Limits...
Aperiodic linear networked control considering variable channel delays: application to robots coordination.

Santos C, Espinosa F, Santiso E, Mazo M - Sensors (Basel) (2015)

Bottom Line: One of the main challenges in wireless cyber-physical systems is to reduce the load of the communication channel while preserving the control performance.This way, the controller manages the usage of the wireless channel in order to reduce the channel delay and to improve the availability of the communication resources.Implementation results applying the aperiodic linear control laws on four P3-DX robots are also included.

View Article: PubMed Central - PubMed

Affiliation: Electronics Department, Polytechnics School, University of Alcala, Campus Universitario, Ctra. Madrid-Barcelona, Km. 33,600, 28871. Alcalá de Henares, Madrid, Spain. carlos.santos@depeca.uah.es.

ABSTRACT
One of the main challenges in wireless cyber-physical systems is to reduce the load of the communication channel while preserving the control performance. In this way, communication resources are liberated for other applications sharing the channel bandwidth. The main contribution of this work is the design of a remote control solution based on an aperiodic and adaptive triggering mechanism considering the current network delay of multiple robotics units. Working with the actual network delay instead of the maximum one leads to abandoning this conservative assumption, since the triggering condition is fixed depending on the current state of the network. This way, the controller manages the usage of the wireless channel in order to reduce the channel delay and to improve the availability of the communication resources. The communication standard under study is the widespread IEEE 802.11g, whose channel delay is clearly uncertain. First, the adaptive self-triggered control is validated through the TrueTime simulation tool configured for the mentioned WiFi standard. Implementation results applying the aperiodic linear control laws on four P3-DX robots are also included. Both of them demonstrate the advantage of this solution in terms of network accessing and control performance with respect to periodic and non-adaptive self-triggered alternatives.

No MeSH data available.


Related in: MedlinePlus

Relation between the network delay and the σ values.
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f4-sensors-15-12454: Relation between the network delay and the σ values.

Mentions: Figure 4 depicts the key aspects to select the σ value according to the current network delay. The first step checked by the designer is to find the maximum allowable delay (τstable); all of the delays have to be smaller than this one, assuring stability Next, the number of delay zones are fixed, and with them, the corresponding partial limit delay τi is known. Then, the maximum σ value concerning each zone is calculated. Finally, the designer chooses a σ value taking into account that it must be equal to or lower than the maximum one previously calculated. For example: σi ∈]0, σiMAX] where tmin(σiMAX) = τi.


Aperiodic linear networked control considering variable channel delays: application to robots coordination.

Santos C, Espinosa F, Santiso E, Mazo M - Sensors (Basel) (2015)

Relation between the network delay and the σ values.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507601&req=5

f4-sensors-15-12454: Relation between the network delay and the σ values.
Mentions: Figure 4 depicts the key aspects to select the σ value according to the current network delay. The first step checked by the designer is to find the maximum allowable delay (τstable); all of the delays have to be smaller than this one, assuring stability Next, the number of delay zones are fixed, and with them, the corresponding partial limit delay τi is known. Then, the maximum σ value concerning each zone is calculated. Finally, the designer chooses a σ value taking into account that it must be equal to or lower than the maximum one previously calculated. For example: σi ∈]0, σiMAX] where tmin(σiMAX) = τi.

Bottom Line: One of the main challenges in wireless cyber-physical systems is to reduce the load of the communication channel while preserving the control performance.This way, the controller manages the usage of the wireless channel in order to reduce the channel delay and to improve the availability of the communication resources.Implementation results applying the aperiodic linear control laws on four P3-DX robots are also included.

View Article: PubMed Central - PubMed

Affiliation: Electronics Department, Polytechnics School, University of Alcala, Campus Universitario, Ctra. Madrid-Barcelona, Km. 33,600, 28871. Alcalá de Henares, Madrid, Spain. carlos.santos@depeca.uah.es.

ABSTRACT
One of the main challenges in wireless cyber-physical systems is to reduce the load of the communication channel while preserving the control performance. In this way, communication resources are liberated for other applications sharing the channel bandwidth. The main contribution of this work is the design of a remote control solution based on an aperiodic and adaptive triggering mechanism considering the current network delay of multiple robotics units. Working with the actual network delay instead of the maximum one leads to abandoning this conservative assumption, since the triggering condition is fixed depending on the current state of the network. This way, the controller manages the usage of the wireless channel in order to reduce the channel delay and to improve the availability of the communication resources. The communication standard under study is the widespread IEEE 802.11g, whose channel delay is clearly uncertain. First, the adaptive self-triggered control is validated through the TrueTime simulation tool configured for the mentioned WiFi standard. Implementation results applying the aperiodic linear control laws on four P3-DX robots are also included. Both of them demonstrate the advantage of this solution in terms of network accessing and control performance with respect to periodic and non-adaptive self-triggered alternatives.

No MeSH data available.


Related in: MedlinePlus