2017-11-23T07:04:54Z
http://ijr.kntu.ac.ir/?_action=export&rf=summon&issue=2132
International Journal of Robotics, Theory and Applications
IJR
2008-7144
2008-7144
2015
4
2
On Passive Quadrupedal Bounding with Flexible Linear Torso
Evangelos
Papadopoulos
Konstantinos
Koutsoukis
This paper studies the effect of flexible linear torso on the dynamics of passive quadruped bounding. A reduced-order passive and conservative model with linear flexible torso and springy legs is introduced. The model features extensive spine deformation during high-speed bounding, resembling those observed in a cheetah. Fixed points corresponding to cyclic bounding motions are found and calculated using numerical return map methodologies. Results show that the corresponding robot gaits and the associated performance resemble those of its natural counterparts.
Legged robots
Passive quadruped
Flexible linear torso
2015
09
01
1
8
http://ijr.kntu.ac.ir/article_12520_105ebf10e082ab5efcc5f785ca07bfb9.pdf
International Journal of Robotics, Theory and Applications
IJR
2008-7144
2008-7144
2015
4
2
Manipulation Control of a Flexible Space Free Flying Robot Using Fuzzy Tuning Approach
Payam
Zarafshan
Ali
Moosavian
Cooperative object manipulation control of rigid-flexible multi-body systems in space is studied in this paper. During such tasks, flexible members like solar panels may get vibrated that in turn may lead to some oscillatory disturbing forces on other subsystems, and consequently produces error in the motion of the end-effectors of the cooperative manipulating arms. Therefore, to design and develop capable model-based controllers for such complicated systems deriving a dynamics model is required. However, due to practical limitations and real-time implementation, the system dynamics model should require low computations. So, first to obtain a precise compact dynamics model, the Rigid-Flexible Interactive dynamics Modelling (RFIM) approach is briefly introduced. Using this approach, the system is virtually partitioned into two rigid and flexible portions, and a convenient model for control purposes is developed. Next, Fuzzy Tuning Manipulation Control (FTMC) algorithm is developed, and a Space Free-Flying Robotic (SFFR) system with flexible appendages is considered as a practical case that necessitates delicate force exertion by several end-effectors to move an object along a desired path. The SFFR system contains two cooperative manipulators, appended with two flexible solar panels. The system also includes a third and fourth arm, i.e. a turning antenna and a moving camera. To reveal the merits of the developed model-based controller, the manoeuvre is deliberately planned such that flexible modes of solar panels get stimulated due to arms motion. Obtained results show the effective performance of the proposed approach as will be discussed.
Space Free
Flying Robots
flexibility
Object Manipulation
Fuzzy control
2015
09
01
9
18
http://ijr.kntu.ac.ir/article_12521_d4b2467ad113bf63f5375dd39b9f50a3.pdf
International Journal of Robotics, Theory and Applications
IJR
2008-7144
2008-7144
2015
4
2
On The In-pipe Inspection Robots Traversing Through Elbows
Saeed
Jerban
Majid
M. Moghaddam
A general robotic mechanism was presented for in-pipe inspection oflevel pipes with varied diameter or curved pipelines. The robot employed three legs comprised of parallelogram linkages mechanism which enables adapting to various elbow joints in the piping systems. The curvatures in pipeline are the most important constraints in front of the robot through navigation process. To study the adaptability of in-pipe robots to the elbow, geometrical analysis was used to determine the minimum required diameter of an assumed resizable cylinder when it traverses through elbows. The contact points of the cylinder and the elbow are located at the medial longitudinal cross section of the elbow. However, for any designed configuration of the robots, the contact points are located at other longitudinal cross sections. For any elbow joint, a 3D space, so-called âcurved pipe limited areaâ was defined using the minimum required width along all longitudinal cross sections in elbows. The traversing robot should be adaptable to this limited area which is a function of robotâs length, pipesâ diameter and radius of curvature. A set of computer simulation was used to verify the derived analytical equations. The verified equations in this paper enable designers to confirm the dimensions of the robots for guaranteed traversing through standard elbows in pipeline. In addition to optimizing the robotâs dimensions in designing process, the proposed equations can be used for active controlling of robotâs diameter when it traverses through elbows.
