Planar Type High-Speed Positioning Platform

1. Research Topic



< Test path >

< Application to the depaneling machine >  

 

2. Research Contents



4 planar type three degrees-of-freedom redundantly actuated parallel mechanism positioning platform is developed. It is originally developed to be used as a main platform of a new PCB depaneling system which consists of a stationary separating unit using punching system and three degrees-of-freedom positioning system. Besides the application for the PCB depaneling system, it can be applied as a main positioning platform for surface mounting machines, semiconductor industry, flat panel industry and MEMS field. The positioning platform has three degrees of freedom, of which translational axes of are in x- and y-axis with its stroke of 420 mm each. The maximum velocity is 150 m/min with its acceleration of 2g. The velocity of 150 m/min is one of the highest one achieved among the positioning platform with the stroke around 500 mm. Another unique feature of the platform is that it has one rotational axis along z-axis with its capability from -90 to +90 degrees. The main specifications of the positioning platform are shown in Table 1.



Fig.1 A photograph of the positioning platform

 

Fig.2 Rotational capability of the positioning platform (0°, -90°, +90°)

 
 

Table 1.Specifications of the positioning platform
Overall size 1,900 (L) × 1,220 (W) × 600 (H) mm
Moving platform size 230 (L) × 230 (W) × 15 (H) mm
Dexterous workspace 190 × 190 mm
Maximum velocityt 150 m/min/span>
Maximum acceleration/span> 2g (19,600 mm/sec2)
Number of axes 4 (One actuation redundancy)
Stroke of each axis 420 mm (-210 to 210 mm)
Link length 285 mm
Actuators Linear servo motors 1.5 kW (Mirae, Korea)

 
The positioning platform is based on a new symmetric 2-PPR parallel mechanism, which has four actuators. Since it has three degrees of freedom and four actuators, it has basically one actuation redundancy that is essential to achieve high-degree dexterous motions. It is crucial to eliminate the actuator singularity in the workspace from the results of kinematic analyses. The dynamics analyses for the redundantly actuated parallel mechanism that include the inverse dynamics, vibration and resultant force analyses have been performed. They helped to develop a fastest positioning platform. As a result, the positioning platform satisfies target velocity and acceleration. In addition, the mutual fighting problem of the redundantly actuated parallel mechanism is solved by a new calibration method. After calibration, the positioning accuracy is under ±0.005 mm. The detailed results are shown in Table 2.

Fig.3 A schematic of the parallel mechanism and CAD model of the positioning platform

 

Table 2. Positioning accuracy and the repeatability
Index X-axis Y-axis
Repeatability (Forward) (4σ) 3.495 micro meter 4.388 micro meter
Repeatability (Backward) (4σ) 4.027 micro meter 4.996 micro meter
Positioning accuracy 4.261 micro meter 7.698 micro meter



 


3. Publication



• Woosung In, Sungcheul Lee, Jay I. Jeong, Jongwon Kim "Design of a Planar Type High-Speed Parallel Mechanism Positioning Platform with the Capability of 180-degree Orientation" Annals of the CIRP57421-424  2008 [PDF]

• D. Jeon, K. Kim, J.I. Jeong, J.Kim "A calibration method of redundantly actuated parallel mechanism machines based on projection technique" CIRP GA 2010Pisa  8. 08 2010 [PDF]

• Sungcheul Lee, Woosung In, Sitai Kim, Jay I. Jeong and Jongwon Kim "Experimental verification of antagonistic stiffness planning for a 2-DOF planar parallel manipulator" The 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems(IROS2009)St. Louis  0. 10 2009 [PDF]

• 인우성, 김종원 "2-PPR 구조를 갖는 새로운 3자유도 평면형 병렬기구의 해석" 한국정밀공학회  1. 11 2007 [PDF]

• Woosung In, Sungjun Bae, Jongwon Kim "Analysis of a new planar 3-DOF parallel manipulator with two PPR chains" 12th IFToMM World Congress Besancon  6. 06 2007 [PDF]


4. Researcher



Ph.D : Woosung In