TY - GEN

T1 - Real-time control under clock offsets between sensors and controllers

AU - Okano, Kunihisa

AU - Wakaiki, Masashi

AU - Hespanha, João P.

N1 - Publisher Copyright:
© 2015 ACM.

PY - 2015/4/14

Y1 - 2015/4/14

N2 - This paper studies the impact of clock mismatches in spatially distributed real-time control systems. We consider a configuration in which sensor measurements are collected by one processor that transmits the measurements to another control/actuation processor through a network, but the two processors do not have a common clock. Due to the clock mismatch, there will be an offset between the actual time at which a measurement is taken and the time reported by the sensor. Our goal is to discover fundamental limitations to the ability to stabilize the control loop arising from the clocks mismatch. We consider time-varying bounded offsets and derive limitations on the offset bound for the stability of the feedback system. For the case of a scalar linear process, there exists a critical limitation, which depends on the level of instability of the plant and the nominal sampling period. In contrast, for the vector linear processes, if the process dynamics has at least two distinct real eigenvalues, then there is no fundamental limitation on the offset bound.

AB - This paper studies the impact of clock mismatches in spatially distributed real-time control systems. We consider a configuration in which sensor measurements are collected by one processor that transmits the measurements to another control/actuation processor through a network, but the two processors do not have a common clock. Due to the clock mismatch, there will be an offset between the actual time at which a measurement is taken and the time reported by the sensor. Our goal is to discover fundamental limitations to the ability to stabilize the control loop arising from the clocks mismatch. We consider time-varying bounded offsets and derive limitations on the offset bound for the stability of the feedback system. For the case of a scalar linear process, there exists a critical limitation, which depends on the level of instability of the plant and the nominal sampling period. In contrast, for the vector linear processes, if the process dynamics has at least two distinct real eigenvalues, then there is no fundamental limitation on the offset bound.

KW - Clock offsets

KW - Fundamental limitations

KW - Networked control systems

UR - http://www.scopus.com/inward/record.url?scp=84940657295&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84940657295&partnerID=8YFLogxK

U2 - 10.1145/2728606.2728613

DO - 10.1145/2728606.2728613

M3 - Conference contribution

AN - SCOPUS:84940657295

T3 - Proceedings of the 18th International Conference on Hybrid Systems: Computation and Control, HSCC 2015

SP - 118

EP - 127

BT - Proceedings of the 18th International Conference on Hybrid Systems

PB - Association for Computing Machinery

T2 - 18th ACM International Conference on Hybrid Systems: Computation and Control, HSCC 2015

Y2 - 14 April 2015 through 16 April 2015

ER -