9,044 research outputs found
GECARO: A system for the GEometric CAlibration of RObots
International audienceThis paper presents a software package for the simulation and the practical calibration of the geometric parameters of robots. This system which is called GECARO, GEometric CAlibration of RObots, contains a large variety of methods to identify the geometric parameters of robots. GECARO is running on PC computers and developed using MATLAB; any general serial robot can be treated directly. The identifiable parameters are determined using a numerical method based on the QR decomposition, while the identification is carried out using linearized model which is solved iteratively using least squares criterion and by updating the observation matrix after each iteration
Advanced robot calibration using partial pose measurements
International audienceThe paper focuses on the calibration of serial industrial robots using partial pose measurements. In contrast to other works, the developed advanced robot calibration technique is suitable for geometrical and elastostatic calibration. The main attention is paid to the model parameters identification accuracy. To reduce the impact of measurement errors, it is proposed to use directly position measurements of several points instead of computing orientation of the end-effector. The proposed approach allows us to avoid the problem of non-homogeneity of the least-square objective, which arises in the classical identification technique with the full-pose information. The developed technique does not require any normalization and can be efficiently applied both for geometric and elastostatic identification. The advantages of a new approach are confirmed by comparison analysis that deals with the efficiency evaluation of different identification strategies. The obtained results have been successfully applied to the elastostatic parameters identification of the industrial robot employed in a machining work-cell for aerospace industry
Advanced robot calibration using partial pose measurements
The paper focuses on the calibration of serial industrial robots using
partial pose measurements. In contrast to other works, the developed advanced
robot calibration technique is suitable for geometrical and elastostatic
calibration. The main attention is paid to the model parameters identification
accuracy. To reduce the impact of measurement errors, it is proposed to use
directly position measurements of several points instead of computing
orientation of the end-effector. The proposed approach allows us to avoid the
problem of non-homogeneity of the least-square objective, which arises in the
classical identification technique with the full-pose information. The
developed technique does not require any normalization and can be efficiently
applied both for geometric and elastostatic identification. The advantages of a
new approach are confirmed by comparison analysis that deals with the
efficiency evaluation of different identification strategies. The obtained
results have been successfully applied to the elastostatic parameters
identification of the industrial robot employed in a machining work-cell for
aerospace industry
Improving the Accuracy of Industrial Robots by offline Compensation of Joints Errors
The use of industrial robots in many fields of industry like prototyping, pre-machining and end milling is limited because of their poor accuracy. Robot joints are mainly responsible for this poor accuracy. The flexibility of robots joints and the kinematic errors in the transmission systems produce a significant error of position in the level of the end-effector. This paper presents these two types of joint errors. Identification methods are presented with experimental validation on a 6 axes industrial robot, STAUBLI RX 170 BH. An offline correction method used to improve the accuracy of this robot is validated experimentally
Industry-oriented Performance Measures for Design of Robot Calibration Experiment
The paper focuses on the accuracy improvement of geometric and elasto-static
calibration of industrial robots. It proposes industry-oriented performance
measures for the calibration experiment design. They are based on the concept
of manipulator test-pose and referred to the end-effector location accuracy
after application of the error compensation algorithm, which implements the
identified parameters. This approach allows the users to define optimal
measurement configurations for robot calibration for given work piece location
and machining forces/torques. These performance measures are suitable for
comparing the calibration plans for both simple and complex trajectories to be
performed. The advantages of the developed techniques are illustrated by an
example that deals with machining using robotic manipulator
Design of Calibration Experiments for Identification of Manipulator Elastostatic Parameters
The paper is devoted to the elastostatic calibration of industrial robots,
which is used for precise machining of large-dimensional parts made of
composite materials. In this technological process, the interaction between the
robot and the workpiece causes essential elastic deflections of the manipulator
components that should be compensated by the robot controller using relevant
elastostatic model of this mechanism. To estimate parameters of this model, an
advanced calibration technique is applied that is based on the non-linear
experiment design theory, which is adopted for this particular application. In
contrast to previous works, it is proposed a concept of the user-defined
test-pose, which is used to evaluate the calibration experiments quality. In
the frame of this concept, the related optimization problem is defined and
numerical routines are developed, which allow generating optimal set of
manipulator configurations and corresponding forces/torques for a given number
of the calibration experiments. Some specific kinematic constraints are also
taken into account, which insure feasibility of calibration experiments for the
obtained configurations and allow avoiding collision between the robotic
manipulator and the measurement equipment. The efficiency of the developed
technique is illustrated by an application example that deals with elastostatic
calibration of the serial manipulator used for robot-based machining.Comment: arXiv admin note: substantial text overlap with arXiv:1211.573
Feedrate planning for machining with industrial six-axis robots
The authors want to thank Stäubli for providing the necessary information of the controller, Dynalog for its contribution to the experimental validations and X. Helle for its material contributions.Nowadays, the adaptation of industrial robots to carry out high-speed machining operations is strongly required by the manufacturing industry. This new technology machining process demands the improvement of the overall performances of robots to achieve an accuracy level close to that realized by machine-tools. This paper presents a method of trajectory planning adapted for continuous machining by robot. The methodology used is based on a parametric interpolation of the geometry in the operational space. FIR filters properties are exploited to generate the tool feedrate with limited jerk. This planning method is validated experimentally on an industrial robot
Optimization of measurement configurations for geometrical calibration of industrial robot
The paper is devoted to the geometrical calibration of industrial robots
employed in precise manufacturing. To identify geometric parameters, an
advanced calibration technique is proposed that is based on the non-linear
experiment design theory, which is adopted for this particular application. In
contrast to previous works, the calibration experiment quality is evaluated
using a concept of the user-defined test-pose. In the frame of this concept,
the related optimization problem is formulated and numerical routines are
developed, which allow user to generate optimal set of manipulator
configurations for a given number of calibration experiments. The efficiency of
the developed technique is illustrated by several examples.Comment: arXiv admin note: text overlap with arXiv:1211.610
Efficiency Improvement of Measurement Pose Selection Techniques in Robot Calibration
The paper deals with the design of experiments for manipulator geometric and
elastostatic calibration based on the test-pose approach. The main attention is
paid to the efficiency improvement of numerical techniques employed in the
selection of optimal measurement poses for calibration experiments. The
advantages of the developed technique are illustrated by simulation examples
that deal with the geometric calibration of the industrial robot of serial
architecture
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