bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal turning gait of a quadruped walking robot
Authors: Cho D. J. , Kim J. H. , Gweon D. G. 
Published: March 2009

SummaryThe analysis of the gait mode is an important step for constructing a walking robot. In this study an optimal turning gait of a four-legged walking robot is proposed, which maximizes walking speed keeping walking stability larger than a certain required value. To obtain an optimal gait algorithm, for body trajectory of the robot, maximum walking speed, feasible gait modes and stability margin are analyzed for a quadruped walking robot designed in this study. The proposed gait is sufficiently flexible, as to permit crab walking, turning walking and a pure rotational walking about a robot's geometric center. The validity of the proposed gait algorithm is confirmed by many simulations.
Coordinated-motion control of heavy-duty industrial machines with redundancy
Authors: Singh N. , Zghal H. , Sepehri N. , Balakrishnan S. , Lawrence P. D. 
Published: March 2009

SummaryAn implementation of a real-time scheme suitable for coordinated-motion control of a class of teleoperated industrial machines with redundancy is presented. An efficient gradient projection technique is adopted for the numerical solution. The scheme utilizes the redundancy to avoid the joint limits by minimizing a hyperbolic function of the joint distances from the mid-range. This new performance criterion is shown to be advantageous over similar criteria; both the joint-limit avoidance capability and the resulting joint velocity profiles can be adjusted by the appropriate choice of parameters introduced in the criterion. Previous criteria are shown to be special cases of the new criterion. Furthermore, the scheme includes a novel algorithm which incorporates the bounded joint velocities. The joint motions are determined considering both the required task in terms of the desired end-effector speed and the dynamic considerations, such as hydraulic circuit interdependency and power limitations.The feasibility and effectiveness of the implementation of the scheme is first tested through simulations of a Kaiser Spyder-like excavator machine on a PC-486 micro-computer. The robustness and real-time response of the scheme are then validated on a real-time excavator-based graphics simulator interfaced to a human operator through a joystick.
Robot performance measurement and calibration using a 3D computer vision system
Authors: Preising B. , Hisa T. C. 
Published: March 2009

SummaryPresent day robot systems are manufactured to perform within industry accepted tolerances. However, to use such systems for tasks requiring high precision, various methods of robot calibration are generally required. These procedures can improve the accuracy of a robot within a small volume of the robot's workspace. The objective of this paper is to demonstrate the use of a single camera 3D computer vision system as a position sensor in order to perform robot calibration. A vision feedback scheme, termed Vision-guided Robot Control (VRC), is described which can improve the accuracy of a robot in an on-line iterative manner. This system demonstrates the advantage that can be achieved by a Cartesian space robot control scheme when end effector position/orientation are actually sensed instead ofcalculated from the kinematic equations. The degree of accuracy is determined by setting a tolerance level for each of the six robot Cartesian space coordinates. In general, a small tolerance level requires a large number of iterations in order to position the end effector, and a large tolerance level requires fewer iterations. The viability of using a vision system for robot calibration is demonstrated by experimentally showing that the accuracy of a robot can be drastically improved. In addition, the vision system can also be used to determine the repeatability and accuracy of a robot in a simple, efficient, and quick manner. Experimental work with an IBM Electric Drive Robot (EDR) and the proposed vision system produced a 97 and a 145 fold improvement in the position and orientation accuracy of the robot, respectively.
Path constrained time-optimal motion of a cooperative two robot system
Authors: Cho Hye-Kyung , Lee Bum-Hee , Ko Myoung-Sam 
Published: March 2009

SummaryThis paper presents a systematic approach to the time-optimal motion planning of a cooperative two robot system along a prescribed path. First, the minimum-time motion planning problem is formulated in a concise form by parameterizing the dynamics of the robot system through a single variable describing the path. The constraints imposed on the input actuator torques and the exerted forces on the object are then converted into those on that variable, which result in the so-called admissible region in the phase plane of the variable. Considering the load distribution problem that is also involved in the motion, we present a systematic method to construct the admissible region by employing the orthogonal projection technique and the theory of multiple objective optimization. Especially, the effects of viscous damping and state-dependent actuator bounds are incorporated into the problem formulation so that the case where the admissible region is not simply connected can be investigated in detail. The resultant time-optimal solution specifies not only the velocity profile, but also the force assigned to each robot at each instant. Physical interpretation on the characteristics of the optimal actuator torques is also included with computer simulation results.
Dynamic modeling and simulation of two cooperating structurally-flexible robotic manipulators
Authors: Krishnamurthy K. , Yang L. 
Published: March 2009

