scholarly journals Overcoming Kinematic Singularities for Motion Control in a Caster Wheeled Omnidirectional Robot

Robotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 133
Author(s):  
Oded Medina ◽  
Shlomi Hacohen
Keyword(s):  
Motion Control ◽  
Configuration Space ◽  
Real World ◽  
Jacobian Matrix ◽  
Kinematic Model ◽  
High Mobility ◽  
Robot Design ◽  
Novel Method ◽  
Time Propagation ◽  
Kinematic Singularities

Omnidirectional planar robots are common these days due to their high mobility, for example in human–robot interactions. The motion of such mechanisms is based on specially designed wheels, which may vary when different terrains are considered. The usage of actuated caster wheels (ACW) may enable the usage of regular wheels. Yet, it is known that an ACW robot with three actuated wheels needs to overcome kinematic singularities. This paper introduces the kinematic model for an ACW omni robot. We present a novel method to overcome the kinematic singularities of the mechanism’s Jacobian matrix by performing the time propagation in the mechanism’s configuration space. We show how the implementation of this method enables the estimation of caster wheels’ swivel angles by tracking the plate’s velocity. We present the mechanism’s kinematics and trajectory tracking in real-world experimentation using a novel robot design.

The rigid S-type cable-suspended parallel robot design, modelling and analysis

Robotica ◽  
2014 ◽  
Vol 34 (9) ◽  
pp. 1948-1960 ◽  
Author(s):  
M. Filipovic ◽  
A. Djuric ◽  
Lj. Kevac
Keyword(s):  
Jacobian Matrix ◽  
Virtual Work ◽  
Kinematic Model ◽  
Parallel Robot ◽  
Model Verification ◽  
Robot Design ◽  
Principle Of Virtual Work ◽  
Lagrange Principle ◽  
Internal Forces ◽  
The Relationship

SUMMARYThis paper presents design, modelling and analysis of the selected Rigid ropes S-type Cable-suspended Parallel Robot (RSCPR). The characteristic of this system is its geometric construction which defines the kinematic model through the Jacobian matrix. The relationship between external and internal forces is defined by the Lagrange principle of virtual work. The Jacobian matrix is directly involved in the application of the Lagrange principle of virtual work and generation of the dynamic model of the RSCPR system. Selected examples of the CPR system types are analysed and the comparison of their results is presented. The software package named ORIGI has been developed for the RSCPR model verification.

scholarly journals Improved hybrid A* path planning method for spherical mobile robot based on pendulum

2021 ◽  
Vol 18 (1) ◽  
pp. 172988142199295
Author(s):  
Ziang Zhang ◽  
Yixu Wan ◽  
You Wang ◽  
Xiaoqing Guan ◽  
Wei Ren ◽  
...  
Keyword(s):  
Mobile Robots ◽  
Common Ground ◽  
Kinematic Model ◽  
Point Contact ◽  
Shell Shape ◽  
Spherical Robot ◽  
Trajectory Tracking Control ◽  
Novel Method ◽  
Turning Radius ◽  
Spherical Mobile Robot

This article proposes a modification of hybrid A* method used for navigation of spherical mobile robots with the ability of limited partial lateral movement driven by pendulum. For pendulum-driven spherical robots with nonzero minimal turning radius, our modification helps to find a feasible and achievable path, which can be followed in line with the low time cost. Because of spherical shell shape, the robot is point contact with the ground, showing different kinematic model compared with common ground mobile robots such as differential robot and wheeled car-like robot. Therefore, this article analyzes the kinematic model of spherical robot and proposes a novel method to generate feasible and achievable paths conforming to kinematic constraints, which can be the initial value of future trajectory tracking control and further optimization. A concept of optimal robot’s minimum area for rotation is also proposed to improve search efficiency and ensure the ability of turning to any orientation by moving forward and backward in a finite number of times within limited areas.

