scholarly journals Fabrication of SiC Off-axis Aspheric Mirror by Using Robot Polishing

2019 ◽  
Vol 215 ◽  
pp. 09004
Author(s):  
Haitao Liu ◽  
Fengtao Yan ◽  
Wenchuan Zhao ◽  
Jieli Wu ◽  
Min Zhou
Keyword(s):  
Silicon Carbide ◽  
Industrial Robot ◽  
The Other ◽  
Surface Shape ◽  
Shape Error ◽  
Primary Mirror ◽  
Surface Polishing ◽  
Final Surface ◽  
Aspheric Mirror

Two silicon carbide (SiC) lightweight off-axis aspheric mirrors were fabricated by using robot polishing technology. One is a primary mirror with dimension 380mm×328mm, the other is a tertiary mirror with dimension 294mm×238mm. The robot polishing technology is the combination of CCOS technology and a 6-axises industrial robot. The setup of robot polishing system is discussed, and the mirror aspheric grinding, surface polishing and figuring process are reported in this paper. The final surface shape error of primary mirror is 11.4nm RMS, and the tertiary is 12.1nm RMS. The capability of off-axis aspheric mirror fabricating on robot polishing system is verified.

scholarly journals Design and Optimization for Mounting Primary Mirror with Reduced Sensitivity to Temperature Change in an Aerial Optoelectronic Sensor

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7993
Author(s):  
Meijun Zhang ◽  
Qipeng Lu ◽  
Haonan Tian ◽  
Dejiang Wang ◽  
Cheng Chen ◽  
...  
Keyword(s):  
Surface Shape ◽  
Shape Error ◽  
Temperature Decrease ◽  
Mirror Surface ◽  
Optical Performance ◽  
Uniform Temperature ◽  
Primary Mirror ◽  
Optoelectronic Sensor ◽  
Thermal Adaptability

In order to improve the image quality of the aerial optoelectronic sensor over a wide range of temperature changes, high thermal adaptability of the primary mirror as the critical components is considered. Integrated optomechanical analysis and optimization for mounting primary mirrors are carried out. The mirror surface shape error caused by uniform temperature decrease was treated as the objective function, and the fundamental frequency of the mirror assembly and the surface shape error caused by gravity parallel or vertical to the optical axis are taken as the constraints. A detailed size optimization is conducted to optimize its dimension parameters. Sensitivities of the optical system performance with respect to the size parameters are further evaluated. The configuration of the primary mirror and the flexure are obtained. The simulated optimization results show that the size parameters differently affect the optical performance and which factors are the key. The mirror surface shape error under 30 °C uniform temperature decrease effectively decreased from 26.5 nm to 11.6 nm, despite the weight of the primary mirror assembly increases by 0.3 kg. Compared to the initial design, the value of the system’s modulation transfer function (0° field angle) is improved from 0.15 to 0.21. Namely, the optical performance of the camera under thermal load has been enhanced and thermal adaptability of the primary mirror has been obviously reinforced after optimization. Based on the optimized results, a prototype of the primary mirror assembly is manufactured and assembled. A ground thermal test was conducted to verify difference in imaging quality at room and low temperature, respectively. The image quality of the camera meets the requirements of the index despite degrading.

Videooptical Surface Shape and Integrity Estimation in Robots Machining

2013 ◽  
Vol 332 ◽  
pp. 270-275 ◽  
Author(s):  
Tadeusz Mikolajczyk
Keyword(s):  
Surface Roughness ◽  
Industrial Robot ◽  
Surface Shape ◽  
Engineering System ◽  
Machined Surface ◽  
Reflectivity Method ◽  
Machining System ◽  
Grinding Tool ◽  
Smart Machining ◽  
Usb Camera

Paper shows system to surface shape and quality control in machining using industrial robot. To surface control videooptical methods were used. Surface shape was controlled using the special reverse engineering system. To surface roughness measure machined surface reflectivity method was used. Used own constructions non contact system was equipped with red laser light and USB camera. Wrist of robot was equipped with grinding tool. In paper shows some algorithms of presented processes. Shown too examples of experiments results in surface roughness measure in start end of grinding process. First trials of presented system shows possibility to build smart machining system for finishing of surface with unknown shape.

A Robotic Cell for Embedding Prefabricated Components in Extrusion-Based Additive Manufacturing

2020 ◽  
Author(s):  
Yeo Jung Yoon ◽  
Oswin G. Almeida ◽  
Aniruddha V. Shembekar ◽  
Satyandra K. Gupta
Keyword(s):  
Additive Manufacturing ◽  
Degrees Of Freedom ◽  
Robotic Manipulators ◽  
The Other ◽  
Robotic Arm ◽  
Robotic Cell ◽  
Material Extrusion ◽  
Surface Polishing ◽  
Pick And Place ◽  
6 Degrees Of Freedom

Abstract By attaching a material extrusion system to a robotic arm, we can deposit materials onto complex surfaces. Robotic manipulators can also maximize the task utility by performing other tasks such as assembly or surface polishing when they are not in use for the AM process. We present a robotic cell for embedding prefabricated components in extrusion-based AM. The robotic cell consists of two 6 degrees of freedom (DOF) robots, an extrusion system, and a gripper. One robot is used for printing a part, and the other robot takes a support role to pick and place the prefabricated component and embed it into the part being printed. After the component is embedded, AM process resumes, and the material is deposited onto the prefabricated components and previously printed layers. We illustrate the capabilities of the system by fabricating three objects.