SummaryA dynamic model for two three-link cooperating structurally-flexible robotic manipulators is presented in this study. The equations of motion are derived using the extended Hamilton's principle and Galerkin's method, and must satisfy certain geometric constraints due to the closed chain formed by the two manipulators and the object. The dynamic model presented here is for the purpose of designing controllers. Therefore, a low-order model which captures all the major effects is of interest. Computer simulated results are presented for the case of moving an object along an elliptical path using the two cooperating flexible manipulators.
A semi-flexible kinematic model for serial manipulators
Authors: Cléroux Louise , Gourdeau Richard , Cloutier Guy M. 
Published: March 2009

SummaryStructural and control flexibilities affect the absolute precision of serial manipulators. A semi-flexible kinematic model is developed, to improve the absolute static precision. It expands the solid body model by incorporating a spring effect for each joint and a beam effect for each link. Simulation results confirm the adequacy of the model. The dependencies existing between the articulate posture of the manipulator, the effects of the external efforts and the gravitational load on the global structure are properly described. The identifiability of the added parameters is explored on a RR planar robot. It requires efforts and pose errors to be known in the tool frame only.
Global optimal control of redundant robot
Authors: Gotlih Karl , Troch Inge , Jezernik Karel 
Published: March 2009

SUMMARYA global optimal control algorithm was developed with the aim of finding a control which satisfies some special requirements in the sense of obtaining singular position free movement of the redundant robot mechanism. The solution of the developed global optimal control algorithm is a boundary value problem. The additional constraints in the boundary value problem were constructed with the use of an optimization process. The usefulness of the developed global optimal control algorithm is demonstrated by the example of the 3 DOFs planar redundant robot mechanism of SCARA type.
Hybrid external control for two robot coordinated motion
Authors: Perdereau Véronique , Drouin Michel 
Published: March 2009

SUMMARYIn the field of robotic applications based on the coordinated motion of two manipulators, it seems that very few control schemes work efficiently. The best way to achieve the simultaneous control of object trajectory and forces applied to it, is to implement control schemes that are extended versions of one arm hybrid force'position control. The aim of this paper is not to review all existing solutions but rather to analyze and compare them from simulation results with a new solution presented here. The control scheme is an application of the one arm hybrid external control that we had previously developed. The main results of this theory are summarized in this paper. This radically new approach for a cooperation task has some advantages compared to other methods mentioned in this paper.
Active visual sensing of the 3-D pose of a flexible object
Authors: Byun Jong-Eun , Nagatat Tadashi 
Published: March 2009

SUMMARYThis paper presents an active visual method for determining the 3-D pose of a flexible object with a hand-eye system. Some simple and effective on-line algorithms to overcome various exceptional situations in chaincoding or determine the object pose more precisely are developed. The pose of a flexible object can be easily changed because of the flexible nature and the prediction of the pose is almost impossible. A new sensing pose is computed by using the image coordinates of the points on the border line of an image window and the current pose of a hand-eye system for the cases that the flexible object is extended outside the window. In a case of exceptional overlapping, a new sensing pose is computed by using the image coordinates of four extreme image points and the current pose of the hand-eye system. Through a chaincoding process on the skeletonized images, the stereo matching problem of two images is transformed into the matching of the curvature representations of the two skeletonized images. The 3-D pose of a flexible object is computed by using the results of this matching and the camera and hand-eye parameters calibrated beforehand. The initial sensing results are used in computing a new sensing pose to determine the object more precisely.
An Advanced Robot Control Scheme Using ANN and Fuzzy Theory Based Solutions
Authors: Rudas Imre J. , Bitó János F. , Tar József K. 
Published: March 2009

SUMMARYDue to the essential development of different means of numerical computation in the last years, new prospects have been opened for realization of different advanced control methods as conventional reasoning, fuzzy rule or ANN-basedAIcontrols. However, it can clearly be seen, that each of these methods have significant technological limits making it expedient to seek compromises between the application of such methods and certain particular hardware solutions designed for a concrete problem. The aim of this paper is to show that in quite wide a range of practically important control tasks appropriate hardware solutions can be elaborated and combined with the above methods.
A 4-degrees-of-freedom microrobot with nanometer resolution
Authors: Breguet J.-M. , Renaud Ph. 
Published: March 2009

SUMMARYA new type of microrobot is described. Its simple and compact design is believed to be of promise in the microrobotics field. Stepping motion allows speeds up to 4mm/s. Resolution smaller than 10 nm is achievable. Experiments in an open-loop motion demonstrated a repeatability better than 50µm on a 10 mm displacement at an average speed of 0.25 mm/s. A position feedback based on a microvision system will be developed in order to achieve a submicron absolute position accuracy.
Local joint control in cooperating manipulator systems - force distribution and global stability
Authors: Luecke Greg R. , Gardner John F. 
Published: March 2009

