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Cyber-physical systems (CPS) increasingly require real-time, high bandwidth data communication and processing. To address this, Time Sensitive Networking (TSN) provides latency-bounded data transmission at one or more gigabits-per-second throughput. However, it does not commonly connect directly to I/O devices, such as sensors and actuators. In contrast, Universal Serial Bus (USB) is ubiquitous for device I/O, but has yet to be widely adopted for host-to-host networking. This paper considers the use of a common USB software stack for both device I/O and host-to-host communication. We compare against a system using USB for device I/O and TSN for host-level networking. Our findings show that a unified approach using USB results in reduced software complexity, simplified bus coordination, and more effective mitigation of priority inversion when transferring data across multiple bus segments. Experiments show that end-to-end latency is within expected delay bounds, and is reduced if the same USB software stack is used for all communication with a given host. This suggests that bridging challenges exist in current systems, which are solved by either extending a high-bandwidth bus such as TSN to support device I/O, or enhancing USB with improved networking capabilities.
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Under the Hood: Using Raspberry Pis and WiFis to Do More with Data
With our partners at Manylabs, we are developing Dataflow, a browser-based application that (unlike other IoT platforms) not only lets students collect and view sensor data, but also allows them to write programs that transform that data to control physical actuators. Dataflow uses Raspberry Pis as WiFi-enabled devices that can execute these control programs because they are inexpensive but powerful computers. The Pis run a client program that reads data from all USB-connected sensors, runs student programs, and sets the states of USB-connected actuators.
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- Award ID(s):
- 1640054
- PAR ID:
- 10126334
- Date Published:
- Journal Name:
- @Concord
- Volume:
- 22
- Issue:
- 2
- Page Range / eLocation ID:
- 14
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
