extremal shift to the problem of realization of a prescribed motion

Abstract A controlled system of differential equations under the action of an unknown disturbance is considered. The problem discussed in the paper consists in constructing algorithms for forming a control that provides the realization of a prescribed motion for any admissible disturbance. Namely these algorithms should provide the closeness in the metric of the space of differentiable functions of a phase trajectory of a given controlled system and some etalon trajectory of an analogous system functioning when any outer actions are absent. As the space of admissible disturbances, we take the space of measurable square integrable (with respect to the Euclidean norm) functions. The cases of inaccurate measurements of phase trajectories of both systems at all times and at discrete times are under study. Two computer oriented algorithms for solving the problem are designed. The algorithms are based on the (well-known in the theory of guaranteed control) method of extremal shift. In the process, its local (at each time of control correction) regularization is performed by the method of smoothing functional (the Tikhonov method). In addition, estimates for algorithm’s convergence rate are presented.

Exploring the role of anticipatory postural adjustment duration within APA2 subphase as a potential mediator between clinical disease severity and fall risk in Parkinson's disease.

People with Parkinson's Disease (PD) often show reduced anticipatory postural adjustments (APAs) before voluntary steps, impacting their stability. The specific subphase within the APA stage contributing significantly to fall risk remains unclear. We analyzed center of pressure (CoP) trajectory parameters, including duration, length, and velocity, throughout gait initiation. This examination encompassed both the postural phase, referred to as anticipatory postural adjustment (APA) (APA1, APA2a, APA2b), and the subsequent locomotor phases (LOC). Participants were instructed to initiate a step and then stop (initiating a single step). Furthermore, we conducted assessments of clinical disease severity using the Unified Parkinson's Disease Rating Scale (UPDRS) and evaluated fall risk using Tinetti gait and balance scores during off-medication periods. Freezing of gait (FOG) was observed in 18 out of 110 participants during the measurement of CoP trajectories. The Ramer-Douglas-Peucker algorithm successfully identified CoP displacement trajectories in 105 participants (95.5%), while the remaining 5 cases could not be identified due to FOG. Tinetti balance and gait score showed significant associations with levodopa equivalent daily dose, UPDRS total score, disease duration, duration (s) in APA2a (s) and LOC (s), length in APA1 (cm) and APA2b (cm), mediolateral velocity in APA1 (X) (cm/s), APA2a (X) (cm/s), APA2b (X) (cm/s) and LOC (X) (cm/s), and anterior-posterior velocity in APA2a (Z) (cm/s) and APA2b (Z) (cm/s). Multiple linear regression revealed that only duration (s) in APA2a and UPDRS total score was independently associated with Tinetti gait and balance score. Further mediation analysis showed that the duration (s) in APA2a served as a mediator between UPDRS total score and Tinetti balance and gait score (Sobel test, p = 0.047). APA2 subphase duration mediates the link between disease severity and fall risk in PD, suggesting that longer APA2a duration may indicate reduced control during gait initiation, thereby increasing fall risk.

Indenting a thick gel with a solid spherical inclusion

A spherical inclusion is embedded in a soft gel block. A vertical force is applied on the gel surface by means of a spherical indenter. The loading axis is not aligned with the inclusion but placed at a horizontal offset displacement from the inclusion. The measurement of indentation force and inclusion trajectory are compared to the computational results from two-dimensional (2D) Finite Element Analysis (FEA) simulations. A discernible instability emerges when the indentation reaches a critical depth, in accordance with the Southwell instability theory. The three-dimensional (3D) trajectory shows distinct features that were previously not captured by the 2D FEA simulations.

