Extrinsic Calibration of Portable Manipulators

1992 ◽  
Author(s):  
Steven B. Shooter ◽  
Charles F. Reinholtz
Keyword(s):  
Closed Form ◽  
Nuclear Reactors ◽  
Video Feedback ◽  
Sufficient Information ◽  
Steam Generators ◽  
Extrinsic Calibration ◽  
Tool Positioning ◽  
Orthogonal Plane ◽  
Position And Orientation ◽  
Operator Control

Abstract Portable manipulators are installed for operation and then removed upon completion of their task. Typical applications of portable manipulators include the inspection of nuclear reactors, inspection and repair of nuclear steam generators and asbestos removal in buildings. In such operations, it is difficult to precisely position the manipulator at a fixed location within its workplace, yet this is critical for accurate tool positioning. It can be possible, however, to position the tool tip at several points in the environment using video feedback and manual operator control of the manipulator. This provides sufficient information to determine the position and orientation of the manipulator base frame with respect to the environment, hereafter referred to as extrinsic calibration. Following extrinsic calibration, subsequent moves of the manipulator can be automated. This paper describes a closed-form method for performing extrinsic calibration by contacting the tool to a total of six places on three orthogonal plane surfaces of reference.

scholarly journals Reliability of Sampling Inspection Schemes Applied to Replacement Steam Generators

2006 ◽  
Vol 129 (1) ◽  
pp. 109-117 ◽  
Author(s):  
Guy Roussel ◽  
Leon Cizelj
Keyword(s):  
Closed Form ◽  
Steam Generator ◽  
The State ◽  
The Other ◽  
Prior Density ◽  
Steam Generators ◽  
Numerical Examples ◽  
Closed Form Solutions ◽  
Sampling Inspection ◽  
Steam Generator Tubing

The basis for determining the size of the random sample of tubes to be inspected in replacement steam generators is revisited in this paper. A procedure to estimate the maximum number of defective tubes left in the steam generator after no defective tubes have been detected in the randomly selected inspection sample is proposed. A Bayesian estimation is used to obtain closed-form solutions for uniform, triangular, and binomial prior densities describing the number of failed tubes in steam generators. It is shown that the particular way of selecting the random inspection sample (e.g., one sample from both SG, one sample from each SG, etc.) does not affect the results of the inspection and also the information obtained about the state of the uninspected tubing, as long as the inspected steam generators belong to the same population. Numerical examples further demonstrate two possible states of the knowledge existing before the inspection of the tubing. First, virtually no knowledge about the state of the steam generator tubing before the inspection is modeled using uniform and triangular prior densities. It is shown that the knowledge about the uninspected part of the tubing strongly depends on the size of the sample inspected. Further, even small inspection samples may significantly improve our knowledge about the uninspected part. On the other hand, rather strong belief on the state of the tubing prior to the inspection is modeled using binomial prior density. In this case, the knowledge about the uninspected part of the tubing is virtually independent on the size of the sample. Furthermore, it is shown qualitatively and quantitatively that such inspection brings no additional knowledge on the uninspected part of the tubing.

Smooth Path Blending for 5-Axis Machine Tools

2020 ◽  
Author(s):  
Shingo Tajima ◽  
Burak Sencer ◽  
Hayato Yoshioka ◽  
Hidenori Shinno
Keyword(s):  
Coordinate System ◽  
Finite Impulse Response ◽  
Analytical Techniques ◽  
Computationally Efficient ◽  
Spherical Coordinate ◽  
Tool Positioning ◽  
Positioning Errors ◽  
Smooth Path ◽  
Cad Cam ◽  
Position And Orientation

Abstract 5-axis machining is widely used to manufacture complex sculptured parts, such as impellers used in jet engines. In order to machine complex part surfaces, the surface is discretized by a series of short-segmented point to point linear segments by CAD/CAM systems. Smooth non-stop motion of the tool must be interpolated along those discrete tool-paths. This paper proposes novel discrete linear path smoothing algorithms to interpolate tool position and orientation commands synchronously for 5-axis machining. Finite Impulse Response (FIR) filtering based feed profiling technique is developed to generate a smooth tool-pose trajectory with both local and global smoothing functionality. Analytical techniques are proposed to confine the blending errors within user specified tolerances. The proposed technique is computationally efficient and suitable for real-time implementation on modern NC systems. Path blending errors are defined in both the Cartesian workpiece coordinate system for tool positioning errors and the spherical coordinate system for tool orientation errors. Both position and orientation contouring errors are controlled in each coordinate system with respect to the user-defined tolerances. Simulation results validate that the proposed FIR based corner smoothing algorithm can generate smooth and non-stop trajectories for 5-axis machining. It can lead to significant cycle time gain without jeopardizing part tolerances.

Kinematics and mobility analysis of carton folds in packing manipulation based on the mechanism equivalent

2002 ◽  
Vol 216 (10) ◽  
pp. 959-970 ◽  
Author(s):  
J S Dai ◽  
J Rees Jones
Keyword(s):  
Graph Theory ◽  
Closed Form ◽  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Mobility Analysis ◽  
Mathematical Basis ◽  
Packaging Process ◽  
Kinematic Geometry ◽  
Position And Orientation

The process of erecting and closing a carton in packing manipulation is seen as a succession of folds in position and orientation from one distinct configuration to another. Permitted manipulations and changes in shape are governed by the geometry of crease lines, dimensions and profiles of the panels. The possibility for panels to fold into successive distinct configurations is determined by the kinematic geometry. This paper presents a mathematical basis which determines the mobility of distinct configurations of a carton to include the degrees of freedom dominating the manipulation and the overconstraint configurations in an erected and closed form, and proposes the kinematic analysis of a carton during packing manipulation. Use is made of the concept of line vectors and screw theory associated with graph theory. The analysis helps to explain some configurations which show how a carton can fold and opens up the way of describing manipulation in the packaging process.

