Self-triggered control of multiple loops over IEEE 802.15.4 networks

• Given the communication savings offered by self-triggered sampling, it is becoming an essential paradigm for closed-loop control over energy-constrained wireless sensor networks (WSNs). The understanding of the performance of self-triggered control systems when the feedback loops are closed over IEEE 802.15.4 WSNs is of major interest, since the communication standard IEEE 802.15.4 is the de-facto the reference protocol for energy-efficient WSNs. In this paper, a new approach to control several processes over a shared IEEE 802.15.4 network by self-triggered sampling is proposed. It is shown that the sampling time of the processes, the protocol parameters, and the scheduling of the transmissions must be jointly selected to ensure stability of the processes and energy efficiency of the network. The challenging part of the proposed analysis is ensuring stability and making an energy efficient scheduling of the state transmissions. These transmissions over IEEE 802.15.4 are allowed only at certain time slots, which are difficult to schedule when multiple control loops share the network. The approach establishes that the joint design of self-triggered samplers and the network protocol 1) ensures the stability of each loop, 2) increases the network capacity, 3) reduces the number of transmissions of the nodes, and 4) increases the sleep time of the nodes. A new dynamic scheduling problem is proposed to control each process, adapt the protocol parameters, and reduce the energy consumption. An algorithm is then derived, which adapts to any choice of the self-triggered samplers of every control loop. Numerical examples illustrate the analysis and show the benefits of the new approach.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Reglerteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Control Engineering (hsv//eng)

Nyckelord

IEEE 802.15.4

NCS

Self-triggered control

Wireless sensor network

Closed-loop control

Communication standards

Control loop

Dynamic scheduling problems

Energy efficient

Energy-constrained

Energy-Efficient Scheduling

Feed-back loop

IEEE 802.15.4 networks

Joint designs

Multiple control loops

Multiple loops

Network Capacity

Numerical example

Protocol parameters

Reference protocols

Sampling time

Sleep time

Time slots

Wireless sensor network (WSNs)

Energy efficiency

Energy utilization

Network protocols

Numerical analysis

Scheduling

Sensor nodes

Standards

Wireless sensor networks

Process control

Publikations- och innehållstyp

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