Wireless Communications and a Priority Access Protocol for Multiple Mobile Terminals in Factory Automation
Download as PPTX, PDF2 likes537 views
This document discusses the implementation of wireless communications and access protocols for multiple mobile terminals used in factory automation. It highlights the advantages of using a wireless local area network (WLAN) to reduce installation costs and improve communication efficiency among mobile devices like robots. The findings suggest that utilizing wireless communication can enhance operational flexibility while maintaining performance in manufacturing processes.
Wireless Communications and a Priority Access Protocol for Multiple Mobile Terminals in Factory Automation
- 1. Wireless Communications and a Priority Access Protocol for Multiple Mobile Terminals in Factory Automation SUBMITTED BY :- SANDEEP KR. MAHAWAR 2011UEC1303 EC-3
- 2. Contents INTRODUCTION WIRELESS ACCESS INFRASTRUCTURE WIRELESS ACCESS PROTOCOLS PERFORMANCE EVALUATION AND NUMERICAL RESULTS CONCLUSION
- 3. Introduction MANUFACTURING automation requires many mobile terminals. A robot is a good example of mobile terminals in manufacturing automation. Recently, multirobot systems have received much attention. The main reason for setting up a multirobot system is because two or more robots are necessary for performing manufacturing tasks, for example, carrying large objects. The problem then arises from the fact that coordination of these mobile devices becomes important. Recently, using local area network (LAN) for such operation has become an active research topic. Since 1980’s, the hardwired, token bus-based manufacturing automation protocol (MAP) network has been widely accepted for computer integrated manufacturing.
- 4. Wireless LAN A wireless local area network (WLAN) would lessen the time and cost of factory installation, restructuring and network maintenance and may allow mobile, hand-held communication users. In other words, a WLAN is a relatively low cost network of communicating control information and data to and from any mobile and fixed terminals in a factory automation application.
- 5. WIRELESS ACCESS INFRASTRUCTURE The following subsection will describe our proposed wireless access infrastructure The Current Standards Adding Wireless Strategy CDMA Techniques
- 6. The Current Standards Two widely used standards are the proposed manufacturing automation protocol (MAP) and Fieldbus (IEC TC65C). For convenience of documentation and separation of functionality, MAP is referenced on the seven-layer ISO model while Fieldbus specifications are partitioned into five-layer structures. These two standards characterize two different layer structures.
- 7. Adding Wireless Strategy The most desirable application of wireless access in factory integration is communication to and from mobile devices such as AMR’s and robots that may be clustered in islands of automation. There exist moving difficulties when these mobile devices are wired to the network. Therefore, we propose that each island can be covered by a base station. There could be several base stations in each factory floor, depending on the size of subnetworks and the number of mobile devices. Each base station controls a radio coverage area (RCA), and the RCA’s may be nonuniform and partially overlapping.
- 8. CDMA Techniques Most current WLAN products employ the code division multiple access (CDMA) techniques. The CDMA systems use spread spectrum technologies that are very suitable for indoor communication due to their capabilities in anti-multipath, antijamming, and low probability of interception and detection. In addition, the capability of allowing asynchronous, overlapped transmissions may be the key for commercial applications.
- 9. WIRELESS ACCESS PROTOCOLS Multiple access schemes used in traditional LAN’s include random access (Aloha), token passing and polling access (token bus or ring), deterministic access (TDMA/FDMA), and demand access (handshake).
- 10. PERFORMANCE EVALUATION AND NUMERICAL RESULTS we classify the traffic class into type I and type II. A type-I traffic is the traffic that carries timely information that has to reach the supervisory computer on time, otherwise, it becomes useless. This kind of traffic must have priority over the other traffic. Also, it is critical to errors, thus requires more reliable transmission. A type-II traffic, on the other hand, is less sensitive to delay (latency) and may not be critical to errors (can be retransmitted). Probability that an idle type-I unit will generate packet for transmission at next frame is Probability that an idle type-II unit will generate packet for transmission at next frame is
- 11. The average delay normalized to a frame period as The average probability of successful handshaking
- 12. CONCLUSION We can conclude that by using the wireless communication and suitable protocol, the installation and maintenance cost can be reduced without deteriorating its performance, and it also provides the flexibility in factory automation planning and restructuring.