Body Frame Research Articles

A review of path following control strategies for autonomous robotic vehicles: Theory, simulations, and experiments

AbstractThis article presents an in‐depth review of path following control strategies that are applicable to a wide range class of marine, ground, and aerial autonomous robotic vehicles. From a control system standpoint, path following can be formulated as the problem of stabilizing a path following error system that describes the dynamics of position and possibly orientation errors of a vehicle with respect to a path, with the errors defined in an appropriate reference frame. In spite of the large variety of path following methods described in the literature we show that, in principle, most of them can be categorized in two groups: stabilization of the path following error system expressed either in the vehicle's body frame or in a frame attached to a “reference point” moving along the path, such as a Frenet‐Serret (F‐S) frame or a Parallel Transport (P‐T) frame. With this observation, we provide a unified formulation that is simple but general enough to cover many methods available in the literature. We then discuss the advantages and disadvantages of each method, comparing them from the design and implementation standpoint. We further show experimental results of the path following methods obtained from field trials testing with under‐actuated and over‐actuated autonomous marine vehicles. In addition, we introduce open‐source Matlab and Gazebo/ROS simulation toolboxes that are helpful in testing path following methods before their integration in the combined guidance, navigation, and control systems of autonomous vehicles.

Analysis and compensation of residual gyro drifts on azimuth alignment accuracy in the RINS

The rotational inertial navigation system (INS) uses rotational alignment to improve azimuth alignment accuracy significantly. However, due to the existence of magnetic drifts in the fiber optic gyro, under the comprehensive influence of outside conditions, there will be residual drifts that cannot be averaged out along the body frame or the geographic frame, which will have a significant impact on azimuth alignment accuracy. An innovative and effective calibration compensation strategy is proposed by analyzing the generation mechanism of residual drifts and their influence on alignment accuracy, which can significantly improve azimuth alignment accuracy. With the aid of a high-precision total station, the experimental results of initial alignment in four directions show that the accuracy of azimuth alignment is improved from to by compensating residual drifts, which has significant theoretical significance and practical value in engineering applications for improving the overall performance of the INS.

Real-time Accelerometer-Based Event Detection Through KNN Classification Method

Real-time pattern and activity recognition techniques have experienced a recent surge in the use of advanced statistical techniques for analyzing data. More explicitly, Machine Learning classification methods have been used in a variety of applications and for different purposes, such as recognizing different types of events from accelerometer data (e.g. in smart watches, wearables, and vibration analysis). The objective of this work is to present a novel use of accelerometer-based pattern recognition techniques to detect the urban space infrastructure characteristics based on their effect on a vehicle’s body frame dynamics. For this study, we focus on detecting speed bumps, potholes and curves based on a real-time data streaming with the objective of rendering a street digitalization to automatically update an urban space Digital Twin. The present study has achieved real-time event detection for an urban trajectory with high accuracy which yields data that can be later fused with other sensors data. This approach is effectively contributing to the infrastructure layer of a multi-layered approach of digital modelling. Furthermore, the results contribute to expand the body of knowledge of real-time accelerometer event recognition techniques.

New Solution to Euler’s Equations for Asymmetric Bodies: Applications to Spacecraft Reorientation

This work derives the kinematic and dynamic solution to Euler’s equations of motion for an asymmetric rigid body subject to a torque aligned parallel or antiparallel to the instantaneous angular momentum vector. These are the first complete solutions to Euler’s equations for an asymmetric rigid body subject to nonaxial torques. The antiparallel solution is shown to be the optimal trajectory for spacecraft detumbling subject to a bound on the Euclidean norm of the applied torque. Comparisons to a numerically integrated optimal control law validate the solution for highly asymmetric spacecraft and long maneuver times. Combining the parallel and antiparallel torque solutions allows for the analytical expression of a rest-to-rest reorientation maneuver for any asymmetric spacecraft. This maneuver is completely parameterized by a single body frame angular momentum vector, and is thus termed a momentum-axis maneuver. Comprehensive trade studies indicate that the momentum-axis maneuver is superior in terms of maneuver time to time-optimal eigenaxis maneuvers for large-angle rotations, and generally within of numerically computed true optimum solutions. As these solutions are both analytic and computationally cheaper than either the eigenaxis or true optimum solutions, this approach could have widespread applications for spacecraft attitude control.

