4,419 research outputs found
Optimization of hand-to-camera calibration using geometrical interpretation of matrix equation AX = XB
No full textThe paper investigates the hand-to-camera calibration which requires
the solution of a set or simultaneous matrix equations in the rorm AX = XB. This problem is common in cases in which a manipulator moves a camera (or a sensor) Lo measure the poses of objects.
T he geometrical interpretation or t he equation suggests the best poses from which to collect data for an optimized hand-to-camera calibraLion Lo minimize the estimation error. Conditions for optimal poses location are highlighted and a new quality index Q is proposed
to represent the quality of the choice. After both a review of the problem using resulLs from Lhe literature and a theoretical
introduction, a numerical case is presented to clarify and to validate the methodology
Representation of 3D motion by projective angles
No full textThe paper describes a new laser device conceived for surface scanning and more specifically for mini robot calibrations. The system is based on a laser triangulation sensor which is moved by an extremely accurate device to collect a set of 3D points lying on surfaces. If the surfaces belong to the gripper of a robot that must be calibrated and a sufficient number of points of this gripper are collected, the pose of the robot can be measured. If the robot is moved to several different configurations and the gripper poses are measured for each of them, it is possible to reconstruct the kinematics of the robot and calibrate it. The paper presents the theory and describes the design, tests and calibration of the laser instrumentation with a focus on the first experimental results. These results are obtained in a working cell including a vision system, a 4-dof (xyz,) mini robot and a 2-dof rotating platform
OPTIMAL DESIGN AND APPLICATION OF A LOWCOST WIRE-SENSOR SYSTEM FOR THE KINEMATIC CALIBRATION OF INDUSTRIAL MANIPULATORS
No full textThe paper presents the results of a research project whose aim is investigating, from both a
theoretical and an experimental point of view, all the aspects connected to the optimal design
and use of a 6 DoF draw-wire sensors based measuring system in the kinematic calibration of
industrial robots context. One essential operation in calibration is the measurement of the pose
of the robotic gripper in a predefined set of points inside the working space. For this purpose
optical devices, like laser trackers, are usually employed due to their precision, although they
are very expensive. Therefore, the study of a low-cost measuring system and the investigation of
the reachable performances could represent a relevant outcome in the evolution of the calibration
task. With this aim the design of a wire-sensors based measuring system was developed and
applied to a six revolute degrees of freedomanthropomorphic robot. In a preliminary phase, with
the aid of simulations tools, the measuring systemwas optimized to obtain isotropic accuracy and
high sensitivity, while in the following experimental phase the same system was employed for
the kinematic calibration of the robot, achieving an accuracy lower than the robot repeatability,
which practically represents a physical limit
Experiments on Model Identification and Control of an Industrial Robot Manipulator
No full textWien, Austri
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