Stewart Platform Research Articles

FOUR-BAR MECHANISM FOR A PORTAL CRANE: A BRIEF OVERVIEW

The present article aims to increase knowledge of a four-bar mechanism. A four-bar system is a planar mechanism. There are many types of simple mechanisms, such as: Chebyshev, Chebyshev lamda, Hoecken, Roberts, Watt’s, Grasshopper, horse-head, pantograph and Peaucelier. More complex mechanisms are: Stewart platform or Jansen’s linkage. The determination of the degrees of freedom (DOF) for a system is done using the Chebychev-Gruebler-Kutzbach relationship. Due to this fact, the DOF for the four-bar system has the value one. Moreover, we analyze the following angles: θ, α, β and φ3in the mechanism. Finally, using Matlab software the drawing and the dynamic simulation of a four-bar mechanism is carried out. Besides, the dynamic simulation is represented after 3s, 6s and 12s.

Novel model predictive control-based motion cueing algorithm for compensating centrifugal acceleration in KUKA robocoaster-based driving simulators.

The washout motion cueing algorithm (MCA) is a critical element in driving simulators, designed to faithfully reproduce precise motion cues while minimizing false cues during simulation processes, particularly deceptive translational and rotational cues. To enhance motion sensation accuracy and optimize the use of available workspace, model predictive control (MPC) has been employed to develop innovative motion cueing algorithms. While most MCAs have been tailored for the Steward motion platform, there has been a recent adoption of the motion platform based on KUKA Robocoaster as an economical option for driving simulators. However, leveraging the full potential of the KUKA Robocoaster requires trajectory conversion of the motion base. Thus, this research proposes a novel MCA specifically designed for the KUKA Robocoaster-based motion platform, utilizing large planar circular motion to simulate lateral movement for drivers. Nonetheless, circular motion introduces disruptive centrifugal forces, which can be mitigated through proper pitch-tilted angles. The novel MPC generates simulated motion that accurately follows the lateral specific force target and effectively maintains the roll angular velocity below its threshold value. Additionally, it compensates for disturbing centrifugal acceleration by implementing pitch rotational motion, ensuring the pitch angular velocity remains below its threshold. Simulation tasks conducted on the motion platform, focusing solely on lateral acceleration, demonstrate the successful elimination of false motion cues in both the roll/sway and pitch/surge channels. The proposed innovative MPC solution offers an original approach to motion cueing algorithms in KUKA Robocoaster-based driving simulators. It enables the exploitation of the KUKA Robocoaster platform's capabilities while delivering accurate and immersive motion cues to drivers during simulation experiences.

Model of Basic Locomotor Movement with Balance for 1st Grade Elementary School Children

The purpose of this study was to obtain information in the process of implementing basic locomotor movement learning with balance, creating and transmitting the learning process with basic locomotor movement models with balance for elementary school children in grade I to obtain empirical data about the effectiveness and efficiency and interest of children from the motion learning process. basic locomotor with balance for elementary school children in class I and created a learning model book for teachers as a guide for teaching basic locomotor movements with balance for elementary school children. This will increase effectiveness and efficiency as well as increase children's motivation to learn basic locomotor movements with balance. This research was conducted at SDN Semanan 14 Petang, West Jakarta, with 32 children as research objects. This study uses the ADDIE learning development model, which in this model starts at the stages of Analysis, Design, Development, Implementation, and Evaluation. From the results obtained, the basic locomotor motion learning model with this balance turned out to be very effective to be applied in learning. From the results obtained, the basic locomotor motion learning model with this balance turned out to be very effective when applied in learning. This can be seen from the increase in pre-test and post-test by using the paired sample test on the SPSS 25.0 T-Test. The difference in significance on T-count is shown as -98.097 df = 31, p-value = 0.001 <0.05 ; With this, there appears to be a significant increase in the results of the assessment of children's skills at SDN Semanan 14 Petang Class I.