Square-Root Robocentric Visual-Inertial Odometry With Online Spatiotemporal Calibration

Robocentric visual-inertial odometry (R-VIO) in our recent work [1] models the probabilistic state estimation problem with respect to a moving local (body) frame, which is contrary to a fixed global (world) frame as in the world-centric formulation, thus avoiding the observability mismatch issue and achieving better estimation consistency. To further improve efficiency and robustness in order to be amenable for the resource-constrained applications, in this paper, we propose a novel information-based estimator, termed R-VIO2. In particular, the numerical stability and computational efficiency are significantly boosted by using i) the square-root expression and ii) incremental QR-based update combined with back substitution. Moreover, the spatial transformation and time offset between visual and inertial sensors are jointly calibrated online to robustify the estimator performance in the presence of unknown parameter errors. The proposed R-VIO2 has been extensively tested on public benchmark dataset as well as in a large-scale real-world experiment, and shown to achieve very competitive accuracy and superior time efficiency against the state-of-the-art visual-inertial navigation methods.

Validating the diagnostic performance of MUAC in screening moderate acute malnutrition and developing an optimal cut-off for under five children of different regions in Ethiopia

Valid and reliable anthropometric indicator is useful for early detection and treatment for under nutrition. Although, mid upper arm circumference (MUAC) is used for screening of children with moderate acute malnutrition in Ethiopia, its performance for the different ethnic groups has not been evaluated. To determine the diagnostic performance of MUAC for determination of moderate wasting among children of different ethnic background and develop optimal cut-off. A community based cross-sectional study was conducted among under five children of the three regions namely: Somalia, Amhara and Gambella Regions. The diagnostic performance of MUAC was validated using weight for height Z-score< -2 as a gold standard binary classifier. Test variable is mid upper arm circumference (MUAC< 12.5cm) and weight for height Z-Score (WHZ) is standard variable. ROC analysis performed based on the assumptions of MUAC value lower the cut-off point indicates the undernutrition. Area under the curve and validity measures (sensitivity and specificity) was generated as parameter estimated. The results were presented using tables and ROC curves. Except in the Gambella region, there was fair agreement between MUC<12.5cm and Weight for Height Z score<-2 in diagnosing wasting in Somali (Sensitivity = 29.3%, Kappa = 0.325, P<0.001) and in Gambella regions (Sensitivity = 16.7%, Kappa = 0.19, P<0.001). In Amhara region there was fair agreement between the two measures in diagnosing moderate acute malnutrition (MAM) (Sensitivity = 16%, Kappa = 0.216). For the Overall sample, the sensitivity of MUAC<12.5cm was 20.6% (Kappa = 0.245, P<0.001. Based on ROC analysis, the optimal cutoff value of MUAC for diagnosing moderate acute malnutrition for the two regions namely for Gambella and Amhara was 13.85cm with sensitivity of 0.99 and 1.00, respectively. However, for Somali Region the optimal cut was 13.75cm (Sensitivity = 0.98 cm and specificity = 0.71). Findings revealed that the inter reliability of measurement for MUAC< 12.5cm and WHZ<-2 for diagnosing MAM was low among different ethnic groups with the cut-off varying in each region. The existing cutoff point is less sensitive for diagnosis of MAM. As Ethiopia is home of diverse ethnic groups with different body frame and environmental conditions, the new cut off points developed for each region recommended to be used for screening moderate acute malnutrition to prevent relapse of MAM and reduce chronic malnutrition.

Factor Analysis of Genetic Parameters for Body Conformation Traits in Dual-Purpose Simmental Cattle.