SUMMARYAlmost all industrial robot applications in use today are controlled using a control law that is simple and computationally efficient, local joint error feedback. When two or more open chain manipulators cooperate to manipulate the same object - such as in mechanical grippers, walking machines, and cooperating manipulator systems - closed kinematic chain, redundantly actuated mechanisms are formed. Control approaches for this type of system focus on the more computationally intensive computed torque or inverse plant control laws, due to the concern over instability caused by the unspecified distribution of control forces in the redundant actuator space, and due to the constrained motion caused by the closed kinematic chains.
Historical perspectives and state of the art in joint force sensory feedback control of manipulation robots
Authors: Stockić Dragan , Vukobratović Miomir 
Published: March 2009

SUMMARYThe application of the joint force sensory feedback in both the gross and fine motion control of manipulation robots is considered in the paper. One of the objectives of the paper is to give a historical overview how the idea of the joint force sensory feedback has appeared and developed in the past two decades. The control schemes, which include joint torque sensory feedback, are surveyed in the paper. The main advantages of this approach are discussed: the joint torque feedback offers an elegant way to compensate for the effects of the robot dynamics without real time computation of the robot dynamics, the control schemes are robust in respect of parameter variations. Various problems regarding design and implementation of joint torque sensor are also considered. Special emphasis is given to the application of this approach in hybrid position/force control schemes.
Introduction to the special issue on robotics for health care
Authors: Kassler Michael 
Published: March 2009

Robots in the 20th century have been valued mainly for their enhancement of productivity. According to Professor Ichiro Kato of Waseda University, 21st-century robots will be valued because they enhance amenity. The development of robot systems for health care, detailed in this special issue of Robotica, is an affirmation of this forecast.Several factors have combined to cause this development, although economic factors are paramount. Industrialised countries, where robots are most likely to be used, face an ageing population-a result of lower birth rates, reduced infant mortality and increased life expectancy. This ‘ageing society' is expected to have enormous impact upon these countries’ health and social security systems which devote a large proportion of their resources to the care of older people.
Numerical robot kinematics based on stochastic and molecular simulation methods
Authors: Kastenmeier Thomas , Vesely Franz J. 
Published: March 2009

SUMMARYMultilink robot arms are geometrically similar to chain molecules. We investigate the performance of molecular simulation methods, combined with stochastic methods for optimization, when applied to problems of robotics. An efficient and flexible algorithm for solving the inverse kinematic problem for redundant robots in the presence of obstacle's (and other constraints) is suggested. This “Constrained Kinematics/Stochastic Optimization” (CKSO) method is tested on various standard problems.
Experimental evaluation of time-varying impulse shaping with a two-link flexible manipulator
Authors: Cho Jung-Keun , Park Youn-Sik 
Published: March 2009

SUMMARYIn the authors' previous paper,10 an input shaping method was presented to reduce motion-induced vibrations effectively for various classes of flexible systems. In this paper, the effectiveness of the shaping method is experimentally demonstrated with a two-link flexible manipulator systemThe manipulator for experiments includes two revolute joints and two flexible links, and moves on a vertical plane under gravity. An analytic model is developed considering the flexibility of the system and its joint stiffness in order to derive an appropriate estimation of dynamic modal properties. The input shaping method used in this work utilizes time-varying modal properties obtained from the model instead of the conventional input shaping method which employs time-invariant modal properties. A point-to-point motion is tested in order to show the effectivess of the proposed shaping method in vibration reduction during and after a given motion. The given reference trajectories are shaped to suppress the motion induced vibration. The test results demonstrate that the link vibration can be greatly suppressed during and after a motion, and the residual vibration reduction was observed more than 90% by employing this time-varying impulse shaping technique.
Application of adaptive neural network to localization of objects using pressure array transducer
Authors: Leung Anderson , Payandeh Shahram 
Published: March 2009

SUMMARYPattern recognition and object localization, using various sensors such as vision and tactile sensors, are two important areas of research in the application of robotic systems. This paper demonstrates the feasibility of using some relatively inexpensive array of pressure sensors and a neural network approach to achieve object localization and pattern recognition. The sensors that are used are force sensing resistors (FSRs), more specifically, a 16 x 16 array of FSRs. Because of the nonlinearity associated with a FSR, three possible approaches for gathering output from the sensor array are used. The neural network that is used consists of two 2-layer counterpropagation networks (CPNs). One of the CPNs is trained to recognize contact signatures of different objects placed on a fixed reference position on the sensor array.
Nonlinear regular dynamics of a single-degree robot model
Authors: Paar V. , Pavin N. , Paar N. , Novaković B. 
Published: March 2009

