Modeling, Analysis, and Scheduling of Cluster Tools With Two Independent Arms

Abstract

Dual-armed cluster tools for semiconductor manufacturing typically have had two arms fixed in opposite directions. Recently, new cluster tool robot systems with two independent robot arms have been introduced with the expectation that the arms' flexibility will improve the throughput. However, the productivity gain has yet to be examined. Accordingly, we examine under which circumstances and the extent to which productivity gains can be achieved and how the robot task sequences should be scheduled to maximize the throughput. For this purpose, we develop a Petri net model that represents the tool behavior. We show that the wellknown swap sequence, which is known to be optimal for conventional dual-armed tools, is not always optimal. Instead, we identify two other sequences that are optimal under certain conditions. We define the workloads for each process step and the transport module to derive conditions for optimality of the sequences, based on the Petri net model and the workload. We also develop a mixed integer programming (MIP) model to determine optimal sequences among one-cyclic schedules for the cases in which the proposed sequences are not optimal. Furthermore, we analyze and demonstrate how the two independent arms can increase the throughput in comparison to a conventional dual-armed robot.Note to Practitioners-New robot technology enables reliable operation of two independent arms in cluster tools. Its operational flexibility has significant potential for tool productivity gain. Our results identify when the two independent arms are better and how their flexibility can be fully utilized. Optimal scheduling methods for the two independent arms are also given. Based on our results, tool vendors, engineers, and fabs should consider adoption of the new tool architecture.

Intelligent vehicle modeling design based on image processing

“…Essentially, the synthesis of reflective images is the superposition of two completely different light sources, so image reflective removal is a highly pathological problem. 12,13 Traditional methods use a lot of prior knowledge to remove glare. By far, the most commonly used a priori is the use of the relationship between multiple images to differentiate between the reflective area, such as flash image of the flash/focus/virtual confocal images on, before the background motion of different video sequences or by adjusting the angle of the polaroid image of the sequence, including handheld camera to users.…”

“…Since some lines (auxiliary lines) in the 3D curve model defined in this article do not exist in the image, these lines (frontal modeling lines) are not visible in most viewing angles. In order to calculate the reconstruction error, in this paper, the wheel line (8), the hub line (8), the grille profile (12), the profile line (4), the hood (1) and the modeling auxiliary line (16) 3D curve model, a total of 49 lines are excluded, and only 72 modeling characteristic line reconstruction errors are retained. For each curve, this article uses two sampling points (table 2), the starting point at the end and the error point in the middle.…”

Sliding mode nonlinear disturbance observer-based adaptive back-stepping control of a humanoid robotic dual manipulator

“…Many scholars have studied dual-arm robots, with areas of focus including modelling, control, and so on. 1,2 Tonke and Lee developed a Petri net model based on specific conditions for each step in the process and developed a transmission module to obtain optimal conditions for a sequence analysis. This method also demonstrated the two independent arms in a way that increased throughput.…”

“…This method also demonstrated the two independent arms in a way that increased throughput. 1 Shin and Kim based the validation of the human-like movements of the controller on a virtual, dynamic model to manipulate objects with humanoid robotic arms. 2 From a control perspective, trajectory tracking control in the sensorless part of the dual-arm humanoid robotic system was studied.…”