A Colorful Question Game to Improve Children Motor Skills in 4th Class Elementary School

This research aims to develop a basic motor skills learning model through game activities tailored to the developmental stages of students' ages. The game model used in this research is called "Colorful Question." This game is designed to enhance locomotor skills, particularly the basic movements of jumping and hopping, which are highly beneficial for training leg muscle strength, coordination, attention focus, and cognitive abilities of students. The research follows the ADDIE model (Analysis, Design, Development, Implementation, and Evaluation). The subjects of this study are fourth-grade students in both boys' and girls' elementary schools, consisting of 27 participants in a small-scale pilot test and 65 participants in a large-scale pilot test. Validation results from experts show a CVI (Content Validation Index) value of 3.57 and a CVR (Content Validity Ratio) of 0.01, indicating that the developed "Colorful Question" game has high validity and is suitable for fourth-grade elementary school students, making it suitable for field testing (empirical validation).

A Conceptual Model for the Flutter Mechanism in Interlocked Turbine Blades

Abstract Many turbine rotor blades adopt the interlock configuration; among its advantages, there is a large increase in the natural frequencies with respect to the simpler cantilever configuration. Most widespread assessment methods estimate that this frequency increase should lead to a large improvement to the flutter stability of the interlocked rotor rows; some well-known approaches, such as the Panovsky–Kielb stability maps, suggest that flutter should be very unlikely for interlock configurations. Nevertheless, both the experience and detailed simulations indicate that it is possible to find flutter in interlocked blades, even with moderate aspect ratio. In this paper, the authors study the underlying physics behind flutter for interlocked blades, and present a very simplified model that is able to reproduce the main modal characteristics of interlocked blades, including the frequency increase and change in mode-shape as a function of the nodal diameter. This model also identifies a flutter mechanism, which is dependent on the aerodynamic interaction between the bending and torsion motion of the blade; even if both basic motions are individually stable, their interaction may lead to a coupled aeroelastic instability. The results from this simplified model are fully consistent with detailed three-dimensional linearized unsteady computational fluid dynamics simulations of representative turbine rotor blades, and should be of application in many realistic cases of interlock flutter. Finally, the authors present a study on the influence of the main parameters of the simplified model on the flutter stability, and derive some conclusions about the implications on flutter-free interlock design.

Dynamic analysis of the joint movement of the hoisting and slewing mechanisms of a boom crane

To increase the productivity of boom cranes, the operation of individual mechanisms is combined. At the same time, dynamic loads on structural elements, drive mechanisms and loads on a flexible suspension increase, which reduces the reliability of crane operation and increases energy losses. Therefore, the research aims to consider the problem of the dynamics of the joint movement of the mechanisms for load slewing and hoisting of a boom crane. To study the dynamics of the joint movement of the mechanisms, the boom system was represented by a mechanical system with 6DOF, where the basic movement of the mechanisms and the oscillatory movement of the structural links with elastic and dissipative properties, as well as the load on a flexible suspension in the plane of crane slewing and hoisting were considered. For such a mechanical system of a crane, the differential equations of the joint motion of the crane slewing and hoisting mechanisms were developed. The obtained equations are a system of the second order nonlinear differential equations, for solving which a numerical method in the form of a computer program was used. Using the developed program, the dynamics of the joint movement of the mechanisms of a jib crane with specific numerical parameters were calculated. Based on the calculations, a dynamic analysis of the joint movement of the mechanisms for slewing and hoisting the load of a jib crane with a hoisting boom was carried out, which revealed high-frequency vibrations of links with elastic and dissipative properties, as well as low-frequency oscillations of the load on a flexible suspension. The greatest impact of oscillations is observed during the start-up of mechanisms, where high-frequency oscillations dampen during the transient process, and low-frequency oscillations dampen over a fairly significant period. To improve the dynamic properties of the mechanisms for turning and hoisting a load during their joint movement, it is proposed to optimise the mode of movement in the areas of transient processes (start-up, braking). The research results can be used in the development and operation of cranes in mechanical engineering, construction, and other industries

Enhanced variants of crow search algorithm boosted with cooperative based island model for global optimization