scholarly journals Robotic TCF and rigid-body calibration methods

Robotica ◽  
1997 ◽  
Vol 15 (6) ◽  
pp. 633-644 ◽  
Author(s):  
Xuguang Wang ◽  
Edward Red
Keyword(s):  
Rigid Body ◽  
Closed Form ◽  
Real Time ◽  
Inverse Kinematics ◽  
Geometric Distortion ◽  
Estimation Methods ◽  
Manufacturing Cell ◽  
Calibration Methods ◽  
Position And Orientation ◽  
End Effectors

For off-line programming to work, systematic methods must be developed to account for non-ideal performance of the parts and devices in the manufacturing cell. Although much of the literature focuses on robot inaccuracy, this paper considers practical methods for the tool control frame (TCF) calibration and rigid-body compensation required to close the inverse kinematics loop for target driven tasks.In contrast to contemporary estimation methods, a closed-form, easily automated, solution is introduced for calibrating the position and orientation (pose) of orthogonal end-effectors when the distal robot joint is revolute. This paper also considers methods for measuring and compensating the small rigid-body perturbations that result from non-repeatable part delivery systems or from geometric distortion. These methods are designed to eliminate rθ error from the rigid-body prediction and can be conducted in real-time. Without accurate TCF calibration and rigid-body compensation, even the most accurate robot will fail to complete an off-line programmed task if the task tolerances are stringent.

5-Axis Tool Positioning via RFIM Strategy

2007 ◽  
Vol 10-12 ◽  
pp. 874-878 ◽  
Author(s):  
Dan Wang ◽  
Wu Yi Chen ◽  
Rui Qiu Wang
Keyword(s):  
Tilt Angle ◽  
Grid Point ◽  
Point Method ◽  
Section Method ◽  
Tool Positioning ◽  
Contact Points ◽  
New Strategy ◽  
Position And Orientation ◽  
Tool Position ◽  
Further Development

A new strategy for 5-axis NC machining called Rotate-For-Intersect Machining (RFIM) was presented in this paper. The cutter was settled by two cutter contact points and in order to obtain optimized tool position and orientation, grid point method and bi-section method ware utilized in searching cutter’s rotate angle and tilt angle. Finally the algorithm was implemented on UG platform following further development and the effectiveness of the method was validated.

Finding the Position and Orientation of a Sensor on a Robot Manipulator Using Quaternions

1991 ◽  
Vol 10 (3) ◽  
pp. 240-254 ◽  
Author(s):  
Jack C. K. Chou ◽  
M. Kamel
Keyword(s):  
Closed Form ◽  
Reference Frames ◽  
Robot Manipulator ◽  
Decomposition Analysis ◽  
Independent Set ◽  
Euler Parameters ◽  
Kinematic Equation ◽  
Singular Value Decomposition Analysis ◽  
Closed Form Solutions ◽  
Position And Orientation

The problem of finding the relative position and orientation between the reference frames of a link-mounted sensor and the link has been formulated as a kinematic equation of the form H l H x = H x H c in terms of homogeneous transformation matrices by Shiu and Ahmad (1987). In this article, normal ized quaternions (Euler parameters) are used to transform the kinematic equation into two simple and structured linear systems with rank-deficient coefficient matrices. Closed-form solutions to these systems are derived using the generalized inverse method with singular-value decomposition analysis. To obtain a unique solution, two distinct robot movements are required. This leads to an overdetermined system of equations. A criterion for selecting the independent set of equations is developed. A set of closed-form formulae for the solution of these equations are derived. The selection crite rion and the solution formulae can be easily incorporated in application programs that require the calculation of the rela tive position and orientation of the sensor.

Comparative Thermal Analyses Between Theoretical Mode and RELAP5 Code Simulation for OTSG of a Small PWR

2020 ◽  
Author(s):  
Baihui Jiang ◽  
Zhiwei Zhou ◽  
Zhaoyang Xia ◽  
Qian Sun
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Nuclear Reactors ◽  
Heat Transfer Analysis ◽  
Tube Length ◽  
Outlet Temperature ◽  
Steam Generators ◽  
Inclined Tube ◽  
Heat Transfer Calculation ◽  
Relap5 Code

Abstract Due to the low nuclear safety risk, low initial investment cost and short construction period, integrated small nuclear reactors have received wide attention from all over the world. As advanced new type of nuclear reactors, the technologies of integrated small nuclear reactors are in the process of exploration and development. Steam generators are used as the heat transfer system for energy exchange between the primary and secondary circuit in reactors, and their heat transfer analysis is very important for reactor design and development. Due to the simple structure, strong heat exchange capacity and timely load following, Once-Through Steam Generators (OTSGs) are the mainly used steam generators in the design of integrated small nuclear reactors. RELAP5/MOD4.0 is a commercial software developed by Innovative System Software, LLC for transient analysis of light water reactors (LWR). After years of development and improvement, RELAP5 has been a basic tool for analysis and calculation of various simulators of nuclear power plants. However, when RELAP5 models steam generators, only structural models related to straight pipes can be established, which is very inconvenient for the heat transfer research of Once-Through Steam Generators. In this paper, Once-Through Steam Generators with specified structural parameters are taken as the research object. The heat transfer calculation is performed on the simplified inclined tube models by RELAP5 code and the theoretical calculation of the spiral tube heat transfer models is also carried out. Comparing the steam outlet temperature on the primary and secondary sides, the heat exchange power, the average heat transfer coefficient and the tube length of different heat exchange zones under given primary and secondary side inlet fluid conditions, it is confirmed that the RELAP5 heat transfer calculation is verified for simplifying Once-Through Steam Generators with inclined tube models.

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