High-accuracy visual/PSD hybrid servoing of robotic manipulator

Journal of Applied Mathematics

et al. 2014

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Joint offset calibration is one of the most important methods to improve the positioning accuracy for industrial robots. This paper presents an efficient method to calibrate industrial robot joint offset. The proposed method mainly relies on a laser pointer mounted on the robot end-effector and a position sensitive device (PSD) located in the work space arbitrarily. A vision based control was employed to aid the laser beam shooting at the center of PSD surface from several initial robot postures. For each shoot, the laser beam was a line in space which can be determined by the robot joint angles and their offsets which were recorded when the laser beam was brought to the center of the PSD surface. Therefore, there are several lines in space parameterized by robot joint offsets only and all these lines were constrained by the same point, that is, the center of the PSD surface. Consequently, an optimization model was formulated and the Levenberg-Marquardt (LM) algorithm was employed to identify the joint offsets. The developed calibration system was implemented on an ABB industrial robot IRB1600 successfully. And the joint offsets of this robot can be calibrated within 6 minutes.

Section: Line-based and Single Point Constraint Approachmentioning

confidence: 99%

mentioning

confidence: 99%

Developing an Efficient Calibration System for Joint Offset of Industrial Robots

Gao

Journal of Applied Mathematics

et al. 2014

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“…The calibration method represented in [9] relies mainly upon a laser pointer attached on the end-effector of a robot and single PSD. The calibration procedure is aiming a laser beam from the laser pointer at the same point from various positions and orientations by using hybrid visual/PSD servoing [11], as shown in Fig. 4.…”

Section: B Uncalibratied Laser Toolmentioning

confidence: 99%

Development and sensitivity analysis of a portable calibration system for joint offset of industrial robot

2009 IEEE/RSJ International Conference on Intelligent Robots and Systems

Zhao

et al. 2009

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This paper describes our updated system for industrial robot joint offset calibration. The system consists of an IRB1600 industrial robot, a laser tool attached to the robot's end-effector, a portable position-sensitive device (PPD), and a PC based controller. By aiming the laser spot to the center of position-sensitive-detector (PSD) on the PPD with different robot configurations, the developed system ideally implements our proposed calibration method called the virtual line-based single-point constraint approach. However, unlike our previous approach, the calibration method is extended to identify the offset parameters with an uncalibrated laser tool. The position errors of the PPD and the sensitivities of error in the PSD plane to the variation of joint angles are analyzed. Two different robot configuration patterns are compared by implementing the calibration method. Both simulation and real experimental results are consistent with the mathematical analysis. Experimental results with small (10 -3 -10 -2 ) mean and standard deviation of parameters error verify the effectiveness of both the sensitivity analysis and the developed system.

“…Since the employed IBVS method has been developed very well, this article will mainly focus on presenting the developed PSD guided servoing method. Our previous work (Liu et al 2008b) presents the combination between the PSD servoing and visual servoing for achieving a hybrid servo control.…”

Section: Nomenclaturementioning

confidence: 99%

“…Through extensive experiments, the developed system has verified that it has the properties such as low cost, high precision, and rapid response. The system can be used to compensate for the disadvantages of the vision servoing methods as well as effectively combined with the well-developed visual servoing system to form a powerful hybrid servo control system (Liu et al 2008b). In addition, the PSDGS system can be further developed to be a portable and affordable tool for calibration of industrial robots.…”

Section: Nomenclaturementioning

confidence: 99%

Position-Sensitive Detector (PSD) Guided Servoing Method for Industrial Robot Calibration

International Journal of Optomechatronics

Shen

et al. 2009

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This article presents our recently developed position-sensitive detector (PSD) guided servoing system for precise localization of industrial robots. The system is portable and affordable, and can position robot precisely so as to benefit further research on the calibration applications of industrial robots. To achieve highly precise position feedback, we have employed a high performance lateral-effect PSD with a resolution of 0.5 m. Based on the system kinematics and dynamics, a PSD guided servo (PSDGS) control method is then developed and simplified to be a planar motion control approach in which an on-line estimation of the transformation matrix between the PSD object and the robot base is applied. The experiments have been implemented on an ABB industrial robot IRB1600. The achieved results demonstrate that the mean localization precision of the industrial robot using the developed PSDGS method is totally better than 20 m.