2,881 research outputs found
Feedback Control Goes Wireless: Guaranteed Stability over Low-power Multi-hop Networks
Closing feedback loops fast and over long distances is key to emerging
applications; for example, robot motion control and swarm coordination require
update intervals of tens of milliseconds. Low-power wireless technology is
preferred for its low cost, small form factor, and flexibility, especially if
the devices support multi-hop communication. So far, however, feedback control
over wireless multi-hop networks has only been shown for update intervals on
the order of seconds. This paper presents a wireless embedded system that tames
imperfections impairing control performance (e.g., jitter and message loss),
and a control design that exploits the essential properties of this system to
provably guarantee closed-loop stability for physical processes with linear
time-invariant dynamics. Using experiments on a cyber-physical testbed with 20
wireless nodes and multiple cart-pole systems, we are the first to demonstrate
and evaluate feedback control and coordination over wireless multi-hop networks
for update intervals of 20 to 50 milliseconds.Comment: Accepted final version to appear in: 10th ACM/IEEE International
Conference on Cyber-Physical Systems (with CPS-IoT Week 2019) (ICCPS '19),
April 16--18, 2019, Montreal, QC, Canad
Control-guided Communication: Efficient Resource Arbitration and Allocation in Multi-hop Wireless Control Systems
In future autonomous systems, wireless multi-hop communication is key to
enable collaboration among distributed agents at low cost and high flexibility.
When many agents need to transmit information over the same wireless network,
communication becomes a shared and contested resource. Event-triggered and
self-triggered control account for this by transmitting data only when needed,
enabling significant energy savings. However, a solution that brings those
benefits to multi-hop networks and can reallocate freed up bandwidth to
additional agents or data sources is still missing. To fill this gap, we
propose control-guided communication, a novel co-design approach for
distributed self-triggered control over wireless multi-hop networks. The
control system informs the communication system of its transmission demands
ahead of time, and the communication system allocates resources accordingly.
Experiments on a cyber-physical testbed show that multiple cart-poles can be
synchronized over wireless, while serving other traffic when resources are
available, or saving energy. These experiments are the first to demonstrate and
evaluate distributed self-triggered control over low-power multi-hop wireless
networks at update rates of tens of milliseconds.Comment: Accepted final version to appear in: IEEE Control Systems Letter
Sensor context information for energy-efficient optimization of wireless procedures
The wide deployment of Wireless Local Area Networks (WLAN) we are witnessing today increases connectivity opportunities for mobile terminal devices, such as smartphones. However, continuous scanning for WLAN points of attachment can be a power exhausting mechanism for such battery-powered devices. These mobile devices, besides being equipped with different wireless access interfaces, are also coupled with sensors such as accelerometer, GPS, luminance and magnetic compass. In fact, sensors are increasingly being coupled into different devices and environments and are able to convey sensing information through networks into decision entities able to optimize different processes. In this paper we propose a framework where media independent sensing information is used to enhance wireless link management towards energy-efficiency. This framework enables the dissemination of sensing information towards local and remote decision entities, enhancing other processes (e.g. mobility) with sensing information in order to provide true Ambient Intelligence scenarios. We introduce this framework into a wireless management scenario able to provide energy-efficient optimal network connectivity
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