Finite Element Analysis for Surface Shape Deformation of Photo-Electronic Theodolite Primary Mirror

2008 ◽  
Vol 28 (4) ◽  
pp. 756-763 ◽  
Author(s):  
谭凡教 Tan Fanjiao ◽  
乔彦峰 Qiao Yanfeng ◽  
李耀彬 Li Yaobin ◽  
高慧斌 Gao Huibin ◽  
刘旨春 Liu Zhichun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Surface Shape ◽  
Shape Deformation ◽  
Element Analysis ◽  
Primary Mirror

scholarly journals A High-Efficiency Three-Level ANPC Inverter Based on Hybrid SiC and Si Devices

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1159 ◽  
Author(s):  
Zhijian Feng ◽  
Xing Zhang ◽  
Jianing Wang ◽  
Shaolin Yu
Keyword(s):  
Silicon Carbide ◽  
High Efficiency ◽  
The Other ◽  
Switching Frequency ◽  
Parallel Operation ◽  
Switching Loss ◽  
Hybrid Scheme ◽  
Excellent Performance ◽  
Switching Losses ◽  
The Cost

Silicon carbide (SiC) devices have excellent performance, such as higher switching frequency and lower switching loss compared with traditional silicon (Si) devices. The application of SiC devices in inverters can achieve higher efficiency and power density. In recent years, the production process of SiC devices has become more mature, but the cost is still several times that of traditional Si devices. In order to balance cost and efficiency, replacing only some of the Si devices with SiC devices in a topology is a better choice. This paper proposed a high-efficiency hybrid active neutral point clamped (ANPC) three-level inverter which has only two SiC devices and the other devices are Si devices. A specific modulation strategy was applied to concentrate switching losses on the SiC devices and reduce the on-state loss through parallel operation during freewheeling intervals. Theoretical efficiency curves and experimental verification of the proposed hybrid scheme with Si-only and SiC-only schemes were carried out.

scholarly journals Comparative study of the surface roughness of Ormocer-based and conventional composites

2003 ◽  
Vol 11 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Leonardo Gonçalves Cunha ◽  
Roberta Caroline Bruschi Alonso ◽  
Paulo Henrique dos Santos ◽  
Mário Alexandre Coelho Sinhoreti
Keyword(s):  
Surface Roughness ◽  
Comparative Study ◽  
Statistical Difference ◽  
The Other ◽  
Initial Surface ◽  
Resin Composites ◽  
Metallic Mold ◽  
Tukey Test ◽  
Final Surface ◽  
Before And After

The aim of this study was to evaluate the surface roughness of two Ormocer-based resin composites before and after mechanical toothbrushing. The study compared the brands Admira and Definite with composites based on conventional monomer systems (Bis-GMA, Bis-EMA, UEDMA e TEGDMA), Z250 and A110. Eight samples of each material with 4mm in diameter and 2mm in height were prepared using a metallic mold. After 24 hours they were polished and examined with a profilometer for measurement of the initial surface roughness (Ra, mm) before mechanical toothbrushing (30,000 cycles). After toothbrushing, the samples were taken to the profilometer once again to check the final surface roughness. The results were submitted to ANOVA and Tukey test (5%). The Admira composite presented a higher mean of surface roughness before toothbrushing (0.132mm), with a statistical difference from the composite A110 (0.082mm). Definite (0.110mm) and Z250 (0.105mm) composites showed no differences between themselves or among the other composites. No statistical differences were observed after toothbrushing between the composites Definite (0.178mm), Z250 (0.187mm), Admira (0.181mm), and A110 (0.193mm). All composites showed a statistically significant increase in the surface roughness after toothbrushing.

Forming Type Rapid Prototyping Development - Error Compensation with Shape Measurement -

2008 ◽  
Vol 2 (6) ◽  
pp. 462-467 ◽  
Author(s):  
Hidetake Tanaka ◽  
◽  
Naoki Asakawa ◽  
Masatoshi Hirao ◽  
Keyword(s):  
Rapid Prototyping ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Error Compensation ◽  
Industrial Robot ◽  
Shape Measurement ◽  
Shape Error ◽  
Range Finder ◽  
Tool Positioning ◽  
Computer Aided

This study deals with the automation of metal hammering using an industrial robot and trial development of rapid prototyping of sheet metal forming. Computer-aided manufacturing (CAM) takes into account feedback considering tool positioning by using a range finder to improve depth and shape error at workpiece corners. Experimental results confirmed that our proposal reduces shape error through tool positioning optimization.

Servo System Design Considering Low-Stiffness of Robot

1996 ◽  
Vol 8 (3) ◽  
pp. 252-258 ◽  
Author(s):  
Akira Shimada ◽  
Keyword(s):  
System Design ◽  
Design Method ◽  
Industrial Robot ◽  
Servo System ◽  
The Other ◽  
Special Relation ◽  
Practical Design ◽  
Single Moment ◽  
Industrial Use ◽  
Low Stiffness

This paper describes the practical design method of an advanced servo system for industrial robot manipulators, where it includes a disturbance and velocity observer. It is first assumed that the feature on frequency response of the robot is approximated to the feature of two-mass mechanism. Actually this is confirmed by some experiments. On the other hand, it is insisted that the actual servo system should be simple for industrial use. The observer is designed for the load which has the feature of single moment of inertia. Based on the assumption that there is a difference between these features, it is introduced that the servo system can be effectively used if only the qualified gains are selected considering lowstiffness. The special relation between the frequency analysis and the pole allocations are then shown, and Finally the experimental results are introduced.

Effect of the measuring mirror surface shape error on ruled groove straightness and the grating diffraction wavefront

2020 ◽  
Vol 59 (27) ◽  
pp. 8465
Author(s):  
Xiaotao Mi ◽  
Shanwen Zhang ◽  
Xiangdong Qi ◽  
Haili Yu ◽  
Hongzhu Yu ◽  
...  
Keyword(s):  
Surface Shape ◽  
Shape Error ◽  
Mirror Surface ◽  
Grating Diffraction
Sign in / Sign up

Export Citation Format

Share Document