Dynamic photogrammetric calibration of industrial robots
Research output: Contribution to journal › Conference article › Contributed › peer-review
Contributors
Abstract
Today's developments in industrial robots focus on aims like gain of flexibility, improvement of the interaction between robots and reduction of down-times. A very important method to achieve these goals are off-line programming techniques. In contrast to conventional teach-in robot programming techniques, where sequences of actions are defined step-by-step via remote control on the real object, off-line programming techniques design complete robot (inter-)action programs in a CAD/CAM environment. This poses high requirements to the geometric accuracy of a robot. While the repeatability of robot poses in the teach-in mode is often better than 0.1mm, the absolute pose accuracy potential of industrial robots is usually much worse due to tolerances, eccentricities, elasticities, play, wear-out, load, temperature and insufficient knowledge of model parameters for the transformation from poses into robot axis angles. This fact necessitates robot calibration techniques, including the formulation of a robot model describing kinematics and dynamics of the robot, and a measurement technique to provide reference data. Digital photogrammetry as an accurate, economic technique with realtime potential offers itself for this purpose. The paper analyzes the requirements posed to a measurement technique by industrial robot calibration tasks. After an overview on measurement techniques used for robot calibration purposes in the past, a photogrammetric robot calibration system based on off-the-shelf lowcost hardware components will be shown and results of pilot studies will be discussed. Besides aspects of accuracy, reliability and self-calibration in a fully automatic dynamic photogrammetric system, realtime capabilities are discussed. In the pilot studies, standard deviations of 0.05-0.25mm in the three coordinate directions could be achieved over a robot work range of 1.7 × 1.5 × 1.0 m3. The realtime capabilities of the technique allow to go beyond kinematic robot calibration and perform dynamic robot calibration as well as photogrammetric on-line control of a robot in action.
Details
Original language | English |
---|---|
Pages (from-to) | 106-112 |
Number of pages | 7 |
Journal | Proceedings of SPIE - The International Society for Optical Engineering |
Volume | 3174 |
Publication status | Published - 1997 |
Peer-reviewed | Yes |
Externally published | Yes |
Conference
Title | Videometrics V |
---|---|
Duration | 30 July 1997 |
City | San Diego, CA |
Country | United States of America |
Keywords
ASJC Scopus subject areas
Keywords
- Calibration, Dynamic 3-D measurements, Realtime, Robotics