AGVs are a key component of a flexible manufacturing system and are a proven technology for improving efficiency, safety, and quality in automotive factories. Reliability, configurability, programmability, and real-time communication capabilities are critical to successful implementation.

Challenges and goals

In this instance, the customer was planning to build up an automated warehouse system. An AGV (automated guided vehicle) system inside the factory was required to achieve this. Therefore, the mission was to provide a reliable wireless data network (Wifi technology) for the AGV system that would allow all the AGVs to be controlled from the control room.

In this application, the requirement was to transmit I/O signals from each vehicle. Even I/O traffic does not require a great deal of bandwidth, but uninterrupted communication is critical. However, a short 60- to 100-millisecond disruption in the link can cause the I/O system to stop an AGV in its tracks. As AGVs move about the plant, their wireless links must “roam” from one fixed radio to another; such roam events can cause enough delay to trip the I/O system offline.

The Jetwave series Wifi Ap employs fast roaming technology that ensures AGVs are disconnected for under 50 milliseconds while roaming from one fixed radio to the next without using a central wireless controller or any complicated network configurations.  The requirements are communication reliability: Uninterrupted and fast data communication among AGVs and the control centre is essential; trouble-shooting: When an AGV breaks down, the problem can easily be traced to its source; and finally, Wifi deployment and maintenance: Commissioning the Wifi environment does not require a lot of time and resources.

Dual band/Dual radio coverage and channel planning

Currently, a majority of the AGVs in use only support 2.4GHz Wifi. However, owing to the limited number of available channels and high interference in the 2.4GHz band, more and more AGVs are starting to support 5GHz Wifi. A future-proof Wifi network for an automated warehouse should support both 2.4GHz and 5GHz simultaneously. Jetwave Wifi Aps also support dual-band dual-concurrent operation.

There are 13 channels in the 2.4GHz band. The channel spacing is 5MHz while the channel width is 20MHz. Therefore, there are only 3 non-overlapping channels at the same time, e.g., channel 1/6/11 which are commonly used in Wifi network channel planning. The 5GHz band has a higher spectrum width compared with the 600MHz band, and it also has more channels than the 2.4GHz band. Hence making the channel planning becomes much easier. In addition, the 802.11ac standard for the 5GHz band not only supports HT20 and HT40 channel modes, but also supports HT80 channel mode.

All Korenix Jetwave Wifi series solutions support both 2.4GHz and 5GHz. Jetwave 3200 and 4200 series even have dual radio designs which can support both 2.4GHz and 5GHz individually. Under this condition, Korenix are able to offer Wifi networks with higher reliability for different AGV applications. It is one of the advantages of the Jetwave Wifi series solution.

Traditional environmental sensors are based on serial communication. Beijer IIoT employs Korenix technologies that enable 4G/LTE, Lora, and Wifi devices to convert stream communication to network communication and make the output wirelessly, saving wiring and maintenance costs. The wireless infrastructure is flexible for a long or short distance and meets all public network application requirements.

For example, Korenix offers fast roaming support averaging 50ms with Jetwave Wifi series, and the Korenix JSR (Jetwave Smart Remote) is a smartphone application that is able to display the Wifi status of all Aps and clients; and finally, the  JSM (Jetwave Smart Mapping) is a simple and easy tool designed to help end-users build up their Wifi AP and client settings.