In
pipe robot
inspection robot
elbow
adjustable diameter
2015
09
01
19
27
http://ijr.kntu.ac.ir/article_12522_033d679fd35f79c6b272201bb978a23b.pdf
International Journal of Robotics, Theory and Applications
IJR
2008-7144
2008-7144
2015
4
2
3D Scene and Object Classification Based on Information Complexity of Depth Data
Hamid
D. Taghirad
Alireza
Norouzzadeh
In this paper the problem of 3D scene and object classification from depth data is addressed. In contrast to high-dimensional feature-based representation, the depth data is described in a low dimensional space. In order to remedy the curse of dimensionality problem, the depth data is described by a sparse model over a learned dictionary. Exploiting the algorithmic information theory, a new definition for the Kolmogorov complexity is presented based on the Earth Moverâs Distance (EMD). Finally the classification of 3D scenes and objects is accomplished by means of a normalized complexity distance, where its applicability in practice is proved by some experiments on publicly available datasets. Also, the experimental results are compared to some state-of-the-art 3D object classification methods. Furthermore, it has been shown that the proposed method outperforms FAB-Map 2.0 in detecting loop closures, in the sense of the precision and recall.
SLAM
Loop Closure Detection
Information Theory
Kolmogorov Complexity
2015
09
01
28
35
http://ijr.kntu.ac.ir/article_12523_1dce7c5111eae75bd1ffdbc28b16da73.pdf
International Journal of Robotics, Theory and Applications
IJR
2008-7144
2008-7144
2015
4
2
Development of a Robust Observer for General Form Nonlinear System: Theory, Design and Implementation
Bahram
Tarvirdizadeh
Aghil
Yousefi-Koma
Esmaeel
Khanmirza
The problem of observer design for nonlinear systems has got great attention in the recent literature. The nonlinear observer has been a topic of interest in control theory. In this research, a modified robust sliding-mode observer (SMO) is designed to accurately estimate the state variables of nonlinear systems in the presence of disturbances and model uncertainties. The observer has a simple structure but is capable of efficient observation in the state estimation of dynamic systems. Stability of the developed observer and its convergence is proven. It is shown that the estimated states converge to the actual states in a finite time. The performance of the nonlinear observer is investigated by examining its capability in estimation of the motion of a two link rigid-flexible manipulator. The observation process of this system is complicated because of the high frequency vibration of the flexible link. Simulation results demonstrate the ability of the observer in accurately estimating the state variables of the system in the presence of structured uncertainties along with different initial conditions between the observer and the plant.
Nonlinear observer
sliding mode observer
State estimator
Robotic manipulator
Dynamic modelling
2015
09
01
36
47
http://ijr.kntu.ac.ir/article_12524_e2e6f1cda7f201bf72b055fde6d702b5.pdf
International Journal of Robotics, Theory and Applications
IJR
2008-7144
2008-7144
2015
4
2
An Efficient Algorithm for Workspace Generation of Delta Robot
Abdolreza
Gharahsofloo
Ali
Rahmani Hanzaki
Dimensional synthesis of a parallel robot may be the initial stage of its design process, which is usually carried out based on a required workspace. Since optimization of the links lengths of the robot for the workspace is usually done, the workspace computation process must be run numerous times. Hence, importance of the efficiency of the algorithm and the CPU time of the workspace computation are highlighted. This article exerts an improved numerical search method for workspace generation of a Delta robot. The algorithm is based on a methodology applied to a Hexapod manipulator somewhere else, while the improvement utilized here causes a good increase in its speed and efficiency. The results illustrate that the approach is feasible, practical, and more efficient than initial method for the generation and analysis of the workspace of the parallel manipulator, however it is done for a Delta here.
Parallel Manipulator
Delta Robot
Workspace Generation
kinematic analysis
2015
09
01
48
53
http://ijr.kntu.ac.ir/article_12525_3569104c191b35f08045e7d7b31f7551.pdf