scholarly journals Topological Design Methods for Mecanum Wheel Configurations of an Omnidirectional Mobile Robot

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1268 ◽  
Author(s):  
Yunwang Li ◽  
Sumei Dai ◽  
Lala Zhao ◽  
Xucong Yan ◽  
Yong Shi
Keyword(s):  
Mobile Robot ◽  
Design Methods ◽  
Combination Method ◽  
Practical Applications ◽  
Replacement Method ◽  
Topological Design ◽  
Combination Methods ◽  
Mecanum Wheel ◽  
Bottom Roller ◽  
Basic Configuration

A simple and efficient bottom-roller axle intersections approach for judging the omnidirectional mobility of the Mecanum wheel configuration is proposed and proved theoretically. Based on this approach, a sub-configuration judgment method is derived. Using these methods, on the basis of analyzing the possible configurations of three and four Mecanum wheels and existing Mecanum wheel configurations of robots in practical applications, the law determining wheel configuration is elucidated. Then, the topological design methods of the Mecanum wheel configurations are summarized and refined, including the basic configuration array method, multiple wheels replacement method, and combination method. The first two methods can be used to create suitable multiple-Mecanum-wheel configurations for a single mobile robot based on the basic Mecanum wheel configuration. Multiple single robots can be arranged by combination methods including end-to-end connection, side-by-side connection, symmetrical rectangular connection, and distributed combination, and then, the abundant combination configurations of robots can be obtained. Examples of Mecanum wheel configurations design based on a symmetrical four-Mecanum-wheel configuration and three centripetal configurations using these topological design methods are presented. This work can provide methods and a reference for Mecanum wheel configurations design.

scholarly journals An improved conflicting-evidence combination method based on the redistribution of the basic probability assignment

2021 ◽  
Author(s):  
Zezheng Yan ◽  
Hanping Zhao ◽  
Xiaowen Mei
Keyword(s):  
Evidence Theory ◽  
Combination Method ◽  
Probability Assignment ◽  
Basic Probability Assignment ◽  
Combination Methods ◽  
Conflicting Evidence ◽  
Basic Probability ◽  
The Right ◽  
Conflict Intensity ◽  
Dempster’S Rule Of Combination

AbstractDempster–Shafer evidence theory is widely applied in various fields related to information fusion. However, the results are counterintuitive when highly conflicting evidence is fused with Dempster’s rule of combination. Many improved combination methods have been developed to address conflicting evidence. Nevertheless, all of these approaches have inherent flaws. To solve the existing counterintuitive problem more effectively and less conservatively, an improved combination method for conflicting evidence based on the redistribution of the basic probability assignment is proposed. First, the conflict intensity and the unreliability of the evidence are calculated based on the consistency degree, conflict degree and similarity coefficient among the evidence. Second, the redistribution equation of the basic probability assignment is constructed based on the unreliability and conflict intensity, which realizes the redistribution of the basic probability assignment. Third, to avoid excessive redistribution of the basic probability assignment, the precision degree of the evidence obtained by information entropy is used as the correction factor to modify the basic probability assignment for the second time. Finally, Dempster’s rule of combination is used to fuse the modified basic probability assignment. Several different types of examples and actual data sets are given to illustrate the effectiveness and potential of the proposed method. Furthermore, the comparative analysis reveals the proposed method to be better at obtaining the right results than other related methods.

scholarly journals Practical Model for Energy Consumption Analysis of Omnidirectional Mobile Robot

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1800
Author(s):  
Linfei Hou ◽  
Fengyu Zhou ◽  
Kiwan Kim ◽  
Liang Zhang
Keyword(s):  
Energy Consumption ◽  
Power Consumption ◽  
Mobile Robot ◽  
Load Capacity ◽  
Working Environment ◽  
Energy Consumption Analysis ◽  
Mecanum Wheel ◽  
Save Energy ◽  
Energy Consumption Modeling ◽  
Robot Platform

