A new geometric approach to characterize the singularity of wheeled mobile robots

Robotica ◽  
2007 ◽  
Vol 25 (5) ◽  
pp. 627-638 ◽  
Author(s):  
Luis Gracia ◽  
Josep Tornero

SUMMARYThis research presents a new and generic geometric approach that characterizes the kinematic singularity of wheeled mobile robots. First, the kinematic models of all the common wheels are obtained: fixed, centered orientable, castor, and Swedish. Then, a procedure for generating robot kinematic models is presented based on the set of wheel equations and the null space concept. Next, two examples are developed to illustrate the nongeneric singularity characterization. In order to improve that approach, a generic and practical geometric approach is established to characterize the singularity of any kinematic model of a wheeled mobile robot (WMR). Finally, the singular configurations for many types of mobile robots are depicted employing the proposed approach.

JURNAL ELTEK ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 108
Author(s):  
Muhammad Jodi Pamenang ◽  
Indrazno Siradjuddin ◽  
Budhy Setiawan

Tujuan mendasar dari kontrol gerak mobile robot adalah untuk mengarahkan robot ke posisi yang diberikan secara acak pada ruang 2D. Mobile robot dengan roda omni memiliki sifat holonomic di mana memiliki keunggulan kelincahan dan permasalahan pengendalian gerak hanya pada sisi aktuator, sedangkan mobile robot dengan roda konvensional, memiliki permasalahan tambahan pengendalian gerak dalam ruang area operasional robot. Karenanya, robot omni lebih gesit untuk bergerak dalam konfigurasi ruang area kerja apa pun. Makalah ini menyajikan model kontrol konvergensi eksponensial berbasis model untuk mobile robot omnidirectional roda empat. Kontrol yang diusulkan menjamin penurunan kesalahan secara eksponensial dari gerakan robot ke setiap posisi robot yang diinginkan. Pembahasan meliputi model kinematik dan kontrol dari robot bergerak omnidirectional roda empat dan eksperimen simulasi yang telah dilakukan untuk memverifikasi kinerja kontrol yang meliputi lintasan robot 2D, serta nilai error atau kesalahan pada kontrol robot. Hasil dari eksperimen simulasi menunjukkan keefektifan kontrol yang diusulkan. Mobile robot telah bergerak ke posisi yang diinginkan pada garis lurus dengan tujuan robot yang akurat dan niali error atau kesalahan yang didapat ialah |0.02735| serta grafik error telah menurun secara eksponensial.   The fundamental objective of a mobile robot motion control is to navigate the robot to any given arbitrary posture in which robot 2D location and its heading are concerned. Mobile robots with omni wheels have a holonomic properties the advantage is of agility and motion control problems only on the actuator, while mobile robots with conventional wheels, have a problem of motion control the robot in task space. Therefore, the omni-wheeled mobile robots are more agile to move in any task space configuration.  This paper presents a model based exponential convergence control law for a four-wheeled omnidirectional mobile robot. The proposed control law guarantees an exponential error decay of mobile robot motion to any given desired robot posture. The kinematic model and the control law of a four-wheeled omnidirectional mobile robot are discussed. Simulation experiments have been conducted to verify the control law performances which include the 2D robot trajectory, the error signals, and the robot control signals. Results from simulation experiments show the effectiveness of the proposed control law. Mobile robot has moved to the desired position in a straight line with the aim of the robot that is accurate and the error or error obtained is | 0.02735 | and the error graph has decreased exponentially


2014 ◽  
Vol 611 ◽  
pp. 107-114 ◽  
Author(s):  
Jaromír Jezný

Provided in this article is a general overview of modeling nonholonomic mobile robots. Emphasis is given to the structural characteristics of kinematic models, taking into account the mobility restrictions caused by various links. Based on the degree of mobility and the degree of controllability it is possible to divide wheeled mobile robots into multiple groups, regardless of the robot construction and the wheels arrangement.


2015 ◽  
Vol 77 (28) ◽  
Author(s):  
M. Juhairi Aziz Safar

Holonomic and omnidirectional locomotion systems are best known for their capability to maneuver at any arbitrary direction regardless of their current position and orientation with a three degrees of freedom mobility. This paper summarizes the advancement of holonomic and omnidirectional locomotion systems for wheeled mobile robot applications and discuss the issues and challenges for future improvement.