Simple SummaryBody conformation traits are closely related to economically important characteristics and should be considered in cattle breeding programs. A variety of body conformation traits recorded by classifiers can complicate the analysis process. Factor analysis can reduce the number of variables by combining two or more variables into a single factor, which has biological significance. The results of this study could be used by breeders to define conformation indexes and implement genetic assessments for conformation traits in dual-purpose breeds.In this study, we estimated the genetic parameters for 6 composite traits and 27 body conformation traits of 1016 dual-purpose Simmental cattle reared in northwestern China from 2010 to 2019 using a linear animal mixed model. To integrate these traits, a variety of methods were used as follows: (1) genetic parameters estimates for composite and individual body conformation traits based on the pedigree relationship matrix (A) and combined genomic-pedigree relationship matrix (H); (2) factor analysis to explore the relationships among body conformation traits; and (3) genetic parameters of factor scores estimated using A and H, and the correlations of EBVs of the factor scores and EBVs of the composite traits. Heritability estimates of the composite traits using A and H were low to medium (0.07–0.47). The 24 common latent factors explained 96.13% of the total variance. Among factors with eigenvalues ≥ 1, F1 was mainly related to body frame, muscularity, and rump; F2 was related to feet and legs; F3, F4, F5, and F6 were related to teat placement, teat size, udder size, and udder conformation; and F7 was related to body frame. Single-trait analysis of factor scores yielded heritability estimates that were low to moderate (0.008–0.43 based on A and 0.04–0.43 based on H). Spearman and Pearson correlations, derived from the best linear unbiased prediction analysis of composite traits and factor scores, showed a similar pattern. Thus, incorporating factor analysis into the morphological evaluation to simplify the assessment of body conformation traits may improve the genetics of dual-purpose Simmental cattle.

Adoption of triply periodic minimal surface structure for effective metal hydride-based hydrogen storage

Metal hydrides (MHs) are highly effective for storing hydrogen because of their stability, relatively low temperature and pressure, and high volumetric hydrogen density. However, their gravimetric density is low because of the weights of the MHs, leading to a low potential for mobility applications unless the reactor also acts as a body frame, thereby compensating for the light weight. Triply periodic minimal surface (TPMS) structures show great potential as heat exchangers (HEs) with extended surface properties per volume and reinforced structures designed to bear mechanical loads. Therefore, these structures are considered promising for application as hydrogen carriers, especially in MH-based hydrogen storage. This study aims to develop MH-based hydrogen storage using a TPMS structure. Furthermore, a mathematical model was developed to analyze and improve its performance in terms of the hydrogen absorption and desorption rates. The analysis using the mathematical model was validated with existing experimental data. Different cooling conditions were compared with natural convection. Moreover, finite element analysis was applied to evaluate the capability of the current structure design in withstanding the working pressure and load. This study's important finding is that the propose structure is proven to have higher hydrogen storage performance, including density and hydrogen charging and discharging performances. In addition, it is also found that improving the cooling conditions could increase the absorption rate. Forced convection (with a heat-transfer coefficient of 500 W/m2·K) seems to be a preferable cooling solution that requires low energy consumption and provides sufficient cooling. By using this cooling condition with the proposed TPMS reactor design, 90% of hydrogen is absorbed within 2000 s. Natural cooling requires almost double that time. It was also found that a reactor with a TPMS structure with a 1 mm wall thickness design could withstand MH working pressure conditions and a compression load of 5000 N. Based on this finding, the TPMS-based structure can be considered as a promising novel way of storing hydrogen for mobility applications.

3D-Printed Satellite Brackets: Materials, Manufacturing and Applications

Brackets are the load-bearing components in a satellite. The current age of satellites comprises specific brackets that set out as a link between the bodies of the satellite, reflector parts, and feeder facilities mounted at its upper end. Brackets are used to carry loads of the satellite body frame, supporting elements, batteries, and electronic goods. The article explicates the various brackets used in satellites and aircrafts. The strength of the bracket is of utmost importance since it is an important load supporting member in several assemblies of aircraft and satellites. In addition to the mechanical strength, the weight of the bracket is a major concern as it adds to the total weight of the aircraft and satellite. Thus, weight savings of brackets can be of paramount importance and Additive Manufacturing (AM) is found as an overall solution to achieve the same. Hence, in addition to various brackets used in satellites, the article presents an exhaustive review of the processing of various advanced functional materials using various AM techniques to make high strength-to-weight ratio satellite brackets. The use of DFAM by various satellite manufacturers globally for optimizing the structure of the brackets resulting in a significant weight saving of the brackets is also presented in the article.