Optimization of Radial Jet drilling for hard formations present in deep geothermal wells

Creating controllable fractures in geothermal wells with deep crystal structures is challenging due to rock strength. Radial Jet Drilling (RJD), which creates micro holes through rock, could stimulate these wells. However, it is challenging to implement RJD when drilling hard magmatic formations that are difficult to jet. Several factors influence RJD's effectiveness, including the jetting bit design, fluid properties, circulation rate, injection pressure, stress state in the formation, borehole pressure, and temperature. These factors determine RJD's performance parameters, such as jet stagnation pressure, jet hydraulic power, and maximum lateral hole length. This study aims to develop a generalized model for optimizing RJD's application in geothermal wells with hard formations. A unique feature of the study is the coupling of a hydraulic model with jetting criteria (threshold conditions) developed for evaluating jet-rock interactions under high-pressure conditions.This study introduces an advanced hydraulic model for RJD application, distinct from classical models that rely on field measurements and typically analyze only horizontally oriented nozzles. Our model encompasses a broader scope of operational and design parameters, facilitating the optimization of RJD in challenging geothermal environments without necessitating direct field data. Key performance metrics such as jet stagnation pressure, jet hydraulic power, and maximum lateral hole length are evaluated, emphasizing the critical role of each in overcoming the inherent challenges of hard rock formations, which require stagnation pressure of more than 100 MPa and jet hydraulic power of more than 5.2 KW. The findings reveal that achieving these conditions requires carefully balancing injection pressure, fluid flow rate, and equipment capabilities. Notably, the model underscores the necessity for robust equipment capable of high-pressure operations, including flexible tubing, compact downhole pressure intensifiers, and more advanced inclination and azimuth detection systems for lateral hole trajectory measurement and control.According to the new model, the RJD technique can be optimized by varying the densities of flexible tubes, the inclination angles of the lateral hole, and the number of back-jetting (BJ) nozzles. Results demonstrate that using an aluminum tube or adjusting the lateral hole to an inclination of 74° can enhance the maximum lateral hole length (MHL) by up to four times for the baseline case. Furthermore, increasing BJ nozzles from four to six can lead to an eightfold improvement in the MHL for the baseline scenario. Overall, the study enhances our understanding of RJD's potential in geothermal well stimulation. It offers a comprehensive framework for effectively implementing it in hard rock settings, creating a scenario for more efficient and economically viable geothermal energy production.

Association between trajectories of adherence to endocrine therapy and risk of treated breast cancer recurrence among US nonmetastatic breast cancer survivors.

Endocrine therapy is the mainstay treatment for breast cancer (BC) to reduce BC recurrence risk. During the first year of endocrine therapy use, nearly 30% of BC survivors are nonadherent, which may increase BC recurrence risk. This study is to examine the association between endocrine therapy adherence trajectories and BC recurrence risk in nonmetastatic BC survivors. This retrospective cohort study included Medicare beneficiaries in the United States (US) with incident nonmetastatic BC followed by endocrine therapy initiation in 2010-2019 US Surveillance, Epidemiology, and End Results linked Medicare data. We calculated monthly fill-based proportion of days covered in the first year of endocrine therapy. We applied group-based trajectory models to identify distinct endocrine therapy adherence patterns. After the end of the first-year endocrine therapy trajectory measurement period, we estimated the risk of time to first treated BC recurrence within 4 years using Cox proportional hazards models. We identified 5 trajectories of adherence to endocrine therapy in BC Stages 0-I subgroup (n = 28,042) and in Stages II-III subgroup (n = 7781). A trajectory of discontinuation before 6 months accounted for 7.0% in Stages 0-I and 5.8% in Stages II-III subgroups, and this trajectory was associated with an increased treated BC recurrence risk compared to nearly perfect adherence (Stages 0-I: adjusted hazard [aHR] = 1.84, 95% CI = 1.46-2.33; Stages II-III: aHR = 1.38, 95% CI = 1.07-1.77). Nearly 7% of BC survivors who discontinued before completing 6 months of treatment was associated with an increased treated BC recurrence risk compared to those with nearly perfect adherence among Medicare nonmetastatic BC survivors.