The four-wheeled Mecanum robot is widely used in various industries due to its maneuverability and strong load capacity, which is suitable for performing precise transportation tasks in a narrow environment. While the Mecanum wheel robot has mobility, it also consumes more energy than ordinary robots. The power consumed by the Mecanum wheel mobile robot varies enormously depending on their operating regimes and environments. Therefore, only knowing the working environment of the robot and the accurate power consumption model can we accurately predict the power consumption of the robot. In order to increase the applicable scenarios of energy consumption modeling for Mecanum wheel robots and improve the accuracy of energy consumption modeling, this paper focuses on various factors that affect the energy consumption of the Mecanum wheel robot, such as motor temperature, terrain, the center of gravity position, etc. The model is derived from the kinematic and kinetic model combined with electrical engineering and energy flow principles. The model has been simulated in MATLAB and experimentally validated with the four-wheeled Mecanum robot platform in our lab. Experimental results show that the accuracy of the model reached 95%. The results of energy consumption modeling can help robots save energy by helping them to perform rational path planning and task planning.

scholarly journals Research on Improvement of the Combination Method for Conflicting Evidence Based on Historical Data

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 762
Author(s):  
Shuai Yuan ◽  
Honglei Wang
Keyword(s):  
Decision Rule ◽  
Historical Data ◽  
Evidence Theory ◽  
Weighted Average ◽  
Combination Method ◽  
Final Decision ◽  
Evidence Based ◽  
Combination Methods ◽  
Conflicting Evidence ◽  
The Difference

In a multi-sensor system, due to the difference of performance of sensors and the environment in which the sensor collects evidence, evidence collected will be highly conflicting, which leads to the failure of D-S evidence theory. The current research on combination methods of conflicting evidence focuses on eliminating the problem of "Zadeh paradox" brought by conflicting evidence, but do not distinguish the evidence from different sources effectively. In this paper, the credibility of each piece of evidence to be combined is weighted based on historical data, and the modified evidence is obtained by weighted average. Then the final result is obtained by combining the modified evidence using D-S evidence theory, and the improved decision rule is used for the final decision. After the decision, the system updates and stores the historical data based on actual results. The improved decision rule can solve the problem that the system cannot make a decision when there are two or more propositions corresponding to the maximum support in the final combination result. This method satisfies commutative law and associative law, so it has the symmetry that can meet the needs of the combination of time-domain evidence. Numerical examples show that the combination method of conflict evidence based on historical data can not only solve the problem of “Zadeh paradox”, but also obtain more reasonable results.

Theoretical Considerations on the Health Checkup Accuracy of Combination Testing

2002 ◽  
Vol 41 (03) ◽  
pp. 216-219
Author(s):  
S. Shibata
Keyword(s):  
Odds Ratio ◽  
Optimum Combination ◽  
Combination Method ◽  
Health Checkup ◽  
Combination Methods ◽  
Sequential Tests ◽  
Theoretical Evidence ◽  
Sensitivity Specificity ◽  
Theoretical Considerations ◽  
Negative Rule

Summary Objectives: To find basic theoretical evidence for an optimum combination of multi-phasic health checkup testing obtained by considering how the health checkup accuracy changes with the number of tests (n) and kinds of combination methods (A, B, C, D and E). Methods: To find how the health checkup accuracy changes with the number of tests and type of combination method, generalized formulas as functions of the number of tests, are obtained to calculate the over-all health checkup accuracy which is defined by sensitivity ( ), specificity ( ) and odds-ratio ( ), based on the two-by-two table. Five kinds of combination methods were considered: A) Sequential tests. B) Sequential tests after changing the order in A. C) Simultaneous tests using the Believe-the-Negative Rule. D) Simultaneous tests using the Believe-the-Positive Rule. E) Simultaneous tests using the Believe-all-Positive-all-Negative Rule. Results: It was provend that combination methods A, B and C are “equivalent” for health checkup accuracy. Therefore, the five methods could be summarized into three patterns. For A, B and C:andincreased but a decreased with increasing n. For D:increased butanddecreased with n. For E:,andincreased with n. Conclusion: Health checkup accuracy of combination testing is the best in case of E, although problems exist concerning how to judge the borderline subjects.

scholarly journals Navigation Simulation of a Mecanum Wheel Mobile Robot Based on an Improved A* Algorithm in Unity3D

