Real Time Path Correction of Industrial Robots with Direct End-Effector Feedback from a Laser Tracker

2014 ◽  
Vol 7 (2) ◽  
pp. 222-228 ◽  
Author(s):  
Santiago Droll
Keyword(s):  
Real Time ◽  
Industrial Robots ◽  
Laser Tracker ◽  
End Effector ◽  
Time Path

scholarly journals An online real-time path compensation system for industrial robots based on laser tracker

2016 ◽  
Vol 13 (5) ◽  
pp. 172988141666336 ◽  
Author(s):  
Xiaojia Shi ◽  
Fumin Zhang ◽  
Xinghua Qu ◽  
Bailing Liu
Keyword(s):  
Real Time ◽  
Compensation System ◽  
Industrial Robots ◽  
Laser Tracker ◽  
Time Path

scholarly journals Robotic Surface Finishing of Curved Surfaces: Real-Time Identification of Surface Profile and Control

2018 ◽  
Author(s):  
Yalun Wen ◽  
Prabhakar R. Pagilla
Keyword(s):  
Real Time ◽  
Force Control ◽  
Surface Profile ◽  
Industrial Robots ◽  
Surface Finishing ◽  
Laser Sensor ◽  
Curved Surfaces ◽  
End Effector ◽  
Real Time Identification ◽  
Finishing Tool

An efficient strategy for robotic surface finishing of curved surfaces that includes real-time identification of the surface profile, control, and implementation is presented in this paper. Real-time identification of the surface profile in the robot base frame is accomplished by employing a proximity laser sensor mounted on the robot end-effector. This surface profile description allows us to generate trajectories for both motion and force control as it provides the surface normal at each point of the surface. Using the surface profile, a trajectory is generated that would orient the surface finishing tool to the local normal of the surface. An algorithm for simultaneous position and force control is developed for surface finishing of curved surfaces. The integrated robotic surface finishing system consists of a UR5 robot and a custom end-effector that includes a force/torque sensor, an electromechanical sander, and the proximity laser sensor. Robot Operating System (ROS) is utilized for real-time implementation, which would enable easy migration of the developed tools if other industrial robots are used. The effectiveness of the strategy is evaluated by conducting a number of experiments for flat and curved surfaces. A representative sample of results on force regulation and surface finishing are presented and discussed.

scholarly journals Real-Time Laser Tracker Compensation of Robotic Drilling and Machining

2020 ◽  
Vol 4 (3) ◽  
pp. 79 ◽  
Author(s):  
Zheng Wang ◽  
Runan Zhang ◽  
Patrick Keogh
Keyword(s):  
Real Time ◽  
Degrees Of Freedom ◽  
Low Cost ◽  
Industrial Robots ◽  
Laser Tracker ◽  
Positional Accuracy ◽  
Working Volume ◽  
Machining Test ◽  
Critical Components ◽  
Aluminum Part

Due to their flexibility, low cost and large working volume, 6-axis articulated industrial robots are increasingly being used for drilling, trimming and machining operations, especially in aerospace manufacturing. However, producing high quality components has demonstrated to be difficult, as a result of the inherent problems of robots, including low structural stiffness and low positional accuracy. These limit robotic machining to non-critical components and parts with low accuracy and surface finish requirements. Studies have been carried out to improve robotic machine capability, specifically positioning accuracy and vibration reduction. This study includes the description of the hardware, software and methodologies developed to compensate robot path errors in real time using a single three-degrees-of-freedom (DOF) laser tracker, as well as the experimental results with and without compensation. Performance tests conducted include ballbar dynamic path accuracy test, a series of drilling case studies and a machining test. The results demonstrate major improvements in path accuracy, hole position accuracy and hole quality, as well as increases in accuracy of a machined aluminum part.

scholarly journals New Method and Portable Measurement Device for the Calibration of Industrial Robots

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5919
Author(s):  
Caglar Icli ◽  
Oleksandr Stepanenko ◽  
Ilian Bonev
Keyword(s):  
Industrial Robot ◽  
Calibration Method ◽  
Industrial Robots ◽  
Laser Tracker ◽  
Calibration Model ◽  
Measuring Device ◽  
End Effector ◽  
New Device ◽  
Position Errors ◽  
Measuring Machine