The Crow Search Algorithm (CSA) is a swarm-based metaheuristic algorithm that simulates the intelligent foraging behaviors of crows. While CSA effectively handles global optimization problems, it suffers from certain limitations, such as low search accuracy and a tendency to converge to local optima. To address these shortcomings, researchers have proposed modifications and enhancements to CSA’s search mechanism. One widely explored approach is the structured population mechanism, which maintains diversity during the search process to mitigate premature convergence. The island model, a common structured population method, divides the population into smaller independent sub-populations called islands, each running in parallel. Migration, the primary technique for promoting population diversity, facilitates the exchange of relevant and useful information between islands during iterations. This paper introduces an enhanced variant of CSA, called Enhanced CSA (ECSA), which incorporates the cooperative island model (iECSA) to improve its search capabilities and avoid premature convergence. The proposed iECSA incorporates two enhancements to CSA. Firstly, an adaptive tournament-based selection mechanism is employed to choose the guided solution. Secondly, the basic random movement in CSA is replaced with a modified operator to enhance exploration. The performance of iECSA is evaluated on 53 real-valued mathematical problems, including 23 classical benchmark functions and 30 IEEE-CEC2014 benchmark functions. A sensitivity analysis of key iECSA parameters is conducted to understand their impact on convergence and diversity. The efficacy of iECSA is validated by conducting an extensive evaluation against a comprehensive set of well-established and recently introduced meta-heuristic algorithms, encompassing a total of seventeen different algorithms. Significant differences among these comparative algorithms are established utilizing statistical tests like Wilcoxon’s rank-sum and Friedman’s tests. Experimental results demonstrate that iECSA outperforms the fundamental ECSA algorithm on 82.6% of standard test functions, providing more accurate and reliable outcomes compared to other CSA variants. Furthermore, Extensive experimentation consistently showcases that the iECSA outperforms its comparable algorithms across a diverse set of benchmark functions.

Design and Experiment of a Multi-DOF Shaker Based on Rotationally Symmetric Stewart Platforms with an Insensitive Condition Number

This study proposes a method for designing a class of rotationally symmetric Stewart platforms (RSSPs) with an insensitive condition number (ICN), which is used to minimize the condition number to achieve a high accuracy for a multi-degree-of-freedom (multi-DOF) shaker. Considering the rotational symmetry of RSSPs, an analytical relationship between the architecture parameters and transfer coefficients is first established. Then, the decoupling conditions of the RSSPs are derived, and the transfer coefficient formulas are simplified by the given decoupling conditions and iso-length assumption. Following further analyses and discussions, the ICN condition and analytical form of the condition number are provided. The area of the ICN (AICN) is, subsequently, derived to evaluate the insensitivity of the condition number. To validate the effectiveness of the method, a design example (ICN-RSSP), along with a numerical analysis, is implemented, and, finally, a multi-DOF shaker is developed. The results of the numerical analysis show a smaller condition number and a larger AICN than those of the RSSP, for comparison. And the experiment results of the multi-DOF shaker show a high accuracy of vibration waveform reproduction. The method can reduce the condition number of RSSPs, improve the insensitivity, and further improve the accuracy of the multi-DOF shaker.

HUBUNGAN PIJAT BAYI DENGAN PERKEMBANGAN MOTORIK KASAR PADA BAYI USIA 3-6 BULAN DI NARESWARA MOM AND BABY CARE KUDUS 2022

Baby massage can stimulate the development of baby's gross motor skills, which is part of motor activity that involves large or gross muscle skills. The ability to use large muscles for babies is a basic movement ability. The purpose of this study is to analyze the relationship between infant massage and gross motor development in infants aged 3-6 months at Nareswara Mom and Baby Care Kudus. This study uses a quantitative method with a cross-sectional approach. The research sample consisted of 50 infants aged 3-6 months at Nareswara Mom and Baby Care, Kudus, with the sampling technique using total sampling. Analysis of research data using univariate and bivariate analysis using chi square. The results of the univariate analysis showed that there were 33 babies (66%) aged 3-6 months who were in the routine category, while there were 17 babies (34%) who were in the non-routine category. Furthermore, gross motor development was normal in 24 infants (48%), gross motor development in question was in 17 infants (34%), and gross motor development was deviant in 9 infants (18%). The results of the bivariate analysis showed that 22 respondents (44%) had normal gross motor development for infants aged 3-6 months who had regular massages, 9 respondents had doubts (18%), and 2 respondents had deviations (4%). Furthermore, infants aged 3-6 months in the non-routine category with normal gross motor development were 2 respondents (4%), doubtful 8 respondents (16%), and deviant 7 respondents (14%). Then the results of the chi square test show the sig. Asyim (P-Value) of 0.000 is less than 0.05 (0.000 <0.05). Statistically, there is a relationship between infant massage and gross motor development for infants aged 3-6 months at Nareswara Mom and Baby Care, Kudus. Thus it is hoped that mothers who have babies routinely provide baby massage stimulation in order to improve the baby's gross motor development.