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2976 ◽  
Author(s):  
Yunwang Li ◽  
Sumei Dai ◽  
Yong Shi ◽  
Lala Zhao ◽  
Minghua Ding
Keyword(s):  
Mobile Robot ◽  
Effective Means ◽  
Three Dimensional ◽  
Simulation Method ◽  
Virtual Prototype ◽  
Visual Navigation ◽  
A Algorithm ◽  
Navigation Algorithm ◽  
Navigation Simulation ◽  
Mecanum Wheel

Computer simulation is an effective means for the research of robot navigation algorithms. In order to implement real-time, three-dimensional, and visual navigation algorithm simulation, a method of algorithm simulation based on secondary development of Unity3D is proposed. With this method, a virtual robot prototype can be created quickly with the imported 3D robot model, virtual joints, and virtual sensors, and then the navigation simulation can be carried out using the virtual prototype with the algorithm script in the virtual environment. Firstly, the scripts of the virtual revolute joint, virtual LiDAR sensors, and terrain environment are written. Secondly, the A* algorithm is improved for navigation in unknown 3D space. Thirdly, taking the Mecanum wheel mobile robot as an example, the 3D robot model is imported into Unity3D, and the virtual joint, sensor, and navigation algorithm scripts are added to the model. Then, the navigation is simulated in static and dynamic environments using a virtual prototype. Finally, the navigation tests of the physical robot are carried out in the physical environment, and the test trajectory is compared with the simulation trajectory. The simulation and test results validate the algorithm simulation method based on the redevelopment of Unity3d, showing that it is feasible, efficient, and flexible.

scholarly journals Optimal forecasting accuracy using Lp-norm combination

METRON ◽  
2021 ◽  
Author(s):  
Massimiliano Giacalone
Keyword(s):  
Real Data ◽  
Optimization Techniques ◽  
Combination Method ◽  
Forecast Combination ◽  
Forecasting Accuracy ◽  
Lp Norm ◽  
Combination Methods ◽  
Historical Series ◽  
Non Gaussian ◽  
Standard Regression

AbstractA well-known result in statistics is that a linear combination of two-point forecasts has a smaller Mean Square Error (MSE) than the two competing forecasts themselves (Bates and Granger in J Oper Res Soc 20(4):451–468, 1969). The only case in which no improvements are possible is when one of the single forecasts is already the optimal one in terms of MSE. The kinds of combination methods are various, ranging from the simple average (SA) to more robust methods such as the one based on median or Trimmed Average (TA) or Least Absolute Deviations or optimization techniques (Stock and Watson in J Forecast 23(6):405–430, 2004). Standard regression-based combination approaches may fail to get a realistic result if the forecasts show high collinearity in several situations or the data distribution is not Gaussian. Therefore, we propose a forecast combination method based on Lp-norm estimators. These estimators are based on the Generalized Error Distribution, which is a generalization of the Gaussian distribution, and they can be used to solve the cases of multicollinearity and non-Gaussianity. In order to demonstrate the potential of Lp-norms, we conducted a simulated and an empirical study, comparing its performance with other standard-regression combination approaches. We carried out the simulation study with different values of the autoregressive parameter, by alternating heteroskedasticity and homoskedasticity. On the other hand, the real data application is based on the daily Bitfinex historical series of bitcoins (2014–2020) and the 25 historical series relating to companies included in the Dow Jonson, were subsequently considered. We showed that, by combining different GARCH and the ARIMA models, assuming both Gaussian and non-Gaussian distributions, the Lp-norm scheme improves the forecasting accuracy with respect to other regression-based combination procedures.

scholarly journals INFECTIOUS JUMP SKILLS

2018 ◽  
Vol 4 (2) ◽  
pp. 1-10
Author(s):  
Herli Pardilla ◽  
Mulyana Mulyana ◽  
Achmad Sofyan Hanif
Keyword(s):  
Interaction Effect ◽  
Hypothesis Test ◽  
Target Population ◽  
Combination Method ◽  
P Value ◽  
Learning Method ◽  
Significant Interaction Effect ◽  
Combination Methods ◽  
The Difference ◽  
Method Group