SUMMARYThis paper presents a mathematical model of a robot with one degree of freedom and numerical investigation of its dynamics in a particular parameter scan which is close to the upper boundary of the estimates for the parameters of rigidity and friction, while the length parameter L is treated as a free control parameter. In this L-scan the quasiperiodic and frequency locked solutions, their pattern and order of appearance are studied in the interval from the parameter range of immediate engineering significance to the point of appearance of transient chaos. In particular, a fractaltype multiple splitting of Arnold tongues is found in the parameter region bordering the range of engineering significance.
Insitumeasurement of motor electrical constants
Authors: Corke Peter I. 
Published: March 2009

SUMMARYMotor torque constant is an important parameter in modeling and controlling a robot axis. In practice this parameter can vary considerably from the manufacturer's specification, if available, and this makes it desirable to characterise individual motors. Traditional techniques require that the motor can be removed from the robot for testing, or that an elaborate technique involving weights and pulleys be employed. This paper describes a novel method for measuring the torque constant of robot servo motors insituand is based on the equivalence of motor torque and back EMF constants. It requires a very simple experimental procedure, utilizes existing axis position sensors, and eliminates effects due to static friction and joint cross coupling. A straightforward extension to this approach can provide a measurement of motor armature impedance. Experimental results obtained for a Puma 560 are discussed and compared with other published results.
Micromagnetic actuators
Authors: Arai K.I. , Honda T. 
Published: March 2009

SUMMARYRecent topics in the development of micromagneticactuators in Japan are reviewed. Electromagneticmicroactuators less than 1 mm in diameter, e.g.micromotor, and microvalves have been fabricated andtheir high performance has been demonstrated. A newtype microactuator based upon magnetostriction has alsobeen developed and has shown a large cantileverdeflection. In addition, some models of the microrobotsusing micromagnetic actuators were able to move using awireless remote power supply.
Multi-link active catheter snake-like motion
Authors: Lim Geunbae , Minami Kazuyuki , Yamamoto Keisuke , Sugihara Masahisa , Uchiyama Masaru , Esashi Masayoshi 
Published: March 2009

SUMMARYA prototype of a catheter which can move like a snake, incorporating distributed shape memory alloy actuators, is described. Since this active catheter has an instrumental navigation ability, minimally invasive diagnosis and interventional therapy will be possible. The outer diameter of the active catheter is 2.8 mm and it has many links fabricated by 3-dimensional silicon micromachining. The silicon batch process was used for the fabrication of the link to minimize assembly work. A new heating method (indirect heating) is suggested which is necessary when the JC chip is mounted on the link.
Multipath Bayesian Map Construction Model from Sonar Data
Authors: Lim Jong Hwan , Chof† Dong Woo 
Published: March 2009

SUMMARYA new model for the construction of a sonar map in a specular environment has been developed and implemented. In a real world, where most of the object surfaces are specular ones, a sonar sensor surfers from a multipath effect which results in a wrong interpretation of an object's location. To reduce this effect and hence to construct a reliable map of a robot's surroundings, a probabilistic approach based on Bayesian reasoning is adopted to both evaluation of object orientations and estimation of an occupancy probability of a cell by an object. The usefulness of this approach is illustrated with the results produced by our mobile robot equipped with ultrasonic sensors.
Dynamic world modeling for a mobile robot among moving objects
Authors: Zhang Yuefeng , Webber Robert E. 
Published: March 2009

SUMMARYA grid-based method for detecting moving objects is presented. This method involves the extension and combination of two methods: (1) the Hough Transform and (2) the Occupancy Grid method. The Occupancy Grid method forms the basis for a probabilistic estimation of the location and velocity of objects in the scene from the sensor data. The Hough Transform enables the new method to handle non-integer velocity values. A model for simulating a sonar ring is also presented. Experimental results show that this method can handle objects moving at non-integer velocities.
Experimental identification of dynamic parameters for a class of geared robots
Authors: Kozłowski Krzysztof R. , Dutkiewicz Piotr 
Published: March 2009

SUMMARYThe main objective of this paper is a presentation of an experimental identification of a non-direct drive robot and load dynamic parameters, which appear in the integral model. The last one is based on the energy theorem formulation. In the robotics literature there are not many experimental results known to the authors, concerning the identification of the dynamic parameters of different models. In order to satisfy this, the experimental system has been built around an industrial ASEA IRp-6 robot. In this paper we propose to precompute the friction characteristics which are separated in the integral model. Various aspects of the exciting trajectories are considered. It is shown how to identify the friction coefficients using a short integral model. The experimental results are presented, including comparison of the results for both integral and differential identification. The identified models are verified by computing the predicted torques and trajectories