Robotic precision assembly system for microstructures

2019 ◽  
Vol 234 (8) ◽  
pp. 948-958
Author(s):  
Chao Shao ◽  
Xin Ye ◽  
Jiahui Qian ◽  
Zhijing Zhang ◽  
Dongsheng Zhu
Keyword(s):  
Calibration Method ◽  
Assembly System ◽  
Microelectromechanical System ◽  
System Calibration ◽  
Assembly Accuracy ◽  
Nondestructive Imaging ◽  
The Mean ◽  
Validation Tests ◽  
Vision Detection ◽  
Parallel Assembly

This article proposes a robotic precision assembly system for the typical parts of microstructures such as non-silicon microelectromechanical system parts. The assembly system contains three parallel assembly units and support system. In each unit, the images of the base part and target part can be obtained simultaneously from the coaxial alignment vision detection module. This article proposes a system calibration method to ensure accuracy of assembly system. Assembly experiments and accuracy validation tests are conducted. The experimental results show that the synthesizing assembly accuracy of the robotic precision assembly system can reach higher than 3 µm and the mean assembly cycle time of each part is less than 20 s, including the time for feeding and unloading parts. The robotic precision assembly system with nondestructive imaging and gripping can save on cost, achieve better quality results in less time, and greatly facilitate the precision assembly reliability and automation of microstructures.

Convenient Calibration Procedure for Structured Light Projection System

2013 ◽  
Vol 662 ◽  
pp. 777-780
Author(s):  
Wen Guo Li ◽  
Shao Jun Duan
Keyword(s):  
Relative Position ◽  
Structured Light ◽  
Calibration Method ◽  
Calibration Procedure ◽  
Shape Measurement ◽  
Projection System ◽  
System Calibration ◽  
3D Shape ◽  
3D Shape Measurement ◽  
Projector Calibration

We present a convenient calibration method for structured light projection system. The proposed clibration approach can realize 3D shape measurement without projector calibration, without system calibration, without precise linear z stage to be used, the relative position between camera and projector can be arbitrary, and the only involved device is a plane board. Experiment results validated that the accuracy of the proposed approach.

Automatic press-fit assembly of small precision interference fitting parts: armature of electro-hydraulic servo valve

2019 ◽  
Vol 39 (5) ◽  
pp. 986-998
Author(s):  
Xingyuan Wang ◽  
Zhifeng Lou ◽  
Xiaodong Wang ◽  
Yue Wang ◽  
Xiupeng Hao ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Quality Assessment ◽  
Calibration Method ◽  
Technical Problems ◽  
Content Type ◽  
Press Fit ◽  
Automatic Press ◽  
Assembly Accuracy ◽  
The Press ◽  
Methodological Guidelines

Purpose The purpose of this paper is to design an automatic press-fit instrument to realize precision assembly and connection quality assessment of a small interference fitting parts, armature. Design/methodology/approach In this paper, an automatic press-fit instrument was developed for the technical problems of reliable clamping and positioning of the armature, automatic measurement and adjustment of the attitude and evaluation of the connection quality. To compensate for the installation error of the equipment, corresponding calibration method was proposed for each module of the instrument. Assembly strategies of axial displacement and perpendicularity were also proposed to ensure the assembly accuracy. A theoretical model was built to calculate the resistant force generated by the non-contact regions and then combined with the thick-walled cylinder theory to predict the press-fit curve. Findings The calibration method and assembly strategy proposed in this paper enable the press-fit instrument to achieve good alignment and assembly accuracy. A reasonable range of press-fit curve obtained from theoretical model can achieve the connection quality assessment. Practical implications This instrument has been used in an armature assembly project. The practical results show that this instrument can assemble the armature components with complex structures automatically, accurately, in high-efficiency and in high quality. Originality/value This paper provides a technical method to improve the assembly quality of small precision interference fitting parts and provides certain methodological guidelines for precision peg-in-hole assembly.

scholarly journals Computer Vision Tool-Setting System of Numerical Control Machine Tool

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5302
Author(s):  
Bo Hou ◽  
Congpeng Zhang ◽  
Shoubo Yang
Keyword(s):  
Computer Vision ◽  
Vision System ◽  
Performance Testing ◽  
Calibration Method ◽  
Numerical Control ◽  
Cnc Machine ◽  
Control Machine Tool ◽  
System Calibration ◽  
Tool Setting ◽  
Automatic Tool