Motion estimation in vehicular environments based on Bayesian dynamic networks

2021 ◽  
pp. 1-12
Author(s):  
Lauro Reyes-Cocoletzi ◽  
Ivan Olmos-Pineda ◽  
J. Arturo Olvera-Lopez
Keyword(s):  
Real World ◽  
Dynamic Networks ◽  
Ground Truth ◽  
Change Of Direction ◽  
Prediction Rate ◽  
Different Types ◽  
Novel Method ◽  
Comparison Of The Results ◽  
Multiple Obstacles ◽  
Real Traffic

The cornerstone to achieve the development of autonomous ground driving with the lowest possible risk of collision in real traffic environments is the movement estimation obstacle. Predicting trajectories of multiple obstacles in dynamic traffic scenarios is a major challenge, especially when different types of obstacles such as vehicles and pedestrians are involved. According to the issues mentioned, in this work a novel method based on Bayesian dynamic networks is proposed to infer the paths of interest objects (IO). Environmental information is obtained through stereo video, the direction vectors of multiple obstacles are computed and the trajectories with the highest probability of occurrence and the possibility of collision are highlighted. The proposed approach was evaluated using test environments considering different road layouts and multiple obstacles in real-world traffic scenarios. A comparison of the results obtained against the ground truth of the paths taken by each detected IO is performed. According to experimental results, the proposed method obtains a prediction rate of 75% for the change of direction taking into consideration the risk of collision. The importance of the proposal is that it does not obviate the risk of collision in contrast with related work.

scholarly journals Three Wheeled Omnidirecional Mobile Robot - Design and Implementation

2021 ◽  
Author(s):  
Darci Luiz Tomasi Junior ◽  
Eduardo Todt
Keyword(s):  
Mobile Robot ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Robot Design ◽  
Kinematic Equation ◽  
Design And Implementation ◽  
Validation Procedure ◽  
Functional Prototype ◽  
Detailed Presentation

This article presents a study of the resources necessary to providemovement and localization in three wheeled omnidirectionalrobots, through the detailed presentation of the mathematical proceduresapplicable in the construction of the inverse kinematic model,the presentation of the main hardware and software componentsused for the construction of a functional prototype, and the testprocedure used to validate the assembly.The results demonstrate that the developed prototype is functional,as well as the developed kinematic equation, given the smallerror presented at the end of the validation procedure.

scholarly journals A Novel Method based on Gaussianity and Sparsity for Signal Separation Algorithms

2017 ◽  
Vol 7 (4) ◽  
pp. 1906 ◽  
Author(s):  
Abouzid Houda ◽  
Chakkor Otman
Keyword(s):  
Independent Component Analysis ◽  
Blind Source Separation ◽  
Real World ◽  
Source Separation ◽  
Real Life ◽  
Signal Separation ◽  
Mixing Process ◽  
The Real ◽  
Input Signals ◽  
Novel Method

Blind source separation is a very known problem which refers to finding the original sources without the aid of information about the nature of the sources and the mixing process, to solve this kind of problem having only the mixtures, it is almost impossible , that why using some assumptions is needed in somehow according to the differents situations existing in the real world, for exemple, in laboratory condition, most of tested algorithms works very fine and having good performence because the  nature and the number of the input signals are almost known apriori and then the mixing process is well determined for the separation operation.  But in fact, the real-life scenario is much more different and of course the problem is becoming much more complicated due to the the fact of having the most of the parameters of the linear equation are unknown. In this paper, we present a novel method based on Gaussianity and Sparsity for signal separation algorithms where independent component analysis will be used. The Sparsity as a preprocessing step, then, as a final step, the Gaussianity based source separation block has been used to estimate the original sources. To validate our proposed method, the FPICA algorithm based on BSS technique has been used.

First- and Second-Order Kinematics-Based Constraint System Analysis and Reconfiguration Identification for the Queer-Square Mechanism

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Xi Kang ◽  
Xinsheng Zhang ◽  
Jian S. Dai
Keyword(s):  
Configuration Space ◽  
Bilinear Form ◽  
System Analysis ◽  
Kinematic Model ◽  
Second Order ◽  
Constraint System ◽  
Lie Bracket ◽  
Geometric Conditions ◽  
Reconfigurable Mechanisms ◽  
Order Constraints

Reconfiguration identification of a mechanism is essential in design and analysis of reconfigurable mechanisms. However, reconfiguration identification of a multiloop reconfigurable mechanism is still a challenge. This paper establishes the first- and second-order kinematic model in the queer-square mechanism to obtain the constraint system by using the sequential operation of the Lie bracket in a bilinear form. Introducing a bilinear form to reduce the complexity of first- and second-order constraints, the constraint system with first- and second-order kinematics of the queer-square mechanism is attained in a simplified form. By obtaining the solutions of the constraint system, six motion branches of the queer-square mechanism are identified and their corresponding geometric conditions are presented. Moreover, the initial configuration space of the mechanism is obtained.

