Middleware for Automation Applications in Sensor/Actuator Networks
Sensor technology has advanced to the point where it is possible to develop a distributed, autonomous, remote sensing and actuation system made up of tiny devices. The devices can now not only sense, but can also affect their surroundings or the objects to which they are attached, thus making them particularly suitable for use in automation applications. A collection of wirelessly networked tiny devices, with sensors and actuators attached, is often referred to as an embedded networked system (EmNet). EmNets are expected to substantially augment applications such as environmental monitoring, health care, and home/commercial automation.
Use of actuators requires middleware that provides an easy way to control and organize a variety of devices into a (distributed) application. Consequently, there is a need for efficient, in-network, control (organizational) logic execution. A typical actuation application such as factory floor automation involves the management of equipment and resources in a manufacturing environment, as well as the control and monitoring of the manufacturing process. Factory floor monitoring is just one of the application domains for such middleware.
We have developed a middleware system to address the challenge of in-network actuation for automation applications. The middleware system combines a number of devices to create a declarative data flow management systems for in-network execution of distributed actuation applications.
The key features of the middleware are:
- A relational database-like system for resource constrained environments. The key features of the system are in-memory tables, queries with compile-time query plan generation and triggers. Relational model and declarative data manipulation using queries and triggers makes it easy to deal with complex conceptual model and the data flow management.
- A distributed data flow processor for resource constrained automation applications. The processors provides an SQL-like query language, shared query processing, distributed indexing and a data flow optimizer.