The limited resources of wireless devices, in terms of energy, bandwidth and computation capabilities, imposes restrictions on the design of wireless applications, such as wireless automation and wireless sensor networks. Due to the unreliability of wireless communication, where packets can be dropped or randomly delayed, the application running over the wireless network must take these problems into account. Primarily wireless control systems are studied, but many other real-time wireless applications are also considered. For example the varying delay causes stability problem for wireless closed-loop control, where e.g. the measurements are sent to the controller over a wireless network. The control problem and coordination of several control loops are also studied.
The applications in this area researched here ranges from wireless automation to wireless sensor network applications, such as structural health monitoring. The research area covers also sensor and actuator networks that are investigated from the algorithm and system level point-of-view. Research problems arise from the sensing, in-network computation and data management issues, but also coordination of actuators and networked control are considered.
Wireless Sensor and Automation Systems
In the Wireless Sensor and Automation Systems research group, we study several aspects of different wireless automation applications. We focus on, for example,
- tuning of PID controller for wireless control
- adapting the control parameters to the network operation, e.g. congestion
- simulation of wireless control systems
- event-driven control
- smart sensing
- energy efficient wireless systems
- wireless maintenance-man concept
- network protocols and applications for real-time wireless applications with strict deadlines
- real-time monitoring systems
Many of the research areas are in the field of wireless sensor networks
- indoor situation awareness
- real-time monitoring applications
- wireless structural health monitoring
Smart Wireless Embedded Services for Automation
The marriage between automation and wireless technology is excellent in tasks where the wireless system enhances the conventional automation system. By leveraging the flexibility and additional information provided by wireless sensors, a wireless embedded service (WES) system can aid in increasing the productivity, safety, maintenance, and assistance of an automation system.
For developing smart wireless embedded service systems, intelligent in-network processing and the connection to the automation system is studied. Many of the techniques mentioned above are applied in WES systems.
Wireless Sensor Systems cross-departmental research group
The cross-departmental Wireless Sensor Systems (WSS) research group is a forum for joint project and research in the field of WSS. It is a joint research group mainly between the Department of Communications and Networking and the Department of Automation and Systems Technology, and some other departmentsin Aalto University. For more information on the activity of the group see the web-page http://wsn.aalto.fi/en/.
For simulation of wireless control systems, the PiccSIM simulator has been developed. PiccSIM consists of a combination of a network simulator (ns-2) and Simulink, where the process and control algorithms are simulated. With it both the network and control are simulated at the same time, allowing one to study e.g. how specific network protocols affect the control system performance. With this simulation tool new algorithms for wireless control can be developed and tested. PiccSIM is available as open-source.
Our international research partners include SPAN lab, University of Utah, CITRIS UCLA, UC Berkeley and Yale University in the USA as well as Royal Institute of Technology (Sweden): and Automatic Control.
In Finland we cooperate with Aalto University, Department of Communications and Networking (Comnet), and University of Vaasa.
- GENSEN — Generic Sensor Network Architecture for Wireless Automation
- RELA — Reliable and Real-Time Wireless Automation
- RIWA — Reliable and Real-Time Wireless Automation
- WiSA — Wireless Sensor and Actuator Networks for Measurement and Control
- ERHE — Very Distributed Sensor and Actuator Networks
- FUCSY — Future Intelligent Wireless Communication Systems
- ICT-E — ICT of Electric distribution network
- ISMO — Intelligent Structural Health Monitoring System
- RARE — Power Control and Radio Resource Management in Wireless Multimedia Personal Communication Systems
- WISM — Wireless Sensor Systems in Indoor Situation Modeling
- SYTE — System technology for future wireless communication