Author(s):  
Hossein Mohammadi ◽  
Arash Haghpanah ◽  
Mohammad Eghtesad

In this paper, a novel approach for dynamics based stabilization of a four-wheel mobile robot is presented. One of the well-known and well-established approaches for stabilization of mobile robots is converting the kinematic model of the robot to a chained form. In order to extend this method to dynamic based stabilization, kinematic and dynamic subsystems of the mobile robot state-space model can be considered as two subsystems of a cascade and then feedback passivation of cascades can be utilized for stabilization of the whole system dynamics.


2017 ◽  
Vol 22 (1) ◽  
pp. 81-99 ◽  
Author(s):  
Z. Hendzel ◽  
Ł. Rykała

Abstract The work presents the dynamic equations of motion of a wheeled mobile robot with mecanum wheels derived with the use of Lagrange equations of the second kind. Mecanum wheels are a new type of wheels used in wheeled mobile robots and they consist of freely rotating rollers attached to the circumference of the wheels. In order to derive dynamic equations of motion of a wheeled mobile robot, the kinetic energy of the system is determined, as well as the generalised forces affecting the system. The resulting mathematical model of a wheeled mobile robot was generated with the use of Maple V software. The results of a solution of inverse and forward problems of dynamics of the discussed object are also published.


2013 ◽  
Vol 373-375 ◽  
pp. 231-237 ◽  
Author(s):  
Qiang Wang ◽  
Guang Tong ◽  
Xin Xing

In this paper, a new robust trajectory tracking control scheme for wheeled mobile robots without velocity measurement is proposed. In the proposed controller, the velocity observer is used to estimate the velocity of wheeled mobile robot. The dynamics of wheeled mobile robot is considered to develop the controller. The proposed controller has the following features: i) The proposed controller has good robustness performance; ii) It is easy to improve tracking performance by setting only one design parameters.


One of the major problems in the field of mobile robots is the trajectory tracking problem. There are a big number of investigations for different control strategies that have been used to control the motion of the mobile robot when the nonlinear kinematic model of mobile robots was considered. The trajectory tracking control of autonomous wheeled mobile robot in a changing unstructured environment needs to take into account different types of uncertainties. Type-1 fuzzy logic sets present limitations in handling those uncertainties while type-2 fuzzy logic sets can manage these uncertainties to give a superior performance. This paper focuses on the design of interval type-2 fuzzy like proportional-integral-derivative (PID) controller for the kinematic model of mobile robot. The firefly optimization algorithm has been used to find the best values of controller’s parameters. The aim of this controller is trying to force the mobile robot tracking a pre-defined continuous path with minimum tracking error. The Matlab simulation results demonstrate the good performance and robustness of this controller. These were confirmed by the obtained values of the position tracking errors and a very smooth velocity, especially with regards to the presence of external disturbance or change in the initial position of mobile robot. Finally, in comparison with other proposed controllers, the results of nonlinear IT2FLC PID controller outperform the nonlinear PID neural controller in minimizing the MSE for all control variables and in the robustness measure.


2001 ◽  
Author(s):  
Jenelle Armstrong Piepmeier ◽  
Peter A. Morgan

Abstract An quasi-Newton method with Jacobian estimation is used to control a mobile robot utilizing visual feedback. The method is uncalibrated, requiring no camera calibration or known robot kinematics. Given a proper task configuration, the robot can be controlled such that it follows a moving target. This paper investigates the appropriate task configurations that result in a controllable system.


Robotica ◽  
2013 ◽  
Vol 31 (6) ◽  
pp. 969-980 ◽  
Author(s):  
Yaser Maddahi ◽  
Ali Maddahi ◽  
Nariman Sepehri

SUMMARYOdometry errors, which occur during wheeled mobile robot movement, are inevitable as they originate from hard-to-avoid imperfections such as unequal wheels diameters, joints misalignment, backlash, slippage in encoder pulses, and much more. This paper extends the method, developed previously by the authors for calibration of differential mobile robots, to reduce positioning errors for the class of mobile robots having omnidirectional wheels. The method is built upon the easy to construct kinematic formulation of omnidirectional wheels, and is capable of compensating both systematic and non-systematic errors. The effectiveness of the method is experimentally investigated on a prototype three-wheeled omnidirectional mobile robot. The validations include tracking unseen trajectories, self-rotation, as well as travelling over surface irregularities. Results show that the method is very effective in improving position errors by at least 68%. Since the method is simple to implement and has no assumption on the sources of errors, it should be considered seriously as a tool for calibrating omnidirectional mobile having any number of wheels.


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