Source-channel coding for closed-loop control
2006 (English)Licentiate thesis, monograph (Other scientific)
Networked embedded control systems are present almost everywhere. A recent trend is to introduce wireless sensor networks in these systems, to take advantage of the added mobility and flexibility offered by wireless solutions. In such networks, the sensor observations are typically quantized and transmitted over noisy links. Concerning the problem of closed-loop control over such non-ideal communication channels, relatively few works have appeared so far. This thesis contributes to this field, by studying some fundamentally important problems in the design of joint source--channel coding and optimal control.
The main part of the thesis is devoted to joint design of the coding and control for scalar linear plants, whose state feedbacks are transmitted over binary symmetric channels. The performance is measured by a finite-horizon linear quadratic cost function. The certainty equivalence property of the studied systems is utilized, since it simplifies the overall design by separating the estimation and the control problems. An iterative optimization algorithm for training the encoder--decoder pairs, taking channel errors into account in the quantizer design, is proposed. Monte Carlo simulations demonstrate promising improvements in performance compared to traditional approaches.
Event-triggered control strategies are a promising solution to the problem of efficient utilization of communication resources. The basic idea is to let each control loop communicate only when necessary. Event-triggered and quantized control are combined for plants affected by rarely occurring disturbances. Numerical experiments show that it is possible to achieve good control performance with limited control actuation and sensor communication.
Place, publisher, year, edition, pages
Stockholm: Elektrotekniska system , 2006. , ix, 106 p.
Trita-EE, ISSN 1653-5146 ; 2006:013
optimal control, joint source--channel coding, source-channel coding, joint coding and control, certainty equivalence, linear quadratic control, stochastic control, wireless sensor network
IdentifiersURN: urn:nbn:se:kth:diva-3980OAI: oai:DiVA.org:kth-3980DiVA: diva2:10250
2006-06-02, hörsal Q2, Osquldasvägen 10, Stockholm, 14:00
Gunnarssson, Fredrik, Dr.
Skoglund, MikaelJohansson, Karl Henrik
QC 201011092006-05-192006-05-192010-11-09Bibliographically approved