This paper presents an automated calibration method for industrial robots, based on the use of (1) a novel, low-cost, wireless, 3D measuring device mounted on the robot end-effector and (2) a portable 3D ball artifact fixed with respect to the robot base. The new device, called TriCal, is essentially a fixture holding three digital indicators (plunger style), the axes of which are orthogonal and intersect at one point, considered to be the robot tool center point (TCP). The artifact contains four 1-inch datum balls, each mounted on a stem, with precisely known relative positions measured on a Coordinate Measuring Machine (CMM). The measurement procedure with the TriCal is fully automated and consists of the robot moving its end-effector in such as a way as to perfectly align its TCP with the center of each of the four datum balls, with multiple end-effector orientations. The calibration method and hardware were tested on a six-axis industrial robot (KUKA KR6 R700 sixx). The calibration model included all kinematic and joint stiffness parameters, which were identified using the least-squares method. The efficiency of the new calibration system was validated by measuring the accuracy of the robot after calibration in 500 nearly random end-effector poses using a laser tracker. The same validation was performed after the robot was calibrated using measurements from the laser tracker only. Results show that both measurement methods lead to similar accuracy improvements, with the TriCal yielding maximum position errors of 0.624 mm and mean position errors of 0.326 mm.

Industrial Robot Error Compensation Using Laser Tracker System

2008 ◽  
Vol 381-382 ◽  
pp. 579-582
Author(s):  
Jian Fei Ouyang ◽  
W. Liu ◽  
Xing Hua Qu ◽  
Y. Yan
Keyword(s):  
Real Time ◽  
Error Compensation ◽  
Industrial Robot ◽  
Laser Tracker ◽  
Geometric Errors ◽  
End Effector ◽  
Geometry Error

A technique to compensate the geometry errors of industrial robot using Laser Tracker System (LTS) has been presented in this paper. A Spherically Mounted Retro-reflector (SMR) is mounted on the end-effector of industrial robot. The positions of SMR are measured by LTS and compared with the nominal value of industrial robot to get geometry error database of robot. The updated error database, together with real-time measuring of the positions on the robot’s end-effector can be used to compensate the geometric errors of the robot. Using this technique to compensate the industrial robot, the geometry errors can be decreased from 0.1mm to 0.04mm.

scholarly journals A Kinematic Error Controller for Real-Time Kinematic Error Correction of Industrial Robots

2021 ◽  
Vol 53 ◽  
pp. 705-715
Author(s):  
Mitchell R. Woodside ◽  
Joseph Fischer ◽  
Patrick Bazzoli ◽  
Douglas A. Bristow ◽  
Robert G. Landers
Keyword(s):  
Error Correction ◽  
Real Time ◽  
Industrial Robots ◽  
Kinematic Error ◽  
Real Time Kinematic

scholarly journals Finite-Horizon Kinetic Energy Optimization of a Redundant Space Manipulator

2021 ◽  
Vol 11 (5) ◽  
pp. 2346
Author(s):  
Alessandro Tringali ◽  
Silvio Cocuzza
Keyword(s):  
Kinetic Energy ◽  
Real Time ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Computational Time ◽  
Redundant Manipulators ◽  
Space Robotics ◽  
Optimal Method ◽  
End Effector ◽  
Global Optimal

The minimization of energy consumption is of the utmost importance in space robotics. For redundant manipulators tracking a desired end-effector trajectory, most of the proposed solutions are based on locally optimal inverse kinematics methods. On the one hand, these methods are suitable for real-time implementation; nevertheless, on the other hand, they often provide solutions quite far from the globally optimal one and, moreover, are prone to singularities. In this paper, a novel inverse kinematics method for redundant manipulators is presented, which overcomes the above mentioned issues and is suitable for real-time implementation. The proposed method is based on the optimization of the kinetic energy integral on a limited subset of future end-effector path points, making the manipulator joints to move in the direction of minimum kinetic energy. The proposed method is tested by simulation of a three degrees of freedom (DOF) planar manipulator in a number of test cases, and its performance is compared to the classical pseudoinverse solution and to a global optimal method. The proposed method outperforms the pseudoinverse-based one and proves to be able to avoid singularities. Furthermore, it provides a solution very close to the global optimal one with a much lower computational time, which is compatible for real-time implementation.

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