Consistent anatomical relationships of pedicle, lamina, and superior articulating process in severe idiopathic scoliosis allow for safe freehand pedicle screw placement: A proof-of-concept technical study.

Transpedicular screw placement has superior pullout strength compared to alternative forms of spinal fusion and is often performed in deformity correction surgery with navigation for optimal accuracy and reliability. Freehand technique for pedicle screws minimizes operation time and radiation exposure without fluoroscopy but is not widely adopted given the challenge of difficult anatomical corridors and accurate placement, especially in idiopathic scoliosis and advanced deformity. We used a computer-generated model to assess a proof-of-concept and anatomical feasibility of a freehand screw technique in severe scoliosis. Three-dimensional (3D) reconstructions of vertebra from a sample of two male patients with severe idiopathic scoliosis deformity (1 thoracic and 1 lumbar) with Cobb angles of 100° were used for planned placement of 17 levels of thoracolumbar (6.5 mm × 45 mm) pedicle screws. 3D reconstruction of each vertebra was created and measurements of screw entries and trajectories were reproduced with a 3D slicer software image computing platform. Accurate transpedicular screw placement is possible with anatomical landmarks based on the 3D reconstructed vertebral levels. A series of 5 figures were assembled to demonstrate sagittal, coronal, and axial planes and key anatomical landmarks and trajectories of thoracic and lumbar freehand pedicle screws in severe idiopathic scoliosis. Anatomical landmarks for freehand transpedicular screw placement (between pedicle, lamina, and superior articulating process) are constant and reliable in severe idiopathic scoliosis as evidenced by 3D computer modeling. Preoperative computed tomography modeling may assist appropriate screw entry and trajectory based on anatomical landmarks for spine surgeons, and guide freehand technique for screw placement in adolescent idiopathic scoliosis.

Neighborhood eviction trajectories and odds of moderate and serious psychological distress during pregnancy among African American women.

African American mothers are unjustly burdened by both residential evictions and psychological distress. We quantified associations between trajectories of neighborhood evictions over time and the odds of moderate and serious psychological distress (MPD and SPD, respectively) during pregnancy among African American women. We linked publicly available data on neighborhood eviction filing and judgment rates to preconception and during-pregnancy addresses from the Life-course Influences on Fetal Environments (LIFE) Study (2009-2011; n=808). Multinomial logistic regression-estimated odds of MPD and SPD during pregnancy that were associated with eviction filing and judgment rate trajectories incorporating preconception and during-pregnancy addresses (each categorized as low, medium, or high, with two 9-category trajectory measures). Psychological distress was measured with the Kessler Psychological Distress Scale (K6) (K6 scores 5-12=MPD, andK6 scores ≥13=SPD). MPD was reported in 60% of the sample and SPD in 8%. In adjusted models, higher neighborhood eviction filing and judgment rates, as compared with low/low rates, during the preconception and pregnancy periods were associated with 2- to 4-fold higher odds of both MPD and SPD during pregnancy among African American women. In future studies, researchers should identify mechanisms of these findings to inform timely community-based interventions and effective policy solutions to ensure the basic human right to housing for all. This article is part of a Special Collection on Mental Health.

Creation of a Prototype Cochlear Training Model.

Creation of a novel 3D-printed physical cochlear model that demonstrated the feasibility of creating the model, and impact of a Graphical User Interface (GUI) system on training insertion metrics. Feasibility study with a pilot prospective data collection. Tertiary academic center. The study was IRB exempt. Five resident trainees (PGY1-PGY5) practiced electrode insertions in cadaveric temporal bones before using the simulator. Nine students were educated on how to hold the electrodes and position them, and then allowed to use the simulator. All trainees were instructed that slower insertions were favorable. One cochlear implant (CI) surgeon used the simulator. The GUI captured the real video feed, but also provided distance, trajectory, and velocity measurements. The program is designed to plot the real-time depth of insertion and speed of insertion of the electrode; the user is also provided real-time occurrence of any kinks and back-outs. A total of 14 trainees and 1 CI surgeon inserted the electrode at least 5 times without the use of the GUI (before) and then at least 5 times with the use of the GUI (after). Average Speed before and after (100.84 and 53.23 mm/s); Average minimum speed before and after (59.34 and 9.65 mm/s); and Average maximum speed before and after (416 and 285.81 mm/s). Statistically significant improvements were noted in all the measured speeds of insertion (P < .001). The other variables improved but not to a statistical significance. Real-time training using the 3D-printed model and GUI for cochlear implantation can help improve surgical resident training and comfort levels with electrode insertion for surgical trainees. The advantage of this model is that surgeons/trainees can use it as many times as they like, as the whole set-up is easy, economical, and reusable. The real time graphical user interface enhances training and retention of the practiced skills.