Development of an autonomous vision sensor-actuator-based circumferential seam path tracker welding machine/device for LPG cylinders

This paper presents an autonomous vision sensor-actuator-based circumferential seam path tracker welding machine/device for LPG (Liquefied Petroleum Gas) cylinders. The machine or device is designed to avoid various hazardous health issues that are found in the workers due to unfavorable working conditions during the welding process because of high temperature, dangerous fumes, and a large amount of luminous flux in the workstation. This machine involves a pneumatic holder to hold the cylindrical workpiece inside a metallic body frame. When the cylindrical workpiece rotates in a pneumatic holder, some amount of deflection arises due to the improper arrangement of fixtures and cylinders. It is not easy to overcome this deflection in fixtures, and due to this, the welding process is not done correctly. The undercut and overcut errors can also be found due to the improper shape of fixtures and cylinders. Therefore, the box setup is designed to cope with this problem, and the box contains an RGB (Red Green Blue) camera, LED (Light Emitting Diode), and an ultrasonic sensor. The box is installed in front of the welding torch to capture the image of the seam path of the workpiece. Firstly, the image is created with the help of a LED fitted inside the box. The LED creates the shadow of the joggle joint of the cylindrical workpiece. The camera captures that shadow. After capturing the image of shadow, the centroid of the seam path (represented by shadow) of the cylindrical workpiece is traced. It is sent to the Raspberry Pi microcontroller, and the data of the image is stored in the memory of the microcontroller for further processing. According to the position of the centroid coordinate, the microcontroller sends the control commands to the microstep driver of the stepper motor to follow this centroid coordinate. By this, the torch is controlled, and the welding process is done autonomously. The experimental setup is made, and the autonomous welding process is performed in many cylinders. Moreover, after performing autonomous welding process in the cylinder, the high-pressure bursting test (which is basically done by cylinder manufacturer industries) is performed to verify the effectiveness and efficiency of the welding joints. In the bursting test result, it is found that the cylinder is burst in a longitudinal direction, which verifies the effectiveness and efficiency of the obtained circumferential joggle joints

Morphometric traits and structural indices of indigenous cattle reared in Bench Sheko zone, southwestern Ethiopia

This study was carried out with the aim of applying morphometric traits and structural indices in assessing the type and function of indigenous cattle in the Gidi-Bench (GB) and Debub-Bench (DB) districts of the Bench-Sheko zone. The study included two hundred forty (240) households (120 from each district). About 660 matured cattle (60 male and 600 female) were selected for morphometric measurement, from which 14 structural indices were computed. For cattle linear body measurement, 15 characters were assessed, whereas 16 traits were considered for qualitative observation. The finding indicated that, except for tail length (TL), cattle in DB had higher (p < 0.05) values for Body Weight (BW), chest girth (CG), head length (HDL), height at wither (HW), Body length (BL), Horn length (HL), height at rump (HAR), height at rump (RL), RW (rump width), Neck Width (NW), Neck length (NL) Chest depth (CD), ear length (EL) and neck circumference (NC) than those of GB district. GB bulls had higher (p < 0.05) Body Index (BI), cephalic index (CI), and Balance (Ba) than DB districts. Conversely, the Height Index (HI), Rump Length Index (RLI), Body Index (BI), Body Weight Index (BWI), Body Ratio (BR), and Height Slope (HS) of DB bulls were higher (p < 0.05) than those of GB districts. The HI, RLI, BWI, Ba, and BR values were higher (p < 0.05) for cows of DB than those of GB districts. However, cows in GB had higher (p < 0.05) Length Index_1 (LI_1), CI, Pelvic Index (PI), Over increase Index (OVII), Length Index_1 (LI_2), and HS values compared to DB district. Therefore, morphometric features and body indices revealed that cattle reared in DB could be categorized as a small-sized and angular-shaped body frame with the ability to graze in rough terrain. In contrast, cattle in GB were categorized under small-sized animals whose morphology corresponds to dual-type, specifically bulls with the light draft.

Calibration of Radar RCS Measurement Errors by Observing the Luneburg Lens Onboard the LEO Satellite.