Pengaruh Permainan Tradisional Egrang Batok Kelapa Dengan Kemampuan Gerak Dasar Lokomotor Anak Kelompok B

The study's objective is to improve the locomotor basic movement skill of Group B children by utilizing the traditional game Egrang Batok Kelapa as a media tool at TK State Bersehati Binjeita Kindergarten in Bolangitang Timur District, North Bolaang Mongondow Regency. The locomotor skills include walking, running, and jumping. This quantitative research used an experimental method with a pre-test and post-test research design. The subjects were tested before and after the treatment was given.

Development of Authentic Assessment Instruments of Football Passing, Dribbling, and Shooting Skills in Physical Education, Sports and Health Learning in Senior High School

This study aims at developing an instrument for authentic assessment of physical education, sports, and health learning outcomes on the basic movement skills of football games for senior high school students because the assessment of learning outcomes is very important in learning activities. The research method uses Research and Development (R&D) using a 4- D research model consisting of four steps, namely: (1) Define, defining by conducting a preliminary study of product needs, (2) Design, designing by compiling assessment rubrics adjusted to the curriculum, KI (core competencies) / KD (basic competencies), and materials, (3) Development, developing by validating with CVR (Content Validity Ratio) and reliability using Alpha Cronbach and ICC (Intraclass Correlation Coefficients), (4) Dissemination, product distribution for practitioner use. The subjects in this study were students of class XI of SMA Muhammadiyah Ponjong and SMAN 1 Depok, Special Region of Yogyakarta. The result of this study is the development of an authentic assessment instrument product of the basic motion of the football game. The results of the proof of validity using CVR (Content Validity Ratio) showed the results of 1, and the proof of reliability using Alpha Cronbach and ICC (Intraclass Correlation Coefficients) obtained the results of product trials at SMA Muhammadiyah Ponjong of r alpha cronbach = 0.770 and r ICC = 0.751. The large-scale test of the product was carried out at SMAN 1 Depok with the result of r alpha cronbach = 0.914. Therefore, the results of the proof of validity and reliability show that the product development of authentic assessment instruments for Physical Education, Sports and Health learning outcomes in basic football movement skills has a high level of reliability so that it can be used as an authentic assessment instrument.

State-input affine approximate modeling based on a differential neural network identifier

This work presents the development of a state-input affine differential neural network that approximates a class of nonlinear systems with uncertain dynamics and perturbations. The feasibility of using differential neural networks is based on the approximation capabilities of artificial neural networks, assuring that the approximation error of the right-hand side of the system with uncertain dynamics is bounded. The dynamics of the free parameters of the differential neural network is obtained using the Lyapunov's second stability method, which provides the convergence of the identification error to an invariant set around the origin. The approximation capabilities of the proposed identifier are compared with a classical differential neural network, aiming to identify the dynamics of a Stewart platform, which is used as testing example. The results show that the cumulative norm of identification's error is smaller using the state-input affine differential neural network, which demonstrates better identification outcomes with the proposed modified identifier. An additional advantage of the state-input affine differential neural network is that it has a quasi-linear structure that could help formulate a controller for several systems, which is a further research interest.