The aim of this research is to know the difference of learning method which consists of learning method part (A1), overall method (A2) and combination method (A3) with moderator of motor ability in improving skill. The experiment was conducted by using 2x3 factorial experimental method with population which used as target population. The research was student of Physical Education University of Riau Force 2016/2017 as many as 134 which consist of 89 son and 45 daughter. Sampling was done by selecting 27% of the highest score data and 27% lowest score. Result of hypothesis test 1) difference between group of method part (A1) with group of whole method (A2) equal to t0 (A1 x A2) = -1,699, p-value = 0,096 / 2 = 0,048 <0,05, mean h0 rejected. 2) the difference between the part method group (A1) and the combination method group (A3), worth t0 (A1xA3) = -3.490, p-value = 0.001 / 2 = 0.0005 <0.05, h0 is rejected. 3) the difference between the whole method group (A2) and the combination method group (A3) worth t0 (A2xA3) = -1.791, p-value = 0.080 / 2 = 0.040 <0.05, h0 is rejected. 4) Influence Interaction (Interaction Effect) Fo (AB) = 34,349 with p-value = 0,000 <0,05 or H0 is rejected. This means there is a very significant interaction effect. 5) Differences in skill jump results between high motor and high-motor (A1B1 - A2B1) methods were 3.496, p-value = 0.001 / 2 = 0.0005 <0.05 or H0 rejected. 6) Differences in skill jump results between high motor part and high motor combination method (A1B1 - A3B1) worth = 9.568, p-value = 0,000 / 2 = 0,000 <0.05 or H0 is rejected. 7) Differences in skill jump results between the overall method with high motor and high motor combination method (A2B1 - A3B1) worth = 6,072, p-value = 0.002 / 2 = 0.001 <0.05 or H0 is rejected. 8) The difference in the results of the jump skill between the part method with the low motor and the overall method with low motor (A1B2 - A2B2) worth = 0.286, p-value = 0.680 / 2 = 0.34> 0.05 or H0 is accepted thus, no there are differences.. 9) Differences in skipjack skill results between the low-motor part and low motor combination method (A1B2 - A3B2) = -1,800, p-value = 0.079 / 2 = 0.0395 <0.05 or H0 is rejected .10) Differences in skill jump results between overall and low motor methods and low motorized combination methods (A2B2 - A3B2) = -2.086, p-value = 0.043 / 2 = 0.0215 <0.05 or H0 is rejected. difference.   Keywords: infectious jump skills, learning methods and motor skills

scholarly journals Optical metasurfaces towards multifunctionality and tunability

Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Kang Du ◽  
Hamdi Barkaoui ◽  
Xudong Zhang ◽  
Limin Jin ◽  
Qinghai Song ◽  
...  
Keyword(s):  
Research Field ◽  
Design Methods ◽  
Research Progress ◽  
Future Research ◽  
Innovative Design ◽  
Practical Applications ◽  
Light Manipulation ◽  
Optical Effects ◽  
New Material ◽  
Future Research Directions

Abstract Optical metasurfaces is a rapidly developing research field driven by its exceptional applications for creating easy-to-integrate ultrathin planar optical devices. The tight confinement of the local electromagnetic fields in resonant photonic nanostructures can boost many optical effects and offer novel opportunities for the nanoscale control of light–matter interactions. However, once the structure-only metasurfaces are fabricated, their functions will be fixed, which limits it to make breakthroughs in practical applications. Recently, persistent efforts have led to functional multiplexing. Besides, dynamic light manipulation based on metasurfaces has been demonstrated, providing a footing ground for arbitrary light control in full space-time dimensions. Here, we review the latest research progress in multifunctional and tunable metasurfaces. Firstly, we introduce the evolution of metasurfaces and then present the concepts, the basic principles, and the design methods of multifunctional metasurface. Then with more details, we discuss how to realize metasurfaces with both multifunctionality and tunability. Finally, we also foresee various future research directions and applications of metasurfaces including innovative design methods, new material platforms, and tunable metasurfaces based metadevices.

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