Accurate radar RCS measurements are critical to the feature recognition of spatial targets. A calibration method for radar RCS measurement errors is proposed for the first time in the context of special target tracking by observing the Luneburg Lens onboard the LEO satellite. The Luneburg Lens has favorable RCS scattering properties for the radar microwave. Thus, the laboratory RCS measurements of the Luneburg Lens, with some fixed incident frequency and with different incident orientations for the radar microwave, will be implemented in order to build a database. The incident orientation for the radar microwave in the satellite body frame will be calculated by taking advantage of the precise orbit parameters, with errors only at the magnitude of several centimeters and within the actual satellite attitude parameters. According to the incident orientation, the referenced RCS measurements can be effectively obtained by the bilinear interpolation in the database. The errors of actual RCS measurements can thus be calibrated by comparing the referenced and the actual RCS measurements. In the RCS measurement experiment, which lasts less than 400 s, the actual RCS measurement errors of the Luneburg Lens are nearly less than 0 dBsm, which indicates that the RCS measurement errors of the spatial targets can be effectively calculated by the proposed calibration method. After the elaborated calibration, the RCS measurements of the spatial targets can be accurately obtained by radar tracking.

Common Somali Indigenous Chicken Breeds, in Mogadishu, Somalia

The main aim of this report is to determine the phenotypic characteristics of Somali indigenous chickens. This research is the initial stage toward a future initiative to differentiate and improve Somali local chicken breeds. There are several indigenous and exotic chicken breeds in Somalia, as well as many other hybrids of chicken; however, this study focused on indigenous breeds that differ in body form, colors, comb type, and capacity to adapt to a given environment in Somalia. The five main indigenous chicken breeds in Somalia. The first indigenous chicken (IC) is Dooro Tiyeglow (Tiyeglow chicken), they have well adapted mostly to agro-pastoral communities’ regions like Bakool region and it has a remarkable beard feather, it also has a single upright comb broad. The second (IC), is Qoordiir (Naked Neck chicken), which is indigenous chicken mostly they have some tassel in the front part of its neck. The prominent plumage color is white and red stripes or red with white strips. Third (IC), is Dooro Jarray (Somali short chicken), this chicken is part of an eco-friendly chicken and is well-known for its small body size. And the common feature of this chicken is black shanks or gray-black shanks. Fourth (IC) is Dooro Buuftoy (Ovambo chickens), this chicken is considered to be smaller in size than exotic chickens, yet it comes in black and red colors. This has a strong personality and is very aggressive. The Fifth (IC) is Dooro Sawahili (Swahili chicken) this chicken is an exotic species that interbreed many local chickens, comes from many angles, has a huge body frame, and is good in egg production. The recommendation of this study is to undertake a government policy to encourage the conservation of Somalia's indigenous chicken breeds in order to prevent extinction and to make development and improvement of local chickens.

Electric Car Frame Body Design Fullset Dynamo Capacity 3.000 Watt With Solidworks Modeling 2020

The problem of safety and comfort of the means of transportation is closely related to the construction of the main frame of the vehicle. In this study, the frame body of an electric car with a capacity of 3.000 watts is the object of study, in order to determine the simulation of loading on the frame body of an electric car with a capacity of 3.000 watts. The research was conducted using an experimental method with the help of the Solidworks 2020 software. The data analyzed was data from the results of testing the design drawing of a 3.000-Watt electric car body frame designed with Solidworks Software and simulated loading of 50 N, 100 N and 150 N. The simulation results of Von mises stress loading of 50 N with a maximum value of 1,670 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly that is 1,009 x 10-2 N/m2 marked with color blue on the simulation graph. The simulation results of Von mises stress loading of 100 N with a maximum value of 3.43 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly, namely 4.57 x 10-2 N/m2 is marked in blue on the simulation graph. The simulation results of Von mises stress loading of 150 N with a maximum value of 5.018 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly, namely 2.150 x 10-2 N/m2 marked with color blue on the simulation graph.