An automatic tool-setting and workpiece online detecting system was proposed to study the key technologies of next-generation intelligent vision computerized numerical control (CNC) machines. A computer vision automatic tool-setting system for a CNC machine was set up on the basis of the vision tool-setting principle. A rapid vision calibration method based on the position feedback from the CNC machine was proposed on the basis of the theory of traditional vision system calibration. The coordinate mapping relationship of the image and the CNC machine, the tool-setting mark point on the workpiece, and the tool tip were calibrated. The vision system performance testing and system calibration experiments were performed. Experimental results indicated that the time consumption was 128 ms in image processing. The precision of tool setting and measuring was less than 1 μm. The workpiece positioning and processing online detection function of the system can completely meet the requirements of visual CNC machine application, and the system has wide application prospects.

Computer Hard Disk Planeness Vision Measurement System Calibration Based on Light Plane Constraint

2013 ◽  
Vol 475-476 ◽  
pp. 63-67
Author(s):  
Rui Yin Tang ◽  
Zhou Mo Zeng ◽  
Peng Fei Li
Keyword(s):  
Nonlinear Model ◽  
Constraint Equation ◽  
Hard Disk ◽  
Calibration Method ◽  
Calibration Target ◽  
System Calibration ◽  
Vision Measurement ◽  
Light Plane ◽  
Fitting Method ◽  
Extrinsic Parameters

This paper proposed a calibration method of sheet-of-light vision measurement sensor based on light plane constraint. Through capturing 12 images of different direction from homemade circular calibration target, the center of the circle and the light stripe is extracted based on Halcon platform of Germany. The experimental results obtained the intrinsic parameters, extrinsic parameters and radial distortion coefficient of the nonlinear model. At the same time the light plane constraint equation is got based on PCA plane fitting method. The results show that the calibration method is simple and reliable, and the method does not need any auxiliary adjustment. The work laid the better foundation for hard disk planeness vision measurement.

scholarly journals CALIBRATION STUDY OF A TRIMBLE ACx4 SYSTEM FOR DIRECT GEOREFERENCING MAPPING APPLICATIONS

2018 ◽  
Vol IV-1 ◽  
pp. 45-52
Author(s):  
L. E. Filho ◽  
E. A. Mitishita
Keyword(s):  
Large Scale ◽  
Calibration Method ◽  
Relative Orientation ◽  
Aerial Images ◽  
Synthetic Image ◽  
Integrated Sensor ◽  
Full Field ◽  
System Calibration ◽  
Simultaneous Acquisition ◽  
Sensor Orientation

<p><strong>Abstract.</strong> The Trimble Aerial Camera x4 (i.e., TACx4) is a photogrammetric multi-head system manufactured by Trimble Inc.&amp;copy; in 2010. It has four cameras mounted together in the main structure allowing the simultaneous acquisition to generate a single synthetic image with much larger ground coverage. In addition, the cameras are also integrated with a GNSS/INS to perform “Direct” or “Integrated” Sensor Orientation. The main condition to obtain photogrammetric mapping products with high accuracy using a direct sensor orientation procedure is to execute a step known as “geometric system calibration”. In general, the photogrammetric multi-head system manufacturers perform this step using laboratory methods to obtain the parameters of cameras interior and relative orientation. Accurate mounting parameters (lever arms and “boresight misalignments”) are fundamental requirements to generate the synthetic image when georeferencing of images is applied. This paper shows a “full field” calibration method to perform the geometric system calibration of the TACx4 system and its evaluation for direct sensor orientation mapping applications. The developed method involves two steps using only aerial images: (1) estimation of the cameras interior and relative orientation parameters to generate the synthetic image and (2) estimation of the synthetic image interior orientation and the mounting parameters between the synthetic image and GNSS/INS reference systems using two different methods. The obtained results in the conventional photogrammetric project show that the proposed method allows performing the geometric system calibration of the TACx4 system achieving around 50<span class="thinspace"></span>cm (5 pixels) in horizontal and vertical accuracies. The obtained results can be used for large-scale mapping requirements using direct sensor orientation according to Brazilian accuracy standards.</p>

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