Cluster tools for some wafer fabrication processes such as low-pressure chemical vapor deposition have strict wafer delay constraints. A wafer that completes processing in a processing chamber should leave the chamber within a specified time limit. Otherwise, the wafer suffers from severe quality troubles due to residual gases and heat within the chamber. An important engineering problem is to …
This paper explores a new method for action synchronization and control of telerobotic systems. The significance of the method is that it can effectively deal with the random time delay existing in the communication channel, such as the Internet. In addition, the result is independent of human operator. First, a novel non-time referenced action control scheme will be introduced. Instead of usin…
This paper studies a Wireless Networked Control System which utilizes the IEEE 802.11b protocol without modifications to communicate between sensors and actuators in a production line environment. OPNET simulations are used to measure the end-to-end delay from sensor to controller and then from controller to actuator. It is observed that the measured delays, including all types of data processi…
When scheduling cluster tools under wafer residency time constraints, wafer sojourn time in a processing module should be carefully controlled such that it is in a permissive range. Activity time variation often results in wafer sojourn time fluctuation and makes an originally feasible schedule infeasible. Thus, it is very important to know how the wafer sojourn time changes when activity time …
The use of multiple robots sharing a workspace can increase the productivity and the versatility of complex applications, making the existence of cells with several robots more common. On the other hand, when the robots are used to perform independent tasks in a shared workspace each one becomes a mobile obstacle for the other. Several methods have been proposed to deal with the problem of robo…