Kinematics and Statics of the Gough-Stewart Platform

This paper presents an algorithm for the kinematics and statics analysis of a Gough–Stewart platform. Through defining the velocity screw, the relative angular and linear velocities of a single rigid body can be expressed as a single vector. The velocity screw equations of various mechanisms are deduced in detail, the forward and inverse kinematics of a parallel mechanism can be solved through the velocity screw equation. Similarly, the definition of the force screw allows all constraint forces and torques of a single rigid body to be expressed using a single vector, and the static screw equation can be used to solve the forward and inverse statics of a parallel mechanism in one coordinate system. The advantage of this approach is that kinematics and statics modeling are unified in screw coordinates because the kinematic parameters in screw form can be directly employed in statics modeling. The results of the kinematics and statics analysis of the Gough-Stewart platform validate this method. This algorithm is easy to compute and program with high efficiency, and it can also be applied to any other spatial, complex multi-rigid-body systems.

Evaluation of forces in a racing simulator based on a Stewart platform

Evaluation of forces in a racing simulator based on a Stewart platform

Improving Fundamental Movement Skills in Early Childhood through Outdoor Play Based on Gender

Basic movement skill (FMS) is an important factor that can influence physical activities. Playing outside can support a child overall health, learning process, and basic motor skill development. The purpose of this study was to determine early childhood motor development through outdoor play based on gender differences. This study used an experimental method with a one-group pretest-posttest design. The study population consisted of preschool children aged 5–6 years. The sample included 30 preschool children selected using purposive sampling, consisting of 12 boys and 18 girls. TGMD-2 test instrument was used to measure FMS. The results showed that there was no difference of the effect of the outdoor play program on the basic motor skills (FMS) of boys and girls. Locomotor skills and control objects indicates that there was a significant effect of the program intervention. It concludes that early motor skills of boys and girls were improved after participating in an outdoor play program. According to the result of this study, it is necessary to conduct a more detailed approach on gender differences, especially on their basic motor needs and participations in programmed outdoor activities to encourage the development of basic motor skills (FMS).

Pelatiahan Gerak Dasar Bola Voli Di SMP PGRI 06 Gandrungmangu Desa Karanggintung Tahun 2023

Training on basic volleyball movements was held with the hope of increasing students' awareness of the importance of basic movements in the game of volleyball. Apart from that, basic volleyball movements are a series of movements used by volleyball players to control and manipulate the ball. These basic movements include receiving and attacking movements. By mastering the basic movements of volleyball, students can develop skills and abilities in playing volleyball. The basic movements of volleyball will go through several stages to get to the final stage, namely (1) providing material starting from the meaning, history of volleyball and when volleyball came to Indonesia. (2) practice basic volleyball movements (top serve, bottom serve, top pass and bottom pass). (3) there are volleyball games in general where children will play volleyball and in the game there are basic volleyball movements (bottom serve, top serve, bottom pass and top pass). (4) giving rewards. (5) students can perform basic movements well and correctly

The effect of a 12-week 'Brain Jogging' learning model on gross motor: locomotor skills

Study Purpose. The primary objective of this study was to test the effects of the 'brain jogging' learning model on basic locomotor movement abilities among elementary school students. Methods. This research is a quasi-experimental study, employing a two-group pretest-posttest design. The 'brain jogging' based learning model was compared to traditional learning models, specifically direct instruction. The sample consisted of 30 fourth-grade students, divided into two parallel grades, A and B, both possessing similar characteristics in terms of age, average height/weight, sports learning material, duration, and timing of sports learning sessions. Students receiving the 'brain jogging' based learning model treatment attended twice a week and maintained a 90% attendance rate. Each game or activity is aligned with a specific goal related to a 'brain jogging' sub-training item. Data were analyzed using SPSS IBM 26. Initial steps included comparing descriptive data to the entire population size, and establishing the distribution of variables, the mean, and the standard deviation (SD). Subsequently, an independent sample t-test was utilized to ascertain the effect of 12 weeks of the 'brain jogging' based learning model on the experimental group. Results. The mean difference in post-test scores between control and experimental groups was determined based on the significance level from the SPSS IBM 26 output (p < 0.05). The independent sample t-test revealed significant results in various categories: run (p = 0.000), gallop (p = 0.000), hop (p = 0.000), leap (p = 0.000), horizontal jump (p = 0.000), and slide (p = 0.009). Conclusions. Based on the independent sample t-test results, the hypothesis is accepted. This indicates significant differences between the control and experimental groups. Statistically significant improvements were observed in run, gallop, hop, leap, horizontal jump, and slide abilities among elementary school students. The 'brain jogging' based learning model presents a promising approach to enhancing locomotor skills.