Topology-Aware Load-Balance Schemes for Heterogeneous Graph Processing

2018 ◽  
pp. 113-143
Keyword(s):  
Parallel Processing ◽  
Complex Networks ◽  
Configuration Space ◽  
Real World ◽  
Graph Partitioning ◽  
Load Balance ◽  
Heterogeneous Computing ◽  
Graph Processing ◽  
Multi Level ◽  
Computing Approach

Inspired by the insights presented in Chapters 2, 3, and 4, in this chapter the authors present the KCMAX (K-Core MAX) and the KCML (K-Core Multi-Level) frameworks: novel k-core-based graph partitioning approaches that produce unbalanced partitions of complex networks that are suitable for heterogeneous parallel processing. Then they use KCMAX and KCML to explore the configuration space for accelerating BFSs on large complex networks in the context of TOTEM, a BSP heterogeneous GPU + CPU HPC platform. They study the feasibility of the heterogeneous computing approach by systematically studying different graph partitioning strategies, including the KCMAX and KCML algorithms, while processing synthetic and real-world complex networks.

Feedback-Driven Refinement of Mandarin Speech Recognition Result Based on Lattice Modification and Rescoring

2020 ◽  
pp. 1237-1247
Author(s):  
Xiangdong Wang ◽  
Yang Yang ◽  
Hong Liu ◽  
Yueliang Qian ◽  
Duan Jia
Keyword(s):  
Speech Recognition ◽  
Real World ◽  
Computational Cost ◽  
User Feedback ◽  
Recognition Result ◽  
Novel Method ◽  
Mandarin Speech Recognition ◽  
Recognition Errors ◽  
Dynamic Updating ◽  
Manual Correction

In real world applications of speech recognition, recognition errors are inevitable, and manual correction is necessary. This paper presents an approach for the refinement of Mandarin speech recognition result by exploiting user feedback. An interface incorporating character-based candidate lists and feedback-driven updating of the candidate lists is introduced. For dynamic updating of candidate lists, a novel method based on lattice modification and rescoring is proposed. By adding words with similar pronunciations to the candidates next to the corrected character into the lattice and then performing rescoring on the modified lattice, the proposed method can improve the accuracy of the candidate lists even if the correct characters are not in the original lattice, with much lower computational cost than that of the speech re-recognition methods. Experimental results show that the proposed method can reduce 24.03% of user inputs and improve average candidate rank by 25.31%.

scholarly journals A Novel Method for Assessing the Spatial Presence of Omnidirectional Videos: Comparing Virtual and Real World

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 183405-183413 ◽  
Author(s):  
Wenjie Zou ◽  
Wei Zhang ◽  
Jiarun Song ◽  
Fuzheng Yang ◽  
Patrick Le Callet
Keyword(s):  
Real World ◽  
Spatial Presence ◽  
Novel Method

Kinematic Modeling and Internal Motion Analysis of Proteins From a Robot Kinematics Viewpoint

2011 ◽  
Author(s):  
Keisuke Arikawa
Keyword(s):  
Jacobian Matrix ◽  
Robot Manipulator ◽  
Kinematic Model ◽  
Internal Motion ◽  
Robot Kinematics ◽  
Kinematic Modeling ◽  
Serial Link ◽  
Internal Motions ◽  
Basic Equations ◽  
External Forces

This paper discusses the kinematic modeling of proteins and the analysis of their internal motion from the viewpoint of robot kinematics. First, a kinematic model of a protein is introduced. This model consists of multiple serial link mechanisms and interaction lines (lines between alpha carbons). The protein model is regarded as a type of a robot manipulator that uses joint angles to control the lengths of the interaction lines, and the Jacobian matrix of the manipulator is derived. On the basis of this Jacobian matrix, the basic equations for calculating the deformation caused by external forces and evaluating the structural compliance of specified parts are derived. Finally, by combining the derived basic equations, we analyze the internal motions of lactoferrin and hemoglobin and compare the results with the reported measured characteristics of their internal motions. Despite the approximations by the model, the results obtained by the proposed method agree with the measured internal motion.

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