메를로 퐁티의 현상학적 관점에서 무용의 철학적 의미

Objectives The purpose of this study is to philosophically explore the physicality of dance from the perspective of Merleau-Ponty phenomenology. Methods Analysis of Discourse in Qualitative Research Methods Results Merleau-Ponty can systematize phenomenological thinking about the body, that is, the body frame, in the sense of time and space, and it can be said that it provides an analysis frame. When interpreted in this context, dance is a body-based area, and it can be expected that it can be revealed as a performance embodied in various types through training or teaching in artistic and educational aspects. Conclusions Dance implies that it is an aesthetic medium that makes human life beautiful. Therefore, physicality can be assumed that everyday life is revealed as a body in time based on aesthetic sensitivity. Therefore, it mentions the need for a philosophical approach of researchers who can reflectively understand and perform the body's subjectivity revealed in dance.

Development of bus body technologies in terms of corrosion and durability

The object of this study is the technology of bus bodies and the formation of recommendations for design bodywork subject to the regulated durability of the body introduced into production. Advancing the technology of manufacturing bus bodies implies improving anti-corrosion protection, using new polymeric materials, and reducing the length of welds. The issue of corrosion resistance of bus bodies has been considered. It is established that the use of new polymeric materials will increase the corrosion resistance of bus bodies while existing technologies weakly protect against corrosion (resource up to 5 years). The peculiarity of this study is that the adhesion of new materials has been tested, with artificial aging, which confirms the durability of glued joints. According to the old technology, the body was exposed to anticorrosive treatment after welding the cladding with uncovered places left between the frame and body cladding, which provoked corrosion. The main idea is that in the new technology, the cladding is welded or glued after the body frame is fully coated with primer. New technologies and materials not used in the automotive industry have been proposed. Three variants of technologies were put into production. First: the welding of steel zinc sheets. In welding sites, the frame is covered with conductive primer. It was implemented for school buses (after 7 years, without damage). Second: gluing steel zinc sheets. It was implemented for city buses (after 6 years, without damage). Third: gluing sheets from composite materials not used in the automotive industry. The transition to new adhesive cladding technologies from composite corrosion-resistant materials instead of steel sheet, reduces by 2.5–3 times the length of welds (up to 20 years without damage). The studies have confirmed the strength of glued joints (cohesion rupture exceeds 95 %). The reliability of glued joints and high corrosion resistance of the body have been confirmed in the operation of buses. The scope of practical use of the results: bus-building plants. The reported results are suitable for production of all types while cataphoretic coatings are only for mass production

Concepts in Hip Implant Body Contouring: Patient Evaluation &amp; Implant Fabrication

Introduction: One of the most requested aesthetic procedures is body contouring using liposuction. Adjunctive procedures using fat grafting can provide enhancement in most body areas, commonly used in both gluteal and hip augmentation. Performing processing and enrichment to optimize fat transfer survival can avoid the use of body implants. When there is insufficient fat for the desired degree of augmentation, silastic implant placement is an alternative treatment. Much has been written in the medical cosmetic literature regarding gluteal and breast implants, but nothing in terms of hip silastic implants. Material and Methods: Hip implant patient selection, the body frame analysis, associated enhancing body contouring procedures, implant design and fabrication, and implant surgical placement are analyzed. In 3 different cosmetic surgery practices, methods of patient analysis and the process of creating a custom hip implant is presented. Techniques and protocols in the use of fat grafting in association with both gluteal and hip implants are elucidated. Results: The minimally manipulating fat maneuvers to increase fat survival are detailed. This paper defines the process of planning, designing, and fabricating a custom hip implant with significant patient input. By definition, patient-specific or custom implants can be any shape, size, and projection. The patient and surgeon provide the implant fabrication company a paper tracing of the surface area of the proposed implant along with the maximum projection. Engineering creates a 2-dimensional drawing using a computational software for intelligent system design or CAD. The implants are fabricated with input from the surgeon on silastic durometer, implant alterations to lower weight and enhance ease of folding for placement, and shape. Caveats and pitfalls in surgical planning, implant design, fabrication, and surgical placement are identified. Discussion: Body contouring using ultrasound liposuction may provide the desired aesthetic result. When augmentation is requested, fat transfer is the preferred initial procedure. If there is an insufficient volume of fat to augment both the buttocks and hip area, hip fat grafting is preferred to avoid a hip alloplastic implant. The reason for this treatment recommendation is to avoid the hip implant with a higher risk profile. Once the indication for the hip implant is confirmed, usually because of either inadequate presence of fat or a desired maximum hip projection that cannot be attained by fat grafting alone, the body shape analysis is finalized. Conclusion: Custom silastic hip implants are designed, fabricated, and surgically placed to provide the patient desired cosmetic hip augmentation.