Improving Fundamental Locomotor Skills of Elementary School Students in Padang City Through the Kids Athletics Model

The problem in this study is the low level of basic movement of students, especially in basic locomotor movements. The purpose of this research is to improve the basic movement of elementary school students through the kid’s athletics model. This research is development research with a model design adapted to the ADDIE development model. The steps taken are analysis, design, development, implementation and evaluation. Elementary school students in the city of Padang who are 9-10 years old, as well as the validators are four experts, namely two experts on evaluation and sports measurement tests, two experts on curriculum and materials. The results of the development of this kid’s athletics model, obtained a validation value according to experts an average of 95.9% so that the learning model can be said to be feasible. Then the reliability level was up to 0.989 in the small group trial and 0.996 in the large group trial, so that the learning model was said to be reliable for improving the basic movements of the kid’s athletics model. From the results of validation by experts, the practicality value obtained was a percentage of 96.7%. Then the value of its effectiveness, then obtained a percentage of 92.9%. Thus, it can be concluded that the kids’ athletics learning model is well used as a learning model to improve basic movements, especially basic locomotor movements for elementary school students. Keywords: Fundamental locomotor skills, athletics model, elementary school

Effectiveness of Nutrition and Play Activities in Enhancing Basic Motor Skills of Urban Children Over a 16-Week Period

This research was carried out on the basis of the low basic motor competence of urban children. It is estimated that there are many influencing factors including play activity methods and nutritional status. This study aims to determine the effect of play activity methods on nutritional status in urban children. This type of research is a quasi-experimental with a total sample of 40 people based on certain considerations. Basic movement skills are obtained by the TGMD-2 test which consists of object control and locomotor, then nutritional status data is obtained by measuring body mass index. Data were analyzed using a quantitative t test technique that describes comparative data. The results of the research and data analysis show that: 1) There are differences in the basic movement skills of students who have high and low nutritional status 2) There is an interaction between learning approaches and nutritional status. 3) There are differences in the basic movement skills of students who are given a playing approach that has a high nutritional status. 4) There are differences in the basic movement skills of students who are given a playing approach that has low nutritional status. The findings in this study show that children who have high nutrition enjoy playing activities more and are more physically active compared to children who have low nutrition in play activities. and play activity is an intermediary to see the movement skills of children Keywords: approach to play, nutritional status, basic movements of children, TGMD-2.

EOG acquisition system based on ATmega AVR microcontroller

This paper presents a hardware and software of an electrooculogram (EOG) acquisition system based on ATmega AVR microcontroller for the acquisition of vertical and horizontal eye movements. The presented system is used to acquire a dataset of eye movements for volunteers. This system gives two channels representing vertical and horizontal EOG signals. The frequency range of the EOG signal is known to be 0.1 to 10 Hz, and hence this frequency range is isolated with a High-Pass Filter (HPF) with a cutoff frequency of 0.1 Hz followed by a Low-Pass Filter (LPF) with a cutoff frequency of 10 Hz. The EOG acquisition system is interfaced with an ATmega AVR microcontroller to acquire a dataset that can be used for controlling hardware such as Light Emitting Diodes (LEDs), wheelchair, and robot arm. The presented system is composed of EOG signal acquisition, Ag/AgCl electrodes, analog-to-digital converter through Arduino Mega 2560 board microcontroller unit, trainer board, laptop, keypad, and Liquid Crystal Display (LCD). The eye movement is detected by measuring the potential difference between cornea and retina using five Ag–Agcl disposable electrodes. Different volunteers of different ages at different times have been treated with the presented system to obtain data. Classified vertical and horizontal EOG signals and the basic eye movements e.g., open eye, left, right, up, and down can be used to control robots and wheelchairs for rehabilitation purposes.