Kinematic Performance of a Customizable Single Degree-of-Freedom Gait Trainer for Cost-Effective Therapy Aimed at Neuromuscular Impairments

Abstract A majority of robotic gait trainers to facilitate physical therapy for gait rehabilitation in humans are based on multidegree-of-freedom exoskeleton-based systems with sophisticated electro-mechanical hardware and software, and consequently remain inaccessible to vast sections of the populations around the world. This study seeks to advance the development of a single degree-of-freedom (DOF) gait trainer for gait therapy for individuals with neuromuscular impairments. The goal is to offer a cost-effective, accessible solution to cater to the global need for gait rehabilitation. We build upon the previous gait trainer design based on Jansen mechanism and provide an in-depth analysis and experimental validation of its kinematic performance. The device's performance is also tested and successfully demonstrated through trials involving two healthy individuals to examine its kinematic behavior under human-induced load conditions. The gait trainer demonstrates satisfactory performance under both no load conditions and a 2 kg load, exhibiting an area difference of 1% and 7%, respectively. However, when subjected to a 5 kg loading condition, a significant area difference of 27% is observed, primarily attributed to the cantilever loading at the driving shaft. A method to adjust link lengths based on specific human gait trajectories is proposed and validated. Additionally, a cost-effective tool for ankle trajectory measurement is introduced to establish a ground truth. The study demonstrates the potential of an affordable, single DOF gait trainer in facilitating high-volume therapy for those with walking disorders. This research represents a step toward making gait therapy more accessible worldwide.

Prototype of Check the Class Individually by Making Our Rounds in the Classroom Trajectory Measurement System Using Laser Range Sensor

Prototype of Check the Class Individually by Making Our Rounds in the Classroom Trajectory Measurement System Using Laser Range Sensor

Analysis of techniques and technologies for processing trajectory measurements

The article discusses the uncertainty factors of processing trajectory measurements. The purpose of the work: to consider uncertainty factors, to analyze methods for solving poorly formalized problems, as well as the methodology for solving them when processing trajectory measurements using artificial intelligence and expert systems. An important uncertainty factor in the development of methods for processing trajectory measurements is the fuzziness or ambiguity associated with a subset of natural language. Considering the tasks at various stages of the development of methods for processing trajectory measurements as decision-making tasks, it is advisable to indicate the uncertainty factors that occur in various situations when solving these tasks. These include vagueness, ambiguity, and uncertainty: arising from the description of resources allocated for modeling; arising in the case when the available numerical information does not allow to find solutions by formal methods, but nevertheless, there are such solutions; arising in the early stages of processing, when there are a number of alternative options; arising from the interpretation of the results of computational experiments; arising in the case when, despite the possibility of using precise mathematical relations to solve selection problems, it is convenient for experts to use informal methods that reduce the time required to solve the required tasks. The analysis of methods for solving problems of processing trajectory measurements is carried out. A new methodology is presented, the essence of which is to change the traditional scheme of formalization of the tasks of the subject area of interest to engineers, in cases where the use of the traditional scheme is impossible for some reason. A methodology for solving poorly formalized problems is presented, as well as expert systems for processing trajectory data.