해군 함정 탑재용 전자장비 랙의 수직 기둥 단면 형상 설계에 관한 연구

Elastic mounts are applied to electronic equipment racks (EERs) mounted on naval vessels to reduce forces transmitted from external impacts or vibration. EERs should be designed to have sufficient structural capability to address the exposed forces during its service life-cycle, and the main focus should be on the body frame because most of the stiffness of the EER is supported by the responsible body frame. An EER’s body frame can be divided into two parts, a horizontal rack and a vertical column, and the structural rigidity from the vertical columns plays an essential role in supporting the overall stiffness of the EER. This study aims to find the acceptable minimum second moment of inertia of the cross-section at a vertical column among four candidates to satisfy the required structural stiffness of the EER. The maximum stress of each cross-sectional frame structure is calculated by the transient response analysis of the body frame under the impact force according to the BV-043 specification. The feasibility of the structural stiffness is initially evaluated by the modal analysis of the finite-element model of the body frame of the EER, and it is verified by performing an experimental modal test of a prototype of the responsible body frame. The test results revealed that the designed cross-section of the vertical column is capable of supporting the EER system over the require vibration test, MIL-167-1A, because all resonance frequencies were marginally higher than the service frequency, which ranged from 4 Hz to 33 Hz.

Electric Car Frame Body Design Fullset Dynamo Capacity 3.000 Watt With Solidworks Modeling 2020

The problem of safety and comfort of the means of transportation is closely related to the construction of the main frame of the vehicle. In this study, the frame body of an electric car with a capacity of 3.000 watts is the object of study, in order to determine the simulation of loading on the frame body of an electric car with a capacity of 3.000 watts. The research was conducted using an experimental method with the help of the Solidworks 2020 software. The data analyzed was data from the results of testing the design drawing of a 3.000-Watt electric car body frame designed with Solidworks Software and simulated loading of 50 N, 100 N and 150 N. The simulation results of Von mises stress loading of 50 N with a maximum value of 1,670 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly that is 1,009 x 10-2 N/m2 marked with color blue on the simulation graph. The simulation results of Von mises stress loading of 100 N with a maximum value of 3.43 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly, namely 4.57 x 10-2 N/m2 is marked in blue on the simulation graph. The simulation results of Von mises stress loading of 150 N with a maximum value of 5.018 x 106 N/m2 are marked in red on the simulation graph, while the minimum value from the simulation results can be concluded directly, namely 2.150 x 10-2 N/m2 marked with color blue on the simulation graph.

A Low-Cost Attitude Determination System using Multiple Sensors for High-Altitude Balloon Flights

This paper discusses the calibration and implementation of a low-cost attitude determi- nation system for high-altitude balloon flights using multiple sensors. The attitude determination system is comprised of a 3-axis accelerometer and a sun sensor. The accelerometer is utilized to measure the gravitational acceleration vector of the payload in the payload's body frame. The measured acceleration vector is based upon the accelerometer's bias and sensitivity which can be found through calibration under zero motion conditions. The sun sensor is comprised of many solar cells at various angles. These are utilized to obtain an accurate sunlight directional vector of the payload in the payload's body frame from an over-determined system of measurement equations. The development of these equations is discussed. Both the gravitational acceleration vector and the sunlight directional vector can also be measured in an inertial frame. It is assumed that these measurements are known a-priori. This provides enough information to solve for an attitude at each sample instance, utilizing two independent vector measurements (i.e., the sunlight and acceleration vectors). The attitude determination system utilizes Markley's solution to Wahba's problem. A 3-axis rate gyroscope is also utilized to gather angular velocity information of the payload in the payload's body frame and was used to compare against angular velocity derived from the estimated attitude to validate the accuracy of the attitude determination system. The measured angular velocity vector is based upon the rate gyroscope's bias and sensitivity which can be found through calibration under zero motion conditions.